upstream commit

Validate address ranges for AllowUser/DenyUsers at
configuration load time and refuse to accept bad ones. It was previously
possible to specify invalid CIDR address ranges (e.g. djm@127.1.2.3/55) and
these would always match.

Thanks to Laurence Parry for a detailed bug report. ok markus (for
a previous diff version)

Upstream-ID: 9dfcdd9672b06e65233ea4434c38226680d40bfb

1 files changed, 15 insertions, 6 deletions

diff --git a/match.c b/match.c
index b29a30e91..c15dcd1ef 100644
--- a/match.c
+++ b/match.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: match.c,v 1.32 2016/09/21 16:55:42 djm Exp $ */
+/* $OpenBSD: match.c,v 1.33 2016/11/06 05:46:37 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -191,11 +191,10 @@ match_host_and_ip(const char *host, const char *ipaddr,
 {
         int mhost, mip;
 
-        /* error in ipaddr match */
         if ((mip = addr_match_list(ipaddr, patterns)) == -2)
-                return -1;
-        else if (mip == -1) /* negative ip address match */
-                return 0;
+                return -1; /* error in ipaddr match */
+        else if (host == NULL || ipaddr == NULL || mip == -1)
+                return 0; /* negative ip address match, or testing pattern */
 
         /* negative hostname match */
         if ((mhost = match_hostname(host, patterns)) == -1)
@@ -207,7 +206,9 @@ match_host_and_ip(const char *host, const char *ipaddr,
 }
 
 /*
- * match user, user@host_or_ip, user@host_or_ip_list against pattern
+ * Match user, user@host_or_ip, user@host_or_ip_list against pattern.
+ * If user, host and ipaddr are all NULL then validate pattern/
+ * Returns -1 on invalid pattern, 0 on no match, 1 on match.
  */
 int
 match_user(const char *user, const char *host, const char *ipaddr,
@@ -216,6 +217,14 @@ match_user(const char *user, const char *host, const char *ipaddr,
         char *p, *pat;
         int ret;
 
+        /* test mode */
+        if (user == NULL && host == NULL && ipaddr == NULL) {
+                if ((p = strchr(pattern, '@')) != NULL &&
+                    match_host_and_ip(NULL, NULL, p + 1) < 0)
+                        return -1;
+                return 0;
+        }
+
         if ((p = strchr(pattern,'@')) == NULL)
                 return match_pattern(user, pattern);