Mercurial > dropbear
view common-algo.c @ 1306:34e6127ef02e
merge fixes from PuTTY import.c
toint() from misc.c
(revids are from hggit conversion)
changeset: 4620:60a336a6c85c
user: Simon Tatham <[email protected]>
date: Thu Feb 25 20:26:33 2016 +0000
files: import.c
description:
Fix potential segfaults in reading OpenSSH's ASN.1 key format.
The length coming back from ber_read_id_len might have overflowed, so
treat it as potentially negative. Also, while I'm here, accumulate it
inside ber_read_id_len as an unsigned, so as to avoid undefined
behaviour on integer overflow, and toint() it before return.
Thanks to Hanno Böck for spotting this, with the aid of AFL.
(cherry picked from commit 5b7833cd474a24ec098654dcba8cb9509f3bf2c1)
Conflicts:
import.c
(cherry-picker's note: resolving the conflict involved removing an
entire section of the original commit which fixed ECDSA code not
present on this branch)
changeset: 4619:9c6c638d98d8
user: Simon Tatham <[email protected]>
date: Sun Jul 14 10:45:54 2013 +0000
files: import.c ssh.c sshdss.c sshpubk.c sshrsa.c
description:
Tighten up a lot of casts from unsigned to int which are read by one
of the GET_32BIT macros and then used as length fields. Missing bounds
checks against zero have been added, and also I've introduced a helper
function toint() which casts from unsigned to int in such a way as to
avoid C undefined behaviour, since I'm not sure I trust compilers any
more to do the obviously sensible thing.
[originally from svn r9918]
changeset: 4618:3957829f24d3
user: Simon Tatham <[email protected]>
date: Mon Jul 08 22:36:04 2013 +0000
files: import.c sshdss.c sshrsa.c
description:
Add an assortment of extra safety checks.
[originally from svn r9896]
changeset: 4617:2cddee0bce12
user: Jacob Nevins <[email protected]>
date: Wed Dec 07 00:24:45 2005 +0000
files: import.c
description:
Institutional failure to memset() things pointed at rather than pointers.
Things should now be zeroed and memory not leaked. Spotted by Brant Thomsen.
[originally from svn r6476]
changeset: 4616:24ac78a9c71d
user: Simon Tatham <[email protected]>
date: Wed Feb 11 13:58:27 2004 +0000
files: import.c
description:
Jacob's last-minute testing found a couple of trivial bugs in
import.c, and my attempts to reproduce them in cmdgen found another
one there :-)
[originally from svn r3847]
changeset: 4615:088d39a73db0
user: Simon Tatham <[email protected]>
date: Thu Jan 22 18:52:49 2004 +0000
files: import.c
description:
Placate some gcc warnings.
[originally from svn r3761]
changeset: 4614:e4288bad4d93
parent: 1758:108b8924593d
user: Simon Tatham <[email protected]>
date: Fri Oct 03 21:21:23 2003 +0000
files: import.c
description:
My ASN.1 decoder returned wrong IDs for anything above 0x1E! Good
job it's never had to yet. Ahem.
[originally from svn r3479]
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Tue, 12 Jul 2016 23:00:01 +0800 |
parents | eed9376a4ad6 |
children | 2c9dac2d6707 |
line wrap: on
line source
/* * Dropbear SSH * * Copyright (c) 2002,2003 Matt Johnston * Copyright (c) 2004 by Mihnea Stoenescu * All rights reserved. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ #include "includes.h" #include "algo.h" #include "session.h" #include "dbutil.h" #include "dh_groups.h" #include "ltc_prng.h" #include "ecc.h" /* This file (algo.c) organises the ciphers which can be used, and is used to * decide which ciphers/hashes/compression/signing to use during key exchange*/ static int void_cipher(const unsigned char* in, unsigned char* out, unsigned long len, void* UNUSED(cipher_state)) { if (in != out) { memmove(out, in, len); } return CRYPT_OK; } static int void_start(int UNUSED(cipher), const unsigned char* UNUSED(IV), const unsigned char* UNUSED(key), int UNUSED(keylen), int UNUSED(num_rounds), void* UNUSED(cipher_state)) { return CRYPT_OK; } /* Mappings for ciphers, parameters are {&cipher_desc, keysize, blocksize} */ /* Remember to add new ciphers/hashes to regciphers/reghashes too */ #ifdef DROPBEAR_AES256 static const struct dropbear_cipher dropbear_aes256 = {&aes_desc, 32, 16}; #endif #ifdef DROPBEAR_AES128 static const struct dropbear_cipher dropbear_aes128 = {&aes_desc, 16, 16}; #endif #ifdef DROPBEAR_BLOWFISH static const struct dropbear_cipher dropbear_blowfish = {&blowfish_desc, 16, 8}; #endif #ifdef DROPBEAR_TWOFISH256 static const struct dropbear_cipher dropbear_twofish256 = {&twofish_desc, 32, 16}; #endif #ifdef DROPBEAR_TWOFISH128 static const struct dropbear_cipher dropbear_twofish128 = {&twofish_desc, 16, 16}; #endif #ifdef DROPBEAR_3DES static const struct dropbear_cipher dropbear_3des = {&des3_desc, 24, 8}; #endif /* used to indicate no encryption, as defined in rfc2410 */ const struct dropbear_cipher dropbear_nocipher = {NULL, 16, 8}; /* A few void* s are required to silence warnings * about the symmetric_CBC vs symmetric_CTR cipher_state pointer */ #ifdef DROPBEAR_ENABLE_CBC_MODE const struct dropbear_cipher_mode dropbear_mode_cbc = {(void*)cbc_start, (void*)cbc_encrypt, (void*)cbc_decrypt}; #endif /* DROPBEAR_ENABLE_CBC_MODE */ const struct dropbear_cipher_mode dropbear_mode_none = {void_start, void_cipher, void_cipher}; #ifdef DROPBEAR_ENABLE_CTR_MODE /* a wrapper to make ctr_start and cbc_start look the same */ static int dropbear_big_endian_ctr_start(int cipher, const unsigned char *IV, const unsigned char *key, int keylen, int num_rounds, symmetric_CTR *ctr) { return ctr_start(cipher, IV, key, keylen, num_rounds, CTR_COUNTER_BIG_ENDIAN, ctr); } const struct dropbear_cipher_mode dropbear_mode_ctr = {(void*)dropbear_big_endian_ctr_start, (void*)ctr_encrypt, (void*)ctr_decrypt}; #endif /* DROPBEAR_ENABLE_CTR_MODE */ /* Mapping of ssh hashes to libtomcrypt hashes, including keysize etc. {&hash_desc, keysize, hashsize} */ #ifdef DROPBEAR_SHA1_HMAC static const struct dropbear_hash dropbear_sha1 = {&sha1_desc, 20, 20}; #endif #ifdef DROPBEAR_SHA1_96_HMAC static const struct dropbear_hash dropbear_sha1_96 = {&sha1_desc, 20, 12}; #endif #ifdef DROPBEAR_SHA2_256_HMAC static const struct dropbear_hash dropbear_sha2_256 = {&sha256_desc, 32, 32}; #endif #ifdef DROPBEAR_SHA2_512_HMAC static const struct dropbear_hash dropbear_sha2_512 = {&sha512_desc, 64, 64}; #endif #ifdef DROPBEAR_MD5_HMAC static const struct dropbear_hash dropbear_md5 = {&md5_desc, 16, 16}; #endif const struct dropbear_hash dropbear_nohash = {NULL, 16, 0}; /* used initially */ /* The following map ssh names to internal values. * The ordering here is important for the client - the first mode * that is also supported by the server will get used. */ algo_type sshciphers[] = { #ifdef DROPBEAR_ENABLE_CTR_MODE #ifdef DROPBEAR_AES128 {"aes128-ctr", 0, &dropbear_aes128, 1, &dropbear_mode_ctr}, #endif #ifdef DROPBEAR_AES256 {"aes256-ctr", 0, &dropbear_aes256, 1, &dropbear_mode_ctr}, #endif #ifdef DROPBEAR_TWOFISH_CTR /* twofish ctr is conditional as it hasn't been tested for interoperability, see options.h */ #ifdef DROPBEAR_TWOFISH256 {"twofish256-ctr", 0, &dropbear_twofish256, 1, &dropbear_mode_ctr}, #endif #ifdef DROPBEAR_TWOFISH128 {"twofish128-ctr", 0, &dropbear_twofish128, 1, &dropbear_mode_ctr}, #endif #endif /* DROPBEAR_TWOFISH_CTR */ #endif /* DROPBEAR_ENABLE_CTR_MODE */ #ifdef DROPBEAR_ENABLE_CBC_MODE #ifdef DROPBEAR_AES128 {"aes128-cbc", 0, &dropbear_aes128, 1, &dropbear_mode_cbc}, #endif #ifdef DROPBEAR_AES256 {"aes256-cbc", 0, &dropbear_aes256, 1, &dropbear_mode_cbc}, #endif #ifdef DROPBEAR_TWOFISH256 {"twofish256-cbc", 0, &dropbear_twofish256, 1, &dropbear_mode_cbc}, {"twofish-cbc", 0, &dropbear_twofish256, 1, &dropbear_mode_cbc}, #endif #ifdef DROPBEAR_TWOFISH128 {"twofish128-cbc", 0, &dropbear_twofish128, 1, &dropbear_mode_cbc}, #endif #ifdef DROPBEAR_3DES {"3des-ctr", 0, &dropbear_3des, 1, &dropbear_mode_ctr}, #endif #ifdef DROPBEAR_3DES {"3des-cbc", 0, &dropbear_3des, 1, &dropbear_mode_cbc}, #endif #ifdef DROPBEAR_BLOWFISH {"blowfish-cbc", 0, &dropbear_blowfish, 1, &dropbear_mode_cbc}, #endif #endif /* DROPBEAR_ENABLE_CBC_MODE */ #ifdef DROPBEAR_NONE_CIPHER {"none", 0, (void*)&dropbear_nocipher, 1, &dropbear_mode_none}, #endif {NULL, 0, NULL, 0, NULL} }; algo_type sshhashes[] = { #ifdef DROPBEAR_SHA1_96_HMAC {"hmac-sha1-96", 0, &dropbear_sha1_96, 1, NULL}, #endif #ifdef DROPBEAR_SHA1_HMAC {"hmac-sha1", 0, &dropbear_sha1, 1, NULL}, #endif #ifdef DROPBEAR_SHA2_256_HMAC {"hmac-sha2-256", 0, &dropbear_sha2_256, 1, NULL}, #endif #ifdef DROPBEAR_SHA2_512_HMAC {"hmac-sha2-512", 0, &dropbear_sha2_512, 1, NULL}, #endif #ifdef DROPBEAR_MD5_HMAC {"hmac-md5", 0, (void*)&dropbear_md5, 1, NULL}, #endif #ifdef DROPBEAR_NONE_INTEGRITY {"none", 0, (void*)&dropbear_nohash, 1, NULL}, #endif {NULL, 0, NULL, 0, NULL} }; #ifndef DISABLE_ZLIB algo_type ssh_compress[] = { {"[email protected]", DROPBEAR_COMP_ZLIB_DELAY, NULL, 1, NULL}, {"zlib", DROPBEAR_COMP_ZLIB, NULL, 1, NULL}, {"none", DROPBEAR_COMP_NONE, NULL, 1, NULL}, {NULL, 0, NULL, 0, NULL} }; algo_type ssh_delaycompress[] = { {"[email protected]", DROPBEAR_COMP_ZLIB_DELAY, NULL, 1, NULL}, {"none", DROPBEAR_COMP_NONE, NULL, 1, NULL}, {NULL, 0, NULL, 0, NULL} }; #endif algo_type ssh_nocompress[] = { {"none", DROPBEAR_COMP_NONE, NULL, 1, NULL}, {NULL, 0, NULL, 0, NULL} }; algo_type sshhostkey[] = { #ifdef DROPBEAR_ECDSA #ifdef DROPBEAR_ECC_256 {"ecdsa-sha2-nistp256", DROPBEAR_SIGNKEY_ECDSA_NISTP256, NULL, 1, NULL}, #endif #ifdef DROPBEAR_ECC_384 {"ecdsa-sha2-nistp384", DROPBEAR_SIGNKEY_ECDSA_NISTP384, NULL, 1, NULL}, #endif #ifdef DROPBEAR_ECC_521 {"ecdsa-sha2-nistp521", DROPBEAR_SIGNKEY_ECDSA_NISTP521, NULL, 1, NULL}, #endif #endif #ifdef DROPBEAR_RSA {"ssh-rsa", DROPBEAR_SIGNKEY_RSA, NULL, 1, NULL}, #endif #ifdef DROPBEAR_DSS {"ssh-dss", DROPBEAR_SIGNKEY_DSS, NULL, 1, NULL}, #endif {NULL, 0, NULL, 0, NULL} }; #if DROPBEAR_DH_GROUP1 static const struct dropbear_kex kex_dh_group1 = {DROPBEAR_KEX_NORMAL_DH, dh_p_1, DH_P_1_LEN, NULL, &sha1_desc }; #endif #if DROPBEAR_DH_GROUP14 static const struct dropbear_kex kex_dh_group14_sha1 = {DROPBEAR_KEX_NORMAL_DH, dh_p_14, DH_P_14_LEN, NULL, &sha1_desc }; #if DROPBEAR_DH_GROUP14_256 static const struct dropbear_kex kex_dh_group14_sha256 = {DROPBEAR_KEX_NORMAL_DH, dh_p_14, DH_P_14_LEN, NULL, &sha256_desc }; #endif #endif #if DROPBEAR_DH_GROUP16 static const struct dropbear_kex kex_dh_group16_sha512 = {DROPBEAR_KEX_NORMAL_DH, dh_p_16, DH_P_16_LEN, NULL, &sha512_desc }; #endif /* These can't be const since dropbear_ecc_fill_dp() fills out ecc_curve at runtime */ #ifdef DROPBEAR_ECDH #ifdef DROPBEAR_ECC_256 static const struct dropbear_kex kex_ecdh_nistp256 = {DROPBEAR_KEX_ECDH, NULL, 0, &ecc_curve_nistp256, &sha256_desc }; #endif #ifdef DROPBEAR_ECC_384 static const struct dropbear_kex kex_ecdh_nistp384 = {DROPBEAR_KEX_ECDH, NULL, 0, &ecc_curve_nistp384, &sha384_desc }; #endif #ifdef DROPBEAR_ECC_521 static const struct dropbear_kex kex_ecdh_nistp521 = {DROPBEAR_KEX_ECDH, NULL, 0, &ecc_curve_nistp521, &sha512_desc }; #endif #endif /* DROPBEAR_ECDH */ #ifdef DROPBEAR_CURVE25519 /* Referred to directly */ static const struct dropbear_kex kex_curve25519 = {DROPBEAR_KEX_CURVE25519, NULL, 0, NULL, &sha256_desc }; #endif algo_type sshkex[] = { #ifdef DROPBEAR_CURVE25519 {"[email protected]", 0, &kex_curve25519, 1, NULL}, #endif #ifdef DROPBEAR_ECDH #ifdef DROPBEAR_ECC_521 {"ecdh-sha2-nistp521", 0, &kex_ecdh_nistp521, 1, NULL}, #endif #ifdef DROPBEAR_ECC_384 {"ecdh-sha2-nistp384", 0, &kex_ecdh_nistp384, 1, NULL}, #endif #ifdef DROPBEAR_ECC_256 {"ecdh-sha2-nistp256", 0, &kex_ecdh_nistp256, 1, NULL}, #endif #endif #if DROPBEAR_DH_GROUP14 #if DROPBEAR_DH_GROUP14_256 {"diffie-hellman-group14-sha256", 0, &kex_dh_group14_sha256, 1, NULL}, #endif {"diffie-hellman-group14-sha1", 0, &kex_dh_group14_sha1, 1, NULL}, #endif #if DROPBEAR_DH_GROUP1 {"diffie-hellman-group1-sha1", 0, &kex_dh_group1, 1, NULL}, #endif #if DROPBEAR_DH_GROUP16 {"diffie-hellman-group16-sha512", 0, &kex_dh_group16_sha512, 1, NULL}, #endif #ifdef USE_KEXGUESS2 {KEXGUESS2_ALGO_NAME, KEXGUESS2_ALGO_ID, NULL, 1, NULL}, #endif {NULL, 0, NULL, 0, NULL} }; /* algolen specifies the length of algo, algos is our local list to match * against. * Returns DROPBEAR_SUCCESS if we have a match for algo, DROPBEAR_FAILURE * otherwise */ int have_algo(char* algo, size_t algolen, algo_type algos[]) { int i; for (i = 0; algos[i].name != NULL; i++) { if (strlen(algos[i].name) == algolen && (strncmp(algos[i].name, algo, algolen) == 0)) { return DROPBEAR_SUCCESS; } } return DROPBEAR_FAILURE; } /* Output a comma separated list of algorithms to a buffer */ void buf_put_algolist(buffer * buf, algo_type localalgos[]) { unsigned int i, len; unsigned int donefirst = 0; buffer *algolist = NULL; algolist = buf_new(300); for (i = 0; localalgos[i].name != NULL; i++) { if (localalgos[i].usable) { if (donefirst) buf_putbyte(algolist, ','); donefirst = 1; len = strlen(localalgos[i].name); buf_putbytes(algolist, (const unsigned char *) localalgos[i].name, len); } } buf_putstring(buf, (const char*)algolist->data, algolist->len); buf_free(algolist); } /* match the first algorithm in the comma-separated list in buf which is * also in localalgos[], or return NULL on failure. * (*goodguess) is set to 1 if the preferred client/server algos match, * 0 otherwise. This is used for checking if the kexalgo/hostkeyalgos are * guessed correctly */ algo_type * buf_match_algo(buffer* buf, algo_type localalgos[], enum kexguess2_used *kexguess2, int *goodguess) { char * algolist = NULL; const char *remotenames[MAX_PROPOSED_ALGO], *localnames[MAX_PROPOSED_ALGO]; unsigned int len; unsigned int remotecount, localcount, clicount, servcount, i, j; algo_type * ret = NULL; const char **clinames, **servnames; if (goodguess) { *goodguess = 0; } /* get the comma-separated list from the buffer ie "algo1,algo2,algo3" */ algolist = buf_getstring(buf, &len); TRACE(("buf_match_algo: %s", algolist)) if (len > MAX_PROPOSED_ALGO*(MAX_NAME_LEN+1)) { goto out; } /* remotenames will contain a list of the strings parsed out */ /* We will have at least one string (even if it's just "") */ remotenames[0] = algolist; remotecount = 1; for (i = 0; i < len; i++) { if (algolist[i] == '\0') { /* someone is trying something strange */ goto out; } if (algolist[i] == ',') { algolist[i] = '\0'; remotenames[remotecount] = &algolist[i+1]; remotecount++; } if (remotecount >= MAX_PROPOSED_ALGO) { break; } } if (kexguess2 && *kexguess2 == KEXGUESS2_LOOK) { for (i = 0; i < remotecount; i++) { if (strcmp(remotenames[i], KEXGUESS2_ALGO_NAME) == 0) { *kexguess2 = KEXGUESS2_YES; break; } } if (*kexguess2 == KEXGUESS2_LOOK) { *kexguess2 = KEXGUESS2_NO; } } for (i = 0; localalgos[i].name != NULL; i++) { if (localalgos[i].usable) { localnames[i] = localalgos[i].name; } else { localnames[i] = NULL; } } localcount = i; if (IS_DROPBEAR_SERVER) { clinames = remotenames; clicount = remotecount; servnames = localnames; servcount = localcount; } else { clinames = localnames; clicount = localcount; servnames = remotenames; servcount = remotecount; } /* iterate and find the first match */ for (i = 0; i < clicount; i++) { for (j = 0; j < servcount; j++) { if (!(servnames[j] && clinames[i])) { /* unusable algos are NULL */ continue; } if (strcmp(servnames[j], clinames[i]) == 0) { /* set if it was a good guess */ if (goodguess && kexguess2) { if (*kexguess2 == KEXGUESS2_YES) { if (i == 0) { *goodguess = 1; } } else { if (i == 0 && j == 0) { *goodguess = 1; } } } /* set the algo to return */ if (IS_DROPBEAR_SERVER) { ret = &localalgos[j]; } else { ret = &localalgos[i]; } goto out; } } } out: m_free(algolist); return ret; } #ifdef DROPBEAR_NONE_CIPHER void set_algo_usable(algo_type algos[], const char * algo_name, int usable) { algo_type *a; for (a = algos; a->name != NULL; a++) { if (strcmp(a->name, algo_name) == 0) { a->usable = usable; return; } } } int get_algo_usable(algo_type algos[], const char * algo_name) { algo_type *a; for (a = algos; a->name != NULL; a++) { if (strcmp(a->name, algo_name) == 0) { return a->usable; } } return 0; } #endif /* DROPBEAR_NONE_CIPHER */ #ifdef ENABLE_USER_ALGO_LIST char * algolist_string(algo_type algos[]) { char *ret_list; buffer *b = buf_new(200); buf_put_algolist(b, algos); buf_setpos(b, b->len); buf_putbyte(b, '\0'); buf_setpos(b, 4); ret_list = m_strdup((const char *) buf_getptr(b, b->len - b->pos)); buf_free(b); return ret_list; } static algo_type* check_algo(const char* algo_name, algo_type *algos) { algo_type *a; for (a = algos; a->name != NULL; a++) { if (strcmp(a->name, algo_name) == 0) { return a; } } return NULL; } /* Checks a user provided comma-separated algorithm list for available * options. Any that are not acceptable are removed in-place. Returns the * number of valid algorithms. */ int check_user_algos(const char* user_algo_list, algo_type * algos, const char *algo_desc) { algo_type new_algos[MAX_PROPOSED_ALGO+1]; char *work_list = m_strdup(user_algo_list); char *start = work_list; char *c; int n; /* So we can iterate and look for null terminator */ memset(new_algos, 0x0, sizeof(new_algos)); for (c = work_list, n = 0; ; c++) { char oc = *c; if (n >= MAX_PROPOSED_ALGO) { dropbear_exit("Too many algorithms '%s'", user_algo_list); } if (*c == ',' || *c == '\0') { algo_type *match_algo = NULL; *c = '\0'; match_algo = check_algo(start, algos); if (match_algo) { if (check_algo(start, new_algos)) { TRACE(("Skip repeated algorithm '%s'", start)) } else { new_algos[n] = *match_algo; n++; } } else { dropbear_log(LOG_WARNING, "This Dropbear program does not support '%s' %s algorithm", start, algo_desc); } c++; start = c; } if (oc == '\0') { break; } } m_free(work_list); /* n+1 to include a null terminator */ memcpy(algos, new_algos, sizeof(*new_algos) * (n+1)); return n; } #endif /* ENABLE_USER_ALGO_LIST */