Re: [Libvir] [patch 1/5] iptables: fix invalid free
On Wed, 2007-03-21 at 09:03 -0400, Daniel Veillard wrote:
On Wed, Mar 21, 2007 at 12:47:58PM +0000, Mark McLoughlin wrote:
> In iptablesContextNew(), make sure we don't try and free an invalid
> pointer if one of the iptRulesNew() fails.
>
> Signed-off-by: Mark McLoughlin <markmc(a)redhat.com>
>
> Index: libvirt/qemud/iptables.c
> ===================================================================
> --- libvirt.orig/qemud/iptables.c
> +++ libvirt/qemud/iptables.c
> @@ -496,7 +496,7 @@ iptablesContextNew(void)
> {
> iptablesContext *ctx;
>
> - if (!(ctx = (iptablesContext *) malloc(sizeof (iptablesContext))))
> + if (!(ctx = (iptablesContext *) calloc(1, sizeof (iptablesContext))))
> return NULL;
>
> if (!(ctx->input_filter = iptRulesNew("filter", IPTABLES_PREFIX
"INPUT")))
I usually prefer malloc + memset( , 0, ) , but this probably comes from
libxml2 where I replaced malloc calls with specific wrappers (and I still
have a TODO for this in libvirt though some part of libvirt are not linked to
libxml2 I guess so that may make things a bit harder)
If libvirt was going to have it's own malloc() wrapper, I'd suggest
that the wrapper should always zero out the allocated memory. Then we
could just replace the calloc() with the wrapper.
Don't know why we'd use the libxml2 wrappers instead of our own?
What's the policy w.r.t. error reporting in qemud and libvirt
related daemons
in general ? I guess a failure to malloc or thisd kind of problems should be
logged somewhere, right ?
Yep. In this case it would be logged either to syslog if the daemon was
autostarting the network or returned to the user in the case where the
user is manually starting network.
Thanks,
Mark.