[ovs-dev] [PATCH] ofproto-dpif: Avoid bad pointer dereference in execute_odp_actions().

[Ethan Jackson]

Looks good.

Ethan

On Thu, Oct 13, 2011 at 10:17, Ben Pfaff <blp at nicira.com> wrote:
> execute_odp_actions() can be passed a zero-length set of actions, in which
> case it may not dereference its 'odp_actions' parameter at all, but in fact
> it did do so.  In at least one corner case, odp_actions can be NULL, so
> that this caused a segfault.
>
> Introduced in commit 98403001ec "datapath: Move Netlink PID for userspace
> actions from flows to actions."
>
> Reported-by: Pravin Shelar <pshelar at nicira.com>
> ---
>  ofproto/ofproto-dpif.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
> index 36635fc..8e5a863 100644
> --- a/ofproto/ofproto-dpif.c
> +++ b/ofproto/ofproto-dpif.c
> @@ -2207,8 +2207,10 @@ execute_odp_actions(struct ofproto_dpif *ofproto, const struct flow *flow,
>     struct ofpbuf key;
>     int error;
>
> -    if (odp_actions->nla_type == OVS_ACTION_ATTR_USERSPACE
> -        && NLA_ALIGN(odp_actions->nla_len) == actions_len) {
> +    if (actions_len == 0) {
> +        return true;
> +    } else if (odp_actions->nla_type == OVS_ACTION_ATTR_USERSPACE
> +               && NLA_ALIGN(odp_actions->nla_len) == actions_len) {
>         struct user_action_cookie cookie;
>         struct dpif_upcall upcall;
>         uint64_t cookie_u64;
> --
> 1.7.4.4
>
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