version 1.20, 2015/01/19 19:52:16 |
version 1.21, 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" |
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#include "ssh-gss.h" |
#include "ssh-gss.h" |
#endif |
#endif |
#include "monitor_wrap.h" |
#include "monitor_wrap.h" |
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#include "dispatch.h" |
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#include "ssherr.h" |
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#include "sshbuf.h" |
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void |
static int input_kex_dh_gex_request(int, u_int32_t, void *); |
kexgex_server(Kex *kex) |
static int input_kex_dh_gex_init(int, u_int32_t, void *); |
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int |
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kexgex_server(struct ssh *ssh) |
{ |
{ |
BIGNUM *shared_secret = NULL, *dh_client_pub = NULL; |
ssh_dispatch_set(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST_OLD, |
Key *server_host_public, *server_host_private; |
&input_kex_dh_gex_request); |
DH *dh; |
ssh_dispatch_set(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST, |
u_char *kbuf, *hash, *signature = NULL, *server_host_key_blob = NULL; |
&input_kex_dh_gex_request); |
u_int sbloblen, klen, slen, hashlen; |
debug("expecting SSH2_MSG_KEX_DH_GEX_REQUEST"); |
int omin = -1, min = -1, omax = -1, max = -1, onbits = -1, nbits = -1; |
return 0; |
int type, kout; |
} |
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if (kex->load_host_public_key == NULL || |
static int |
kex->load_host_private_key == NULL) |
input_kex_dh_gex_request(int type, u_int32_t seq, void *ctxt) |
fatal("Cannot load hostkey"); |
{ |
server_host_public = kex->load_host_public_key(kex->hostkey_type); |
struct ssh *ssh = ctxt; |
if (server_host_public == NULL) |
struct kex *kex = ssh->kex; |
fatal("Unsupported hostkey type %d", kex->hostkey_type); |
int r; |
server_host_private = kex->load_host_private_key(kex->hostkey_type); |
u_int min = 0, max = 0, nbits = 0; |
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type = packet_read(); |
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switch (type) { |
switch (type) { |
case SSH2_MSG_KEX_DH_GEX_REQUEST: |
case SSH2_MSG_KEX_DH_GEX_REQUEST: |
debug("SSH2_MSG_KEX_DH_GEX_REQUEST received"); |
debug("SSH2_MSG_KEX_DH_GEX_REQUEST received"); |
omin = min = packet_get_int(); |
if ((r = sshpkt_get_u32(ssh, &min)) != 0 || |
onbits = nbits = packet_get_int(); |
(r = sshpkt_get_u32(ssh, &nbits)) != 0 || |
omax = max = packet_get_int(); |
(r = sshpkt_get_u32(ssh, &max)) != 0 || |
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(r = sshpkt_get_end(ssh)) != 0) |
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goto out; |
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kex->nbits = nbits; |
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kex->min = min; |
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kex->max = max; |
min = MAX(DH_GRP_MIN, min); |
min = MAX(DH_GRP_MIN, min); |
max = MIN(DH_GRP_MAX, max); |
max = MIN(DH_GRP_MAX, max); |
nbits = MAX(DH_GRP_MIN, nbits); |
nbits = MAX(DH_GRP_MIN, nbits); |
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break; |
break; |
case SSH2_MSG_KEX_DH_GEX_REQUEST_OLD: |
case SSH2_MSG_KEX_DH_GEX_REQUEST_OLD: |
debug("SSH2_MSG_KEX_DH_GEX_REQUEST_OLD received"); |
debug("SSH2_MSG_KEX_DH_GEX_REQUEST_OLD received"); |
onbits = nbits = packet_get_int(); |
if ((r = sshpkt_get_u32(ssh, &nbits)) != 0 || |
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(r = sshpkt_get_end(ssh)) != 0) |
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goto out; |
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kex->nbits = nbits; |
/* unused for old GEX */ |
/* unused for old GEX */ |
omin = min = DH_GRP_MIN; |
kex->min = min = DH_GRP_MIN; |
omax = max = DH_GRP_MAX; |
kex->max = max = DH_GRP_MAX; |
break; |
break; |
default: |
default: |
fatal("protocol error during kex, no DH_GEX_REQUEST: %d", type); |
r = SSH_ERR_INVALID_ARGUMENT; |
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goto out; |
} |
} |
packet_check_eom(); |
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if (omax < omin || onbits < omin || omax < onbits) |
if (kex->max < kex->min || kex->nbits < kex->min || |
fatal("DH_GEX_REQUEST, bad parameters: %d !< %d !< %d", |
kex->max < kex->nbits) { |
omin, onbits, omax); |
r = SSH_ERR_DH_GEX_OUT_OF_RANGE; |
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goto out; |
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} |
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/* Contact privileged parent */ |
/* Contact privileged parent */ |
dh = PRIVSEP(choose_dh(min, nbits, max)); |
kex->dh = PRIVSEP(choose_dh(min, nbits, max)); |
if (dh == NULL) |
if (kex->dh == NULL) { |
packet_disconnect("Protocol error: no matching DH grp found"); |
sshpkt_disconnect(ssh, "no matching DH grp found"); |
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r = SSH_ERR_ALLOC_FAIL; |
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goto out; |
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} |
debug("SSH2_MSG_KEX_DH_GEX_GROUP sent"); |
debug("SSH2_MSG_KEX_DH_GEX_GROUP sent"); |
packet_start(SSH2_MSG_KEX_DH_GEX_GROUP); |
if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_DH_GEX_GROUP)) != 0 || |
packet_put_bignum2(dh->p); |
(r = sshpkt_put_bignum2(ssh, kex->dh->p)) != 0 || |
packet_put_bignum2(dh->g); |
(r = sshpkt_put_bignum2(ssh, kex->dh->g)) != 0 || |
packet_send(); |
(r = sshpkt_send(ssh)) != 0) |
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goto out; |
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/* flush */ |
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packet_write_wait(); |
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/* Compute our exchange value in parallel with the client */ |
/* Compute our exchange value in parallel with the client */ |
dh_gen_key(dh, kex->we_need * 8); |
if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0) |
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goto out; |
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/* old KEX does not use min/max in kexgex_hash() */ |
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if (type == SSH2_MSG_KEX_DH_GEX_REQUEST_OLD) |
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kex->min = kex->max = -1; |
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debug("expecting SSH2_MSG_KEX_DH_GEX_INIT"); |
debug("expecting SSH2_MSG_KEX_DH_GEX_INIT"); |
packet_read_expect(SSH2_MSG_KEX_DH_GEX_INIT); |
ssh_dispatch_set(ssh, SSH2_MSG_KEX_DH_GEX_INIT, &input_kex_dh_gex_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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static int |
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input_kex_dh_gex_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 || |
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kex->load_host_private_key == NULL) { |
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r = SSH_ERR_INVALID_ARGUMENT; |
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goto out; |
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} |
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if ((server_host_public = kex->load_host_public_key(kex->hostkey_type, |
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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("kexgex_server: BN_new failed"); |
&sbloblen)) != 0) |
if (BN_bin2bn(kbuf, kout, shared_secret) == NULL) |
goto out; |
fatal("kexgex_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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if (type == SSH2_MSG_KEX_DH_GEX_REQUEST_OLD) |
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omin = min = omax = max = -1; |
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/* calc H */ |
/* calc H */ |
kexgex_hash( |
hashlen = sizeof(hash); |
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if ((r = kexgex_hash( |
kex->hash_alg, |
kex->hash_alg, |
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, |
omin, onbits, omax, |
kex->min, kex->nbits, kex->max, |
dh->p, dh->g, |
kex->dh->p, kex->dh->g, |
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 */ |
debug("SSH2_MSG_KEX_DH_GEX_REPLY sent"); |
if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_DH_GEX_REPLY)) != 0 || |
packet_start(SSH2_MSG_KEX_DH_GEX_REPLY); |
(r = sshpkt_put_string(ssh, server_host_key_blob, sbloblen)) != 0 || |
packet_put_string(server_host_key_blob, sbloblen); |
(r = sshpkt_put_bignum2(ssh, kex->dh->pub_key)) != 0 || /* f */ |
packet_put_bignum2(dh->pub_key); /* f */ |
(r = sshpkt_put_string(ssh, signature, slen)) != 0 || |
packet_put_string(signature, slen); |
(r = sshpkt_send(ssh)) != 0) |
packet_send(); |
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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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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} |
} |