From: Kees Cook <keescook@chromium.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Maciej Rozycki <macro@orcam.me.uk>,
linux-mips@vger.kernel.org
Subject: Re: [PATCH 05/20] signal/mips: Update (_save|_restore)_fp_context to fail with -EFAULT
Date: Thu, 21 Oct 2021 09:06:50 -0700 [thread overview]
Message-ID: <202110210906.AA70D50BA@keescook> (raw)
In-Reply-To: <20211020174406.17889-5-ebiederm@xmission.com>
On Wed, Oct 20, 2021 at 12:43:51PM -0500, Eric W. Biederman wrote:
> When an instruction to save or restore a register from the stack fails
> in _save_fp_context or _restore_fp_context return with -EFAULT. This
> change was made to r2300_fpu.S[1] but it looks like it got lost with
> the introduction of EX2[2]. This is also what the other implementation
> of _save_fp_context and _restore_fp_context in r4k_fpu.S does, and
> what is needed for the callers to be able to handle the error.
>
> Furthermore calling do_exit(SIGSEGV) from bad_stack is wrong because
> it does not terminate the entire process it just terminates a single
> thread.
>
> As the changed code was the only caller of arch/mips/kernel/syscall.c:bad_stack
> remove the problematic and now unused helper function.
>
> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> Cc: Maciej Rozycki <macro@orcam.me.uk>
> Cc: linux-mips@vger.kernel.org
> [1] 35938a00ba86 ("MIPS: Fix ISA I FP sigcontext access violation handling")
> [2] f92722dc4545 ("MIPS: Correct MIPS I FP sigcontext layout")
> Fixes: f92722dc4545 ("MIPS: Correct MIPS I FP sigcontext layout")
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
next prev parent reply other threads:[~2021-10-21 16:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-20 17:32 [PATCH 00/20] exit cleanups Eric W. Biederman
2021-10-20 17:43 ` [PATCH 05/20] signal/mips: Update (_save|_restore)_fp_context to fail with -EFAULT Eric W. Biederman
2021-10-21 16:06 ` Kees Cook [this message]
2021-10-24 4:24 ` Maciej W. Rozycki
2021-10-25 20:55 ` Eric W. Biederman
2021-10-24 15:27 ` Thomas Bogendoerfer
2021-10-20 21:51 ` [PATCH 21/20] signal: Replace force_sigsegv(SIGSEGV) with force_fatal_sig(SIGSEGV) Eric W. Biederman
2021-10-21 8:09 ` Geert Uytterhoeven
2021-10-21 13:33 ` Eric W. Biederman
2021-10-21 8:32 ` Philippe Mathieu-Daudé
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