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Date:   Fri, 8 May 2020 22:08:24 -0700
From:   Kees Cook <keescook@chromium.org>
To:     "Eric W. Biederman" <ebiederm@xmission.com>
Cc:     linux-kernel@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Oleg Nesterov <oleg@redhat.com>, Jann Horn <jannh@google.com>,
        Greg Ungerer <gerg@linux-m68k.org>,
        Rob Landley <rob@landley.net>,
        Bernd Edlinger <bernd.edlinger@hotmail.de>,
        linux-fsdevel@vger.kernel.org, Al Viro <viro@ZenIV.linux.org.uk>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 3/6] exec: Stop open coding mutex_lock_killable of
 cred_guard_mutex
Message-ID: <202005082208.5FB101297A@keescook>
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On Fri, May 08, 2020 at 01:45:25PM -0500, Eric W. Biederman wrote:
> 
> Oleg modified the code that did
> "mutex_lock_interruptible(&current->cred_guard_mutex)" to return
> -ERESTARTNOINTR instead of -EINTR, so that userspace will never see a
> failure to grab the mutex.
> 
> Slightly earlier Liam R. Howlett defined mutex_lock_killable for
> exactly the same situation but it does it a little more cleanly.
> 
> Switch the code to mutex_lock_killable so that it is clearer what the
> code is doing.
> 
> Ref: ad776537cc6b ("Add mutex_lock_killable")
> Ref: 793285fcafce ("cred_guard_mutex: do not return -EINTR to user-space")
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook