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 e0eb76ded30b65d41a52be763eeddfd84a2ab351..65aaa632c7a347bfa7006428cef0c110e25801eb 100644 (file)
--- 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: