From: Michal Privoznik <mprivozn@redhat.com>
Date: Fri, 9 Oct 2020 14:16:58 +0000 (+0200)
Subject: virsocketaddr: Zero @netmask in virSocketAddrPrefixToNetmask()
X-Git-Tag: v6.9.0-rc1~176
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=14506720717f2a86ab64ae3d5cdef3a4b2641b11;p=thirdparty%2Flibvirt.git

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 <mprivozn@redhat.com>
Reviewed-by: Laine Stump <laine@redhat.com>
---

diff --git a/src/util/virsocketaddr.c b/src/util/virsocketaddr.c
index e0eb76ded3..65aaa632c7 100644
--- a/src/util/virsocketaddr.c
+++ b/src/util/virsocketaddr.c
@@ -1097,6 +1097,8 @@ 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) {
@@ -1135,7 +1137,7 @@ virSocketAddrPrefixToNetmask(unsigned int prefix,
     }
 
     return 0;
- }
+}
 
 /**
  * virSocketAddrGetIPPrefix: