tyler.durden/openssh-portable
1
0
Fork 0
mirror of https://github.com/PowerShell/openssh-portable.git synced 2025-07-27 15:54:22 +02:00
Code Issues Packages Projects Releases Wiki Activity

upstream: split the low-level file handling functions out from

Browse Source 
auth2-pubkey.c

Put them in a new auth2-pubkeyfile.c to make it easier to refer to them
(e.g. in unit/fuzz tests) without having to refer to everything else
pubkey auth brings in.

ok dtucker@

OpenBSD-Commit-ID: 3fdca2c61ad97dc1b8d4a7346816f83dc4ce2217
This commit is contained in:
djm@openbsd.org 2022-05-27 05:02:46 +00:00 committed by Damien Miller
parent 3b0b142d2a
commit c83d8c4d6f
5 changed files with 465 additions and 402 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Makefile.in
View File

@ -123,7 +123,7 @@ SSHDOBJS=sshd.o auth-rhosts.o auth-passwd.o \
auth.o auth2.o auth-options.o session.o \ auth.o auth2.o auth-options.o session.o \
auth2-chall.o groupaccess.o \ auth2-chall.o groupaccess.o \
auth-bsdauth.o auth2-hostbased.o auth2-kbdint.o \ auth-bsdauth.o auth2-hostbased.o auth2-kbdint.o \
auth2-none.o auth2-passwd.o auth2-pubkey.o \ auth2-none.o auth2-passwd.o auth2-pubkey.o auth2-pubkeyfile.o \
monitor.o monitor_wrap.o auth-krb5.o \ monitor.o monitor_wrap.o auth-krb5.o \
auth2-gss.o gss-serv.o gss-serv-krb5.o \ auth2-gss.o gss-serv.o gss-serv-krb5.o \
loginrec.o auth-pam.o auth-shadow.o auth-sia.o \ loginrec.o auth-pam.o auth-shadow.o auth-sia.o \

94
auth.c
View File

@ -1,4 +1,4 @@
/* $OpenBSD: auth.c,v 1.156 2022/05/27 05:01:25 djm Exp $ */ /* $OpenBSD: auth.c,v 1.157 2022/05/27 05:02:46 djm Exp $ */
/* /*
* Copyright (c) 2000 Markus Friedl. All rights reserved. * Copyright (c) 2000 Markus Friedl. All rights reserved.
* *
@ -912,95 +912,3 @@ auth_restrict_session(struct ssh *ssh)
fatal_f("failed to restrict session"); fatal_f("failed to restrict session");
sshauthopt_free(restricted); sshauthopt_free(restricted);
} }
int
auth_authorise_keyopts(struct passwd *pw, struct sshauthopt *opts,
int allow_cert_authority, const char *remote_ip, const char *remote_host,
const char *loc)
{
time_t now = time(NULL);
char buf[64];
/*
* Check keys/principals file expiry time.
* NB. validity interval in certificate is handled elsewhere.
*/
if (opts->valid_before && now > 0 &&
opts->valid_before < (uint64_t)now) {
format_absolute_time(opts->valid_before, buf, sizeof(buf));
debug("%s: entry expired at %s", loc, buf);
auth_debug_add("%s: entry expired at %s", loc, buf);
return -1;
}
/* Consistency checks */
if (opts->cert_principals != NULL && !opts->cert_authority) {
debug("%s: principals on non-CA key", loc);
auth_debug_add("%s: principals on non-CA key", loc);
/* deny access */
return -1;
}
/* cert-authority flag isn't valid in authorized_principals files */
if (!allow_cert_authority && opts->cert_authority) {
debug("%s: cert-authority flag invalid here", loc);
auth_debug_add("%s: cert-authority flag invalid here", loc);
/* deny access */
return -1;
}
/* Perform from= checks */
if (opts->required_from_host_keys != NULL) {
switch (match_host_and_ip(remote_host, remote_ip,
opts->required_from_host_keys )) {
case 1:
/* Host name matches. */
break;
case -1:
default:
debug("%s: invalid from criteria", loc);
auth_debug_add("%s: invalid from criteria", loc);
/* FALLTHROUGH */
case 0:
logit("%s: Authentication tried for %.100s with "
"correct key but not from a permitted "
"host (host=%.200s, ip=%.200s, required=%.200s).",
loc, pw->pw_name, remote_host, remote_ip,
opts->required_from_host_keys);
auth_debug_add("%s: Your host '%.200s' is not "
"permitted to use this key for login.",
loc, remote_host);
/* deny access */
return -1;
}
}
/* Check source-address restriction from certificate */
if (opts->required_from_host_cert != NULL) {
switch (addr_match_cidr_list(remote_ip,
opts->required_from_host_cert)) {
case 1:
/* accepted */
break;
case -1:
default:
/* invalid */
error("%s: Certificate source-address invalid", loc);
/* FALLTHROUGH */
case 0:
logit("%s: Authentication tried for %.100s with valid "
"certificate but not from a permitted source "
"address (%.200s).", loc, pw->pw_name, remote_ip);
auth_debug_add("%s: Your address '%.200s' is not "
"permitted to use this certificate for login.",
loc, remote_ip);
return -1;
}
}
/*
*
* XXX this is spammy. We should report remotely only for keys
* that are successful in actual auth attempts, and not PK_OK
* tests.
*/
auth_log_authopts(loc, opts, 1);
return 0;
}

18
auth.h
View File

@ -1,4 +1,4 @@
/* $OpenBSD: auth.h,v 1.103 2022/05/27 05:01:25 djm Exp $ */ /* $OpenBSD: auth.h,v 1.104 2022/05/27 05:02:46 djm Exp $ */
/* /*
* Copyright (c) 2000 Markus Friedl. All rights reserved. * Copyright (c) 2000 Markus Friedl. All rights reserved.
@ -29,6 +29,7 @@
#define AUTH_H #define AUTH_H
#include <signal.h> #include <signal.h>
#include <stdio.h>
#ifdef HAVE_LOGIN_CAP #ifdef HAVE_LOGIN_CAP
#include <login_cap.h> #include <login_cap.h>
@ -44,6 +45,7 @@ struct passwd;
struct ssh; struct ssh;
struct sshbuf; struct sshbuf;
struct sshkey; struct sshkey;
struct sshkey_cert;
struct sshauthopt; struct sshauthopt;
typedef struct Authctxt Authctxt; typedef struct Authctxt Authctxt;
@ -214,8 +216,6 @@ int sshd_hostkey_sign(struct ssh *, struct sshkey *, struct sshkey *,
const struct sshauthopt *auth_options(struct ssh *); const struct sshauthopt *auth_options(struct ssh *);
int auth_activate_options(struct ssh *, struct sshauthopt *); int auth_activate_options(struct ssh *, struct sshauthopt *);
void auth_restrict_session(struct ssh *); void auth_restrict_session(struct ssh *);
int auth_authorise_keyopts(struct passwd *pw, struct sshauthopt *, int,
const char *, const char *, const char *);
void auth_log_authopts(const char *, const struct sshauthopt *, int); void auth_log_authopts(const char *, const struct sshauthopt *, int);
/* debug messages during authentication */ /* debug messages during authentication */
@ -226,6 +226,18 @@ void auth_debug_reset(void);
struct passwd *fakepw(void); struct passwd *fakepw(void);
/* auth2-pubkeyfile.c */
int auth_authorise_keyopts(struct passwd *, struct sshauthopt *, int,
const char *, const char *, const char *);
int auth_check_principals_line(char *, const struct sshkey_cert *,
const char *, struct sshauthopt **);
int auth_process_principals(FILE *, const char *,
const struct sshkey_cert *, struct sshauthopt **);
int auth_check_authkey_line(struct passwd *, struct sshkey *,
char *, const char *, const char *, const char *, struct sshauthopt **);
int auth_check_authkeys_file(struct passwd *, FILE *, char *,
struct sshkey *, const char *, const char *, struct sshauthopt **);
int sys_auth_passwd(struct ssh *, const char *); int sys_auth_passwd(struct ssh *, const char *);
#if defined(KRB5) && !defined(HEIMDAL) #if defined(KRB5) && !defined(HEIMDAL)

311
auth2-pubkey.c
View File

@ -1,6 +1,7 @@
/* $OpenBSD: auth2-pubkey.c,v 1.114 2022/05/27 05:01:25 djm Exp $ */ /* $OpenBSD: auth2-pubkey.c,v 1.115 2022/05/27 05:02:46 djm Exp $ */
/* /*
* Copyright (c) 2000 Markus Friedl. All rights reserved. * Copyright (c) 2000 Markus Friedl. All rights reserved.
* Copyright (c) 2010 Damien Miller. All rights reserved.
* *
* Redistribution and use in source and binary forms, with or without * Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions * modification, are permitted provided that the following conditions
@ -26,11 +27,9 @@
#include "includes.h" #include "includes.h"
#include <sys/types.h> #include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h> #include <stdlib.h>
#include <errno.h> #include <errno.h>
#include <fcntl.h>
#ifdef HAVE_PATHS_H #ifdef HAVE_PATHS_H
# include <paths.h> # include <paths.h>
#endif #endif
@ -67,7 +66,6 @@
#include "authfile.h" #include "authfile.h"
#include "match.h" #include "match.h"
#include "ssherr.h" #include "ssherr.h"
#include "kex.h"
#include "channels.h" /* XXX for session.h */ #include "channels.h" /* XXX for session.h */
#include "session.h" /* XXX for child_set_env(); refactor? */ #include "session.h" /* XXX for child_set_env(); refactor? */
#include "sk-api.h" #include "sk-api.h"
@ -321,120 +319,6 @@ done:
return authenticated; return authenticated;
} }
static int
match_principals_option(const char *principal_list, struct sshkey_cert *cert)
{
char *result;
u_int i;
/* XXX percent_expand() sequences for authorized_principals? */
for (i = 0; i < cert->nprincipals; i++) {
if ((result = match_list(cert->principals[i],
principal_list, NULL)) != NULL) {
debug3("matched principal from key options \"%.100s\"",
result);
free(result);
return 1;
}
}
return 0;
}
/*
* Process a single authorized_principals format line. Returns 0 and sets
* authoptsp is principal is authorised, -1 otherwise. "loc" is used as a
* log preamble for file/line information.
*/
static int
check_principals_line(char *cp, const struct sshkey_cert *cert,
const char *loc, struct sshauthopt **authoptsp)
{
u_int i, found = 0;
char *ep, *line_opts;
const char *reason = NULL;
struct sshauthopt *opts = NULL;
if (authoptsp != NULL)
*authoptsp = NULL;
/* Trim trailing whitespace. */
ep = cp + strlen(cp) - 1;
while (ep > cp && (*ep == '\n' || *ep == ' ' || *ep == '\t'))
*ep-- = '\0';
/*
* If the line has internal whitespace then assume it has
* key options.
*/
line_opts = NULL;
if ((ep = strrchr(cp, ' ')) != NULL ||
(ep = strrchr(cp, '\t')) != NULL) {
for (; *ep == ' ' || *ep == '\t'; ep++)
;
line_opts = cp;
cp = ep;
}
if ((opts = sshauthopt_parse(line_opts, &reason)) == NULL) {
debug("%s: bad principals options: %s", loc, reason);
auth_debug_add("%s: bad principals options: %s", loc, reason);
return -1;
}
/* Check principals in cert against those on line */
for (i = 0; i < cert->nprincipals; i++) {
if (strcmp(cp, cert->principals[i]) != 0)
continue;
debug3("%s: matched principal \"%.100s\"",
loc, cert->principals[i]);
found = 1;
}
if (found && authoptsp != NULL) {
*authoptsp = opts;
opts = NULL;
}
sshauthopt_free(opts);
return found ? 0 : -1;
}
static int
process_principals(FILE *f, const char *file,
const struct sshkey_cert *cert, struct sshauthopt **authoptsp)
{
char loc[256], *line = NULL, *cp, *ep;
size_t linesize = 0;
u_long linenum = 0, nonblank = 0;
u_int found_principal = 0;
if (authoptsp != NULL)
*authoptsp = NULL;
while (getline(&line, &linesize, f) != -1) {
linenum++;
/* Always consume entire input */
if (found_principal)
continue;
/* Skip leading whitespace. */
for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
;
/* Skip blank and comment lines. */
if ((ep = strchr(cp, '#')) != NULL)
*ep = '\0';
if (!*cp || *cp == '\n')
continue;
nonblank++;
snprintf(loc, sizeof(loc), "%.200s:%lu", file, linenum);
if (check_principals_line(cp, cert, loc, authoptsp) == 0)
found_principal = 1;
}
debug2_f("%s: processed %lu/%lu lines", file, nonblank, linenum);
free(line);
return found_principal;
}
/* XXX remove pw args here and elsewhere once ssh->authctxt is guaranteed */
static int static int
match_principals_file(struct passwd *pw, char *file, match_principals_file(struct passwd *pw, char *file,
struct sshkey_cert *cert, struct sshauthopt **authoptsp) struct sshkey_cert *cert, struct sshauthopt **authoptsp)
@ -451,7 +335,7 @@ match_principals_file(struct passwd *pw, char *file,
restore_uid(); restore_uid();
return 0; return 0;
} }
success = process_principals(f, file, cert, authoptsp); success = auth_process_principals(f, file, cert, authoptsp);
fclose(f); fclose(f);
restore_uid(); restore_uid();
return success; return success;
@ -567,7 +451,7 @@ match_principals_command(struct passwd *user_pw,
uid_swapped = 1; uid_swapped = 1;
temporarily_use_uid(runas_pw); temporarily_use_uid(runas_pw);
ok = process_principals(f, "(command)", cert, authoptsp); ok = auth_process_principals(f, "(command)", cert, authoptsp);
fclose(f); fclose(f);
f = NULL; f = NULL;
@ -595,189 +479,6 @@ match_principals_command(struct passwd *user_pw,
return found_principal; return found_principal;
} }
/*
* Check a single line of an authorized_keys-format file. Returns 0 if key
* matches, -1 otherwise. Will return key/cert options via *authoptsp
* on success. "loc" is used as file/line location in log messages.
*/
static int
check_authkey_line(struct passwd *pw, struct sshkey *key,
char *cp, const char *remote_ip, const char *remote_host, const char *loc,
struct sshauthopt **authoptsp)
{
int want_keytype = sshkey_is_cert(key) ? KEY_UNSPEC : key->type;
struct sshkey *found = NULL;
struct sshauthopt *keyopts = NULL, *certopts = NULL, *finalopts = NULL;
char *key_options = NULL, *fp = NULL;
const char *reason = NULL;
int ret = -1;
if (authoptsp != NULL)
*authoptsp = NULL;
if ((found = sshkey_new(want_keytype)) == NULL) {
debug3_f("keytype %d failed", want_keytype);
goto out;
}
/* XXX djm: peek at key type in line and skip if unwanted */
if (sshkey_read(found, &cp) != 0) {
/* no key? check for options */
debug2("%s: check options: '%s'", loc, cp);
key_options = cp;
if (sshkey_advance_past_options(&cp) != 0) {
reason = "invalid key option string";
goto fail_reason;
}
skip_space(&cp);
if (sshkey_read(found, &cp) != 0) {
/* still no key? advance to next line*/
debug2("%s: advance: '%s'", loc, cp);
goto out;
}
}
/* Parse key options now; we need to know if this is a CA key */
if ((keyopts = sshauthopt_parse(key_options, &reason)) == NULL) {
debug("%s: bad key options: %s", loc, reason);
auth_debug_add("%s: bad key options: %s", loc, reason);
goto out;
}
/* Ignore keys that don't match or incorrectly marked as CAs */
if (sshkey_is_cert(key)) {
/* Certificate; check signature key against CA */
if (!sshkey_equal(found, key->cert->signature_key) ||
!keyopts->cert_authority)
goto out;
} else {
/* Plain key: check it against key found in file */
if (!sshkey_equal(found, key) || keyopts->cert_authority)
goto out;
}
/* We have a candidate key, perform authorisation checks */
if ((fp = sshkey_fingerprint(found,
options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
fatal_f("fingerprint failed");
debug("%s: matching %s found: %s %s", loc,
sshkey_is_cert(key) ? "CA" : "key", sshkey_type(found), fp);
if (auth_authorise_keyopts(pw, keyopts,
sshkey_is_cert(key), remote_ip, remote_host, loc) != 0) {
reason = "Refused by key options";
goto fail_reason;
}
/* That's all we need for plain keys. */
if (!sshkey_is_cert(key)) {
verbose("Accepted key %s %s found at %s",
sshkey_type(found), fp, loc);
finalopts = keyopts;
keyopts = NULL;
goto success;
}
/*
* Additional authorisation for certificates.
*/
/* Parse and check options present in certificate */
if ((certopts = sshauthopt_from_cert(key)) == NULL) {
reason = "Invalid certificate options";
goto fail_reason;
}
if (auth_authorise_keyopts(pw, certopts, 0,
remote_ip, remote_host, loc) != 0) {
reason = "Refused by certificate options";
goto fail_reason;
}
if ((finalopts = sshauthopt_merge(keyopts, certopts, &reason)) == NULL)
goto fail_reason;
/*
* If the user has specified a list of principals as
* a key option, then prefer that list to matching
* their username in the certificate principals list.
*/
if (keyopts->cert_principals != NULL &&
!match_principals_option(keyopts->cert_principals, key->cert)) {
reason = "Certificate does not contain an authorized principal";
goto fail_reason;
}
if (sshkey_cert_check_authority_now(key, 0, 0, 0,
keyopts->cert_principals == NULL ? pw->pw_name : NULL,
&reason) != 0)
goto fail_reason;
verbose("Accepted certificate ID \"%s\" (serial %llu) "
"signed by CA %s %s found at %s",
key->cert->key_id,
(unsigned long long)key->cert->serial,
sshkey_type(found), fp, loc);
success:
if (finalopts == NULL)
fatal_f("internal error: missing options");
if (authoptsp != NULL) {
*authoptsp = finalopts;
finalopts = NULL;
}
/* success */
ret = 0;
goto out;
fail_reason:
error("%s", reason);
auth_debug_add("%s", reason);
out:
free(fp);
sshauthopt_free(keyopts);
sshauthopt_free(certopts);
sshauthopt_free(finalopts);
sshkey_free(found);
return ret;
}
/*
* Checks whether key is allowed in authorized_keys-format file,
* returns 1 if the key is allowed or 0 otherwise.
*/
static int
check_authkeys_file(struct passwd *pw, FILE *f, char *file,
struct sshkey *key, const char *remote_ip,
const char *remote_host, struct sshauthopt **authoptsp)
{
char *cp, *line = NULL, loc[256];
size_t linesize = 0;
int found_key = 0;
u_long linenum = 0, nonblank = 0;
if (authoptsp != NULL)
*authoptsp = NULL;
while (getline(&line, &linesize, f) != -1) {
linenum++;
/* Always consume entire file */
if (found_key)
continue;
/* Skip leading whitespace, empty and comment lines. */
cp = line;
skip_space(&cp);
if (!*cp || *cp == '\n' || *cp == '#')
continue;
nonblank++;
snprintf(loc, sizeof(loc), "%.200s:%lu", file, linenum);
if (check_authkey_line(pw, key, cp,
remote_ip, remote_host, loc, authoptsp) == 0)
found_key = 1;
}
free(line);
debug2_f("%s: processed %lu/%lu lines", file, nonblank, linenum);
return found_key;
}
/* Authenticate a certificate key against TrustedUserCAKeys */ /* Authenticate a certificate key against TrustedUserCAKeys */
static int static int
user_cert_trusted_ca(struct passwd *pw, struct sshkey *key, user_cert_trusted_ca(struct passwd *pw, struct sshkey *key,
@ -902,7 +603,7 @@ user_key_allowed2(struct passwd *pw, struct sshkey *key,
debug("trying public key file %s", file); debug("trying public key file %s", file);
if ((f = auth_openkeyfile(file, pw, options.strict_modes)) != NULL) { if ((f = auth_openkeyfile(file, pw, options.strict_modes)) != NULL) {
found_key = check_authkeys_file(pw, f, file, found_key = auth_check_authkeys_file(pw, f, file,
key, remote_ip, remote_host, authoptsp); key, remote_ip, remote_host, authoptsp);
fclose(f); fclose(f);
} }
@ -1018,7 +719,7 @@ user_key_command_allowed2(struct passwd *user_pw, struct sshkey *key,
uid_swapped = 1; uid_swapped = 1;
temporarily_use_uid(runas_pw); temporarily_use_uid(runas_pw);
ok = check_authkeys_file(user_pw, f, ok = auth_check_authkeys_file(user_pw, f,
options.authorized_keys_command, key, remote_ip, options.authorized_keys_command, key, remote_ip,
remote_host, authoptsp); remote_host, authoptsp);

442
auth2-pubkeyfile.c Normal file
View File

@ -0,0 +1,442 @@
/* $OpenBSD: auth2-pubkeyfile.c,v 1.1 2022/05/27 05:02:46 djm Exp $ */
/*
* Copyright (c) 2000 Markus Friedl. All rights reserved.
* Copyright (c) 2010 Damien Miller. 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.
*
* 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.
*/
#include "includes.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include "ssh.h"
#include "log.h"
#include "misc.h"
#include "compat.h"
#include "sshkey.h"
#include "digest.h"
#include "hostfile.h"
#include "auth.h"
#include "auth-options.h"
#include "authfile.h"
#include "match.h"
#include "ssherr.h"
int
auth_authorise_keyopts(struct passwd *pw, struct sshauthopt *opts,
int allow_cert_authority, const char *remote_ip, const char *remote_host,
const char *loc)
{
time_t now = time(NULL);
char buf[64];
/*
* Check keys/principals file expiry time.
* NB. validity interval in certificate is handled elsewhere.
*/
if (opts->valid_before && now > 0 &&
opts->valid_before < (uint64_t)now) {
format_absolute_time(opts->valid_before, buf, sizeof(buf));
debug("%s: entry expired at %s", loc, buf);
auth_debug_add("%s: entry expired at %s", loc, buf);
return -1;
}
/* Consistency checks */
if (opts->cert_principals != NULL && !opts->cert_authority) {
debug("%s: principals on non-CA key", loc);
auth_debug_add("%s: principals on non-CA key", loc);
/* deny access */
return -1;
}
/* cert-authority flag isn't valid in authorized_principals files */
if (!allow_cert_authority && opts->cert_authority) {
debug("%s: cert-authority flag invalid here", loc);
auth_debug_add("%s: cert-authority flag invalid here", loc);
/* deny access */
return -1;
}
/* Perform from= checks */
if (opts->required_from_host_keys != NULL) {
switch (match_host_and_ip(remote_host, remote_ip,
opts->required_from_host_keys )) {
case 1:
/* Host name matches. */
break;
case -1:
default:
debug("%s: invalid from criteria", loc);
auth_debug_add("%s: invalid from criteria", loc);
/* FALLTHROUGH */
case 0:
logit("%s: Authentication tried for %.100s with "
"correct key but not from a permitted "
"host (host=%.200s, ip=%.200s, required=%.200s).",
loc, pw->pw_name, remote_host, remote_ip,
opts->required_from_host_keys);
auth_debug_add("%s: Your host '%.200s' is not "
"permitted to use this key for login.",
loc, remote_host);
/* deny access */
return -1;
}
}
/* Check source-address restriction from certificate */
if (opts->required_from_host_cert != NULL) {
switch (addr_match_cidr_list(remote_ip,
opts->required_from_host_cert)) {
case 1:
/* accepted */
break;
case -1:
default:
/* invalid */
error("%s: Certificate source-address invalid", loc);
/* FALLTHROUGH */
case 0:
logit("%s: Authentication tried for %.100s with valid "
"certificate but not from a permitted source "
"address (%.200s).", loc, pw->pw_name, remote_ip);
auth_debug_add("%s: Your address '%.200s' is not "
"permitted to use this certificate for login.",
loc, remote_ip);
return -1;
}
}
/*
*
* XXX this is spammy. We should report remotely only for keys
* that are successful in actual auth attempts, and not PK_OK
* tests.
*/
auth_log_authopts(loc, opts, 1);
return 0;
}
static int
match_principals_option(const char *principal_list, struct sshkey_cert *cert)
{
char *result;
u_int i;
/* XXX percent_expand() sequences for authorized_principals? */
for (i = 0; i < cert->nprincipals; i++) {
if ((result = match_list(cert->principals[i],
principal_list, NULL)) != NULL) {
debug3("matched principal from key options \"%.100s\"",
result);
free(result);
return 1;
}
}
return 0;
}
/*
* Process a single authorized_principals format line. Returns 0 and sets
* authoptsp is principal is authorised, -1 otherwise. "loc" is used as a
* log preamble for file/line information.
*/
int
auth_check_principals_line(char *cp, const struct sshkey_cert *cert,
const char *loc, struct sshauthopt **authoptsp)
{
u_int i, found = 0;
char *ep, *line_opts;
const char *reason = NULL;
struct sshauthopt *opts = NULL;
if (authoptsp != NULL)
*authoptsp = NULL;
/* Trim trailing whitespace. */
ep = cp + strlen(cp) - 1;
while (ep > cp && (*ep == '\n' || *ep == ' ' || *ep == '\t'))
*ep-- = '\0';
/*
* If the line has internal whitespace then assume it has
* key options.
*/
line_opts = NULL;
if ((ep = strrchr(cp, ' ')) != NULL ||
(ep = strrchr(cp, '\t')) != NULL) {
for (; *ep == ' ' || *ep == '\t'; ep++)
;
line_opts = cp;
cp = ep;
}
if ((opts = sshauthopt_parse(line_opts, &reason)) == NULL) {
debug("%s: bad principals options: %s", loc, reason);
auth_debug_add("%s: bad principals options: %s", loc, reason);
return -1;
}
/* Check principals in cert against those on line */
for (i = 0; i < cert->nprincipals; i++) {
if (strcmp(cp, cert->principals[i]) != 0)
continue;
debug3("%s: matched principal \"%.100s\"",
loc, cert->principals[i]);
found = 1;
}
if (found && authoptsp != NULL) {
*authoptsp = opts;
opts = NULL;
}
sshauthopt_free(opts);
return found ? 0 : -1;
}
int
auth_process_principals(FILE *f, const char *file,
const struct sshkey_cert *cert, struct sshauthopt **authoptsp)
{
char loc[256], *line = NULL, *cp, *ep;
size_t linesize = 0;
u_long linenum = 0, nonblank = 0;
u_int found_principal = 0;
if (authoptsp != NULL)
*authoptsp = NULL;
while (getline(&line, &linesize, f) != -1) {
linenum++;
/* Always consume entire input */
if (found_principal)
continue;
/* Skip leading whitespace. */
for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
;
/* Skip blank and comment lines. */
if ((ep = strchr(cp, '#')) != NULL)
*ep = '\0';
if (!*cp || *cp == '\n')
continue;
nonblank++;
snprintf(loc, sizeof(loc), "%.200s:%lu", file, linenum);
if (auth_check_principals_line(cp, cert, loc, authoptsp) == 0)
found_principal = 1;
}
debug2_f("%s: processed %lu/%lu lines", file, nonblank, linenum);
free(line);
return found_principal;
}
/*
* Check a single line of an authorized_keys-format file. Returns 0 if key
* matches, -1 otherwise. Will return key/cert options via *authoptsp
* on success. "loc" is used as file/line location in log messages.
*/
int
auth_check_authkey_line(struct passwd *pw, struct sshkey *key,
char *cp, const char *remote_ip, const char *remote_host, const char *loc,
struct sshauthopt **authoptsp)
{
int want_keytype = sshkey_is_cert(key) ? KEY_UNSPEC : key->type;
struct sshkey *found = NULL;
struct sshauthopt *keyopts = NULL, *certopts = NULL, *finalopts = NULL;
char *key_options = NULL, *fp = NULL;
const char *reason = NULL;
int ret = -1;
if (authoptsp != NULL)
*authoptsp = NULL;
if ((found = sshkey_new(want_keytype)) == NULL) {
debug3_f("keytype %d failed", want_keytype);
goto out;
}
/* XXX djm: peek at key type in line and skip if unwanted */
if (sshkey_read(found, &cp) != 0) {
/* no key? check for options */
debug2("%s: check options: '%s'", loc, cp);
key_options = cp;
if (sshkey_advance_past_options(&cp) != 0) {
reason = "invalid key option string";
goto fail_reason;
}
skip_space(&cp);
if (sshkey_read(found, &cp) != 0) {
/* still no key? advance to next line*/
debug2("%s: advance: '%s'", loc, cp);
goto out;
}
}
/* Parse key options now; we need to know if this is a CA key */
if ((keyopts = sshauthopt_parse(key_options, &reason)) == NULL) {
debug("%s: bad key options: %s", loc, reason);
auth_debug_add("%s: bad key options: %s", loc, reason);
goto out;
}
/* Ignore keys that don't match or incorrectly marked as CAs */
if (sshkey_is_cert(key)) {
/* Certificate; check signature key against CA */
if (!sshkey_equal(found, key->cert->signature_key) ||
!keyopts->cert_authority)
goto out;
} else {
/* Plain key: check it against key found in file */
if (!sshkey_equal(found, key) || keyopts->cert_authority)
goto out;
}
/* We have a candidate key, perform authorisation checks */
if ((fp = sshkey_fingerprint(found,
SSH_FP_HASH_DEFAULT, SSH_FP_DEFAULT)) == NULL)
fatal_f("fingerprint failed");
debug("%s: matching %s found: %s %s", loc,
sshkey_is_cert(key) ? "CA" : "key", sshkey_type(found), fp);
if (auth_authorise_keyopts(pw, keyopts,
sshkey_is_cert(key), remote_ip, remote_host, loc) != 0) {
reason = "Refused by key options";
goto fail_reason;
}
/* That's all we need for plain keys. */
if (!sshkey_is_cert(key)) {
verbose("Accepted key %s %s found at %s",
sshkey_type(found), fp, loc);
finalopts = keyopts;
keyopts = NULL;
goto success;
}
/*
* Additional authorisation for certificates.
*/
/* Parse and check options present in certificate */
if ((certopts = sshauthopt_from_cert(key)) == NULL) {
reason = "Invalid certificate options";
goto fail_reason;
}
if (auth_authorise_keyopts(pw, certopts, 0,
remote_ip, remote_host, loc) != 0) {
reason = "Refused by certificate options";
goto fail_reason;
}
if ((finalopts = sshauthopt_merge(keyopts, certopts, &reason)) == NULL)
goto fail_reason;
/*
* If the user has specified a list of principals as
* a key option, then prefer that list to matching
* their username in the certificate principals list.
*/
if (keyopts->cert_principals != NULL &&
!match_principals_option(keyopts->cert_principals, key->cert)) {
reason = "Certificate does not contain an authorized principal";
goto fail_reason;
}
if (sshkey_cert_check_authority_now(key, 0, 0, 0,
keyopts->cert_principals == NULL ? pw->pw_name : NULL,
&reason) != 0)
goto fail_reason;
verbose("Accepted certificate ID \"%s\" (serial %llu) "
"signed by CA %s %s found at %s",
key->cert->key_id,
(unsigned long long)key->cert->serial,
sshkey_type(found), fp, loc);
success:
if (finalopts == NULL)
fatal_f("internal error: missing options");
if (authoptsp != NULL) {
*authoptsp = finalopts;
finalopts = NULL;
}
/* success */
ret = 0;
goto out;
fail_reason:
error("%s", reason);
auth_debug_add("%s", reason);
out:
free(fp);
sshauthopt_free(keyopts);
sshauthopt_free(certopts);
sshauthopt_free(finalopts);
sshkey_free(found);
return ret;
}
/*
* Checks whether key is allowed in authorized_keys-format file,
* returns 1 if the key is allowed or 0 otherwise.
*/
int
auth_check_authkeys_file(struct passwd *pw, FILE *f, char *file,
struct sshkey *key, const char *remote_ip,
const char *remote_host, struct sshauthopt **authoptsp)
{
char *cp, *line = NULL, loc[256];
size_t linesize = 0;
int found_key = 0;
u_long linenum = 0, nonblank = 0;
if (authoptsp != NULL)
*authoptsp = NULL;
while (getline(&line, &linesize, f) != -1) {
linenum++;
/* Always consume entire file */
if (found_key)
continue;
/* Skip leading whitespace, empty and comment lines. */
cp = line;
skip_space(&cp);
if (!*cp || *cp == '\n' || *cp == '#')
continue;
nonblank++;
snprintf(loc, sizeof(loc), "%.200s:%lu", file, linenum);
if (auth_check_authkey_line(pw, key, cp,
remote_ip, remote_host, loc, authoptsp) == 0)
found_key = 1;
}
free(line);
debug2_f("%s: processed %lu/%lu lines", file, nonblank, linenum);
return found_key;
}