Re: [libvirt] [PATCH v3] Avoid a possible NULL pointer dereference in qemuDomainGetTLSObjects

On Wed, Sep 20, 2017 at 6:11 AM, Erik Skultety <eskultet(a)redhat.com&gt; wrote: > On Wed, Sep 20, 2017 at 05:32:29AM -0700, Ashish Mittal wrote: > > Passing a NULL value for the argument secAlias to the function > > qemuDomainGetTLSObjects would cause a segmentation fault in > > libvirtd. > > > > Changed code to not dereference a NULL secAlias. > > > > Signed-off-by: Ashish Mittal <ashmit602(a)gmail.com&gt; > > --- > > src/qemu/qemu_hotplug.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c > > index 7dd6e5f..9ecdf0a 100644 > > --- a/src/qemu/qemu_hotplug.c > > +++ b/src/qemu/qemu_hotplug.c > > @@ -1643,7 +1643,8 @@ qemuDomainGetTLSObjects(virQEMUCapsPtr qemuCaps, > > } > > > > if (qemuBuildTLSx509BackendProps(tlsCertdir, tlsListen, tlsVerify, > > - *secAlias, qemuCaps, tlsProps) < 0) > > + secAlias ? *secAlias : NULL, > qemuCaps, > > + tlsProps) < 0) > > return -1; > > > > if (!(*tlsAlias = qemuAliasTLSObjFromSrcAlias(srcAlias))) > > A few lines above this context, we check whether we have a valid reference > to > @secinfo and if so, we try to fill the @secAlias. Can we guarantee that > when > @secinfo is passed, @secAlias has been set as well? When secinfo is passed, the line marked below should guarantee that secAlias is set to not-null. if (secinfo) { if (qemuBuildSecretInfoProps(secinfo, secProps) < 0) return -1; if (!(*secAlias = qemuDomainGetSecretAESAlias(srcAlias, false))) <=== this should ensure secAlias != NULL or return -1 return -1; }