From: Jason Gunthorpe <jgg@ziepe.ca>
To: Kees Cook <keescook@chromium.org>
Cc: Bixuan Cui <cuibixuan@linux.alibaba.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
torvalds@linux-foundation.org, leon@kernel.org,
akpm@linux-foundation.org, w@1wt.eu
Subject: Re: [PATCH -next] mm: delete oversized WARN_ON() in kvmalloc() calls
Date: Thu, 2 Dec 2021 13:03:41 -0400 [thread overview]
Message-ID: <20211202170341.GO5112@ziepe.ca> (raw)
In-Reply-To: <202112011944.28EF2FC44@keescook>
On Wed, Dec 01, 2021 at 07:46:01PM -0800, Kees Cook wrote:
> If we're rejecting the value, then it's still a pathological size, so
> shouldn't the check be happening in the caller? I think the WARN is
> doing exactly what it was supposed to do: find the places where bad
> sizes can reach vmalloc.
I think it meshes very poorly with the overflow work:
p = kzalloc(struct_size(p, regions, num_regions), GFP_KERNEL);
If num_regions is user controlled data why should the calling driver
hvae to somehow sanitize num_regions (without bugs!) instead of
relying on struct_size() and kzalloc() to contain all the sanitation?
What you are suggesting just pushes security sensitive coding into
drivers, which I think is the opposite of what we all want?
Jason
next prev parent reply other threads:[~2021-12-02 17:04 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-02 2:06 [PATCH -next] mm: delete oversized WARN_ON() in kvmalloc() calls Bixuan Cui
2021-12-02 2:53 ` Tang Yizhou
2021-12-02 3:26 ` Andrew Morton
2021-12-02 4:05 ` Bixuan Cui
2021-12-02 4:29 ` Andrew Morton
2021-12-02 10:38 ` Jeremy Sowden
2021-12-02 15:34 ` Alexei Starovoitov
2021-12-02 21:16 ` Jeremy Sowden
2021-12-02 11:49 ` Bixuan Cui
2021-12-03 19:37 ` Sean Christopherson
2021-12-02 15:23 ` Leon Romanovsky
2021-12-02 15:29 ` Matthew Wilcox
2021-12-02 16:08 ` Leon Romanovsky
2021-12-02 19:08 ` Kees Cook
2021-12-02 19:24 ` Leon Romanovsky
2021-12-02 21:23 ` Kees Cook
2021-12-02 22:03 ` Andrew Morton
2021-12-03 4:39 ` Matthew Wilcox
2021-12-02 17:00 ` Jason Gunthorpe
2021-12-02 3:46 ` Kees Cook
2021-12-02 4:44 ` Bixuan Cui
2021-12-02 17:03 ` Jason Gunthorpe [this message]
2021-12-05 11:59 ` Leon Romanovsky
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