From: Andrew Morton <akpm@linux-foundation.org>
To: Phillip Lougher <phillip@squashfs.org.uk>
Cc: linux-kernel@vger.kernel.org, Yuejie Shi <syjcnss@gmail.com>
Subject: Re: [PATCH] Squashfs: check block offset is not negative
Date: Tue, 4 Aug 2026 13:48:38 -0700 [thread overview]
Message-ID: <20260804134838.393c5c8f7ced5aa5fc799403@linux-foundation.org> (raw)
In-Reply-To: <20260804194037.580032-1-phillip@squashfs.org.uk>
On Tue, 4 Aug 2026 20:40:37 +0100 Phillip Lougher <phillip@squashfs.org.uk> wrote:
> If a negative offset is read off disk (for example the offset into the
> decompressed fragment block), this will cause squashfs_copy_data() to
> perform an out of bounds access.
>
> Fix by checking if offset is negative, and returning 0. This matches
> existing behaviour where an offset beyond the block returns 0 bytes
> copied.
>
> Fixes: f400e12656ab ("Squashfs: cache operations")
I agree with your removal of cc:stable. "crafted image requires
CAP_SYS_ADMIN" isn't a thing we should bother backporting.
It's worth mentioning this in the changelog - let's please develop the
habit of describing the userspace-visible impact of bugs when we fix
them.
prev parent reply other threads:[~2026-08-04 20:48 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-04 19:40 Phillip Lougher
2026-08-04 20:48 ` Andrew Morton [this message]
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