- djm@cvs.openbsd.org 2008/06/13 04:40:22

     [auth2-pubkey.c auth-rhosts.c]
     refuse to read ~/.shosts or ~/.ssh/authorized_keys that are not
     regular files; report from Solar Designer via Colin Watson in bz#1471
     ok dtucker@ deraadt@

1 files changed, 23 insertions, 9 deletions

diff --git a/auth2-pubkey.c b/auth2-pubkey.c
index 9863cd9e6..7f7ddd8cf 100644
--- a/auth2-pubkey.c
+++ b/auth2-pubkey.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2-pubkey.c,v 1.15 2006/08/03 03:34:41 deraadt Exp $ */
+/* $OpenBSD: auth2-pubkey.c,v 1.16 2008/06/13 04:40:22 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -28,6 +28,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 
+#include <fcntl.h>
 #include <pwd.h>
 #include <stdio.h>
 #include <stdarg.h>
@@ -180,7 +181,7 @@ static int
 user_key_allowed2(struct passwd *pw, Key *key, char *file)
 {
         char line[SSH_MAX_PUBKEY_BYTES];
-        int found_key = 0;
+        int found_key = 0, fd;
         FILE *f;
         u_long linenum = 0;
         struct stat st;
@@ -192,16 +193,29 @@ user_key_allowed2(struct passwd *pw, Key *key, char *file)
 
         debug("trying public key file %s", file);
 
-        /* Fail quietly if file does not exist */
-        if (stat(file, &st) < 0) {
-                /* Restore the privileged uid. */
+        /*
+         * Open the file containing the authorized keys
+         * Fail quietly if file does not exist
+         */
+        if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) {
                 restore_uid();
                 return 0;
         }
-        /* Open the file containing the authorized keys. */
-        f = fopen(file, "r");
-        if (!f) {
-                /* Restore the privileged uid. */
+        if (fstat(fd, &st) < 0) {
+                close(fd);
+                restore_uid();
+                return 0;
+        }
+        if (!S_ISREG(st.st_mode)) {
+                logit("User %s authorized keys %s is not a regular file",
+                    pw->pw_name, file);
+                close(fd);
+                restore_uid();
+                return 0;
+        }
+        unset_nonblock(fd);
+        if ((f = fdopen(fd, "r")) == NULL) {
+                close(fd);
                 restore_uid();
                 return 0;
         }