From: Daniel P. Berrange <berrange@redhat.com>
Date: Fri, 3 May 2013 13:26:56 +0000 (+0100)
Subject: Fix error handling of readdir() in virFileLoopDeviceOpen
X-Git-Tag: CVE-2013-1962~63
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1eeff53d7d2f5cdd135613d774bc09ee4ee8e8dd;p=thirdparty%2Flibvirt.git

Fix error handling of readdir() in virFileLoopDeviceOpen

To correctly handle errors from readdir() you must set 'errno'
to zero before invoking it & check its value afterwards to
distinguish error from EOF.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---

diff --git a/src/util/virfile.c b/src/util/virfile.c
index a59d67d5e1..52e2c2da00 100644
--- a/src/util/virfile.c
+++ b/src/util/virfile.c
@@ -546,6 +546,7 @@ static int virFileLoopDeviceOpen(char **dev_name)
         goto cleanup;
     }
 
+    errno = 0;
     while ((de = readdir(dh)) != NULL) {
         if (!STRPREFIX(de->d_name, "loop"))
             continue;
@@ -577,10 +578,15 @@ static int virFileLoopDeviceOpen(char **dev_name)
         /* Oh well, try the next device */
         VIR_FORCE_CLOSE(fd);
         VIR_FREE(looppath);
+        errno = 0;
     }
 
-    virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                   _("Unable to find a free loop device in /dev"));
+    if (errno != 0)
+        virReportSystemError(errno, "%s",
+                             _("Unable to iterate over loop devices"));
+    else
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Unable to find a free loop device in /dev"));
 
 cleanup:
     if (fd != -1) {