2022-07-24 10:07:14

by Xin Xiong

Subject: [PATCH] xfrm: fix refcount leak in __xfrm_policy_check()

The issue happens on an error path in __xfrm_policy_check(). When the
fetching process of the object `pols[1]` fails, the function simply
returns 0, forgetting to decrement the reference count of `pols[0]`,
which is incremented earlier by either xfrm_sk_policy_lookup() or
xfrm_policy_lookup(). This may result in memory leaks.

Fix it by decreasing the reference count of `pols[0]` in that path.

Fixes: 134b0fc544ba ("IPsec: propagate security module errors up from flow_cache_lookup")
Signed-off-by: Xin Xiong <[email protected]>
Signed-off-by: Xin Tan <[email protected]>
---
net/xfrm/xfrm_policy.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index f1a0bab920a5..4f8bbb825abc 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -3599,6 +3599,7 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
if (pols[1]) {
if (IS_ERR(pols[1])) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINPOLERROR);
+ xfrm_pol_put(pols[0]);
return 0;
}
pols[1]->curlft.use_time = ktime_get_real_seconds();
--
2.25.1

2022-07-29 13:27:17

by Steffen Klassert

Subject: Re: [PATCH] xfrm: fix refcount leak in __xfrm_policy_check()

On Sun, Jul 24, 2022 at 05:55:58PM +0800, Xin Xiong wrote:
> The issue happens on an error path in __xfrm_policy_check(). When the
> fetching process of the object `pols[1]` fails, the function simply
> returns 0, forgetting to decrement the reference count of `pols[0]`,
> which is incremented earlier by either xfrm_sk_policy_lookup() or
> xfrm_policy_lookup(). This may result in memory leaks.
>
> Fix it by decreasing the reference count of `pols[0]` in that path.
>
> Fixes: 134b0fc544ba ("IPsec: propagate security module errors up from flow_cache_lookup")
> Signed-off-by: Xin Xiong <[email protected]>
> Signed-off-by: Xin Tan <[email protected]>

Applied, thanks a lot Xin!