File libvirt-Fix-invalid-read-in-virCgroupGetValueStr.patch of Package libvirt

From 1ad7d6faefc13ed4cde3871a8704711c858f8d7d Mon Sep 17 00:00:00 2001
Message-Id: <1ad7d6faefc13ed4cde3871a8704711c858f8d7d.1373271644.git.jdenemar@redhat.com>
From: =?UTF-8?q?J=C3=A1n=20Tomko?= <jtomko@redhat.com>
Date: Wed, 26 Jun 2013 15:43:29 +0200
Subject: [PATCH] Fix invalid read in virCgroupGetValueStr

Don't check for '\n' at the end of file if zero bytes were read.

Found by valgrind:
==404== Invalid read of size 1
==404==    at 0x529B09F: virCgroupGetValueStr (vircgroup.c:540)
==404==    by 0x529AF64: virCgroupMoveTask (vircgroup.c:1079)
==404==    by 0x1EB475: qemuSetupCgroupForEmulator (qemu_cgroup.c:1061)
==404==    by 0x1D9489: qemuProcessStart (qemu_process.c:3801)
==404==    by 0x18557E: qemuDomainObjStart (qemu_driver.c:5787)
==404==    by 0x190FA4: qemuDomainCreateWithFlags (qemu_driver.c:5839)

Introduced by 0d0b409.

https://bugzilla.redhat.com/show_bug.cgi?id=978356
(cherry picked from commit 306c49ffd56a1c72b1892d50f2a75531c62f4a1d)
---
 src/util/cgroup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/util/cgroup.c b/src/util/cgroup.c
index e057b79..69e581f 100644
--- a/src/util/cgroup.c
+++ b/src/util/cgroup.c
@@ -366,7 +366,7 @@ static int virCgroupGetValueStr(virCgroupPtr group,
         VIR_DEBUG("Failed to read %s: %m\n", keypath);
     } else {
         /* Terminated with '\n' has sometimes harmful effects to the caller */
-        if ((*value)[rc - 1] == '\n')
+        if (rc > 0 && (*value)[rc - 1] == '\n')
             (*value)[rc - 1] = '\0';
 
         rc = 0;
-- 
1.8.2.1