Re: Broken userspace crypto in linux-4.1.18

["Thomas D." <whissi@whissi.de>]

Hi

Willy Tarreau wrote:
>> Is there a dependency I missed in 4.1? I don't really see anything that
>> could have gone wrong there.
> 
> Or maybe Thomas can run a bisect ?

I cannot follow. I did a bisect between 4.1.7 and 4.1.8 as I have written
in my first mail. The bad commit was:

> commit 0571ba52a19e18a1c20469454231eef681cb1310
> Author: Herbert Xu
> Date:   Wed Dec 30 11:47:53 2015 +0800
> 
>     crypto: af_alg - Disallow bind/setkey/... after accept(2)
> 
>     [ Upstream commit c840ac6af3f8713a71b4d2363419145760bd6044 ]
> 
>     Each af_alg parent socket obtained by socket(2) corresponds to a
>     tfm object once bind(2) has succeeded.  An accept(2) call on that
>     parent socket creates a context which then uses the tfm object.
> 
>     Therefore as long as any child sockets created by accept(2) exist
>     the parent socket must not be modified or freed.
> 
>     This patch guarantees this by using locks and a reference count
>     on the parent socket.  Any attempt to modify the parent socket will
>     fail with EBUSY.


bisect log:

> Bisecting: 114 revisions left to test after this (roughly 7 steps)
> [3a1e81ad84e4d880b00ecf7ad8d03b9b772ddfa7] crypto: algif_hash - Fix race condition in hash_check_key
> Bisecting: 56 revisions left to test after this (roughly 6 steps)
> [d6341753c418d3699948290d8c0b9d9dc78bd209] udf: Prevent buffer overrun with multi-byte characters
> Bisecting: 28 revisions left to test after this (roughly 5 steps)
> [13aedd784b84cb7d8a3bb835941d80e99f5c796e] dmaengine: dw: fix cyclic transfer setup
> Bisecting: 14 revisions left to test after this (roughly 4 steps)
> [664ecf4f243bac17065cd9878790d40a592e2f3d] zram/zcomp: use GFP_NOIO to allocate streams
> Bisecting: 7 revisions left to test after this (roughly 3 steps)
> [0571ba52a19e18a1c20469454231eef681cb1310] crypto: af_alg - Disallow bind/setkey/... after accept(2)
> Bisecting: 3 revisions left to test after this (roughly 2 steps)
> [2c641f5b0c8e87d43235ce39890bcc4d0c7cd2fb] memcg: only free spare array when readers are done
> Bisecting: 1 revision left to test after this (roughly 1 step)
> [0e19e24c3fe0abde8e2c5f4543616a251ccea6bf] kernel/panic.c: turn off locks debug before releasing console lock
> Bisecting: 0 revisions left to test after this (roughly 0 steps)
> [bc24ac15b0746172a8f603171352aa54abcf7c78] printk: do cond_resched() between lines while outputting to consoles
> 0571ba52a19e18a1c20469454231eef681cb1310 is the first bad commit


-Thomas