6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 26c29961b142444cd99361644c30fa1e9b3da6be ]
syzbot uses panic_on_warn.
This means that the skb_dump() I added in the blamed commit are
not even called.
Rewrite this so that we get the needed skb dump before syzbot crashes.
Fixes: eeee4b77dc52 ("net: add more debug info in skb_checksum_help()")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reported-by: Willem de Bruijn <willemb@xxxxxxxxxx>
Reviewed-by: Willem de Bruijn <willemb@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20231006173355.2254983-1-edumazet@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/core/dev.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index 69a3e544676c4..968be1c20ca1f 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3285,15 +3285,19 @@ int skb_checksum_help(struct sk_buff *skb)
offset = skb_checksum_start_offset(skb);
ret = -EINVAL;
- if (WARN_ON_ONCE(offset >= skb_headlen(skb))) {
+ if (unlikely(offset >= skb_headlen(skb))) {
DO_ONCE_LITE(skb_dump, KERN_ERR, skb, false);
+ WARN_ONCE(true, "offset (%d) >= skb_headlen() (%u)\n",
+ offset, skb_headlen(skb));
goto out;
}
csum = skb_checksum(skb, offset, skb->len - offset, 0);
offset += skb->csum_offset;
- if (WARN_ON_ONCE(offset + sizeof(__sum16) > skb_headlen(skb))) {
+ if (unlikely(offset + sizeof(__sum16) > skb_headlen(skb))) {
DO_ONCE_LITE(skb_dump, KERN_ERR, skb, false);
+ WARN_ONCE(true, "offset+2 (%zu) > skb_headlen() (%u)\n",
+ offset + sizeof(__sum16), skb_headlen(skb));
goto out;
}
ret = skb_ensure_writable(skb, offset + sizeof(__sum16));
--
2.40.1
