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openssh-portable/packet.c
djm@openbsd.org a4b5bc246c
upstream: typos 
OpenBSD-Commit-ID: edfa72eb06bfa65da30fabf7d2fe76d2d33f77bf
2024-05-31 19:04:11 +10:00

2858 lines
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/* $OpenBSD: packet.c,v 1.315 2024/05/31 08:49:35 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
* This file contains code implementing the packet protocol and communication
* with the other side. This same code is used both on client and server side.
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*
*
* SSH2 packet format added by Markus Friedl.
* Copyright (c) 2000, 2001 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.
*
* 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 "openbsd-compat/sys-queue.h"
#include <sys/socket.h>
#ifdef HAVE_SYS_TIME_H
# include <sys/time.h>
#endif
#include <netinet/in.h>
#include <netinet/ip.h>
#include <arpa/inet.h>
#include <errno.h>
#include <netdb.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#ifdef HAVE_POLL_H
#include <poll.h>
#endif
#include <signal.h>
#include <time.h>
/*
* Explicitly include OpenSSL before zlib as some versions of OpenSSL have
* "free_func" in their headers, which zlib typedefs.
*/
#ifdef WITH_OPENSSL
# include <openssl/bn.h>
# include <openssl/evp.h>
# ifdef OPENSSL_HAS_ECC
# include <openssl/ec.h>
# endif
#endif
#ifdef WITH_ZLIB
#include <zlib.h>
#endif
#include "xmalloc.h"
#include "compat.h"
#include "ssh2.h"
#include "cipher.h"
#include "sshkey.h"
#include "kex.h"
#include "digest.h"
#include "mac.h"
#include "log.h"
#include "canohost.h"
#include "misc.h"
#include "channels.h"
#include "ssh.h"
#include "packet.h"
#include "ssherr.h"
#include "sshbuf.h"
#ifdef PACKET_DEBUG
#define DBG(x) x
#else
#define DBG(x)
#endif
#define PACKET_MAX_SIZE (256 * 1024)
struct packet_state {
u_int32_t seqnr;
u_int32_t packets;
u_int64_t blocks;
u_int64_t bytes;
};
struct packet {
TAILQ_ENTRY(packet) next;
u_char type;
struct sshbuf *payload;
};
struct session_state {
/*
* This variable contains the file descriptors used for
* communicating with the other side. connection_in is used for
* reading; connection_out for writing. These can be the same
* descriptor, in which case it is assumed to be a socket.
*/
int connection_in;
int connection_out;
/* Protocol flags for the remote side. */
u_int remote_protocol_flags;
/* Encryption context for receiving data. Only used for decryption. */
struct sshcipher_ctx *receive_context;
/* Encryption context for sending data. Only used for encryption. */
struct sshcipher_ctx *send_context;
/* Buffer for raw input data from the socket. */
struct sshbuf *input;
/* Buffer for raw output data going to the socket. */
struct sshbuf *output;
/* Buffer for the partial outgoing packet being constructed. */
struct sshbuf *outgoing_packet;
/* Buffer for the incoming packet currently being processed. */
struct sshbuf *incoming_packet;
/* Scratch buffer for packet compression/decompression. */
struct sshbuf *compression_buffer;
#ifdef WITH_ZLIB
/* Incoming/outgoing compression dictionaries */
z_stream compression_in_stream;
z_stream compression_out_stream;
#endif
int compression_in_started;
int compression_out_started;
int compression_in_failures;
int compression_out_failures;
/* default maximum packet size */
u_int max_packet_size;
/* Flag indicating whether this module has been initialized. */
int initialized;
/* Set to true if the connection is interactive. */
int interactive_mode;
/* Set to true if we are the server side. */
int server_side;
/* Set to true if we are authenticated. */
int after_authentication;
int keep_alive_timeouts;
/* The maximum time that we will wait to send or receive a packet */
int packet_timeout_ms;
/* Session key information for Encryption and MAC */
struct newkeys *newkeys[MODE_MAX];
struct packet_state p_read, p_send;
/* Volume-based rekeying */
u_int64_t max_blocks_in, max_blocks_out, rekey_limit;
/* Time-based rekeying */
u_int32_t rekey_interval; /* how often in seconds */
time_t rekey_time; /* time of last rekeying */
/* roundup current message to extra_pad bytes */
u_char extra_pad;
/* XXX discard incoming data after MAC error */
u_int packet_discard;
size_t packet_discard_mac_already;
struct sshmac *packet_discard_mac;
/* Used in packet_read_poll2() */
u_int packlen;
/* Used in packet_send2 */
int rekeying;
/* Used in ssh_packet_send_mux() */
int mux;
/* Used in packet_set_interactive */
int set_interactive_called;
/* Used in packet_set_maxsize */
int set_maxsize_called;
/* One-off warning about weak ciphers */
int cipher_warning_done;
/* Hook for fuzzing inbound packets */
ssh_packet_hook_fn *hook_in;
void *hook_in_ctx;
TAILQ_HEAD(, packet) outgoing;
};
struct ssh *
ssh_alloc_session_state(void)
{
struct ssh *ssh = NULL;
struct session_state *state = NULL;
if ((ssh = calloc(1, sizeof(*ssh))) == NULL ||
(state = calloc(1, sizeof(*state))) == NULL ||
(ssh->kex = kex_new()) == NULL ||
(state->input = sshbuf_new()) == NULL ||
(state->output = sshbuf_new()) == NULL ||
(state->outgoing_packet = sshbuf_new()) == NULL ||
(state->incoming_packet = sshbuf_new()) == NULL)
goto fail;
TAILQ_INIT(&state->outgoing);
TAILQ_INIT(&ssh->private_keys);
TAILQ_INIT(&ssh->public_keys);
state->connection_in = -1;
state->connection_out = -1;
state->max_packet_size = 32768;
state->packet_timeout_ms = -1;
state->p_send.packets = state->p_read.packets = 0;
state->initialized = 1;
/*
* ssh_packet_send2() needs to queue packets until
* we've done the initial key exchange.
*/
state->rekeying = 1;
ssh->state = state;
return ssh;
fail:
if (ssh) {
kex_free(ssh->kex);
free(ssh);
}
if (state) {
sshbuf_free(state->input);
sshbuf_free(state->output);
sshbuf_free(state->incoming_packet);
sshbuf_free(state->outgoing_packet);
free(state);
}
return NULL;
}
void
ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx)
{
ssh->state->hook_in = hook;
ssh->state->hook_in_ctx = ctx;
}
/* Returns nonzero if rekeying is in progress */
int
ssh_packet_is_rekeying(struct ssh *ssh)
{
return ssh->state->rekeying ||
(ssh->kex != NULL && ssh->kex->done == 0);
}
/*
* Sets the descriptors used for communication.
*/
struct ssh *
ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out)
{
struct session_state *state;
const struct sshcipher *none = cipher_by_name("none");
int r;
if (none == NULL) {
error_f("cannot load cipher 'none'");
return NULL;
}
if (ssh == NULL)
ssh = ssh_alloc_session_state();
if (ssh == NULL) {
error_f("could not allocate state");
return NULL;
}
state = ssh->state;
state->connection_in = fd_in;
state->connection_out = fd_out;
if ((r = cipher_init(&state->send_context, none,
(const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 ||
(r = cipher_init(&state->receive_context, none,
(const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) {
error_fr(r, "cipher_init failed");
free(ssh); /* XXX need ssh_free_session_state? */
return NULL;
}
state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL;
/*
* Cache the IP address of the remote connection for use in error
* messages that might be generated after the connection has closed.
*/
(void)ssh_remote_ipaddr(ssh);
return ssh;
}
void
ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count)
{
struct session_state *state = ssh->state;
if (timeout <= 0 || count <= 0) {
state->packet_timeout_ms = -1;
return;
}
if ((INT_MAX / 1000) / count < timeout)
state->packet_timeout_ms = INT_MAX;
else
state->packet_timeout_ms = timeout * count * 1000;
}
void
ssh_packet_set_mux(struct ssh *ssh)
{
ssh->state->mux = 1;
ssh->state->rekeying = 0;
kex_free(ssh->kex);
ssh->kex = NULL;
}
int
ssh_packet_get_mux(struct ssh *ssh)
{
return ssh->state->mux;
}
int
ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...)
{
va_list args;
int r;
free(ssh->log_preamble);
if (fmt == NULL)
ssh->log_preamble = NULL;
else {
va_start(args, fmt);
r = vasprintf(&ssh->log_preamble, fmt, args);
va_end(args);
if (r < 0 || ssh->log_preamble == NULL)
return SSH_ERR_ALLOC_FAIL;
}
return 0;
}
int
ssh_packet_stop_discard(struct ssh *ssh)
{
struct session_state *state = ssh->state;
int r;
if (state->packet_discard_mac) {
char buf[1024];
size_t dlen = PACKET_MAX_SIZE;
if (dlen > state->packet_discard_mac_already)
dlen -= state->packet_discard_mac_already;
memset(buf, 'a', sizeof(buf));
while (sshbuf_len(state->incoming_packet) < dlen)
if ((r = sshbuf_put(state->incoming_packet, buf,
sizeof(buf))) != 0)
return r;
(void) mac_compute(state->packet_discard_mac,
state->p_read.seqnr,
sshbuf_ptr(state->incoming_packet), dlen,
NULL, 0);
}
logit("Finished discarding for %.200s port %d",
ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
return SSH_ERR_MAC_INVALID;
}
static int
ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc,
struct sshmac *mac, size_t mac_already, u_int discard)
{
struct session_state *state = ssh->state;
int r;
if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) {
if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
return r;
return SSH_ERR_MAC_INVALID;
}
/*
* Record number of bytes over which the mac has already
* been computed in order to minimize timing attacks.
*/
if (mac && mac->enabled) {
state->packet_discard_mac = mac;
state->packet_discard_mac_already = mac_already;
}
if (sshbuf_len(state->input) >= discard)
return ssh_packet_stop_discard(ssh);
state->packet_discard = discard - sshbuf_len(state->input);
return 0;
}
/* Returns 1 if remote host is connected via socket, 0 if not. */
int
ssh_packet_connection_is_on_socket(struct ssh *ssh)
{
struct session_state *state;
struct sockaddr_storage from, to;
socklen_t fromlen, tolen;
if (ssh == NULL || ssh->state == NULL)
return 0;
state = ssh->state;
if (state->connection_in == -1 || state->connection_out == -1)
return 0;
/* filedescriptors in and out are the same, so it's a socket */
if (state->connection_in == state->connection_out)
return 1;
fromlen = sizeof(from);
memset(&from, 0, sizeof(from));
if (getpeername(state->connection_in, (struct sockaddr *)&from,
&fromlen) == -1)
return 0;
tolen = sizeof(to);
memset(&to, 0, sizeof(to));
if (getpeername(state->connection_out, (struct sockaddr *)&to,
&tolen) == -1)
return 0;
if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
return 0;
if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
return 0;
return 1;
}
void
ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes)
{
if (ibytes)
*ibytes = ssh->state->p_read.bytes;
if (obytes)
*obytes = ssh->state->p_send.bytes;
}
int
ssh_packet_connection_af(struct ssh *ssh)
{
return get_sock_af(ssh->state->connection_out);
}
/* Sets the connection into non-blocking mode. */
void
ssh_packet_set_nonblocking(struct ssh *ssh)
{
/* Set the socket into non-blocking mode. */
set_nonblock(ssh->state->connection_in);
if (ssh->state->connection_out != ssh->state->connection_in)
set_nonblock(ssh->state->connection_out);
}
/* Returns the socket used for reading. */
int
ssh_packet_get_connection_in(struct ssh *ssh)
{
return ssh->state->connection_in;
}
/* Returns the descriptor used for writing. */
int
ssh_packet_get_connection_out(struct ssh *ssh)
{
return ssh->state->connection_out;
}
/*
* Returns the IP-address of the remote host as a string. The returned
* string must not be freed.
*/
const char *
ssh_remote_ipaddr(struct ssh *ssh)
{
int sock;
/* Check whether we have cached the ipaddr. */
if (ssh->remote_ipaddr == NULL) {
if (ssh_packet_connection_is_on_socket(ssh)) {
sock = ssh->state->connection_in;
ssh->remote_ipaddr = get_peer_ipaddr(sock);
ssh->remote_port = get_peer_port(sock);
ssh->local_ipaddr = get_local_ipaddr(sock);
ssh->local_port = get_local_port(sock);
} else {
ssh->remote_ipaddr = xstrdup("UNKNOWN");
ssh->remote_port = 65535;
ssh->local_ipaddr = xstrdup("UNKNOWN");
ssh->local_port = 65535;
}
}
return ssh->remote_ipaddr;
}
/*
* Returns the remote DNS hostname as a string. The returned string must not
* be freed. NB. this will usually trigger a DNS query. Return value is on
* heap and no caching is performed.
* This function does additional checks on the hostname to mitigate some
* attacks based on conflation of hostnames and addresses and will
* fall back to returning an address on error.
*/
char *
ssh_remote_hostname(struct ssh *ssh)
{
struct sockaddr_storage from;
socklen_t fromlen;
struct addrinfo hints, *ai, *aitop;
char name[NI_MAXHOST], ntop2[NI_MAXHOST];
const char *ntop = ssh_remote_ipaddr(ssh);
/* Get IP address of client. */
fromlen = sizeof(from);
memset(&from, 0, sizeof(from));
if (getpeername(ssh_packet_get_connection_in(ssh),
(struct sockaddr *)&from, &fromlen) == -1) {
debug_f("getpeername failed: %.100s", strerror(errno));
return xstrdup(ntop);
}
ipv64_normalise_mapped(&from, &fromlen);
if (from.ss_family == AF_INET6)
fromlen = sizeof(struct sockaddr_in6);
debug3("trying to reverse map address %.100s.", ntop);
/* Map the IP address to a host name. */
if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
NULL, 0, NI_NAMEREQD) != 0) {
/* Host name not found. Use ip address. */
return xstrdup(ntop);
}
/*
* if reverse lookup result looks like a numeric hostname,
* someone is trying to trick us by PTR record like following:
* 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
*/
memset(&hints, 0, sizeof(hints));
hints.ai_socktype = SOCK_DGRAM; /*dummy*/
hints.ai_flags = AI_NUMERICHOST;
if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
name, ntop);
freeaddrinfo(ai);
return xstrdup(ntop);
}
/* Names are stored in lowercase. */
lowercase(name);
/*
* Map it back to an IP address and check that the given
* address actually is an address of this host. This is
* necessary because anyone with access to a name server can
* define arbitrary names for an IP address. Mapping from
* name to IP address can be trusted better (but can still be
* fooled if the intruder has access to the name server of
* the domain).
*/
memset(&hints, 0, sizeof(hints));
hints.ai_family = from.ss_family;
hints.ai_socktype = SOCK_STREAM;
if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
logit("reverse mapping checking getaddrinfo for %.700s "
"[%s] failed.", name, ntop);
return xstrdup(ntop);
}
/* Look for the address from the list of addresses. */
for (ai = aitop; ai; ai = ai->ai_next) {
if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
(strcmp(ntop, ntop2) == 0))
break;
}
freeaddrinfo(aitop);
/* If we reached the end of the list, the address was not there. */
if (ai == NULL) {
/* Address not found for the host name. */
logit("Address %.100s maps to %.600s, but this does not "
"map back to the address.", ntop, name);
return xstrdup(ntop);
}
return xstrdup(name);
}
/* Returns the port number of the remote host. */
int
ssh_remote_port(struct ssh *ssh)
{
(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
return ssh->remote_port;
}
/*
* Returns the IP-address of the local host as a string. The returned
* string must not be freed.
*/
const char *
ssh_local_ipaddr(struct ssh *ssh)
{
(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
return ssh->local_ipaddr;
}
/* Returns the port number of the local host. */
int
ssh_local_port(struct ssh *ssh)
{
(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
return ssh->local_port;
}
/* Returns the routing domain of the input socket, or NULL if unavailable */
const char *
ssh_packet_rdomain_in(struct ssh *ssh)
{
if (ssh->rdomain_in != NULL)
return ssh->rdomain_in;
if (!ssh_packet_connection_is_on_socket(ssh))
return NULL;
ssh->rdomain_in = get_rdomain(ssh->state->connection_in);
return ssh->rdomain_in;
}
/* Closes the connection and clears and frees internal data structures. */
static void
ssh_packet_close_internal(struct ssh *ssh, int do_close)
{
struct session_state *state = ssh->state;
u_int mode;
if (!state->initialized)
return;
state->initialized = 0;
if (do_close) {
if (state->connection_in == state->connection_out) {
close(state->connection_out);
} else {
close(state->connection_in);
close(state->connection_out);
}
}
sshbuf_free(state->input);
sshbuf_free(state->output);
sshbuf_free(state->outgoing_packet);
sshbuf_free(state->incoming_packet);
for (mode = 0; mode < MODE_MAX; mode++) {
kex_free_newkeys(state->newkeys[mode]); /* current keys */
state->newkeys[mode] = NULL;
ssh_clear_newkeys(ssh, mode); /* next keys */
}
#ifdef WITH_ZLIB
/* compression state is in shared mem, so we can only release it once */
if (do_close && state->compression_buffer) {
sshbuf_free(state->compression_buffer);
if (state->compression_out_started) {
z_streamp stream = &state->compression_out_stream;
debug("compress outgoing: "
"raw data %llu, compressed %llu, factor %.2f",
(unsigned long long)stream->total_in,
(unsigned long long)stream->total_out,
stream->total_in == 0 ? 0.0 :
(double) stream->total_out / stream->total_in);
if (state->compression_out_failures == 0)
deflateEnd(stream);
}
if (state->compression_in_started) {
z_streamp stream = &state->compression_in_stream;
debug("compress incoming: "
"raw data %llu, compressed %llu, factor %.2f",
(unsigned long long)stream->total_out,
(unsigned long long)stream->total_in,
stream->total_out == 0 ? 0.0 :
(double) stream->total_in / stream->total_out);
if (state->compression_in_failures == 0)
inflateEnd(stream);
}
}
#endif /* WITH_ZLIB */
cipher_free(state->send_context);
cipher_free(state->receive_context);
state->send_context = state->receive_context = NULL;
if (do_close) {
free(ssh->local_ipaddr);
ssh->local_ipaddr = NULL;
free(ssh->remote_ipaddr);
ssh->remote_ipaddr = NULL;
free(ssh->state);
ssh->state = NULL;
kex_free(ssh->kex);
ssh->kex = NULL;
}
}
void
ssh_packet_close(struct ssh *ssh)
{
ssh_packet_close_internal(ssh, 1);
}
void
ssh_packet_clear_keys(struct ssh *ssh)
{
ssh_packet_close_internal(ssh, 0);
}
/* Sets remote side protocol flags. */
void
ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags)
{
ssh->state->remote_protocol_flags = protocol_flags;
}
/* Returns the remote protocol flags set earlier by the above function. */
u_int
ssh_packet_get_protocol_flags(struct ssh *ssh)
{
return ssh->state->remote_protocol_flags;
}
/*
* Starts packet compression from the next packet on in both directions.
* Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
*/
static int
ssh_packet_init_compression(struct ssh *ssh)
{
if (!ssh->state->compression_buffer &&
((ssh->state->compression_buffer = sshbuf_new()) == NULL))
return SSH_ERR_ALLOC_FAIL;
return 0;
}
#ifdef WITH_ZLIB
static int
start_compression_out(struct ssh *ssh, int level)
{
if (level < 1 || level > 9)
return SSH_ERR_INVALID_ARGUMENT;
debug("Enabling compression at level %d.", level);
if (ssh->state->compression_out_started == 1)
deflateEnd(&ssh->state->compression_out_stream);
switch (deflateInit(&ssh->state->compression_out_stream, level)) {
case Z_OK:
ssh->state->compression_out_started = 1;
break;
case Z_MEM_ERROR:
return SSH_ERR_ALLOC_FAIL;
default:
return SSH_ERR_INTERNAL_ERROR;
}
return 0;
}
static int
start_compression_in(struct ssh *ssh)
{
if (ssh->state->compression_in_started == 1)
inflateEnd(&ssh->state->compression_in_stream);
switch (inflateInit(&ssh->state->compression_in_stream)) {
case Z_OK:
ssh->state->compression_in_started = 1;
break;
case Z_MEM_ERROR:
return SSH_ERR_ALLOC_FAIL;
default:
return SSH_ERR_INTERNAL_ERROR;
}
return 0;
}
/* XXX remove need for separate compression buffer */
static int
compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
{
u_char buf[4096];
int r, status;
if (ssh->state->compression_out_started != 1)
return SSH_ERR_INTERNAL_ERROR;
/* This case is not handled below. */
if (sshbuf_len(in) == 0)
return 0;
/* Input is the contents of the input buffer. */
if ((ssh->state->compression_out_stream.next_in =
sshbuf_mutable_ptr(in)) == NULL)
return SSH_ERR_INTERNAL_ERROR;
ssh->state->compression_out_stream.avail_in = sshbuf_len(in);
/* Loop compressing until deflate() returns with avail_out != 0. */
do {
/* Set up fixed-size output buffer. */
ssh->state->compression_out_stream.next_out = buf;
ssh->state->compression_out_stream.avail_out = sizeof(buf);
/* Compress as much data into the buffer as possible. */
status = deflate(&ssh->state->compression_out_stream,
Z_PARTIAL_FLUSH);
switch (status) {
case Z_MEM_ERROR:
return SSH_ERR_ALLOC_FAIL;
case Z_OK:
/* Append compressed data to output_buffer. */
if ((r = sshbuf_put(out, buf, sizeof(buf) -
ssh->state->compression_out_stream.avail_out)) != 0)
return r;
break;
case Z_STREAM_ERROR:
default:
ssh->state->compression_out_failures++;
return SSH_ERR_INVALID_FORMAT;
}
} while (ssh->state->compression_out_stream.avail_out == 0);
return 0;
}
static int
uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
{
u_char buf[4096];
int r, status;
if (ssh->state->compression_in_started != 1)
return SSH_ERR_INTERNAL_ERROR;
if ((ssh->state->compression_in_stream.next_in =
sshbuf_mutable_ptr(in)) == NULL)
return SSH_ERR_INTERNAL_ERROR;
ssh->state->compression_in_stream.avail_in = sshbuf_len(in);
for (;;) {
/* Set up fixed-size output buffer. */
ssh->state->compression_in_stream.next_out = buf;
ssh->state->compression_in_stream.avail_out = sizeof(buf);
status = inflate(&ssh->state->compression_in_stream,
Z_SYNC_FLUSH);
switch (status) {
case Z_OK:
if ((r = sshbuf_put(out, buf, sizeof(buf) -
ssh->state->compression_in_stream.avail_out)) != 0)
return r;
break;
case Z_BUF_ERROR:
/*
* Comments in zlib.h say that we should keep calling
* inflate() until we get an error. This appears to
* be the error that we get.
*/
return 0;
case Z_DATA_ERROR:
return SSH_ERR_INVALID_FORMAT;
case Z_MEM_ERROR:
return SSH_ERR_ALLOC_FAIL;
case Z_STREAM_ERROR:
default:
ssh->state->compression_in_failures++;
return SSH_ERR_INTERNAL_ERROR;
}
}
/* NOTREACHED */
}
#else /* WITH_ZLIB */
static int
start_compression_out(struct ssh *ssh, int level)
{
return SSH_ERR_INTERNAL_ERROR;
}
static int
start_compression_in(struct ssh *ssh)
{
return SSH_ERR_INTERNAL_ERROR;
}
static int
compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
{
return SSH_ERR_INTERNAL_ERROR;
}
static int
uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
{
return SSH_ERR_INTERNAL_ERROR;
}
#endif /* WITH_ZLIB */
void
ssh_clear_newkeys(struct ssh *ssh, int mode)
{
if (ssh->kex && ssh->kex->newkeys[mode]) {
kex_free_newkeys(ssh->kex->newkeys[mode]);
ssh->kex->newkeys[mode] = NULL;
}
}
int
ssh_set_newkeys(struct ssh *ssh, int mode)
{
struct session_state *state = ssh->state;
struct sshenc *enc;
struct sshmac *mac;
struct sshcomp *comp;
struct sshcipher_ctx **ccp;
struct packet_state *ps;
u_int64_t *max_blocks;
const char *wmsg;
int r, crypt_type;
const char *dir = mode == MODE_OUT ? "out" : "in";
debug2_f("mode %d", mode);
if (mode == MODE_OUT) {
ccp = &state->send_context;
crypt_type = CIPHER_ENCRYPT;
ps = &state->p_send;
max_blocks = &state->max_blocks_out;
} else {
ccp = &state->receive_context;
crypt_type = CIPHER_DECRYPT;
ps = &state->p_read;
max_blocks = &state->max_blocks_in;
}
if (state->newkeys[mode] != NULL) {
debug_f("rekeying %s, input %llu bytes %llu blocks, "
"output %llu bytes %llu blocks", dir,
(unsigned long long)state->p_read.bytes,
(unsigned long long)state->p_read.blocks,
(unsigned long long)state->p_send.bytes,
(unsigned long long)state->p_send.blocks);
kex_free_newkeys(state->newkeys[mode]);
state->newkeys[mode] = NULL;
}
/* note that both bytes and the seqnr are not reset */
ps->packets = ps->blocks = 0;
/* move newkeys from kex to state */
if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL)
return SSH_ERR_INTERNAL_ERROR;
ssh->kex->newkeys[mode] = NULL;
enc = &state->newkeys[mode]->enc;
mac = &state->newkeys[mode]->mac;
comp = &state->newkeys[mode]->comp;
if (cipher_authlen(enc->cipher) == 0) {
if ((r = mac_init(mac)) != 0)
return r;
}
mac->enabled = 1;
DBG(debug_f("cipher_init: %s", dir));
cipher_free(*ccp);
*ccp = NULL;
if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len,
enc->iv, enc->iv_len, crypt_type)) != 0)
return r;
if (!state->cipher_warning_done &&
(wmsg = cipher_warning_message(*ccp)) != NULL) {
error("Warning: %s", wmsg);
state->cipher_warning_done = 1;
}
/* Deleting the keys does not gain extra security */
/* explicit_bzero(enc->iv, enc->block_size);
explicit_bzero(enc->key, enc->key_len);
explicit_bzero(mac->key, mac->key_len); */
if ((comp->type == COMP_ZLIB ||
(comp->type == COMP_DELAYED &&
state->after_authentication)) && comp->enabled == 0) {
if ((r = ssh_packet_init_compression(ssh)) < 0)
return r;
if (mode == MODE_OUT) {
if ((r = start_compression_out(ssh, 6)) != 0)
return r;
} else {
if ((r = start_compression_in(ssh)) != 0)
return r;
}
comp->enabled = 1;
}
/*
* The 2^(blocksize*2) limit is too expensive for 3DES,
* so enforce a 1GB limit for small blocksizes.
* See RFC4344 section 3.2.
*/
if (enc->block_size >= 16)
*max_blocks = (u_int64_t)1 << (enc->block_size*2);
else
*max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
if (state->rekey_limit)
*max_blocks = MINIMUM(*max_blocks,
state->rekey_limit / enc->block_size);
debug("rekey %s after %llu blocks", dir,
(unsigned long long)*max_blocks);
return 0;
}
#define MAX_PACKETS (1U<<31)
static int
ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len)
{
struct session_state *state = ssh->state;
u_int32_t out_blocks;
/* XXX client can't cope with rekeying pre-auth */
if (!state->after_authentication)
return 0;
/* Haven't keyed yet or KEX in progress. */
if (ssh_packet_is_rekeying(ssh))
return 0;
/* Peer can't rekey */
if (ssh->compat & SSH_BUG_NOREKEY)
return 0;
/*
* Permit one packet in or out per rekey - this allows us to
* make progress when rekey limits are very small.
*/
if (state->p_send.packets == 0 && state->p_read.packets == 0)
return 0;
/* Time-based rekeying */
if (state->rekey_interval != 0 &&
(int64_t)state->rekey_time + state->rekey_interval <= monotime())
return 1;
/*
* Always rekey when MAX_PACKETS sent in either direction
* As per RFC4344 section 3.1 we do this after 2^31 packets.
*/
if (state->p_send.packets > MAX_PACKETS ||
state->p_read.packets > MAX_PACKETS)
return 1;
/* Rekey after (cipher-specific) maximum blocks */
out_blocks = ROUNDUP(outbound_packet_len,
state->newkeys[MODE_OUT]->enc.block_size);
return (state->max_blocks_out &&
(state->p_send.blocks + out_blocks > state->max_blocks_out)) ||
(state->max_blocks_in &&
(state->p_read.blocks > state->max_blocks_in));
}
int
ssh_packet_check_rekey(struct ssh *ssh)
{
if (!ssh_packet_need_rekeying(ssh, 0))
return 0;
debug3_f("rekex triggered");
return kex_start_rekex(ssh);
}
/*
* Delayed compression for SSH2 is enabled after authentication:
* This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
* and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
*/
static int
ssh_packet_enable_delayed_compress(struct ssh *ssh)
{
struct session_state *state = ssh->state;
struct sshcomp *comp = NULL;
int r, mode;
/*
* Remember that we are past the authentication step, so rekeying
* with COMP_DELAYED will turn on compression immediately.
*/
state->after_authentication = 1;
for (mode = 0; mode < MODE_MAX; mode++) {
/* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
if (state->newkeys[mode] == NULL)
continue;
comp = &state->newkeys[mode]->comp;
if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
if ((r = ssh_packet_init_compression(ssh)) != 0)
return r;
if (mode == MODE_OUT) {
if ((r = start_compression_out(ssh, 6)) != 0)
return r;
} else {
if ((r = start_compression_in(ssh)) != 0)
return r;
}
comp->enabled = 1;
}
}
return 0;
}
/* Used to mute debug logging for noisy packet types */
int
ssh_packet_log_type(u_char type)
{
switch (type) {
case SSH2_MSG_PING:
case SSH2_MSG_PONG:
case SSH2_MSG_CHANNEL_DATA:
case SSH2_MSG_CHANNEL_EXTENDED_DATA:
case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
return 0;
default:
return 1;
}
}
/*
* Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
*/
int
ssh_packet_send2_wrapped(struct ssh *ssh)
{
struct session_state *state = ssh->state;
u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH];
u_char tmp, padlen, pad = 0;
u_int authlen = 0, aadlen = 0;
u_int len;
struct sshenc *enc = NULL;
struct sshmac *mac = NULL;
struct sshcomp *comp = NULL;
int r, block_size;
if (state->newkeys[MODE_OUT] != NULL) {
enc = &state->newkeys[MODE_OUT]->enc;
mac = &state->newkeys[MODE_OUT]->mac;
comp = &state->newkeys[MODE_OUT]->comp;
/* disable mac for authenticated encryption */
if ((authlen = cipher_authlen(enc->cipher)) != 0)
mac = NULL;
}
block_size = enc ? enc->block_size : 8;
aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
type = (sshbuf_ptr(state->outgoing_packet))[5];
if (ssh_packet_log_type(type))
debug3("send packet: type %u", type);
#ifdef PACKET_DEBUG
fprintf(stderr, "plain: ");
sshbuf_dump(state->outgoing_packet, stderr);
#endif
if (comp && comp->enabled) {
len = sshbuf_len(state->outgoing_packet);
/* skip header, compress only payload */
if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0)
goto out;
sshbuf_reset(state->compression_buffer);
if ((r = compress_buffer(ssh, state->outgoing_packet,
state->compression_buffer)) != 0)
goto out;
sshbuf_reset(state->outgoing_packet);
if ((r = sshbuf_put(state->outgoing_packet,
"\0\0\0\0\0", 5)) != 0 ||
(r = sshbuf_putb(state->outgoing_packet,
state->compression_buffer)) != 0)
goto out;
DBG(debug("compression: raw %d compressed %zd", len,
sshbuf_len(state->outgoing_packet)));
}
/* sizeof (packet_len + pad_len + payload) */
len = sshbuf_len(state->outgoing_packet);
/*
* calc size of padding, alloc space, get random data,
* minimum padding is 4 bytes
*/
len -= aadlen; /* packet length is not encrypted for EtM modes */
padlen = block_size - (len % block_size);
if (padlen < 4)
padlen += block_size;
if (state->extra_pad) {
tmp = state->extra_pad;
state->extra_pad =
ROUNDUP(state->extra_pad, block_size);
/* check if roundup overflowed */
if (state->extra_pad < tmp)
return SSH_ERR_INVALID_ARGUMENT;
tmp = (len + padlen) % state->extra_pad;
/* Check whether pad calculation below will underflow */
if (tmp > state->extra_pad)
return SSH_ERR_INVALID_ARGUMENT;
pad = state->extra_pad - tmp;
DBG(debug3_f("adding %d (len %d padlen %d extra_pad %d)",
pad, len, padlen, state->extra_pad));
tmp = padlen;
padlen += pad;
/* Check whether padlen calculation overflowed */
if (padlen < tmp)
return SSH_ERR_INVALID_ARGUMENT; /* overflow */
state->extra_pad = 0;
}
if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0)
goto out;
if (enc && !cipher_ctx_is_plaintext(state->send_context)) {
/* random padding */
arc4random_buf(cp, padlen);
} else {
/* clear padding */
explicit_bzero(cp, padlen);
}
/* sizeof (packet_len + pad_len + payload + padding) */
len = sshbuf_len(state->outgoing_packet);
cp = sshbuf_mutable_ptr(state->outgoing_packet);
if (cp == NULL) {
r = SSH_ERR_INTERNAL_ERROR;
goto out;
}
/* packet_length includes payload, padding and padding length field */
POKE_U32(cp, len - 4);
cp[4] = padlen;
DBG(debug("send: len %d (includes padlen %d, aadlen %d)",
len, padlen, aadlen));
/* compute MAC over seqnr and packet(length fields, payload, padding) */
if (mac && mac->enabled && !mac->etm) {
if ((r = mac_compute(mac, state->p_send.seqnr,
sshbuf_ptr(state->outgoing_packet), len,
macbuf, sizeof(macbuf))) != 0)
goto out;
DBG(debug("done calc MAC out #%d", state->p_send.seqnr));
}
/* encrypt packet and append to output buffer. */
if ((r = sshbuf_reserve(state->output,
sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0)
goto out;
if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp,
sshbuf_ptr(state->outgoing_packet),
len - aadlen, aadlen, authlen)) != 0)
goto out;
/* append unencrypted MAC */
if (mac && mac->enabled) {
if (mac->etm) {
/* EtM: compute mac over aadlen + cipher text */
if ((r = mac_compute(mac, state->p_send.seqnr,
cp, len, macbuf, sizeof(macbuf))) != 0)
goto out;
DBG(debug("done calc MAC(EtM) out #%d",
state->p_send.seqnr));
}
if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
goto out;
}
#ifdef PACKET_DEBUG
fprintf(stderr, "encrypted: ");
sshbuf_dump(state->output, stderr);
#endif
/* increment sequence number for outgoing packets */
if (++state->p_send.seqnr == 0) {
if ((ssh->kex->flags & KEX_INITIAL) != 0) {
ssh_packet_disconnect(ssh, "outgoing sequence number "
"wrapped during initial key exchange");
}
logit("outgoing seqnr wraps around");
}
if (++state->p_send.packets == 0)
if (!(ssh->compat & SSH_BUG_NOREKEY))
return SSH_ERR_NEED_REKEY;
state->p_send.blocks += len / block_size;
state->p_send.bytes += len;
sshbuf_reset(state->outgoing_packet);
if (type == SSH2_MSG_NEWKEYS && ssh->kex->kex_strict) {
debug_f("resetting send seqnr %u", state->p_send.seqnr);
state->p_send.seqnr = 0;
}
if (type == SSH2_MSG_NEWKEYS)
r = ssh_set_newkeys(ssh, MODE_OUT);
else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side)
r = ssh_packet_enable_delayed_compress(ssh);
else
r = 0;
out:
return r;
}
/* returns non-zero if the specified packet type is usec by KEX */
static int
ssh_packet_type_is_kex(u_char type)
{
return
type >= SSH2_MSG_TRANSPORT_MIN &&
type <= SSH2_MSG_TRANSPORT_MAX &&
type != SSH2_MSG_SERVICE_REQUEST &&
type != SSH2_MSG_SERVICE_ACCEPT &&
type != SSH2_MSG_EXT_INFO;
}
int
ssh_packet_send2(struct ssh *ssh)
{
struct session_state *state = ssh->state;
struct packet *p;
u_char type;
int r, need_rekey;
if (sshbuf_len(state->outgoing_packet) < 6)
return SSH_ERR_INTERNAL_ERROR;
type = sshbuf_ptr(state->outgoing_packet)[5];
need_rekey = !ssh_packet_type_is_kex(type) &&
ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet));
/*
* During rekeying we can only send key exchange messages.
* Queue everything else.
*/
if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) {
if (need_rekey)
debug3_f("rekex triggered");
debug("enqueue packet: %u", type);
p = calloc(1, sizeof(*p));
if (p == NULL)
return SSH_ERR_ALLOC_FAIL;
p->type = type;
p->payload = state->outgoing_packet;
TAILQ_INSERT_TAIL(&state->outgoing, p, next);
state->outgoing_packet = sshbuf_new();
if (state->outgoing_packet == NULL)
return SSH_ERR_ALLOC_FAIL;
if (need_rekey) {
/*
* This packet triggered a rekey, so send the
* KEXINIT now.
* NB. reenters this function via kex_start_rekex().
*/
return kex_start_rekex(ssh);
}
return 0;
}
/* rekeying starts with sending KEXINIT */
if (type == SSH2_MSG_KEXINIT)
state->rekeying = 1;
if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
return r;
/* after a NEWKEYS message we can send the complete queue */
if (type == SSH2_MSG_NEWKEYS) {
state->rekeying = 0;
state->rekey_time = monotime();
while ((p = TAILQ_FIRST(&state->outgoing))) {
type = p->type;
/*
* If this packet triggers a rekex, then skip the
* remaining packets in the queue for now.
* NB. re-enters this function via kex_start_rekex.
*/
if (ssh_packet_need_rekeying(ssh,
sshbuf_len(p->payload))) {
debug3_f("queued packet triggered rekex");
return kex_start_rekex(ssh);
}
debug("dequeue packet: %u", type);
sshbuf_free(state->outgoing_packet);
state->outgoing_packet = p->payload;
TAILQ_REMOVE(&state->outgoing, p, next);
memset(p, 0, sizeof(*p));
free(p);
if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
return r;
}
}
return 0;
}
/*
* Waits until a packet has been received, and returns its type. Note that
* no other data is processed until this returns, so this function should not
* be used during the interactive session.
*/
int
ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
{
struct session_state *state = ssh->state;
int len, r, ms_remain = 0;
struct pollfd pfd;
char buf[8192];
struct timeval start;
struct timespec timespec, *timespecp = NULL;
DBG(debug("packet_read()"));
/*
* Since we are blocking, ensure that all written packets have
* been sent.
*/
if ((r = ssh_packet_write_wait(ssh)) != 0)
goto out;
/* Stay in the loop until we have received a complete packet. */
for (;;) {
/* Try to read a packet from the buffer. */
if ((r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p)) != 0)
break;
/* If we got a packet, return it. */
if (*typep != SSH_MSG_NONE)
break;
/*
* Otherwise, wait for some data to arrive, add it to the
* buffer, and try again.
*/
pfd.fd = state->connection_in;
pfd.events = POLLIN;
if (state->packet_timeout_ms > 0) {
ms_remain = state->packet_timeout_ms;
timespecp = &timespec;
}
/* Wait for some data to arrive. */
for (;;) {
if (state->packet_timeout_ms > 0) {
ms_to_timespec(&timespec, ms_remain);
monotime_tv(&start);
}
if ((r = ppoll(&pfd, 1, timespecp, NULL)) >= 0)
break;
if (errno != EAGAIN && errno != EINTR &&
errno != EWOULDBLOCK) {
r = SSH_ERR_SYSTEM_ERROR;
goto out;
}
if (state->packet_timeout_ms <= 0)
continue;
ms_subtract_diff(&start, &ms_remain);
if (ms_remain <= 0) {
r = 0;
break;
}
}
if (r == 0) {
r = SSH_ERR_CONN_TIMEOUT;
goto out;
}
/* Read data from the socket. */
len = read(state->connection_in, buf, sizeof(buf));
if (len == 0) {
r = SSH_ERR_CONN_CLOSED;
goto out;
}
if (len == -1) {
r = SSH_ERR_SYSTEM_ERROR;
goto out;
}
/* Append it to the buffer. */
if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0)
goto out;
}
out:
return r;
}
int
ssh_packet_read(struct ssh *ssh)
{
u_char type;
int r;
if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
fatal_fr(r, "read");
return type;
}
static int
ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
{
struct session_state *state = ssh->state;
const u_char *cp;
size_t need;
int r;
if (ssh->kex)
return SSH_ERR_INTERNAL_ERROR;
*typep = SSH_MSG_NONE;
cp = sshbuf_ptr(state->input);
if (state->packlen == 0) {
if (sshbuf_len(state->input) < 4 + 1)
return 0; /* packet is incomplete */
state->packlen = PEEK_U32(cp);
if (state->packlen < 4 + 1 ||
state->packlen > PACKET_MAX_SIZE)
return SSH_ERR_MESSAGE_INCOMPLETE;
}
need = state->packlen + 4;
if (sshbuf_len(state->input) < need)
return 0; /* packet is incomplete */
sshbuf_reset(state->incoming_packet);
if ((r = sshbuf_put(state->incoming_packet, cp + 4,
state->packlen)) != 0 ||
(r = sshbuf_consume(state->input, need)) != 0 ||
(r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 ||
(r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
return r;
if (ssh_packet_log_type(*typep))
debug3_f("type %u", *typep);
/* sshbuf_dump(state->incoming_packet, stderr); */
/* reset for next packet */
state->packlen = 0;
return r;
}
int
ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
{
struct session_state *state = ssh->state;
u_int padlen, need;
u_char *cp;
u_int maclen, aadlen = 0, authlen = 0, block_size;
struct sshenc *enc = NULL;
struct sshmac *mac = NULL;
struct sshcomp *comp = NULL;
int r;
if (state->mux)
return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p);
*typep = SSH_MSG_NONE;
if (state->packet_discard)
return 0;
if (state->newkeys[MODE_IN] != NULL) {
enc = &state->newkeys[MODE_IN]->enc;
mac = &state->newkeys[MODE_IN]->mac;
comp = &state->newkeys[MODE_IN]->comp;
/* disable mac for authenticated encryption */
if ((authlen = cipher_authlen(enc->cipher)) != 0)
mac = NULL;
}
maclen = mac && mac->enabled ? mac->mac_len : 0;
block_size = enc ? enc->block_size : 8;
aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
if (aadlen && state->packlen == 0) {
if (cipher_get_length(state->receive_context,
&state->packlen, state->p_read.seqnr,
sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0)
return 0;
if (state->packlen < 1 + 4 ||
state->packlen > PACKET_MAX_SIZE) {
#ifdef PACKET_DEBUG
sshbuf_dump(state->input, stderr);
#endif
logit("Bad packet length %u.", state->packlen);
if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
return r;
return SSH_ERR_CONN_CORRUPT;
}
sshbuf_reset(state->incoming_packet);
} else if (state->packlen == 0) {
/*
* check if input size is less than the cipher block size,
* decrypt first block and extract length of incoming packet
*/
if (sshbuf_len(state->input) < block_size)
return 0;
sshbuf_reset(state->incoming_packet);
if ((r = sshbuf_reserve(state->incoming_packet, block_size,
&cp)) != 0)
goto out;
if ((r = cipher_crypt(state->receive_context,
state->p_send.seqnr, cp, sshbuf_ptr(state->input),
block_size, 0, 0)) != 0)
goto out;
state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet));
if (state->packlen < 1 + 4 ||
state->packlen > PACKET_MAX_SIZE) {
#ifdef PACKET_DEBUG
fprintf(stderr, "input: \n");
sshbuf_dump(state->input, stderr);
fprintf(stderr, "incoming_packet: \n");
sshbuf_dump(state->incoming_packet, stderr);
#endif
logit("Bad packet length %u.", state->packlen);
return ssh_packet_start_discard(ssh, enc, mac, 0,
PACKET_MAX_SIZE);
}
if ((r = sshbuf_consume(state->input, block_size)) != 0)
goto out;
}
DBG(debug("input: packet len %u", state->packlen+4));
if (aadlen) {
/* only the payload is encrypted */
need = state->packlen;
} else {
/*
* the payload size and the payload are encrypted, but we
* have a partial packet of block_size bytes
*/
need = 4 + state->packlen - block_size;
}
DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d,"
" aadlen %d", block_size, need, maclen, authlen, aadlen));
if (need % block_size != 0) {
logit("padding error: need %d block %d mod %d",
need, block_size, need % block_size);
return ssh_packet_start_discard(ssh, enc, mac, 0,
PACKET_MAX_SIZE - block_size);
}
/*
* check if the entire packet has been received and
* decrypt into incoming_packet:
* 'aadlen' bytes are unencrypted, but authenticated.
* 'need' bytes are encrypted, followed by either
* 'authlen' bytes of authentication tag or
* 'maclen' bytes of message authentication code.
*/
if (sshbuf_len(state->input) < aadlen + need + authlen + maclen)
return 0; /* packet is incomplete */
#ifdef PACKET_DEBUG
fprintf(stderr, "read_poll enc/full: ");
sshbuf_dump(state->input, stderr);
#endif
/* EtM: check mac over encrypted input */
if (mac && mac->enabled && mac->etm) {
if ((r = mac_check(mac, state->p_read.seqnr,
sshbuf_ptr(state->input), aadlen + need,
sshbuf_ptr(state->input) + aadlen + need + authlen,
maclen)) != 0) {
if (r == SSH_ERR_MAC_INVALID)
logit("Corrupted MAC on input.");
goto out;
}
}
if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
&cp)) != 0)
goto out;
if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp,
sshbuf_ptr(state->input), need, aadlen, authlen)) != 0)
goto out;
if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0)
goto out;
if (mac && mac->enabled) {
/* Not EtM: check MAC over cleartext */
if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr,
sshbuf_ptr(state->incoming_packet),
sshbuf_len(state->incoming_packet),
sshbuf_ptr(state->input), maclen)) != 0) {
if (r != SSH_ERR_MAC_INVALID)
goto out;
logit("Corrupted MAC on input.");
if (need + block_size > PACKET_MAX_SIZE)
return SSH_ERR_INTERNAL_ERROR;
return ssh_packet_start_discard(ssh, enc, mac,
sshbuf_len(state->incoming_packet),
PACKET_MAX_SIZE - need - block_size);
}
/* Remove MAC from input buffer */
DBG(debug("MAC #%d ok", state->p_read.seqnr));
if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0)
goto out;
}
if (seqnr_p != NULL)
*seqnr_p = state->p_read.seqnr;
if (++state->p_read.seqnr == 0) {
if ((ssh->kex->flags & KEX_INITIAL) != 0) {
ssh_packet_disconnect(ssh, "incoming sequence number "
"wrapped during initial key exchange");
}
logit("incoming seqnr wraps around");
}
if (++state->p_read.packets == 0)
if (!(ssh->compat & SSH_BUG_NOREKEY))
return SSH_ERR_NEED_REKEY;
state->p_read.blocks += (state->packlen + 4) / block_size;
state->p_read.bytes += state->packlen + 4;
/* get padlen */
padlen = sshbuf_ptr(state->incoming_packet)[4];
DBG(debug("input: padlen %d", padlen));
if (padlen < 4) {
if ((r = sshpkt_disconnect(ssh,
"Corrupted padlen %d on input.", padlen)) != 0 ||
(r = ssh_packet_write_wait(ssh)) != 0)
return r;
return SSH_ERR_CONN_CORRUPT;
}
/* skip packet size + padlen, discard padding */
if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 ||
((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0))
goto out;
DBG(debug("input: len before de-compress %zd",
sshbuf_len(state->incoming_packet)));
if (comp && comp->enabled) {
sshbuf_reset(state->compression_buffer);
if ((r = uncompress_buffer(ssh, state->incoming_packet,
state->compression_buffer)) != 0)
goto out;
sshbuf_reset(state->incoming_packet);
if ((r = sshbuf_putb(state->incoming_packet,
state->compression_buffer)) != 0)
goto out;
DBG(debug("input: len after de-compress %zd",
sshbuf_len(state->incoming_packet)));
}
/*
* get packet type, implies consume.
* return length of payload (without type field)
*/
if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
goto out;
if (ssh_packet_log_type(*typep))
debug3("receive packet: type %u", *typep);
if (*typep < SSH2_MSG_MIN) {
if ((r = sshpkt_disconnect(ssh,
"Invalid ssh2 packet type: %d", *typep)) != 0 ||
(r = ssh_packet_write_wait(ssh)) != 0)
return r;
return SSH_ERR_PROTOCOL_ERROR;
}
if (state->hook_in != NULL &&
(r = state->hook_in(ssh, state->incoming_packet, typep,
state->hook_in_ctx)) != 0)
return r;
if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side)
r = ssh_packet_enable_delayed_compress(ssh);
else
r = 0;
#ifdef PACKET_DEBUG
fprintf(stderr, "read/plain[%d]:\r\n", *typep);
sshbuf_dump(state->incoming_packet, stderr);
#endif
/* reset for next packet */
state->packlen = 0;
if (*typep == SSH2_MSG_NEWKEYS && ssh->kex->kex_strict) {
debug_f("resetting read seqnr %u", state->p_read.seqnr);
state->p_read.seqnr = 0;
}
if ((r = ssh_packet_check_rekey(ssh)) != 0)
return r;
out:
return r;
}
int
ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
{
struct session_state *state = ssh->state;
u_int reason, seqnr;
int r;
u_char *msg;
const u_char *d;
size_t len;
for (;;) {
msg = NULL;
r = ssh_packet_read_poll2(ssh, typep, seqnr_p);
if (r != 0)
return r;
if (*typep == 0) {
/* no message ready */
return 0;
}
state->keep_alive_timeouts = 0;
DBG(debug("received packet type %d", *typep));
/* Always process disconnect messages */
if (*typep == SSH2_MSG_DISCONNECT) {
if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
(r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
return r;
/* Ignore normal client exit notifications */
do_log2(ssh->state->server_side &&
reason == SSH2_DISCONNECT_BY_APPLICATION ?
SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
"Received disconnect from %s port %d:"
"%u: %.400s", ssh_remote_ipaddr(ssh),
ssh_remote_port(ssh), reason, msg);
free(msg);
return SSH_ERR_DISCONNECTED;
}
/*
* Do not implicitly handle any messages here during initial
* KEX when in strict mode. They will be need to be allowed
* explicitly by the KEX dispatch table or they will generate
* protocol errors.
*/
if (ssh->kex != NULL &&
(ssh->kex->flags & KEX_INITIAL) && ssh->kex->kex_strict)
return 0;
/* Implicitly handle transport-level messages */
switch (*typep) {
case SSH2_MSG_IGNORE:
debug3("Received SSH2_MSG_IGNORE");
break;
case SSH2_MSG_DEBUG:
if ((r = sshpkt_get_u8(ssh, NULL)) != 0 ||
(r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
(r = sshpkt_get_string(ssh, NULL, NULL)) != 0) {
free(msg);
return r;
}
debug("Remote: %.900s", msg);
free(msg);
break;
case SSH2_MSG_UNIMPLEMENTED:
if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0)
return r;
debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
seqnr);
break;
case SSH2_MSG_PING:
if ((r = sshpkt_get_string_direct(ssh, &d, &len)) != 0)
return r;
DBG(debug("Received SSH2_MSG_PING len %zu", len));
if ((r = sshpkt_start(ssh, SSH2_MSG_PONG)) != 0 ||
(r = sshpkt_put_string(ssh, d, len)) != 0 ||
(r = sshpkt_send(ssh)) != 0)
return r;
break;
case SSH2_MSG_PONG:
if ((r = sshpkt_get_string_direct(ssh,
NULL, &len)) != 0)
return r;
DBG(debug("Received SSH2_MSG_PONG len %zu", len));
break;
default:
return 0;
}
}
}
/*
* Buffers the supplied input data. This is intended to be used together
* with packet_read_poll().
*/
int
ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len)
{
struct session_state *state = ssh->state;
int r;
if (state->packet_discard) {
state->keep_alive_timeouts = 0; /* ?? */
if (len >= state->packet_discard) {
if ((r = ssh_packet_stop_discard(ssh)) != 0)
return r;
}
state->packet_discard -= len;
return 0;
}
if ((r = sshbuf_put(state->input, buf, len)) != 0)
return r;
return 0;
}
/* Reads and buffers data from the specified fd */
int
ssh_packet_process_read(struct ssh *ssh, int fd)
{
struct session_state *state = ssh->state;
int r;
size_t rlen;
if ((r = sshbuf_read(fd, state->input, PACKET_MAX_SIZE, &rlen)) != 0)
return r;
if (state->packet_discard) {
if ((r = sshbuf_consume_end(state->input, rlen)) != 0)
return r;
state->keep_alive_timeouts = 0; /* ?? */
if (rlen >= state->packet_discard) {
if ((r = ssh_packet_stop_discard(ssh)) != 0)
return r;
}
state->packet_discard -= rlen;
return 0;
}
return 0;
}
int
ssh_packet_remaining(struct ssh *ssh)
{
return sshbuf_len(ssh->state->incoming_packet);
}
/*
* Sends a diagnostic message from the server to the client. This message
* can be sent at any time (but not while constructing another message). The
* message is printed immediately, but only if the client is being executed
* in verbose mode. These messages are primarily intended to ease debugging
* authentication problems. The length of the formatted message must not
* exceed 1024 bytes. This will automatically call ssh_packet_write_wait.
*/
void
ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...)
{
char buf[1024];
va_list args;
int r;
if ((ssh->compat & SSH_BUG_DEBUG))
return;
va_start(args, fmt);
vsnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
debug3("sending debug message: %s", buf);
if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 ||
(r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */
(r = sshpkt_put_cstring(ssh, buf)) != 0 ||
(r = sshpkt_put_cstring(ssh, "")) != 0 ||
(r = sshpkt_send(ssh)) != 0 ||
(r = ssh_packet_write_wait(ssh)) != 0)
fatal_fr(r, "send DEBUG");
}
void
sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l)
{
snprintf(s, l, "%.200s%s%s port %d",
ssh->log_preamble ? ssh->log_preamble : "",
ssh->log_preamble ? " " : "",
ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
}
/*
* Pretty-print connection-terminating errors and exit.
*/
static void
sshpkt_vfatal(struct ssh *ssh, int r, const char *fmt, va_list ap)
{
char *tag = NULL, remote_id[512];
int oerrno = errno;
sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
switch (r) {
case SSH_ERR_CONN_CLOSED:
ssh_packet_clear_keys(ssh);
logdie("Connection closed by %s", remote_id);
case SSH_ERR_CONN_TIMEOUT:
ssh_packet_clear_keys(ssh);
logdie("Connection %s %s timed out",
ssh->state->server_side ? "from" : "to", remote_id);
case SSH_ERR_DISCONNECTED:
ssh_packet_clear_keys(ssh);
logdie("Disconnected from %s", remote_id);
case SSH_ERR_SYSTEM_ERROR:
if (errno == ECONNRESET) {
ssh_packet_clear_keys(ssh);
logdie("Connection reset by %s", remote_id);
}
/* FALLTHROUGH */
case SSH_ERR_NO_CIPHER_ALG_MATCH:
case SSH_ERR_NO_MAC_ALG_MATCH:
case SSH_ERR_NO_COMPRESS_ALG_MATCH:
case SSH_ERR_NO_KEX_ALG_MATCH:
case SSH_ERR_NO_HOSTKEY_ALG_MATCH:
if (ssh->kex && ssh->kex->failed_choice) {
ssh_packet_clear_keys(ssh);
errno = oerrno;
logdie("Unable to negotiate with %s: %s. "
"Their offer: %s", remote_id, ssh_err(r),
ssh->kex->failed_choice);
}
/* FALLTHROUGH */
default:
if (vasprintf(&tag, fmt, ap) == -1) {
ssh_packet_clear_keys(ssh);
logdie_f("could not allocate failure message");
}
ssh_packet_clear_keys(ssh);
errno = oerrno;
logdie_r(r, "%s%sConnection %s %s",
tag != NULL ? tag : "", tag != NULL ? ": " : "",
ssh->state->server_side ? "from" : "to", remote_id);
}
}
void
sshpkt_fatal(struct ssh *ssh, int r, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
sshpkt_vfatal(ssh, r, fmt, ap);
/* NOTREACHED */
va_end(ap);
logdie_f("should have exited");
}
/*
* Logs the error plus constructs and sends a disconnect packet, closes the
* connection, and exits. This function never returns. The error message
* should not contain a newline. The length of the formatted message must
* not exceed 1024 bytes.
*/
void
ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...)
{
char buf[1024], remote_id[512];
va_list args;
static int disconnecting = 0;
int r;
if (disconnecting) /* Guard against recursive invocations. */
fatal("packet_disconnect called recursively.");
disconnecting = 1;
/*
* Format the message. Note that the caller must make sure the
* message is of limited size.
*/
sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
va_start(args, fmt);
vsnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
/* Display the error locally */
logit("Disconnecting %s: %.100s", remote_id, buf);
/*
* Send the disconnect message to the other side, and wait
* for it to get sent.
*/
if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0)
sshpkt_fatal(ssh, r, "%s", __func__);
if ((r = ssh_packet_write_wait(ssh)) != 0)
sshpkt_fatal(ssh, r, "%s", __func__);
/* Close the connection. */
ssh_packet_close(ssh);
cleanup_exit(255);
}
/*
* Checks if there is any buffered output, and tries to write some of
* the output.
*/
int
ssh_packet_write_poll(struct ssh *ssh)
{
struct session_state *state = ssh->state;
int len = sshbuf_len(state->output);
int r;
if (len > 0) {
len = write(state->connection_out,
sshbuf_ptr(state->output), len);
if (len == -1) {
if (errno == EINTR || errno == EAGAIN ||
errno == EWOULDBLOCK)
return 0;
return SSH_ERR_SYSTEM_ERROR;
}
if (len == 0)
return SSH_ERR_CONN_CLOSED;
if ((r = sshbuf_consume(state->output, len)) != 0)
return r;
}
return 0;
}
/*
* Calls packet_write_poll repeatedly until all pending output data has been
* written.
*/
int
ssh_packet_write_wait(struct ssh *ssh)
{
int ret, r, ms_remain = 0;
struct timeval start;
struct timespec timespec, *timespecp = NULL;
struct session_state *state = ssh->state;
struct pollfd pfd;
if ((r = ssh_packet_write_poll(ssh)) != 0)
return r;
while (ssh_packet_have_data_to_write(ssh)) {
pfd.fd = state->connection_out;
pfd.events = POLLOUT;
if (state->packet_timeout_ms > 0) {
ms_remain = state->packet_timeout_ms;
timespecp = &timespec;
}
for (;;) {
if (state->packet_timeout_ms > 0) {
ms_to_timespec(&timespec, ms_remain);
monotime_tv(&start);
}
if ((ret = ppoll(&pfd, 1, timespecp, NULL)) >= 0)
break;
if (errno != EAGAIN && errno != EINTR &&
errno != EWOULDBLOCK)
break;
if (state->packet_timeout_ms <= 0)
continue;
ms_subtract_diff(&start, &ms_remain);
if (ms_remain <= 0) {
ret = 0;
break;
}
}
if (ret == 0)
return SSH_ERR_CONN_TIMEOUT;
if ((r = ssh_packet_write_poll(ssh)) != 0)
return r;
}
return 0;
}
/* Returns true if there is buffered data to write to the connection. */
int
ssh_packet_have_data_to_write(struct ssh *ssh)
{
return sshbuf_len(ssh->state->output) != 0;
}
/* Returns true if there is not too much data to write to the connection. */
int
ssh_packet_not_very_much_data_to_write(struct ssh *ssh)
{
if (ssh->state->interactive_mode)
return sshbuf_len(ssh->state->output) < 16384;
else
return sshbuf_len(ssh->state->output) < 128 * 1024;
}
/*
* returns true when there are at most a few keystrokes of data to write
* and the connection is in interactive mode.
*/
int
ssh_packet_interactive_data_to_write(struct ssh *ssh)
{
return ssh->state->interactive_mode &&
sshbuf_len(ssh->state->output) < 256;
}
void
ssh_packet_set_tos(struct ssh *ssh, int tos)
{
if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX)
return;
set_sock_tos(ssh->state->connection_in, tos);
}
/* Informs that the current session is interactive. Sets IP flags for that. */
void
ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk)
{
struct session_state *state = ssh->state;
if (state->set_interactive_called)
return;
state->set_interactive_called = 1;
/* Record that we are in interactive mode. */
state->interactive_mode = interactive;
/* Only set socket options if using a socket. */
if (!ssh_packet_connection_is_on_socket(ssh))
return;
set_nodelay(state->connection_in);
ssh_packet_set_tos(ssh, interactive ? qos_interactive : qos_bulk);
}
/* Returns true if the current connection is interactive. */
int
ssh_packet_is_interactive(struct ssh *ssh)
{
return ssh->state->interactive_mode;
}
int
ssh_packet_set_maxsize(struct ssh *ssh, u_int s)
{
struct session_state *state = ssh->state;
if (state->set_maxsize_called) {
logit_f("called twice: old %d new %d",
state->max_packet_size, s);
return -1;
}
if (s < 4 * 1024 || s > 1024 * 1024) {
logit_f("bad size %d", s);
return -1;
}
state->set_maxsize_called = 1;
debug_f("setting to %d", s);
state->max_packet_size = s;
return s;
}
int
ssh_packet_inc_alive_timeouts(struct ssh *ssh)
{
return ++ssh->state->keep_alive_timeouts;
}
void
ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka)
{
ssh->state->keep_alive_timeouts = ka;
}
u_int
ssh_packet_get_maxsize(struct ssh *ssh)
{
return ssh->state->max_packet_size;
}
void
ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds)
{
debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes,
(unsigned int)seconds);
ssh->state->rekey_limit = bytes;
ssh->state->rekey_interval = seconds;
}
time_t
ssh_packet_get_rekey_timeout(struct ssh *ssh)
{
time_t seconds;
seconds = ssh->state->rekey_time + ssh->state->rekey_interval -
monotime();
return (seconds <= 0 ? 1 : seconds);
}
void
ssh_packet_set_server(struct ssh *ssh)
{
ssh->state->server_side = 1;
ssh->kex->server = 1; /* XXX unify? */
}
void
ssh_packet_set_authenticated(struct ssh *ssh)
{
ssh->state->after_authentication = 1;
}
void *
ssh_packet_get_input(struct ssh *ssh)
{
return (void *)ssh->state->input;
}
void *
ssh_packet_get_output(struct ssh *ssh)
{
return (void *)ssh->state->output;
}
/* Reset after_authentication and reset compression in post-auth privsep */
static int
ssh_packet_set_postauth(struct ssh *ssh)
{
int r;
debug_f("called");
/* This was set in net child, but is not visible in user child */
ssh->state->after_authentication = 1;
ssh->state->rekeying = 0;
if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0)
return r;
return 0;
}
/* Packet state (de-)serialization for privsep */
/* turn kex into a blob for packet state serialization */
static int
kex_to_blob(struct sshbuf *m, struct kex *kex)
{
int r;
if ((r = sshbuf_put_u32(m, kex->we_need)) != 0 ||
(r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 ||
(r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 ||
(r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 ||
(r = sshbuf_put_u32(m, kex->kex_type)) != 0 ||
(r = sshbuf_put_u32(m, kex->kex_strict)) != 0 ||
(r = sshbuf_put_stringb(m, kex->my)) != 0 ||
(r = sshbuf_put_stringb(m, kex->peer)) != 0 ||
(r = sshbuf_put_stringb(m, kex->client_version)) != 0 ||
(r = sshbuf_put_stringb(m, kex->server_version)) != 0 ||
(r = sshbuf_put_stringb(m, kex->session_id)) != 0 ||
(r = sshbuf_put_u32(m, kex->flags)) != 0)
return r;
return 0;
}
/* turn key exchange results into a blob for packet state serialization */
static int
newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode)
{
struct sshbuf *b;
struct sshcipher_ctx *cc;
struct sshcomp *comp;
struct sshenc *enc;
struct sshmac *mac;
struct newkeys *newkey;
int r;
if ((newkey = ssh->state->newkeys[mode]) == NULL)
return SSH_ERR_INTERNAL_ERROR;
enc = &newkey->enc;
mac = &newkey->mac;
comp = &newkey->comp;
cc = (mode == MODE_OUT) ? ssh->state->send_context :
ssh->state->receive_context;
if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0)
return r;
if ((b = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshbuf_put_cstring(b, enc->name)) != 0 ||
(r = sshbuf_put_u32(b, enc->enabled)) != 0 ||
(r = sshbuf_put_u32(b, enc->block_size)) != 0 ||
(r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 ||
(r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0)
goto out;
if (cipher_authlen(enc->cipher) == 0) {
if ((r = sshbuf_put_cstring(b, mac->name)) != 0 ||
(r = sshbuf_put_u32(b, mac->enabled)) != 0 ||
(r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0)
goto out;
}
if ((r = sshbuf_put_u32(b, comp->type)) != 0 ||
(r = sshbuf_put_cstring(b, comp->name)) != 0)
goto out;
r = sshbuf_put_stringb(m, b);
out:
sshbuf_free(b);
return r;
}
/* serialize packet state into a blob */
int
ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m)
{
struct session_state *state = ssh->state;
int r;
if ((r = kex_to_blob(m, ssh->kex)) != 0 ||
(r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 ||
(r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 ||
(r = sshbuf_put_u64(m, state->rekey_limit)) != 0 ||
(r = sshbuf_put_u32(m, state->rekey_interval)) != 0 ||
(r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 ||
(r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 ||
(r = sshbuf_put_u32(m, state->p_send.packets)) != 0 ||
(r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 ||
(r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 ||
(r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 ||
(r = sshbuf_put_u32(m, state->p_read.packets)) != 0 ||
(r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 ||
(r = sshbuf_put_stringb(m, state->input)) != 0 ||
(r = sshbuf_put_stringb(m, state->output)) != 0)
return r;
return 0;
}
/* restore key exchange results from blob for packet state de-serialization */
static int
newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode)
{
struct sshbuf *b = NULL;
struct sshcomp *comp;
struct sshenc *enc;
struct sshmac *mac;
struct newkeys *newkey = NULL;
size_t keylen, ivlen, maclen;
int r;
if ((newkey = calloc(1, sizeof(*newkey))) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshbuf_froms(m, &b)) != 0)
goto out;
#ifdef DEBUG_PK
sshbuf_dump(b, stderr);
#endif
enc = &newkey->enc;
mac = &newkey->mac;
comp = &newkey->comp;
if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 ||
(r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 ||
(r = sshbuf_get_u32(b, &enc->block_size)) != 0 ||
(r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 ||
(r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0)
goto out;
if ((enc->cipher = cipher_by_name(enc->name)) == NULL) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
if (cipher_authlen(enc->cipher) == 0) {
if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0)
goto out;
if ((r = mac_setup(mac, mac->name)) != 0)
goto out;
if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 ||
(r = sshbuf_get_string(b, &mac->key, &maclen)) != 0)
goto out;
if (maclen > mac->key_len) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
mac->key_len = maclen;
}
if ((r = sshbuf_get_u32(b, &comp->type)) != 0 ||
(r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0)
goto out;
if (sshbuf_len(b) != 0) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
enc->key_len = keylen;
enc->iv_len = ivlen;
ssh->kex->newkeys[mode] = newkey;
newkey = NULL;
r = 0;
out:
free(newkey);
sshbuf_free(b);
return r;
}
/* restore kex from blob for packet state de-serialization */
static int
kex_from_blob(struct sshbuf *m, struct kex **kexp)
{
struct kex *kex;
int r;
if ((kex = kex_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshbuf_get_u32(m, &kex->we_need)) != 0 ||
(r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 ||
(r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 ||
(r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 ||
(r = sshbuf_get_u32(m, &kex->kex_type)) != 0 ||
(r = sshbuf_get_u32(m, &kex->kex_strict)) != 0 ||
(r = sshbuf_get_stringb(m, kex->my)) != 0 ||
(r = sshbuf_get_stringb(m, kex->peer)) != 0 ||
(r = sshbuf_get_stringb(m, kex->client_version)) != 0 ||
(r = sshbuf_get_stringb(m, kex->server_version)) != 0 ||
(r = sshbuf_get_stringb(m, kex->session_id)) != 0 ||
(r = sshbuf_get_u32(m, &kex->flags)) != 0)
goto out;
kex->server = 1;
kex->done = 1;
r = 0;
out:
if (r != 0 || kexp == NULL) {
kex_free(kex);
if (kexp != NULL)
*kexp = NULL;
} else {
kex_free(*kexp);
*kexp = kex;
}
return r;
}
/*
* Restore packet state from content of blob 'm' (de-serialization).
* Note that 'm' will be partially consumed on parsing or any other errors.
*/
int
ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m)
{
struct session_state *state = ssh->state;
const u_char *input, *output;
size_t ilen, olen;
int r;
if ((r = kex_from_blob(m, &ssh->kex)) != 0 ||
(r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 ||
(r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 ||
(r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 ||
(r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 ||
(r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 ||
(r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 ||
(r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 ||
(r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 ||
(r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 ||
(r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 ||
(r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 ||
(r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0)
return r;
/*
* We set the time here so that in post-auth privsep child we
* count from the completion of the authentication.
*/
state->rekey_time = monotime();
/* XXX ssh_set_newkeys overrides p_read.packets? XXX */
if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 ||
(r = ssh_set_newkeys(ssh, MODE_OUT)) != 0)
return r;
if ((r = ssh_packet_set_postauth(ssh)) != 0)
return r;
sshbuf_reset(state->input);
sshbuf_reset(state->output);
if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 ||
(r = sshbuf_get_string_direct(m, &output, &olen)) != 0 ||
(r = sshbuf_put(state->input, input, ilen)) != 0 ||
(r = sshbuf_put(state->output, output, olen)) != 0)
return r;
if (sshbuf_len(m))
return SSH_ERR_INVALID_FORMAT;
debug3_f("done");
return 0;
}
/* NEW API */
/* put data to the outgoing packet */
int
sshpkt_put(struct ssh *ssh, const void *v, size_t len)
{
return sshbuf_put(ssh->state->outgoing_packet, v, len);
}
int
sshpkt_putb(struct ssh *ssh, const struct sshbuf *b)
{
return sshbuf_putb(ssh->state->outgoing_packet, b);
}
int
sshpkt_put_u8(struct ssh *ssh, u_char val)
{
return sshbuf_put_u8(ssh->state->outgoing_packet, val);
}
int
sshpkt_put_u32(struct ssh *ssh, u_int32_t val)
{
return sshbuf_put_u32(ssh->state->outgoing_packet, val);
}
int
sshpkt_put_u64(struct ssh *ssh, u_int64_t val)
{
return sshbuf_put_u64(ssh->state->outgoing_packet, val);
}
int
sshpkt_put_string(struct ssh *ssh, const void *v, size_t len)
{
return sshbuf_put_string(ssh->state->outgoing_packet, v, len);
}
int
sshpkt_put_cstring(struct ssh *ssh, const void *v)
{
return sshbuf_put_cstring(ssh->state->outgoing_packet, v);
}
int
sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v)
{
return sshbuf_put_stringb(ssh->state->outgoing_packet, v);
}
int
sshpkt_getb_froms(struct ssh *ssh, struct sshbuf **valp)
{
return sshbuf_froms(ssh->state->incoming_packet, valp);
}
#ifdef WITH_OPENSSL
#ifdef OPENSSL_HAS_ECC
int
sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g)
{
return sshbuf_put_ec(ssh->state->outgoing_packet, v, g);
}
#endif /* OPENSSL_HAS_ECC */
int
sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v)
{
return sshbuf_put_bignum2(ssh->state->outgoing_packet, v);
}
#endif /* WITH_OPENSSL */
/* fetch data from the incoming packet */
int
sshpkt_get(struct ssh *ssh, void *valp, size_t len)
{
return sshbuf_get(ssh->state->incoming_packet, valp, len);
}
int
sshpkt_get_u8(struct ssh *ssh, u_char *valp)
{
return sshbuf_get_u8(ssh->state->incoming_packet, valp);
}
int
sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp)
{
return sshbuf_get_u32(ssh->state->incoming_packet, valp);
}
int
sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp)
{
return sshbuf_get_u64(ssh->state->incoming_packet, valp);
}
int
sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp)
{
return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp);
}
int
sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
{
return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp);
}
int
sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
{
return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp);
}
int
sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp)
{
return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp);
}
#ifdef WITH_OPENSSL
#ifdef OPENSSL_HAS_ECC
int
sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g)
{
return sshbuf_get_ec(ssh->state->incoming_packet, v, g);
}
#endif /* OPENSSL_HAS_ECC */
int
sshpkt_get_bignum2(struct ssh *ssh, BIGNUM **valp)
{
return sshbuf_get_bignum2(ssh->state->incoming_packet, valp);
}
#endif /* WITH_OPENSSL */
int
sshpkt_get_end(struct ssh *ssh)
{
if (sshbuf_len(ssh->state->incoming_packet) > 0)
return SSH_ERR_UNEXPECTED_TRAILING_DATA;
return 0;
}
const u_char *
sshpkt_ptr(struct ssh *ssh, size_t *lenp)
{
if (lenp != NULL)
*lenp = sshbuf_len(ssh->state->incoming_packet);
return sshbuf_ptr(ssh->state->incoming_packet);
}
/* start a new packet */
int
sshpkt_start(struct ssh *ssh, u_char type)
{
u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */
DBG(debug("packet_start[%d]", type));
memset(buf, 0, sizeof(buf));
buf[sizeof(buf) - 1] = type;
sshbuf_reset(ssh->state->outgoing_packet);
return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf));
}
static int
ssh_packet_send_mux(struct ssh *ssh)
{
struct session_state *state = ssh->state;
u_char type, *cp;
size_t len;
int r;
if (ssh->kex)
return SSH_ERR_INTERNAL_ERROR;
len = sshbuf_len(state->outgoing_packet);
if (len < 6)
return SSH_ERR_INTERNAL_ERROR;
cp = sshbuf_mutable_ptr(state->outgoing_packet);
type = cp[5];
if (ssh_packet_log_type(type))
debug3_f("type %u", type);
/* drop everything, but the connection protocol */
if (type >= SSH2_MSG_CONNECTION_MIN &&
type <= SSH2_MSG_CONNECTION_MAX) {
POKE_U32(cp, len - 4);
if ((r = sshbuf_putb(state->output,
state->outgoing_packet)) != 0)
return r;
/* sshbuf_dump(state->output, stderr); */
}
sshbuf_reset(state->outgoing_packet);
return 0;
}
/*
* 9.2. Ignored Data Message
*
* byte SSH_MSG_IGNORE
* string data
*
* All implementations MUST understand (and ignore) this message at any
* time (after receiving the protocol version). No implementation is
* required to send them. This message can be used as an additional
* protection measure against advanced traffic analysis techniques.
*/
int
sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes)
{
u_int32_t rnd = 0;
int r;
u_int i;
if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 ||
(r = sshpkt_put_u32(ssh, nbytes)) != 0)
return r;
for (i = 0; i < nbytes; i++) {
if (i % 4 == 0)
rnd = arc4random();
if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0)
return r;
rnd >>= 8;
}
return 0;
}
/* send it */
int
sshpkt_send(struct ssh *ssh)
{
if (ssh->state && ssh->state->mux)
return ssh_packet_send_mux(ssh);
return ssh_packet_send2(ssh);
}
int
sshpkt_disconnect(struct ssh *ssh, const char *fmt,...)
{
char buf[1024];
va_list args;
int r;
va_start(args, fmt);
vsnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
debug2_f("sending SSH2_MSG_DISCONNECT: %s", buf);
if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
(r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 ||
(r = sshpkt_put_cstring(ssh, buf)) != 0 ||
(r = sshpkt_put_cstring(ssh, "")) != 0 ||
(r = sshpkt_send(ssh)) != 0)
return r;
return 0;
}
/* roundup current message to pad bytes */
int
sshpkt_add_padding(struct ssh *ssh, u_char pad)
{
ssh->state->extra_pad = pad;
return 0;
}
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