version 1.10, 2000/05/08 17:42:25 |
version 1.10.2.3, 2000/11/08 21:31:30 |
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* 2. Redistributions in binary form must reproduce the above copyright |
* 2. Redistributions in binary form must reproduce the above copyright |
* notice, this list of conditions and the following disclaimer in the |
* notice, this list of conditions and the following disclaimer in the |
* documentation and/or other materials provided with the distribution. |
* documentation and/or other materials provided with the distribution. |
* 3. All advertising materials mentioning features or use of this software |
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* must display the following acknowledgement: |
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* This product includes software developed by Markus Friedl. |
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* 4. The name of the author may not be used to endorse or promote products |
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* derived from this software without specific prior written permission. |
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* |
* |
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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#include "rsa.h" |
#include "rsa.h" |
#include "buffer.h" |
#include "buffer.h" |
#include "packet.h" |
#include "packet.h" |
#include "cipher.h" |
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#include "uidswap.h" |
#include "uidswap.h" |
#include "compat.h" |
#include "compat.h" |
#include "readconf.h" |
#include "readconf.h" |
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#include "dsa.h" |
#include "dsa.h" |
#include "sshconnect.h" |
#include "sshconnect.h" |
#include "authfile.h" |
#include "authfile.h" |
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#include "cli.h" |
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#include "dispatch.h" |
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#include "authfd.h" |
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void ssh_dh1_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *); |
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void ssh_dhgex_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *); |
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/* import */ |
/* import */ |
extern char *client_version_string; |
extern char *client_version_string; |
extern char *server_version_string; |
extern char *server_version_string; |
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void |
void |
ssh_kex2(char *host, struct sockaddr *hostaddr) |
ssh_kex2(char *host, struct sockaddr *hostaddr) |
{ |
{ |
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int i, plen; |
Kex *kex; |
Kex *kex; |
char *cprop[PROPOSAL_MAX]; |
Buffer *client_kexinit, *server_kexinit; |
char *sprop[PROPOSAL_MAX]; |
char *sprop[PROPOSAL_MAX]; |
Buffer *client_kexinit; |
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Buffer *server_kexinit; |
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int payload_len, dlen; |
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unsigned int klen, kout; |
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char *ptr; |
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char *signature = NULL; |
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unsigned int slen; |
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char *server_host_key_blob = NULL; |
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Key *server_host_key; |
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unsigned int sbloblen; |
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DH *dh; |
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BIGNUM *dh_server_pub = 0; |
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BIGNUM *shared_secret = 0; |
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int i; |
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unsigned char *kbuf; |
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unsigned char *hash; |
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/* KEXINIT */ |
if (options.ciphers == NULL) { |
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if (options.cipher == SSH_CIPHER_3DES) { |
debug("Sending KEX init."); |
options.ciphers = "3des-cbc"; |
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} else if (options.cipher == SSH_CIPHER_BLOWFISH) { |
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options.ciphers = "blowfish-cbc"; |
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} else if (options.cipher == SSH_CIPHER_DES) { |
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fatal("cipher DES not supported for protocol version 2"); |
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} |
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} |
if (options.ciphers != NULL) { |
if (options.ciphers != NULL) { |
myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
} else if (options.cipher == SSH_CIPHER_3DES) { |
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myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
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myproposal[PROPOSAL_ENC_ALGS_STOC] = |
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cipher_name(SSH_CIPHER_3DES_CBC); |
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} else if (options.cipher == SSH_CIPHER_BLOWFISH) { |
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myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
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myproposal[PROPOSAL_ENC_ALGS_STOC] = |
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cipher_name(SSH_CIPHER_BLOWFISH_CBC); |
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} |
} |
if (options.compression) { |
if (options.compression) { |
myproposal[PROPOSAL_COMP_ALGS_CTOS] = "zlib"; |
myproposal[PROPOSAL_COMP_ALGS_CTOS] = "zlib"; |
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myproposal[PROPOSAL_COMP_ALGS_CTOS] = "none"; |
myproposal[PROPOSAL_COMP_ALGS_CTOS] = "none"; |
myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; |
myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; |
} |
} |
for (i = 0; i < PROPOSAL_MAX; i++) |
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cprop[i] = xstrdup(myproposal[i]); |
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client_kexinit = kex_init(cprop); |
/* buffers with raw kexinit messages */ |
packet_start(SSH2_MSG_KEXINIT); |
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packet_put_raw(buffer_ptr(client_kexinit), buffer_len(client_kexinit)); |
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packet_send(); |
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packet_write_wait(); |
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debug("done"); |
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packet_read_expect(&payload_len, SSH2_MSG_KEXINIT); |
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/* save payload for session_id */ |
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server_kexinit = xmalloc(sizeof(*server_kexinit)); |
server_kexinit = xmalloc(sizeof(*server_kexinit)); |
buffer_init(server_kexinit); |
buffer_init(server_kexinit); |
ptr = packet_get_raw(&payload_len); |
client_kexinit = kex_init(myproposal); |
buffer_append(server_kexinit, ptr, payload_len); |
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/* skip cookie */ |
/* algorithm negotiation */ |
for (i = 0; i < 16; i++) |
kex_exchange_kexinit(client_kexinit, server_kexinit, sprop); |
(void) packet_get_char(); |
kex = kex_choose_conf(myproposal, sprop, 0); |
/* kex init proposal strings */ |
for (i = 0; i < PROPOSAL_MAX; i++) |
for (i = 0; i < PROPOSAL_MAX; i++) { |
xfree(sprop[i]); |
sprop[i] = packet_get_string(NULL); |
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debug("got kexinit string: %s", sprop[i]); |
/* server authentication and session key agreement */ |
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switch(kex->kex_type) { |
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case DH_GRP1_SHA1: |
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ssh_dh1_client(kex, host, hostaddr, |
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client_kexinit, server_kexinit); |
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break; |
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case DH_GEX_SHA1: |
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ssh_dhgex_client(kex, host, hostaddr, client_kexinit, |
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server_kexinit); |
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break; |
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default: |
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fatal("Unsupported key exchange %d", kex->kex_type); |
} |
} |
i = (int) packet_get_char(); |
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debug("first kex follow == %d", i); |
buffer_free(client_kexinit); |
i = packet_get_int(); |
buffer_free(server_kexinit); |
debug("reserved == %d", i); |
xfree(client_kexinit); |
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xfree(server_kexinit); |
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debug("Wait SSH2_MSG_NEWKEYS."); |
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packet_read_expect(&plen, SSH2_MSG_NEWKEYS); |
packet_done(); |
packet_done(); |
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debug("GOT SSH2_MSG_NEWKEYS."); |
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debug("done read kexinit"); |
debug("send SSH2_MSG_NEWKEYS."); |
kex = kex_choose_conf(cprop, sprop, 0); |
packet_start(SSH2_MSG_NEWKEYS); |
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packet_send(); |
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packet_write_wait(); |
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debug("done: send SSH2_MSG_NEWKEYS."); |
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/* KEXDH */ |
#ifdef DEBUG_KEXDH |
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/* send 1st encrypted/maced/compressed message */ |
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packet_start(SSH2_MSG_IGNORE); |
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packet_put_cstring("markus"); |
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packet_send(); |
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packet_write_wait(); |
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#endif |
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debug("done: KEX2."); |
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} |
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debug("Sending SSH2_MSG_KEXDH_INIT."); |
/* diffie-hellman-group1-sha1 */ |
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void |
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ssh_dh1_client(Kex *kex, char *host, struct sockaddr *hostaddr, |
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Buffer *client_kexinit, Buffer *server_kexinit) |
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{ |
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#ifdef DEBUG_KEXDH |
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int i; |
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#endif |
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int plen, dlen; |
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unsigned int klen, kout; |
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char *signature = NULL; |
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unsigned int slen; |
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char *server_host_key_blob = NULL; |
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Key *server_host_key; |
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unsigned int sbloblen; |
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DH *dh; |
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BIGNUM *dh_server_pub = 0; |
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BIGNUM *shared_secret = 0; |
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unsigned char *kbuf; |
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unsigned char *hash; |
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debug("Sending SSH2_MSG_KEXDH_INIT."); |
/* generate and send 'e', client DH public key */ |
/* generate and send 'e', client DH public key */ |
dh = dh_new_group1(); |
dh = dh_new_group1(); |
packet_start(SSH2_MSG_KEXDH_INIT); |
packet_start(SSH2_MSG_KEXDH_INIT); |
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#ifdef DEBUG_KEXDH |
#ifdef DEBUG_KEXDH |
fprintf(stderr, "\np= "); |
fprintf(stderr, "\np= "); |
bignum_print(dh->p); |
BN_print_fp(stderr, dh->p); |
fprintf(stderr, "\ng= "); |
fprintf(stderr, "\ng= "); |
bignum_print(dh->g); |
BN_print_fp(stderr, dh->g); |
fprintf(stderr, "\npub= "); |
fprintf(stderr, "\npub= "); |
bignum_print(dh->pub_key); |
BN_print_fp(stderr, dh->pub_key); |
fprintf(stderr, "\n"); |
fprintf(stderr, "\n"); |
DHparams_print_fp(stderr, dh); |
DHparams_print_fp(stderr, dh); |
#endif |
#endif |
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debug("Wait SSH2_MSG_KEXDH_REPLY."); |
debug("Wait SSH2_MSG_KEXDH_REPLY."); |
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packet_read_expect(&payload_len, SSH2_MSG_KEXDH_REPLY); |
packet_read_expect(&plen, SSH2_MSG_KEXDH_REPLY); |
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debug("Got SSH2_MSG_KEXDH_REPLY."); |
debug("Got SSH2_MSG_KEXDH_REPLY."); |
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fatal("cannot decode server_host_key_blob"); |
fatal("cannot decode server_host_key_blob"); |
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check_host_key(host, hostaddr, server_host_key, |
check_host_key(host, hostaddr, server_host_key, |
options.user_hostfile2, options.system_hostfile2); |
options.user_hostfile2, options.system_hostfile2); |
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/* DH paramter f, server public DH key */ |
/* DH paramter f, server public DH key */ |
dh_server_pub = BN_new(); |
dh_server_pub = BN_new(); |
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#ifdef DEBUG_KEXDH |
#ifdef DEBUG_KEXDH |
fprintf(stderr, "\ndh_server_pub= "); |
fprintf(stderr, "\ndh_server_pub= "); |
bignum_print(dh_server_pub); |
BN_print_fp(stderr, dh_server_pub); |
fprintf(stderr, "\n"); |
fprintf(stderr, "\n"); |
debug("bits %d", BN_num_bits(dh_server_pub)); |
debug("bits %d", BN_num_bits(dh_server_pub)); |
#endif |
#endif |
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shared_secret |
shared_secret |
); |
); |
xfree(server_host_key_blob); |
xfree(server_host_key_blob); |
buffer_free(client_kexinit); |
DH_free(dh); |
buffer_free(server_kexinit); |
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xfree(client_kexinit); |
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xfree(server_kexinit); |
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#ifdef DEBUG_KEXDH |
#ifdef DEBUG_KEXDH |
fprintf(stderr, "hash == "); |
fprintf(stderr, "hash == "); |
for (i = 0; i< 20; i++) |
for (i = 0; i< 20; i++) |
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kex_derive_keys(kex, hash, shared_secret); |
kex_derive_keys(kex, hash, shared_secret); |
packet_set_kex(kex); |
packet_set_kex(kex); |
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/* have keys, free DH */ |
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DH_free(dh); |
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/* save session id */ |
/* save session id */ |
session_id2_len = 20; |
session_id2_len = 20; |
session_id2 = xmalloc(session_id2_len); |
session_id2 = xmalloc(session_id2_len); |
memcpy(session_id2, hash, session_id2_len); |
memcpy(session_id2, hash, session_id2_len); |
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} |
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debug("Wait SSH2_MSG_NEWKEYS."); |
/* diffie-hellman-group-exchange-sha1 */ |
packet_read_expect(&payload_len, SSH2_MSG_NEWKEYS); |
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packet_done(); |
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debug("GOT SSH2_MSG_NEWKEYS."); |
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debug("send SSH2_MSG_NEWKEYS."); |
/* |
packet_start(SSH2_MSG_NEWKEYS); |
* Estimates the group order for a Diffie-Hellman group that has an |
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* attack complexity approximately the same as O(2**bits). Estimate |
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* with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3))) |
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*/ |
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int |
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dh_estimate(int bits) |
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{ |
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if (bits < 64) |
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return (512); /* O(2**63) */ |
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if (bits < 128) |
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return (1024); /* O(2**86) */ |
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if (bits < 192) |
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return (2048); /* O(2**116) */ |
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return (4096); /* O(2**156) */ |
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} |
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void |
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ssh_dhgex_client(Kex *kex, char *host, struct sockaddr *hostaddr, |
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Buffer *client_kexinit, Buffer *server_kexinit) |
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{ |
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#ifdef DEBUG_KEXDH |
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int i; |
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#endif |
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int plen, dlen; |
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unsigned int klen, kout; |
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char *signature = NULL; |
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unsigned int slen, nbits; |
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char *server_host_key_blob = NULL; |
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Key *server_host_key; |
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unsigned int sbloblen; |
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DH *dh; |
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BIGNUM *dh_server_pub = 0; |
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BIGNUM *shared_secret = 0; |
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BIGNUM *p = 0, *g = 0; |
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unsigned char *kbuf; |
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unsigned char *hash; |
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nbits = dh_estimate(kex->enc[MODE_OUT].cipher->key_len * 8); |
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debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST."); |
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packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST); |
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packet_put_int(nbits); |
packet_send(); |
packet_send(); |
packet_write_wait(); |
packet_write_wait(); |
debug("done: send SSH2_MSG_NEWKEYS."); |
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#ifdef DEBUG_KEXDH |
#ifdef DEBUG_KEXDH |
/* send 1st encrypted/maced/compressed message */ |
fprintf(stderr, "\nnbits = %d", nbits); |
packet_start(SSH2_MSG_IGNORE); |
#endif |
packet_put_cstring("markus"); |
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debug("Wait SSH2_MSG_KEX_DH_GEX_GROUP."); |
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packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_GROUP); |
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debug("Got SSH2_MSG_KEX_DH_GEX_GROUP."); |
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if ((p = BN_new()) == NULL) |
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fatal("BN_new"); |
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packet_get_bignum2(p, &dlen); |
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if ((g = BN_new()) == NULL) |
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fatal("BN_new"); |
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packet_get_bignum2(g, &dlen); |
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if ((dh = dh_new_group(g, p)) == NULL) |
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fatal("dh_new_group"); |
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#ifdef DEBUG_KEXDH |
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fprintf(stderr, "\np= "); |
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BN_print_fp(stderr, dh->p); |
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fprintf(stderr, "\ng= "); |
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BN_print_fp(stderr, dh->g); |
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fprintf(stderr, "\npub= "); |
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BN_print_fp(stderr, dh->pub_key); |
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fprintf(stderr, "\n"); |
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DHparams_print_fp(stderr, dh); |
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#endif |
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debug("Sending SSH2_MSG_KEX_DH_GEX_INIT."); |
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/* generate and send 'e', client DH public key */ |
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packet_start(SSH2_MSG_KEX_DH_GEX_INIT); |
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packet_put_bignum2(dh->pub_key); |
packet_send(); |
packet_send(); |
packet_write_wait(); |
packet_write_wait(); |
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debug("Wait SSH2_MSG_KEX_DH_GEX_REPLY."); |
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packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_REPLY); |
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debug("Got SSH2_MSG_KEXDH_REPLY."); |
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/* key, cert */ |
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server_host_key_blob = packet_get_string(&sbloblen); |
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server_host_key = dsa_key_from_blob(server_host_key_blob, sbloblen); |
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if (server_host_key == NULL) |
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fatal("cannot decode server_host_key_blob"); |
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check_host_key(host, hostaddr, server_host_key, |
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options.user_hostfile2, options.system_hostfile2); |
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/* DH paramter f, server public DH key */ |
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dh_server_pub = BN_new(); |
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if (dh_server_pub == NULL) |
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fatal("dh_server_pub == NULL"); |
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packet_get_bignum2(dh_server_pub, &dlen); |
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#ifdef DEBUG_KEXDH |
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fprintf(stderr, "\ndh_server_pub= "); |
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BN_print_fp(stderr, dh_server_pub); |
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fprintf(stderr, "\n"); |
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debug("bits %d", BN_num_bits(dh_server_pub)); |
#endif |
#endif |
debug("done: KEX2."); |
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/* signed H */ |
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signature = packet_get_string(&slen); |
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packet_done(); |
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if (!dh_pub_is_valid(dh, dh_server_pub)) |
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packet_disconnect("bad server public DH value"); |
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klen = DH_size(dh); |
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kbuf = xmalloc(klen); |
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kout = DH_compute_key(kbuf, dh_server_pub, dh); |
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#ifdef DEBUG_KEXDH |
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debug("shared secret: len %d/%d", klen, kout); |
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fprintf(stderr, "shared secret == "); |
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for (i = 0; i< kout; i++) |
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fprintf(stderr, "%02x", (kbuf[i])&0xff); |
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fprintf(stderr, "\n"); |
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#endif |
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shared_secret = BN_new(); |
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BN_bin2bn(kbuf, kout, shared_secret); |
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memset(kbuf, 0, klen); |
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xfree(kbuf); |
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/* calc and verify H */ |
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hash = kex_hash_gex( |
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client_version_string, |
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server_version_string, |
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buffer_ptr(client_kexinit), buffer_len(client_kexinit), |
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buffer_ptr(server_kexinit), buffer_len(server_kexinit), |
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server_host_key_blob, sbloblen, |
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nbits, dh->p, dh->g, |
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dh->pub_key, |
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dh_server_pub, |
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shared_secret |
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); |
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xfree(server_host_key_blob); |
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DH_free(dh); |
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#ifdef DEBUG_KEXDH |
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fprintf(stderr, "hash == "); |
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for (i = 0; i< 20; i++) |
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fprintf(stderr, "%02x", (hash[i])&0xff); |
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fprintf(stderr, "\n"); |
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#endif |
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if (dsa_verify(server_host_key, (unsigned char *)signature, slen, hash, 20) != 1) |
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fatal("dsa_verify failed for server_host_key"); |
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key_free(server_host_key); |
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kex_derive_keys(kex, hash, shared_secret); |
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packet_set_kex(kex); |
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/* save session id */ |
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session_id2_len = 20; |
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session_id2 = xmalloc(session_id2_len); |
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memcpy(session_id2, hash, session_id2_len); |
} |
} |
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/* |
/* |
* Authenticate user |
* Authenticate user |
*/ |
*/ |
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|
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typedef struct Authctxt Authctxt; |
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typedef struct Authmethod Authmethod; |
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|
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typedef int sign_cb_fn( |
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Authctxt *authctxt, Key *key, |
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unsigned char **sigp, int *lenp, unsigned char *data, int datalen); |
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|
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struct Authctxt { |
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const char *server_user; |
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const char *host; |
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const char *service; |
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AuthenticationConnection *agent; |
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Authmethod *method; |
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int success; |
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}; |
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struct Authmethod { |
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char *name; /* string to compare against server's list */ |
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int (*userauth)(Authctxt *authctxt); |
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int *enabled; /* flag in option struct that enables method */ |
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int *batch_flag; /* flag in option struct that disables method */ |
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}; |
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void input_userauth_success(int type, int plen, void *ctxt); |
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void input_userauth_failure(int type, int plen, void *ctxt); |
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void input_userauth_error(int type, int plen, void *ctxt); |
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void input_userauth_info_req(int type, int plen, void *ctxt); |
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int userauth_none(Authctxt *authctxt); |
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int userauth_pubkey(Authctxt *authctxt); |
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int userauth_passwd(Authctxt *authctxt); |
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int userauth_kbdint(Authctxt *authctxt); |
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|
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void authmethod_clear(); |
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Authmethod *authmethod_get(char *authlist); |
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Authmethod *authmethod_lookup(const char *name); |
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Authmethod authmethods[] = { |
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{"publickey", |
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userauth_pubkey, |
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&options.dsa_authentication, |
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NULL}, |
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{"password", |
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userauth_passwd, |
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&options.password_authentication, |
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&options.batch_mode}, |
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{"keyboard-interactive", |
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userauth_kbdint, |
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&options.kbd_interactive_authentication, |
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&options.batch_mode}, |
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{"none", |
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userauth_none, |
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NULL, |
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NULL}, |
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{NULL, NULL, NULL, NULL} |
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}; |
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|
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void |
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ssh_userauth2(const char *server_user, char *host) |
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{ |
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Authctxt authctxt; |
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int type; |
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int plen; |
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|
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debug("send SSH2_MSG_SERVICE_REQUEST"); |
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packet_start(SSH2_MSG_SERVICE_REQUEST); |
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packet_put_cstring("ssh-userauth"); |
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packet_send(); |
|
packet_write_wait(); |
|
type = packet_read(&plen); |
|
if (type != SSH2_MSG_SERVICE_ACCEPT) { |
|
fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type); |
|
} |
|
if (packet_remaining() > 0) { |
|
char *reply = packet_get_string(&plen); |
|
debug("service_accept: %s", reply); |
|
xfree(reply); |
|
packet_done(); |
|
} else { |
|
debug("buggy server: service_accept w/o service"); |
|
} |
|
packet_done(); |
|
debug("got SSH2_MSG_SERVICE_ACCEPT"); |
|
|
|
/* setup authentication context */ |
|
authctxt.agent = ssh_get_authentication_connection(); |
|
authctxt.server_user = server_user; |
|
authctxt.host = host; |
|
authctxt.service = "ssh-connection"; /* service name */ |
|
authctxt.success = 0; |
|
authctxt.method = authmethod_lookup("none"); |
|
if (authctxt.method == NULL) |
|
fatal("ssh_userauth2: internal error: cannot send userauth none request"); |
|
authmethod_clear(); |
|
|
|
/* initial userauth request */ |
|
userauth_none(&authctxt); |
|
|
|
dispatch_init(&input_userauth_error); |
|
dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); |
|
dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); |
|
dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ |
|
|
|
if (authctxt.agent != NULL) |
|
ssh_close_authentication_connection(authctxt.agent); |
|
|
|
debug("ssh-userauth2 successfull: method %s", authctxt.method->name); |
|
} |
|
void |
|
input_userauth_error(int type, int plen, void *ctxt) |
|
{ |
|
fatal("input_userauth_error: bad message during authentication"); |
|
} |
|
void |
|
input_userauth_success(int type, int plen, void *ctxt) |
|
{ |
|
Authctxt *authctxt = ctxt; |
|
if (authctxt == NULL) |
|
fatal("input_userauth_success: no authentication context"); |
|
authctxt->success = 1; /* break out */ |
|
} |
|
void |
|
input_userauth_failure(int type, int plen, void *ctxt) |
|
{ |
|
Authmethod *method = NULL; |
|
Authctxt *authctxt = ctxt; |
|
char *authlist = NULL; |
|
int partial; |
|
|
|
if (authctxt == NULL) |
|
fatal("input_userauth_failure: no authentication context"); |
|
|
|
authlist = packet_get_string(NULL); |
|
partial = packet_get_char(); |
|
packet_done(); |
|
|
|
if (partial != 0) |
|
debug("partial success"); |
|
debug("authentications that can continue: %s", authlist); |
|
|
|
for (;;) { |
|
method = authmethod_get(authlist); |
|
if (method == NULL) |
|
fatal("Unable to find an authentication method"); |
|
authctxt->method = method; |
|
if (method->userauth(authctxt) != 0) { |
|
debug2("we sent a %s packet, wait for reply", method->name); |
|
break; |
|
} else { |
|
debug2("we did not send a packet, disable method"); |
|
method->enabled = NULL; |
|
} |
|
} |
|
xfree(authlist); |
|
} |
|
|
int |
int |
ssh2_try_passwd(const char *server_user, const char *host, const char *service) |
userauth_none(Authctxt *authctxt) |
{ |
{ |
|
/* initial userauth request */ |
|
packet_start(SSH2_MSG_USERAUTH_REQUEST); |
|
packet_put_cstring(authctxt->server_user); |
|
packet_put_cstring(authctxt->service); |
|
packet_put_cstring(authctxt->method->name); |
|
packet_send(); |
|
packet_write_wait(); |
|
return 1; |
|
} |
|
|
|
int |
|
userauth_passwd(Authctxt *authctxt) |
|
{ |
static int attempt = 0; |
static int attempt = 0; |
char prompt[80]; |
char prompt[80]; |
char *password; |
char *password; |
|
|
if (attempt++ > options.number_of_password_prompts) |
if (attempt++ >= options.number_of_password_prompts) |
return 0; |
return 0; |
|
|
|
if(attempt != 1) |
|
error("Permission denied, please try again."); |
|
|
snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ", |
snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ", |
server_user, host); |
authctxt->server_user, authctxt->host); |
password = read_passphrase(prompt, 0); |
password = read_passphrase(prompt, 0); |
packet_start(SSH2_MSG_USERAUTH_REQUEST); |
packet_start(SSH2_MSG_USERAUTH_REQUEST); |
packet_put_cstring(server_user); |
packet_put_cstring(authctxt->server_user); |
packet_put_cstring(service); |
packet_put_cstring(authctxt->service); |
packet_put_cstring("password"); |
packet_put_cstring(authctxt->method->name); |
packet_put_char(0); |
packet_put_char(0); |
packet_put_cstring(password); |
packet_put_cstring(password); |
memset(password, 0, strlen(password)); |
memset(password, 0, strlen(password)); |
|
|
} |
} |
|
|
int |
int |
ssh2_try_pubkey(char *filename, |
sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) |
const char *server_user, const char *host, const char *service) |
|
{ |
{ |
Buffer b; |
Buffer b; |
Key *k; |
|
unsigned char *blob, *signature; |
unsigned char *blob, *signature; |
int bloblen, slen; |
int bloblen, slen; |
struct stat st; |
int skip = 0; |
|
int ret = -1; |
|
int have_sig = 1; |
|
|
if (stat(filename, &st) != 0) { |
|
debug("key does not exist: %s", filename); |
|
return 0; |
|
} |
|
debug("try pubkey: %s", filename); |
|
|
|
k = key_new(KEY_DSA); |
|
if (!load_private_key(filename, "", k, NULL)) { |
|
int success = 0; |
|
char *passphrase; |
|
char prompt[300]; |
|
snprintf(prompt, sizeof prompt, |
|
"Enter passphrase for DSA key '%.100s': ", |
|
filename); |
|
passphrase = read_passphrase(prompt, 0); |
|
success = load_private_key(filename, passphrase, k, NULL); |
|
memset(passphrase, 0, strlen(passphrase)); |
|
xfree(passphrase); |
|
if (!success) |
|
return 0; |
|
} |
|
dsa_make_key_blob(k, &blob, &bloblen); |
dsa_make_key_blob(k, &blob, &bloblen); |
|
|
/* data to be signed */ |
/* data to be signed */ |
buffer_init(&b); |
buffer_init(&b); |
buffer_append(&b, session_id2, session_id2_len); |
if (datafellows & SSH_OLD_SESSIONID) { |
|
buffer_append(&b, session_id2, session_id2_len); |
|
skip = session_id2_len; |
|
} else { |
|
buffer_put_string(&b, session_id2, session_id2_len); |
|
skip = buffer_len(&b); |
|
} |
buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
buffer_put_cstring(&b, server_user); |
buffer_put_cstring(&b, authctxt->server_user); |
buffer_put_cstring(&b, |
buffer_put_cstring(&b, |
datafellows & SSH_BUG_PUBKEYAUTH ? |
datafellows & SSH_BUG_PUBKEYAUTH ? |
"ssh-userauth" : |
"ssh-userauth" : |
service); |
authctxt->service); |
buffer_put_cstring(&b, "publickey"); |
buffer_put_cstring(&b, authctxt->method->name); |
buffer_put_char(&b, 1); |
buffer_put_char(&b, have_sig); |
buffer_put_cstring(&b, KEX_DSS); |
buffer_put_cstring(&b, KEX_DSS); |
buffer_put_string(&b, blob, bloblen); |
buffer_put_string(&b, blob, bloblen); |
|
|
/* generate signature */ |
/* generate signature */ |
dsa_sign(k, &signature, &slen, buffer_ptr(&b), buffer_len(&b)); |
ret = (*sign_callback)(authctxt, k, &signature, &slen, buffer_ptr(&b), buffer_len(&b)); |
key_free(k); |
if (ret == -1) { |
|
xfree(blob); |
|
buffer_free(&b); |
|
return 0; |
|
} |
#ifdef DEBUG_DSS |
#ifdef DEBUG_DSS |
buffer_dump(&b); |
buffer_dump(&b); |
#endif |
#endif |
if (datafellows & SSH_BUG_PUBKEYAUTH) { |
if (datafellows & SSH_BUG_PUBKEYAUTH) { |
/* e.g. ssh-2.0.13: data-to-be-signed != data-on-the-wire */ |
|
buffer_clear(&b); |
buffer_clear(&b); |
buffer_append(&b, session_id2, session_id2_len); |
buffer_append(&b, session_id2, session_id2_len); |
buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
buffer_put_cstring(&b, server_user); |
buffer_put_cstring(&b, authctxt->server_user); |
buffer_put_cstring(&b, service); |
buffer_put_cstring(&b, authctxt->service); |
buffer_put_cstring(&b, "publickey"); |
buffer_put_cstring(&b, authctxt->method->name); |
buffer_put_char(&b, 1); |
buffer_put_char(&b, have_sig); |
buffer_put_cstring(&b, KEX_DSS); |
buffer_put_cstring(&b, KEX_DSS); |
buffer_put_string(&b, blob, bloblen); |
buffer_put_string(&b, blob, bloblen); |
} |
} |
|
|
xfree(signature); |
xfree(signature); |
|
|
/* skip session id and packet type */ |
/* skip session id and packet type */ |
if (buffer_len(&b) < session_id2_len + 1) |
if (buffer_len(&b) < skip + 1) |
fatal("ssh2_try_pubkey: internal error"); |
fatal("userauth_pubkey: internal error"); |
buffer_consume(&b, session_id2_len + 1); |
buffer_consume(&b, skip + 1); |
|
|
/* put remaining data from buffer into packet */ |
/* put remaining data from buffer into packet */ |
packet_start(SSH2_MSG_USERAUTH_REQUEST); |
packet_start(SSH2_MSG_USERAUTH_REQUEST); |
|
|
/* send */ |
/* send */ |
packet_send(); |
packet_send(); |
packet_write_wait(); |
packet_write_wait(); |
|
|
return 1; |
return 1; |
} |
} |
|
|
void |
/* sign callback */ |
ssh_userauth2(const char *server_user, char *host) |
int dsa_sign_cb(Authctxt *authctxt, Key *key, unsigned char **sigp, int *lenp, |
|
unsigned char *data, int datalen) |
{ |
{ |
int type; |
return dsa_sign(key, sigp, lenp, data, datalen); |
int plen; |
} |
int sent; |
|
unsigned int dlen; |
|
int partial; |
|
int i = 0; |
|
char *auths; |
|
char *service = "ssh-connection"; /* service name */ |
|
|
|
debug("send SSH2_MSG_SERVICE_REQUEST"); |
int |
packet_start(SSH2_MSG_SERVICE_REQUEST); |
userauth_pubkey_identity(Authctxt *authctxt, char *filename) |
packet_put_cstring("ssh-userauth"); |
{ |
packet_send(); |
Key *k; |
packet_write_wait(); |
int i, ret, try_next; |
|
struct stat st; |
|
|
type = packet_read(&plen); |
if (stat(filename, &st) != 0) { |
if (type != SSH2_MSG_SERVICE_ACCEPT) { |
debug("key does not exist: %s", filename); |
fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type); |
return 0; |
} |
} |
if (packet_remaining() > 0) { |
debug("try pubkey: %s", filename); |
char *reply = packet_get_string(&plen); |
|
debug("service_accept: %s", reply); |
k = key_new(KEY_DSA); |
xfree(reply); |
if (!load_private_key(filename, "", k, NULL)) { |
|
int success = 0; |
|
char *passphrase; |
|
char prompt[300]; |
|
snprintf(prompt, sizeof prompt, |
|
"Enter passphrase for %s key '%.100s': ", |
|
key_type(k), filename); |
|
for (i = 0; i < options.number_of_password_prompts; i++) { |
|
passphrase = read_passphrase(prompt, 0); |
|
if (strcmp(passphrase, "") != 0) { |
|
success = load_private_key(filename, passphrase, k, NULL); |
|
try_next = 0; |
|
} else { |
|
debug2("no passphrase given, try next key"); |
|
try_next = 1; |
|
} |
|
memset(passphrase, 0, strlen(passphrase)); |
|
xfree(passphrase); |
|
if (success || try_next) |
|
break; |
|
debug2("bad passphrase given, try again..."); |
|
} |
|
if (!success) { |
|
key_free(k); |
|
return 0; |
|
} |
|
} |
|
ret = sign_and_send_pubkey(authctxt, k, dsa_sign_cb); |
|
key_free(k); |
|
return ret; |
|
} |
|
|
|
/* sign callback */ |
|
int agent_sign_cb(Authctxt *authctxt, Key *key, unsigned char **sigp, int *lenp, |
|
unsigned char *data, int datalen) |
|
{ |
|
return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen); |
|
} |
|
|
|
int |
|
userauth_pubkey_agent(Authctxt *authctxt) |
|
{ |
|
static int called = 0; |
|
char *comment; |
|
Key *k; |
|
int ret; |
|
|
|
if (called == 0) { |
|
k = ssh_get_first_identity(authctxt->agent, &comment, 2); |
|
called = 1; |
} else { |
} else { |
/* payload empty for ssh-2.0.13 ?? */ |
k = ssh_get_next_identity(authctxt->agent, &comment, 2); |
debug("buggy server: service_accept w/o service"); |
|
} |
} |
packet_done(); |
if (k == NULL) { |
debug("got SSH2_MSG_SERVICE_ACCEPT"); |
debug2("no more DSA keys from agent"); |
|
return 0; |
|
} |
|
debug("trying DSA agent key %s", comment); |
|
xfree(comment); |
|
ret = sign_and_send_pubkey(authctxt, k, agent_sign_cb); |
|
key_free(k); |
|
return ret; |
|
} |
|
|
/* INITIAL request for auth */ |
int |
|
userauth_pubkey(Authctxt *authctxt) |
|
{ |
|
static int idx = 0; |
|
int sent = 0; |
|
|
|
if (authctxt->agent != NULL) |
|
sent = userauth_pubkey_agent(authctxt); |
|
while (sent == 0 && idx < options.num_identity_files2) |
|
sent = userauth_pubkey_identity(authctxt, options.identity_files2[idx++]); |
|
return sent; |
|
} |
|
|
|
/* |
|
* Send userauth request message specifying keyboard-interactive method. |
|
*/ |
|
int |
|
userauth_kbdint(Authctxt *authctxt) |
|
{ |
|
static int attempt = 0; |
|
|
|
if (attempt++ >= options.number_of_password_prompts) |
|
return 0; |
|
|
|
debug2("userauth_kbdint"); |
packet_start(SSH2_MSG_USERAUTH_REQUEST); |
packet_start(SSH2_MSG_USERAUTH_REQUEST); |
packet_put_cstring(server_user); |
packet_put_cstring(authctxt->server_user); |
packet_put_cstring(service); |
packet_put_cstring(authctxt->service); |
packet_put_cstring("none"); |
packet_put_cstring(authctxt->method->name); |
|
packet_put_cstring(""); /* lang */ |
|
packet_put_cstring(options.kbd_interactive_devices ? |
|
options.kbd_interactive_devices : ""); |
packet_send(); |
packet_send(); |
packet_write_wait(); |
packet_write_wait(); |
|
|
for (;;) { |
dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); |
sent = 0; |
return 1; |
type = packet_read(&plen); |
} |
if (type == SSH2_MSG_USERAUTH_SUCCESS) |
|
|
/* |
|
* parse SSH2_MSG_USERAUTH_INFO_REQUEST, prompt user and send |
|
* SSH2_MSG_USERAUTH_INFO_RESPONSE |
|
*/ |
|
void |
|
input_userauth_info_req(int type, int plen, void *ctxt) |
|
{ |
|
Authctxt *authctxt = ctxt; |
|
char *name = NULL; |
|
char *inst = NULL; |
|
char *lang = NULL; |
|
char *prompt = NULL; |
|
char *response = NULL; |
|
unsigned int num_prompts, i; |
|
int echo = 0; |
|
|
|
debug2("input_userauth_info_req"); |
|
|
|
if (authctxt == NULL) |
|
fatal("input_userauth_info_req: no authentication context"); |
|
|
|
name = packet_get_string(NULL); |
|
inst = packet_get_string(NULL); |
|
lang = packet_get_string(NULL); |
|
|
|
if (strlen(name) > 0) |
|
cli_mesg(name); |
|
xfree(name); |
|
|
|
if (strlen(inst) > 0) |
|
cli_mesg(inst); |
|
xfree(inst); |
|
xfree(lang); /* unused */ |
|
|
|
num_prompts = packet_get_int(); |
|
/* |
|
* Begin to build info response packet based on prompts requested. |
|
* We commit to providing the correct number of responses, so if |
|
* further on we run into a problem that prevents this, we have to |
|
* be sure and clean this up and send a correct error response. |
|
*/ |
|
packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); |
|
packet_put_int(num_prompts); |
|
|
|
for (i = 0; i < num_prompts; i++) { |
|
prompt = packet_get_string(NULL); |
|
echo = packet_get_char(); |
|
|
|
response = cli_prompt(prompt, echo); |
|
|
|
packet_put_cstring(response); |
|
memset(response, 0, strlen(response)); |
|
xfree(response); |
|
xfree(prompt); |
|
} |
|
packet_done(); /* done with parsing incoming message. */ |
|
|
|
packet_send(); |
|
packet_write_wait(); |
|
} |
|
|
|
/* find auth method */ |
|
|
|
#define DELIM "," |
|
|
|
static char *def_authlist = "publickey,password"; |
|
static char *authlist_current = NULL; /* clean copy used for comparison */ |
|
static char *authname_current = NULL; /* last used auth method */ |
|
static char *authlist_working = NULL; /* copy that gets modified by strtok_r() */ |
|
static char *authlist_state = NULL; /* state variable for strtok_r() */ |
|
|
|
/* |
|
* Before starting to use a new authentication method list sent by the |
|
* server, reset internal variables. This should also be called when |
|
* finished processing server list to free resources. |
|
*/ |
|
void |
|
authmethod_clear() |
|
{ |
|
if (authlist_current != NULL) { |
|
xfree(authlist_current); |
|
authlist_current = NULL; |
|
} |
|
if (authlist_working != NULL) { |
|
xfree(authlist_working); |
|
authlist_working = NULL; |
|
} |
|
if (authname_current != NULL) { |
|
xfree(authname_current); |
|
authlist_state = NULL; |
|
} |
|
if (authlist_state != NULL) |
|
authlist_state = NULL; |
|
return; |
|
} |
|
|
|
/* |
|
* given auth method name, if configurable options permit this method fill |
|
* in auth_ident field and return true, otherwise return false. |
|
*/ |
|
int |
|
authmethod_is_enabled(Authmethod *method) |
|
{ |
|
if (method == NULL) |
|
return 0; |
|
/* return false if options indicate this method is disabled */ |
|
if (method->enabled == NULL || *method->enabled == 0) |
|
return 0; |
|
/* return false if batch mode is enabled but method needs interactive mode */ |
|
if (method->batch_flag != NULL && *method->batch_flag != 0) |
|
return 0; |
|
return 1; |
|
} |
|
|
|
Authmethod * |
|
authmethod_lookup(const char *name) |
|
{ |
|
Authmethod *method = NULL; |
|
if (name != NULL) |
|
for (method = authmethods; method->name != NULL; method++) |
|
if (strcmp(name, method->name) == 0) |
|
return method; |
|
debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); |
|
return NULL; |
|
} |
|
|
|
/* |
|
* Given the authentication method list sent by the server, return the |
|
* next method we should try. If the server initially sends a nil list, |
|
* use a built-in default list. If the server sends a nil list after |
|
* previously sending a valid list, continue using the list originally |
|
* sent. |
|
*/ |
|
|
|
Authmethod * |
|
authmethod_get(char *authlist) |
|
{ |
|
char *name = NULL, *authname_old; |
|
Authmethod *method = NULL; |
|
|
|
/* Use a suitable default if we're passed a nil list. */ |
|
if (authlist == NULL || strlen(authlist) == 0) |
|
authlist = def_authlist; |
|
|
|
if (authlist_current == NULL || strcmp(authlist, authlist_current) != 0) { |
|
/* start over if passed a different list */ |
|
debug3("start over, passed a different list"); |
|
authmethod_clear(); |
|
authlist_current = xstrdup(authlist); |
|
authlist_working = xstrdup(authlist); |
|
name = strtok_r(authlist_working, DELIM, &authlist_state); |
|
} else { |
|
/* |
|
* try to use previously used authentication method |
|
* or continue to use previously passed list |
|
*/ |
|
name = (authname_current != NULL) ? |
|
authname_current : strtok_r(NULL, DELIM, &authlist_state); |
|
} |
|
|
|
while (name != NULL) { |
|
debug3("authmethod_lookup %s", name); |
|
method = authmethod_lookup(name); |
|
if (method != NULL && authmethod_is_enabled(method)) { |
|
debug3("authmethod_is_enabled %s", name); |
break; |
break; |
if (type != SSH2_MSG_USERAUTH_FAILURE) |
|
fatal("access denied: %d", type); |
|
/* SSH2_MSG_USERAUTH_FAILURE means: try again */ |
|
auths = packet_get_string(&dlen); |
|
debug("authentications that can continue: %s", auths); |
|
partial = packet_get_char(); |
|
packet_done(); |
|
if (partial) |
|
debug("partial success"); |
|
if (options.dsa_authentication && |
|
strstr(auths, "publickey") != NULL) { |
|
while (i < options.num_identity_files2) { |
|
sent = ssh2_try_pubkey( |
|
options.identity_files2[i++], |
|
server_user, host, service); |
|
if (sent) |
|
break; |
|
} |
|
} |
} |
if (!sent) { |
name = strtok_r(NULL, DELIM, &authlist_state); |
if (options.password_authentication && |
method = NULL; |
!options.batch_mode && |
|
strstr(auths, "password") != NULL) { |
|
sent = ssh2_try_passwd(server_user, host, service); |
|
} |
|
} |
|
if (!sent) |
|
fatal("Permission denied (%s).", auths); |
|
xfree(auths); |
|
} |
} |
packet_done(); |
|
debug("ssh-userauth2 successfull"); |
authname_old = authname_current; |
|
if (method != NULL) { |
|
debug("next auth method to try is %s", name); |
|
authname_current = xstrdup(name); |
|
} else { |
|
debug("no more auth methods to try"); |
|
authname_current = NULL; |
|
} |
|
|
|
if (authname_old != NULL) |
|
xfree(authname_old); |
|
|
|
return (method); |
} |
} |