6.5-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ 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@google.com Reported-by: Willem de Bruijn willemb@google.com Reviewed-by: Willem de Bruijn willemb@google.com Link: https://lore.kernel.org/r/20231006173355.2254983-1-edumazet@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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));