diff options
| -rw-r--r-- | usr.bin/ssh/kex.c | 41 |
1 files changed, 37 insertions, 4 deletions
diff --git a/usr.bin/ssh/kex.c b/usr.bin/ssh/kex.c index 113663598ef..0a861fb976c 100644 --- a/usr.bin/ssh/kex.c +++ b/usr.bin/ssh/kex.c @@ -23,7 +23,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: kex.c,v 1.52 2002/11/21 22:45:31 markus Exp $"); +RCSID("$OpenBSD: kex.c,v 1.53 2003/02/02 10:56:08 markus Exp $"); #include <openssl/crypto.h> @@ -74,7 +74,7 @@ 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 +94,8 @@ 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); @@ -317,6 +319,30 @@ 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 +353,10 @@ 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 +400,12 @@ 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)) { + type = packet_read(); + debug2("skipping next packet (type %u)", type); + } + kex_prop_free(my); kex_prop_free(peer); } |