From 7abf979f6a787890f20407848a8595e3a6c8aee5 Mon Sep 17 00:00:00 2001
From: Michal Privoznik <[email protected]>
Date: Fri, 9 Oct 2020 16:16:58 +0200
Subject: [PATCH 035/108] virsocketaddr: Zero @netmask in
 virSocketAddrPrefixToNetmask()

The aim of virSocketAddrPrefixToNetmask() is to initialize passed
virSocketAddr structure based on prefix length and family.
However, it doesn't set all members in the struct which may lead
to reads of uninitialized values:

==15421== Use of uninitialised value of size 8
==15421==    at 0x50F297A: _itoa_word (in /lib64/libc-2.31.so)
==15421==    by 0x510C8FE: __vfprintf_internal (in /lib64/libc-2.31.so)
==15421==    by 0x5120295: __vsnprintf_internal (in /lib64/libc-2.31.so)
==15421==    by 0x50F8969: snprintf (in /lib64/libc-2.31.so)
==15421==    by 0x51BB602: getnameinfo (in /lib64/libc-2.31.so)
==15421==    by 0x496DEE0: virSocketAddrFormatFull (virsocketaddr.c:486)
==15421==    by 0x496DD9F: virSocketAddrFormat (virsocketaddr.c:444)
==15421==    by 0x11871F: networkDnsmasqConfContents (bridge_driver.c:1404)
==15421==    by 0x1118F5: testCompareXMLToConfFiles (networkxml2conftest.c:48)
==15421==    by 0x111BAF: testCompareXMLToConfHelper (networkxml2conftest.c:112)
==15421==    by 0x112679: virTestRun (testutils.c:142)
==15421==    by 0x111D09: mymain (networkxml2conftest.c:144)
==15421==  Uninitialised value was created by a stack allocation
==15421==    at 0x1175D2: networkDnsmasqConfContents (bridge_driver.c:1056)

All callers expect the function to initialize the structure
fully.

Signed-off-by: Michal Privoznik <[email protected]>
Reviewed-by: Laine Stump <[email protected]>
(cherry picked from commit 14506720717f2a86ab64ae3d5cdef3a4b2641b11)
---
 src/util/virsocketaddr.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/util/virsocketaddr.c b/src/util/virsocketaddr.c
index 4c9f124e88..9183687e18 100644
--- a/src/util/virsocketaddr.c
+++ b/src/util/virsocketaddr.c
@@ -1100,6 +1100,8 @@ virSocketAddrPrefixToNetmask(unsigned int prefix,
                              virSocketAddrPtr netmask,
                              int family)
 {
+    memset(netmask, 0, sizeof(*netmask));
+
     netmask->data.stor.ss_family = AF_UNSPEC; /* assume failure */
 
     if (family == AF_INET) {
@@ -1138,7 +1140,7 @@ virSocketAddrPrefixToNetmask(unsigned int prefix,
     }
 
     return 0;
- }
+}
 
 /**
  * virSocketAddrGetIPPrefix:
-- 
2.33.0