Regression in unix stream sockets with the Smack LSM

Paul Moore paul at
Mon Sep 13 23:47:53 UTC 2021

On Mon, Sep 13, 2021 at 6:53 PM Casey Schaufler <casey at> wrote:
> Commit 77462de14a43f4d98dbd8de0f5743a4e02450b1d
>         af_unix: Add read_sock for stream socket types
> introduced a regression in UDS socket connections for the Smack LSM.
> I have not tracked done the details of why the change broke the code,
> but this is where bisecting the kernel indicates the problem lies, and
> I have verified that reverting this change repairs the problem.
> You can verify the problem with the Smack test suite:
> The failing test is tests/
> I have not looked to see if there's a similar problem with SELinux.
> There may be, but if there isn't it doesn't matter, there's still a
> bug.

FWIW, the selinux-testsuite tests ran clean today with v5.15-rc1 (it
looks like this code is only in v5.15) but as Casey said, a regression
is a regression.

Casey, what actually fails on the Smack system with this commit?

paul moore

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