X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/a5efa1bbdb76c6234fd56037a3220fed54a7dfb7..e62075983f11ef51d9586f304302bcfece42f63c:/packet.c diff --git a/packet.c b/packet.c index 402259a9..960675a9 100644 --- a/packet.c +++ b/packet.c @@ -13,7 +13,7 @@ * * * SSH2 packet format added by Markus Friedl. - * Copyright (c) 2000 Markus Friedl. All rights reserved. + * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -37,7 +37,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: packet.c,v 1.64 2001/05/31 10:30:16 markus Exp $"); +RCSID("$OpenBSD: packet.c,v 1.85 2002/01/18 18:14:17 stevesk Exp $"); #include "xmalloc.h" #include "buffer.h" @@ -115,6 +115,9 @@ static int interactive_mode = 0; /* Session key information for Encryption and MAC */ Newkeys *newkeys[MODE_MAX]; +/* roundup current message to extra_pad bytes */ +static u_char extra_pad = 0; + /* * Sets the descriptors used for communication. Disables encryption until * packet_set_encryption_key is called. @@ -127,8 +130,8 @@ packet_set_connection(int fd_in, int fd_out) 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, "", 0, NULL, 0); + cipher_init(&receive_context, none, "", 0, NULL, 0); newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL; if (!initialized) { initialized = 1; @@ -144,7 +147,7 @@ packet_set_connection(int fd_in, int fd_out) /* 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; @@ -170,7 +173,7 @@ packet_connection_is_on_socket() /* 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); @@ -186,7 +189,7 @@ packet_connection_is_ipv4() /* 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) @@ -201,7 +204,7 @@ packet_set_nonblocking() /* Returns the socket used for reading. */ int -packet_get_connection_in() +packet_get_connection_in(void) { return connection_in; } @@ -209,7 +212,7 @@ packet_get_connection_in() /* Returns the descriptor used for writing. */ int -packet_get_connection_out() +packet_get_connection_out(void) { return connection_out; } @@ -217,7 +220,7 @@ packet_get_connection_out() /* Closes the connection and clears and frees internal data structures. */ void -packet_close() +packet_close(void) { if (!initialized) return; @@ -250,7 +253,7 @@ 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; } @@ -260,8 +263,8 @@ packet_get_protocol_flags() * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. */ -void -packet_init_compression() +static void +packet_init_compression(void) { if (compression_buffer_ready == 1) return; @@ -326,17 +329,17 @@ 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_string(&outgoing_packet, str, strlen(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); } @@ -356,7 +359,7 @@ packet_put_bignum2(BIGNUM * value) * encrypts the packet before sending. */ -void +static void packet_send1(void) { char buf[8], *cp; @@ -377,7 +380,7 @@ 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; @@ -396,7 +399,7 @@ packet_send1(void) 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); buffer_append(&outgoing_packet, buf, 4); @@ -409,9 +412,9 @@ packet_send1(void) /* Append to output. */ PUT_32BIT(buf, len); buffer_append(&output, buf, 4); - buffer_append_space(&output, &cp, buffer_len(&outgoing_packet)); + cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet), - buffer_len(&outgoing_packet)); + buffer_len(&outgoing_packet)); #ifdef PACKET_DEBUG fprintf(stderr, "encrypted: "); @@ -427,7 +430,7 @@ packet_send1(void) */ } -void +static void set_newkeys(int mode) { Enc *enc; @@ -480,14 +483,15 @@ set_newkeys(int mode) /* * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) */ -void +static void packet_send2(void) { static u_int32_t seqnr = 0; u_char type, *ucp, *macbuf = NULL; + u_char padlen, pad; char *cp; u_int packet_length = 0; - u_int i, padlen, len; + u_int i, len; u_int32_t rand = 0; Enc *enc = NULL; Mac *mac = NULL; @@ -501,7 +505,7 @@ packet_send2(void) } block_size = enc ? enc->cipher->block_size : 8; - ucp = (u_char *) buffer_ptr(&outgoing_packet); + ucp = buffer_ptr(&outgoing_packet); type = ucp[5]; #ifdef PACKET_DEBUG @@ -533,7 +537,16 @@ packet_send2(void) padlen = block_size - (len % block_size); if (padlen < 4) padlen += block_size; - buffer_append_space(&outgoing_packet, &cp, padlen); + 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 && enc->cipher->number != SSH_CIPHER_NONE) { /* random padding */ for (i = 0; i < padlen; i++) { @@ -548,7 +561,7 @@ 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); + ucp = buffer_ptr(&outgoing_packet); PUT_32BIT(ucp, packet_length); ucp[4] = padlen; DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); @@ -556,12 +569,12 @@ packet_send2(void) /* 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), + buffer_ptr(&outgoing_packet), buffer_len(&outgoing_packet)); DBG(debug("done calc MAC out #%d", seqnr)); } /* encrypt packet and append to output buffer. */ - buffer_append_space(&output, &cp, buffer_len(&outgoing_packet)); + cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet), buffer_len(&outgoing_packet)); /* append unencrypted MAC */ @@ -581,7 +594,7 @@ packet_send2(void) } void -packet_send() +packet_send(void) { if (compat20) packet_send2(); @@ -597,7 +610,7 @@ packet_send() */ int -packet_read(int *payload_len_ptr) +packet_read_seqnr(u_int32_t *seqnr_p) { int type, len; fd_set *setp; @@ -613,13 +626,13 @@ 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); @@ -652,17 +665,23 @@ 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); @@ -675,16 +694,10 @@ 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 */ -int -packet_read_poll1(int *payload_len_ptr) +static int +packet_read_poll1(void) { u_int len, padded_len; u_char *ucp, type; @@ -695,7 +708,7 @@ packet_read_poll1(int *payload_len_ptr) if (buffer_len(&input) < 4 + 8) return SSH_MSG_NONE; /* Get length of incoming packet. */ - ucp = (u_char *) buffer_ptr(&input); + ucp = buffer_ptr(&input); len = GET_32BIT(ucp); if (len < 1 + 2 + 2 || len > 256 * 1024) packet_disconnect("Bad packet length %d.", len); @@ -721,7 +734,7 @@ packet_read_poll1(int *payload_len_ptr) /* Decrypt data to incoming_packet. */ buffer_clear(&incoming_packet); - buffer_append_space(&incoming_packet, &cp, padded_len); + cp = buffer_append_space(&incoming_packet, padded_len); cipher_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len); buffer_consume(&input, padded_len); @@ -732,7 +745,7 @@ 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. */ @@ -740,10 +753,10 @@ 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; + ucp = (u_char *)buffer_ptr(&incoming_packet) + len - 4; stored_checksum = GET_32BIT(ucp); if (checksum != stored_checksum) packet_disconnect("Corrupted check bytes on input."); @@ -757,12 +770,11 @@ packet_read_poll1(int *payload_len_ptr) buffer_len(&compression_buffer)); } type = buffer_get_char(&incoming_packet); - *payload_len_ptr = buffer_len(&incoming_packet); return type; } -int -packet_read_poll2(int *payload_len_ptr) +static int +packet_read_poll2(u_int32_t *seqnr_p) { static u_int32_t seqnr = 0; static u_int packet_length = 0; @@ -790,10 +802,10 @@ 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); + cp = buffer_append_space(&incoming_packet, block_size); cipher_decrypt(&receive_context, cp, buffer_ptr(&input), block_size); - ucp = (u_char *) buffer_ptr(&incoming_packet); + ucp = buffer_ptr(&incoming_packet); packet_length = GET_32BIT(ucp); if (packet_length < 1 + 4 || packet_length > 256 * 1024) { buffer_dump(&incoming_packet); @@ -819,7 +831,7 @@ packet_read_poll2(int *payload_len_ptr) fprintf(stderr, "read_poll enc/full: "); buffer_dump(&input); #endif - buffer_append_space(&incoming_packet, &cp, need); + cp = buffer_append_space(&incoming_packet, need); cipher_decrypt(&receive_context, cp, buffer_ptr(&input), need); buffer_consume(&input, need); /* @@ -828,18 +840,21 @@ packet_read_poll2(int *payload_len_ptr) */ if (mac && mac->enabled) { macbuf = mac_compute(mac, seqnr, - (u_char *) buffer_ptr(&incoming_packet), + 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)); 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) + 4; + cp = buffer_ptr(&incoming_packet); + cp += 4; padlen = (u_char) *cp; DBG(debug("input: padlen %d", padlen)); if (padlen < 4) @@ -865,7 +880,6 @@ packet_read_poll2(int *payload_len_ptr) type = buffer_get_char(&incoming_packet); if (type == SSH2_MSG_NEWKEYS) set_newkeys(MODE_IN); - *payload_len_ptr = buffer_len(&incoming_packet); #ifdef PACKET_DEBUG fprintf(stderr, "read/plain[%d]:\r\n", type); buffer_dump(&incoming_packet); @@ -876,18 +890,18 @@ 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; + 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: @@ -906,13 +920,17 @@ packet_read_poll(int *payload_len_ptr) 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(payload_len_ptr); - switch(type) { + type = packet_read_poll1(); + switch (type) { case SSH_MSG_IGNORE: break; case SSH_MSG_DEBUG: @@ -937,6 +955,12 @@ packet_read_poll(int *payload_len_ptr) } } +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. @@ -951,7 +975,7 @@ 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); @@ -961,7 +985,7 @@ 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); } @@ -972,18 +996,18 @@ 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 * +void * packet_get_raw(int *length_ptr) { int bytes = buffer_len(&incoming_packet); @@ -1005,7 +1029,7 @@ 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); @@ -1079,13 +1103,13 @@ packet_disconnect(const char *fmt,...) packet_put_cstring(""); } else { packet_start(SSH_MSG_DISCONNECT); - packet_put_string(buf, strlen(buf)); + packet_put_cstring(buf); } packet_send(); packet_write_wait(); /* Stop listening for connections. */ - channel_stop_listening(); + channel_close_all(); /* Close the connection. */ packet_close(); @@ -1098,7 +1122,7 @@ packet_disconnect(const char *fmt,...) /* 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) { @@ -1119,7 +1143,7 @@ packet_write_poll() */ void -packet_write_wait() +packet_write_wait(void) { fd_set *setp; @@ -1141,7 +1165,7 @@ 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; } @@ -1149,7 +1173,7 @@ 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; @@ -1214,7 +1238,7 @@ packet_set_interactive(int interactive) /* Returns true if the current connection is interactive. */ int -packet_is_interactive() +packet_is_interactive(void) { return interactive_mode; } @@ -1232,11 +1256,19 @@ packet_set_maxsize(int s) log("packet_set_maxsize: bad size %d", s); return -1; } - log("packet_set_maxsize: setting to %d", s); + called = 1; + debug("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 * @@ -1248,41 +1280,6 @@ packet_set_maxsize(int s) * required to send them. This message can be used as an additional * protection measure against advanced traffic analysis techniques. */ -/* size of current + ignore message should be n*sumlen bytes (w/o mac) */ -void -packet_inject_ignore(int sumlen) -{ - int blocksize, padlen, have, need, nb, mini, nbytes; - Enc *enc = NULL; - - if (compat20 == 0) - return; - - have = buffer_len(&outgoing_packet); - debug2("packet_inject_ignore: current %d", have); - if (newkeys[MODE_OUT] != NULL) - enc = &newkeys[MODE_OUT]->enc; - blocksize = enc ? enc->cipher->block_size : 8; - padlen = blocksize - (have % blocksize); - if (padlen < 4) - padlen += blocksize; - have += padlen; - have /= blocksize; /* # of blocks for current message */ - - nb = roundup(sumlen, blocksize) / blocksize; /* blocks for both */ - mini = roundup(5+1+4+4, blocksize) / blocksize; /* minsize ignore msg */ - need = nb - (have % nb); /* blocks for ignore */ - if (need <= mini) - need += nb; - nbytes = (need - mini) * blocksize; /* size of ignore payload */ - debug2("packet_inject_ignore: block %d have %d nb %d mini %d need %d", - blocksize, have, nb, mini, need); - - /* enqueue current message and append a ignore message */ - packet_send(); - packet_send_ignore(nbytes); -} - void packet_send_ignore(int nbytes) { @@ -1291,7 +1288,7 @@ packet_send_ignore(int nbytes) 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);