[PATCH for-5.10] skbuff: Fix nfct leak on napi stolen

[PATCH for-5.10] skbuff: Fix nfct leak on napi stolen

[Tao Liu]

Upstream commit [0] had fixed this issue, and backported to kernel 5.10.54.
However, nf_reset_ct() added in skb_release_head_state() instead of
napi_skb_free_stolen_head(), which lead to leakage still exist in 5.10.

[0] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8550ff8d8c75416e984d9c4b082845e57e560984

Fixes: 570341f10ecc ("skbuff: Release nfct refcount on napi stolen or re-used skbs"))
Signed-off-by: Tao Liu <taoliu828@163.com>
---
 net/core/dev.c    | 1 +
 net/core/skbuff.c | 1 -
 2 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 8cbcb6a104f2..413c2a08d79d 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6111,6 +6111,7 @@ EXPORT_SYMBOL(gro_find_complete_by_type);
 
 static void napi_skb_free_stolen_head(struct sk_buff *skb)
 {
+	nf_reset_ct(skb);
 	skb_dst_drop(skb);
 	skb_ext_put(skb);
 	kmem_cache_free(skbuff_head_cache, skb);
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 668a9d0fbbc6..09cdefe5e1c8 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -659,7 +659,6 @@ static void kfree_skbmem(struct sk_buff *skb)
 
 void skb_release_head_state(struct sk_buff *skb)
 {
-	nf_reset_ct(skb);
 	skb_dst_drop(skb);
 	if (skb->destructor) {
 		WARN_ON(in_irq());
-- 
2.31.1

Re: [PATCH for-5.10] skbuff: Fix nfct leak on napi stolen

[Jakub Kicinski]

On Tue, 14 Mar 2023 20:10:17 +0800 Tao Liu wrote:
> Upstream commit [0] had fixed this issue, and backported to kernel 5.10.54.
> However, nf_reset_ct() added in skb_release_head_state() instead of
> napi_skb_free_stolen_head(), which lead to leakage still exist in 5.10.
> 
> [0] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8550ff8d8c75416e984d9c4b082845e57e560984
> 
> Fixes: 570341f10ecc ("skbuff: Release nfct refcount on napi stolen or re-used skbs"))
> Signed-off-by: Tao Liu <taoliu828@163.com>

I'm not sure Greg will spot this. Make sure you CC stable.

Re: [PATCH for-5.10] skbuff: Fix nfct leak on napi stolen

[Greg KH]

On Tue, Mar 14, 2023 at 10:43:12PM -0700, Jakub Kicinski wrote:
> On Tue, 14 Mar 2023 20:10:17 +0800 Tao Liu wrote:
> > Upstream commit [0] had fixed this issue, and backported to kernel 5.10.54.
> > However, nf_reset_ct() added in skb_release_head_state() instead of
> > napi_skb_free_stolen_head(), which lead to leakage still exist in 5.10.
> > 
> > [0] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8550ff8d8c75416e984d9c4b082845e57e560984
> > 
> > Fixes: 570341f10ecc ("skbuff: Release nfct refcount on napi stolen or re-used skbs"))
> > Signed-off-by: Tao Liu <taoliu828@163.com>
> 
> I'm not sure Greg will spot this. Make sure you CC stable.

Ah, thanks, I missed it.

I've queued this up now, Tao, nice fix, sorry for getting the backport
wrong!

greg k-h