[libvirt] [PATCH v2] xenconfig: fix handling of NULL disk source

[Wim Ten Have]

From: Wim ten Have <wim.ten.have at oracle.com>

It is possible to crash libvirtd when converting xl native config to
domXML when the xl config contains an empty disk source, e.g. an empty
CDROM. Fix by checking that the disk source is non-NULL before parsing it.

Signed-off-by: Wim ten Have <wim.ten.have at oracle.com>
---
 src/xenconfig/xen_xl.c                                    | 4 ++++
 tests/xlconfigdata/test-disk-positional-parms-partial.cfg | 2 +-
 tests/xlconfigdata/test-disk-positional-parms-partial.xml | 6 ++++++
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/xenconfig/xen_xl.c b/src/xenconfig/xen_xl.c
index 4f24d45..cac440c 100644
--- a/src/xenconfig/xen_xl.c
+++ b/src/xenconfig/xen_xl.c
@@ -316,6 +316,10 @@ xenParseXLDiskSrc(virDomainDiskDefPtr disk, char *srcstr)
     char *tmpstr = NULL;
     int ret = -1;
 
+    /* A NULL source is valid, e.g. an empty CDROM */
+    if (srcstr == NULL)
+        return 0;
+
     if (STRPREFIX(srcstr, "rbd:")) {
         if (!(tmpstr = virStringReplace(srcstr, "\\\\", "\\")))
             goto cleanup;
diff --git a/tests/xlconfigdata/test-disk-positional-parms-partial.cfg b/tests/xlconfigdata/test-disk-positional-parms-partial.cfg
index fd16db0..940304e 100644
--- a/tests/xlconfigdata/test-disk-positional-parms-partial.cfg
+++ b/tests/xlconfigdata/test-disk-positional-parms-partial.cfg
@@ -22,4 +22,4 @@ parallel = "none"
 serial = "none"
 builder = "hvm"
 boot = "d"
-disk = [ "/dev/HostVG/XenGuest2,,hda,,backendtype=phy", "/var/lib/libvirt/images/XenGuest2-home,,hdb,,", "/root/boot.iso,,hdc,,devtype=cdrom" ]
+disk = [ "/dev/HostVG/XenGuest2,,hda,,backendtype=phy", "/var/lib/libvirt/images/XenGuest2-home,,hdb,,", "/root/boot.iso,,hdc,,devtype=cdrom" , "format=raw,vdev=hdd,access=ro,devtype=cdrom" ]
diff --git a/tests/xlconfigdata/test-disk-positional-parms-partial.xml b/tests/xlconfigdata/test-disk-positional-parms-partial.xml
index e86a5be..52b21dc 100644
--- a/tests/xlconfigdata/test-disk-positional-parms-partial.xml
+++ b/tests/xlconfigdata/test-disk-positional-parms-partial.xml
@@ -39,6 +39,12 @@
       <readonly/>
       <address type='drive' controller='0' bus='1' target='0' unit='0'/>
     </disk>
+    <disk type='file' device='cdrom'>
+      <driver name='qemu' type='raw'/>
+      <target dev='hdd' bus='ide'/>
+      <readonly/>
+      <address type='drive' controller='0' bus='1' target='0' unit='1'/>
+    </disk>
     <controller type='ide' index='0'/>
     <interface type='bridge'>
       <mac address='00:16:3e:66:92:9c'/>
-- 
2.9.4