From: Andrew Morton <akpm@linux-foundation.org>
To: Kees Cook <keescook@chromium.org>
Cc: linux-kernel@vger.kernel.org,
Segher Boessenkool <segher@kernel.crashing.org>,
Thomas Gleixner <tglx@linutronix.de>,
kernel-hardening@lists.openwall.com
Subject: Re: [PATCH v2] rslib: Remove VLAs by setting upper bound on nroots
Date: Fri, 16 Mar 2018 15:59:50 -0700 [thread overview]
Message-ID: <20180316155950.35fda7c63ec59277ba504201@linux-foundation.org> (raw)
In-Reply-To: <20180315225919.GA43806@beast>
On Thu, 15 Mar 2018 15:59:19 -0700 Kees Cook <keescook@chromium.org> wrote:
> Avoid stack VLAs[1] by always allocating the upper bound of stack space
> needed. The existing users of rslib appear to max out at 24 roots[2],
> so use that as the upper bound until we have a reason to change it.
>
> Alternative considered: make init_rs() a true caller-instance and
> pre-allocate the workspaces. This would possibly need locking and
> a refactoring of the returned structure.
>
> Using kmalloc in this path doesn't look great, especially since at
> least one caller (pstore) is sensitive to allocations during rslib
> usage (it expects to run it during an Oops, for example).
Oh.
Could we allocate the storage during init_rs(), attach it to `struct
rs_control'?
next prev parent reply other threads:[~2018-03-16 22:59 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-15 22:59 Kees Cook
2018-03-16 22:38 ` Andrew Morton
2018-03-16 22:59 ` Andrew Morton [this message]
2018-03-17 6:25 ` Kees Cook
2018-03-26 23:17 ` Kees Cook
2018-03-27 23:45 ` Andrew Morton
2018-03-27 23:55 ` Kees Cook
2018-03-28 8:22 ` Thomas Gleixner
2018-03-28 10:10 ` Thomas Gleixner
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