linux-kernel - Re: [PATCH v2 resend] mtdchar: fix integer overflow in read/write ioctls

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Message-Id: <176112699838.140484.7478020068192325576.b4-ty@bootlin.com>
Date: Wed, 22 Oct 2025 11:56:38 +0200
From: Miquel Raynal <miquel.raynal@...tlin.com>
To: Michał Kępień <kernel@...pniu.pl>, 
 Dan Carpenter <dan.carpenter@...aro.org>
Cc: Richard Weinberger <richard@....at>, 
 Vignesh Raghavendra <vigneshr@...com>, linux-mtd@...ts.infradead.org, 
 linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH v2 resend] mtdchar: fix integer overflow in read/write
 ioctls

On Tue, 30 Sep 2025 15:32:34 +0300, Dan Carpenter wrote:
> The "req.start" and "req.len" variables are u64 values that come from the
> user at the start of the function.  We mask away the high 32 bits of
> "req.len" so that's capped at U32_MAX but the "req.start" variable can go
> up to U64_MAX which means that the addition can still integer overflow.
> 
> Use check_add_overflow() to fix this bug.
> 
> [...]

Applied to mtd/fixes, thanks!

[1/1] mtdchar: fix integer overflow in read/write ioctls
      commit: e4185bed738da755b191aa3f2e16e8b48450e1b8

Patche(s) should be available on mtd/linux.git and will be
part of the next PR (provided that no robot complains by then).

Kind regards,
Miquèl