X-Git-Url: http://andersk.mit.edu/gitweb/gssapi-openssh.git/blobdiff_plain/540d72c3b0c580a78191cf0b5123c07e9e95d3b4..e8439bd392cea547976fcfe4087a15538ac7c8f3:/openssh/packet.c diff --git a/openssh/packet.c b/openssh/packet.c index daae9ff..cab44bc 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 @@ -37,26 +38,39 @@ */ #include "includes.h" -RCSID("$OpenBSD: packet.c,v 1.112 2003/09/23 20:17:11 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" @@ -116,6 +130,12 @@ 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 { @@ -154,8 +174,10 @@ 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, "", 0, NULL, 0, CIPHER_ENCRYPT); - cipher_init(&receive_context, none, "", 0, NULL, 0, CIPHER_DECRYPT); + 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; @@ -250,6 +272,7 @@ packet_get_keyiv_len(int mode) return (cipher_get_keyiv_len(cc)); } + void packet_set_iv(int mode, u_char *dat) { @@ -262,6 +285,7 @@ packet_set_iv(int mode, u_char *dat) cipher_set_keyiv(cc, dat); } + int packet_get_ssh1_cipher(void) { @@ -317,13 +341,10 @@ void 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. */ @@ -466,31 +487,37 @@ packet_put_char(int 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 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 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) { @@ -508,7 +535,7 @@ packet_send1(void) 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 @@ -534,9 +561,9 @@ packet_send1(void) 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); @@ -544,7 +571,7 @@ packet_send1(void) /* Add check bytes. */ 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 @@ -553,7 +580,7 @@ packet_send1(void) #endif /* Append to output. */ - PUT_32BIT(buf, len); + put_u32(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), @@ -567,7 +594,7 @@ 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. */ @@ -581,18 +608,18 @@ set_newkeys(int mode) Comp *comp; CipherContext *cc; u_int64_t *max_blocks; - int encrypt; + int crypt_type; debug2("set_newkeys: mode %d", mode); if (mode == MODE_OUT) { cc = &send_context; - encrypt = CIPHER_ENCRYPT; + crypt_type = CIPHER_ENCRYPT; p_send.packets = p_send.blocks = 0; max_blocks = &max_blocks_out; } else { cc = &receive_context; - encrypt = CIPHER_DECRYPT; + crypt_type = CIPHER_DECRYPT; p_read.packets = p_read.blocks = 0; max_blocks = &max_blocks_in; } @@ -602,7 +629,7 @@ set_newkeys(int mode) 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); @@ -617,15 +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->key_len, - enc->iv, enc->block_size, encrypt); + 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); */ - if (comp->type != 0 && comp->enabled == 0) { + 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); @@ -646,16 +676,48 @@ set_newkeys(int mode) } /* - * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) + * 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 int packet_send2_wrapped(void) { u_char type, *cp, *macbuf = NULL; u_char padlen, pad; 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; @@ -714,9 +776,9 @@ packet_send2_wrapped(void) /* 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 */ @@ -725,7 +787,7 @@ packet_send2_wrapped(void) /* packet_length includes payload, padding and padding length field */ packet_length = buffer_len(&outgoing_packet) - 4; cp = buffer_ptr(&outgoing_packet); - PUT_32BIT(cp, packet_length); + put_u32(cp, packet_length); cp[4] = padlen; DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); @@ -742,7 +804,7 @@ packet_send2_wrapped(void) 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); @@ -758,11 +820,15 @@ packet_send2_wrapped(void) if (type == SSH2_MSG_NEWKEYS) set_newkeys(MODE_OUT); + else if (type == SSH2_MSG_USERAUTH_SUCCESS && server_side) + packet_enable_delayed_compress(); + return(packet_length); } -static void +static int packet_send2(void) { + static int packet_length = 0; static int rekeying = 0; struct packet *p; u_char type, *cp; @@ -780,7 +846,7 @@ packet_send2(void) memcpy(&p->payload, &outgoing_packet, sizeof(Buffer)); buffer_init(&outgoing_packet); TAILQ_INSERT_TAIL(&outgoing, p, next); - return; + return(sizeof(Buffer)); } } @@ -788,7 +854,7 @@ packet_send2(void) if (type == SSH2_MSG_KEXINIT) rekeying = 1; - packet_send2_wrapped(); + packet_length = packet_send2_wrapped(); /* after a NEWKEYS message we can send the complete queue */ if (type == SSH2_MSG_NEWKEYS) { @@ -801,19 +867,22 @@ packet_send2(void) sizeof(Buffer)); TAILQ_REMOVE(&outgoing, p, next); xfree(p); - packet_send2_wrapped(); + packet_length += packet_send2_wrapped(); } } + return(packet_length); } -void +int packet_send(void) { + int packet_len = 0; if (compat20) - packet_send2(); + packet_len = packet_send2(); else packet_send1(); DBG(debug("packet_send done")); + return(packet_len); } /* @@ -830,7 +899,7 @@ packet_read_seqnr(u_int32_t *seqnr_p) 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. */ @@ -921,7 +990,7 @@ packet_read_poll1(void) return SSH_MSG_NONE; /* Get length of incoming packet. */ cp = buffer_ptr(&input); - len = GET_32BIT(cp); + len = get_u32(cp); if (len < 1 + 2 + 2 || len > 256 * 1024) packet_disconnect("Bad packet length %u.", len); padded_len = (len + 8) & ~7; @@ -940,9 +1009,16 @@ packet_read_poll1(void) * (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"); + 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); @@ -969,7 +1045,7 @@ packet_read_poll1(void) len, buffer_len(&incoming_packet)); cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4; - stored_checksum = GET_32BIT(cp); + stored_checksum = get_u32(cp); if (checksum != stored_checksum) packet_disconnect("Corrupted check bytes on input."); buffer_consume_end(&incoming_packet, 4); @@ -982,6 +1058,8 @@ packet_read_poll1(void) buffer_len(&compression_buffer)); } type = buffer_get_char(&incoming_packet); + if (type < SSH_MSG_MIN || type > SSH_MSG_MAX) + packet_disconnect("Invalid ssh1 packet type: %d", type); return type; } @@ -991,7 +1069,7 @@ packet_read_poll2(u_int32_t *seqnr_p) static u_int packet_length = 0; u_int padlen, need; u_char *macbuf, *cp, type; - int maclen, block_size; + u_int maclen, block_size; Enc *enc = NULL; Mac *mac = NULL; Comp *comp = NULL; @@ -1016,7 +1094,7 @@ packet_read_poll2(u_int32_t *seqnr_p) cipher_crypt(&receive_context, cp, buffer_ptr(&input), block_size); cp = buffer_ptr(&incoming_packet); - packet_length = GET_32BIT(cp); + packet_length = get_u32(cp); if (packet_length < 1 + 4 || packet_length > 256 * 1024) { #ifdef PACKET_DEBUG buffer_dump(&incoming_packet); @@ -1094,8 +1172,12 @@ packet_read_poll2(u_int32_t *seqnr_p) * 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); + 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); @@ -1143,7 +1225,6 @@ packet_read_poll_seqnr(u_int32_t *seqnr_p) break; default: return type; - break; } } else { type = packet_read_poll1(); @@ -1160,13 +1241,11 @@ packet_read_poll_seqnr(u_int32_t *seqnr_p) logit("Received disconnect from %s: %.400s", get_remote_ipaddr(), msg); cleanup_exit(255); - xfree(msg); break; default: if (type) DBG(debug("received packet type %d", type)); return type; - break; } } } @@ -1226,9 +1305,9 @@ packet_get_bignum2(BIGNUM * value) } void * -packet_get_raw(int *length_ptr) +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; @@ -1341,21 +1420,23 @@ packet_disconnect(const char *fmt,...) /* Checks if there is any buffered output, and tries to write some of the output. */ -void +int packet_write_poll(void) { - int len = buffer_len(&output); + int len = 0; + len = buffer_len(&output); if (len > 0) { len = write(connection_out, buffer_ptr(&output), len); if (len <= 0) { if (errno == EAGAIN) - return; + return (0); else fatal("Write failed: %.100s", strerror(errno)); } buffer_consume(&output, len); } + return(len); } /* @@ -1363,14 +1444,15 @@ packet_write_poll(void) * written. */ -void +int packet_write_wait(void) { fd_set *setp; + u_int bytes_sent = 0; - setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) * + setp = (fd_set *)xcalloc(howmany(connection_out + 1, NFDBITS), sizeof(fd_mask)); - packet_write_poll(); + bytes_sent += packet_write_poll(); while (packet_have_data_to_write()) { memset(setp, 0, howmany(connection_out + 1, NFDBITS) * sizeof(fd_mask)); @@ -1378,9 +1460,10 @@ packet_write_wait(void) while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 && (errno == EAGAIN || errno == EINTR)) ; - packet_write_poll(); + bytes_sent += packet_write_poll(); } xfree(setp); + return (bytes_sent); } /* Returns true if there is buffered data to write to the connection. */ @@ -1436,8 +1519,7 @@ packet_set_interactive(int interactive) /* Only set socket options if using a socket. */ if (!packet_connection_is_on_socket()) return; - if (interactive) - set_nodelay(connection_in); + set_nodelay(connection_in); packet_set_tos(interactive); } @@ -1449,7 +1531,7 @@ packet_is_interactive(void) return interactive_mode; } -u_int +int packet_set_maxsize(u_int s) { static int called = 0; @@ -1490,25 +1572,37 @@ 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++) { if (i % 4 == 0) - rand = arc4random(); - packet_put_char(rand & 0xff); - rand >>= 8; + rnd = arc4random(); + packet_put_char((u_char)rnd & 0xff); + rnd >>= 8; } } -#define MAX_PACKETS (1<<31) +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) || @@ -1521,3 +1615,21 @@ 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; +} + +int +packet_authentication_state(void) +{ + return(after_authentication); +}