[libvirt] [PATCH] qemu: domain: Fix potential NULL deref when parsing job private data

A specially crafted XML which would reference a non-existing disk but request the mirror to be registered with the blockjob could potentially make the parser dereference NULL. Fix it by moving the code slightly and just treat it as a wrong job XML. Found by Coverity. Reported-by: John Ferlan <jferlan@redhat.com> Signed-off-by: Peter Krempa <pkrempa@redhat.com> --- src/qemu/qemu_domain.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index 657f3ecfe4..c7eb0b5e9a 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -3012,15 +3012,19 @@ qemuDomainObjPrivateXMLParseBlockjobData(virDomainObjPtr vm, invalidData = true; } + if (mirror) { + if (disk) + job->mirrorChain = virObjectRef(disk->mirror); + else + invalidData = true; + } + job->state = state; job->newstate = newstate; job->errmsg = virXPathString("string(./errmsg)", ctxt); job->invalidData = invalidData; job->disk = disk; - if (mirror) - job->mirrorChain = virObjectRef(job->disk->mirror); - qemuDomainObjPrivateXMLParseBlockjobDataSpecific(job, ctxt, xmlopt); if (qemuBlockJobRegister(job, vm, disk, false) < 0) -- 2.21.0

On 9/2/19 10:13 AM, Peter Krempa wrote:
A specially crafted XML which would reference a non-existing disk but request the mirror to be registered with the blockjob could potentially make the parser dereference NULL. Fix it by moving the code slightly and just treat it as a wrong job XML. Found by Coverity.
Reported-by: John Ferlan <jferlan@redhat.com> Signed-off-by: Peter Krempa <pkrempa@redhat.com> --- src/qemu/qemu_domain.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
Reviewed-by: John Ferlan <jferlan@redhat.com> SFF John

On Mon, Sep 02, 2019 at 04:13:55PM +0200, Peter Krempa wrote:
A specially crafted XML which would reference a non-existing disk but request the mirror to be registered with the blockjob could potentially make the parser dereference NULL. Fix it by moving the code slightly and just treat it as a wrong job XML. Found by Coverity.
Reported-by: John Ferlan <jferlan@redhat.com> Signed-off-by: Peter Krempa <pkrempa@redhat.com> --- Reviewed-by: Erik Skultety <eskultet@redhat.com>
safe for freeze
participants (3)
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Erik Skultety
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John Ferlan
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Peter Krempa