diff options
Diffstat (limited to 'clientloop.c')
| -rw-r--r-- | clientloop.c | 71 |
1 files changed, 46 insertions, 25 deletions
diff --git a/clientloop.c b/clientloop.c index 9daec13c..a4a53dd1 100644 --- a/clientloop.c +++ b/clientloop.c @@ -1,4 +1,4 @@ -/* $OpenBSD: clientloop.c,v 1.350 2020/10/11 22:12:44 djm Exp $ */ +/* $OpenBSD: clientloop.c,v 1.351 2020/10/11 22:13:37 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -1814,12 +1814,13 @@ struct hostkeys_update_ctx { /* * Keys received from the server and a flag for each indicating * whether they already exist in known_hosts. - * keys_seen is filled in by hostkeys_find() and later (for new + * keys_match is filled in by hostkeys_find() and later (for new * keys) by client_global_hostkeys_private_confirm(). */ struct sshkey **keys; - int *keys_seen; - size_t nkeys, nnew; + u_int *keys_match; /* mask of HKF_MATCH_* from hostfile.h */ + int *keys_verified; /* flag for new keys verified by server */ + size_t nkeys, nnew, nincomplete; /* total, new keys, incomplete match */ /* * Keys that are in known_hosts, but were not present in the update @@ -1844,7 +1845,8 @@ hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx) for (i = 0; i < ctx->nkeys; i++) sshkey_free(ctx->keys[i]); free(ctx->keys); - free(ctx->keys_seen); + free(ctx->keys_match); + free(ctx->keys_verified); for (i = 0; i < ctx->nold; i++) sshkey_free(ctx->old_keys[i]); free(ctx->old_keys); @@ -1900,12 +1902,12 @@ hostkeys_find(struct hostkey_foreach_line *l, void *_ctx) /* Mark off keys we've already seen for this host */ for (i = 0; i < ctx->nkeys; i++) { - if (sshkey_equal(l->key, ctx->keys[i])) { - debug3("%s: found %s key at %s:%ld", __func__, - sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum); - ctx->keys_seen[i] = 1; - return 0; - } + if (!sshkey_equal(l->key, ctx->keys[i])) + continue; + debug3("%s: found %s key at %s:%ld", __func__, + sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum); + ctx->keys_match[i] |= l->match; + return 0; } /* This line contained a key that not offered by the server */ debug3("%s: deprecated %s key at %s:%ld", __func__, @@ -1940,7 +1942,7 @@ update_known_hosts(struct hostkeys_update_ctx *ctx) struct stat sb; for (i = 0; i < ctx->nkeys; i++) { - if (ctx->keys_seen[i] != 2) + if (!ctx->keys_verified[i]) continue; if ((fp = sshkey_fingerprint(ctx->keys[i], options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) @@ -2053,10 +2055,10 @@ client_global_hostkeys_private_confirm(struct ssh *ssh, int type, /* * Expect a signature for each of the ctx->nnew private keys we * haven't seen before. They will be in the same order as the - * ctx->keys where the corresponding ctx->keys_seen[i] == 0. + * ctx->keys where the corresponding ctx->keys_match[i] == 0. */ for (ndone = i = 0; i < ctx->nkeys; i++) { - if (ctx->keys_seen[i]) + if (ctx->keys_match[i]) continue; /* Prepare data to be signed: session ID, unique string, key */ sshbuf_reset(signdata); @@ -2088,7 +2090,7 @@ client_global_hostkeys_private_confirm(struct ssh *ssh, int type, goto out; } /* Key is good. Mark it as 'seen' */ - ctx->keys_seen[i] = 2; + ctx->keys_verified[i] = 1; ndone++; } if (ndone != ctx->nnew) @@ -2141,6 +2143,7 @@ client_input_hostkeys(struct ssh *ssh) static int hostkeys_seen = 0; /* XXX use struct ssh */ extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */ struct hostkeys_update_ctx *ctx = NULL; + u_int want; if (hostkeys_seen) fatal("%s: server already sent hostkeys", __func__); @@ -2205,8 +2208,10 @@ client_input_hostkeys(struct ssh *ssh) goto out; } - if ((ctx->keys_seen = calloc(ctx->nkeys, - sizeof(*ctx->keys_seen))) == NULL) + if ((ctx->keys_match = calloc(ctx->nkeys, + sizeof(*ctx->keys_match))) == NULL || + (ctx->keys_verified = calloc(ctx->nkeys, + sizeof(*ctx->keys_verified))) == NULL) fatal("%s: calloc failed", __func__); get_hostfile_hostname_ipaddr(host, @@ -2234,21 +2239,37 @@ client_input_hostkeys(struct ssh *ssh) } /* Figure out if we have any new keys to add */ - ctx->nnew = 0; + ctx->nnew = ctx->nincomplete = 0; + want = HKF_MATCH_HOST | ( options.check_host_ip ? HKF_MATCH_IP : 0); for (i = 0; i < ctx->nkeys; i++) { - if (!ctx->keys_seen[i]) + if (ctx->keys_match[i] == 0) ctx->nnew++; + if ((ctx->keys_match[i] & want) != want) + ctx->nincomplete++; } - debug3("%s: %zu keys from server: %zu new, %zu retained. %zu to remove", - __func__, ctx->nkeys, ctx->nnew, ctx->nkeys - ctx->nnew, ctx->nold); + /* + * XXX if removing keys, check whether they appear under different + * names/addresses and refuse to proceed if they do. + */ + + debug3("%s: %zu server keys: %zu new, %zu retained, " + "%zu incomplete match. %zu to remove", __func__, ctx->nkeys, + ctx->nnew, ctx->nkeys - ctx->nnew - ctx->nincomplete, + ctx->nincomplete, ctx->nold); - if (ctx->complex_hostspec && (ctx->nnew != 0 || ctx->nold != 0)) { + if (ctx->complex_hostspec && + (ctx->nnew != 0 || ctx->nold != 0 || ctx->nincomplete != 0)) { debug("%s: manual list or wildcard host pattern found, " "skipping UserKnownHostsFile update", __func__); goto out; - } else if (ctx->nnew == 0 && ctx->nold != 0) { - /* We have some keys to remove. Just do it. */ + } else if (ctx->nnew == 0 && + (ctx->nold != 0 || ctx->nincomplete != 0)) { + /* + * We have some keys to remove or fix matching for. + * We can proceed to do this without requiring a fresh proof + * from the server. + */ update_known_hosts(ctx); } else if (ctx->nnew != 0) { /* @@ -2266,7 +2287,7 @@ client_input_hostkeys(struct ssh *ssh) if ((buf = sshbuf_new()) == NULL) fatal("%s: sshbuf_new", __func__); for (i = 0; i < ctx->nkeys; i++) { - if (ctx->keys_seen[i]) + if (ctx->keys_match[i]) continue; sshbuf_reset(buf); if ((r = sshkey_putb(ctx->keys[i], buf)) != 0) |