=================================================================== RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/packet.c,v retrieving revision 1.102 retrieving revision 1.103 diff -u -r1.102 -r1.103 --- src/usr.bin/ssh/packet.c 2002/12/10 19:47:14 1.102 +++ src/usr.bin/ssh/packet.c 2003/04/01 10:10:23 1.103 @@ -37,8 +37,10 @@ */ #include "includes.h" -RCSID("$OpenBSD: packet.c,v 1.102 2002/12/10 19:47:14 markus Exp $"); +RCSID("$OpenBSD: packet.c,v 1.103 2003/04/01 10:10:23 markus Exp $"); +#include + #include "xmalloc.h" #include "buffer.h" #include "packet.h" @@ -116,9 +118,15 @@ /* 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]; static u_int ssh1_keylen; @@ -126,6 +134,13 @@ /* 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 @@ 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); @@ -254,22 +270,26 @@ 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 */ @@ -557,6 +577,7 @@ Mac *mac; Comp *comp; CipherContext *cc; + u_int64_t *max_blocks; int encrypt; debug2("set_newkeys: mode %d", mode); @@ -564,9 +585,13 @@ 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"); @@ -605,13 +630,16 @@ buffer_compress_init_recv(); comp->enabled = 1; } + *max_blocks = ((u_int64_t)1 << (enc->block_size*2)); + 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; @@ -693,10 +721,10 @@ /* 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)); @@ -710,14 +738,64 @@ buffer_dump(&output); #endif /* increment sequence number for outgoing packets */ - if (++send_seqnr == 0) + if (++p_send.seqnr == 0) log("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) { @@ -961,18 +1039,22 @@ * 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) + *seqnr_p = p_read.seqnr; + if (++p_read.seqnr == 0) log("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); @@ -1405,4 +1487,23 @@ packet_put_char(rand & 0xff); 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; }