=================================================================== RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/packet.c,v retrieving revision 1.38.2.8 retrieving revision 1.39 diff -u -r1.38.2.8 -r1.39 --- src/usr.bin/ssh/packet.c 2002/03/08 17:04:42 1.38.2.8 +++ src/usr.bin/ssh/packet.c 2000/12/06 22:58:15 1.39 @@ -13,7 +13,7 @@ * * * SSH2 packet format added by Markus Friedl. - * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. + * Copyright (c) 2000 Markus Friedl. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -37,12 +37,13 @@ */ #include "includes.h" -RCSID("$OpenBSD: packet.c,v 1.38.2.8 2002/03/08 17:04:42 brad Exp $"); +RCSID("$OpenBSD: packet.c,v 1.39 2000/12/06 22:58:15 markus Exp $"); #include "xmalloc.h" #include "buffer.h" #include "packet.h" #include "bufaux.h" +#include "ssh.h" #include "crc32.h" #include "getput.h" @@ -51,15 +52,15 @@ #include "channels.h" #include "compat.h" -#include "ssh1.h" #include "ssh2.h" +#include +#include +#include +#include "buffer.h" #include "cipher.h" #include "kex.h" -#include "mac.h" -#include "log.h" -#include "canohost.h" -#include "misc.h" +#include "hmac.h" #ifdef PACKET_DEBUG #define DBG(x) x @@ -76,8 +77,14 @@ static int connection_in = -1; static int connection_out = -1; +/* + * Cipher type. This value is only used to determine whether to pad the + * packets with zeroes or random data. + */ +static int cipher_type = SSH_CIPHER_NONE; + /* Protocol flags for the remote side. */ -static u_int remote_protocol_flags = 0; +static unsigned int remote_protocol_flags = 0; /* Encryption context for receiving data. This is only used for decryption. */ static CipherContext receive_context; @@ -99,7 +106,6 @@ /* Scratch buffer for packet compression/decompression. */ static Buffer compression_buffer; -static int compression_buffer_ready = 0; /* Flag indicating whether packet compression/decompression is enabled. */ static int packet_compression = 0; @@ -113,11 +119,40 @@ /* Set to true if the connection is interactive. */ static int interactive_mode = 0; +/* True if SSH2 packet format is used */ +int use_ssh2_packet_format = 0; + /* Session key information for Encryption and MAC */ -Newkeys *newkeys[MODE_MAX]; +Kex *kex = NULL; -/* roundup current message to extra_pad bytes */ -static u_char extra_pad = 0; +void +packet_set_kex(Kex *k) +{ + if( k->mac[MODE_IN ].key == NULL || + k->enc[MODE_IN ].key == NULL || + k->enc[MODE_IN ].iv == NULL || + k->mac[MODE_OUT].key == NULL || + k->enc[MODE_OUT].key == NULL || + k->enc[MODE_OUT].iv == NULL) + fatal("bad KEX"); + kex = k; +} +void +clear_enc_keys(Enc *enc, int len) +{ + memset(enc->iv, 0, len); + memset(enc->key, 0, len); + xfree(enc->iv); + xfree(enc->key); + enc->iv = NULL; + enc->key = NULL; +} +void +packet_set_ssh2_format(void) +{ + DBG(debug("use_ssh2_packet_format")); + use_ssh2_packet_format = 1; +} /* * Sets the descriptors used for communication. Disables encryption until @@ -131,9 +166,9 @@ fatal("packet_set_connection: cannot load cipher 'none'"); connection_in = fd_in; connection_out = fd_out; - cipher_init(&send_context, none, "", 0, NULL, 0, CIPHER_ENCRYPT); - cipher_init(&receive_context, none, "", 0, NULL, 0, CIPHER_DECRYPT); - newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL; + cipher_type = SSH_CIPHER_NONE; + cipher_init(&send_context, none, (unsigned char *) "", 0, NULL, 0); + cipher_init(&receive_context, none, (unsigned char *) "", 0, NULL, 0); if (!initialized) { initialized = 1; buffer_init(&input); @@ -148,7 +183,7 @@ /* Returns 1 if remote host is connected via socket, 0 if not. */ int -packet_connection_is_on_socket(void) +packet_connection_is_on_socket() { struct sockaddr_storage from, to; socklen_t fromlen, tolen; @@ -174,7 +209,7 @@ /* returns 1 if connection is via ipv4 */ int -packet_connection_is_ipv4(void) +packet_connection_is_ipv4() { struct sockaddr_storage to; socklen_t tolen = sizeof(to); @@ -190,7 +225,7 @@ /* Sets the connection into non-blocking mode. */ void -packet_set_nonblocking(void) +packet_set_nonblocking() { /* Set the socket into non-blocking mode. */ if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0) @@ -205,7 +240,7 @@ /* Returns the socket used for reading. */ int -packet_get_connection_in(void) +packet_get_connection_in() { return connection_in; } @@ -213,7 +248,7 @@ /* Returns the descriptor used for writing. */ int -packet_get_connection_out(void) +packet_get_connection_out() { return connection_out; } @@ -221,7 +256,7 @@ /* Closes the connection and clears and frees internal data structures. */ void -packet_close(void) +packet_close() { if (!initialized) return; @@ -237,26 +272,25 @@ buffer_free(&output); buffer_free(&outgoing_packet); buffer_free(&incoming_packet); - if (compression_buffer_ready) { + if (packet_compression) { buffer_free(&compression_buffer); buffer_compress_uninit(); } - cipher_cleanup(&send_context); - cipher_cleanup(&receive_context); } /* Sets remote side protocol flags. */ void -packet_set_protocol_flags(u_int protocol_flags) +packet_set_protocol_flags(unsigned int protocol_flags) { remote_protocol_flags = protocol_flags; + channel_set_options((protocol_flags & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) != 0); } /* Returns the remote protocol flags set earlier by the above function. */ -u_int -packet_get_protocol_flags(void) +unsigned int +packet_get_protocol_flags() { return remote_protocol_flags; } @@ -266,33 +300,57 @@ * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. */ -static void -packet_init_compression(void) +/*** XXXXX todo: kex means re-init */ +void +packet_start_compression(int level) { - if (compression_buffer_ready == 1) - return; - compression_buffer_ready = 1; + if (packet_compression) + fatal("Compression already enabled."); + packet_compression = 1; buffer_init(&compression_buffer); + buffer_compress_init(level); } +/* + * Encrypts the given number of bytes, copying from src to dest. bytes is + * known to be a multiple of 8. + */ + void -packet_start_compression(int level) +packet_encrypt(CipherContext * cc, void *dest, void *src, + unsigned int bytes) { - if (packet_compression && !compat20) - fatal("Compression already enabled."); - packet_compression = 1; - packet_init_compression(); - buffer_compress_init_send(level); - buffer_compress_init_recv(); + cipher_encrypt(cc, dest, src, bytes); } /* + * Decrypts the given number of bytes, copying from src to dest. bytes is + * known to be a multiple of 8. + */ + +void +packet_decrypt(CipherContext *context, void *dest, void *src, unsigned int bytes) +{ + /* + * Cryptographic attack detector for ssh - Modifications for packet.c + * (C)1998 CORE-SDI, Buenos Aires Argentina Ariel Futoransky(futo@core-sdi.com) + */ + if (!compat20 && + context->cipher->number != SSH_CIPHER_NONE && + detect_attack(src, bytes, NULL) == DEATTACK_DETECTED) + packet_disconnect("crc32 compensation attack: network attack detected"); + + cipher_decrypt(context, dest, src, bytes); +} + +/* * Causes any further packets to be encrypted using the given key. The same * key is used for both sending and reception. However, both directions are * encrypted independently of each other. */ + void -packet_set_encryption_key(const u_char *key, u_int keylen, +packet_set_encryption_key(const unsigned char *key, unsigned int keylen, int number) { Cipher *cipher = cipher_by_number(number); @@ -300,52 +358,85 @@ fatal("packet_set_encryption_key: unknown cipher number %d", number); if (keylen < 20) fatal("packet_set_encryption_key: keylen too small: %d", keylen); - cipher_init(&send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT); - cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT); + cipher_init(&receive_context, cipher, key, keylen, NULL, 0); + cipher_init(&send_context, cipher, key, keylen, NULL, 0); } -/* Start constructing a packet to send. */ +/* Starts constructing a packet to send. */ + void -packet_start(u_char type) +packet_start1(int type) { - u_char buf[9]; - int len; + char buf[9]; - DBG(debug("packet_start[%d]", type)); - len = compat20 ? 6 : 9; - memset(buf, 0, len - 1); - buf[len - 1] = type; buffer_clear(&outgoing_packet); - buffer_append(&outgoing_packet, buf, len); + memset(buf, 0, 8); + buf[8] = type; + buffer_append(&outgoing_packet, buf, 9); } -/* Append payload. */ void +packet_start2(int type) +{ + char buf[4+1+1]; + + buffer_clear(&outgoing_packet); + memset(buf, 0, sizeof buf); + /* buf[0..3] = payload_len; */ + /* buf[4] = pad_len; */ + buf[5] = type & 0xff; + buffer_append(&outgoing_packet, buf, sizeof buf); +} + +void +packet_start(int type) +{ + DBG(debug("packet_start[%d]",type)); + if (use_ssh2_packet_format) + packet_start2(type); + else + packet_start1(type); +} + +/* Appends a character to the packet data. */ + +void packet_put_char(int value) { char ch = value; buffer_append(&outgoing_packet, &ch, 1); } + +/* Appends an integer to the packet data. */ + void -packet_put_int(u_int value) +packet_put_int(unsigned int value) { buffer_put_int(&outgoing_packet, value); } + +/* Appends a string to packet data. */ + void -packet_put_string(const void *buf, u_int len) +packet_put_string(const char *buf, unsigned int len) { buffer_put_string(&outgoing_packet, buf, len); } void packet_put_cstring(const char *str) { - buffer_put_cstring(&outgoing_packet, str); + buffer_put_string(&outgoing_packet, str, strlen(str)); } + void -packet_put_raw(const void *buf, u_int len) +packet_put_raw(const char *buf, unsigned int len) { buffer_append(&outgoing_packet, buf, len); } + + +/* Appends an arbitrary precision integer to packet data. */ + void packet_put_bignum(BIGNUM * value) { @@ -362,12 +453,12 @@ * encrypts the packet before sending. */ -static void -packet_send1(void) +void +packet_send1() { - u_char buf[8], *cp; + char buf[8], *cp; int i, padding, len; - u_int checksum; + unsigned int checksum; u_int32_t rand = 0; /* @@ -383,14 +474,14 @@ buffer_compress(&outgoing_packet, &compression_buffer); buffer_clear(&outgoing_packet); buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), - buffer_len(&compression_buffer)); + buffer_len(&compression_buffer)); } /* Compute packet length without padding (add checksum, remove padding). */ len = buffer_len(&outgoing_packet) + 4 - 8; /* Insert padding. Initialized to zero in packet_start1() */ padding = 8 - len % 8; - if (!send_context.plaintext) { + if (cipher_type != SSH_CIPHER_NONE) { cp = buffer_ptr(&outgoing_packet); for (i = 0; i < padding; i++) { if (i % 4 == 0) @@ -402,7 +493,7 @@ buffer_consume(&outgoing_packet, 8 - padding); /* Add check bytes. */ - checksum = ssh_crc32(buffer_ptr(&outgoing_packet), + checksum = ssh_crc32((unsigned char *) buffer_ptr(&outgoing_packet), buffer_len(&outgoing_packet)); PUT_32BIT(buf, checksum); buffer_append(&outgoing_packet, buf, 4); @@ -415,9 +506,9 @@ /* Append to output. */ PUT_32BIT(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), - buffer_len(&outgoing_packet)); + buffer_append_space(&output, &cp, buffer_len(&outgoing_packet)); + packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet), + buffer_len(&outgoing_packet)); #ifdef PACKET_DEBUG fprintf(stderr, "encrypted: "); @@ -433,88 +524,33 @@ */ } -static void -set_newkeys(int mode) -{ - Enc *enc; - Mac *mac; - Comp *comp; - CipherContext *cc; - int encrypt; - - debug("newkeys: mode %d", mode); - - if (mode == MODE_OUT) { - cc = &send_context; - encrypt = CIPHER_ENCRYPT; - } else { - cc = &receive_context; - encrypt = CIPHER_DECRYPT; - } - if (newkeys[mode] != NULL) { - debug("newkeys: rekeying"); - cipher_cleanup(cc); - enc = &newkeys[mode]->enc; - mac = &newkeys[mode]->mac; - comp = &newkeys[mode]->comp; - memset(mac->key, 0, mac->key_len); - xfree(enc->name); - xfree(enc->iv); - xfree(enc->key); - xfree(mac->name); - xfree(mac->key); - xfree(comp->name); - xfree(newkeys[mode]); - } - newkeys[mode] = kex_get_newkeys(mode); - if (newkeys[mode] == NULL) - fatal("newkeys: no keys for mode %d", mode); - enc = &newkeys[mode]->enc; - mac = &newkeys[mode]->mac; - comp = &newkeys[mode]->comp; - if (mac->md != NULL) - 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); - memset(enc->iv, 0, enc->block_size); - memset(enc->key, 0, enc->key_len); - if (comp->type != 0 && comp->enabled == 0) { - 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) */ -static void -packet_send2(void) +void +packet_send2() { - static u_int32_t seqnr = 0; - u_char type, *cp, *macbuf = NULL; - u_char padlen, pad; - u_int packet_length = 0; - u_int i, len; + unsigned char *macbuf = NULL; + char *cp; + unsigned int packet_length = 0; + unsigned int i, padlen, len; u_int32_t rand = 0; + static unsigned int seqnr = 0; + int type; Enc *enc = NULL; Mac *mac = NULL; Comp *comp = NULL; int block_size; - if (newkeys[MODE_OUT] != NULL) { - enc = &newkeys[MODE_OUT]->enc; - mac = &newkeys[MODE_OUT]->mac; - comp = &newkeys[MODE_OUT]->comp; + if (kex != NULL) { + enc = &kex->enc[MODE_OUT]; + mac = &kex->mac[MODE_OUT]; + comp = &kex->comp[MODE_OUT]; } - block_size = enc ? enc->block_size : 8; + block_size = enc ? enc->cipher->block_size : 8; cp = buffer_ptr(&outgoing_packet); - type = cp[5]; + type = cp[5] & 0xff; #ifdef PACKET_DEBUG fprintf(stderr, "plain: "); @@ -545,23 +581,14 @@ padlen = block_size - (len % block_size); if (padlen < 4) padlen += block_size; - if (extra_pad) { - /* will wrap if extra_pad+padlen > 255 */ - extra_pad = roundup(extra_pad, block_size); - pad = extra_pad - ((len + padlen) % extra_pad); - debug("packet_send2: adding %d (len %d padlen %d extra_pad %d)", - pad, len, padlen, extra_pad); - padlen += pad; - extra_pad = 0; - } - cp = buffer_append_space(&outgoing_packet, padlen); - if (enc && !send_context.plaintext) { + buffer_append_space(&outgoing_packet, &cp, padlen); + if (enc && enc->cipher->number != SSH_CIPHER_NONE) { /* random padding */ for (i = 0; i < padlen; i++) { if (i % 4 == 0) rand = arc4random(); cp[i] = rand & 0xff; - rand >>= 8; + rand <<= 8; } } else { /* clear padding */ @@ -571,19 +598,21 @@ packet_length = buffer_len(&outgoing_packet) - 4; cp = buffer_ptr(&outgoing_packet); PUT_32BIT(cp, packet_length); - cp[4] = padlen; + cp[4] = padlen & 0xff; DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); /* compute MAC over seqnr and packet(length fields, payload, padding) */ if (mac && mac->enabled) { - macbuf = mac_compute(mac, seqnr, - buffer_ptr(&outgoing_packet), - buffer_len(&outgoing_packet)); + macbuf = hmac( mac->md, seqnr, + (unsigned char *) buffer_ptr(&outgoing_packet), + buffer_len(&outgoing_packet), + mac->key, mac->key_len + ); DBG(debug("done calc MAC out #%d", seqnr)); } /* encrypt packet and append to output buffer. */ - cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); - cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet), + buffer_append_space(&output, &cp, buffer_len(&outgoing_packet)); + packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet), buffer_len(&outgoing_packet)); /* append unencrypted MAC */ if (mac && mac->enabled) @@ -597,14 +626,28 @@ log("outgoing seqnr wraps around"); buffer_clear(&outgoing_packet); - if (type == SSH2_MSG_NEWKEYS) - set_newkeys(MODE_OUT); + if (type == SSH2_MSG_NEWKEYS) { + if (kex==NULL || mac==NULL || enc==NULL || comp==NULL) + fatal("packet_send2: no KEX"); + if (mac->md != NULL) + mac->enabled = 1; + DBG(debug("cipher_init send_context")); + cipher_init(&send_context, enc->cipher, + enc->key, enc->cipher->key_len, + enc->iv, enc->cipher->block_size); + clear_enc_keys(enc, kex->we_need); + if (comp->type != 0 && comp->enabled == 0) { + comp->enabled = 1; + if (! packet_compression) + packet_start_compression(6); + } + } } void -packet_send(void) +packet_send() { - if (compat20) + if (use_ssh2_packet_format) packet_send2(); else packet_send1(); @@ -618,46 +661,38 @@ */ int -packet_read_seqnr(u_int32_t *seqnr_p) +packet_read(int *payload_len_ptr) { int type, len; - fd_set *setp; + fd_set set; char buf[8192]; DBG(debug("packet_read()")); - setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) * - sizeof(fd_mask)); - /* Since we are blocking, ensure that all written packets have been sent. */ packet_write_wait(); /* Stay in the loop until we have received a complete packet. */ for (;;) { /* Try to read a packet from the buffer. */ - type = packet_read_poll_seqnr(seqnr_p); - if (!compat20 && ( + type = packet_read_poll(payload_len_ptr); + if (!use_ssh2_packet_format && ( type == SSH_SMSG_SUCCESS || type == SSH_SMSG_FAILURE || type == SSH_CMSG_EOF || type == SSH_CMSG_EXIT_CONFIRMATION)) - packet_check_eom(); + packet_integrity_check(*payload_len_ptr, 0, type); /* If we got a packet, return it. */ - if (type != SSH_MSG_NONE) { - xfree(setp); + if (type != SSH_MSG_NONE) return type; - } /* * Otherwise, wait for some data to arrive, add it to the * buffer, and try again. */ - memset(setp, 0, howmany(connection_in + 1, NFDBITS) * - sizeof(fd_mask)); - FD_SET(connection_in, setp); + FD_ZERO(&set); + FD_SET(connection_in, &set); /* Wait for some data to arrive. */ - while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 && - (errno == EAGAIN || errno == EINTR)) - ; + select(connection_in + 1, &set, NULL, NULL, NULL); /* Read data from the socket. */ len = read(connection_in, buf, sizeof(buf)); @@ -673,23 +708,17 @@ /* NOTREACHED */ } -int -packet_read(void) -{ - return packet_read_seqnr(NULL); -} - /* * 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. */ void -packet_read_expect(int expected_type) +packet_read_expect(int *payload_len_ptr, int expected_type) { int type; - type = packet_read(); + type = packet_read(payload_len_ptr); if (type != expected_type) packet_disconnect("Protocol error: expected packet type %d, got %d", expected_type, type); @@ -702,21 +731,28 @@ * SSH_MSG_DISCONNECT is handled specially here. Also, * SSH_MSG_IGNORE messages are skipped by this function and are never returned * to higher levels. + * + * The returned payload_len does include space consumed by: + * Packet length + * Padding + * Packet type + * Check bytes */ -static int -packet_read_poll1(void) +int +packet_read_poll1(int *payload_len_ptr) { - u_int len, padded_len; - u_char *cp, type; - u_int checksum, stored_checksum; + unsigned int len, padded_len; + unsigned char *ucp; + char buf[8], *cp; + unsigned int checksum, stored_checksum; /* Check if input size is less than minimum packet size. */ if (buffer_len(&input) < 4 + 8) return SSH_MSG_NONE; /* Get length of incoming packet. */ - cp = buffer_ptr(&input); - len = GET_32BIT(cp); + ucp = (unsigned char *) buffer_ptr(&input); + len = GET_32BIT(ucp); if (len < 1 + 2 + 2 || len > 256 * 1024) packet_disconnect("Bad packet length %d.", len); padded_len = (len + 8) & ~7; @@ -730,20 +766,10 @@ /* Consume packet length. */ buffer_consume(&input, 4); - /* - * Cryptographic attack detector for ssh - * (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"); - - /* Decrypt data to incoming_packet. */ + /* Copy data to incoming_packet. */ buffer_clear(&incoming_packet); - cp = buffer_append_space(&incoming_packet, padded_len); - cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len); - + buffer_append_space(&incoming_packet, &cp, padded_len); + packet_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len); buffer_consume(&input, padded_len); #ifdef PACKET_DEBUG @@ -752,23 +778,25 @@ #endif /* Compute packet checksum. */ - checksum = ssh_crc32(buffer_ptr(&incoming_packet), + checksum = ssh_crc32((unsigned char *) buffer_ptr(&incoming_packet), buffer_len(&incoming_packet) - 4); /* Skip padding. */ buffer_consume(&incoming_packet, 8 - len % 8); /* Test check bytes. */ + if (len != buffer_len(&incoming_packet)) - packet_disconnect("packet_read_poll1: len %d != buffer_len %d.", + packet_disconnect("packet_read_poll: len %d != buffer_len %d.", len, buffer_len(&incoming_packet)); - cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4; - stored_checksum = GET_32BIT(cp); + ucp = (unsigned char *) buffer_ptr(&incoming_packet) + len - 4; + stored_checksum = GET_32BIT(ucp); if (checksum != stored_checksum) packet_disconnect("Corrupted check bytes on input."); buffer_consume_end(&incoming_packet, 4); + /* If using packet compression, decompress the packet. */ if (packet_compression) { buffer_clear(&compression_buffer); buffer_uncompress(&incoming_packet, &compression_buffer); @@ -776,29 +804,38 @@ buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), buffer_len(&compression_buffer)); } - type = buffer_get_char(&incoming_packet); - return type; + /* Get packet type. */ + buffer_get(&incoming_packet, &buf[0], 1); + + /* Return length of payload (without type field). */ + *payload_len_ptr = buffer_len(&incoming_packet); + + /* Return type. */ + return (unsigned char) buf[0]; } -static int -packet_read_poll2(u_int32_t *seqnr_p) +int +packet_read_poll2(int *payload_len_ptr) { - static u_int32_t seqnr = 0; - static u_int packet_length = 0; - u_int padlen, need; - u_char *macbuf, *cp, type; + unsigned int padlen, need; + unsigned char buf[8], *macbuf; + unsigned char *ucp; + char *cp; + static unsigned int packet_length = 0; + static unsigned int seqnr = 0; + int type; int maclen, block_size; Enc *enc = NULL; Mac *mac = NULL; Comp *comp = NULL; - if (newkeys[MODE_IN] != NULL) { - enc = &newkeys[MODE_IN]->enc; - mac = &newkeys[MODE_IN]->mac; - comp = &newkeys[MODE_IN]->comp; + if (kex != NULL) { + enc = &kex->enc[MODE_IN]; + mac = &kex->mac[MODE_IN]; + comp = &kex->comp[MODE_IN]; } maclen = mac && mac->enabled ? mac->mac_len : 0; - block_size = enc ? enc->block_size : 8; + block_size = enc ? enc->cipher->block_size : 8; if (packet_length == 0) { /* @@ -808,11 +845,11 @@ if (buffer_len(&input) < block_size) return SSH_MSG_NONE; buffer_clear(&incoming_packet); - cp = buffer_append_space(&incoming_packet, block_size); - cipher_crypt(&receive_context, cp, buffer_ptr(&input), + buffer_append_space(&incoming_packet, &cp, block_size); + packet_decrypt(&receive_context, cp, buffer_ptr(&input), block_size); - cp = buffer_ptr(&incoming_packet); - packet_length = GET_32BIT(cp); + ucp = (unsigned char *) buffer_ptr(&incoming_packet); + packet_length = GET_32BIT(ucp); if (packet_length < 1 + 4 || packet_length > 256 * 1024) { buffer_dump(&incoming_packet); packet_disconnect("Bad packet length %d.", packet_length); @@ -837,30 +874,30 @@ fprintf(stderr, "read_poll enc/full: "); buffer_dump(&input); #endif - cp = buffer_append_space(&incoming_packet, need); - cipher_crypt(&receive_context, cp, buffer_ptr(&input), need); + buffer_append_space(&incoming_packet, &cp, need); + packet_decrypt(&receive_context, cp, buffer_ptr(&input), need); buffer_consume(&input, need); /* * compute MAC over seqnr and packet, * increment sequence number for incoming packet */ if (mac && mac->enabled) { - macbuf = mac_compute(mac, seqnr, - buffer_ptr(&incoming_packet), - buffer_len(&incoming_packet)); + macbuf = hmac( mac->md, seqnr, + (unsigned char *) buffer_ptr(&incoming_packet), + buffer_len(&incoming_packet), + mac->key, mac->key_len + ); if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0) packet_disconnect("Corrupted MAC on input."); DBG(debug("MAC #%d ok", seqnr)); buffer_consume(&input, mac->mac_len); } - if (seqnr_p != NULL) - *seqnr_p = seqnr; if (++seqnr == 0) log("incoming seqnr wraps around"); /* get padlen */ - cp = buffer_ptr(&incoming_packet); - padlen = cp[4]; + cp = buffer_ptr(&incoming_packet) + 4; + padlen = *cp & 0xff; DBG(debug("input: padlen %d", padlen)); if (padlen < 4) packet_disconnect("Corrupted padlen %d on input.", padlen); @@ -882,31 +919,53 @@ * get packet type, implies consume. * return length of payload (without type field) */ - type = buffer_get_char(&incoming_packet); - if (type == SSH2_MSG_NEWKEYS) - set_newkeys(MODE_IN); + buffer_get(&incoming_packet, (char *)&buf[0], 1); + *payload_len_ptr = buffer_len(&incoming_packet); + + /* reset for next packet */ + packet_length = 0; + + /* extract packet type */ + type = (unsigned char)buf[0]; + + if (type == SSH2_MSG_NEWKEYS) { + if (kex==NULL || mac==NULL || enc==NULL || comp==NULL) + fatal("packet_read_poll2: no KEX"); + if (mac->md != NULL) + mac->enabled = 1; + DBG(debug("cipher_init receive_context")); + cipher_init(&receive_context, enc->cipher, + enc->key, enc->cipher->key_len, + enc->iv, enc->cipher->block_size); + clear_enc_keys(enc, kex->we_need); + if (comp->type != 0 && comp->enabled == 0) { + comp->enabled = 1; + if (! packet_compression) + packet_start_compression(6); + } + } + #ifdef PACKET_DEBUG - fprintf(stderr, "read/plain[%d]:\r\n", type); + fprintf(stderr, "read/plain[%d]:\r\n",type); buffer_dump(&incoming_packet); #endif - /* reset for next packet */ - packet_length = 0; - return type; + return (unsigned char)type; } int -packet_read_poll_seqnr(u_int32_t *seqnr_p) +packet_read_poll(int *payload_len_ptr) { - int reason, seqnr; - u_char type; char *msg; - for (;;) { - if (compat20) { - type = packet_read_poll2(seqnr_p); - if (type) + int type = use_ssh2_packet_format ? + packet_read_poll2(payload_len_ptr): + packet_read_poll1(payload_len_ptr); + + if(compat20) { + int reason; + if (type != 0) DBG(debug("received packet type %d", type)); - switch (type) { + switch(type) { case SSH2_MSG_IGNORE: break; case SSH2_MSG_DEBUG: @@ -920,22 +979,16 @@ case SSH2_MSG_DISCONNECT: reason = packet_get_int(); msg = packet_get_string(NULL); - log("Received disconnect from %s: %d: %.400s", get_remote_ipaddr(), - reason, msg); + log("Received disconnect: %d: %.900s", reason, msg); xfree(msg); fatal_cleanup(); break; - case SSH2_MSG_UNIMPLEMENTED: - seqnr = packet_get_int(); - debug("Received SSH2_MSG_UNIMPLEMENTED for %d", seqnr); - break; default: return type; break; - } + } } else { - type = packet_read_poll1(); - switch (type) { + switch(type) { case SSH_MSG_IGNORE: break; case SSH_MSG_DEBUG: @@ -945,52 +998,45 @@ break; case SSH_MSG_DISCONNECT: msg = packet_get_string(NULL); - log("Received disconnect from %s: %.400s", get_remote_ipaddr(), - msg); + log("Received disconnect: %.900s", msg); fatal_cleanup(); xfree(msg); break; default: - if (type) + if (type != 0) DBG(debug("received packet type %d", type)); return type; break; - } + } } } } -int -packet_read_poll(void) -{ - return packet_read_poll_seqnr(NULL); -} - /* * Buffers the given amount of input characters. This is intended to be used * together with packet_read_poll. */ void -packet_process_incoming(const char *buf, u_int len) +packet_process_incoming(const char *buf, unsigned int len) { buffer_append(&input, buf, len); } /* Returns a character from the packet. */ -u_int -packet_get_char(void) +unsigned int +packet_get_char() { char ch; buffer_get(&incoming_packet, &ch, 1); - return (u_char) ch; + return (unsigned char) ch; } /* Returns an integer from the packet data. */ -u_int -packet_get_int(void) +unsigned int +packet_get_int() { return buffer_get_int(&incoming_packet); } @@ -1001,18 +1047,18 @@ */ void -packet_get_bignum(BIGNUM * value) +packet_get_bignum(BIGNUM * value, int *length_ptr) { - buffer_get_bignum(&incoming_packet, value); + *length_ptr = buffer_get_bignum(&incoming_packet, value); } void -packet_get_bignum2(BIGNUM * value) +packet_get_bignum2(BIGNUM * value, int *length_ptr) { - buffer_get_bignum2(&incoming_packet, value); + *length_ptr = buffer_get_bignum2(&incoming_packet, value); } -void * +char * packet_get_raw(int *length_ptr) { int bytes = buffer_len(&incoming_packet); @@ -1034,8 +1080,8 @@ * integer into which the length of the string is stored. */ -void * -packet_get_string(u_int *length_ptr) +char * +packet_get_string(unsigned int *length_ptr) { return buffer_get_string(&incoming_packet, length_ptr); } @@ -1108,13 +1154,13 @@ packet_put_cstring(""); } else { packet_start(SSH_MSG_DISCONNECT); - packet_put_cstring(buf); + packet_put_string(buf, strlen(buf)); } packet_send(); packet_write_wait(); /* Stop listening for connections. */ - channel_close_all(); + channel_stop_listening(); /* Close the connection. */ packet_close(); @@ -1127,7 +1173,7 @@ /* Checks if there is any buffered output, and tries to write some of the output. */ void -packet_write_poll(void) +packet_write_poll() { int len = buffer_len(&output); if (len > 0) { @@ -1148,29 +1194,22 @@ */ void -packet_write_wait(void) +packet_write_wait() { - fd_set *setp; - - setp = (fd_set *)xmalloc(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)) - ; + fd_set set; + FD_ZERO(&set); + FD_SET(connection_out, &set); + select(connection_out + 1, NULL, &set, NULL, NULL); packet_write_poll(); } - xfree(setp); } /* Returns true if there is buffered data to write to the connection. */ int -packet_have_data_to_write(void) +packet_have_data_to_write() { return buffer_len(&output) != 0; } @@ -1178,7 +1217,7 @@ /* Returns true if there is not too much data to write to the connection. */ int -packet_not_very_much_data_to_write(void) +packet_not_very_much_data_to_write() { if (interactive_mode) return buffer_len(&output) < 16384; @@ -1189,43 +1228,46 @@ /* Informs that the current session is interactive. Sets IP flags for that. */ void -packet_set_interactive(int interactive) +packet_set_interactive(int interactive, int keepalives) { - static int called = 0; - int lowdelay = IPTOS_LOWDELAY; - int throughput = IPTOS_THROUGHPUT; + int on = 1; - if (called) - return; - called = 1; - /* Record that we are in interactive mode. */ interactive_mode = interactive; /* Only set socket options if using a socket. */ if (!packet_connection_is_on_socket()) return; + if (keepalives) { + /* Set keepalives if requested. */ + if (setsockopt(connection_in, SOL_SOCKET, SO_KEEPALIVE, (void *) &on, + sizeof(on)) < 0) + error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); + } /* - * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only + * IPTOS_LOWDELAY, TCP_NODELAY and IPTOS_THROUGHPUT are IPv4 only */ + if (!packet_connection_is_ipv4()) + return; if (interactive) { /* * Set IP options for an interactive connection. Use * IPTOS_LOWDELAY and TCP_NODELAY. */ - if (packet_connection_is_ipv4()) { - if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, - &lowdelay, sizeof(lowdelay)) < 0) - error("setsockopt IPTOS_LOWDELAY: %.100s", - strerror(errno)); - } - set_nodelay(connection_in); - } else if (packet_connection_is_ipv4()) { + int lowdelay = IPTOS_LOWDELAY; + if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &lowdelay, + sizeof(lowdelay)) < 0) + error("setsockopt IPTOS_LOWDELAY: %.100s", strerror(errno)); + if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on, + sizeof(on)) < 0) + error("setsockopt TCP_NODELAY: %.100s", strerror(errno)); + } else { /* * Set IP options for a non-interactive connection. Use * IPTOS_THROUGHPUT. */ - if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &throughput, + int throughput = IPTOS_THROUGHPUT; + if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput, sizeof(throughput)) < 0) error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno)); } @@ -1234,7 +1276,7 @@ /* Returns true if the current connection is interactive. */ int -packet_is_interactive(void) +packet_is_interactive() { return interactive_mode; } @@ -1252,42 +1294,7 @@ log("packet_set_maxsize: bad size %d", s); return -1; } - called = 1; - debug("packet_set_maxsize: setting to %d", s); + log("packet_set_maxsize: setting to %d", s); max_packet_size = s; return s; -} - -/* roundup current message to pad bytes */ -void -packet_add_padding(u_char pad) -{ - extra_pad = pad; -} - -/* - * 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. - */ -void -packet_send_ignore(int nbytes) -{ - u_int32_t rand = 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; - } }