diff options
Diffstat (limited to 'crypto/openssh/packet.c')
-rw-r--r-- | crypto/openssh/packet.c | 181 |
1 files changed, 147 insertions, 34 deletions
diff --git a/crypto/openssh/packet.c b/crypto/openssh/packet.c index 77860d6..02b629f 100644 --- a/crypto/openssh/packet.c +++ b/crypto/openssh/packet.c @@ -37,7 +37,9 @@ */ #include "includes.h" -RCSID("$OpenBSD: packet.c,v 1.104 2003/04/01 10:22:21 markus Exp $"); +RCSID("$OpenBSD: packet.c,v 1.110 2003/09/19 09:02:02 markus Exp $"); + +#include "openbsd-compat/sys-queue.h" #include "xmalloc.h" #include "buffer.h" @@ -106,7 +108,7 @@ 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; @@ -116,8 +118,14 @@ static int interactive_mode = 0; /* Session key information for Encryption and MAC */ Newkeys *newkeys[MODE_MAX]; -static u_int32_t read_seqnr = 0; -static u_int32_t send_seqnr = 0; +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]; @@ -126,6 +134,13 @@ 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. @@ -148,6 +163,7 @@ 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); @@ -249,27 +265,31 @@ packet_set_iv(int mode, u_char *dat) cipher_set_keyiv(cc, dat); } int -packet_get_ssh1_cipher() +packet_get_ssh1_cipher(void) { return (cipher_get_number(receive_context.cipher)); } - -u_int32_t -packet_get_seqnr(int mode) +void +packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets) { - return (mode == MODE_IN ? read_seqnr : send_seqnr); + struct packet_state *state; + + state = (mode == MODE_IN) ? &p_read : &p_send; + *seqnr = state->seqnr; + *blocks = state->blocks; + *packets = state->packets; } void -packet_set_seqnr(int mode, u_int32_t seqnr) +packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets) { - if (mode == MODE_IN) - read_seqnr = seqnr; - else if (mode == MODE_OUT) - send_seqnr = seqnr; - else - fatal("packet_set_seqnr: bad mode %d", mode); + 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 */ @@ -562,6 +582,7 @@ set_newkeys(int mode) Mac *mac; Comp *comp; CipherContext *cc; + u_int64_t *max_blocks; int encrypt; debug2("set_newkeys: mode %d", mode); @@ -569,9 +590,13 @@ set_newkeys(int mode) if (mode == MODE_OUT) { cc = &send_context; encrypt = CIPHER_ENCRYPT; + p_send.packets = p_send.blocks = 0; + max_blocks = &max_blocks_out; } else { cc = &receive_context; encrypt = CIPHER_DECRYPT; + p_read.packets = p_read.blocks = 0; + max_blocks = &max_blocks_in; } if (newkeys[mode] != NULL) { debug("set_newkeys: rekeying"); @@ -610,13 +635,23 @@ 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); } /* * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) */ static void -packet_send2(void) +packet_send2_wrapped(void) { u_char type, *cp, *macbuf = NULL; u_char padlen, pad; @@ -698,10 +733,10 @@ packet_send2(void) /* compute MAC over seqnr and packet(length fields, payload, padding) */ if (mac && mac->enabled) { - macbuf = mac_compute(mac, send_seqnr, + macbuf = mac_compute(mac, p_send.seqnr, buffer_ptr(&outgoing_packet), buffer_len(&outgoing_packet)); - DBG(debug("done calc MAC out #%d", send_seqnr)); + DBG(debug("done calc MAC out #%d", p_send.seqnr)); } /* encrypt packet and append to output buffer. */ cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); @@ -715,14 +750,64 @@ packet_send2(void) buffer_dump(&output); #endif /* increment sequence number for outgoing packets */ - if (++send_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); } +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(void) { @@ -784,7 +869,7 @@ packet_read_seqnr(u_int32_t *seqnr_p) /* Read data from the socket. */ len = read(connection_in, buf, sizeof(buf)); if (len == 0) { - log("Connection closed by %.200s", get_remote_ipaddr()); + logit("Connection closed by %.200s", get_remote_ipaddr()); fatal_cleanup(); } if (len < 0) @@ -935,7 +1020,9 @@ packet_read_poll2(u_int32_t *seqnr_p) cp = buffer_ptr(&incoming_packet); packet_length = GET_32BIT(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); } DBG(debug("input: packet len %u", packet_length+4)); @@ -966,18 +1053,22 @@ packet_read_poll2(u_int32_t *seqnr_p) * increment sequence number for incoming packet */ if (mac && mac->enabled) { - macbuf = mac_compute(mac, read_seqnr, + 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", read_seqnr)); + DBG(debug("MAC #%d ok", p_read.seqnr)); buffer_consume(&input, mac->mac_len); } if (seqnr_p != NULL) - *seqnr_p = read_seqnr; - if (++read_seqnr == 0) - log("incoming seqnr wraps around"); + *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); @@ -1042,7 +1133,7 @@ packet_read_poll_seqnr(u_int32_t *seqnr_p) case SSH2_MSG_DISCONNECT: reason = packet_get_int(); msg = packet_get_string(NULL); - log("Received disconnect from %s: %u: %.400s", + logit("Received disconnect from %s: %u: %.400s", get_remote_ipaddr(), reason, msg); xfree(msg); fatal_cleanup(); @@ -1068,7 +1159,7 @@ packet_read_poll_seqnr(u_int32_t *seqnr_p) break; case SSH_MSG_DISCONNECT: msg = packet_get_string(NULL); - log("Received disconnect from %s: %.400s", + logit("Received disconnect from %s: %.400s", get_remote_ipaddr(), msg); fatal_cleanup(); xfree(msg); @@ -1227,7 +1318,7 @@ packet_disconnect(const char *fmt,...) va_end(args); /* Display the error locally */ - log("Disconnecting: %.100s", buf); + logit("Disconnecting: %.100s", buf); /* Send the disconnect message to the other side, and wait for it to get sent. */ if (compat20) { @@ -1314,6 +1405,8 @@ packet_not_very_much_data_to_write(void) return buffer_len(&output) < 128 * 1024; } + +#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) static void packet_set_tos(int interactive) { @@ -1327,6 +1420,7 @@ packet_set_tos(int interactive) error("setsockopt IP_TOS %d: %.100s:", tos, strerror(errno)); } +#endif /* Informs that the current session is interactive. Sets IP flags for that. */ @@ -1361,18 +1455,18 @@ packet_is_interactive(void) return interactive_mode; } -int -packet_set_maxsize(int s) +u_int +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; @@ -1414,3 +1508,22 @@ packet_send_ignore(int nbytes) rand >>= 8; } } + +#define MAX_PACKETS (1<<31) +int +packet_need_rekeying(void) +{ + if (datafellows & SSH_BUG_NOREKEY) + return 0; + 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; +} |