Re: [libvirt] [PATCH] daemon: Fix crash in virTypedParameterArrayClear

On 2012年07月30日 19:55, Jiri Denemark wrote: > Daemon uses the following pattern when dispatching APIs with typed > parameters: > > VIR_ALLOC_N(params, nparams); > virDomain*(dom, params,&nparams, flags); > virTypedParameterArrayClear(params, nparams); > > In case nparams was originally set to 0, virDomain* API would fill it > with the number of typed parameters it can provide and we would use this > number (rather than zero) to clear params. Because VIR_ALLOC* returns > non-NULL pointer even if size is 0, the code would end up walking > through random memory. If we were lucky enough and the memory contained > 7 (VIR_TYPED_PARAM_STRING) at the right place, we would try to free a > random pointer and crash. > > Let's make sure params stays NULL when nparams is 0. > --- > daemon/remote.c | 16 ++++++++-------- > 1 file changed, 8 insertions(+), 8 deletions(-) > > diff --git a/daemon/remote.c b/daemon/remote.c > index 80626a2..d25717c 100644 > --- a/daemon/remote.c > +++ b/daemon/remote.c > @@ -989,7 +989,7 @@ remoteDispatchDomainGetSchedulerParameters(virNetServerPtr server ATTRIBUTE_UNUS > virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("nparams too large")); > goto cleanup; > } > - if (VIR_ALLOC_N(params, nparams)< 0) > + if (nparams&& VIR_ALLOC_N(params, nparams)< 0) > goto no_memory; > > if (!(dom = get_nonnull_domain(priv->conn, args->dom))) > @@ -1098,7 +1098,7 @@ remoteDispatchDomainGetSchedulerParametersFlags(virNetServerPtr server ATTRIBUTE > virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("nparams too large")); > goto cleanup; > } > - if (VIR_ALLOC_N(params, nparams)< 0) > + if (nparams&& VIR_ALLOC_N(params, nparams)< 0) Isn't nparams for these 2 APIs are guarantee positive in the APIs? virCheckPositiveArgGoto(*nparams, error);