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, 16 insertions, 6 deletions

diff --git a/auth.c b/auth.c
index b6a440213..f7c1e7f3b 100644
--- a/auth.c
+++ b/auth.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth.c,v 1.116 2016/08/13 17:47:41 markus Exp $ */
+/* $OpenBSD: auth.c,v 1.117 2016/11/06 05:46:37 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -103,6 +103,7 @@ allowed_user(struct passwd * pw)
         struct stat st;
         const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
         u_int i;
+        int r;
 #ifdef USE_SHADOW
         struct spwd *spw = NULL;
 #endif
@@ -192,8 +193,12 @@ allowed_user(struct passwd * pw)
         /* Return false if user is listed in DenyUsers */
         if (options.num_deny_users > 0) {
                 for (i = 0; i < options.num_deny_users; i++)
-                        if (match_user(pw->pw_name, hostname, ipaddr,
-                            options.deny_users[i])) {
+                        r = match_user(pw->pw_name, hostname, ipaddr,
+                            options.deny_users[i]);
+                        if (r < 0) {
+                                fatal("Invalid DenyUsers pattern \"%.100s\"",
+                                    options.deny_users[i]);
+                        } else if (r != 1) {
                                 logit("User %.100s from %.100s not allowed "
                                     "because listed in DenyUsers",
                                     pw->pw_name, hostname);
@@ -202,10 +207,15 @@ allowed_user(struct passwd * pw)
         }
         /* Return false if AllowUsers isn't empty and user isn't listed there */
         if (options.num_allow_users > 0) {
-                for (i = 0; i < options.num_allow_users; i++)
-                        if (match_user(pw->pw_name, hostname, ipaddr,
-                            options.allow_users[i]))
+                for (i = 0; i < options.num_allow_users; i++) {
+                        r = match_user(pw->pw_name, hostname, ipaddr,
+                            options.allow_users[i]);
+                        if (r < 0) {
+                                fatal("Invalid AllowUsers pattern \"%.100s\"",
+                                    options.allow_users[i]);
+                        } else if (r == 1)
                                 break;
+                }
                 /* i < options.num_allow_users iff we break for loop */
                 if (i >= options.num_allow_users) {
                         logit("User %.100s from %.100s not allowed because "