diff options
author | markus@openbsd.org <markus@openbsd.org> | 2015-01-19 20:16:15 +0000 |
---|---|---|
committer | Damien Miller <djm@mindrot.org> | 2015-01-20 09:19:39 +1100 |
commit | 57d10cbe861a235dd269c74fb2fe248469ecee9d (patch) | |
tree | c65deed24700490bd3b20300c4829d4d5466ff6d /kexdhc.c | |
parent | 3fdc88a0def4f86aa88a5846ac079dc964c0546a (diff) |
upstream commit
adapt kex to sshbuf and struct ssh; ok djm@
Diffstat (limited to 'kexdhc.c')
-rw-r--r-- | kexdhc.c | 194 |
1 files changed, 120 insertions, 74 deletions
@@ -1,4 +1,4 @@ -/* $OpenBSD: kexdhc.c,v 1.16 2015/01/19 19:52:16 markus Exp $ */ +/* $OpenBSD: kexdhc.c,v 1.17 2015/01/19 20:16:15 markus Exp $ */ /* * Copyright (c) 2001 Markus Friedl. All rights reserved. * @@ -36,129 +36,175 @@ #include <string.h> #include <signal.h> -#include "xmalloc.h" -#include "buffer.h" -#include "key.h" +#include "sshkey.h" #include "cipher.h" +#include "digest.h" #include "kex.h" #include "log.h" #include "packet.h" #include "dh.h" #include "ssh2.h" +#include "dispatch.h" +#include "compat.h" +#include "ssherr.h" +#include "sshbuf.h" -void -kexdh_client(Kex *kex) +static int input_kex_dh(int, u_int32_t, void *); + +int +kexdh_client(struct ssh *ssh) { - BIGNUM *dh_server_pub = NULL, *shared_secret = NULL; - DH *dh; - Key *server_host_key; - u_char *server_host_key_blob = NULL, *signature = NULL; - u_char *kbuf, *hash; - u_int klen, slen, sbloblen, hashlen; - int kout; + struct kex *kex = ssh->kex; + int r; /* generate and send 'e', client DH public key */ switch (kex->kex_type) { case KEX_DH_GRP1_SHA1: - dh = dh_new_group1(); + kex->dh = dh_new_group1(); break; case KEX_DH_GRP14_SHA1: - dh = dh_new_group14(); + kex->dh = dh_new_group14(); break; default: - fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type); + r = SSH_ERR_INVALID_ARGUMENT; + goto out; + } + if (kex->dh == NULL) { + r = SSH_ERR_ALLOC_FAIL; + goto out; } - dh_gen_key(dh, kex->we_need * 8); - packet_start(SSH2_MSG_KEXDH_INIT); - packet_put_bignum2(dh->pub_key); - packet_send(); - debug("sending SSH2_MSG_KEXDH_INIT"); + if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0 || + (r = sshpkt_start(ssh, SSH2_MSG_KEXDH_INIT)) != 0 || + (r = sshpkt_put_bignum2(ssh, kex->dh->pub_key)) != 0 || + (r = sshpkt_send(ssh)) != 0) + goto out; #ifdef DEBUG_KEXDH - DHparams_print_fp(stderr, dh); + DHparams_print_fp(stderr, kex->dh); fprintf(stderr, "pub= "); - BN_print_fp(stderr, dh->pub_key); + BN_print_fp(stderr, kex->dh->pub_key); fprintf(stderr, "\n"); #endif - debug("expecting SSH2_MSG_KEXDH_REPLY"); - packet_read_expect(SSH2_MSG_KEXDH_REPLY); + ssh_dispatch_set(ssh, SSH2_MSG_KEXDH_REPLY, &input_kex_dh); + r = 0; + out: + return r; +} +static int +input_kex_dh(int type, u_int32_t seq, void *ctxt) +{ + struct ssh *ssh = ctxt; + struct kex *kex = ssh->kex; + BIGNUM *dh_server_pub = NULL, *shared_secret = NULL; + struct sshkey *server_host_key = NULL; + u_char *kbuf = NULL, *server_host_key_blob = NULL, *signature = NULL; + u_char hash[SSH_DIGEST_MAX_LENGTH]; + size_t klen = 0, slen, sbloblen, hashlen; + int kout, r; + + if (kex->verify_host_key == NULL) { + r = SSH_ERR_INVALID_ARGUMENT; + goto out; + } /* key, cert */ - server_host_key_blob = packet_get_string(&sbloblen); - server_host_key = key_from_blob(server_host_key_blob, sbloblen); - if (server_host_key == NULL) - fatal("cannot decode server_host_key_blob"); - if (server_host_key->type != kex->hostkey_type) - fatal("type mismatch for decoded server_host_key_blob"); - if (kex->verify_host_key == NULL) - fatal("cannot verify server_host_key"); - if (kex->verify_host_key(server_host_key) == -1) - fatal("server_host_key verification failed"); - + if ((r = sshpkt_get_string(ssh, &server_host_key_blob, + &sbloblen)) != 0 || + (r = sshkey_from_blob(server_host_key_blob, sbloblen, + &server_host_key)) != 0) + goto out; + if (server_host_key->type != kex->hostkey_type) { + r = SSH_ERR_KEY_TYPE_MISMATCH; + goto out; + } + if (kex->verify_host_key(server_host_key, ssh) == -1) { + r = SSH_ERR_SIGNATURE_INVALID; + goto out; + } /* DH parameter f, server public DH key */ - if ((dh_server_pub = BN_new()) == NULL) - fatal("dh_server_pub == NULL"); - packet_get_bignum2(dh_server_pub); - + if ((dh_server_pub = BN_new()) == NULL) { + r = SSH_ERR_ALLOC_FAIL; + goto out; + } + /* signed H */ + if ((r = sshpkt_get_bignum2(ssh, dh_server_pub)) != 0 || + (r = sshpkt_get_string(ssh, &signature, &slen)) != 0 || + (r = sshpkt_get_end(ssh)) != 0) + goto out; #ifdef DEBUG_KEXDH fprintf(stderr, "dh_server_pub= "); BN_print_fp(stderr, dh_server_pub); fprintf(stderr, "\n"); debug("bits %d", BN_num_bits(dh_server_pub)); #endif + if (!dh_pub_is_valid(kex->dh, dh_server_pub)) { + sshpkt_disconnect(ssh, "bad server public DH value"); + r = SSH_ERR_MESSAGE_INCOMPLETE; + goto out; + } - /* signed H */ - signature = packet_get_string(&slen); - packet_check_eom(); - - if (!dh_pub_is_valid(dh, dh_server_pub)) - packet_disconnect("bad server public DH value"); - - klen = DH_size(dh); - kbuf = xmalloc(klen); - if ((kout = DH_compute_key(kbuf, dh_server_pub, dh)) < 0) - fatal("DH_compute_key: failed"); + klen = DH_size(kex->dh); + if ((kbuf = malloc(klen)) == NULL || + (shared_secret = BN_new()) == NULL) { + r = SSH_ERR_ALLOC_FAIL; + goto out; + } + if ((kout = DH_compute_key(kbuf, dh_server_pub, kex->dh)) < 0 || + BN_bin2bn(kbuf, kout, shared_secret) == NULL) { + r = SSH_ERR_LIBCRYPTO_ERROR; + goto out; + } #ifdef DEBUG_KEXDH dump_digest("shared secret", kbuf, kout); #endif - if ((shared_secret = BN_new()) == NULL) - fatal("kexdh_client: BN_new failed"); - if (BN_bin2bn(kbuf, kout, shared_secret) == NULL) - fatal("kexdh_client: BN_bin2bn failed"); - explicit_bzero(kbuf, klen); - free(kbuf); /* calc and verify H */ - kex_dh_hash( + hashlen = sizeof(hash); + if ((r = kex_dh_hash( kex->client_version_string, kex->server_version_string, - buffer_ptr(kex->my), buffer_len(kex->my), - buffer_ptr(kex->peer), buffer_len(kex->peer), + sshbuf_ptr(kex->my), sshbuf_len(kex->my), + sshbuf_ptr(kex->peer), sshbuf_len(kex->peer), server_host_key_blob, sbloblen, - dh->pub_key, + kex->dh->pub_key, dh_server_pub, shared_secret, - &hash, &hashlen - ); - free(server_host_key_blob); - BN_clear_free(dh_server_pub); - DH_free(dh); + hash, &hashlen)) != 0) + goto out; - if (key_verify(server_host_key, signature, slen, hash, hashlen) != 1) - fatal("key_verify failed for server_host_key"); - key_free(server_host_key); - free(signature); + if ((r = sshkey_verify(server_host_key, signature, slen, hash, hashlen, + ssh->compat)) != 0) + goto out; /* save session id */ if (kex->session_id == NULL) { kex->session_id_len = hashlen; - kex->session_id = xmalloc(kex->session_id_len); + kex->session_id = malloc(kex->session_id_len); + if (kex->session_id == NULL) { + r = SSH_ERR_ALLOC_FAIL; + goto out; + } memcpy(kex->session_id, hash, kex->session_id_len); } - kex_derive_keys_bn(kex, hash, hashlen, shared_secret); - BN_clear_free(shared_secret); - kex_finish(kex); + if ((r = kex_derive_keys_bn(ssh, hash, hashlen, shared_secret)) == 0) + r = kex_send_newkeys(ssh); + out: + explicit_bzero(hash, sizeof(hash)); + DH_free(kex->dh); + kex->dh = NULL; + if (dh_server_pub) + BN_clear_free(dh_server_pub); + if (kbuf) { + explicit_bzero(kbuf, klen); + free(kbuf); + } + if (shared_secret) + BN_clear_free(shared_secret); + sshkey_free(server_host_key); + free(server_host_key_blob); + free(signature); + return r; } #endif /* WITH_OPENSSL */ |