[Qemu-devel] [PATCH] slirp: use less predictable directory name in /tmp for smb config (CVE-2015-4037)

[Michael Tokarev]

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

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

so should be available on systems we care about.

Signed-off-by: Michael Tokarev <m...@tls.msk.ru>
---
 net/slirp.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/net/slirp.c b/net/slirp.c
index 9bbed74..0ad32ad 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;
@@ -505,9 +504,8 @@ 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) {
+    strcpy(s->smb_dir, "/tmp/qemu-smb.XXXXXX");
+    if (!mkdtemp(s->smb_dir)) {
         error_report("could not create samba server dir '%s'", s->smb_dir);
         return -1;
     }
-- 
2.1.4