From: Jakub Kicinski <kuba@kernel.org>
Date: Thu, 30 May 2024 23:36:16 +0000 (-0700)
Subject: net: skb: add compatibility warnings to skb_shift()
X-Git-Tag: io_uring-6.11-20240722~71^2~261^2
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=99b8add01f98a8ecf498de1467e8bf13dbf02daa;p=linux-block.git

net: skb: add compatibility warnings to skb_shift()

According to current semantics we should never try to shift data
between skbs which differ on decrypted or pp_recycle status.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 466999a7515e..c8ac79851cd6 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -4139,6 +4139,9 @@ int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
 	if (skb_zcopy(tgt) || skb_zcopy(skb))
 		return 0;
 
+	DEBUG_NET_WARN_ON_ONCE(tgt->pp_recycle != skb->pp_recycle);
+	DEBUG_NET_WARN_ON_ONCE(skb_cmp_decrypted(tgt, skb));
+
 	todo = shiftlen;
 	from = 0;
 	to = skb_shinfo(tgt)->nr_frags;