From: Eric Dumazet Date: Tue, 5 Nov 2024 17:44:03 +0000 (+0000) Subject: net: add debug check in skb_reset_mac_header() X-Git-Tag: v6.13-rc1~135^2~120^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3b6167e9bfc9eae4edad065c166c667f9a8e693a;p=thirdparty%2Fkernel%2Flinux.git net: add debug check in skb_reset_mac_header() Make sure (skb->data - skb->head) can fit in skb->mac_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/20241105174403.850330-8-edumazet@google.com Signed-off-by: Jakub Kicinski --- diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index f1e49a32880df..e5095d75abba1 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3063,7 +3063,10 @@ static inline void skb_unset_mac_header(struct sk_buff *skb) static inline void skb_reset_mac_header(struct sk_buff *skb) { - skb->mac_header = skb->data - skb->head; + long offset = skb->data - skb->head; + + DEBUG_NET_WARN_ON_ONCE(offset != (typeof(skb->mac_header))offset); + skb->mac_header = offset; } static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)