On Thu, May 24, 2018 at 10:18 PM, David Miller <da...@davemloft.net> wrote:
> From: Willem de Bruijn <willemdebruijn.ker...@gmail.com>
> Date: Wed, 23 May 2018 14:29:52 -0400
>
>> From: Willem de Bruijn <will...@google.com>
>>
>> A precondition check in ip_recv_error triggered on an otherwise benign
>> race. Remove the warning.
>>
>> The warning triggers when passing an ipv6 socket to this ipv4 error
>> handling function. RaceFuzzer was able to trigger it due to a race
>> in setsockopt IPV6_ADDRFORM.
> ...
>> This socket option converts a v6 socket that is connected to a v4 peer
>> to an v4 socket. It updates the socket on the fly, changing fields in
>> sk as well as other structs. This is inherently non-atomic. It races
>> with the lockless udp_recvmsg path.
>>
>> No other code makes an assumption that these fields are updated
>> atomically. It is benign here, too, as ip_recv_error cares only about
>> the protocol of the skbs enqueued on the error queue, for which
>> sk_family is not a precise predictor (thanks to another isue with
>> IPV6_ADDRFORM).
>>
>> Link: http://lkml.kernel.org/r/20180518120826.ga19...@dragonet.kaist.ac.kr
>> Fixes: ("7ce875e5ecb8 ipv4: warn once on passing AF_INET6 socket to
>> ip_recv_error")
>> Reported-by: DaeRyong Jeong <threeear...@gmail.com>
>> Suggested-by: Eric Dumazet <eduma...@google.com>
>> Signed-off-by: Willem de Bruijn <will...@google.com>
>
> Applied and queued up for -stable.
>
> The SHA1_ID doesn't go inside the (" ") of the Fixes tag, I fixed
> it up this time.
Thanks David. Sorry about that.
I'll send a checkpatch.pl patch to catch such typos myself
in the future. Something like
+# Check format of Fixes line
+ if ($in_commit_log && $line =~ /^\s*fixes:/i) {
+ if ($line !~ /^fixes:\s[0-9a-f]{12,40}\s\(".*"\)$/i) {
+ WARN("BAD_FIXES",
+ "Fixes tag is not of form
\"Fixes: <12+ chars of sha1> \(\"title line\"\)");
+ }
+ }
+
though it seems that Fixes lines are expressly omitted from strict
commit style checking at the moment. I don't immediately see why.
