version 1.19, 2015/01/19 19:52:16 |
version 1.20, 2015/01/19 20:16:15 |
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#include <openssl/dh.h> |
#include <openssl/dh.h> |
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#include "xmalloc.h" |
#include "sshkey.h" |
#include "buffer.h" |
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#include "key.h" |
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#include "cipher.h" |
#include "cipher.h" |
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#include "digest.h" |
#include "kex.h" |
#include "kex.h" |
#include "log.h" |
#include "log.h" |
#include "packet.h" |
#include "packet.h" |
#include "dh.h" |
#include "dh.h" |
#include "ssh2.h" |
#include "ssh2.h" |
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void |
#include "dispatch.h" |
kexdh_server(Kex *kex) |
#include "compat.h" |
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#include "ssherr.h" |
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#include "sshbuf.h" |
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static int input_kex_dh_init(int, u_int32_t, void *); |
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int |
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kexdh_server(struct ssh *ssh) |
{ |
{ |
BIGNUM *shared_secret = NULL, *dh_client_pub = NULL; |
struct kex *kex = ssh->kex; |
DH *dh; |
int r; |
Key *server_host_public, *server_host_private; |
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u_char *kbuf, *hash, *signature = NULL, *server_host_key_blob = NULL; |
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u_int sbloblen, klen, hashlen, slen; |
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int kout; |
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/* generate server DH public key */ |
/* generate server DH public key */ |
switch (kex->kex_type) { |
switch (kex->kex_type) { |
case KEX_DH_GRP1_SHA1: |
case KEX_DH_GRP1_SHA1: |
dh = dh_new_group1(); |
kex->dh = dh_new_group1(); |
break; |
break; |
case KEX_DH_GRP14_SHA1: |
case KEX_DH_GRP14_SHA1: |
dh = dh_new_group14(); |
kex->dh = dh_new_group14(); |
break; |
break; |
default: |
default: |
fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type); |
r = SSH_ERR_INVALID_ARGUMENT; |
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goto out; |
} |
} |
dh_gen_key(dh, kex->we_need * 8); |
if (kex->dh == NULL) { |
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r = SSH_ERR_ALLOC_FAIL; |
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goto out; |
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} |
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if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0) |
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goto out; |
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debug("expecting SSH2_MSG_KEXDH_INIT"); |
debug("expecting SSH2_MSG_KEXDH_INIT"); |
packet_read_expect(SSH2_MSG_KEXDH_INIT); |
ssh_dispatch_set(ssh, SSH2_MSG_KEXDH_INIT, &input_kex_dh_init); |
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r = 0; |
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out: |
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return r; |
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} |
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int |
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input_kex_dh_init(int type, u_int32_t seq, void *ctxt) |
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{ |
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struct ssh *ssh = ctxt; |
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struct kex *kex = ssh->kex; |
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BIGNUM *shared_secret = NULL, *dh_client_pub = NULL; |
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struct sshkey *server_host_public, *server_host_private; |
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u_char *kbuf = NULL, *signature = NULL, *server_host_key_blob = NULL; |
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u_char hash[SSH_DIGEST_MAX_LENGTH]; |
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size_t sbloblen, slen; |
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size_t klen = 0, hashlen; |
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int kout, r; |
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if (kex->load_host_public_key == NULL || |
if (kex->load_host_public_key == NULL || |
kex->load_host_private_key == NULL) |
kex->load_host_private_key == NULL) { |
fatal("Cannot load hostkey"); |
r = SSH_ERR_INVALID_ARGUMENT; |
server_host_public = kex->load_host_public_key(kex->hostkey_type); |
goto out; |
if (server_host_public == NULL) |
} |
fatal("Unsupported hostkey type %d", kex->hostkey_type); |
if ((server_host_public = kex->load_host_public_key(kex->hostkey_type, |
server_host_private = kex->load_host_private_key(kex->hostkey_type); |
ssh)) == NULL || |
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(server_host_private = kex->load_host_private_key(kex->hostkey_type, |
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ssh)) == NULL) { |
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r = SSH_ERR_NO_HOSTKEY_LOADED; |
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goto out; |
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} |
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/* key, cert */ |
/* key, cert */ |
if ((dh_client_pub = BN_new()) == NULL) |
if ((dh_client_pub = BN_new()) == NULL) { |
fatal("dh_client_pub == NULL"); |
r = SSH_ERR_ALLOC_FAIL; |
packet_get_bignum2(dh_client_pub); |
goto out; |
packet_check_eom(); |
} |
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if ((r = sshpkt_get_bignum2(ssh, dh_client_pub)) != 0 || |
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(r = sshpkt_get_end(ssh)) != 0) |
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goto out; |
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#ifdef DEBUG_KEXDH |
#ifdef DEBUG_KEXDH |
fprintf(stderr, "dh_client_pub= "); |
fprintf(stderr, "dh_client_pub= "); |
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#endif |
#endif |
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#ifdef DEBUG_KEXDH |
#ifdef DEBUG_KEXDH |
DHparams_print_fp(stderr, dh); |
DHparams_print_fp(stderr, kex->dh); |
fprintf(stderr, "pub= "); |
fprintf(stderr, "pub= "); |
BN_print_fp(stderr, dh->pub_key); |
BN_print_fp(stderr, kex->dh->pub_key); |
fprintf(stderr, "\n"); |
fprintf(stderr, "\n"); |
#endif |
#endif |
if (!dh_pub_is_valid(dh, dh_client_pub)) |
if (!dh_pub_is_valid(kex->dh, dh_client_pub)) { |
packet_disconnect("bad client public DH value"); |
sshpkt_disconnect(ssh, "bad client public DH value"); |
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r = SSH_ERR_MESSAGE_INCOMPLETE; |
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goto out; |
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} |
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klen = DH_size(dh); |
klen = DH_size(kex->dh); |
kbuf = xmalloc(klen); |
if ((kbuf = malloc(klen)) == NULL || |
if ((kout = DH_compute_key(kbuf, dh_client_pub, dh)) < 0) |
(shared_secret = BN_new()) == NULL) { |
fatal("DH_compute_key: failed"); |
r = SSH_ERR_ALLOC_FAIL; |
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goto out; |
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} |
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if ((kout = DH_compute_key(kbuf, dh_client_pub, kex->dh)) < 0 || |
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BN_bin2bn(kbuf, kout, shared_secret) == NULL) { |
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r = SSH_ERR_LIBCRYPTO_ERROR; |
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goto out; |
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} |
#ifdef DEBUG_KEXDH |
#ifdef DEBUG_KEXDH |
dump_digest("shared secret", kbuf, kout); |
dump_digest("shared secret", kbuf, kout); |
#endif |
#endif |
if ((shared_secret = BN_new()) == NULL) |
if ((r = sshkey_to_blob(server_host_public, &server_host_key_blob, |
fatal("kexdh_server: BN_new failed"); |
&sbloblen)) != 0) |
if (BN_bin2bn(kbuf, kout, shared_secret) == NULL) |
goto out; |
fatal("kexdh_server: BN_bin2bn failed"); |
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explicit_bzero(kbuf, klen); |
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free(kbuf); |
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key_to_blob(server_host_public, &server_host_key_blob, &sbloblen); |
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/* calc H */ |
/* calc H */ |
kex_dh_hash( |
hashlen = sizeof(hash); |
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if ((r = kex_dh_hash( |
kex->client_version_string, |
kex->client_version_string, |
kex->server_version_string, |
kex->server_version_string, |
buffer_ptr(kex->peer), buffer_len(kex->peer), |
sshbuf_ptr(kex->peer), sshbuf_len(kex->peer), |
buffer_ptr(kex->my), buffer_len(kex->my), |
sshbuf_ptr(kex->my), sshbuf_len(kex->my), |
server_host_key_blob, sbloblen, |
server_host_key_blob, sbloblen, |
dh_client_pub, |
dh_client_pub, |
dh->pub_key, |
kex->dh->pub_key, |
shared_secret, |
shared_secret, |
&hash, &hashlen |
hash, &hashlen)) != 0) |
); |
goto out; |
BN_clear_free(dh_client_pub); |
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/* save session id := H */ |
/* save session id := H */ |
if (kex->session_id == NULL) { |
if (kex->session_id == NULL) { |
kex->session_id_len = hashlen; |
kex->session_id_len = hashlen; |
kex->session_id = xmalloc(kex->session_id_len); |
kex->session_id = malloc(kex->session_id_len); |
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if (kex->session_id == NULL) { |
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r = SSH_ERR_ALLOC_FAIL; |
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goto out; |
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} |
memcpy(kex->session_id, hash, kex->session_id_len); |
memcpy(kex->session_id, hash, kex->session_id_len); |
} |
} |
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/* sign H */ |
/* sign H */ |
kex->sign(server_host_private, server_host_public, &signature, &slen, |
if ((r = kex->sign(server_host_private, server_host_public, |
hash, hashlen); |
&signature, &slen, hash, hashlen, ssh->compat)) < 0) |
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goto out; |
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/* destroy_sensitive_data(); */ |
/* destroy_sensitive_data(); */ |
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/* send server hostkey, DH pubkey 'f' and singed H */ |
/* send server hostkey, DH pubkey 'f' and singed H */ |
packet_start(SSH2_MSG_KEXDH_REPLY); |
if ((r = sshpkt_start(ssh, SSH2_MSG_KEXDH_REPLY)) != 0 || |
packet_put_string(server_host_key_blob, sbloblen); |
(r = sshpkt_put_string(ssh, server_host_key_blob, sbloblen)) != 0 || |
packet_put_bignum2(dh->pub_key); /* f */ |
(r = sshpkt_put_bignum2(ssh, kex->dh->pub_key)) != 0 || /* f */ |
packet_put_string(signature, slen); |
(r = sshpkt_put_string(ssh, signature, slen)) != 0 || |
packet_send(); |
(r = sshpkt_send(ssh)) != 0) |
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goto out; |
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free(signature); |
if ((r = kex_derive_keys_bn(ssh, hash, hashlen, shared_secret)) == 0) |
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r = kex_send_newkeys(ssh); |
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out: |
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explicit_bzero(hash, sizeof(hash)); |
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DH_free(kex->dh); |
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kex->dh = NULL; |
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if (dh_client_pub) |
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BN_clear_free(dh_client_pub); |
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if (kbuf) { |
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explicit_bzero(kbuf, klen); |
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free(kbuf); |
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} |
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if (shared_secret) |
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BN_clear_free(shared_secret); |
free(server_host_key_blob); |
free(server_host_key_blob); |
/* have keys, free DH */ |
free(signature); |
DH_free(dh); |
return r; |
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kex_derive_keys_bn(kex, hash, hashlen, shared_secret); |
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BN_clear_free(shared_secret); |
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kex_finish(kex); |
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} |
} |