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Code Issues Packages Projects Releases Wiki Activity

- OpenBSD CVS update

Browse Source 
- [auth-krb4.c]
     -Wall
   - [auth-rh-rsa.c auth-rsa.c hostfile.c hostfile.h key.c key.h match.c]
     [match.h ssh.c ssh.h sshconnect.c sshd.c]
     initial support for DSA keys. ok deraadt@, niels@
   - [cipher.c cipher.h]
     remove unused cipher_attack_detected code
   - [scp.1 ssh-add.1 ssh-agent.1 ssh-keygen.1 ssh.1 sshd.8]
     Fix some formatting problems I missed before.
   - [ssh.1 sshd.8]
     fix spelling errors, From: FreeBSD
   - [ssh.c]
     switch to raw mode only if he _get_ a pty (not if we _want_ a pty).
This commit is contained in:
Damien Miller 2000-03-26 13:04:51 +10:00
parent 2c9279fa66
commit 450a7a1ff4
24 changed files with 965 additions and 545 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
ChangeLog
View File

@ -2,6 +2,20 @@
- Better tests for OpenSSL w/ RSAref - Better tests for OpenSSL w/ RSAref
- Added replacement setenv() function from OpenBSD libc. Suggested by - Added replacement setenv() function from OpenBSD libc. Suggested by
Ben Lindstrom <mouring@pconline.com> Ben Lindstrom <mouring@pconline.com>
- OpenBSD CVS update
- [auth-krb4.c]
-Wall
- [auth-rh-rsa.c auth-rsa.c hostfile.c hostfile.h key.c key.h match.c]
[match.h ssh.c ssh.h sshconnect.c sshd.c]
initial support for DSA keys. ok deraadt@, niels@
- [cipher.c cipher.h]
remove unused cipher_attack_detected code
- [scp.1 ssh-add.1 ssh-agent.1 ssh-keygen.1 ssh.1 sshd.8]
Fix some formatting problems I missed before.
- [ssh.1 sshd.8]
fix spelling errors, From: FreeBSD
- [ssh.c]
switch to raw mode only if he _get_ a pty (not if we _want_ a pty).
20000324 20000324
- Released 1.2.3 - Released 1.2.3

2
Makefile.in
View File

@ -31,7 +31,7 @@ LDFLAGS=-L. @LDFLAGS@
TARGETS=ssh sshd ssh-add ssh-keygen ssh-agent scp $(EXTRA_TARGETS) TARGETS=ssh sshd ssh-add ssh-keygen ssh-agent scp $(EXTRA_TARGETS)
LIBOBJS= atomicio.o authfd.o authfile.o bsd-bindresvport.o bsd-daemon.o bsd-misc.o bsd-mktemp.o bsd-rresvport.o bsd-setenv.o bsd-snprintf.o bsd-strlcat.o bsd-strlcpy.o bufaux.o buffer.o canohost.o channels.o cipher.o compat.o compress.o crc32.o deattack.o fake-getaddrinfo.o fake-getnameinfo.o fingerprint.o hostfile.o log.o match.o mpaux.o nchan.o packet.o radix.o random.o readpass.o rsa.o tildexpand.o ttymodes.o uidswap.o xmalloc.o LIBOBJS= atomicio.o authfd.o authfile.o bsd-bindresvport.o bsd-daemon.o bsd-misc.o bsd-mktemp.o bsd-rresvport.o bsd-setenv.o bsd-snprintf.o bsd-strlcat.o bsd-strlcpy.o bufaux.o buffer.o canohost.o channels.o cipher.o compat.o compress.o crc32.o deattack.o fake-getaddrinfo.o fake-getnameinfo.o fingerprint.o hostfile.o key.o log.o match.o mpaux.o nchan.o packet.o radix.o random.o readpass.o rsa.o tildexpand.o ttymodes.o uidswap.o xmalloc.o
SSHOBJS= ssh.o sshconnect.o log-client.o readconf.o clientloop.o SSHOBJS= ssh.o sshconnect.o log-client.o readconf.o clientloop.o

4
README.Ylonen
View File

@ -1,3 +1,7 @@
[ Please note that this file has not been updated for OpenSSH and
covers the ssh-1.2.12 release from Dec 1995 only. ]
Ssh (Secure Shell) is a program to log into another computer over a Ssh (Secure Shell) is a program to log into another computer over a
network, to execute commands in a remote machine, and to move files network, to execute commands in a remote machine, and to move files
from one machine to another. It provides strong authentication and from one machine to another. It provides strong authentication and

2
auth-krb4.c
View File

@ -139,7 +139,7 @@ int
krb4_init(uid_t uid) krb4_init(uid_t uid)
{ {
static int cleanup_registered = 0; static int cleanup_registered = 0;
char *tkt_root = TKT_ROOT; const char *tkt_root = TKT_ROOT;
struct stat st; struct stat st;
int fd; int fd;

47
auth-rh-rsa.c
View File

@ -15,7 +15,18 @@
*/ */
#include "includes.h" #include "includes.h"
RCSID("$Id: auth-rh-rsa.c,v 1.7 1999/11/25 00:54:57 damien Exp $"); RCSID("$Id: auth-rh-rsa.c,v 1.8 2000/03/26 03:04:52 damien Exp $");
#ifdef HAVE_OPENSSL
#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/dsa.h>
#endif
#ifdef HAVE_SSL
#include <ssl/bn.h>
#include <ssl/rsa.h>
#include <ssl/dsa.h>
#endif
#include "packet.h" #include "packet.h"
#include "ssh.h" #include "ssh.h"
@ -23,37 +34,44 @@ RCSID("$Id: auth-rh-rsa.c,v 1.7 1999/11/25 00:54:57 damien Exp $");
#include "uidswap.h" #include "uidswap.h"
#include "servconf.h" #include "servconf.h"
#include "key.h"
#include "hostfile.h"
/* /*
* Tries to authenticate the user using the .rhosts file and the host using * Tries to authenticate the user using the .rhosts file and the host using
* its host key. Returns true if authentication succeeds. * its host key. Returns true if authentication succeeds.
*/ */
int int
auth_rhosts_rsa(struct passwd *pw, const char *client_user, auth_rhosts_rsa(struct passwd *pw, const char *client_user, RSA *client_host_key)
BIGNUM *client_host_key_e, BIGNUM *client_host_key_n)
{ {
extern ServerOptions options; extern ServerOptions options;
const char *canonical_hostname; const char *canonical_hostname;
HostStatus host_status; HostStatus host_status;
BIGNUM *ke, *kn; Key *client_key, *found;
debug("Trying rhosts with RSA host authentication for %.100s", client_user); debug("Trying rhosts with RSA host authentication for %.100s", client_user);
if (client_host_key == NULL)
return 0;
/* Check if we would accept it using rhosts authentication. */ /* Check if we would accept it using rhosts authentication. */
if (!auth_rhosts(pw, client_user)) if (!auth_rhosts(pw, client_user))
return 0; return 0;
canonical_hostname = get_canonical_hostname(); canonical_hostname = get_canonical_hostname();
debug("Rhosts RSA authentication: canonical host %.900s", debug("Rhosts RSA authentication: canonical host %.900s", canonical_hostname);
canonical_hostname);
/* wrap the RSA key into a 'generic' key */
client_key = key_new(KEY_RSA);
BN_copy(client_key->rsa->e, client_host_key->e);
BN_copy(client_key->rsa->n, client_host_key->n);
found = key_new(KEY_RSA);
/* Check if we know the host and its host key. */ /* Check if we know the host and its host key. */
ke = BN_new();
kn = BN_new();
host_status = check_host_in_hostfile(SSH_SYSTEM_HOSTFILE, canonical_hostname, host_status = check_host_in_hostfile(SSH_SYSTEM_HOSTFILE, canonical_hostname,
client_host_key_e, client_host_key_n, client_key, found);
ke, kn);
/* Check user host file unless ignored. */ /* Check user host file unless ignored. */
if (host_status != HOST_OK && !options.ignore_user_known_hosts) { if (host_status != HOST_OK && !options.ignore_user_known_hosts) {
@ -73,14 +91,13 @@ auth_rhosts_rsa(struct passwd *pw, const char *client_user,
/* XXX race between stat and the following open() */ /* XXX race between stat and the following open() */
temporarily_use_uid(pw->pw_uid); temporarily_use_uid(pw->pw_uid);
host_status = check_host_in_hostfile(user_hostfile, canonical_hostname, host_status = check_host_in_hostfile(user_hostfile, canonical_hostname,
client_host_key_e, client_host_key_n, client_key, found);
ke, kn);
restore_uid(); restore_uid();
} }
xfree(user_hostfile); xfree(user_hostfile);
} }
BN_free(ke); key_free(client_key);
BN_free(kn); key_free(found);
if (host_status != HOST_OK) { if (host_status != HOST_OK) {
debug("Rhosts with RSA host authentication denied: unknown or invalid host key"); debug("Rhosts with RSA host authentication denied: unknown or invalid host key");
@ -90,7 +107,7 @@ auth_rhosts_rsa(struct passwd *pw, const char *client_user,
/* A matching host key was found and is known. */ /* A matching host key was found and is known. */
/* Perform the challenge-response dialog with the client for the host key. */ /* Perform the challenge-response dialog with the client for the host key. */
if (!auth_rsa_challenge_dialog(client_host_key_e, client_host_key_n)) { if (!auth_rsa_challenge_dialog(client_host_key)) {
log("Client on %.800s failed to respond correctly to host authentication.", log("Client on %.800s failed to respond correctly to host authentication.",
canonical_hostname); canonical_hostname);
return 0; return 0;

37
auth-rsa.c
View File

@ -16,7 +16,7 @@
*/ */
#include "includes.h" #include "includes.h"
RCSID("$Id: auth-rsa.c,v 1.13 2000/03/09 10:27:50 damien Exp $"); RCSID("$Id: auth-rsa.c,v 1.14 2000/03/26 03:04:52 damien Exp $");
#include "rsa.h" #include "rsa.h"
#include "packet.h" #include "packet.h"
@ -24,6 +24,7 @@ RCSID("$Id: auth-rsa.c,v 1.13 2000/03/09 10:27:50 damien Exp $");
#include "ssh.h" #include "ssh.h"
#include "mpaux.h" #include "mpaux.h"
#include "uidswap.h" #include "uidswap.h"
#include "match.h"
#include "servconf.h" #include "servconf.h"
#ifdef HAVE_OPENSSL #ifdef HAVE_OPENSSL
@ -66,10 +67,9 @@ extern unsigned char session_id[16];
*/ */
int int
auth_rsa_challenge_dialog(BIGNUM *e, BIGNUM *n) auth_rsa_challenge_dialog(RSA *pk)
{ {
BIGNUM *challenge, *encrypted_challenge; BIGNUM *challenge, *encrypted_challenge;
RSA *pk;
BN_CTX *ctx; BN_CTX *ctx;
unsigned char buf[32], mdbuf[16], response[16]; unsigned char buf[32], mdbuf[16], response[16];
MD5_CTX md; MD5_CTX md;
@ -82,19 +82,11 @@ auth_rsa_challenge_dialog(BIGNUM *e, BIGNUM *n)
/* Generate a random challenge. */ /* Generate a random challenge. */
BN_rand(challenge, 256, 0, 0); BN_rand(challenge, 256, 0, 0);
ctx = BN_CTX_new(); ctx = BN_CTX_new();
BN_mod(challenge, challenge, n, ctx); BN_mod(challenge, challenge, pk->n, ctx);
BN_CTX_free(ctx); BN_CTX_free(ctx);
/* Create the public key data structure. */
pk = RSA_new();
pk->e = BN_new();
BN_copy(pk->e, e);
pk->n = BN_new();
BN_copy(pk->n, n);
/* Encrypt the challenge with the public key. */ /* Encrypt the challenge with the public key. */
rsa_public_encrypt(encrypted_challenge, challenge, pk); rsa_public_encrypt(encrypted_challenge, challenge, pk);
RSA_free(pk);
/* Send the encrypted challenge to the client. */ /* Send the encrypted challenge to the client. */
packet_start(SSH_SMSG_AUTH_RSA_CHALLENGE); packet_start(SSH_SMSG_AUTH_RSA_CHALLENGE);
@ -146,7 +138,7 @@ auth_rsa(struct passwd *pw, BIGNUM *client_n)
FILE *f; FILE *f;
unsigned long linenum = 0; unsigned long linenum = 0;
struct stat st; struct stat st;
BIGNUM *e, *n; RSA *pk;
/* Temporarily use the user's uid. */ /* Temporarily use the user's uid. */
temporarily_use_uid(pw->pw_uid); temporarily_use_uid(pw->pw_uid);
@ -208,8 +200,9 @@ auth_rsa(struct passwd *pw, BIGNUM *client_n)
/* Flag indicating whether authentication has succeeded. */ /* Flag indicating whether authentication has succeeded. */
authenticated = 0; authenticated = 0;
e = BN_new(); pk = RSA_new();
n = BN_new(); pk->e = BN_new();
pk->n = BN_new();
/* /*
* Go though the accepted keys, looking for the current key. If * Go though the accepted keys, looking for the current key. If
@ -247,7 +240,7 @@ auth_rsa(struct passwd *pw, BIGNUM *client_n)
options = NULL; options = NULL;
/* Parse the key from the line. */ /* Parse the key from the line. */
if (!auth_rsa_read_key(&cp, &bits, e, n)) { if (!auth_rsa_read_key(&cp, &bits, pk->e, pk->n)) {
debug("%.100s, line %lu: bad key syntax", debug("%.100s, line %lu: bad key syntax",
SSH_USER_PERMITTED_KEYS, linenum); SSH_USER_PERMITTED_KEYS, linenum);
packet_send_debug("%.100s, line %lu: bad key syntax", packet_send_debug("%.100s, line %lu: bad key syntax",
@ -257,19 +250,20 @@ auth_rsa(struct passwd *pw, BIGNUM *client_n)
/* cp now points to the comment part. */ /* cp now points to the comment part. */
/* Check if the we have found the desired key (identified by its modulus). */ /* Check if the we have found the desired key (identified by its modulus). */
if (BN_cmp(n, client_n) != 0) if (BN_cmp(pk->n, client_n) != 0)
continue; continue;
/* check the real bits */ /* check the real bits */
if (bits != BN_num_bits(n)) if (bits != BN_num_bits(pk->n))
log("Warning: %s, line %ld: keysize mismatch: " log("Warning: %s, line %ld: keysize mismatch: "
"actual %d vs. announced %d.", "actual %d vs. announced %d.",
file, linenum, BN_num_bits(n), bits); file, linenum, BN_num_bits(pk->n), bits);
/* We have found the desired key. */ /* We have found the desired key. */
/* Perform the challenge-response dialog for this key. */ /* Perform the challenge-response dialog for this key. */
if (!auth_rsa_challenge_dialog(e, n)) { if (!auth_rsa_challenge_dialog(pk)) {
/* Wrong response. */ /* Wrong response. */
verbose("Wrong response to RSA authentication challenge."); verbose("Wrong response to RSA authentication challenge.");
packet_send_debug("Wrong response to RSA authentication challenge."); packet_send_debug("Wrong response to RSA authentication challenge.");
@ -472,8 +466,7 @@ auth_rsa(struct passwd *pw, BIGNUM *client_n)
/* Close the file. */ /* Close the file. */
fclose(f); fclose(f);
BN_clear_free(n); RSA_free(pk);
BN_clear_free(e);
if (authenticated) if (authenticated)
packet_send_debug("RSA authentication accepted."); packet_send_debug("RSA authentication accepted.");

16
cipher.c
View File

@ -12,7 +12,7 @@
*/ */
#include "includes.h" #include "includes.h"
RCSID("$Id: cipher.c,v 1.13 2000/03/09 10:27:50 damien Exp $"); RCSID("$Id: cipher.c,v 1.14 2000/03/26 03:04:52 damien Exp $");
#include "ssh.h" #include "ssh.h"
#include "cipher.h" #include "cipher.h"
@ -110,18 +110,6 @@ swap_bytes(const unsigned char *src, unsigned char *dst_, int n)
} }
} }
void (*cipher_attack_detected) (const char *fmt,...) = fatal;
static inline void
detect_cbc_attack(const unsigned char *src,
unsigned int len)
{
return;
log("CRC-32 CBC insertion attack detected");
cipher_attack_detected("CRC-32 CBC insertion attack detected");
}
/* /*
* Names of all encryption algorithms. * Names of all encryption algorithms.
* These must match the numbers defined in cipher.h. * These must match the numbers defined in cipher.h.
@ -304,7 +292,6 @@ cipher_decrypt(CipherContext *context, unsigned char *dest,
break; break;
case SSH_CIPHER_3DES: case SSH_CIPHER_3DES:
/* CRC-32 attack? */
SSH_3CBC_DECRYPT(context->u.des3.key1, SSH_3CBC_DECRYPT(context->u.des3.key1,
context->u.des3.key2, &context->u.des3.iv2, context->u.des3.key2, &context->u.des3.iv2,
context->u.des3.key3, &context->u.des3.iv3, context->u.des3.key3, &context->u.des3.iv3,
@ -312,7 +299,6 @@ cipher_decrypt(CipherContext *context, unsigned char *dest,
break; break;
case SSH_CIPHER_BLOWFISH: case SSH_CIPHER_BLOWFISH:
detect_cbc_attack(src, len);
swap_bytes(src, dest, len); swap_bytes(src, dest, len);
BF_cbc_encrypt((void *) dest, dest, len, BF_cbc_encrypt((void *) dest, dest, len,
&context->u.bf.key, context->u.bf.iv, &context->u.bf.key, context->u.bf.iv,

8
cipher.h
View File

@ -11,7 +11,7 @@
* *
*/ */
/* RCSID("$Id: cipher.h,v 1.5 1999/11/25 00:54:58 damien Exp $"); */ /* RCSID("$Id: cipher.h,v 1.6 2000/03/26 03:04:52 damien Exp $"); */
#ifndef CIPHER_H #ifndef CIPHER_H
#define CIPHER_H #define CIPHER_H
@ -96,10 +96,4 @@ void
cipher_decrypt(CipherContext * context, unsigned char *dest, cipher_decrypt(CipherContext * context, unsigned char *dest,
const unsigned char *src, unsigned int len); const unsigned char *src, unsigned int len);
/*
* If and CRC-32 attack is detected this function is called. Defaults to
* fatal, changed to packet_disconnect in sshd and ssh.
*/
extern void (*cipher_attack_detected) (const char *fmt, ...);
#endif /* CIPHER_H */ #endif /* CIPHER_H */

202
hostfile.c
View File

@ -14,63 +14,32 @@
*/ */
#include "includes.h" #include "includes.h"
RCSID("$OpenBSD: hostfile.c,v 1.13 2000/02/18 10:20:20 markus Exp $"); RCSID("$OpenBSD: hostfile.c,v 1.14 2000/03/23 22:15:33 markus Exp $");
#ifdef HAVE_OPENSSL
#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/dsa.h>
#endif
#ifdef HAVE_SSL
#include <ssl/bn.h>
#include <ssl/rsa.h>
#include <ssl/dsa.h>
#endif
#include "packet.h" #include "packet.h"
#include "match.h"
#include "ssh.h" #include "ssh.h"
#include "key.h"
#include "hostfile.h"
/* /*
* Reads a multiple-precision integer in decimal from the buffer, and advances * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the
* the pointer. The integer must already be initialized. This function is * pointer over the key. Skips any whitespace at the beginning and at end.
* permitted to modify the buffer. This leaves *cpp to point just beyond the
* last processed (and maybe modified) character. Note that this may modify
* the buffer containing the number.
*/ */
int int
auth_rsa_read_bignum(char **cpp, BIGNUM * value) hostfile_read_key(char **cpp, unsigned int *bitsp, Key *ret)
{
char *cp = *cpp;
int old;
/* Skip any leading whitespace. */
for (; *cp == ' ' || *cp == '\t'; cp++)
;
/* Check that it begins with a decimal digit. */
if (*cp < '0' || *cp > '9')
return 0;
/* Save starting position. */
*cpp = cp;
/* Move forward until all decimal digits skipped. */
for (; *cp >= '0' && *cp <= '9'; cp++)
;
/* Save the old terminating character, and replace it by \0. */
old = *cp;
*cp = 0;
/* Parse the number. */
if (BN_dec2bn(&value, *cpp) == 0)
return 0;
/* Restore old terminating character. */
*cp = old;
/* Move beyond the number and return success. */
*cpp = cp;
return 1;
}
/*
* Parses an RSA key (number of bits, e, n) from a string. Moves the pointer
* over the key. Skips any whitespace at the beginning and at end.
*/
int
auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n)
{ {
unsigned int bits; unsigned int bits;
char *cp; char *cp;
@ -85,12 +54,7 @@ auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n)
for (bits = 0; *cp >= '0' && *cp <= '9'; cp++) for (bits = 0; *cp >= '0' && *cp <= '9'; cp++)
bits = 10 * bits + *cp - '0'; bits = 10 * bits + *cp - '0';
/* Get public exponent. */ if (!key_read(ret, bits, &cp))
if (!auth_rsa_read_bignum(&cp, e))
return 0;
/* Get public modulus. */
if (!auth_rsa_read_bignum(&cp, n))
return 0; return 0;
/* Skip trailing whitespace. */ /* Skip trailing whitespace. */
@ -103,63 +67,30 @@ auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n)
return 1; return 1;
} }
/* int
* Tries to match the host name (which must be in all lowercase) against the auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n)
* comma-separated sequence of subpatterns (each possibly preceded by ! to {
* indicate negation). Returns true if there is a positive match; zero Key *k = key_new(KEY_RSA);
* otherwise. int ret = hostfile_read_key(cpp, bitsp, k);
*/ BN_copy(e, k->rsa->e);
BN_copy(n, k->rsa->n);
key_free(k);
return ret;
}
int int
match_hostname(const char *host, const char *pattern, unsigned int len) hostfile_check_key(int bits, Key *key, const char *host, const char *filename, int linenum)
{ {
char sub[1024]; if (key == NULL || key->type != KEY_RSA || key->rsa == NULL)
int negated; return 1;
int got_positive; if (bits != BN_num_bits(key->rsa->n)) {
unsigned int i, subi; error("Warning: %s, line %d: keysize mismatch for host %s: "
"actual %d vs. announced %d.",
got_positive = 0; filename, linenum, host, BN_num_bits(key->rsa->n), bits);
for (i = 0; i < len;) { error("Warning: replace %d with %d in %s, line %d.",
/* Check if the subpattern is negated. */ bits, BN_num_bits(key->rsa->n), filename, linenum);
if (pattern[i] == '!') {
negated = 1;
i++;
} else
negated = 0;
/*
* Extract the subpattern up to a comma or end. Convert the
* subpattern to lowercase.
*/
for (subi = 0;
i < len && subi < sizeof(sub) - 1 && pattern[i] != ',';
subi++, i++)
sub[subi] = isupper(pattern[i]) ? tolower(pattern[i]) : pattern[i];
/* If subpattern too long, return failure (no match). */
if (subi >= sizeof(sub) - 1)
return 0;
/* If the subpattern was terminated by a comma, skip the comma. */
if (i < len && pattern[i] == ',')
i++;
/* Null-terminate the subpattern. */
sub[subi] = '\0';
/* Try to match the subpattern against the host name. */
if (match_pattern(host, sub)) {
if (negated)
return 0; /* Fail */
else
got_positive = 1;
} }
} return 1;
/*
* Return success if got a positive match. If there was a negative
* match, we have already returned zero and never get here.
*/
return got_positive;
} }
/* /*
@ -170,8 +101,7 @@ match_hostname(const char *host, const char *pattern, unsigned int len)
*/ */
HostStatus HostStatus
check_host_in_hostfile(const char *filename, const char *host, check_host_in_hostfile(const char *filename, const char *host, Key *key, Key *found)
BIGNUM * e, BIGNUM * n, BIGNUM * ke, BIGNUM * kn)
{ {
FILE *f; FILE *f;
char line[8192]; char line[8192];
@ -180,6 +110,8 @@ check_host_in_hostfile(const char *filename, const char *host,
char *cp, *cp2; char *cp, *cp2;
HostStatus end_return; HostStatus end_return;
if (key == NULL)
fatal("no key to look up");
/* Open the file containing the list of known hosts. */ /* Open the file containing the list of known hosts. */
f = fopen(filename, "r"); f = fopen(filename, "r");
if (!f) if (!f)
@ -221,18 +153,13 @@ check_host_in_hostfile(const char *filename, const char *host,
* Extract the key from the line. This will skip any leading * Extract the key from the line. This will skip any leading
* whitespace. Ignore badly formatted lines. * whitespace. Ignore badly formatted lines.
*/ */
if (!auth_rsa_read_key(&cp, &kbits, ke, kn)) if (!hostfile_read_key(&cp, &kbits, found))
continue;
if (!hostfile_check_key(kbits, found, host, filename, linenum))
continue; continue;
if (kbits != BN_num_bits(kn)) {
error("Warning: %s, line %d: keysize mismatch for host %s: "
"actual %d vs. announced %d.",
filename, linenum, host, BN_num_bits(kn), kbits);
error("Warning: replace %d with %d in %s, line %d.",
kbits, BN_num_bits(kn), filename, linenum);
}
/* Check if the current key is the same as the given key. */ /* Check if the current key is the same as the given key. */
if (BN_cmp(ke, e) == 0 && BN_cmp(kn, n) == 0) { if (key_equal(key, found)) {
/* Ok, they match. */ /* Ok, they match. */
fclose(f); fclose(f);
return HOST_OK; return HOST_OK;
@ -260,41 +187,28 @@ check_host_in_hostfile(const char *filename, const char *host,
*/ */
int int
add_host_to_hostfile(const char *filename, const char *host, add_host_to_hostfile(const char *filename, const char *host, Key *key)
BIGNUM * e, BIGNUM * n)
{ {
FILE *f; FILE *f;
char *buf; int success = 0;
unsigned int bits;
if (key == NULL)
return 1;
/* Open the file for appending. */ /* Open the file for appending. */
f = fopen(filename, "a"); f = fopen(filename, "a");
if (!f) if (!f)
return 0; return 0;
/* size of modulus 'n' */ fprintf(f, "%s ", host);
bits = BN_num_bits(n); if (key_write(key, f)) {
fprintf(f, "\n");
/* Print the host name and key to the file. */ success = 1;
fprintf(f, "%s %u ", host, bits); } else {
buf = BN_bn2dec(e); error("add_host_to_hostfile: saving key failed");
if (buf == NULL) {
error("add_host_to_hostfile: BN_bn2dec(e) failed");
fclose(f);
return 0;
} }
fprintf(f, "%s ", buf);
free(buf);
buf = BN_bn2dec(n);
if (buf == NULL) {
error("add_host_to_hostfile: BN_bn2dec(n) failed");
fclose(f);
return 0;
}
fprintf(f, "%s\n", buf);
free(buf);
/* Close the file. */ /* Close the file. */
fclose(f); fclose(f);
return 1; return success;
} }

22
hostfile.h Normal file
View File

@ -0,0 +1,22 @@
#ifndef HOSTFILE_H
#define HOSTFILE_H
/*
* Checks whether the given host is already in the list of our known hosts.
* Returns HOST_OK if the host is known and has the specified key, HOST_NEW
* if the host is not known, and HOST_CHANGED if the host is known but used
* to have a different host key. The host must be in all lowercase.
*/
typedef enum {
HOST_OK, HOST_NEW, HOST_CHANGED
} HostStatus;
HostStatus
check_host_in_hostfile(const char *filename, const char *host, Key *key, Key *found);
/*
* Appends an entry to the host file. Returns false if the entry could not
* be appended.
*/
int add_host_to_hostfile(const char *filename, const char *host, Key *key);
#endif

301
key.c Normal file
View File

@ -0,0 +1,301 @@
/*
* Copyright (c) 2000 Markus Friedl. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Markus Friedl.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* read_bignum():
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
*/
#include "includes.h"
#ifdef HAVE_OPENSSL
#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/dsa.h>
#include <openssl/evp.h>
#endif
#ifdef HAVE_SSL
#include <ssl/bn.h>
#include <ssl/rsa.h>
#include <ssl/dsa.h>
#include <ssl/evp.h>
#endif
#include "ssh.h"
#include "xmalloc.h"
#include "key.h"
Key *
key_new(int type)
{
Key *k;
RSA *rsa;
DSA *dsa;
k = xmalloc(sizeof(*k));
k->type = type;
switch (k->type) {
case KEY_RSA:
rsa = RSA_new();
rsa->n = BN_new();
rsa->e = BN_new();
k->rsa = rsa;
break;
case KEY_DSA:
dsa = DSA_new();
dsa->p = BN_new();
dsa->q = BN_new();
dsa->g = BN_new();
dsa->pub_key = BN_new();
k->dsa = dsa;
break;
case KEY_EMPTY:
k->dsa = NULL;
k->rsa = NULL;
break;
default:
fatal("key_new: bad key type %d", k->type);
break;
}
return k;
}
void
key_free(Key *k)
{
switch (k->type) {
case KEY_RSA:
if (k->rsa != NULL)
RSA_free(k->rsa);
k->rsa = NULL;
break;
case KEY_DSA:
if (k->dsa != NULL)
DSA_free(k->dsa);
k->dsa = NULL;
break;
default:
fatal("key_free: bad key type %d", k->type);
break;
}
xfree(k);
}
int
key_equal(Key *a, Key *b)
{
if (a == NULL || b == NULL || a->type != b->type)
return 0;
switch (a->type) {
case KEY_RSA:
return a->rsa != NULL && b->rsa != NULL &&
BN_cmp(a->rsa->e, b->rsa->e) == 0 &&
BN_cmp(a->rsa->n, b->rsa->n) == 0;
break;
case KEY_DSA:
return a->dsa != NULL && b->dsa != NULL &&
BN_cmp(a->dsa->p, b->dsa->p) == 0 &&
BN_cmp(a->dsa->q, b->dsa->q) == 0 &&
BN_cmp(a->dsa->g, b->dsa->g) == 0 &&
BN_cmp(a->dsa->pub_key, b->dsa->pub_key) == 0;
break;
default:
fatal("key_free: bad key type %d", a->type);
break;
}
return 0;
}
#define FPRINT "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x"
/*
* Generate key fingerprint in ascii format.
* Based on ideas and code from Bjoern Groenvall <bg@sics.se>
*/
char *
key_fingerprint(Key *k)
{
static char retval[80];
unsigned char *buf = NULL;
int len = 0;
int nlen, elen, plen, qlen, glen, publen;
switch (k->type) {
case KEY_RSA:
nlen = BN_num_bytes(k->rsa->n);
elen = BN_num_bytes(k->rsa->e);
len = nlen + elen;
buf = xmalloc(len);
BN_bn2bin(k->rsa->n, buf);
BN_bn2bin(k->rsa->e, buf + nlen);
break;
case KEY_DSA:
plen = BN_num_bytes(k->dsa->p);
qlen = BN_num_bytes(k->dsa->q);
glen = BN_num_bytes(k->dsa->g);
publen = BN_num_bytes(k->dsa->pub_key);
len = qlen + qlen + glen + publen;
buf = xmalloc(len);
BN_bn2bin(k->dsa->p, buf);
BN_bn2bin(k->dsa->q, buf + plen);
BN_bn2bin(k->dsa->g, buf + plen + qlen);
BN_bn2bin(k->dsa->pub_key , buf + plen + qlen + glen);
break;
default:
fatal("key_fingerprint: bad key type %d", k->type);
break;
}
if (buf != NULL) {
unsigned char d[16];
EVP_MD_CTX md;
EVP_DigestInit(&md, EVP_md5());
EVP_DigestUpdate(&md, buf, len);
EVP_DigestFinal(&md, d, NULL);
snprintf(retval, sizeof(retval), FPRINT,
d[0], d[1], d[2], d[3], d[4], d[5], d[6], d[7],
d[8], d[9], d[10], d[11], d[12], d[13], d[14], d[15]);
memset(buf, 0, len);
xfree(buf);
}
return retval;
}
/*
* Reads a multiple-precision integer in decimal from the buffer, and advances
* the pointer. The integer must already be initialized. This function is
* permitted to modify the buffer. This leaves *cpp to point just beyond the
* last processed (and maybe modified) character. Note that this may modify
* the buffer containing the number.
*/
int
read_bignum(char **cpp, BIGNUM * value)
{
char *cp = *cpp;
int old;
/* Skip any leading whitespace. */
for (; *cp == ' ' || *cp == '\t'; cp++)
;
/* Check that it begins with a decimal digit. */
if (*cp < '0' || *cp > '9')
return 0;
/* Save starting position. */
*cpp = cp;
/* Move forward until all decimal digits skipped. */
for (; *cp >= '0' && *cp <= '9'; cp++)
;
/* Save the old terminating character, and replace it by \0. */
old = *cp;
*cp = 0;
/* Parse the number. */
if (BN_dec2bn(&value, *cpp) == 0)
return 0;
/* Restore old terminating character. */
*cp = old;
/* Move beyond the number and return success. */
*cpp = cp;
return 1;
}
int
write_bignum(FILE *f, BIGNUM *num)
{
char *buf = BN_bn2dec(num);
if (buf == NULL) {
error("write_bignum: BN_bn2dec() failed");
return 0;
}
fprintf(f, " %s", buf);
free(buf);
return 1;
}
int
key_read(Key *ret, unsigned int bits, char **cpp)
{
switch(ret->type) {
case KEY_RSA:
if (bits == 0)
return 0;
/* Get public exponent, public modulus. */
if (!read_bignum(cpp, ret->rsa->e))
return 0;
if (!read_bignum(cpp, ret->rsa->n))
return 0;
break;
case KEY_DSA:
if (bits != 0)
return 0;
if (!read_bignum(cpp, ret->dsa->p))
return 0;
if (!read_bignum(cpp, ret->dsa->q))
return 0;
if (!read_bignum(cpp, ret->dsa->g))
return 0;
if (!read_bignum(cpp, ret->dsa->pub_key))
return 0;
break;
default:
fatal("bad key type: %d", ret->type);
break;
}
return 1;
}
int
key_write(Key *key, FILE *f)
{
int success = 0;
unsigned int bits = 0;
if (key->type == KEY_RSA && key->rsa != NULL) {
/* size of modulus 'n' */
bits = BN_num_bits(key->rsa->n);
fprintf(f, "%u", bits);
if (write_bignum(f, key->rsa->e) &&
write_bignum(f, key->rsa->n)) {
success = 1;
} else {
error("key_write: failed for RSA key");
}
} else if (key->type == KEY_DSA && key->dsa != NULL) {
/* bits == 0 means DSA key */
bits = 0;
fprintf(f, "%u", bits);
if (write_bignum(f, key->dsa->p) &&
write_bignum(f, key->dsa->q) &&
write_bignum(f, key->dsa->g) &&
write_bignum(f, key->dsa->pub_key)) {
success = 1;
} else {
error("key_write: failed for DSA key");
}
}
return success;
}

23
key.h Normal file
View File

@ -0,0 +1,23 @@
#ifndef KEY_H
#define KEY_H
typedef struct Key Key;
enum types {
KEY_RSA,
KEY_DSA,
KEY_EMPTY
};
struct Key {
int type;
RSA *rsa;
DSA *dsa;
};
Key *key_new(int type);
void key_free(Key *k);
int key_equal(Key *a, Key *b);
char *key_fingerprint(Key *k);
int key_write(Key *key, FILE *f);
int key_read(Key *key, unsigned int bits, char **cpp);
#endif

61
match.c
View File

@ -14,7 +14,7 @@
*/ */
#include "includes.h" #include "includes.h"
RCSID("$Id: match.c,v 1.3 1999/11/25 00:54:59 damien Exp $"); RCSID("$Id: match.c,v 1.4 2000/03/26 03:04:53 damien Exp $");
#include "ssh.h" #include "ssh.h"
@ -80,3 +80,62 @@ match_pattern(const char *s, const char *pattern)
} }
/* NOTREACHED */ /* NOTREACHED */
} }
/*
* Tries to match the host name (which must be in all lowercase) against the
* comma-separated sequence of subpatterns (each possibly preceded by ! to
* indicate negation). Returns true if there is a positive match; zero
* otherwise.
*/
int
match_hostname(const char *host, const char *pattern, unsigned int len)
{
char sub[1024];
int negated;
int got_positive;
unsigned int i, subi;
got_positive = 0;
for (i = 0; i < len;) {
/* Check if the subpattern is negated. */
if (pattern[i] == '!') {
negated = 1;
i++;
} else
negated = 0;
/*
* Extract the subpattern up to a comma or end. Convert the
* subpattern to lowercase.
*/
for (subi = 0;
i < len && subi < sizeof(sub) - 1 && pattern[i] != ',';
subi++, i++)
sub[subi] = isupper(pattern[i]) ? tolower(pattern[i]) : pattern[i];
/* If subpattern too long, return failure (no match). */
if (subi >= sizeof(sub) - 1)
return 0;
/* If the subpattern was terminated by a comma, skip the comma. */
if (i < len && pattern[i] == ',')
i++;
/* Null-terminate the subpattern. */
sub[subi] = '\0';
/* Try to match the subpattern against the host name. */
if (match_pattern(host, sub)) {
if (negated)
return 0; /* Fail */
else
got_positive = 1;
}
}
/*
* Return success if got a positive match. If there was a negative
* match, we have already returned zero and never get here.
*/
return got_positive;
}

18
match.h Normal file
View File

@ -0,0 +1,18 @@
#ifndef MATCH_H
#define MATCH_H
/*
* Returns true if the given string matches the pattern (which may contain ?
* and * as wildcards), and zero if it does not match.
*/
int match_pattern(const char *s, const char *pattern);
/*
* Tries to match the host name (which must be in all lowercase) against the
* comma-separated sequence of subpatterns (each possibly preceded by ! to
* indicate negation). Returns true if there is a positive match; zero
* otherwise.
*/
int match_hostname(const char *host, const char *pattern, unsigned int len);
#endif

29
scp.1
View File

@ -9,7 +9,7 @@
.\" .\"
.\" Created: Sun May 7 00:14:37 1995 ylo .\" Created: Sun May 7 00:14:37 1995 ylo
.\" .\"
.\" $Id: scp.1,v 1.5 2000/01/20 12:13:36 damien Exp $ .\" $Id: scp.1,v 1.6 2000/03/26 03:04:53 damien Exp $
.\" .\"
.Dd September 25, 1999 .Dd September 25, 1999
.Dt SCP 1 .Dt SCP 1
@ -38,7 +38,8 @@
.Sm on .Sm on
.Sh DESCRIPTION .Sh DESCRIPTION
.Nm .Nm
copies files between hosts on a network. It uses copies files between hosts on a network.
It uses
.Xr ssh 1 .Xr ssh 1
for data transfer, and uses the same authentication and provides the for data transfer, and uses the same authentication and provides the
same security as same security as
@ -50,18 +51,19 @@ will ask for passwords or passphrases if they are needed for
authentication. authentication.
.Pp .Pp
Any file name may contain a host and user specification to indicate Any file name may contain a host and user specification to indicate
that the file is to be copied to/from that host. Copies between two that the file is to be copied to/from that host.
remote hosts are permitted. Copies between two remote hosts are permitted.
.Pp .Pp
The options are as follows: The options are as follows:
.Bl -tag -width Ds .Bl -tag -width Ds
.It Fl c Ar cipher .It Fl c Ar cipher
Selects the cipher to use for encrypting the data transfer. This Selects the cipher to use for encrypting the data transfer.
option is directly passed to This option is directly passed to
.Xr ssh 1 . .Xr ssh 1 .
.It Fl i Ar identity_file .It Fl i Ar identity_file
Selects the file from which the identity (private key) for RSA Selects the file from which the identity (private key) for RSA
authentication is read. This option is directly passed to authentication is read.
This option is directly passed to
.Xr ssh 1 . .Xr ssh 1 .
.It Fl p .It Fl p
Preserves modification times, access times, and modes from the Preserves modification times, access times, and modes from the
@ -69,25 +71,28 @@ original file.
.It Fl r .It Fl r
Recursively copy entire directories. Recursively copy entire directories.
.It Fl v .It Fl v
Verbose mode. Causes Verbose mode.
Causes
.Nm .Nm
and and
.Xr ssh 1 .Xr ssh 1
to print debugging messages about their progress. This is helpful in to print debugging messages about their progress.
This is helpful in
debugging connection, authentication, and configuration problems. debugging connection, authentication, and configuration problems.
.It Fl B .It Fl B
Selects batch mode (prevents asking for passwords or passphrases). Selects batch mode (prevents asking for passwords or passphrases).
.It Fl q .It Fl q
Disables the progress meter. Disables the progress meter.
.It Fl C .It Fl C
Compression enable. Passes the Compression enable.
Passes the
.Fl C .Fl C
flag to flag to
.Xr ssh 1 .Xr ssh 1
to enable compression. to enable compression.
.It Fl P Ar port .It Fl P Ar port
Specifies the port to connect to on the remote host. Note that this Specifies the port to connect to on the remote host.
option is written with a capital Note that this option is written with a capital
.Sq P , .Sq P ,
because because
.Fl p .Fl p

31
ssh-add.1
View File

@ -9,7 +9,7 @@
.\" .\"
.\" Created: Sat Apr 22 23:55:14 1995 ylo .\" Created: Sat Apr 22 23:55:14 1995 ylo
.\" .\"
.\" $Id: ssh-add.1,v 1.9 2000/01/22 08:57:40 damien Exp $ .\" $Id: ssh-add.1,v 1.10 2000/03/26 03:04:53 damien Exp $
.\" .\"
.Dd September 25, 1999 .Dd September 25, 1999
.Dt SSH-ADD 1 .Dt SSH-ADD 1
@ -27,8 +27,8 @@ adds identities to the authentication agent,
.Xr ssh-agent 1 . .Xr ssh-agent 1 .
When run without arguments, it adds the file When run without arguments, it adds the file
.Pa $HOME/.ssh/identity . .Pa $HOME/.ssh/identity .
Alternative file names can be given on the Alternative file names can be given on the command line.
command line. If any file requires a passphrase, If any file requires a passphrase,
.Nm .Nm
asks for the passphrase from the user. asks for the passphrase from the user.
The Passphrase it is read from the user's tty. The Passphrase it is read from the user's tty.
@ -52,15 +52,15 @@ Deletes all identities from the agent.
.Sh FILES .Sh FILES
.Bl -tag -width Ds .Bl -tag -width Ds
.It Pa $HOME/.ssh/identity .It Pa $HOME/.ssh/identity
Contains the RSA authentication identity of the user. This file Contains the RSA authentication identity of the user.
should not be readable by anyone but the user. This file should not be readable by anyone but the user.
Note that Note that
.Nm .Nm
ignores this file if it is accessible by others. ignores this file if it is accessible by others.
It is possible to It is possible to
specify a passphrase when generating the key; that passphrase will be specify a passphrase when generating the key; that passphrase will be
used to encrypt the private part of this file. This is the used to encrypt the private part of this file.
default file added by This is the default file added by
.Nm .Nm
when no other files have been specified. when no other files have been specified.
.Pp .Pp
@ -70,7 +70,8 @@ when no other files have been specified.
If If
.Nm .Nm
needs a passphrase, it will read the passphrase from the current needs a passphrase, it will read the passphrase from the current
terminal if it was run from a terminal. If terminal if it was run from a terminal.
If
.Nm .Nm
does not have a terminal associated with it but does not have a terminal associated with it but
.Ev DISPLAY .Ev DISPLAY
@ -78,12 +79,13 @@ and
.Ev SSH_ASKPASS .Ev SSH_ASKPASS
are set, it will execute the program specified by are set, it will execute the program specified by
.Ev SSH_ASKPASS .Ev SSH_ASKPASS
and open an X11 window to read the passphrase. This is particularly and open an X11 window to read the passphrase.
useful when calling This is particularly useful when calling
.Nm .Nm
from a from a
.Pa .Xsession .Pa .Xsession
or related script. (Note that on some machines it or related script.
(Note that on some machines it
may be necessary to redirect the input from may be necessary to redirect the input from
.Pa /dev/null .Pa /dev/null
to make this work.) to make this work.)
@ -92,9 +94,10 @@ Tatu Ylonen <ylo@cs.hut.fi>
.Pp .Pp
OpenSSH OpenSSH
is a derivative of the original (free) ssh 1.2.12 release, but with bugs is a derivative of the original (free) ssh 1.2.12 release, but with bugs
removed and newer features re-added. Rapidly after the 1.2.12 release, removed and newer features re-added.
newer versions bore successively more restrictive licenses. This version Rapidly after the 1.2.12 release,
of OpenSSH newer versions bore successively more restrictive licenses.
This version of OpenSSH
.Bl -bullet .Bl -bullet
.It .It
has all components of a restrictive nature (i.e., patents, see has all components of a restrictive nature (i.e., patents, see

52
ssh-agent.1
View File

@ -1,4 +1,4 @@
.\" $OpenBSD: ssh-agent.1,v 1.9 2000/01/22 02:17:50 aaron Exp $ .\" $OpenBSD: ssh-agent.1,v 1.10 2000/03/23 21:10:10 aaron Exp $
.\" .\"
.\" -*- nroff -*- .\" -*- nroff -*-
.\" .\"
@ -27,12 +27,13 @@
.Oc .Oc
.Sh DESCRIPTION .Sh DESCRIPTION
.Nm .Nm
is a program to hold authentication private keys. The is a program to hold authentication private keys.
idea is that The idea is that
.Nm .Nm
is started in the beginning of an X-session or a login session, and is started in the beginning of an X-session or a login session, and
all other windows or programs are started as clients to the ssh-agent all other windows or programs are started as clients to the ssh-agent
program. Through use of environment variables the agent can be located program.
Through use of environment variables the agent can be located
and automatically used for RSA authentication when logging in to other and automatically used for RSA authentication when logging in to other
machines using machines using
.Xr ssh 1 . .Xr ssh 1 .
@ -60,30 +61,34 @@ environment variable).
If a commandline is given, this is executed as a subprocess of the agent. If a commandline is given, this is executed as a subprocess of the agent.
When the command dies, so does the agent. When the command dies, so does the agent.
.Pp .Pp
The agent initially does not have any private keys. Keys are added The agent initially does not have any private keys.
using Keys are added using
.Xr ssh-add 1 . .Xr ssh-add 1 .
When executed without arguments, When executed without arguments,
.Xr ssh-add 1 .Xr ssh-add 1
adds the adds the
.Pa $HOME/.ssh/identity .Pa $HOME/.ssh/identity
file. If the identity has a passphrase, file.
If the identity has a passphrase,
.Xr ssh-add 1 .Xr ssh-add 1
asks for the passphrase (using a small X11 application if running asks for the passphrase (using a small X11 application if running
under X11, or from the terminal if running without X). It then sends under X11, or from the terminal if running without X).
the identity to the agent. Several identities can be stored in the It then sends the identity to the agent.
Several identities can be stored in the
agent; the agent can automatically use any of these identities. agent; the agent can automatically use any of these identities.
.Ic ssh-add -l .Ic ssh-add -l
displays the identities currently held by the agent. displays the identities currently held by the agent.
.Pp .Pp
The idea is that the agent is run in the user's local PC, laptop, or The idea is that the agent is run in the user's local PC, laptop, or
terminal. Authentication data need not be stored on any other terminal.
Authentication data need not be stored on any other
machine, and authentication passphrases never go over the network. machine, and authentication passphrases never go over the network.
However, the connection to the agent is forwarded over SSH However, the connection to the agent is forwarded over SSH
remote logins, and the user can thus use the privileges given by the remote logins, and the user can thus use the privileges given by the
identities anywhere in the network in a secure way. identities anywhere in the network in a secure way.
.Pp .Pp
There are two main ways to get an agent setup: Either you let the agent There are two main ways to get an agent setup:
Either you let the agent
start a new subcommand into which some environment variables are exported, or start a new subcommand into which some environment variables are exported, or
you let the agent print the needed shell commands (either you let the agent print the needed shell commands (either
.Xr sh 1 .Xr sh 1
@ -99,7 +104,8 @@ A unix-domain socket is created
and the name of this socket is stored in the and the name of this socket is stored in the
.Ev SSH_AUTH_SOCK .Ev SSH_AUTH_SOCK
environment environment
variable. The socket is made accessible only to the current user. variable.
The socket is made accessible only to the current user.
This method is easily abused by root or another instance of the same This method is easily abused by root or another instance of the same
user. user.
.Pp .Pp
@ -112,28 +118,30 @@ line terminates.
.Sh FILES .Sh FILES
.Bl -tag -width Ds .Bl -tag -width Ds
.It Pa $HOME/.ssh/identity .It Pa $HOME/.ssh/identity
Contains the RSA authentication identity of the user. This file Contains the RSA authentication identity of the user.
should not be readable by anyone but the user. It is possible to This file should not be readable by anyone but the user.
It is possible to
specify a passphrase when generating the key; that passphrase will be specify a passphrase when generating the key; that passphrase will be
used to encrypt the private part of this file. This file used to encrypt the private part of this file.
is not used by This file is not used by
.Nm .Nm
but is normally added to the agent using but is normally added to the agent using
.Xr ssh-add 1 .Xr ssh-add 1
at login time. at login time.
.It Pa /tmp/ssh-XXXX/agent.<pid> , .It Pa /tmp/ssh-XXXX/agent.<pid> ,
Unix-domain sockets used to contain the connection to the Unix-domain sockets used to contain the connection to the
authentication agent. These sockets should only be readable by the authentication agent.
owner. The sockets should get automatically removed when the agent These sockets should only be readable by the owner.
exits. The sockets should get automatically removed when the agent exits.
.Sh AUTHOR .Sh AUTHOR
Tatu Ylonen <ylo@cs.hut.fi> Tatu Ylonen <ylo@cs.hut.fi>
.Pp .Pp
OpenSSH OpenSSH
is a derivative of the original (free) ssh 1.2.12 release, but with bugs is a derivative of the original (free) ssh 1.2.12 release, but with bugs
removed and newer features re-added. Rapidly after the 1.2.12 release, removed and newer features re-added.
newer versions bore successively more restrictive licenses. This version Rapidly after the 1.2.12 release,
of OpenSSH newer versions bore successively more restrictive licenses.
This version of OpenSSH
.Bl -bullet .Bl -bullet
.It .It
has all components of a restrictive nature (i.e., patents, see has all components of a restrictive nature (i.e., patents, see

62
ssh-keygen.1
View File

@ -9,7 +9,7 @@
.\" .\"
.\" Created: Sat Apr 22 23:55:14 1995 ylo .\" Created: Sat Apr 22 23:55:14 1995 ylo
.\" .\"
.\" $Id: ssh-keygen.1,v 1.9 2000/01/22 08:57:40 damien Exp $ .\" $Id: ssh-keygen.1,v 1.10 2000/03/26 03:04:53 damien Exp $
.\" .\"
.Dd September 25, 1999 .Dd September 25, 1999
.Dt SSH-KEYGEN 1 .Dt SSH-KEYGEN 1
@ -48,27 +48,31 @@ key in
Additionally, the system administrator may use this to generate host keys. Additionally, the system administrator may use this to generate host keys.
.Pp .Pp
Normally this program generates the key and asks for a file in which Normally this program generates the key and asks for a file in which
to store the private key. The public key is stored in a file with the to store the private key.
same name but The public key is stored in a file with the same name but
.Dq .pub .Dq .pub
appended. The program also asks for a appended.
passphrase. The passphrase may be empty to indicate no passphrase The program also asks for a passphrase.
The passphrase may be empty to indicate no passphrase
(host keys must have empty passphrase), or it may be a string of (host keys must have empty passphrase), or it may be a string of
arbitrary length. Good passphrases are 10-30 characters long and are arbitrary length.
Good passphrases are 10-30 characters long and are
not simple sentences or otherwise easily guessable (English not simple sentences or otherwise easily guessable (English
prose has only 1-2 bits of entropy per word, and provides very bad prose has only 1-2 bits of entropy per word, and provides very bad
passphrases). The passphrase can be changed later by using the passphrases).
The passphrase can be changed later by using the
.Fl p .Fl p
option. option.
.Pp .Pp
There is no way to recover a lost passphrase. If the passphrase is There is no way to recover a lost passphrase.
If the passphrase is
lost or forgotten, you will have to generate a new key and copy the lost or forgotten, you will have to generate a new key and copy the
corresponding public key to other machines. corresponding public key to other machines.
.Pp .Pp
There is also a comment field in the key file that is only for There is also a comment field in the key file that is only for
convenience to the user to help identify the key. The comment can convenience to the user to help identify the key.
tell what the key is for, or whatever is useful. The comment is The comment can tell what the key is for, or whatever is useful.
initialized to The comment is initialized to
.Dq user@host .Dq user@host
when the key is created, but can be changed using the when the key is created, but can be changed using the
.Fl c .Fl c
@ -77,10 +81,11 @@ option.
The options are as follows: The options are as follows:
.Bl -tag -width Ds .Bl -tag -width Ds
.It Fl b Ar bits .It Fl b Ar bits
Specifies the number of bits in the key to create. Minimum is 512 Specifies the number of bits in the key to create.
bits. Generally 1024 bits is considered sufficient, and key sizes Minimum is 512 bits.
above that no longer improve security but make things slower. The Generally 1024 bits is considered sufficient, and key sizes
default is 1024 bits. above that no longer improve security but make things slower.
The default is 1024 bits.
.It Fl c .It Fl c
Requests changing the comment in the private and public key files. Requests changing the comment in the private and public key files.
The program will prompt for the file containing the private keys, for The program will prompt for the file containing the private keys, for
@ -91,7 +96,8 @@ Specifies the filename of the key file.
Show fingerprint of specified private or public key file. Show fingerprint of specified private or public key file.
.It Fl p .It Fl p
Requests changing the passphrase of a private key file instead of Requests changing the passphrase of a private key file instead of
creating a new private key. The program will prompt for the file creating a new private key.
The program will prompt for the file
containing the private key, for the old passphrase, and twice for the containing the private key, for the old passphrase, and twice for the
new passphrase. new passphrase.
.It Fl q .It Fl q
@ -110,28 +116,30 @@ Provides the (old) passphrase.
.Sh FILES .Sh FILES
.Bl -tag -width Ds .Bl -tag -width Ds
.It Pa $HOME/.ssh/identity .It Pa $HOME/.ssh/identity
Contains the RSA authentication identity of the user. This file Contains the RSA authentication identity of the user.
should not be readable by anyone but the user. It is possible to This file should not be readable by anyone but the user.
It is possible to
specify a passphrase when generating the key; that passphrase will be specify a passphrase when generating the key; that passphrase will be
used to encrypt the private part of this file using 3DES. This file used to encrypt the private part of this file using 3DES.
is not automatically accessed by This file is not automatically accessed by
.Nm .Nm
but it is offered as the default file for the private key. but it is offered as the default file for the private key.
.It Pa $HOME/.ssh/identity.pub .It Pa $HOME/.ssh/identity.pub
Contains the public key for authentication. The contents of this file Contains the public key for authentication.
should be added to The contents of this file should be added to
.Pa $HOME/.ssh/authorized_keys .Pa $HOME/.ssh/authorized_keys
on all machines on all machines
where you wish to log in using RSA authentication. There is no where you wish to log in using RSA authentication.
need to keep the contents of this file secret. There is no need to keep the contents of this file secret.
.Sh AUTHOR .Sh AUTHOR
Tatu Ylonen <ylo@cs.hut.fi> Tatu Ylonen <ylo@cs.hut.fi>
.Pp .Pp
OpenSSH OpenSSH
is a derivative of the original (free) ssh 1.2.12 release, but with bugs is a derivative of the original (free) ssh 1.2.12 release, but with bugs
removed and newer features re-added. Rapidly after the 1.2.12 release, removed and newer features re-added.
newer versions bore successively more restrictive licenses. This version Rapidly after the 1.2.12 release,
of OpenSSH newer versions bore successively more restrictive licenses.
This version of OpenSSH
.Bl -bullet .Bl -bullet
.It .It
has all components of a restrictive nature (i.e., patents, see has all components of a restrictive nature (i.e., patents, see

34
ssh.1
View File

@ -9,7 +9,7 @@
.\" .\"
.\" Created: Sat Apr 22 21:55:14 1995 ylo .\" Created: Sat Apr 22 21:55:14 1995 ylo
.\" .\"
.\" $Id: ssh.1,v 1.19 2000/03/17 12:40:17 damien Exp $ .\" $Id: ssh.1,v 1.20 2000/03/26 03:04:54 damien Exp $
.\" .\"
.Dd September 25, 1999 .Dd September 25, 1999
.Dt SSH 1 .Dt SSH 1
@ -287,8 +287,8 @@ host key is not known or has changed.
.Sh OPTIONS .Sh OPTIONS
.Bl -tag -width Ds .Bl -tag -width Ds
.It Fl a .It Fl a
Disables forwarding of the authentication agent connection. This may Disables forwarding of the authentication agent connection.
also be specified on a per-host basis in the configuration file. This may also be specified on a per-host basis in the configuration file.
.It Fl c Ar blowfish|3des .It Fl c Ar blowfish|3des
Selects the cipher to use for encrypting the session. Selects the cipher to use for encrypting the session.
.Ar 3des .Ar 3des
@ -342,8 +342,8 @@ It is possible to have multiple
options (and multiple identities specified in options (and multiple identities specified in
configuration files). configuration files).
.It Fl k .It Fl k
Disables forwarding of Kerberos tickets and AFS tokens. This may Disables forwarding of Kerberos tickets and AFS tokens.
also be specified on a per-host basis in the configuration file. This may also be specified on a per-host basis in the configuration file.
.It Fl l Ar login_name .It Fl l Ar login_name
Specifies the user to log in as on the remote machine. Specifies the user to log in as on the remote machine.
This also may be specified on a per-host basis in the configuration file. This also may be specified on a per-host basis in the configuration file.
@ -390,7 +390,7 @@ Causes all warning and diagnostic messages to be suppressed.
Only fatal errors are displayed. Only fatal errors are displayed.
.It Fl t .It Fl t
Force pseudo-tty allocation. Force pseudo-tty allocation.
This can be used to execute arbitary This can be used to execute arbitrary
screen-based programs on a remote machine, which can be very useful, screen-based programs on a remote machine, which can be very useful,
e.g., when implementing menu services. e.g., when implementing menu services.
.It Fl v .It Fl v
@ -514,8 +514,8 @@ The host is the
argument given on the command line (i.e., the name is not converted to argument given on the command line (i.e., the name is not converted to
a canonicalized host name before matching). a canonicalized host name before matching).
.It Cm AFSTokenPassing .It Cm AFSTokenPassing
Specifies whether to pass AFS tokens to remote host. The argument to Specifies whether to pass AFS tokens to remote host.
this keyword must be The argument to this keyword must be
.Dq yes .Dq yes
or or
.Dq no . .Dq no .
@ -534,7 +534,8 @@ If this flag is set to
.Dq yes , .Dq yes ,
ssh will additionally check the host ip address in the ssh will additionally check the host ip address in the
.Pa known_hosts .Pa known_hosts
file. This allows ssh to detect if a host key changed due to DNS spoofing. file.
This allows ssh to detect if a host key changed due to DNS spoofing.
If the option is set to If the option is set to
.Dq no , .Dq no ,
the check will not be executed. the check will not be executed.
@ -657,15 +658,15 @@ To disable keepalives, the value should be set to
.Dq no .Dq no
in both the server and the client configuration files. in both the server and the client configuration files.
.It Cm KerberosAuthentication .It Cm KerberosAuthentication
Specifies whether Kerberos authentication will be used. The argument to Specifies whether Kerberos authentication will be used.
this keyword must be The argument to this keyword must be
.Dq yes .Dq yes
or or
.Dq no . .Dq no .
.It Cm KerberosTgtPassing .It Cm KerberosTgtPassing
Specifies whether a Kerberos TGT will be forwarded to the server. This Specifies whether a Kerberos TGT will be forwarded to the server.
will only work if the Kerberos server is actually an AFS kaserver. The This will only work if the Kerberos server is actually an AFS kaserver.
argument to this keyword must be The argument to this keyword must be
.Dq yes .Dq yes
or or
.Dq no . .Dq no .
@ -684,8 +685,9 @@ The possible values are:
QUIET, FATAL, ERROR, INFO, VERBOSE and DEBUG. QUIET, FATAL, ERROR, INFO, VERBOSE and DEBUG.
The default is INFO. The default is INFO.
.It Cm NumberOfPasswordPrompts .It Cm NumberOfPasswordPrompts
Specifies the number of password prompts before giving up. The Specifies the number of password prompts before giving up.
argument to this keyword must be an integer. Default is 3. The argument to this keyword must be an integer.
Default is 3.
.It Cm PasswordAuthentication .It Cm PasswordAuthentication
Specifies whether to use password authentication. Specifies whether to use password authentication.
The argument to this keyword must be The argument to this keyword must be

13
ssh.c
View File

@ -11,7 +11,7 @@
*/ */
#include "includes.h" #include "includes.h"
RCSID("$Id: ssh.c,v 1.21 2000/03/09 10:27:52 damien Exp $"); RCSID("$Id: ssh.c,v 1.22 2000/03/26 03:04:54 damien Exp $");
#include "xmalloc.h" #include "xmalloc.h"
#include "ssh.h" #include "ssh.h"
@ -181,6 +181,7 @@ main(int ac, char **av)
struct stat st; struct stat st;
struct passwd *pw, pwcopy; struct passwd *pw, pwcopy;
int interactive = 0, dummy; int interactive = 0, dummy;
int have_pty = 0;
uid_t original_effective_uid; uid_t original_effective_uid;
int plen; int plen;
@ -618,9 +619,6 @@ main(int ac, char **av)
if (host_private_key_loaded) if (host_private_key_loaded)
RSA_free(host_private_key); /* Destroys contents safely */ RSA_free(host_private_key); /* Destroys contents safely */
/* Close connection cleanly after attack. */
cipher_attack_detected = packet_disconnect;
/* Enable compression if requested. */ /* Enable compression if requested. */
if (options.compression) { if (options.compression) {
debug("Requesting compression at level %d.", options.compression_level); debug("Requesting compression at level %d.", options.compression_level);
@ -672,9 +670,10 @@ main(int ac, char **av)
/* Read response from the server. */ /* Read response from the server. */
type = packet_read(&plen); type = packet_read(&plen);
if (type == SSH_SMSG_SUCCESS) if (type == SSH_SMSG_SUCCESS) {
interactive = 1; interactive = 1;
else if (type == SSH_SMSG_FAILURE) have_pty = 1;
} else if (type == SSH_SMSG_FAILURE)
log("Warning: Remote host failed or refused to allocate a pseudo tty."); log("Warning: Remote host failed or refused to allocate a pseudo tty.");
else else
packet_disconnect("Protocol error waiting for pty request response."); packet_disconnect("Protocol error waiting for pty request response.");
@ -802,7 +801,7 @@ main(int ac, char **av)
} }
/* Enter the interactive session. */ /* Enter the interactive session. */
exit_status = client_loop(tty_flag, tty_flag ? options.escape_char : -1); exit_status = client_loop(have_pty, tty_flag ? options.escape_char : -1);
/* Close the connection to the remote host. */ /* Close the connection to the remote host. */
packet_close(); packet_close();

36
ssh.h
View File

@ -13,7 +13,7 @@
* *
*/ */
/* RCSID("$Id: ssh.h,v 1.27 2000/03/09 10:27:52 damien Exp $"); */ /* RCSID("$Id: ssh.h,v 1.28 2000/03/26 03:04:54 damien Exp $"); */
#ifndef SSH_H #ifndef SSH_H
#define SSH_H #define SSH_H
@ -338,8 +338,7 @@ int auth_rhosts(struct passwd * pw, const char *client_user);
* its host key. Returns true if authentication succeeds. * its host key. Returns true if authentication succeeds.
*/ */
int int
auth_rhosts_rsa(struct passwd * pw, const char *client_user, auth_rhosts_rsa(struct passwd * pw, const char *client_user, RSA* client_host_key);
BIGNUM * client_host_key_e, BIGNUM * client_host_key_n);
/* /*
* Tries to authenticate the user using password. Returns true if * Tries to authenticate the user using password. Returns true if
@ -387,41 +386,12 @@ int get_remote_port(void);
int get_local_port(void); int get_local_port(void);
/*
* Tries to match the host name (which must be in all lowercase) against the
* comma-separated sequence of subpatterns (each possibly preceded by ! to
* indicate negation). Returns true if there is a positive match; zero
* otherwise.
*/
int match_hostname(const char *host, const char *pattern, unsigned int len);
/*
* Checks whether the given host is already in the list of our known hosts.
* Returns HOST_OK if the host is known and has the specified key, HOST_NEW
* if the host is not known, and HOST_CHANGED if the host is known but used
* to have a different host key. The host must be in all lowercase.
*/
typedef enum {
HOST_OK, HOST_NEW, HOST_CHANGED
} HostStatus;
HostStatus
check_host_in_hostfile(const char *filename, const char *host,
BIGNUM * e, BIGNUM * n, BIGNUM * ke, BIGNUM * kn);
/*
* Appends an entry to the host file. Returns false if the entry could not
* be appended.
*/
int
add_host_to_hostfile(const char *filename, const char *host,
BIGNUM * e, BIGNUM * n);
/* /*
* Performs the RSA authentication challenge-response dialog with the client, * Performs the RSA authentication challenge-response dialog with the client,
* and returns true (non-zero) if the client gave the correct answer to our * and returns true (non-zero) if the client gave the correct answer to our
* challenge; returns zero if the client gives a wrong answer. * challenge; returns zero if the client gives a wrong answer.
*/ */
int auth_rsa_challenge_dialog(BIGNUM * e, BIGNUM * n); int auth_rsa_challenge_dialog(RSA *pk);
/* /*
* Reads a passphrase from /dev/tty with echo turned off. Returns the * Reads a passphrase from /dev/tty with echo turned off. Returns the

72
sshconnect.c
View File

@ -8,15 +8,19 @@
*/ */
#include "includes.h" #include "includes.h"
RCSID("$OpenBSD: sshconnect.c,v 1.57 2000/03/16 20:56:14 markus Exp $"); RCSID("$OpenBSD: sshconnect.c,v 1.58 2000/03/23 22:15:33 markus Exp $");
#ifdef HAVE_OPENSSL #ifdef HAVE_OPENSSL
#include <openssl/bn.h> #include <openssl/rsa.h>
#include <openssl/dsa.h>
#include <openssl/md5.h> #include <openssl/md5.h>
#include <openssl/bn.h>
#endif #endif
#ifdef HAVE_SSL #ifdef HAVE_SSL
#include <ssl/bn.h> #include <ssl/rsa.h>
#include <ssl/dsa.h>
#include <ssl/md5.h> #include <ssl/md5.h>
#include <ssl/bn.h>
#endif #endif
#include "xmalloc.h" #include "xmalloc.h"
@ -29,7 +33,8 @@ RCSID("$OpenBSD: sshconnect.c,v 1.57 2000/03/16 20:56:14 markus Exp $");
#include "uidswap.h" #include "uidswap.h"
#include "compat.h" #include "compat.h"
#include "readconf.h" #include "readconf.h"
#include "fingerprint.h" #include "key.h"
#include "hostfile.h"
/* Session id for the current session. */ /* Session id for the current session. */
unsigned char session_id[16]; unsigned char session_id[16];
@ -1073,9 +1078,9 @@ read_yes_or_no(const char *prompt, int defval)
*/ */
void void
check_host_key(char *host, struct sockaddr *hostaddr, RSA *host_key) check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
{ {
RSA *file_key; Key *file_key;
char *ip = NULL; char *ip = NULL;
char hostline[1000], *hostp; char hostline[1000], *hostp;
HostStatus host_status; HostStatus host_status;
@ -1129,47 +1134,34 @@ check_host_key(char *host, struct sockaddr *hostaddr, RSA *host_key)
* Store the host key from the known host file in here so that we can * Store the host key from the known host file in here so that we can
* compare it with the key for the IP address. * compare it with the key for the IP address.
*/ */
file_key = RSA_new(); file_key = key_new(host_key->type);
file_key->n = BN_new();
file_key->e = BN_new();
/* /*
* Check if the host key is present in the user\'s list of known * Check if the host key is present in the user\'s list of known
* hosts or in the systemwide list. * hosts or in the systemwide list.
*/ */
host_status = check_host_in_hostfile(options.user_hostfile, host, host_status = check_host_in_hostfile(options.user_hostfile, host, host_key, file_key);
host_key->e, host_key->n,
file_key->e, file_key->n);
if (host_status == HOST_NEW) if (host_status == HOST_NEW)
host_status = check_host_in_hostfile(options.system_hostfile, host, host_status = check_host_in_hostfile(options.system_hostfile, host, host_key, file_key);
host_key->e, host_key->n,
file_key->e, file_key->n);
/* /*
* Also perform check for the ip address, skip the check if we are * Also perform check for the ip address, skip the check if we are
* localhost or the hostname was an ip address to begin with * localhost or the hostname was an ip address to begin with
*/ */
if (options.check_host_ip && !local && strcmp(host, ip)) { if (options.check_host_ip && !local && strcmp(host, ip)) {
RSA *ip_key = RSA_new(); Key *ip_key = key_new(host_key->type);
ip_key->n = BN_new(); ip_status = check_host_in_hostfile(options.user_hostfile, ip, host_key, ip_key);
ip_key->e = BN_new();
ip_status = check_host_in_hostfile(options.user_hostfile, ip,
host_key->e, host_key->n,
ip_key->e, ip_key->n);
if (ip_status == HOST_NEW) if (ip_status == HOST_NEW)
ip_status = check_host_in_hostfile(options.system_hostfile, ip, ip_status = check_host_in_hostfile(options.system_hostfile, ip, host_key, ip_key);
host_key->e, host_key->n,
ip_key->e, ip_key->n);
if (host_status == HOST_CHANGED && if (host_status == HOST_CHANGED &&
(ip_status != HOST_CHANGED || (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
(BN_cmp(ip_key->e, file_key->e) || BN_cmp(ip_key->n, file_key->n))))
host_ip_differ = 1; host_ip_differ = 1;
RSA_free(ip_key); key_free(ip_key);
} else } else
ip_status = host_status; ip_status = host_status;
RSA_free(file_key); key_free(file_key);
switch (host_status) { switch (host_status) {
case HOST_OK: case HOST_OK:
@ -1177,8 +1169,7 @@ check_host_key(char *host, struct sockaddr *hostaddr, RSA *host_key)
debug("Host '%.200s' is known and matches the host key.", host); debug("Host '%.200s' is known and matches the host key.", host);
if (options.check_host_ip) { if (options.check_host_ip) {
if (ip_status == HOST_NEW) { if (ip_status == HOST_NEW) {
if (!add_host_to_hostfile(options.user_hostfile, ip, if (!add_host_to_hostfile(options.user_hostfile, ip, host_key))
host_key->e, host_key->n))
log("Failed to add the host key for IP address '%.30s' to the list of known hosts (%.30s).", log("Failed to add the host key for IP address '%.30s' to the list of known hosts (%.30s).",
ip, options.user_hostfile); ip, options.user_hostfile);
else else
@ -1198,12 +1189,12 @@ check_host_key(char *host, struct sockaddr *hostaddr, RSA *host_key)
} else if (options.strict_host_key_checking == 2) { } else if (options.strict_host_key_checking == 2) {
/* The default */ /* The default */
char prompt[1024]; char prompt[1024];
char *fp = fingerprint(host_key->e, host_key->n); char *fp = key_fingerprint(host_key);
snprintf(prompt, sizeof(prompt), snprintf(prompt, sizeof(prompt),
"The authenticity of host '%.200s' can't be established.\n" "The authenticity of host '%.200s' can't be established.\n"
"Key fingerprint is %d %s.\n" "Key fingerprint is %s.\n"
"Are you sure you want to continue connecting (yes/no)? ", "Are you sure you want to continue connecting (yes/no)? ",
host, BN_num_bits(host_key->n), fp); host, fp);
if (!read_yes_or_no(prompt, -1)) if (!read_yes_or_no(prompt, -1))
fatal("Aborted by user!\n"); fatal("Aborted by user!\n");
} }
@ -1214,8 +1205,7 @@ check_host_key(char *host, struct sockaddr *hostaddr, RSA *host_key)
hostp = host; hostp = host;
/* If not in strict mode, add the key automatically to the local known_hosts file. */ /* If not in strict mode, add the key automatically to the local known_hosts file. */
if (!add_host_to_hostfile(options.user_hostfile, hostp, if (!add_host_to_hostfile(options.user_hostfile, hostp, host_key))
host_key->e, host_key->n))
log("Failed to add the host to the list of known hosts (%.500s).", log("Failed to add the host to the list of known hosts (%.500s).",
options.user_hostfile); options.user_hostfile);
else else
@ -1283,6 +1273,14 @@ check_host_key(char *host, struct sockaddr *hostaddr, RSA *host_key)
if (options.check_host_ip) if (options.check_host_ip)
xfree(ip); xfree(ip);
} }
void
check_rsa_host_key(char *host, struct sockaddr *hostaddr, RSA *host_key)
{
Key k;
k.type = KEY_RSA;
k.rsa = host_key;
check_host_key(host, hostaddr, &k);
}
/* /*
* SSH1 key exchange * SSH1 key exchange
@ -1358,7 +1356,7 @@ ssh_kex(char *host, struct sockaddr *hostaddr)
8 + 4 + sum_len + 0 + 4 + 0 + 0 + 4 + 4 + 4, 8 + 4 + sum_len + 0 + 4 + 0 + 0 + 4 + 4 + 4,
SSH_SMSG_PUBLIC_KEY); SSH_SMSG_PUBLIC_KEY);
check_host_key(host, hostaddr, host_key); check_rsa_host_key(host, hostaddr, host_key);
client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN; client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN;
@ -1617,7 +1615,6 @@ ssh_userauth(int host_key_valid, RSA *own_host_key,
fatal("Permission denied."); fatal("Permission denied.");
/* NOTREACHED */ /* NOTREACHED */
} }
/* /*
* Starts a dialog with the server, and authenticates the current user on the * Starts a dialog with the server, and authenticates the current user on the
* server. This does not need any extra privileges. The basic connection * server. This does not need any extra privileges. The basic connection
@ -1648,6 +1645,7 @@ ssh_login(int host_key_valid, RSA *own_host_key, const char *orighost,
ssh_kex(host, hostaddr); ssh_kex(host, hostaddr);
if (supported_authentications == 0) if (supported_authentications == 0)
fatal("supported_authentications == 0."); fatal("supported_authentications == 0.");
/* authenticate user */ /* authenticate user */
ssh_userauth(host_key_valid, own_host_key, original_real_uid, host); ssh_userauth(host_key_valid, own_host_key, original_real_uid, host);
} }

386
sshd.8
View File

@ -9,7 +9,7 @@
.\" .\"
.\" Created: Sat Apr 22 21:55:14 1995 ylo .\" Created: Sat Apr 22 21:55:14 1995 ylo
.\" .\"
.\" $Id: sshd.8,v 1.14 2000/03/17 12:40:18 damien Exp $ .\" $Id: sshd.8,v 1.15 2000/03/26 03:04:55 damien Exp $
.\" .\"
.Dd September 25, 1999 .Dd September 25, 1999
.Dt SSHD 8 .Dt SSHD 8
@ -33,39 +33,48 @@
.Xr ssh 1 . .Xr ssh 1 .
Together these programs replace rlogin and rsh programs, and Together these programs replace rlogin and rsh programs, and
provide secure encrypted communications between two untrusted hosts provide secure encrypted communications between two untrusted hosts
over an insecure network. The programs are intended to be as easy to over an insecure network.
The programs are intended to be as easy to
install and use as possible. install and use as possible.
.Pp .Pp
.Nm .Nm
is the daemon that listens for connections from clients. It is is the daemon that listens for connections from clients.
normally started at boot from It is normally started at boot from
.Pa /etc/rc . .Pa /etc/rc .
It forks a new It forks a new
daemon for each incoming connection. The forked daemons handle daemon for each incoming connection.
The forked daemons handle
key exchange, encryption, authentication, command execution, key exchange, encryption, authentication, command execution,
and data exchange. and data exchange.
.Pp .Pp
.Nm .Nm
works as follows. Each host has a host-specific RSA key works as follows.
(normally 1024 bits) used to identify the host. Additionally, when Each host has a host-specific RSA key
(normally 1024 bits) used to identify the host.
Additionally, when
the daemon starts, it generates a server RSA key (normally 768 bits). the daemon starts, it generates a server RSA key (normally 768 bits).
This key is normally regenerated every hour if it has been used, and This key is normally regenerated every hour if it has been used, and
is never stored on disk. is never stored on disk.
.Pp .Pp
Whenever a client connects the daemon, the daemon sends its host Whenever a client connects the daemon, the daemon sends its host
and server public keys to the client. The client compares the and server public keys to the client.
The client compares the
host key against its own database to verify that it has not changed. host key against its own database to verify that it has not changed.
The client then generates a 256 bit random number. It encrypts this The client then generates a 256 bit random number.
It encrypts this
random number using both the host key and the server key, and sends random number using both the host key and the server key, and sends
the encrypted number to the server. Both sides then start to use this the encrypted number to the server.
Both sides then start to use this
random number as a session key which is used to encrypt all further random number as a session key which is used to encrypt all further
communications in the session. The rest of the session is encrypted communications in the session.
The rest of the session is encrypted
using a conventional cipher, currently Blowfish and 3DES, with 3DES using a conventional cipher, currently Blowfish and 3DES, with 3DES
being is used by default. The client selects the encryption algorithm being is used by default.
The client selects the encryption algorithm
to use from those offered by the server. to use from those offered by the server.
.Pp .Pp
Next, the server and the client enter an authentication dialog. The Next, the server and the client enter an authentication dialog.
client tries to authenticate itself using The client tries to authenticate itself using
.Pa .rhosts .Pa .rhosts
authentication, authentication,
.Pa .rhosts .Pa .rhosts
@ -75,7 +84,8 @@ based authentication.
.Pp .Pp
Rhosts authentication is normally disabled Rhosts authentication is normally disabled
because it is fundamentally insecure, but can be enabled in the server because it is fundamentally insecure, but can be enabled in the server
configuration file if desired. System security is not improved unless configuration file if desired.
System security is not improved unless
.Xr rshd 8 , .Xr rshd 8 ,
.Xr rlogind 8 , .Xr rlogind 8 ,
.Xr rexecd 8 , .Xr rexecd 8 ,
@ -88,13 +98,15 @@ and
into that machine). into that machine).
.Pp .Pp
If the client successfully authenticates itself, a dialog for If the client successfully authenticates itself, a dialog for
preparing the session is entered. At this time the client may request preparing the session is entered.
At this time the client may request
things like allocating a pseudo-tty, forwarding X11 connections, things like allocating a pseudo-tty, forwarding X11 connections,
forwarding TCP/IP connections, or forwarding the authentication agent forwarding TCP/IP connections, or forwarding the authentication agent
connection over the secure channel. connection over the secure channel.
.Pp .Pp
Finally, the client either requests a shell or execution of a command. Finally, the client either requests a shell or execution of a command.
The sides then enter session mode. In this mode, either side may send The sides then enter session mode.
In this mode, either side may send
data at any time, and such data is forwarded to/from the shell or data at any time, and such data is forwarded to/from the shell or
command on the server side, and the user terminal in the client side. command on the server side, and the user terminal in the client side.
.Pp .Pp
@ -104,7 +116,8 @@ the client, and both sides exit.
.Pp .Pp
.Nm .Nm
can be configured using command-line options or a configuration can be configured using command-line options or a configuration
file. Command-line options override values specified in the file.
Command-line options override values specified in the
configuration file. configuration file.
.Pp .Pp
.Nm .Nm
@ -117,20 +130,23 @@ The options are as follows:
Specifies the number of bits in the server key (default 768). Specifies the number of bits in the server key (default 768).
.Pp .Pp
.It Fl d .It Fl d
Debug mode. The server sends verbose debug output to the system Debug mode.
log, and does not put itself in the background. The server also will The server sends verbose debug output to the system
not fork and will only process one connection. This option is only log, and does not put itself in the background.
intended for debugging for the server. The server also will not fork and will only process one connection.
This option is only intended for debugging for the server.
.It Fl f Ar configuration_file .It Fl f Ar configuration_file
Specifies the name of the configuration file. The default is Specifies the name of the configuration file.
The default is
.Pa /etc/sshd_config . .Pa /etc/sshd_config .
.Nm .Nm
refuses to start if there is no configuration file. refuses to start if there is no configuration file.
.It Fl g Ar login_grace_time .It Fl g Ar login_grace_time
Gives the grace time for clients to authenticate themselves (default Gives the grace time for clients to authenticate themselves (default
300 seconds). If the client fails to authenticate the user within 300 seconds).
this many seconds, the server disconnects and exits. A value of zero If the client fails to authenticate the user within
indicates no limit. this many seconds, the server disconnects and exits.
A value of zero indicates no limit.
.It Fl h Ar host_key_file .It Fl h Ar host_key_file
Specifies the file from which the host key is read (default Specifies the file from which the host key is read (default
.Pa /etc/ssh_host_key ) . .Pa /etc/ssh_host_key ) .
@ -145,24 +161,28 @@ is being run from inetd.
.Nm .Nm
is normally not run is normally not run
from inetd because it needs to generate the server key before it can from inetd because it needs to generate the server key before it can
respond to the client, and this may take tens of seconds. Clients respond to the client, and this may take tens of seconds.
would have to wait too long if the key was regenerated every time. Clients would have to wait too long if the key was regenerated every time.
However, with small key sizes (e.g., 512) using However, with small key sizes (e.g., 512) using
.Nm .Nm
from inetd may from inetd may
be feasible. be feasible.
.It Fl k Ar key_gen_time .It Fl k Ar key_gen_time
Specifies how often the server key is regenerated (default 3600 Specifies how often the server key is regenerated (default 3600
seconds, or one hour). The motivation for regenerating the key fairly seconds, or one hour).
The motivation for regenerating the key fairly
often is that the key is not stored anywhere, and after about an hour, often is that the key is not stored anywhere, and after about an hour,
it becomes impossible to recover the key for decrypting intercepted it becomes impossible to recover the key for decrypting intercepted
communications even if the machine is cracked into or physically communications even if the machine is cracked into or physically
seized. A value of zero indicates that the key will never be regenerated. seized.
A value of zero indicates that the key will never be regenerated.
.It Fl p Ar port .It Fl p Ar port
Specifies the port on which the server listens for connections Specifies the port on which the server listens for connections
(default 22). (default 22).
.It Fl q .It Fl q
Quiet mode. Nothing is sent to the system log. Normally the beginning, Quiet mode.
Nothing is sent to the system log.
Normally the beginning,
authentication, and termination of each connection is logged. authentication, and termination of each connection is logged.
.It Fl Q .It Fl Q
Do not print an error message if RSA support is missing. Do not print an error message if RSA support is missing.
@ -188,39 +208,43 @@ reads configuration data from
.Pa /etc/sshd_config .Pa /etc/sshd_config
(or the file specified with (or the file specified with
.Fl f .Fl f
on the command line). The file on the command line).
contains keyword-value pairs, one per line. Lines starting with The file contains keyword-value pairs, one per line.
Lines starting with
.Ql # .Ql #
and empty lines are interpreted as comments. and empty lines are interpreted as comments.
.Pp .Pp
The following keywords are possible. The following keywords are possible.
.Bl -tag -width Ds .Bl -tag -width Ds
.It Cm AFSTokenPassing .It Cm AFSTokenPassing
Specifies whether an AFS token may be forwarded to the server. Default is Specifies whether an AFS token may be forwarded to the server.
Default is
.Dq yes . .Dq yes .
.It Cm AllowGroups .It Cm AllowGroups
This keyword can be followed by a number of group names, separated This keyword can be followed by a number of group names, separated
by spaces. If specified, login is allowed only for users whose primary by spaces.
If specified, login is allowed only for users whose primary
group matches one of the patterns. group matches one of the patterns.
.Ql \&* .Ql \&*
and and
.Ql ? .Ql ?
can be used as can be used as
wildcards in the patterns. Only group names are valid, a numerical group wildcards in the patterns.
id isn't recognized. By default login is allowed regardless of Only group names are valid, a numerical group ID isn't recognized.
the primary group. By default login is allowed regardless of the primary group.
.Pp .Pp
.It Cm AllowUsers .It Cm AllowUsers
This keyword can be followed by a number of user names, separated This keyword can be followed by a number of user names, separated
by spaces. If specified, login is allowed only for users names that by spaces.
If specified, login is allowed only for users names that
match one of the patterns. match one of the patterns.
.Ql \&* .Ql \&*
and and
.Ql ? .Ql ?
can be used as can be used as
wildcards in the patterns. Only user names are valid, a numerical user wildcards in the patterns.
id isn't recognized. By default login is allowed regardless of Only user names are valid, a numerical user ID isn't recognized.
the user name. By default login is allowed regardless of the user name.
.Pp .Pp
.It Cm CheckMail .It Cm CheckMail
Specifies whether Specifies whether
@ -230,27 +254,27 @@ The default is
.Dq no . .Dq no .
.It Cm DenyGroups .It Cm DenyGroups
This keyword can be followed by a number of group names, separated This keyword can be followed by a number of group names, separated
by spaces. Users whose primary group matches one of the patterns by spaces.
Users whose primary group matches one of the patterns
aren't allowed to log in. aren't allowed to log in.
.Ql \&* .Ql \&*
and and
.Ql ? .Ql ?
can be used as can be used as
wildcards in the patterns. Only group names are valid, a numerical group wildcards in the patterns.
id isn't recognized. By default login is allowed regardless of Only group names are valid, a numerical group ID isn't recognized.
the primary group. By default login is allowed regardless of the primary group.
.Pp .Pp
.It Cm DenyUsers .It Cm DenyUsers
This keyword can be followed by a number of user names, separated This keyword can be followed by a number of user names, separated
by spaces. Login is disallowed for user names that match by spaces.
one of the patterns. Login is disallowed for user names that match one of the patterns.
.Ql \&* .Ql \&*
and and
.Ql ? .Ql ?
can be used as can be used as wildcards in the patterns.
wildcards in the patterns. Only user names are valid, a numerical user Only user names are valid, a numerical user ID isn't recognized.
id isn't recognized. By default login is allowed regardless of By default login is allowed regardless of the user name.
the user name.
.It Cm HostKey .It Cm HostKey
Specifies the file containing the private host key (default Specifies the file containing the private host key (default
.Pa /etc/ssh_host_key ) . .Pa /etc/ssh_host_key ) .
@ -266,7 +290,8 @@ files will not be used in authentication.
.Pa /etc/hosts.equiv .Pa /etc/hosts.equiv
and and
.Pa /etc/shosts.equiv .Pa /etc/shosts.equiv
are still used. The default is are still used.
The default is
.Dq yes . .Dq yes .
.It Cm IgnoreUserKnownHosts .It Cm IgnoreUserKnownHosts
Specifies whether Specifies whether
@ -279,10 +304,13 @@ The default is
.Dq no . .Dq no .
.It Cm KeepAlive .It Cm KeepAlive
Specifies whether the system should send keepalive messages to the Specifies whether the system should send keepalive messages to the
other side. If they are sent, death of the connection or crash of one other side.
of the machines will be properly noticed. However, this means that If they are sent, death of the connection or crash of one
of the machines will be properly noticed.
However, this means that
connections will die if the route is down temporarily, and some people connections will die if the route is down temporarily, and some people
find it annoying. On the other hand, if keepalives are not send, find it annoying.
On the other hand, if keepalives are not send,
sessions may hang indefinitely on the server, leaving sessions may hang indefinitely on the server, leaving
.Dq ghost .Dq ghost
users and consuming server resources. users and consuming server resources.
@ -290,25 +318,27 @@ users and consuming server resources.
The default is The default is
.Dq yes .Dq yes
(to send keepalives), and the server will notice (to send keepalives), and the server will notice
if the network goes down or the client host reboots. This avoids if the network goes down or the client host reboots.
infinitely hanging sessions. This avoids infinitely hanging sessions.
.Pp .Pp
To disable keepalives, the value should be set to To disable keepalives, the value should be set to
.Dq no .Dq no
in both the server and the client configuration files. in both the server and the client configuration files.
.It Cm KerberosAuthentication .It Cm KerberosAuthentication
Specifies whether Kerberos authentication is allowed. This can Specifies whether Kerberos authentication is allowed.
be in the form of a Kerberos ticket, or if This can be in the form of a Kerberos ticket, or if
.Cm PasswordAuthentication .Cm PasswordAuthentication
is yes, the password provided by the user will be validated through is yes, the password provided by the user will be validated through
the Kerberos KDC. Default is the Kerberos KDC.
Default is
.Dq yes . .Dq yes .
.It Cm KerberosOrLocalPasswd .It Cm KerberosOrLocalPasswd
If set then if password authentication through Kerberos fails then If set then if password authentication through Kerberos fails then
the password will be validated via any additional local mechanism the password will be validated via any additional local mechanism
such as such as
.Pa /etc/passwd .Pa /etc/passwd
or SecurID. Default is or SecurID.
Default is
.Dq yes . .Dq yes .
.It Cm KerberosTgtPassing .It Cm KerberosTgtPassing
Specifies whether a Kerberos TGT may be forwarded to the server. Specifies whether a Kerberos TGT may be forwarded to the server.
@ -317,15 +347,18 @@ Default is
as this only works when the Kerberos KDC is actually an AFS kaserver. as this only works when the Kerberos KDC is actually an AFS kaserver.
.It Cm KerberosTicketCleanup .It Cm KerberosTicketCleanup
Specifies whether to automatically destroy the user's ticket cache Specifies whether to automatically destroy the user's ticket cache
file on logout. Default is file on logout.
Default is
.Dq yes . .Dq yes .
.It Cm KeyRegenerationInterval .It Cm KeyRegenerationInterval
The server key is automatically regenerated after this many seconds The server key is automatically regenerated after this many seconds
(if it has been used). The purpose of regeneration is to prevent (if it has been used).
The purpose of regeneration is to prevent
decrypting captured sessions by later breaking into the machine and decrypting captured sessions by later breaking into the machine and
stealing the keys. The key is never stored anywhere. If the value is stealing the keys.
0, the key is never regenerated. The default is 3600 The key is never stored anywhere.
(seconds). If the value is 0, the key is never regenerated.
The default is 3600 (seconds).
.It Cm ListenAddress .It Cm ListenAddress
Specifies what local address Specifies what local address
.Nm .Nm
@ -337,7 +370,8 @@ Additionally, the
options must precede this option. options must precede this option.
.It Cm LoginGraceTime .It Cm LoginGraceTime
The server disconnects after this time if the user has not The server disconnects after this time if the user has not
successfully logged in. If the value is 0, there is no time limit. successfully logged in.
If the value is 0, there is no time limit.
The default is 600 (seconds). The default is 600 (seconds).
.It Cm LogLevel .It Cm LogLevel
Gives the verbosity level that is used when logging messages from Gives the verbosity level that is used when logging messages from
@ -353,8 +387,8 @@ The default is
.Dq yes . .Dq yes .
.It Cm PermitEmptyPasswords .It Cm PermitEmptyPasswords
When password authentication is allowed, it specifies whether the When password authentication is allowed, it specifies whether the
server allows login to accounts with empty password strings. The default server allows login to accounts with empty password strings.
is The default is
.Dq no . .Dq no .
.It Cm PermitRootLogin .It Cm PermitRootLogin
Specifies whether the root can log in using Specifies whether the root can log in using
@ -379,24 +413,27 @@ normally not allowed).
.It Cm Port .It Cm Port
Specifies the port number that Specifies the port number that
.Nm .Nm
listens on. The default is 22. listens on.
The default is 22.
Multiple options of this type are permitted. Multiple options of this type are permitted.
.It Cm PrintMotd .It Cm PrintMotd
Specifies whether Specifies whether
.Nm .Nm
should print should print
.Pa /etc/motd .Pa /etc/motd
when a user logs in interactively. (On some systems it is also when a user logs in interactively.
printed by the shell, (On some systems it is also printed by the shell,
.Pa /etc/profile , .Pa /etc/profile ,
or equivalent.) The default is or equivalent.)
The default is
.Dq yes . .Dq yes .
.It Cm RandomSeed .It Cm RandomSeed
Obsolete. Random number generation uses other techniques. Obsolete.
Random number generation uses other techniques.
.It Cm RhostsAuthentication .It Cm RhostsAuthentication
Specifies whether authentication using rhosts or /etc/hosts.equiv Specifies whether authentication using rhosts or /etc/hosts.equiv
files is sufficient. Normally, this method should not be permitted files is sufficient.
because it is insecure. Normally, this method should not be permitted because it is insecure.
.Cm RhostsRSAAuthentication .Cm RhostsRSAAuthentication
should be used should be used
instead, because it performs RSA-based host authentication in addition instead, because it performs RSA-based host authentication in addition
@ -405,18 +442,21 @@ The default is
.Dq no . .Dq no .
.It Cm RhostsRSAAuthentication .It Cm RhostsRSAAuthentication
Specifies whether rhosts or /etc/hosts.equiv authentication together Specifies whether rhosts or /etc/hosts.equiv authentication together
with successful RSA host authentication is allowed. The default is with successful RSA host authentication is allowed.
The default is
.Dq no . .Dq no .
.It Cm RSAAuthentication .It Cm RSAAuthentication
Specifies whether pure RSA authentication is allowed. The default is Specifies whether pure RSA authentication is allowed.
The default is
.Dq yes . .Dq yes .
.It Cm ServerKeyBits .It Cm ServerKeyBits
Defines the number of bits in the server key. The minimum value is Defines the number of bits in the server key.
512, and the default is 768. The minimum value is 512, and the default is 768.
.It Cm SkeyAuthentication .It Cm SkeyAuthentication
Specifies whether Specifies whether
.Xr skey 1 .Xr skey 1
authentication is allowed. The default is authentication is allowed.
The default is
.Dq yes . .Dq yes .
Note that s/key authentication is enabled only if Note that s/key authentication is enabled only if
.Cm PasswordAuthentication .Cm PasswordAuthentication
@ -425,29 +465,34 @@ is allowed, too.
Specifies whether Specifies whether
.Nm .Nm
should check file modes and ownership of the should check file modes and ownership of the
user's files and home directory before accepting login. This user's files and home directory before accepting login.
is normally desirable because novices sometimes accidentally leave their This is normally desirable because novices sometimes accidentally leave their
directory or files world-writable. The default is directory or files world-writable.
The default is
.Dq yes . .Dq yes .
.It Cm SyslogFacility .It Cm SyslogFacility
Gives the facility code that is used when logging messages from Gives the facility code that is used when logging messages from
.Nm sshd . .Nm sshd .
The possible values are: DAEMON, USER, AUTH, LOCAL0, LOCAL1, LOCAL2, The possible values are: DAEMON, USER, AUTH, LOCAL0, LOCAL1, LOCAL2,
LOCAL3, LOCAL4, LOCAL5, LOCAL6, LOCAL7. The default is AUTH. LOCAL3, LOCAL4, LOCAL5, LOCAL6, LOCAL7.
The default is AUTH.
.It Cm UseLogin .It Cm UseLogin
Specifies whether Specifies whether
.Xr login 1 .Xr login 1
is used. The default is is used.
The default is
.Dq no . .Dq no .
.It Cm X11DisplayOffset .It Cm X11DisplayOffset
Specifies the first display number available for Specifies the first display number available for
.Nm sshd Ns 's .Nm sshd Ns 's
X11 forwarding. This prevents X11 forwarding.
This prevents
.Nm .Nm
from interfering with real X11 servers. from interfering with real X11 servers.
The default is 10. The default is 10.
.It Cm X11Forwarding .It Cm X11Forwarding
Specifies whether X11 forwarding is permitted. The default is Specifies whether X11 forwarding is permitted.
The default is
.Dq no . .Dq no .
Note that disabling X11 forwarding does not improve security in any Note that disabling X11 forwarding does not improve security in any
way, as users can always install their own forwarders. way, as users can always install their own forwarders.
@ -489,7 +534,8 @@ If
exists, runs it; else if exists, runs it; else if
.Pa /etc/sshrc .Pa /etc/sshrc
exists, runs exists, runs
it; otherwise runs xauth. The it; otherwise runs xauth.
The
.Dq rc .Dq rc
files are given the X11 files are given the X11
authentication protocol and cookie in standard input. authentication protocol and cookie in standard input.
@ -500,12 +546,15 @@ Runs user's shell or command.
The The
.Pa $HOME/.ssh/authorized_keys .Pa $HOME/.ssh/authorized_keys
file lists the RSA keys that are file lists the RSA keys that are
permitted for RSA authentication. Each line of the file contains one permitted for RSA authentication.
Each line of the file contains one
key (empty lines and lines starting with a key (empty lines and lines starting with a
.Ql # .Ql #
are ignored as are ignored as
comments). Each line consists of the following fields, separated by comments).
spaces: options, bits, exponent, modulus, comment. The options field Each line consists of the following fields, separated by
spaces: options, bits, exponent, modulus, comment.
The options field
is optional; its presence is determined by whether the line starts is optional; its presence is determined by whether the line starts
with a number or not (the option field never starts with a number). with a number or not (the option field never starts with a number).
The bits, exponent, modulus and comment fields give the RSA key; the The bits, exponent, modulus and comment fields give the RSA key; the
@ -513,47 +562,58 @@ comment field is not used for anything (but may be convenient for the
user to identify the key). user to identify the key).
.Pp .Pp
Note that lines in this file are usually several hundred bytes long Note that lines in this file are usually several hundred bytes long
(because of the size of the RSA key modulus). You don't want to type (because of the size of the RSA key modulus).
them in; instead, copy the You don't want to type them in; instead, copy the
.Pa identity.pub .Pa identity.pub
file and edit it. file and edit it.
.Pp .Pp
The options (if present) consists of comma-separated option The options (if present) consists of comma-separated option
specifications. No spaces are permitted, except within double quotes. specifications.
No spaces are permitted, except within double quotes.
The following option specifications are supported: The following option specifications are supported:
.Bl -tag -width Ds .Bl -tag -width Ds
.It Cm from="pattern-list" .It Cm from="pattern-list"
Specifies that in addition to RSA authentication, the canonical name Specifies that in addition to RSA authentication, the canonical name
of the remote host must be present in the comma-separated list of of the remote host must be present in the comma-separated list of
patterns ('*' and '?' serve as wildcards). The list may also contain patterns
patterns negated by prefixing them with '!'; if the canonical host .Pf ( Ql *
name matches a negated pattern, the key is not accepted. The purpose and
.Ql ?
serve as wildcards).
The list may also contain
patterns negated by prefixing them with
.Ql ! ;
if the canonical host name matches a negated pattern, the key is not accepted.
The purpose
of this option is to optionally increase security: RSA authentication of this option is to optionally increase security: RSA authentication
by itself does not trust the network or name servers or anything (but by itself does not trust the network or name servers or anything (but
the key); however, if somebody somehow steals the key, the key the key); however, if somebody somehow steals the key, the key
permits an intruder to log in from anywhere in the world. This permits an intruder to log in from anywhere in the world.
additional option makes using a stolen key more difficult (name This additional option makes using a stolen key more difficult (name
servers and/or routers would have to be compromised in addition to servers and/or routers would have to be compromised in addition to
just the key). just the key).
.It Cm command="command" .It Cm command="command"
Specifies that the command is executed whenever this key is used for Specifies that the command is executed whenever this key is used for
authentication. The command supplied by the user (if any) is ignored. authentication.
The command supplied by the user (if any) is ignored.
The command is run on a pty if the connection requests a pty; The command is run on a pty if the connection requests a pty;
otherwise it is run without a tty. A quote may be included in the otherwise it is run without a tty.
command by quoting it with a backslash. This option might be useful A quote may be included in the command by quoting it with a backslash.
to restrict certain RSA keys to perform just a specific operation. An This option might be useful
example might be a key that permits remote backups but nothing to restrict certain RSA keys to perform just a specific operation.
else. Notice that the client may specify TCP/IP and/or X11 An example might be a key that permits remote backups but nothing else.
Notice that the client may specify TCP/IP and/or X11
forwardings unless they are explicitly prohibited. forwardings unless they are explicitly prohibited.
.It Cm environment="NAME=value" .It Cm environment="NAME=value"
Specifies that the string is to be added to the environment when Specifies that the string is to be added to the environment when
logging in using this key. Environment variables set this way logging in using this key.
override other default environment values. Multiple options of this Environment variables set this way
type are permitted. override other default environment values.
Multiple options of this type are permitted.
.It Cm no-port-forwarding .It Cm no-port-forwarding
Forbids TCP/IP forwarding when this key is used for authentication. Forbids TCP/IP forwarding when this key is used for authentication.
Any port forward requests by the client will return an error. This Any port forward requests by the client will return an error.
might be used, e.g., in connection with the This might be used, e.g., in connection with the
.Cm command .Cm command
option. option.
.It Cm no-X11-forwarding .It Cm no-X11-forwarding
@ -576,19 +636,21 @@ The
.Pa /etc/ssh_known_hosts .Pa /etc/ssh_known_hosts
and and
.Pa $HOME/.ssh/known_hosts .Pa $HOME/.ssh/known_hosts
files contain host public keys for all known hosts. The global file should files contain host public keys for all known hosts.
be prepared by the admistrator (optional), and the per-user file is The global file should
be prepared by the administrator (optional), and the per-user file is
maintained automatically: whenever the user connects an unknown host maintained automatically: whenever the user connects an unknown host
its key is added to the per-user file. its key is added to the per-user file.
.Pp .Pp
Each line in these files contains the following fields: hostnames, Each line in these files contains the following fields: hostnames,
bits, exponent, modulus, comment. The fields are separated by spaces. bits, exponent, modulus, comment.
The fields are separated by spaces.
.Pp .Pp
Hostnames is a comma-separated list of patterns ('*' and '?' act as Hostnames is a comma-separated list of patterns ('*' and '?' act as
wildcards); each pattern in turn is matched against the canonical host wildcards); each pattern in turn is matched against the canonical host
name (when authenticating a client) or against the user-supplied name (when authenticating a client) or against the user-supplied
name (when authenticating a server). A pattern may also be preceded name (when authenticating a server).
by A pattern may also be preceded by
.Ql ! .Ql !
to indicate negation: if the host name matches a negated to indicate negation: if the host name matches a negated
pattern, it is not accepted (by that line) even if it matched another pattern, it is not accepted (by that line) even if it matched another
@ -604,10 +666,13 @@ Lines starting with
and empty lines are ignored as comments. and empty lines are ignored as comments.
.Pp .Pp
When performing host authentication, authentication is accepted if any When performing host authentication, authentication is accepted if any
matching line has the proper key. It is thus permissible (but not matching line has the proper key.
It is thus permissible (but not
recommended) to have several lines or different host keys for the same recommended) to have several lines or different host keys for the same
names. This will inevitably happen when short forms of host names names.
from different domains are put in the file. It is possible This will inevitably happen when short forms of host names
from different domains are put in the file.
It is possible
that the files contain conflicting information; authentication is that the files contain conflicting information; authentication is
accepted if valid information can be found from either file. accepted if valid information can be found from either file.
.Pp .Pp
@ -636,7 +701,9 @@ does not start if this file is group/world-accessible.
.It Pa /etc/ssh_host_key.pub .It Pa /etc/ssh_host_key.pub
Contains the public part of the host key. Contains the public part of the host key.
This file should be world-readable but writable only by This file should be world-readable but writable only by
root. Its contents should match the private part. This file is not root.
Its contents should match the private part.
This file is not
really used for anything; it is only provided for the convenience of really used for anything; it is only provided for the convenience of
the user so its contents can be copied to known hosts files. the user so its contents can be copied to known hosts files.
These two files are created using These two files are created using
@ -646,21 +713,22 @@ Contains the process ID of the
.Nm .Nm
listening for connections (if there are several daemons running listening for connections (if there are several daemons running
concurrently for different ports, this contains the pid of the one concurrently for different ports, this contains the pid of the one
started last). The contents of this file are not sensitive; it can be started last).
world-readable. The contents of this file are not sensitive; it can be world-readable.
.It Pa $HOME/.ssh/authorized_keys .It Pa $HOME/.ssh/authorized_keys
Lists the RSA keys that can be used to log into the user's account. Lists the RSA keys that can be used to log into the user's account.
This file must be readable by root (which may on some machines imply This file must be readable by root (which may on some machines imply
it being world-readable if the user's home directory resides on an NFS it being world-readable if the user's home directory resides on an NFS
volume). It is recommended that it not be accessible by others. The volume).
format of this file is described above. It is recommended that it not be accessible by others.
The format of this file is described above.
.It Pa "/etc/ssh_known_hosts" and "$HOME/.ssh/known_hosts" .It Pa "/etc/ssh_known_hosts" and "$HOME/.ssh/known_hosts"
These files are consulted when using rhosts with RSA host These files are consulted when using rhosts with RSA host
authentication to check the public key of the host. The key must be authentication to check the public key of the host.
listed in one of these files to be accepted. The key must be listed in one of these files to be accepted.
The client uses the same files The client uses the same files
to verify that the remote host is the one we intended to to verify that the remote host is the one we intended to connect.
connect. These files should be writable only by root/the owner. These files should be writable only by root/the owner.
.Pa /etc/ssh_known_hosts .Pa /etc/ssh_known_hosts
should be world-readable, and should be world-readable, and
.Pa $HOME/.ssh/known_hosts .Pa $HOME/.ssh/known_hosts
@ -668,9 +736,11 @@ can but need not be world-readable.
.It Pa /etc/nologin .It Pa /etc/nologin
If this file exists, If this file exists,
.Nm .Nm
refuses to let anyone except root log in. The contents of the file refuses to let anyone except root log in.
The contents of the file
are displayed to anyone trying to log in, and non-root connections are are displayed to anyone trying to log in, and non-root connections are
refused. The file should be world-readable. refused.
The file should be world-readable.
.It Pa /etc/hosts.allow, /etc/hosts.deny .It Pa /etc/hosts.allow, /etc/hosts.deny
If compiled with If compiled with
.Sy LIBWRAP .Sy LIBWRAP
@ -678,13 +748,16 @@ support, tcp-wrappers access controls may be defined here as described in
.Xr hosts_access 5 . .Xr hosts_access 5 .
.It Pa $HOME/.rhosts .It Pa $HOME/.rhosts
This file contains host-username pairs, separated by a space, one per This file contains host-username pairs, separated by a space, one per
line. The given user on the corresponding host is permitted to log in line.
without password. The same file is used by rlogind and rshd. The given user on the corresponding host is permitted to log in
without password.
The same file is used by rlogind and rshd.
The file must The file must
be writable only by the user; it is recommended that it not be be writable only by the user; it is recommended that it not be
accessible by others. accessible by others.
.Pp .Pp
If is also possible to use netgroups in the file. Either host or user If is also possible to use netgroups in the file.
Either host or user
name may be of the form +@groupname to specify all hosts or all users name may be of the form +@groupname to specify all hosts or all users
in the group. in the group.
.It Pa $HOME/.shosts .It Pa $HOME/.shosts
@ -696,21 +769,26 @@ not used by rlogin and rshd, so using this permits access using SSH only.
.Pa /etc/hosts.equiv .Pa /etc/hosts.equiv
This file is used during This file is used during
.Pa .rhosts .Pa .rhosts
authentication. In the authentication.
simplest form, this file contains host names, one per line. Users on In the simplest form, this file contains host names, one per line.
Users on
those hosts are permitted to log in without a password, provided they those hosts are permitted to log in without a password, provided they
have the same user name on both machines. The host name may also be have the same user name on both machines.
The host name may also be
followed by a user name; such users are permitted to log in as followed by a user name; such users are permitted to log in as
.Em any .Em any
user on this machine (except root). Additionally, the syntax user on this machine (except root).
Additionally, the syntax
.Dq +@group .Dq +@group
can be used to specify netgroups. Negated entries start with can be used to specify netgroups.
Negated entries start with
.Ql \&- . .Ql \&- .
.Pp .Pp
If the client host/user is successfully matched in this file, login is If the client host/user is successfully matched in this file, login is
automatically permitted provided the client and server user names are the automatically permitted provided the client and server user names are the
same. Additionally, successful RSA host authentication is normally same.
required. This file must be writable only by root; it is recommended Additionally, successful RSA host authentication is normally required.
This file must be writable only by root; it is recommended
that it be world-readable. that it be world-readable.
.Pp .Pp
.Sy "Warning: It is almost never a good idea to use user names in" .Sy "Warning: It is almost never a good idea to use user names in"
@ -718,8 +796,9 @@ that it be world-readable.
Beware that it really means that the named user(s) can log in as Beware that it really means that the named user(s) can log in as
.Em anybody , .Em anybody ,
which includes bin, daemon, adm, and other accounts that own critical which includes bin, daemon, adm, and other accounts that own critical
binaries and directories. Using a user name practically grants the binaries and directories.
user root access. The only valid use for user names that I can think Using a user name practically grants the user root access.
The only valid use for user names that I can think
of is in negative entries. of is in negative entries.
.Pp .Pp
Note that this warning also applies to rsh/rlogin. Note that this warning also applies to rsh/rlogin.
@ -729,18 +808,20 @@ This is processed exactly as
However, this file may be useful in environments that want to run both However, this file may be useful in environments that want to run both
rsh/rlogin and ssh. rsh/rlogin and ssh.
.It Pa $HOME/.ssh/environment .It Pa $HOME/.ssh/environment
This file is read into the environment at login (if it exists). It This file is read into the environment at login (if it exists).
can only contain empty lines, comment lines (that start with It can only contain empty lines, comment lines (that start with
.Ql # ) , .Ql # ) ,
and assignment lines of the form name=value. The file should be writable and assignment lines of the form name=value.
The file should be writable
only by the user; it need not be readable by anyone else. only by the user; it need not be readable by anyone else.
.It Pa $HOME/.ssh/rc .It Pa $HOME/.ssh/rc
If this file exists, it is run with /bin/sh after reading the If this file exists, it is run with /bin/sh after reading the
environment files but before starting the user's shell or command. If environment files but before starting the user's shell or command.
X11 spoofing is in use, this will receive the "proto cookie" pair in If X11 spoofing is in use, this will receive the "proto cookie" pair in
standard input (and standard input (and
.Ev DISPLAY .Ev DISPLAY
in environment). This must call in environment).
This must call
.Xr xauth 1 .Xr xauth 1
in that case. in that case.
.Pp .Pp
@ -763,12 +844,13 @@ readable by anyone else.
Like Like
.Pa $HOME/.ssh/rc . .Pa $HOME/.ssh/rc .
This can be used to specify This can be used to specify
machine-specific login-time initializations globally. This file machine-specific login-time initializations globally.
should be writable only by root, and should be world-readable. This file should be writable only by root, and should be world-readable.
.Sh AUTHOR .Sh AUTHOR
OpenSSH OpenSSH
is a derivative of the original (free) ssh 1.2.12 release by Tatu Ylonen, is a derivative of the original (free) ssh 1.2.12 release by Tatu Ylonen,
but with bugs removed and newer features re-added. Rapidly after the but with bugs removed and newer features re-added.
Rapidly after the
1.2.12 release, newer versions of the original ssh bore successively 1.2.12 release, newer versions of the original ssh bore successively
more restrictive licenses, and thus demand for a free version was born. more restrictive licenses, and thus demand for a free version was born.
This version of OpenSSH This version of OpenSSH

30
sshd.c
View File

@ -11,7 +11,7 @@
*/ */
#include "includes.h" #include "includes.h"
RCSID("$OpenBSD: sshd.c,v 1.92 2000/03/16 20:56:15 markus Exp $"); RCSID("$OpenBSD: sshd.c,v 1.94 2000/03/23 22:15:34 markus Exp $");
#include "xmalloc.h" #include "xmalloc.h"
#include "rsa.h" #include "rsa.h"
@ -516,9 +516,6 @@ main(int ac, char **av)
unmounted if desired. */ unmounted if desired. */
chdir("/"); chdir("/");
/* Close connection cleanly after attack. */
cipher_attack_detected = packet_disconnect;
/* Start listening for a socket, unless started from inetd. */ /* Start listening for a socket, unless started from inetd. */
if (inetd_flag) { if (inetd_flag) {
int s1, s2; int s1, s2;
@ -1301,7 +1298,7 @@ do_authloop(struct passwd * pw)
{ {
int attempt = 0; int attempt = 0;
unsigned int bits; unsigned int bits;
BIGNUM *client_host_key_e, *client_host_key_n; RSA *client_host_key;
BIGNUM *n; BIGNUM *n;
char *client_user = NULL, *password = NULL; char *client_user = NULL, *password = NULL;
char user[1024]; char user[1024];
@ -1417,21 +1414,24 @@ do_authloop(struct passwd * pw)
client_user = packet_get_string(&ulen); client_user = packet_get_string(&ulen);
/* Get the client host key. */ /* Get the client host key. */
client_host_key_e = BN_new(); client_host_key = RSA_new();
client_host_key_n = BN_new(); if (client_host_key == NULL)
fatal("RSA_new failed");
client_host_key->e = BN_new();
client_host_key->n = BN_new();
if (client_host_key->e == NULL || client_host_key->n == NULL)
fatal("BN_new failed");
bits = packet_get_int(); bits = packet_get_int();
packet_get_bignum(client_host_key_e, &elen); packet_get_bignum(client_host_key->e, &elen);
packet_get_bignum(client_host_key_n, &nlen); packet_get_bignum(client_host_key->n, &nlen);
if (bits != BN_num_bits(client_host_key_n)) if (bits != BN_num_bits(client_host_key->n))
error("Warning: keysize mismatch for client_host_key: " error("Warning: keysize mismatch for client_host_key: "
"actual %d, announced %d", BN_num_bits(client_host_key_n), bits); "actual %d, announced %d", BN_num_bits(client_host_key->n), bits);
packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type); packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type);
authenticated = auth_rhosts_rsa(pw, client_user, authenticated = auth_rhosts_rsa(pw, client_user, client_host_key);
client_host_key_e, client_host_key_n); RSA_free(client_host_key);
BN_clear_free(client_host_key_e);
BN_clear_free(client_host_key_n);
snprintf(user, sizeof user, " ruser %s", client_user); snprintf(user, sizeof user, " ruser %s", client_user);
break; break;