+/* $OpenBSD: kex.c,v 1.82 2009/10/24 11:13:54 andreas Exp $ */
/*
- * 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
* modification, are permitted provided that the following conditions
*/
#include "includes.h"
-RCSID("$OpenBSD: kex.c,v 1.25 2001/03/29 21:17:39 markus Exp $");
+
+#include <sys/param.h>
+
+#include <signal.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
#include <openssl/crypto.h>
-#include <openssl/bio.h>
-#include <openssl/bn.h>
-#include <openssl/pem.h>
-#include "ssh2.h"
#include "xmalloc.h"
+#include "ssh2.h"
#include "buffer.h"
-#include "bufaux.h"
#include "packet.h"
#include "compat.h"
#include "cipher.h"
-#include "kex.h"
#include "key.h"
+#include "kex.h"
#include "log.h"
#include "mac.h"
#include "match.h"
+#include "dispatch.h"
+#include "monitor.h"
+#include "roaming.h"
+
+#if OPENSSL_VERSION_NUMBER >= 0x00907000L
+# if defined(HAVE_EVP_SHA256)
+# define evp_ssh_sha256 EVP_sha256
+# else
+extern const EVP_MD *evp_ssh_sha256(void);
+# endif
+#endif
-#define KEX_COOKIE_LEN 16
+/* prototype */
+static void kex_kexinit_finish(Kex *);
+static void kex_choose_conf(Kex *);
-Buffer *
-kex_init(char *myproposal[PROPOSAL_MAX])
+/* put algorithm proposal into buffer */
+static void
+kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX])
{
- int first_kex_packet_follows = 0;
- u_char cookie[KEX_COOKIE_LEN];
- u_int32_t rand = 0;
- int i;
- Buffer *ki = xmalloc(sizeof(*ki));
- for (i = 0; i < KEX_COOKIE_LEN; i++) {
- if (i % 4 == 0)
- rand = arc4random();
- cookie[i] = rand & 0xff;
- rand >>= 8;
- }
- buffer_init(ki);
- buffer_append(ki, (char *)cookie, sizeof cookie);
+ u_int i;
+
+ buffer_clear(b);
+ /*
+ * add a dummy cookie, the cookie will be overwritten by
+ * kex_send_kexinit(), each time a kexinit is set
+ */
+ for (i = 0; i < KEX_COOKIE_LEN; i++)
+ buffer_put_char(b, 0);
for (i = 0; i < PROPOSAL_MAX; i++)
- buffer_put_cstring(ki, myproposal[i]);
- buffer_put_char(ki, first_kex_packet_follows);
- buffer_put_int(ki, 0); /* uint32 reserved */
- return ki;
+ buffer_put_cstring(b, proposal[i]);
+ buffer_put_char(b, 0); /* first_kex_packet_follows */
+ buffer_put_int(b, 0); /* uint32 reserved */
}
-/* send kexinit, parse and save reply */
-void
-kex_exchange_kexinit(
- Buffer *my_kexinit, Buffer *peer_kexint,
- char *peer_proposal[PROPOSAL_MAX])
+/* parse buffer and return algorithm proposal */
+static char **
+kex_buf2prop(Buffer *raw, int *first_kex_follows)
{
- int i;
- char *ptr;
- int plen;
-
- debug("send KEXINIT");
- packet_start(SSH2_MSG_KEXINIT);
- packet_put_raw(buffer_ptr(my_kexinit), buffer_len(my_kexinit));
- packet_send();
- packet_write_wait();
- debug("done");
+ Buffer b;
+ u_int i;
+ char **proposal;
- /*
- * read and save raw KEXINIT payload in buffer. this is used during
- * computation of the session_id and the session keys.
- */
- debug("wait KEXINIT");
- packet_read_expect(&plen, SSH2_MSG_KEXINIT);
- ptr = packet_get_raw(&plen);
- buffer_append(peer_kexint, ptr, plen);
+ proposal = xcalloc(PROPOSAL_MAX, sizeof(char *));
- /* parse packet and save algorithm proposal */
+ buffer_init(&b);
+ buffer_append(&b, buffer_ptr(raw), buffer_len(raw));
/* skip cookie */
for (i = 0; i < KEX_COOKIE_LEN; i++)
- packet_get_char();
+ buffer_get_char(&b);
/* extract kex init proposal strings */
for (i = 0; i < PROPOSAL_MAX; i++) {
- peer_proposal[i] = packet_get_string(NULL);
- debug("got kexinit: %s", peer_proposal[i]);
+ proposal[i] = buffer_get_string(&b,NULL);
+ debug2("kex_parse_kexinit: %s", proposal[i]);
}
- /* first kex follow / reserved */
- i = packet_get_char();
- debug("first kex follow: %d ", i);
- i = packet_get_int();
- debug("reserved: %d ", i);
- packet_done();
- debug("done");
+ /* first kex follows / reserved */
+ i = buffer_get_char(&b);
+ if (first_kex_follows != NULL)
+ *first_kex_follows = i;
+ debug2("kex_parse_kexinit: first_kex_follows %d ", i);
+ i = buffer_get_int(&b);
+ debug2("kex_parse_kexinit: reserved %u ", i);
+ buffer_free(&b);
+ return proposal;
}
-#ifdef DEBUG_KEX
-void
-dump_digest(u_char *digest, int len)
+static void
+kex_prop_free(char **proposal)
{
- int i;
- for (i = 0; i< len; i++){
- fprintf(stderr, "%02x", digest[i]);
- if(i%2!=0)
- fprintf(stderr, " ");
- }
- fprintf(stderr, "\n");
+ u_int i;
+
+ for (i = 0; i < PROPOSAL_MAX; i++)
+ xfree(proposal[i]);
+ xfree(proposal);
}
-#endif
-u_char *
-kex_hash(
- char *client_version_string,
- char *server_version_string,
- char *ckexinit, int ckexinitlen,
- char *skexinit, int skexinitlen,
- char *serverhostkeyblob, int sbloblen,
- BIGNUM *client_dh_pub,
- BIGNUM *server_dh_pub,
- BIGNUM *shared_secret)
+/* ARGSUSED */
+static void
+kex_protocol_error(int type, u_int32_t seq, void *ctxt)
{
- Buffer b;
- static u_char digest[EVP_MAX_MD_SIZE];
- EVP_MD *evp_md = EVP_sha1();
- EVP_MD_CTX md;
-
- buffer_init(&b);
- buffer_put_string(&b, client_version_string, strlen(client_version_string));
- buffer_put_string(&b, server_version_string, strlen(server_version_string));
-
- /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
- buffer_put_int(&b, ckexinitlen+1);
- buffer_put_char(&b, SSH2_MSG_KEXINIT);
- buffer_append(&b, ckexinit, ckexinitlen);
- buffer_put_int(&b, skexinitlen+1);
- buffer_put_char(&b, SSH2_MSG_KEXINIT);
- buffer_append(&b, skexinit, skexinitlen);
-
- buffer_put_string(&b, serverhostkeyblob, sbloblen);
- buffer_put_bignum2(&b, client_dh_pub);
- buffer_put_bignum2(&b, server_dh_pub);
- buffer_put_bignum2(&b, shared_secret);
-
-#ifdef DEBUG_KEX
- buffer_dump(&b);
-#endif
+ error("Hm, kex protocol error: type %d seq %u", type, seq);
+}
- EVP_DigestInit(&md, evp_md);
- EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
- EVP_DigestFinal(&md, digest, NULL);
+static void
+kex_reset_dispatch(void)
+{
+ dispatch_range(SSH2_MSG_TRANSPORT_MIN,
+ SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error);
+ dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
+}
- buffer_free(&b);
+void
+kex_finish(Kex *kex)
+{
+ kex_reset_dispatch();
-#ifdef DEBUG_KEX
- dump_digest(digest, evp_md->md_size);
-#endif
- return digest;
+ packet_start(SSH2_MSG_NEWKEYS);
+ packet_send();
+ /* packet_write_wait(); */
+ debug("SSH2_MSG_NEWKEYS sent");
+
+ debug("expecting SSH2_MSG_NEWKEYS");
+ packet_read_expect(SSH2_MSG_NEWKEYS);
+ packet_check_eom();
+ debug("SSH2_MSG_NEWKEYS received");
+
+ kex->done = 1;
+ buffer_clear(&kex->peer);
+ /* buffer_clear(&kex->my); */
+ kex->flags &= ~KEX_INIT_SENT;
+ xfree(kex->name);
+ kex->name = NULL;
}
-u_char *
-kex_hash_gex(
- char *client_version_string,
- char *server_version_string,
- char *ckexinit, int ckexinitlen,
- char *skexinit, int skexinitlen,
- char *serverhostkeyblob, int sbloblen,
- int min, int wantbits, int max, BIGNUM *prime, BIGNUM *gen,
- BIGNUM *client_dh_pub,
- BIGNUM *server_dh_pub,
- BIGNUM *shared_secret)
+void
+kex_send_kexinit(Kex *kex)
{
- Buffer b;
- static u_char digest[EVP_MAX_MD_SIZE];
- EVP_MD *evp_md = EVP_sha1();
- EVP_MD_CTX md;
+ u_int32_t rnd = 0;
+ u_char *cookie;
+ u_int i;
- buffer_init(&b);
- buffer_put_string(&b, client_version_string, strlen(client_version_string));
- buffer_put_string(&b, server_version_string, strlen(server_version_string));
-
- /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
- buffer_put_int(&b, ckexinitlen+1);
- buffer_put_char(&b, SSH2_MSG_KEXINIT);
- buffer_append(&b, ckexinit, ckexinitlen);
- buffer_put_int(&b, skexinitlen+1);
- buffer_put_char(&b, SSH2_MSG_KEXINIT);
- buffer_append(&b, skexinit, skexinitlen);
-
- buffer_put_string(&b, serverhostkeyblob, sbloblen);
- if (min == -1 || max == -1)
- buffer_put_int(&b, wantbits);
- else {
- buffer_put_int(&b, min);
- buffer_put_int(&b, wantbits);
- buffer_put_int(&b, max);
+ if (kex == NULL) {
+ error("kex_send_kexinit: no kex, cannot rekey");
+ return;
}
- buffer_put_bignum2(&b, prime);
- buffer_put_bignum2(&b, gen);
- buffer_put_bignum2(&b, client_dh_pub);
- buffer_put_bignum2(&b, server_dh_pub);
- buffer_put_bignum2(&b, shared_secret);
+ if (kex->flags & KEX_INIT_SENT) {
+ debug("KEX_INIT_SENT");
+ return;
+ }
+ kex->done = 0;
-#ifdef DEBUG_KEX
- buffer_dump(&b);
-#endif
+ /* generate a random cookie */
+ if (buffer_len(&kex->my) < KEX_COOKIE_LEN)
+ fatal("kex_send_kexinit: kex proposal too short");
+ cookie = buffer_ptr(&kex->my);
+ for (i = 0; i < KEX_COOKIE_LEN; i++) {
+ if (i % 4 == 0)
+ rnd = arc4random();
+ cookie[i] = rnd;
+ rnd >>= 8;
+ }
+ packet_start(SSH2_MSG_KEXINIT);
+ packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my));
+ packet_send();
+ debug("SSH2_MSG_KEXINIT sent");
+ kex->flags |= KEX_INIT_SENT;
+}
- EVP_DigestInit(&md, evp_md);
- EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
- EVP_DigestFinal(&md, digest, NULL);
+/* ARGSUSED */
+void
+kex_input_kexinit(int type, u_int32_t seq, void *ctxt)
+{
+ char *ptr;
+ u_int i, dlen;
+ Kex *kex = (Kex *)ctxt;
- buffer_free(&b);
+ debug("SSH2_MSG_KEXINIT received");
+ if (kex == NULL)
+ fatal("kex_input_kexinit: no kex, cannot rekey");
-#ifdef DEBUG_KEX
- dump_digest(digest, evp_md->md_size);
-#endif
- return digest;
+ ptr = packet_get_raw(&dlen);
+ buffer_append(&kex->peer, ptr, dlen);
+
+ /* discard packet */
+ for (i = 0; i < KEX_COOKIE_LEN; i++)
+ packet_get_char();
+ for (i = 0; i < PROPOSAL_MAX; i++)
+ xfree(packet_get_string(NULL));
+ (void) packet_get_char();
+ (void) packet_get_int();
+ packet_check_eom();
+
+ kex_kexinit_finish(kex);
}
-u_char *
-derive_key(int id, int need, u_char *hash, BIGNUM *shared_secret)
+Kex *
+kex_setup(char *proposal[PROPOSAL_MAX])
{
- Buffer b;
- EVP_MD *evp_md = EVP_sha1();
- EVP_MD_CTX md;
- char c = id;
- int have;
- int mdsz = evp_md->md_size;
- u_char *digest = xmalloc(((need+mdsz-1)/mdsz)*mdsz);
+ Kex *kex;
- buffer_init(&b);
- buffer_put_bignum2(&b, shared_secret);
+ kex = xcalloc(1, sizeof(*kex));
+ buffer_init(&kex->peer);
+ buffer_init(&kex->my);
+ kex_prop2buf(&kex->my, proposal);
+ kex->done = 0;
- EVP_DigestInit(&md, evp_md);
- EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); /* shared_secret K */
- EVP_DigestUpdate(&md, hash, mdsz); /* transport-06 */
- EVP_DigestUpdate(&md, &c, 1); /* key id */
- EVP_DigestUpdate(&md, hash, mdsz); /* session id */
- EVP_DigestFinal(&md, digest, NULL);
+ kex_send_kexinit(kex); /* we start */
+ kex_reset_dispatch();
- /* expand */
- for (have = mdsz; need > have; have += mdsz) {
- EVP_DigestInit(&md, evp_md);
- 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);
+ return kex;
+}
+
+static void
+kex_kexinit_finish(Kex *kex)
+{
+ if (!(kex->flags & KEX_INIT_SENT))
+ kex_send_kexinit(kex);
+
+ kex_choose_conf(kex);
+
+ if (kex->kex_type >= 0 && kex->kex_type < KEX_MAX &&
+ kex->kex[kex->kex_type] != NULL) {
+ (kex->kex[kex->kex_type])(kex);
+ } else {
+ fatal("Unsupported key exchange %d", kex->kex_type);
}
- buffer_free(&b);
-#ifdef DEBUG_KEX
- fprintf(stderr, "Digest '%c'== ", c);
- dump_digest(digest, need);
-#endif
- return digest;
}
-void
+static void
choose_enc(Enc *enc, char *client, char *server)
{
char *name = match_list(client, server, NULL);
if (name == NULL)
- fatal("no matching cipher found: client %s server %s", client, server);
- enc->cipher = cipher_by_name(name);
- if (enc->cipher == NULL)
+ fatal("no matching cipher found: client %s server %s",
+ client, server);
+ if ((enc->cipher = cipher_by_name(name)) == NULL)
fatal("matching cipher is not supported: %s", name);
enc->name = name;
enc->enabled = 0;
enc->iv = NULL;
enc->key = NULL;
+ enc->key_len = cipher_keylen(enc->cipher);
+ enc->block_size = cipher_blocksize(enc->cipher);
}
-void
+
+static void
choose_mac(Mac *mac, char *client, char *server)
{
char *name = match_list(client, server, NULL);
if (name == NULL)
- fatal("no matching mac found: client %s server %s", client, server);
- if (mac_init(mac, name) < 0)
+ fatal("no matching mac found: client %s server %s",
+ client, server);
+ if (mac_setup(mac, name) < 0)
fatal("unsupported mac %s", name);
/* truncate the key */
if (datafellows & SSH_BUG_HMAC)
mac->key = NULL;
mac->enabled = 0;
}
-void
+
+static void
choose_comp(Comp *comp, char *client, char *server)
{
char *name = match_list(client, server, NULL);
if (name == NULL)
fatal("no matching comp found: client %s server %s", client, server);
- if (strcmp(name, "zlib") == 0) {
- comp->type = 1;
+ if (strcmp(name, "zlib@openssh.com") == 0) {
+ comp->type = COMP_DELAYED;
+ } else if (strcmp(name, "zlib") == 0) {
+ comp->type = COMP_ZLIB;
} else if (strcmp(name, "none") == 0) {
- comp->type = 0;
+ comp->type = COMP_NONE;
} else {
fatal("unsupported comp %s", name);
}
comp->name = name;
}
-void
+
+static void
choose_kex(Kex *k, char *client, char *server)
{
k->name = match_list(client, server, NULL);
if (k->name == NULL)
- fatal("no kex alg");
+ fatal("Unable to negotiate a key exchange method");
if (strcmp(k->name, KEX_DH1) == 0) {
- k->kex_type = DH_GRP1_SHA1;
- } else if (strcmp(k->name, KEX_DHGEX) == 0) {
- k->kex_type = DH_GEX_SHA1;
+ k->kex_type = KEX_DH_GRP1_SHA1;
+ k->evp_md = EVP_sha1();
+ } else if (strcmp(k->name, KEX_DH14) == 0) {
+ k->kex_type = KEX_DH_GRP14_SHA1;
+ k->evp_md = EVP_sha1();
+ } else if (strcmp(k->name, KEX_DHGEX_SHA1) == 0) {
+ k->kex_type = KEX_DH_GEX_SHA1;
+ k->evp_md = EVP_sha1();
+#if OPENSSL_VERSION_NUMBER >= 0x00907000L
+ } else if (strcmp(k->name, KEX_DHGEX_SHA256) == 0) {
+ k->kex_type = KEX_DH_GEX_SHA256;
+ k->evp_md = evp_ssh_sha256();
+#endif
} else
fatal("bad kex alg %s", k->name);
}
-void
+
+static void
choose_hostkeyalg(Kex *k, char *client, char *server)
{
char *hostkeyalg = match_list(client, server, NULL);
xfree(hostkeyalg);
}
-Kex *
-kex_choose_conf(char *cprop[PROPOSAL_MAX], char *sprop[PROPOSAL_MAX], int server)
+static int
+proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX])
{
- int mode;
- int ctos; /* direction: if true client-to-server */
- int need;
- Kex *k;
+ static int check[] = {
+ PROPOSAL_KEX_ALGS, PROPOSAL_SERVER_HOST_KEY_ALGS, -1
+ };
+ int *idx;
+ char *p;
+
+ for (idx = &check[0]; *idx != -1; idx++) {
+ if ((p = strchr(my[*idx], ',')) != NULL)
+ *p = '\0';
+ if ((p = strchr(peer[*idx], ',')) != NULL)
+ *p = '\0';
+ if (strcmp(my[*idx], peer[*idx]) != 0) {
+ debug2("proposal mismatch: my %s peer %s",
+ my[*idx], peer[*idx]);
+ return (0);
+ }
+ }
+ debug2("proposals match");
+ return (1);
+}
- k = xmalloc(sizeof(*k));
- memset(k, 0, sizeof(*k));
- k->server = server;
+static void
+kex_choose_conf(Kex *kex)
+{
+ Newkeys *newkeys;
+ char **my, **peer;
+ char **cprop, **sprop;
+ int nenc, nmac, ncomp;
+ u_int mode, ctos, need;
+ int first_kex_follows, type;
+
+ my = kex_buf2prop(&kex->my, NULL);
+ peer = kex_buf2prop(&kex->peer, &first_kex_follows);
+
+ if (kex->server) {
+ cprop=peer;
+ sprop=my;
+ } else {
+ cprop=my;
+ sprop=peer;
+ }
+ /* Check whether server offers roaming */
+ if (!kex->server) {
+ char *roaming;
+ roaming = match_list(KEX_RESUME, peer[PROPOSAL_KEX_ALGS], NULL);
+ if (roaming) {
+ kex->roaming = 1;
+ xfree(roaming);
+ }
+ }
+
+ /* Algorithm Negotiation */
for (mode = 0; mode < MODE_MAX; mode++) {
- int nenc, nmac, ncomp;
- ctos = (!k->server && mode == MODE_OUT) || (k->server && mode == MODE_IN);
+ newkeys = xcalloc(1, 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;
nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC;
ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC;
- choose_enc (&k->enc [mode], cprop[nenc], sprop[nenc]);
- choose_mac (&k->mac [mode], cprop[nmac], sprop[nmac]);
- choose_comp(&k->comp[mode], cprop[ncomp], sprop[ncomp]);
+ choose_enc (&newkeys->enc, cprop[nenc], sprop[nenc]);
+ choose_mac (&newkeys->mac, cprop[nmac], sprop[nmac]);
+ choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]);
debug("kex: %s %s %s %s",
ctos ? "client->server" : "server->client",
- k->enc[mode].name,
- k->mac[mode].name,
- k->comp[mode].name);
+ newkeys->enc.name,
+ newkeys->mac.name,
+ newkeys->comp.name);
}
- choose_kex(k, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]);
- choose_hostkeyalg(k, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
+ choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]);
+ choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]);
need = 0;
for (mode = 0; mode < MODE_MAX; mode++) {
- if (need < k->enc[mode].cipher->key_len)
- need = k->enc[mode].cipher->key_len;
- if (need < k->enc[mode].cipher->block_size)
- need = k->enc[mode].cipher->block_size;
- if (need < k->mac[mode].key_len)
- need = k->mac[mode].key_len;
+ newkeys = kex->newkeys[mode];
+ if (need < newkeys->enc.key_len)
+ need = newkeys->enc.key_len;
+ if (need < newkeys->enc.block_size)
+ need = newkeys->enc.block_size;
+ if (need < newkeys->mac.key_len)
+ need = newkeys->mac.key_len;
}
/* XXX need runden? */
- k->we_need = need;
- return k;
+ kex->we_need = need;
+
+ /* ignore the next message if the proposals do not match */
+ if (first_kex_follows && !proposals_match(my, peer) &&
+ !(datafellows & SSH_BUG_FIRSTKEX)) {
+ type = packet_read();
+ debug2("skipping next packet (type %u)", type);
+ }
+
+ kex_prop_free(my);
+ kex_prop_free(peer);
+}
+
+static u_char *
+derive_key(Kex *kex, int id, u_int need, u_char *hash, u_int hashlen,
+ BIGNUM *shared_secret)
+{
+ Buffer b;
+ EVP_MD_CTX md;
+ char c = id;
+ u_int have;
+ int mdsz;
+ u_char *digest;
+
+ if ((mdsz = EVP_MD_size(kex->evp_md)) <= 0)
+ fatal("bad kex md size %d", mdsz);
+ digest = xmalloc(roundup(need, mdsz));
+
+ buffer_init(&b);
+ buffer_put_bignum2(&b, shared_secret);
+
+ /* K1 = HASH(K || H || "A" || session_id) */
+ EVP_DigestInit(&md, kex->evp_md);
+ if (!(datafellows & SSH_BUG_DERIVEKEY))
+ EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
+ EVP_DigestUpdate(&md, hash, hashlen);
+ 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, kex->evp_md);
+ if (!(datafellows & SSH_BUG_DERIVEKEY))
+ EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
+ EVP_DigestUpdate(&md, hash, hashlen);
+ 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
-int
-kex_derive_keys(Kex *k, u_char *hash, BIGNUM *shared_secret)
+void
+kex_derive_keys(Kex *kex, u_char *hash, u_int hashlen, BIGNUM *shared_secret)
{
- int i;
- int mode;
- int ctos;
u_char *keys[NKEYS];
+ u_int i, mode, ctos;
- for (i = 0; i < NKEYS; i++)
- keys[i] = derive_key('A'+i, k->we_need, hash, shared_secret);
+ for (i = 0; i < NKEYS; i++) {
+ keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, hashlen,
+ shared_secret);
+ }
+ debug2("kex_derive_keys");
for (mode = 0; mode < MODE_MAX; mode++) {
- ctos = (!k->server && mode == MODE_OUT) || (k->server && mode == MODE_IN);
- k->enc[mode].iv = keys[ctos ? 0 : 1];
- k->enc[mode].key = keys[ctos ? 2 : 3];
- k->mac[mode].key = keys[ctos ? 4 : 5];
+ current_keys[mode] = kex->newkeys[mode];
+ kex->newkeys[mode] = NULL;
+ ctos = (!kex->server && mode == MODE_OUT) ||
+ (kex->server && mode == MODE_IN);
+ 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;
+}
+
+void
+derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus,
+ u_int8_t cookie[8], u_int8_t id[16])
+{
+ const EVP_MD *evp_md = EVP_md5();
+ EVP_MD_CTX md;
+ u_int8_t nbuf[2048], obuf[EVP_MAX_MD_SIZE];
+ int len;
+
+ EVP_DigestInit(&md, evp_md);
+
+ len = BN_num_bytes(host_modulus);
+ if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
+ fatal("%s: bad host modulus (len %d)", __func__, len);
+ BN_bn2bin(host_modulus, nbuf);
+ EVP_DigestUpdate(&md, nbuf, len);
+
+ len = BN_num_bytes(server_modulus);
+ if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
+ fatal("%s: bad server modulus (len %d)", __func__, len);
+ BN_bn2bin(server_modulus, nbuf);
+ EVP_DigestUpdate(&md, nbuf, len);
+
+ EVP_DigestUpdate(&md, cookie, 8);
+
+ EVP_DigestFinal(&md, obuf, NULL);
+ memcpy(id, obuf, 16);
+
+ memset(nbuf, 0, sizeof(nbuf));
+ memset(obuf, 0, sizeof(obuf));
+ memset(&md, 0, sizeof(md));
+}
+
+#if defined(DEBUG_KEX) || defined(DEBUG_KEXDH)
+void
+dump_digest(char *msg, u_char *digest, int len)
+{
+ u_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
andersk / openssh.git / blobdiff