File libvirt-pci-initialize-virtual_functions-array-pointer-to-avoid-segfault.patch of Package libvirt

From a4e78f7d8d276dc97720a280027952899f5ca429 Mon Sep 17 00:00:00 2001
Message-Id: <a4e78f7d8d276dc97720a280027952899f5ca429.1373271644.git.jdenemar@redhat.com>
From: Laine Stump <laine@laine.org>
Date: Tue, 2 Jul 2013 03:58:49 -0400
Subject: [PATCH] pci: initialize virtual_functions array pointer to avoid
 segfault

This fixes https://bugzilla.redhat.com/show_bug.cgi?id=980339

The problem was that if virPCIGetVirtualFunctions was given the name
of a non-existent interface, it would return to its caller without
initializing the pointer to the array of virtual functions to NULL,
and the caller (virNetDevGetVirtualFunctions) would try to VIR_FREE()
the invalid pointer.

The final error message before the crash would be:

 virPCIGetVirtualFunctions:2088 :
  Failed to open dir '/sys/class/net/eth2/device':
  No such file or directory

In this patch I move the initialization in virPCIGetVirtualFunctions()
to the begining of the function, and also do an explicit
initialization in virNetDevGetVirtualFunctions, just in case someone
in the future adds code into that function prior to the call to
virPCIGetVirtualFunctions.
(cherry picked from commit 2c2525ab6a6f0ad5d75a6c60711e2e28cb1cebe9)
---
 src/util/pci.c       | 5 +++--
 src/util/virnetdev.c | 3 +++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/util/pci.c b/src/util/pci.c
index 129c01a..a3c1df7 100644
--- a/src/util/pci.c
+++ b/src/util/pci.c
@@ -1997,6 +1997,9 @@ pciGetVirtualFunctions(const char *sysfs_path,
     VIR_DEBUG("Attempting to get SR IOV virtual functions for device"
               "with sysfs path '%s'", sysfs_path);
 
+    *virtual_functions = NULL;
+    *num_virtual_functions = 0;
+
     dir = opendir(sysfs_path);
     if (dir == NULL) {
         memset(errbuf, '\0', sizeof(errbuf));
@@ -2007,8 +2010,6 @@ pciGetVirtualFunctions(const char *sysfs_path,
         return ret;
     }
 
-    *virtual_functions = NULL;
-    *num_virtual_functions = 0;
     while ((entry = readdir(dir))) {
         if (STRPREFIX(entry->d_name, "virtfn")) {
 
diff --git a/src/util/virnetdev.c b/src/util/virnetdev.c
index f6f1794..76db9db 100644
--- a/src/util/virnetdev.c
+++ b/src/util/virnetdev.c
@@ -988,6 +988,9 @@ virNetDevGetVirtualFunctions(const char *pfname,
     char *pci_sysfs_device_link = NULL;
     char *pciConfigAddr;
 
+    *virt_fns = NULL;
+    *n_vfname = 0;
+
     if (virNetDevSysfsFile(&pf_sysfs_device_link, pfname, "device") < 0)
         return ret;
 
-- 
1.8.2.1