From: Eric Dumazet edumazet@google.com
[ Upstream commit d7ea0d9df2a6265b2b180d17ebc64b38105968fc ]
I have a syzbot report that managed to get a crash in skb_checksum_help()
If syzbot can trigger these BUG(), it makes sense to replace them with more friendly WARN_ON_ONCE() since skb_checksum_help() can instead return an error code.
Note that syzbot will still crash there, until real bug is fixed.
Signed-off-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net 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 0bab2aca07fd..af52050b0f38 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3241,11 +3241,15 @@ int skb_checksum_help(struct sk_buff *skb) }
offset = skb_checksum_start_offset(skb); - BUG_ON(offset >= skb_headlen(skb)); + ret = -EINVAL; + if (WARN_ON_ONCE(offset >= skb_headlen(skb))) + goto out; + csum = skb_checksum(skb, offset, skb->len - offset, 0);
offset += skb->csum_offset; - BUG_ON(offset + sizeof(__sum16) > skb_headlen(skb)); + if (WARN_ON_ONCE(offset + sizeof(__sum16) > skb_headlen(skb))) + goto out;
ret = skb_ensure_writable(skb, offset + sizeof(__sum16)); if (ret)