[TC]: oops in em_meta

If userspace passes a unknown match index into em_meta, then
em_meta_change will return an error and the data for the match will
not be set. This then causes an null pointer dereference when the
cleanup is done in the error path via tcf_em_tree_destroy. Since the
tree structure comes kzalloc, it is initialized to NULL.

Discovered when testing a new version of tc command against an
accidental older kernel.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Stephen Hemminger 2008-02-07 18:13:00 -08:00 committed by David S. Miller
parent 4e881a217b
commit 04f217aca4
1 changed files with 6 additions and 4 deletions

View File

@ -735,11 +735,13 @@ static int em_meta_match(struct sk_buff *skb, struct tcf_ematch *m,
static inline void meta_delete(struct meta_match *meta)
{
struct meta_type_ops *ops = meta_type_ops(&meta->lvalue);
if (meta) {
struct meta_type_ops *ops = meta_type_ops(&meta->lvalue);
if (ops && ops->destroy) {
ops->destroy(&meta->lvalue);
ops->destroy(&meta->rvalue);
if (ops && ops->destroy) {
ops->destroy(&meta->lvalue);
ops->destroy(&meta->rvalue);
}
}
kfree(meta);