X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/f6be21a0be819e00d2f88fb1b8b9041ca6985272..040d6b1f7000ee8e36f8d0a21ea82a5f88acb7a5:/packet.c diff --git a/packet.c b/packet.c index fe3eea09..4ded17fa 100644 --- a/packet.c +++ b/packet.c @@ -1,3 +1,4 @@ +/* $OpenBSD: packet.c,v 1.158 2008/11/21 15:47:38 markus Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland @@ -37,26 +38,39 @@ */ #include "includes.h" -RCSID("$OpenBSD: packet.c,v 1.113 2004/05/11 19:01:43 deraadt Exp $"); - + +#include #include "openbsd-compat/sys-queue.h" +#include +#include +#ifdef HAVE_SYS_TIME_H +# include +#endif + +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include #include "xmalloc.h" #include "buffer.h" #include "packet.h" -#include "bufaux.h" #include "crc32.h" -#include "getput.h" - #include "compress.h" #include "deattack.h" #include "channels.h" - #include "compat.h" #include "ssh1.h" #include "ssh2.h" - #include "cipher.h" +#include "key.h" #include "kex.h" #include "mac.h" #include "log.h" @@ -116,12 +130,24 @@ static int initialized = 0; /* Set to true if the connection is interactive. */ static int interactive_mode = 0; +/* Set to true if we are the server side. */ +static int server_side = 0; + +/* Set to true if we are authenticated. */ +static int after_authentication = 0; + +int keep_alive_timeouts = 0; + +/* Set to the maximum time that we will wait to send or receive a packet */ +static int packet_timeout_ms = -1; + /* Session key information for Encryption and MAC */ Newkeys *newkeys[MODE_MAX]; static struct packet_state { u_int32_t seqnr; u_int32_t packets; u_int64_t blocks; + u_int64_t bytes; } p_read, p_send; static u_int64_t max_blocks_in, max_blocks_out; @@ -166,9 +192,23 @@ packet_set_connection(int fd_in, int fd_out) buffer_init(&outgoing_packet); buffer_init(&incoming_packet); TAILQ_INIT(&outgoing); + p_send.packets = p_read.packets = 0; } } +void +packet_set_timeout(int timeout, int count) +{ + if (timeout == 0 || count == 0) { + packet_timeout_ms = -1; + return; + } + if ((INT_MAX / 1000) / count < timeout) + packet_timeout_ms = INT_MAX; + else + packet_timeout_ms = timeout * count * 1000; +} + /* Returns 1 if remote host is connected via socket, 0 if not. */ int @@ -252,6 +292,7 @@ packet_get_keyiv_len(int mode) return (cipher_get_keyiv_len(cc)); } + void packet_set_iv(int mode, u_char *dat) { @@ -264,6 +305,7 @@ packet_set_iv(int mode, u_char *dat) cipher_set_keyiv(cc, dat); } + int packet_get_ssh1_cipher(void) { @@ -271,18 +313,25 @@ packet_get_ssh1_cipher(void) } void -packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets) +packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets, + u_int64_t *bytes) { struct packet_state *state; state = (mode == MODE_IN) ? &p_read : &p_send; - *seqnr = state->seqnr; - *blocks = state->blocks; - *packets = state->packets; + if (seqnr) + *seqnr = state->seqnr; + if (blocks) + *blocks = state->blocks; + if (packets) + *packets = state->packets; + if (bytes) + *bytes = state->bytes; } void -packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets) +packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets, + u_int64_t bytes) { struct packet_state *state; @@ -290,6 +339,7 @@ packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets) state->seqnr = seqnr; state->blocks = blocks; state->packets = packets; + state->bytes = bytes; } /* returns 1 if connection is via ipv4 */ @@ -319,13 +369,10 @@ void packet_set_nonblocking(void) { /* Set the socket into non-blocking mode. */ - if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0) - error("fcntl O_NONBLOCK: %.100s", strerror(errno)); + set_nonblock(connection_in); - if (connection_out != connection_in) { - if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0) - error("fcntl O_NONBLOCK: %.100s", strerror(errno)); - } + if (connection_out != connection_in) + set_nonblock(connection_out); } /* Returns the socket used for reading. */ @@ -468,31 +515,37 @@ packet_put_char(int value) buffer_append(&outgoing_packet, &ch, 1); } + void packet_put_int(u_int value) { buffer_put_int(&outgoing_packet, value); } + void packet_put_string(const void *buf, u_int len) { buffer_put_string(&outgoing_packet, buf, len); } + void packet_put_cstring(const char *str) { buffer_put_cstring(&outgoing_packet, str); } + void packet_put_raw(const void *buf, u_int len) { buffer_append(&outgoing_packet, buf, len); } + void packet_put_bignum(BIGNUM * value) { buffer_put_bignum(&outgoing_packet, value); } + void packet_put_bignum2(BIGNUM * value) { @@ -510,7 +563,7 @@ packet_send1(void) u_char buf[8], *cp; int i, padding, len; u_int checksum; - u_int32_t rand = 0; + u_int32_t rnd = 0; /* * If using packet compression, compress the payload of the outgoing @@ -536,9 +589,9 @@ packet_send1(void) cp = buffer_ptr(&outgoing_packet); for (i = 0; i < padding; i++) { if (i % 4 == 0) - rand = arc4random(); - cp[7 - i] = rand & 0xff; - rand >>= 8; + rnd = arc4random(); + cp[7 - i] = rnd & 0xff; + rnd >>= 8; } } buffer_consume(&outgoing_packet, 8 - padding); @@ -546,7 +599,7 @@ packet_send1(void) /* Add check bytes. */ checksum = ssh_crc32(buffer_ptr(&outgoing_packet), buffer_len(&outgoing_packet)); - PUT_32BIT(buf, checksum); + put_u32(buf, checksum); buffer_append(&outgoing_packet, buf, 4); #ifdef PACKET_DEBUG @@ -555,7 +608,7 @@ packet_send1(void) #endif /* Append to output. */ - PUT_32BIT(buf, len); + put_u32(buf, len); buffer_append(&output, buf, 4); cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet), @@ -565,11 +618,12 @@ packet_send1(void) fprintf(stderr, "encrypted: "); buffer_dump(&output); #endif - + p_send.packets++; + p_send.bytes += len + buffer_len(&outgoing_packet); buffer_clear(&outgoing_packet); /* - * Note that the packet is now only buffered in output. It won\'t be + * Note that the packet is now only buffered in output. It won't be * actually sent until packet_write_wait or packet_write_poll is * called. */ @@ -583,18 +637,18 @@ set_newkeys(int mode) Comp *comp; CipherContext *cc; u_int64_t *max_blocks; - int encrypt; + int crypt_type; debug2("set_newkeys: mode %d", mode); if (mode == MODE_OUT) { cc = &send_context; - encrypt = CIPHER_ENCRYPT; + crypt_type = CIPHER_ENCRYPT; p_send.packets = p_send.blocks = 0; max_blocks = &max_blocks_out; } else { cc = &receive_context; - encrypt = CIPHER_DECRYPT; + crypt_type = CIPHER_DECRYPT; p_read.packets = p_read.blocks = 0; max_blocks = &max_blocks_in; } @@ -604,7 +658,7 @@ set_newkeys(int mode) enc = &newkeys[mode]->enc; mac = &newkeys[mode]->mac; comp = &newkeys[mode]->comp; - memset(mac->key, 0, mac->key_len); + mac_clear(mac); xfree(enc->name); xfree(enc->iv); xfree(enc->key); @@ -619,15 +673,18 @@ set_newkeys(int mode) enc = &newkeys[mode]->enc; mac = &newkeys[mode]->mac; comp = &newkeys[mode]->comp; - if (mac->md != NULL) + if (mac_init(mac) == 0) mac->enabled = 1; DBG(debug("cipher_init_context: %d", mode)); cipher_init(cc, enc->cipher, enc->key, enc->key_len, - enc->iv, enc->block_size, encrypt); + enc->iv, enc->block_size, crypt_type); /* Deleting the keys does not gain extra security */ /* memset(enc->iv, 0, enc->block_size); - memset(enc->key, 0, enc->key_len); */ - if (comp->type != 0 && comp->enabled == 0) { + memset(enc->key, 0, enc->key_len); + memset(mac->key, 0, mac->key_len); */ + if ((comp->type == COMP_ZLIB || + (comp->type == COMP_DELAYED && after_authentication)) && + comp->enabled == 0) { packet_init_compression(); if (mode == MODE_OUT) buffer_compress_init_send(6); @@ -647,6 +704,38 @@ set_newkeys(int mode) *max_blocks = MIN(*max_blocks, rekey_limit / enc->block_size); } +/* + * 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 void +packet_enable_delayed_compress(void) +{ + Comp *comp = NULL; + int mode; + + /* + * Remember that we are past the authentication step, so rekeying + * with COMP_DELAYED will turn on compression immediately. + */ + after_authentication = 1; + for (mode = 0; mode < MODE_MAX; mode++) { + /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ + if (newkeys[mode] == NULL) + continue; + comp = &newkeys[mode]->comp; + if (comp && !comp->enabled && comp->type == COMP_DELAYED) { + packet_init_compression(); + if (mode == MODE_OUT) + buffer_compress_init_send(6); + else + buffer_compress_init_recv(); + comp->enabled = 1; + } + } +} + /* * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) */ @@ -657,7 +746,7 @@ packet_send2_wrapped(void) u_char padlen, pad; u_int packet_length = 0; u_int i, len; - u_int32_t rand = 0; + u_int32_t rnd = 0; Enc *enc = NULL; Mac *mac = NULL; Comp *comp = NULL; @@ -716,9 +805,9 @@ packet_send2_wrapped(void) /* random padding */ for (i = 0; i < padlen; i++) { if (i % 4 == 0) - rand = arc4random(); - cp[i] = rand & 0xff; - rand >>= 8; + rnd = arc4random(); + cp[i] = rnd & 0xff; + rnd >>= 8; } } else { /* clear padding */ @@ -727,7 +816,7 @@ packet_send2_wrapped(void) /* packet_length includes payload, padding and padding length field */ packet_length = buffer_len(&outgoing_packet) - 4; cp = buffer_ptr(&outgoing_packet); - PUT_32BIT(cp, packet_length); + put_u32(cp, packet_length); cp[4] = padlen; DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); @@ -744,7 +833,7 @@ packet_send2_wrapped(void) buffer_len(&outgoing_packet)); /* append unencrypted MAC */ if (mac && mac->enabled) - buffer_append(&output, (char *)macbuf, mac->mac_len); + buffer_append(&output, macbuf, mac->mac_len); #ifdef PACKET_DEBUG fprintf(stderr, "encrypted: "); buffer_dump(&output); @@ -756,10 +845,13 @@ packet_send2_wrapped(void) if (!(datafellows & SSH_BUG_NOREKEY)) fatal("XXX too many packets with same key"); p_send.blocks += (packet_length + 4) / block_size; + p_send.bytes += packet_length + 4; buffer_clear(&outgoing_packet); if (type == SSH2_MSG_NEWKEYS) set_newkeys(MODE_OUT); + else if (type == SSH2_MSG_USERAUTH_SUCCESS && server_side) + packet_enable_delayed_compress(); } static void @@ -827,12 +919,14 @@ packet_send(void) int packet_read_seqnr(u_int32_t *seqnr_p) { - int type, len; + int type, len, ret, ms_remain; fd_set *setp; char buf[8192]; + struct timeval timeout, start, *timeoutp = NULL; + DBG(debug("packet_read()")); - setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) * + setp = (fd_set *)xcalloc(howmany(connection_in+1, NFDBITS), sizeof(fd_mask)); /* Since we are blocking, ensure that all written packets have been sent. */ @@ -861,11 +955,35 @@ packet_read_seqnr(u_int32_t *seqnr_p) sizeof(fd_mask)); FD_SET(connection_in, setp); + if (packet_timeout_ms > 0) { + ms_remain = packet_timeout_ms; + timeoutp = &timeout; + } /* Wait for some data to arrive. */ - while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 && - (errno == EAGAIN || errno == EINTR)) - ; - + for (;;) { + if (packet_timeout_ms != -1) { + ms_to_timeval(&timeout, ms_remain); + gettimeofday(&start, NULL); + } + if ((ret = select(connection_in + 1, setp, NULL, + NULL, timeoutp)) >= 0) + break; + if (errno != EAGAIN && errno != EINTR && + errno != EWOULDBLOCK) + break; + if (packet_timeout_ms == -1) + continue; + ms_subtract_diff(&start, &ms_remain); + if (ms_remain <= 0) { + ret = 0; + break; + } + } + if (ret == 0) { + logit("Connection to %.200s timed out while " + "waiting to read", get_remote_ipaddr()); + cleanup_exit(255); + } /* Read data from the socket. */ len = read(connection_in, buf, sizeof(buf)); if (len == 0) { @@ -923,7 +1041,7 @@ packet_read_poll1(void) return SSH_MSG_NONE; /* Get length of incoming packet. */ cp = buffer_ptr(&input); - len = GET_32BIT(cp); + len = get_u32(cp); if (len < 1 + 2 + 2 || len > 256 * 1024) packet_disconnect("Bad packet length %u.", len); padded_len = (len + 8) & ~7; @@ -942,9 +1060,16 @@ packet_read_poll1(void) * (C)1998 CORE-SDI, Buenos Aires Argentina * Ariel Futoransky(futo@core-sdi.com) */ - if (!receive_context.plaintext && - detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED) - packet_disconnect("crc32 compensation attack: network attack detected"); + if (!receive_context.plaintext) { + switch (detect_attack(buffer_ptr(&input), padded_len)) { + case DEATTACK_DETECTED: + packet_disconnect("crc32 compensation attack: " + "network attack detected"); + case DEATTACK_DOS_DETECTED: + packet_disconnect("deattack denial of " + "service detected"); + } + } /* Decrypt data to incoming_packet. */ buffer_clear(&incoming_packet); @@ -971,7 +1096,7 @@ packet_read_poll1(void) len, buffer_len(&incoming_packet)); cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4; - stored_checksum = GET_32BIT(cp); + stored_checksum = get_u32(cp); if (checksum != stored_checksum) packet_disconnect("Corrupted check bytes on input."); buffer_consume_end(&incoming_packet, 4); @@ -983,7 +1108,11 @@ packet_read_poll1(void) buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), buffer_len(&compression_buffer)); } + p_read.packets++; + p_read.bytes += padded_len + 4; type = buffer_get_char(&incoming_packet); + if (type < SSH_MSG_MIN || type > SSH_MSG_MAX) + packet_disconnect("Invalid ssh1 packet type: %d", type); return type; } @@ -993,7 +1122,7 @@ packet_read_poll2(u_int32_t *seqnr_p) static u_int packet_length = 0; u_int padlen, need; u_char *macbuf, *cp, type; - int maclen, block_size; + u_int maclen, block_size; Enc *enc = NULL; Mac *mac = NULL; Comp *comp = NULL; @@ -1018,12 +1147,13 @@ packet_read_poll2(u_int32_t *seqnr_p) cipher_crypt(&receive_context, cp, buffer_ptr(&input), block_size); cp = buffer_ptr(&incoming_packet); - packet_length = GET_32BIT(cp); + packet_length = get_u32(cp); if (packet_length < 1 + 4 || packet_length > 256 * 1024) { #ifdef PACKET_DEBUG buffer_dump(&incoming_packet); #endif - packet_disconnect("Bad packet length %u.", packet_length); + packet_disconnect("Bad packet length %-10u", + packet_length); } DBG(debug("input: packet len %u", packet_length+4)); buffer_consume(&input, block_size); @@ -1032,9 +1162,11 @@ packet_read_poll2(u_int32_t *seqnr_p) need = 4 + packet_length - block_size; DBG(debug("partial packet %d, need %d, maclen %d", block_size, need, maclen)); - if (need % block_size != 0) - fatal("padding error: need %d block %d mod %d", + if (need % block_size != 0) { + logit("padding error: need %d block %d mod %d", need, block_size, need % block_size); + packet_disconnect("Bad packet length %-10u", packet_length); + } /* * check if the entire packet has been received and * decrypt into incoming_packet @@ -1069,6 +1201,7 @@ packet_read_poll2(u_int32_t *seqnr_p) if (!(datafellows & SSH_BUG_NOREKEY)) fatal("XXX too many packets with same key"); p_read.blocks += (packet_length + 4) / block_size; + p_read.bytes += packet_length + 4; /* get padlen */ cp = buffer_ptr(&incoming_packet); @@ -1096,8 +1229,12 @@ packet_read_poll2(u_int32_t *seqnr_p) * return length of payload (without type field) */ type = buffer_get_char(&incoming_packet); + if (type < SSH2_MSG_MIN || type >= SSH2_MSG_LOCAL_MIN) + packet_disconnect("Invalid ssh2 packet type: %d", type); if (type == SSH2_MSG_NEWKEYS) set_newkeys(MODE_IN); + else if (type == SSH2_MSG_USERAUTH_SUCCESS && !server_side) + packet_enable_delayed_compress(); #ifdef PACKET_DEBUG fprintf(stderr, "read/plain[%d]:\r\n", type); buffer_dump(&incoming_packet); @@ -1117,10 +1254,13 @@ packet_read_poll_seqnr(u_int32_t *seqnr_p) for (;;) { if (compat20) { type = packet_read_poll2(seqnr_p); - if (type) + if (type) { + keep_alive_timeouts = 0; DBG(debug("received packet type %d", type)); + } switch (type) { case SSH2_MSG_IGNORE: + debug3("Received SSH2_MSG_IGNORE"); break; case SSH2_MSG_DEBUG: packet_get_char(); @@ -1145,7 +1285,6 @@ packet_read_poll_seqnr(u_int32_t *seqnr_p) break; default: return type; - break; } } else { type = packet_read_poll1(); @@ -1162,13 +1301,11 @@ packet_read_poll_seqnr(u_int32_t *seqnr_p) logit("Received disconnect from %s: %.400s", get_remote_ipaddr(), msg); cleanup_exit(255); - xfree(msg); break; default: if (type) DBG(debug("received packet type %d", type)); return type; - break; } } } @@ -1228,9 +1365,9 @@ packet_get_bignum2(BIGNUM * value) } void * -packet_get_raw(int *length_ptr) +packet_get_raw(u_int *length_ptr) { - int bytes = buffer_len(&incoming_packet); + u_int bytes = buffer_len(&incoming_packet); if (length_ptr != NULL) *length_ptr = bytes; @@ -1256,6 +1393,12 @@ packet_get_string(u_int *length_ptr) return buffer_get_string(&incoming_packet, length_ptr); } +void * +packet_get_string_ptr(u_int *length_ptr) +{ + return buffer_get_string_ptr(&incoming_packet, length_ptr); +} + /* * 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 @@ -1350,16 +1493,19 @@ packet_write_poll(void) if (len > 0) { len = write(connection_out, buffer_ptr(&output), len); - if (len <= 0) { - if (errno == EAGAIN) + if (len == -1) { + if (errno == EINTR || errno == EAGAIN || + errno == EWOULDBLOCK) return; - else - fatal("Write failed: %.100s", strerror(errno)); + fatal("Write failed: %.100s", strerror(errno)); } + if (len == 0) + fatal("Write connection closed"); buffer_consume(&output, len); } } + /* * Calls packet_write_poll repeatedly until all pending output data has been * written. @@ -1369,17 +1515,45 @@ void packet_write_wait(void) { fd_set *setp; + int ret, ms_remain; + struct timeval start, timeout, *timeoutp = NULL; - setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) * + setp = (fd_set *)xcalloc(howmany(connection_out + 1, NFDBITS), sizeof(fd_mask)); packet_write_poll(); while (packet_have_data_to_write()) { memset(setp, 0, howmany(connection_out + 1, NFDBITS) * sizeof(fd_mask)); FD_SET(connection_out, setp); - while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 && - (errno == EAGAIN || errno == EINTR)) - ; + + if (packet_timeout_ms > 0) { + ms_remain = packet_timeout_ms; + timeoutp = &timeout; + } + for (;;) { + if (packet_timeout_ms != -1) { + ms_to_timeval(&timeout, ms_remain); + gettimeofday(&start, NULL); + } + if ((ret = select(connection_out + 1, NULL, setp, + NULL, timeoutp)) >= 0) + break; + if (errno != EAGAIN && errno != EINTR && + errno != EWOULDBLOCK) + break; + if (packet_timeout_ms == -1) + continue; + ms_subtract_diff(&start, &ms_remain); + if (ms_remain <= 0) { + ret = 0; + break; + } + } + if (ret == 0) { + logit("Connection to %.200s timed out while " + "waiting to write", get_remote_ipaddr()); + cleanup_exit(255); + } packet_write_poll(); } xfree(setp); @@ -1438,8 +1612,7 @@ packet_set_interactive(int interactive) /* Only set socket options if using a socket. */ if (!packet_connection_is_on_socket()) return; - if (interactive) - set_nodelay(connection_in); + set_nodelay(connection_in); packet_set_tos(interactive); } @@ -1492,16 +1665,16 @@ packet_add_padding(u_char pad) void packet_send_ignore(int nbytes) { - u_int32_t rand = 0; + u_int32_t rnd = 0; int i; packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE); packet_put_int(nbytes); for (i = 0; i < nbytes; i++) { if (i % 4 == 0) - rand = arc4random(); - packet_put_char(rand & 0xff); - rand >>= 8; + rnd = arc4random(); + packet_put_char((u_char)rnd & 0xff); + rnd >>= 8; } } @@ -1523,3 +1696,15 @@ packet_set_rekey_limit(u_int32_t bytes) { rekey_limit = bytes; } + +void +packet_set_server(void) +{ + server_side = 1; +} + +void +packet_set_authenticated(void) +{ + after_authentication = 1; +}