From 1787b9f0729d318d67cf7c5a95f0c3dba9a7cc18 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 27 Oct 2023 15:19:01 +0300 Subject: [PATCH] hsr: Prevent use after free in prp_create_tagged_frame() [ Upstream commit 876f8ab52363f649bcc74072157dfd7adfbabc0d ] The prp_fill_rct() function can fail. In that situation, it frees the skb and returns NULL. Meanwhile on the success path, it returns the original skb. So it's straight forward to fix bug by using the returned value. Fixes: 451d8123f897 ("net: prp: add packet handling support") Signed-off-by: Dan Carpenter Acked-by: Paolo Abeni Link: https://lore.kernel.org/r/57af1f28-7f57-4a96-bcd3-b7a0f2340845@moroto.mountain Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/hsr/hsr_forward.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/net/hsr/hsr_forward.c b/net/hsr/hsr_forward.c index b71dab630a87..80cdc6f6b34c 100644 --- a/net/hsr/hsr_forward.c +++ b/net/hsr/hsr_forward.c @@ -342,9 +342,7 @@ struct sk_buff *prp_create_tagged_frame(struct hsr_frame_info *frame, skb = skb_copy_expand(frame->skb_std, 0, skb_tailroom(frame->skb_std) + HSR_HLEN, GFP_ATOMIC); - prp_fill_rct(skb, frame, port); - - return skb; + return prp_fill_rct(skb, frame, port); } static void hsr_deliver_master(struct sk_buff *skb, struct net_device *dev,