linux-kernel - Re: [PATCH 06/17] kthread: cfi: disable callback pointer check with modules

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <202103111843.9456B460@keescook>
Date:   Thu, 11 Mar 2021 18:43:28 -0800
From:   Kees Cook <keescook@...omium.org>
To:     Sami Tolvanen <samitolvanen@...gle.com>
Cc:     Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Masahiro Yamada <masahiroy@...nel.org>,
        Will Deacon <will@...nel.org>, Jessica Yu <jeyu@...nel.org>,
        Arnd Bergmann <arnd@...db.de>, Tejun Heo <tj@...nel.org>,
        bpf@...r.kernel.org, linux-hardening@...r.kernel.org,
        linux-arch@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kbuild@...r.kernel.org, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 06/17] kthread: cfi: disable callback pointer check with
 modules

On Thu, Mar 11, 2021 at 04:49:08PM -0800, Sami Tolvanen wrote:
> With CONFIG_CFI_CLANG, a callback function passed to
> __kthread_queue_delayed_work from a module points to a jump table
> entry defined in the module instead of the one used in the core
> kernel, which breaks function address equality in this check:
> 
>   WARN_ON_ONCE(timer->function != kthread_delayed_work_timer_fn);
> 
> Disable the warning when CFI and modules are enabled.
> 
> Signed-off-by: Sami Tolvanen <samitolvanen@...gle.com>

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

-- 
Kees Cook