X-Git-Url: http://andersk.mit.edu/gitweb/gssapi-openssh.git/blobdiff_plain/0b582e461dc11f0887b249b6b60bbbf52687850d..436bf0dada8139f94ab4537fcefd421b52a86564:/openssh/packet.c diff --git a/openssh/packet.c b/openssh/packet.c index 49c6e7a..36656ba 100644 --- a/openssh/packet.c +++ b/openssh/packet.c @@ -1,3 +1,4 @@ +/* $OpenBSD: packet.c,v 1.148 2007/06/07 19:37:34 pvalchev Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland @@ -37,28 +38,45 @@ */ #include "includes.h" -RCSID("$OpenBSD: packet.c,v 1.72 2001/11/10 13:37:20 markus 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" #include "canohost.h" +#include "misc.h" +#include "ssh.h" #ifdef PACKET_DEBUG #define DBG(x) x @@ -85,10 +103,10 @@ static CipherContext receive_context; static CipherContext send_context; /* Buffer for raw input data from the socket. */ -static Buffer input; +Buffer input; /* Buffer for raw output data going to the socket. */ -static Buffer output; +Buffer output; /* Buffer for the partial outgoing packet being constructed. */ static Buffer outgoing_packet; @@ -104,7 +122,7 @@ static int compression_buffer_ready = 0; static int packet_compression = 0; /* default maximum packet size */ -int max_packet_size = 32768; +u_int max_packet_size = 32768; /* Flag indicating whether this module has been initialized. */ static int initialized = 0; @@ -112,12 +130,37 @@ 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; + /* 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; +} p_read, p_send; + +static u_int64_t max_blocks_in, max_blocks_out; +static u_int32_t rekey_limit; + +/* Session key for protocol v1 */ +static u_char ssh1_key[SSH_SESSION_KEY_LENGTH]; +static u_int ssh1_keylen; /* roundup current message to extra_pad bytes */ static u_char extra_pad = 0; +struct packet { + TAILQ_ENTRY(packet) next; + u_char type; + Buffer payload; +}; +TAILQ_HEAD(, packet) outgoing; + /* * Sets the descriptors used for communication. Disables encryption until * packet_set_encryption_key is called. @@ -126,12 +169,15 @@ void packet_set_connection(int fd_in, int fd_out) { Cipher *none = cipher_by_name("none"); + if (none == NULL) fatal("packet_set_connection: cannot load cipher 'none'"); connection_in = fd_in; connection_out = fd_out; - cipher_init(&send_context, none, (u_char *) "", 0, NULL, 0); - cipher_init(&receive_context, none, (u_char *) "", 0, NULL, 0); + cipher_init(&send_context, none, (const u_char *)"", + 0, NULL, 0, CIPHER_ENCRYPT); + cipher_init(&receive_context, none, (const u_char *)"", + 0, NULL, 0, CIPHER_DECRYPT); newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL; if (!initialized) { initialized = 1; @@ -139,15 +185,14 @@ packet_set_connection(int fd_in, int fd_out) buffer_init(&output); buffer_init(&outgoing_packet); buffer_init(&incoming_packet); + TAILQ_INIT(&outgoing); } - /* Kludge: arrange the close function to be called from fatal(). */ - fatal_add_cleanup((void (*) (void *)) packet_close, NULL); } /* Returns 1 if remote host is connected via socket, 0 if not. */ int -packet_connection_is_on_socket() +packet_connection_is_on_socket(void) { struct sockaddr_storage from, to; socklen_t fromlen, tolen; @@ -170,10 +215,109 @@ packet_connection_is_on_socket() return 1; } +/* + * Exports an IV from the CipherContext required to export the key + * state back from the unprivileged child to the privileged parent + * process. + */ + +void +packet_get_keyiv(int mode, u_char *iv, u_int len) +{ + CipherContext *cc; + + if (mode == MODE_OUT) + cc = &send_context; + else + cc = &receive_context; + + cipher_get_keyiv(cc, iv, len); +} + +int +packet_get_keycontext(int mode, u_char *dat) +{ + CipherContext *cc; + + if (mode == MODE_OUT) + cc = &send_context; + else + cc = &receive_context; + + return (cipher_get_keycontext(cc, dat)); +} + +void +packet_set_keycontext(int mode, u_char *dat) +{ + CipherContext *cc; + + if (mode == MODE_OUT) + cc = &send_context; + else + cc = &receive_context; + + cipher_set_keycontext(cc, dat); +} + +int +packet_get_keyiv_len(int mode) +{ + CipherContext *cc; + + if (mode == MODE_OUT) + cc = &send_context; + else + cc = &receive_context; + + return (cipher_get_keyiv_len(cc)); +} + +void +packet_set_iv(int mode, u_char *dat) +{ + CipherContext *cc; + + if (mode == MODE_OUT) + cc = &send_context; + else + cc = &receive_context; + + cipher_set_keyiv(cc, dat); +} + +int +packet_get_ssh1_cipher(void) +{ + return (cipher_get_number(receive_context.cipher)); +} + +void +packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets) +{ + struct packet_state *state; + + state = (mode == MODE_IN) ? &p_read : &p_send; + *seqnr = state->seqnr; + *blocks = state->blocks; + *packets = state->packets; +} + +void +packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets) +{ + struct packet_state *state; + + state = (mode == MODE_IN) ? &p_read : &p_send; + state->seqnr = seqnr; + state->blocks = blocks; + state->packets = packets; +} + /* returns 1 if connection is via ipv4 */ int -packet_connection_is_ipv4() +packet_connection_is_ipv4(void) { struct sockaddr_storage to; socklen_t tolen = sizeof(to); @@ -181,30 +325,32 @@ packet_connection_is_ipv4() memset(&to, 0, sizeof(to)); if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0) return 0; - if (to.ss_family != AF_INET) - return 0; - return 1; + if (to.ss_family == AF_INET) + return 1; +#ifdef IPV4_IN_IPV6 + if (to.ss_family == AF_INET6 && + IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr)) + return 1; +#endif + return 0; } /* Sets the connection into non-blocking mode. */ void -packet_set_nonblocking() +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. */ int -packet_get_connection_in() +packet_get_connection_in(void) { return connection_in; } @@ -212,7 +358,7 @@ packet_get_connection_in() /* Returns the descriptor used for writing. */ int -packet_get_connection_out() +packet_get_connection_out(void) { return connection_out; } @@ -220,7 +366,7 @@ packet_get_connection_out() /* Closes the connection and clears and frees internal data structures. */ void -packet_close() +packet_close(void) { if (!initialized) return; @@ -240,6 +386,8 @@ packet_close() buffer_free(&compression_buffer); buffer_compress_uninit(); } + cipher_cleanup(&send_context); + cipher_cleanup(&receive_context); } /* Sets remote side protocol flags. */ @@ -253,7 +401,7 @@ packet_set_protocol_flags(u_int protocol_flags) /* Returns the remote protocol flags set earlier by the above function. */ u_int -packet_get_protocol_flags() +packet_get_protocol_flags(void) { return remote_protocol_flags; } @@ -288,17 +436,32 @@ packet_start_compression(int level) * 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, int number) { Cipher *cipher = cipher_by_number(number); + if (cipher == NULL) 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(&receive_context, cipher, key, keylen, NULL, 0); - cipher_init(&send_context, cipher, key, keylen, NULL, 0); + if (keylen > SSH_SESSION_KEY_LENGTH) + fatal("packet_set_encryption_key: keylen too big: %d", keylen); + memcpy(ssh1_key, key, keylen); + ssh1_keylen = keylen; + cipher_init(&send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT); + cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT); +} + +u_int +packet_get_encryption_key(u_char *key) +{ + if (key == NULL) + return (ssh1_keylen); + memcpy(key, ssh1_key, ssh1_keylen); + return (ssh1_keylen); } /* Start constructing a packet to send. */ @@ -321,33 +484,40 @@ void packet_put_char(int value) { char ch = 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 char *buf, u_int len) +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 char *buf, u_int len) +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) { @@ -362,10 +532,10 @@ packet_put_bignum2(BIGNUM * value) static void packet_send1(void) { - char buf[8], *cp; + 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 @@ -380,28 +550,28 @@ packet_send1(void) 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.cipher->number != SSH_CIPHER_NONE) { + if (!send_context.plaintext) { 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); /* Add check bytes. */ - checksum = ssh_crc32((u_char *) buffer_ptr(&outgoing_packet), + 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 @@ -410,11 +580,11 @@ packet_send1(void) #endif /* Append to output. */ - PUT_32BIT(buf, len); + put_u32(buf, len); buffer_append(&output, buf, 4); - buffer_append_space(&output, &cp, buffer_len(&outgoing_packet)); - cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet), - buffer_len(&outgoing_packet)); + cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); + cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet), + buffer_len(&outgoing_packet)); #ifdef PACKET_DEBUG fprintf(stderr, "encrypted: "); @@ -424,31 +594,42 @@ packet_send1(void) 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. */ } -static void +void set_newkeys(int mode) { Enc *enc; Mac *mac; Comp *comp; CipherContext *cc; + u_int64_t *max_blocks; + int crypt_type; - debug("newkeys: mode %d", mode); + debug2("set_newkeys: mode %d", mode); - cc = (mode == MODE_OUT) ? &send_context : &receive_context; + if (mode == MODE_OUT) { + cc = &send_context; + crypt_type = CIPHER_ENCRYPT; + p_send.packets = p_send.blocks = 0; + max_blocks = &max_blocks_out; + } else { + cc = &receive_context; + crypt_type = CIPHER_DECRYPT; + p_read.packets = p_read.blocks = 0; + max_blocks = &max_blocks_in; + } if (newkeys[mode] != NULL) { - debug("newkeys: rekeying"); - /* todo: free old keys, reset compression/cipher-ctxt; */ - memset(cc, 0, sizeof(*cc)); + debug("set_newkeys: rekeying"); + cipher_cleanup(cc); 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); @@ -463,14 +644,18 @@ 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->cipher->key_len, - enc->iv, enc->cipher->block_size); - memset(enc->iv, 0, enc->cipher->block_size); - memset(enc->key, 0, enc->cipher->key_len); - if (comp->type != 0 && comp->enabled == 0) { + cipher_init(cc, enc->cipher, enc->key, enc->key_len, + 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); + 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); @@ -478,21 +663,61 @@ set_newkeys(int mode) buffer_compress_init_recv(); comp->enabled = 1; } + /* + * The 2^(blocksize*2) limit is too expensive for 3DES, + * blowfish, etc, so enforce a 1GB limit for small blocksizes. + */ + 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 (rekey_limit) + *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) */ static void -packet_send2(void) +packet_send2_wrapped(void) { - static u_int32_t seqnr = 0; - u_char type, *ucp, *macbuf = NULL; + u_char type, *cp, *macbuf = NULL; u_char padlen, pad; - char *cp; 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; @@ -503,10 +728,10 @@ packet_send2(void) mac = &newkeys[MODE_OUT]->mac; comp = &newkeys[MODE_OUT]->comp; } - block_size = enc ? enc->cipher->block_size : 8; + block_size = enc ? enc->block_size : 8; - ucp = (u_char *) buffer_ptr(&outgoing_packet); - type = ucp[5]; + cp = buffer_ptr(&outgoing_packet); + type = cp[5]; #ifdef PACKET_DEBUG fprintf(stderr, "plain: "); @@ -541,19 +766,19 @@ packet_send2(void) /* 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)", + debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)", pad, len, padlen, extra_pad); padlen += pad; extra_pad = 0; } - buffer_append_space(&outgoing_packet, &cp, padlen); - if (enc && enc->cipher->number != SSH_CIPHER_NONE) { + cp = buffer_append_space(&outgoing_packet, padlen); + if (enc && !send_context.plaintext) { /* 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 */ @@ -561,40 +786,92 @@ packet_send2(void) } /* packet_length includes payload, padding and padding length field */ packet_length = buffer_len(&outgoing_packet) - 4; - ucp = (u_char *)buffer_ptr(&outgoing_packet); - PUT_32BIT(ucp, packet_length); - ucp[4] = padlen; + cp = buffer_ptr(&outgoing_packet); + put_u32(cp, packet_length); + cp[4] = padlen; 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, - (u_char *) buffer_ptr(&outgoing_packet), + macbuf = mac_compute(mac, p_send.seqnr, + buffer_ptr(&outgoing_packet), buffer_len(&outgoing_packet)); - DBG(debug("done calc MAC out #%d", seqnr)); + DBG(debug("done calc MAC out #%d", p_send.seqnr)); } /* encrypt packet and append to output buffer. */ - buffer_append_space(&output, &cp, buffer_len(&outgoing_packet)); - cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet), + cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); + cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet), 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); #endif /* increment sequence number for outgoing packets */ - if (++seqnr == 0) - log("outgoing seqnr wraps around"); + if (++p_send.seqnr == 0) + logit("outgoing seqnr wraps around"); + if (++p_send.packets == 0) + if (!(datafellows & SSH_BUG_NOREKEY)) + fatal("XXX too many packets with same key"); + p_send.blocks += (packet_length + 4) / block_size; 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 +packet_send2(void) +{ + static int rekeying = 0; + struct packet *p; + u_char type, *cp; + + cp = buffer_ptr(&outgoing_packet); + type = cp[5]; + + /* during rekeying we can only send key exchange messages */ + if (rekeying) { + if (!((type >= SSH2_MSG_TRANSPORT_MIN) && + (type <= SSH2_MSG_TRANSPORT_MAX))) { + debug("enqueue packet: %u", type); + p = xmalloc(sizeof(*p)); + p->type = type; + memcpy(&p->payload, &outgoing_packet, sizeof(Buffer)); + buffer_init(&outgoing_packet); + TAILQ_INSERT_TAIL(&outgoing, p, next); + return; + } + } + + /* rekeying starts with sending KEXINIT */ + if (type == SSH2_MSG_KEXINIT) + rekeying = 1; + + packet_send2_wrapped(); + + /* after a NEWKEYS message we can send the complete queue */ + if (type == SSH2_MSG_NEWKEYS) { + rekeying = 0; + while ((p = TAILQ_FIRST(&outgoing))) { + type = p->type; + debug("dequeue packet: %u", type); + buffer_free(&outgoing_packet); + memcpy(&outgoing_packet, &p->payload, + sizeof(Buffer)); + TAILQ_REMOVE(&outgoing, p, next); + xfree(p); + packet_send2_wrapped(); + } + } } void -packet_send() +packet_send(void) { if (compat20) packet_send2(); @@ -610,14 +887,14 @@ packet_send() */ int -packet_read(int *payload_len_ptr) +packet_read_seqnr(u_int32_t *seqnr_p) { int type, len; fd_set *setp; char buf[8192]; 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. */ @@ -626,13 +903,13 @@ packet_read(int *payload_len_ptr) /* Stay in the loop until we have received a complete packet. */ for (;;) { /* Try to read a packet from the buffer. */ - type = packet_read_poll(payload_len_ptr); + type = packet_read_poll_seqnr(seqnr_p); if (!compat20 && ( type == SSH_SMSG_SUCCESS || type == SSH_SMSG_FAILURE || type == SSH_CMSG_EOF || type == SSH_CMSG_EXIT_CONFIRMATION)) - packet_integrity_check(*payload_len_ptr, 0, type); + packet_check_eom(); /* If we got a packet, return it. */ if (type != SSH_MSG_NONE) { xfree(setp); @@ -654,8 +931,8 @@ packet_read(int *payload_len_ptr) /* Read data from the socket. */ len = read(connection_in, buf, sizeof(buf)); if (len == 0) { - log("Connection closed by %.200s", get_remote_ipaddr()); - fatal_cleanup(); + logit("Connection closed by %.200s", get_remote_ipaddr()); + cleanup_exit(255); } if (len < 0) fatal("Read from socket failed: %.100s", strerror(errno)); @@ -665,17 +942,23 @@ packet_read(int *payload_len_ptr) /* 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 *payload_len_ptr, int expected_type) +packet_read_expect(int expected_type) { int type; - type = packet_read(payload_len_ptr); + type = packet_read(); if (type != expected_type) packet_disconnect("Protocol error: expected packet type %d, got %d", expected_type, type); @@ -688,30 +971,23 @@ packet_read_expect(int *payload_len_ptr, int expected_type) * 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(int *payload_len_ptr) +packet_read_poll1(void) { u_int len, padded_len; - u_char *ucp, type; - char *cp; + u_char *cp, type; u_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. */ - ucp = (u_char *) buffer_ptr(&input); - len = GET_32BIT(ucp); + cp = buffer_ptr(&input); + len = get_u32(cp); if (len < 1 + 2 + 2 || len > 256 * 1024) - packet_disconnect("Bad packet length %d.", len); + packet_disconnect("Bad packet length %u.", len); padded_len = (len + 8) & ~7; /* Check if the packet has been entirely received. */ @@ -728,14 +1004,21 @@ packet_read_poll1(int *payload_len_ptr) * (C)1998 CORE-SDI, Buenos Aires Argentina * Ariel Futoransky(futo@core-sdi.com) */ - if (receive_context.cipher->number != SSH_CIPHER_NONE && - 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); - buffer_append_space(&incoming_packet, &cp, padded_len); - cipher_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len); + cp = buffer_append_space(&incoming_packet, padded_len); + cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len); buffer_consume(&input, padded_len); @@ -745,7 +1028,7 @@ packet_read_poll1(int *payload_len_ptr) #endif /* Compute packet checksum. */ - checksum = ssh_crc32((u_char *) buffer_ptr(&incoming_packet), + checksum = ssh_crc32(buffer_ptr(&incoming_packet), buffer_len(&incoming_packet) - 4); /* Skip padding. */ @@ -753,11 +1036,11 @@ packet_read_poll1(int *payload_len_ptr) /* Test check bytes. */ if (len != buffer_len(&incoming_packet)) - packet_disconnect("packet_read_poll: len %d != buffer_len %d.", + packet_disconnect("packet_read_poll1: len %d != buffer_len %d.", len, buffer_len(&incoming_packet)); - ucp = (u_char *) buffer_ptr(&incoming_packet) + len - 4; - stored_checksum = GET_32BIT(ucp); + cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4; + stored_checksum = get_u32(cp); if (checksum != stored_checksum) packet_disconnect("Corrupted check bytes on input."); buffer_consume_end(&incoming_packet, 4); @@ -770,19 +1053,18 @@ packet_read_poll1(int *payload_len_ptr) buffer_len(&compression_buffer)); } type = buffer_get_char(&incoming_packet); - *payload_len_ptr = buffer_len(&incoming_packet); + if (type < SSH_MSG_MIN || type > SSH_MSG_MAX) + packet_disconnect("Invalid ssh1 packet type: %d", type); return type; } static int -packet_read_poll2(int *payload_len_ptr) +packet_read_poll2(u_int32_t *seqnr_p) { - static u_int32_t seqnr = 0; static u_int packet_length = 0; u_int padlen, need; - u_char *macbuf, *ucp, type; - char *cp; - int maclen, block_size; + u_char *macbuf, *cp, type; + u_int maclen, block_size; Enc *enc = NULL; Mac *mac = NULL; Comp *comp = NULL; @@ -793,7 +1075,7 @@ packet_read_poll2(int *payload_len_ptr) comp = &newkeys[MODE_IN]->comp; } maclen = mac && mac->enabled ? mac->mac_len : 0; - block_size = enc ? enc->cipher->block_size : 8; + block_size = enc ? enc->block_size : 8; if (packet_length == 0) { /* @@ -803,16 +1085,18 @@ packet_read_poll2(int *payload_len_ptr) if (buffer_len(&input) < block_size) return SSH_MSG_NONE; buffer_clear(&incoming_packet); - buffer_append_space(&incoming_packet, &cp, block_size); - cipher_decrypt(&receive_context, cp, buffer_ptr(&input), + cp = buffer_append_space(&incoming_packet, block_size); + cipher_crypt(&receive_context, cp, buffer_ptr(&input), block_size); - ucp = (u_char *) buffer_ptr(&incoming_packet); - packet_length = GET_32BIT(ucp); + cp = buffer_ptr(&incoming_packet); + packet_length = get_u32(cp); if (packet_length < 1 + 4 || packet_length > 256 * 1024) { +#ifdef PACKET_DEBUG buffer_dump(&incoming_packet); - packet_disconnect("Bad packet length %d.", packet_length); +#endif + packet_disconnect("Bad packet length %u.", packet_length); } - DBG(debug("input: packet len %d", packet_length+4)); + DBG(debug("input: packet len %u", packet_length+4)); buffer_consume(&input, block_size); } /* we have a partial packet of block_size bytes */ @@ -832,28 +1116,34 @@ packet_read_poll2(int *payload_len_ptr) fprintf(stderr, "read_poll enc/full: "); buffer_dump(&input); #endif - buffer_append_space(&incoming_packet, &cp, need); - cipher_decrypt(&receive_context, cp, buffer_ptr(&input), need); + cp = buffer_append_space(&incoming_packet, need); + cipher_crypt(&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, - (u_char *) buffer_ptr(&incoming_packet), + macbuf = mac_compute(mac, p_read.seqnr, + buffer_ptr(&incoming_packet), buffer_len(&incoming_packet)); if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0) packet_disconnect("Corrupted MAC on input."); - DBG(debug("MAC #%d ok", seqnr)); + DBG(debug("MAC #%d ok", p_read.seqnr)); buffer_consume(&input, mac->mac_len); } - if (++seqnr == 0) - log("incoming seqnr wraps around"); + if (seqnr_p != NULL) + *seqnr_p = p_read.seqnr; + if (++p_read.seqnr == 0) + logit("incoming seqnr wraps around"); + if (++p_read.packets == 0) + if (!(datafellows & SSH_BUG_NOREKEY)) + fatal("XXX too many packets with same key"); + p_read.blocks += (packet_length + 4) / block_size; /* get padlen */ - cp = buffer_ptr(&incoming_packet) + 4; - padlen = (u_char) *cp; + cp = buffer_ptr(&incoming_packet); + padlen = cp[4]; DBG(debug("input: padlen %d", padlen)); if (padlen < 4) packet_disconnect("Corrupted padlen %d on input.", padlen); @@ -869,16 +1159,20 @@ packet_read_poll2(int *payload_len_ptr) buffer_clear(&incoming_packet); buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), buffer_len(&compression_buffer)); - DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet))); + DBG(debug("input: len after de-compress %d", + buffer_len(&incoming_packet))); } /* * get packet type, implies consume. * 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); - *payload_len_ptr = buffer_len(&incoming_packet); + 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); @@ -889,18 +1183,18 @@ packet_read_poll2(int *payload_len_ptr) } int -packet_read_poll(int *payload_len_ptr) +packet_read_poll_seqnr(u_int32_t *seqnr_p) { - int reason; + u_int reason, seqnr; u_char type; char *msg; for (;;) { if (compat20) { - type = packet_read_poll2(payload_len_ptr); + type = packet_read_poll2(seqnr_p); if (type) DBG(debug("received packet type %d", type)); - switch(type) { + switch (type) { case SSH2_MSG_IGNORE: break; case SSH2_MSG_DEBUG: @@ -914,18 +1208,22 @@ packet_read_poll(int *payload_len_ptr) 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); + logit("Received disconnect from %s: %u: %.400s", + get_remote_ipaddr(), reason, msg); xfree(msg); - fatal_cleanup(); + cleanup_exit(255); + break; + case SSH2_MSG_UNIMPLEMENTED: + seqnr = packet_get_int(); + debug("Received SSH2_MSG_UNIMPLEMENTED for %u", + seqnr); break; default: return type; - break; } } else { - type = packet_read_poll1(payload_len_ptr); - switch(type) { + type = packet_read_poll1(); + switch (type) { case SSH_MSG_IGNORE: break; case SSH_MSG_DEBUG: @@ -935,21 +1233,25 @@ packet_read_poll(int *payload_len_ptr) break; case SSH_MSG_DISCONNECT: msg = packet_get_string(NULL); - log("Received disconnect from %s: %.400s", get_remote_ipaddr(), - msg); - fatal_cleanup(); - xfree(msg); + logit("Received disconnect from %s: %.400s", + get_remote_ipaddr(), msg); + cleanup_exit(255); break; default: if (type) 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. @@ -964,9 +1266,10 @@ packet_process_incoming(const char *buf, u_int len) /* Returns a character from the packet. */ u_int -packet_get_char() +packet_get_char(void) { char ch; + buffer_get(&incoming_packet, &ch, 1); return (u_char) ch; } @@ -974,7 +1277,7 @@ packet_get_char() /* Returns an integer from the packet data. */ u_int -packet_get_int() +packet_get_int(void) { return buffer_get_int(&incoming_packet); } @@ -985,21 +1288,22 @@ packet_get_int() */ void -packet_get_bignum(BIGNUM * value, int *length_ptr) +packet_get_bignum(BIGNUM * value) { - *length_ptr = buffer_get_bignum(&incoming_packet, value); + buffer_get_bignum(&incoming_packet, value); } void -packet_get_bignum2(BIGNUM * value, int *length_ptr) +packet_get_bignum2(BIGNUM * value) { - *length_ptr = buffer_get_bignum2(&incoming_packet, value); + buffer_get_bignum2(&incoming_packet, value); } -char * -packet_get_raw(int *length_ptr) +void * +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; return buffer_ptr(&incoming_packet); @@ -1018,21 +1322,12 @@ packet_remaining(void) * integer into which the length of the string is stored. */ -char * +void * packet_get_string(u_int *length_ptr) { return buffer_get_string(&incoming_packet, length_ptr); } -/*modified by binhe*/ -/* Clears incoming data buffer */ - -void packet_get_all(void) -{ - buffer_clear(&incoming_packet); -} -/*end of modification*/ - /* * 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 @@ -1081,6 +1376,7 @@ packet_disconnect(const char *fmt,...) char buf[1024]; va_list args; static int disconnecting = 0; + if (disconnecting) /* Guard against recursive invocations. */ fatal("packet_disconnect called recursively."); disconnecting = 1; @@ -1093,6 +1389,9 @@ packet_disconnect(const char *fmt,...) vsnprintf(buf, sizeof(buf), fmt, args); va_end(args); + /* Display the error locally */ + logit("Disconnecting: %.100s", buf); + /* Send the disconnect message to the other side, and wait for it to get sent. */ if (compat20) { packet_start(SSH2_MSG_DISCONNECT); @@ -1111,18 +1410,16 @@ packet_disconnect(const char *fmt,...) /* Close the connection. */ packet_close(); - - /* Display the error locally and exit. */ - log("Disconnecting: %.100s", buf); - fatal_cleanup(); + cleanup_exit(255); } /* Checks if there is any buffered output, and tries to write some of the output. */ void -packet_write_poll() +packet_write_poll(void) { int len = buffer_len(&output); + if (len > 0) { len = write(connection_out, buffer_ptr(&output), len); if (len <= 0) { @@ -1141,11 +1438,11 @@ packet_write_poll() */ void -packet_write_wait() +packet_write_wait(void) { fd_set *setp; - 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()) { @@ -1163,7 +1460,7 @@ packet_write_wait() /* Returns true if there is buffered data to write to the connection. */ int -packet_have_data_to_write() +packet_have_data_to_write(void) { return buffer_len(&output) != 0; } @@ -1171,7 +1468,7 @@ packet_have_data_to_write() /* Returns true if there is not too much data to write to the connection. */ int -packet_not_very_much_data_to_write() +packet_not_very_much_data_to_write(void) { if (interactive_mode) return buffer_len(&output) < 16384; @@ -1179,17 +1476,29 @@ packet_not_very_much_data_to_write() return buffer_len(&output) < 128 * 1024; } + +static void +packet_set_tos(int interactive) +{ +#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) + int tos = interactive ? IPTOS_LOWDELAY : IPTOS_THROUGHPUT; + + if (!packet_connection_is_on_socket() || + !packet_connection_is_ipv4()) + return; + if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &tos, + sizeof(tos)) < 0) + error("setsockopt IP_TOS %d: %.100s:", + tos, strerror(errno)); +#endif +} + /* Informs that the current session is interactive. Sets IP flags for that. */ void packet_set_interactive(int interactive) { static int called = 0; -#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) - int lowdelay = IPTOS_LOWDELAY; - int throughput = IPTOS_THROUGHPUT; -#endif - int on = 1; if (called) return; @@ -1201,57 +1510,30 @@ packet_set_interactive(int interactive) /* Only set socket options if using a socket. */ if (!packet_connection_is_on_socket()) return; - /* - * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only - */ - if (interactive) { - /* - * Set IP options for an interactive connection. Use - * IPTOS_LOWDELAY and TCP_NODELAY. - */ -#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) - if (packet_connection_is_ipv4()) { - if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, - (void *) &lowdelay, sizeof(lowdelay)) < 0) - error("setsockopt IPTOS_LOWDELAY: %.100s", - strerror(errno)); - } -#endif - if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on, - sizeof(on)) < 0) - error("setsockopt TCP_NODELAY: %.100s", strerror(errno)); - } else if (packet_connection_is_ipv4()) { - /* - * Set IP options for a non-interactive connection. Use - * IPTOS_THROUGHPUT. - */ -#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) - if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput, - sizeof(throughput)) < 0) - error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno)); -#endif - } + set_nodelay(connection_in); + packet_set_tos(interactive); } /* Returns true if the current connection is interactive. */ int -packet_is_interactive() +packet_is_interactive(void) { return interactive_mode; } int -packet_set_maxsize(int s) +packet_set_maxsize(u_int s) { static int called = 0; + if (called) { - log("packet_set_maxsize: called twice: old %d new %d", + logit("packet_set_maxsize: called twice: old %d new %d", max_packet_size, s); return -1; } if (s < 4 * 1024 || s > 1024 * 1024) { - log("packet_set_maxsize: bad size %d", s); + logit("packet_set_maxsize: bad size %d", s); return -1; } called = 1; @@ -1281,15 +1563,58 @@ 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++) { + 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; + } +} +int rekey_requested = 0; + +void +packet_request_rekeying(void) +{ + rekey_requested = 1; +} + +#define MAX_PACKETS (1U<<31) +int +packet_need_rekeying(void) +{ + if (datafellows & SSH_BUG_NOREKEY) + return 0; + if (rekey_requested == 1) + { + rekey_requested = 0; + return 1; } + return + (p_send.packets > MAX_PACKETS) || + (p_read.packets > MAX_PACKETS) || + (max_blocks_out && (p_send.blocks > max_blocks_out)) || + (max_blocks_in && (p_read.blocks > max_blocks_in)); +} + +void +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; }