Re: [libvirt] [PATCH] xenconfig: xm: check for driver on disk format

When reviewing libxl vif typename series[0] I found out a bug

on xen-xm formatter where this "virsh domxml-to-native xen-xm file.xml"

can lead to a NULL dereference if the disk driver isn't specified. Fix this by checking for driver before writing/testing it down. [0] https://www.redhat.com/archives/libvir-list/2016-April/msg01434.html Signed-off-by: Joao Martins <joao.m.martins(a)oracle.com&gt; --- src/xenconfig/xen_xm.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/src/xenconfig/xen_xm.c b/src/xenconfig/xen_xm.c index 34d57de..3658c59 100644 --- a/src/xenconfig/xen_xm.c +++ b/src/xenconfig/xen_xm.c @@ -297,9 +297,12 @@ xenFormatXMDisk(virConfValuePtr list, type = "aio"; else type = virStorageFileFormatTypeToString(format); - virBufferAsprintf(&buf, "%s:", driver); - if (STREQ(driver, "tap")) - virBufferAsprintf(&buf, "%s:", type); + + if (driver) { + virBufferAsprintf(&buf, "%s:", driver); + if (STREQ(driver, "tap")) + virBufferAsprintf(&buf, "%s:", type); + } } else { switch (virDomainDiskGetType(disk)) { case VIR_STORAGE_TYPE_FILE: