From 5e021158aa22cc64da4fca1618ee0bfd2d031049 Mon Sep 17 00:00:00 2001 From: "djm@openbsd.org" Date: Fri, 16 Nov 2018 02:43:56 +0000 Subject: upstream: fix bug in HostbasedAcceptedKeyTypes and PubkeyAcceptedKeyTypes options. If only RSA-SHA2 siganture types were specified, then authentication would always fail for RSA keys as the monitor checks only the base key (not the signature algorithm) type against *AcceptedKeyTypes. bz#2746; reported by Jakub Jelen; ok dtucker OpenBSD-Commit-ID: 117bc3dc54578dbdb515a1d3732988cb5b00461b Origin: upstream, https://anongit.mindrot.org/openssh.git/commit/?id=cd9467318b56e6e93ff9575c906ff8350af9b8a2 Last-Update: 2019-02-28 Patch-Name: fix-key-type-check.patch --- monitor.c | 39 ++++++++++++++++++++++++++++++++++----- 1 file changed, 34 insertions(+), 5 deletions(-) diff --git a/monitor.c b/monitor.c index 08fddabd7..037d6d333 100644 --- a/monitor.c +++ b/monitor.c @@ -1,4 +1,4 @@ -/* $OpenBSD: monitor.c,v 1.186 2018/07/20 03:46:34 djm Exp $ */ +/* $OpenBSD: monitor.c,v 1.188 2018/11/16 02:43:56 djm Exp $ */ /* * Copyright 2002 Niels Provos * Copyright 2002 Markus Friedl @@ -892,6 +892,35 @@ mm_answer_authrole(int sock, struct sshbuf *m) return (0); } +/* + * Check that the key type appears in the supplied pattern list, ignoring + * mismatches in the signature algorithm. (Signature algorithm checks are + * performed in the unprivileged authentication code). + * Returns 1 on success, 0 otherwise. + */ +static int +key_base_type_match(const char *method, const struct sshkey *key, + const char *list) +{ + char *s, *l, *ol = xstrdup(list); + int found = 0; + + l = ol; + for ((s = strsep(&l, ",")); s && *s != '\0'; (s = strsep(&l, ","))) { + if (sshkey_type_from_name(s) == key->type) { + found = 1; + break; + } + } + if (!found) { + error("%s key type %s is not in permitted list %s", method, + sshkey_ssh_name(key), list); + } + + free(ol); + return found; +} + int mm_answer_authpassword(int sock, struct sshbuf *m) { @@ -1197,8 +1226,8 @@ mm_answer_keyallowed(int sock, struct sshbuf *m) break; if (auth2_key_already_used(authctxt, key)) break; - if (match_pattern_list(sshkey_ssh_name(key), - options.pubkey_key_types, 0) != 1) + if (!key_base_type_match(auth_method, key, + options.pubkey_key_types)) break; allowed = user_key_allowed(ssh, authctxt->pw, key, pubkey_auth_attempt, &opts); @@ -1209,8 +1238,8 @@ mm_answer_keyallowed(int sock, struct sshbuf *m) break; if (auth2_key_already_used(authctxt, key)) break; - if (match_pattern_list(sshkey_ssh_name(key), - options.hostbased_key_types, 0) != 1) + if (!key_base_type_match(auth_method, key, + options.hostbased_key_types)) break; allowed = hostbased_key_allowed(authctxt->pw, cuser, chost, key); -- cgit v1.2.3