diff options
Diffstat (limited to 'crypto/openssh/kex.c')
| -rw-r--r-- | crypto/openssh/kex.c | 67 |
1 files changed, 46 insertions, 21 deletions
diff --git a/crypto/openssh/kex.c b/crypto/openssh/kex.c index bdbf388..b070ccf 100644 --- a/crypto/openssh/kex.c +++ b/crypto/openssh/kex.c @@ -23,7 +23,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: kex.c,v 1.51 2002/06/24 14:55:38 markus Exp $"); +RCSID("$OpenBSD: kex.c,v 1.55 2003/04/01 10:31:26 markus Exp $"); #include <openssl/crypto.h> @@ -44,11 +44,6 @@ RCSID("$OpenBSD: kex.c,v 1.51 2002/06/24 14:55:38 markus Exp $"); #define KEX_COOKIE_LEN 16 -/* Use privilege separation for sshd */ -int use_privsep; -struct monitor *pmonitor; - - /* prototype */ static void kex_kexinit_finish(Kex *); static void kex_choose_conf(Kex *); @@ -74,7 +69,7 @@ kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX]) /* parse buffer and return algorithm proposal */ static char ** -kex_buf2prop(Buffer *raw) +kex_buf2prop(Buffer *raw, int *first_kex_follows) { Buffer b; int i; @@ -94,6 +89,8 @@ kex_buf2prop(Buffer *raw) } /* 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 %d ", i); @@ -135,7 +132,7 @@ kex_finish(Kex *kex) /* packet_write_wait(); */ debug("SSH2_MSG_NEWKEYS sent"); - debug("waiting for SSH2_MSG_NEWKEYS"); + debug("expecting SSH2_MSG_NEWKEYS"); packet_read_expect(SSH2_MSG_NEWKEYS); packet_check_eom(); debug("SSH2_MSG_NEWKEYS received"); @@ -235,14 +232,10 @@ kex_kexinit_finish(Kex *kex) kex_choose_conf(kex); - switch (kex->kex_type) { - case DH_GRP1_SHA1: - kexdh(kex); - break; - case DH_GEX_SHA1: - kexgex(kex); - break; - default: + 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); } } @@ -299,9 +292,9 @@ choose_kex(Kex *k, char *client, char *server) if (k->name == NULL) fatal("no kex alg"); if (strcmp(k->name, KEX_DH1) == 0) { - k->kex_type = DH_GRP1_SHA1; + k->kex_type = KEX_DH_GRP1_SHA1; } else if (strcmp(k->name, KEX_DHGEX) == 0) { - k->kex_type = DH_GEX_SHA1; + k->kex_type = KEX_DH_GEX_SHA1; } else fatal("bad kex alg %s", k->name); } @@ -317,6 +310,30 @@ choose_hostkeyalg(Kex *k, char *client, char *server) xfree(hostkeyalg); } +static int +proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX]) +{ + 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); +} + static void kex_choose_conf(Kex *kex) { @@ -327,9 +344,10 @@ kex_choose_conf(Kex *kex) int mode; int ctos; /* direction: if true client-to-server */ int need; + int first_kex_follows, type; - my = kex_buf2prop(&kex->my); - peer = kex_buf2prop(&kex->peer); + my = kex_buf2prop(&kex->my, NULL); + peer = kex_buf2prop(&kex->peer, &first_kex_follows); if (kex->server) { cprop=peer; @@ -373,6 +391,13 @@ kex_choose_conf(Kex *kex) /* XXX need runden? */ 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); } @@ -433,7 +458,7 @@ kex_derive_keys(Kex *kex, u_char *hash, BIGNUM *shared_secret) for (i = 0; i < NKEYS; i++) keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, shared_secret); - debug("kex_derive_keys"); + debug2("kex_derive_keys"); for (mode = 0; mode < MODE_MAX; mode++) { current_keys[mode] = kex->newkeys[mode]; kex->newkeys[mode] = NULL; |
