From 305ae87dafc1a9f35374a783119d9e6001d1b8e0 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 5 Nov 2024 17:44:02 +0000 Subject: [PATCH] net: add debug check in skb_reset_network_header() Make sure (skb->data - skb->head) can fit in skb->network_header This needs CONFIG_DEBUG_NET=y. Signed-off-by: Eric Dumazet Reviewed-by: Joe Damato Reviewed-by: Xuan Zhuo Link: https://patch.msgid.link/20241105174403.850330-7-edumazet@google.com Signed-off-by: Jakub Kicinski --- include/linux/skbuff.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index f76524844e7e..f1e49a32880d 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3027,7 +3027,10 @@ static inline unsigned char *skb_network_header(const struct sk_buff *skb) static inline void skb_reset_network_header(struct sk_buff *skb) { - skb->network_header = skb->data - skb->head; + long offset = skb->data - skb->head; + + DEBUG_NET_WARN_ON_ONCE(offset != (typeof(skb->network_header))offset); + skb->network_header = offset; } static inline void skb_set_network_header(struct sk_buff *skb, const int offset)