Re: [libvirt] [PATCH] virConfSaveValue: protect against a NULL pointer reference

From: Wim ten Have <wim.ten.have(a)oracle.com&gt;

Fix xlconfigtest runs build for --enable-test-oom on Xen XL-2-XML Parse channel-pty Program received signal SIGSEGV, Segmentation fault. #0 0x00007ffff3c2b373 in __strchr_sse2 () from /lib64/libc.so.6 ==> #1 0x00007ffff7875701 in virConfSaveValue (buf=buf@entry=0x7fffffffd8a0, val=val@entry=0x674750) at util/virconf.c:290 #2 0x00007ffff7875668 in virConfSaveValue (buf=buf@entry=0x7fffffffd8a0, val=<optimized out>) at util/virconf.c:306 #3 0x00007ffff78757ef in virConfSaveEntry (buf=buf@entry=0x7fffffffd8a0, cur=cur@entry=0x674780) at util/virconf.c:338 #4 0x00007ffff78783eb in virConfWriteMem (memory=0x665570 "", len=len@entry=0x7fffffffd910, conf=conf@entry=0x65b940) at util/virconf.c:1543 #5 0x000000000040eccb in testCompareParseXML (replaceVars=<optimized out>, xml=<optimized out>, xlcfg=0x662c00 "/home/wtenhave/WORK/libvirt/OOMtesting/libvirt-devel/tests/xlconfigdata/test-channel-pty.cfg") at xlconfigtest.c:108 #6 testCompareHelper (data=<optimized out>) at xlconfigtest.c:205 #7 0x0000000000410b3a in virTestRun (title=title@entry=0x432cc0 "Xen XL-2-XML Parse channel-pty", body=body@entry=0x40e9b0 <testCompareHelper>, data=data@entry=0x7fffffffd9f0) at testutils.c:247 #8 0x000000000040f322 in mymain () at xlconfigtest.c:278 #9 0x0000000000411410 in virTestMain (argc=1, argv=0x7fffffffdba8, func=0x40f660 <mymain>) at testutils.c:992 #10 0x00007ffff3bc0401 in __libc_start_main () from /lib64/libc.so.6 #11 0x000000000040e86a in _start () (gdb) frame 1 #1 0x00007ffff7875701 in virConfSaveValue (buf=buf@entry=0x7fffffffd8a0, val=val@entry=0x674750) at util/virconf.c:290 290 if (strchr(val->str, '\n') != NULL) { (gdb) print *val $1 = {type = VIR_CONF_STRING, next = 0x0, l = 0, str = 0x0, list = 0x0} Signed-off-by: Wim ten Have <wim.ten.have(a)oracle.com&gt; --- src/util/virconf.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/src/util/virconf.c b/src/util/virconf.c index a85a307..9840ca6 100644 --- a/src/util/virconf.c +++ b/src/util/virconf.c @@ -287,14 +287,16 @@ virConfSaveValue(virBufferPtr buf, virConfValuePtr val) virBufferAsprintf(buf, "%llu", val->l); break; case VIR_CONF_STRING: - if (strchr(val->str, '\n') != NULL) { - virBufferAsprintf(buf, "\"\"\"%s\"\"\"", val->str); - } else if (strchr(val->str, '"') == NULL) { - virBufferAsprintf(buf, "\"%s\"", val->str); - } else if (strchr(val->str, '\'') == NULL) { - virBufferAsprintf(buf, "'%s'", val->str); - } else { - virBufferAsprintf(buf, "\"\"\"%s\"\"\"", val->str); + if (val->str) { + if (strchr(val->str, '\n') != NULL) { + virBufferAsprintf(buf, "\"\"\"%s\"\"\"", val->str); + } else if (strchr(val->str, '"') == NULL) { + virBufferAsprintf(buf, "\"%s\"", val->str); + } else if (strchr(val->str, '\'') == NULL) { + virBufferAsprintf(buf, "'%s'", val->str); + } else { + virBufferAsprintf(buf, "\"\"\"%s\"\"\"", val->str); + }