From: sashiko-bot@kernel.org
To: "Eric Farman" <farman@linux.ibm.com>
Cc: kvm@vger.kernel.org, "Heiko Carstens" <hca@linux.ibm.com>,
linux-s390@vger.kernel.org,
"Alexander Gordeev" <agordeev@linux.ibm.com>,
"Vasily Gorbik" <gor@linux.ibm.com>
Subject: Re: [PATCH v4 3/9] s390/vfio_ccw: fix out of bounds check on CCW array
Date: Sat, 25 Jul 2026 15:33:51 +0000 [thread overview]
Message-ID: <20260725153351.B7DB11F000E9@smtp.kernel.org> (raw)
In-Reply-To: <20260725152705.3958100-4-farman@linux.ibm.com>
> The routine ccwchain_calc_length() counts the number of channel
> command words (CCWs) that are chained together in a single channel
> program, and rejects anything larger than CCWCHAIN_LEN_MAX (256) CCWs.
>
> The loop itself is "do..while (count < 257)", and while the logic in
> is_cpa_within_range() correctly adjusts between the 0-index array of
> CCWs and the count of CCWs starting at 1, this means it would look
> at a possible 257th CCW before ending the loop and (correctly)
> returning an error.
>
> Fix this by restructuring the loop to break as soon as 256 CCWs
> (thus indexes 0-255) are examined, without looking at memory
> outside the range.
>
> Fixes: 0a19e61e6d4c ("vfio: ccw: introduce channel program interfaces")
> Cc: stable@vger.kernel.org
> Signed-off-by: Eric Farman <farman@linux.ibm.com>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260725152705.3958100-1-farman@linux.ibm.com?part=3
next prev parent reply other threads:[~2026-07-25 15:33 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-25 15:26 [PATCH v4 0/9] s390/vfio_ccw fixes Eric Farman
2026-07-25 15:26 ` [PATCH v4 1/9] s390/vfio_ccw: free all memory if cp_init() fails Eric Farman
2026-07-25 15:42 ` sashiko-bot
2026-07-25 15:26 ` [PATCH v4 2/9] s390/vfio_ccw: limit the number of channel program segments Eric Farman
2026-07-25 15:39 ` sashiko-bot
2026-07-25 15:26 ` [PATCH v4 3/9] s390/vfio_ccw: fix out of bounds check on CCW array Eric Farman
2026-07-25 15:33 ` sashiko-bot [this message]
2026-07-25 16:09 ` Matthew Rosato
2026-07-25 15:27 ` [PATCH v4 4/9] s390/vfio_ccw: ensure first IDAW remains constant Eric Farman
2026-07-25 15:44 ` sashiko-bot
2026-07-25 15:27 ` [PATCH v4 5/9] s390/vfio_ccw: calculate idal length based on idaw type Eric Farman
2026-07-25 15:34 ` sashiko-bot
2026-07-25 15:27 ` [PATCH v4 6/9] s390/vfio_ccw: ensure index for read/write regions are within range Eric Farman
2026-07-25 15:42 ` sashiko-bot
2026-07-25 16:27 ` Matthew Rosato
2026-07-25 15:27 ` [PATCH v4 7/9] s390/vfio_ccw: move cp cleanup out of not operational Eric Farman
2026-07-25 15:42 ` sashiko-bot
2026-07-25 16:39 ` Matthew Rosato
2026-07-25 15:27 ` [PATCH v4 8/9] s390/vfio_ccw: implement a channel program mutex Eric Farman
2026-07-25 15:43 ` sashiko-bot
2026-07-25 17:04 ` Matthew Rosato
2026-07-25 15:27 ` [PATCH v4 9/9] s390/vfio_ccw: implement a crw lock Eric Farman
2026-07-25 15:46 ` sashiko-bot
2026-07-25 17:03 ` Matthew Rosato
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