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- /* $OpenBSD: packet.c,v 1.313 2023/12/18 14:45:17 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 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 = ×pec;
- }
- /* Wait for some data to arrive. */
- for (;;) {
- if (state->packet_timeout_ms > 0) {
- ms_to_timespec(×pec, 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 = ×pec;
- }
- for (;;) {
- if (state->packet_timeout_ms > 0) {
- ms_to_timespec(×pec, 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;
- }
|