version 1.12, 2000/10/11 20:27:23 |
version 1.12.2.5, 2001/09/27 00:15:42 |
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/* |
/* |
* Copyright (c) 2000 Markus Friedl. All rights reserved. |
* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. |
* |
* |
* Redistribution and use in source and binary forms, with or without |
* Redistribution and use in source and binary forms, with or without |
* modification, are permitted provided that the following conditions |
* modification, are permitted provided that the following conditions |
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#include "includes.h" |
#include "includes.h" |
RCSID("$OpenBSD$"); |
RCSID("$OpenBSD$"); |
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#include "ssh.h" |
#include <openssl/crypto.h> |
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#include "ssh2.h" |
#include "ssh2.h" |
#include "xmalloc.h" |
#include "xmalloc.h" |
#include "buffer.h" |
#include "buffer.h" |
#include "bufaux.h" |
#include "bufaux.h" |
#include "packet.h" |
#include "packet.h" |
#include "compat.h" |
#include "compat.h" |
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#include "cipher.h" |
#include <openssl/bn.h> |
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#include <openssl/dh.h> |
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#include <openssl/crypto.h> |
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#include <openssl/bio.h> |
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#include <openssl/bn.h> |
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#include <openssl/dh.h> |
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#include <openssl/pem.h> |
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#include "kex.h" |
#include "kex.h" |
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#include "key.h" |
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#include "log.h" |
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#include "mac.h" |
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#include "match.h" |
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#include "dispatch.h" |
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#define KEX_COOKIE_LEN 16 |
#define KEX_COOKIE_LEN 16 |
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Buffer * |
/* prototype */ |
kex_init(char *myproposal[PROPOSAL_MAX]) |
static void kex_kexinit_finish(Kex *); |
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static void kex_choose_conf(Kex *); |
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/* put algorithm proposal into buffer */ |
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static void |
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kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX]) |
{ |
{ |
int first_kex_packet_follows = 0; |
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unsigned char cookie[KEX_COOKIE_LEN]; |
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u_int32_t rand = 0; |
u_int32_t rand = 0; |
int i; |
int i; |
Buffer *ki = xmalloc(sizeof(*ki)); |
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buffer_clear(b); |
for (i = 0; i < KEX_COOKIE_LEN; i++) { |
for (i = 0; i < KEX_COOKIE_LEN; i++) { |
if (i % 4 == 0) |
if (i % 4 == 0) |
rand = arc4random(); |
rand = arc4random(); |
cookie[i] = rand & 0xff; |
buffer_put_char(b, rand & 0xff); |
rand >>= 8; |
rand >>= 8; |
} |
} |
buffer_init(ki); |
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buffer_append(ki, (char *)cookie, sizeof cookie); |
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for (i = 0; i < PROPOSAL_MAX; i++) |
for (i = 0; i < PROPOSAL_MAX; i++) |
buffer_put_cstring(ki, myproposal[i]); |
buffer_put_cstring(b, proposal[i]); |
buffer_put_char(ki, first_kex_packet_follows); |
buffer_put_char(b, 0); /* first_kex_packet_follows */ |
buffer_put_int(ki, 0); /* uint32 reserved */ |
buffer_put_int(b, 0); /* uint32 reserved */ |
return ki; |
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} |
} |
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/* send kexinit, parse and save reply */ |
/* parse buffer and return algorithm proposal */ |
void |
static char ** |
kex_exchange_kexinit( |
kex_buf2prop(Buffer *raw) |
Buffer *my_kexinit, Buffer *peer_kexint, |
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char *peer_proposal[PROPOSAL_MAX]) |
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{ |
{ |
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Buffer b; |
int i; |
int i; |
char *ptr; |
char **proposal; |
int plen; |
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debug("send KEXINIT"); |
proposal = xmalloc(PROPOSAL_MAX * sizeof(char *)); |
packet_start(SSH2_MSG_KEXINIT); |
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packet_put_raw(buffer_ptr(my_kexinit), buffer_len(my_kexinit)); |
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packet_send(); |
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packet_write_wait(); |
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debug("done"); |
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/* |
buffer_init(&b); |
* read and save raw KEXINIT payload in buffer. this is used during |
buffer_append(&b, buffer_ptr(raw), buffer_len(raw)); |
* computation of the session_id and the session keys. |
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*/ |
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debug("wait KEXINIT"); |
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packet_read_expect(&plen, SSH2_MSG_KEXINIT); |
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ptr = packet_get_raw(&plen); |
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buffer_append(peer_kexint, ptr, plen); |
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/* parse packet and save algorithm proposal */ |
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/* skip cookie */ |
/* skip cookie */ |
for (i = 0; i < KEX_COOKIE_LEN; i++) |
for (i = 0; i < KEX_COOKIE_LEN; i++) |
packet_get_char(); |
buffer_get_char(&b); |
/* extract kex init proposal strings */ |
/* extract kex init proposal strings */ |
for (i = 0; i < PROPOSAL_MAX; i++) { |
for (i = 0; i < PROPOSAL_MAX; i++) { |
peer_proposal[i] = packet_get_string(NULL); |
proposal[i] = buffer_get_string(&b,NULL); |
debug("got kexinit: %s", peer_proposal[i]); |
debug2("kex_parse_kexinit: %s", proposal[i]); |
} |
} |
/* first kex follow / reserved */ |
/* first kex follows / reserved */ |
i = packet_get_char(); |
i = buffer_get_char(&b); |
debug("first kex follow: %d ", i); |
debug2("kex_parse_kexinit: first_kex_follows %d ", i); |
i = packet_get_int(); |
i = buffer_get_int(&b); |
debug("reserved: %d ", i); |
debug2("kex_parse_kexinit: reserved %d ", i); |
packet_done(); |
buffer_free(&b); |
debug("done"); |
return proposal; |
} |
} |
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/* diffie-hellman-group1-sha1 */ |
static void |
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kex_prop_free(char **proposal) |
int |
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dh_pub_is_valid(DH *dh, BIGNUM *dh_pub) |
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{ |
{ |
int i; |
int i; |
int n = BN_num_bits(dh_pub); |
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int bits_set = 0; |
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if (dh_pub->neg) { |
for (i = 0; i < PROPOSAL_MAX; i++) |
log("invalid public DH value: negativ"); |
xfree(proposal[i]); |
return 0; |
xfree(proposal); |
} |
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for (i = 0; i <= n; i++) |
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if (BN_is_bit_set(dh_pub, i)) |
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bits_set++; |
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debug("bits set: %d/%d", bits_set, BN_num_bits(dh->p)); |
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/* if g==2 and bits_set==1 then computing log_g(dh_pub) is trivial */ |
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if (bits_set > 1 && (BN_cmp(dh_pub, dh->p) == -1)) |
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return 1; |
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log("invalid public DH value (%d/%d)", bits_set, BN_num_bits(dh->p)); |
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return 0; |
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} |
} |
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DH * |
static void |
dh_gen_key(DH *dh) |
kex_protocol_error(int type, int plen, void *ctxt) |
{ |
{ |
int tries = 0; |
error("Hm, kex protocol error: type %d plen %d", type, plen); |
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do { |
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if (DH_generate_key(dh) == 0) |
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fatal("DH_generate_key"); |
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if (tries++ > 10) |
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fatal("dh_new_group1: too many bad keys: giving up"); |
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} while (!dh_pub_is_valid(dh, dh->pub_key)); |
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return dh; |
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} |
} |
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DH * |
static void |
dh_new_group_asc(const char *gen, const char *modulus) |
kex_clear_dispatch(void) |
{ |
{ |
DH *dh; |
int i; |
int ret; |
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dh = DH_new(); |
/* Numbers 30-49 are used for kex packets */ |
if (dh == NULL) |
for (i = 30; i <= 49; i++) |
fatal("DH_new"); |
dispatch_set(i, &kex_protocol_error); |
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if ((ret = BN_hex2bn(&dh->p, modulus)) < 0) |
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fatal("BN_hex2bn p"); |
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if ((ret = BN_hex2bn(&dh->g, gen)) < 0) |
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fatal("BN_hex2bn g"); |
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return (dh_gen_key(dh)); |
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} |
} |
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DH * |
void |
dh_new_group(BIGNUM *gen, BIGNUM *modulus) |
kex_finish(Kex *kex) |
{ |
{ |
DH *dh; |
int plen; |
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dh = DH_new(); |
kex_clear_dispatch(); |
if (dh == NULL) |
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fatal("DH_new"); |
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dh->p = modulus; |
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dh->g = gen; |
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return (dh_gen_key(dh)); |
packet_start(SSH2_MSG_NEWKEYS); |
} |
packet_send(); |
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/* packet_write_wait(); */ |
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debug("SSH2_MSG_NEWKEYS sent"); |
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DH * |
debug("waiting for SSH2_MSG_NEWKEYS"); |
dh_new_group1() |
packet_read_expect(&plen, SSH2_MSG_NEWKEYS); |
{ |
debug("SSH2_MSG_NEWKEYS received"); |
static char *gen = "2", *group1 = |
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"FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1" |
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"29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD" |
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"EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245" |
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"E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED" |
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"EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE65381" |
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"FFFFFFFF" "FFFFFFFF"; |
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return (dh_new_group_asc(gen, group1)); |
kex->done = 1; |
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buffer_clear(&kex->peer); |
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/* buffer_clear(&kex->my); */ |
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kex->flags &= ~KEX_INIT_SENT; |
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xfree(kex->name); |
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kex->name = NULL; |
} |
} |
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void |
void |
dump_digest(unsigned char *digest, int len) |
kex_send_kexinit(Kex *kex) |
{ |
{ |
int i; |
if (kex == NULL) { |
for (i = 0; i< len; i++){ |
error("kex_send_kexinit: no kex, cannot rekey"); |
fprintf(stderr, "%02x", digest[i]); |
return; |
if(i%2!=0) |
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fprintf(stderr, " "); |
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} |
} |
fprintf(stderr, "\n"); |
if (kex->flags & KEX_INIT_SENT) { |
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debug("KEX_INIT_SENT"); |
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return; |
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} |
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kex->done = 0; |
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packet_start(SSH2_MSG_KEXINIT); |
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packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my)); |
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packet_send(); |
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debug("SSH2_MSG_KEXINIT sent"); |
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kex->flags |= KEX_INIT_SENT; |
} |
} |
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unsigned char * |
void |
kex_hash( |
kex_input_kexinit(int type, int plen, void *ctxt) |
char *client_version_string, |
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char *server_version_string, |
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char *ckexinit, int ckexinitlen, |
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char *skexinit, int skexinitlen, |
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char *serverhostkeyblob, int sbloblen, |
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BIGNUM *client_dh_pub, |
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BIGNUM *server_dh_pub, |
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BIGNUM *shared_secret) |
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{ |
{ |
Buffer b; |
char *ptr; |
static unsigned char digest[EVP_MAX_MD_SIZE]; |
int dlen; |
EVP_MD *evp_md = EVP_sha1(); |
int i; |
EVP_MD_CTX md; |
Kex *kex = (Kex *)ctxt; |
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buffer_init(&b); |
debug("SSH2_MSG_KEXINIT received"); |
buffer_put_string(&b, client_version_string, strlen(client_version_string)); |
if (kex == NULL) |
buffer_put_string(&b, server_version_string, strlen(server_version_string)); |
fatal("kex_input_kexinit: no kex, cannot rekey"); |
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/* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */ |
ptr = packet_get_raw(&dlen); |
buffer_put_int(&b, ckexinitlen+1); |
buffer_append(&kex->peer, ptr, dlen); |
buffer_put_char(&b, SSH2_MSG_KEXINIT); |
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buffer_append(&b, ckexinit, ckexinitlen); |
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buffer_put_int(&b, skexinitlen+1); |
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buffer_put_char(&b, SSH2_MSG_KEXINIT); |
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buffer_append(&b, skexinit, skexinitlen); |
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buffer_put_string(&b, serverhostkeyblob, sbloblen); |
/* discard packet */ |
buffer_put_bignum2(&b, client_dh_pub); |
for (i = 0; i < KEX_COOKIE_LEN; i++) |
buffer_put_bignum2(&b, server_dh_pub); |
packet_get_char(); |
buffer_put_bignum2(&b, shared_secret); |
for (i = 0; i < PROPOSAL_MAX; i++) |
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xfree(packet_get_string(NULL)); |
#ifdef DEBUG_KEX |
packet_get_char(); |
buffer_dump(&b); |
packet_get_int(); |
#endif |
packet_done(); |
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EVP_DigestInit(&md, evp_md); |
kex_kexinit_finish(kex); |
EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); |
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EVP_DigestFinal(&md, digest, NULL); |
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buffer_free(&b); |
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#ifdef DEBUG_KEX |
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dump_digest(digest, evp_md->md_size); |
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#endif |
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return digest; |
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} |
} |
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unsigned char * |
Kex * |
kex_hash_gex( |
kex_setup(char *proposal[PROPOSAL_MAX]) |
char *client_version_string, |
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char *server_version_string, |
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char *ckexinit, int ckexinitlen, |
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char *skexinit, int skexinitlen, |
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char *serverhostkeyblob, int sbloblen, |
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int minbits, BIGNUM *prime, BIGNUM *gen, |
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BIGNUM *client_dh_pub, |
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BIGNUM *server_dh_pub, |
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BIGNUM *shared_secret) |
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{ |
{ |
Buffer b; |
Kex *kex; |
static unsigned char digest[EVP_MAX_MD_SIZE]; |
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EVP_MD *evp_md = EVP_sha1(); |
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EVP_MD_CTX md; |
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buffer_init(&b); |
kex = xmalloc(sizeof(*kex)); |
buffer_put_string(&b, client_version_string, strlen(client_version_string)); |
memset(kex, 0, sizeof(*kex)); |
buffer_put_string(&b, server_version_string, strlen(server_version_string)); |
buffer_init(&kex->peer); |
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buffer_init(&kex->my); |
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kex_prop2buf(&kex->my, proposal); |
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kex->done = 0; |
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/* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */ |
kex_send_kexinit(kex); /* we start */ |
buffer_put_int(&b, ckexinitlen+1); |
kex_clear_dispatch(); |
buffer_put_char(&b, SSH2_MSG_KEXINIT); |
dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); |
buffer_append(&b, ckexinit, ckexinitlen); |
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buffer_put_int(&b, skexinitlen+1); |
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buffer_put_char(&b, SSH2_MSG_KEXINIT); |
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buffer_append(&b, skexinit, skexinitlen); |
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buffer_put_string(&b, serverhostkeyblob, sbloblen); |
return kex; |
buffer_put_int(&b, minbits); |
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buffer_put_bignum2(&b, prime); |
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buffer_put_bignum2(&b, gen); |
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buffer_put_bignum2(&b, client_dh_pub); |
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buffer_put_bignum2(&b, server_dh_pub); |
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buffer_put_bignum2(&b, shared_secret); |
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#ifdef DEBUG_KEX |
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buffer_dump(&b); |
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#endif |
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EVP_DigestInit(&md, evp_md); |
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EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); |
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EVP_DigestFinal(&md, digest, NULL); |
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buffer_free(&b); |
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#ifdef DEBUG_KEX |
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dump_digest(digest, evp_md->md_size); |
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#endif |
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return digest; |
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} |
} |
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unsigned char * |
static void |
derive_key(int id, int need, char unsigned *hash, BIGNUM *shared_secret) |
kex_kexinit_finish(Kex *kex) |
{ |
{ |
Buffer b; |
if (!(kex->flags & KEX_INIT_SENT)) |
EVP_MD *evp_md = EVP_sha1(); |
kex_send_kexinit(kex); |
EVP_MD_CTX md; |
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char c = id; |
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int have; |
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int mdsz = evp_md->md_size; |
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unsigned char *digest = xmalloc(((need+mdsz-1)/mdsz)*mdsz); |
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buffer_init(&b); |
kex_choose_conf(kex); |
buffer_put_bignum2(&b, shared_secret); |
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EVP_DigestInit(&md, evp_md); |
switch(kex->kex_type) { |
EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); /* shared_secret K */ |
case DH_GRP1_SHA1: |
EVP_DigestUpdate(&md, hash, mdsz); /* transport-06 */ |
kexdh(kex); |
EVP_DigestUpdate(&md, &c, 1); /* key id */ |
break; |
EVP_DigestUpdate(&md, hash, mdsz); /* session id */ |
case DH_GEX_SHA1: |
EVP_DigestFinal(&md, digest, NULL); |
kexgex(kex); |
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break; |
/* expand */ |
default: |
for (have = mdsz; need > have; have += mdsz) { |
fatal("Unsupported key exchange %d", kex->kex_type); |
EVP_DigestInit(&md, evp_md); |
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EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); |
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EVP_DigestUpdate(&md, hash, mdsz); |
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EVP_DigestUpdate(&md, digest, have); |
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EVP_DigestFinal(&md, digest + have, NULL); |
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} |
} |
buffer_free(&b); |
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#ifdef DEBUG_KEX |
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fprintf(stderr, "Digest '%c'== ", c); |
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dump_digest(digest, need); |
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#endif |
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return digest; |
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} |
} |
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#define NKEYS 6 |
static void |
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#define MAX_PROP 20 |
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#define SEP "," |
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char * |
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get_match(char *client, char *server) |
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{ |
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char *sproposals[MAX_PROP]; |
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char *c, *s, *p, *ret, *cp, *sp; |
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int i, j, nproposals; |
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c = cp = xstrdup(client); |
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s = sp = xstrdup(server); |
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for ((p = strsep(&sp, SEP)), i=0; p && *p != '\0'; |
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(p = strsep(&sp, SEP)), i++) { |
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if (i < MAX_PROP) |
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sproposals[i] = p; |
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else |
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break; |
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} |
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nproposals = i; |
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for ((p = strsep(&cp, SEP)), i=0; p && *p != '\0'; |
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(p = strsep(&cp, SEP)), i++) { |
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for (j = 0; j < nproposals; j++) { |
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if (strcmp(p, sproposals[j]) == 0) { |
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ret = xstrdup(p); |
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xfree(c); |
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xfree(s); |
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return ret; |
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} |
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} |
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} |
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xfree(c); |
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xfree(s); |
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return NULL; |
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} |
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void |
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choose_enc(Enc *enc, char *client, char *server) |
choose_enc(Enc *enc, char *client, char *server) |
{ |
{ |
char *name = get_match(client, server); |
char *name = match_list(client, server, NULL); |
if (name == NULL) |
if (name == NULL) |
fatal("no matching cipher found: client %s server %s", client, server); |
fatal("no matching cipher found: client %s server %s", client, server); |
enc->cipher = cipher_by_name(name); |
enc->cipher = cipher_by_name(name); |
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enc->iv = NULL; |
enc->iv = NULL; |
enc->key = NULL; |
enc->key = NULL; |
} |
} |
void |
static void |
choose_mac(Mac *mac, char *client, char *server) |
choose_mac(Mac *mac, char *client, char *server) |
{ |
{ |
char *name = get_match(client, server); |
char *name = match_list(client, server, NULL); |
if (name == NULL) |
if (name == NULL) |
fatal("no matching mac found: client %s server %s", client, server); |
fatal("no matching mac found: client %s server %s", client, server); |
if (strcmp(name, "hmac-md5") == 0) { |
if (mac_init(mac, name) < 0) |
mac->md = EVP_md5(); |
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} else if (strcmp(name, "hmac-sha1") == 0) { |
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mac->md = EVP_sha1(); |
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} else if (strcmp(name, "hmac-ripemd160@openssh.com") == 0) { |
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mac->md = EVP_ripemd160(); |
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} else { |
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fatal("unsupported mac %s", name); |
fatal("unsupported mac %s", name); |
} |
/* truncate the key */ |
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if (datafellows & SSH_BUG_HMAC) |
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mac->key_len = 16; |
mac->name = name; |
mac->name = name; |
mac->mac_len = mac->md->md_size; |
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mac->key_len = (datafellows & SSH_BUG_HMAC) ? 16 : mac->mac_len; |
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mac->key = NULL; |
mac->key = NULL; |
mac->enabled = 0; |
mac->enabled = 0; |
} |
} |
void |
static void |
choose_comp(Comp *comp, char *client, char *server) |
choose_comp(Comp *comp, char *client, char *server) |
{ |
{ |
char *name = get_match(client, server); |
char *name = match_list(client, server, NULL); |
if (name == NULL) |
if (name == NULL) |
fatal("no matching comp found: client %s server %s", client, server); |
fatal("no matching comp found: client %s server %s", client, server); |
if (strcmp(name, "zlib") == 0) { |
if (strcmp(name, "zlib") == 0) { |
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} |
} |
comp->name = name; |
comp->name = name; |
} |
} |
void |
static void |
choose_kex(Kex *k, char *client, char *server) |
choose_kex(Kex *k, char *client, char *server) |
{ |
{ |
k->name = get_match(client, server); |
k->name = match_list(client, server, NULL); |
if (k->name == NULL) |
if (k->name == NULL) |
fatal("no kex alg"); |
fatal("no kex alg"); |
if (strcmp(k->name, KEX_DH1) == 0) { |
if (strcmp(k->name, KEX_DH1) == 0) { |
|
|
} else |
} else |
fatal("bad kex alg %s", k->name); |
fatal("bad kex alg %s", k->name); |
} |
} |
void |
static void |
choose_hostkeyalg(Kex *k, char *client, char *server) |
choose_hostkeyalg(Kex *k, char *client, char *server) |
{ |
{ |
k->hostkeyalg = get_match(client, server); |
char *hostkeyalg = match_list(client, server, NULL); |
if (k->hostkeyalg == NULL) |
if (hostkeyalg == NULL) |
fatal("no hostkey alg"); |
fatal("no hostkey alg"); |
if (strcmp(k->hostkeyalg, KEX_DSS) != 0) |
k->hostkey_type = key_type_from_name(hostkeyalg); |
fatal("bad hostkey alg %s", k->hostkeyalg); |
if (k->hostkey_type == KEY_UNSPEC) |
|
fatal("bad hostkey alg '%s'", hostkeyalg); |
|
xfree(hostkeyalg); |
} |
} |
|
|
Kex * |
static void |
kex_choose_conf(char *cprop[PROPOSAL_MAX], char *sprop[PROPOSAL_MAX], int server) |
kex_choose_conf(Kex *kex) |
{ |
{ |
|
Newkeys *newkeys; |
|
char **my, **peer; |
|
char **cprop, **sprop; |
|
int nenc, nmac, ncomp; |
int mode; |
int mode; |
int ctos; /* direction: if true client-to-server */ |
int ctos; /* direction: if true client-to-server */ |
int need; |
int need; |
Kex *k; |
|
|
|
k = xmalloc(sizeof(*k)); |
my = kex_buf2prop(&kex->my); |
memset(k, 0, sizeof(*k)); |
peer = kex_buf2prop(&kex->peer); |
k->server = server; |
|
|
|
|
if (kex->server) { |
|
cprop=peer; |
|
sprop=my; |
|
} else { |
|
cprop=my; |
|
sprop=peer; |
|
} |
|
|
|
/* Algorithm Negotiation */ |
for (mode = 0; mode < MODE_MAX; mode++) { |
for (mode = 0; mode < MODE_MAX; mode++) { |
int nenc, nmac, ncomp; |
newkeys = xmalloc(sizeof(*newkeys)); |
ctos = (!k->server && mode == MODE_OUT) || (k->server && mode == MODE_IN); |
memset(newkeys, 0, sizeof(*newkeys)); |
|
kex->newkeys[mode] = newkeys; |
|
ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN); |
nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC; |
nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC; |
nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC; |
nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC; |
ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC; |
ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC; |
choose_enc (&k->enc [mode], cprop[nenc], sprop[nenc]); |
choose_enc (&newkeys->enc, cprop[nenc], sprop[nenc]); |
choose_mac (&k->mac [mode], cprop[nmac], sprop[nmac]); |
choose_mac (&newkeys->mac, cprop[nmac], sprop[nmac]); |
choose_comp(&k->comp[mode], cprop[ncomp], sprop[ncomp]); |
choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]); |
debug("kex: %s %s %s %s", |
debug("kex: %s %s %s %s", |
ctos ? "client->server" : "server->client", |
ctos ? "client->server" : "server->client", |
k->enc[mode].name, |
newkeys->enc.name, |
k->mac[mode].name, |
newkeys->mac.name, |
k->comp[mode].name); |
newkeys->comp.name); |
} |
} |
choose_kex(k, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]); |
choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]); |
choose_hostkeyalg(k, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS], |
choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS], |
sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]); |
sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]); |
need = 0; |
need = 0; |
for (mode = 0; mode < MODE_MAX; mode++) { |
for (mode = 0; mode < MODE_MAX; mode++) { |
if (need < k->enc[mode].cipher->key_len) |
newkeys = kex->newkeys[mode]; |
need = k->enc[mode].cipher->key_len; |
if (need < newkeys->enc.cipher->key_len) |
if (need < k->enc[mode].cipher->block_size) |
need = newkeys->enc.cipher->key_len; |
need = k->enc[mode].cipher->block_size; |
if (need < newkeys->enc.cipher->block_size) |
if (need < k->mac[mode].key_len) |
need = newkeys->enc.cipher->block_size; |
need = k->mac[mode].key_len; |
if (need < newkeys->mac.key_len) |
|
need = newkeys->mac.key_len; |
} |
} |
/* XXX need runden? */ |
/* XXX need runden? */ |
k->we_need = need; |
kex->we_need = need; |
return k; |
|
|
kex_prop_free(my); |
|
kex_prop_free(peer); |
} |
} |
|
|
int |
static u_char * |
kex_derive_keys(Kex *k, unsigned char *hash, BIGNUM *shared_secret) |
derive_key(Kex *kex, int id, int need, u_char *hash, BIGNUM *shared_secret) |
{ |
{ |
int i; |
Buffer b; |
int mode; |
EVP_MD *evp_md = EVP_sha1(); |
int ctos; |
EVP_MD_CTX md; |
unsigned char *keys[NKEYS]; |
char c = id; |
|
int have; |
|
int mdsz = evp_md->md_size; |
|
u_char *digest = xmalloc(roundup(need, mdsz)); |
|
|
|
buffer_init(&b); |
|
buffer_put_bignum2(&b, shared_secret); |
|
|
|
/* K1 = HASH(K || H || "A" || session_id) */ |
|
EVP_DigestInit(&md, evp_md); |
|
if (!(datafellows & SSH_BUG_DERIVEKEY)) |
|
EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); |
|
EVP_DigestUpdate(&md, hash, mdsz); |
|
EVP_DigestUpdate(&md, &c, 1); |
|
EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len); |
|
EVP_DigestFinal(&md, digest, NULL); |
|
|
|
/* |
|
* expand key: |
|
* Kn = HASH(K || H || K1 || K2 || ... || Kn-1) |
|
* Key = K1 || K2 || ... || Kn |
|
*/ |
|
for (have = mdsz; need > have; have += mdsz) { |
|
EVP_DigestInit(&md, evp_md); |
|
if (!(datafellows & SSH_BUG_DERIVEKEY)) |
|
EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); |
|
EVP_DigestUpdate(&md, hash, mdsz); |
|
EVP_DigestUpdate(&md, digest, have); |
|
EVP_DigestFinal(&md, digest + have, NULL); |
|
} |
|
buffer_free(&b); |
|
#ifdef DEBUG_KEX |
|
fprintf(stderr, "key '%c'== ", c); |
|
dump_digest("key", digest, need); |
|
#endif |
|
return digest; |
|
} |
|
|
|
Newkeys *current_keys[MODE_MAX]; |
|
|
|
#define NKEYS 6 |
|
void |
|
kex_derive_keys(Kex *kex, u_char *hash, BIGNUM *shared_secret) |
|
{ |
|
u_char *keys[NKEYS]; |
|
int i, mode, ctos; |
|
|
for (i = 0; i < NKEYS; i++) |
for (i = 0; i < NKEYS; i++) |
keys[i] = derive_key('A'+i, k->we_need, hash, shared_secret); |
keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, shared_secret); |
|
|
|
debug("kex_derive_keys"); |
for (mode = 0; mode < MODE_MAX; mode++) { |
for (mode = 0; mode < MODE_MAX; mode++) { |
ctos = (!k->server && mode == MODE_OUT) || (k->server && mode == MODE_IN); |
current_keys[mode] = kex->newkeys[mode]; |
k->enc[mode].iv = keys[ctos ? 0 : 1]; |
kex->newkeys[mode] = NULL; |
k->enc[mode].key = keys[ctos ? 2 : 3]; |
ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN); |
k->mac[mode].key = keys[ctos ? 4 : 5]; |
current_keys[mode]->enc.iv = keys[ctos ? 0 : 1]; |
|
current_keys[mode]->enc.key = keys[ctos ? 2 : 3]; |
|
current_keys[mode]->mac.key = keys[ctos ? 4 : 5]; |
} |
} |
return 0; |
|
} |
} |
|
|
|
Newkeys * |
|
kex_get_newkeys(int mode) |
|
{ |
|
Newkeys *ret; |
|
|
|
ret = current_keys[mode]; |
|
current_keys[mode] = NULL; |
|
return ret; |
|
} |
|
|
|
#if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) |
|
void |
|
dump_digest(char *msg, u_char *digest, int len) |
|
{ |
|
int i; |
|
|
|
fprintf(stderr, "%s\n", msg); |
|
for (i = 0; i< len; i++){ |
|
fprintf(stderr, "%02x", digest[i]); |
|
if (i%32 == 31) |
|
fprintf(stderr, "\n"); |
|
else if (i%8 == 7) |
|
fprintf(stderr, " "); |
|
} |
|
fprintf(stderr, "\n"); |
|
} |
|
#endif |