From 8b8f1c7e9ddb2e88a144638f6527bf70e32343e3 Mon Sep 17 00:00:00 2001
From: Michael Tokarev <mjt@tls.msk.ru>
Date: Thu, 28 May 2015 14:12:26 +0300
Subject: [PATCH] slirp: use less predictable directory name in /tmp for smb
 config (CVE-2015-4037)

In this version I used mkdtemp(3) which is:

        _BSD_SOURCE
        || /* Since glibc 2.10: */
            (_POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700)

(POSIX.1-2008), so should be available on systems we care about.

While at it, reset the resulting directory name within smb structure
on error so cleanup function wont try to remove directory which we
failed to create.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
---
 net/slirp.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/net/slirp.c b/net/slirp.c
index 0e15cf6..3533837 100644
--- a/net/slirp.c
+++ b/net/slirp.c
@@ -481,7 +481,6 @@ static void slirp_smb_cleanup(SlirpState *s)
 static int slirp_smb(SlirpState* s, const char *exported_dir,
                      struct in_addr vserver_addr)
 {
-    static int instance;
     char smb_conf[128];
     char smb_cmdline[128];
     struct passwd *passwd;
@@ -505,10 +504,10 @@ static int slirp_smb(SlirpState* s, const char *exported_dir,
         return -1;
     }
 
-    snprintf(s->smb_dir, sizeof(s->smb_dir), "/tmp/qemu-smb.%ld-%d",
-             (long)getpid(), instance++);
-    if (mkdir(s->smb_dir, 0700) < 0) {
+    snprintf(s->smb_dir, sizeof(s->smb_dir), "/tmp/qemu-smb.XXXXXX");
+    if (!mkdtemp(s->smb_dir)) {
         error_report("could not create samba server dir '%s'", s->smb_dir);
+        s->smb_dir[0] = 0;
         return -1;
     }
     snprintf(smb_conf, sizeof(smb_conf), "%s/%s", s->smb_dir, "smb.conf");
-- 
2.2.1

