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Diffstat (limited to 'packet.c')
| -rw-r--r-- | packet.c | 2719 |
1 files changed, 2719 insertions, 0 deletions
diff --git a/packet.c b/packet.c new file mode 100644 index 0000000..3f64d2d --- /dev/null +++ b/packet.c @@ -0,0 +1,2719 @@ +/* $OpenBSD: packet.c,v 1.308 2022/08/31 02:56:40 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_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) + 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) + 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; + 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. */ + r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p); + if (r != 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; +} + +/* + * Waits until a packet has been received, verifies that its type matches + * that given, and gives a fatal error and exits if there is a mismatch. + */ + +int +ssh_packet_read_expect(struct ssh *ssh, u_int expected_type) +{ + int r; + u_char type; + + if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0) + return r; + if (type != expected_type) { + if ((r = sshpkt_disconnect(ssh, + "Protocol error: expected packet type %d, got %d", + expected_type, type)) != 0) + return r; + return SSH_ERR_PROTOCOL_ERROR; + } + return 0; +} + +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) + 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 || *typep >= SSH2_MSG_LOCAL_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 ((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; + + for (;;) { + msg = NULL; + r = ssh_packet_read_poll2(ssh, typep, seqnr_p); + if (r != 0) + return r; + if (*typep) { + state->keep_alive_timeouts = 0; + DBG(debug("received packet type %d", *typep)); + } + 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_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; + case SSH2_MSG_UNIMPLEMENTED: + if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0) + return r; + debug("Received SSH2_MSG_UNIMPLEMENTED for %u", + seqnr); + 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 && 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; +} + +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_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_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); + + 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; +} |