From: Justin Stitt <justinstitt@google.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
Nick Desaulniers <ndesaulniers@google.com>,
Nathan Chancellor <nathan@kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Bill Wendling <morbo@google.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
llvm@lists.linux.dev, linux-hardening@vger.kernel.org
Subject: Re: [PATCH v3] fs: fix unintentional arithmetic wraparound in offset calculation
Date: Fri, 17 May 2024 13:40:59 -0700 [thread overview]
Message-ID: <CAFhGd8pQKE_uak2gqUXjbQy4LCGoJqVD2XCZrOC606u-tzS0mg@mail.gmail.com> (raw)
In-Reply-To: <ZkavMgtP2IQFGCoQ@casper.infradead.org>
Hi,
On Thu, May 16, 2024 at 6:13 PM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Fri, May 17, 2024 at 12:29:06AM +0000, Justin Stitt wrote:
> > When running syzkaller with the newly reintroduced signed integer
> > overflow sanitizer we encounter this report:
>
> why do you keep saying it's unintentional? it's clearly intended.
Right, "unintentional" is a poor choice of phrasing. I actually mean:
"overflow-checking arithmetic was done in a way that intrinsically
causes an overflow (wraparound)".
I can clearly see the intent of the code; there's even comments saying
exactly what it does: "/* Ensure offsets don't wrap. */"... So the
thinking is: let's use the overflow-checking helpers so we can get a
good signal through the sanitizers on _real_ bugs, especially in spots
with no bounds handling.
Thanks
Justin
next prev parent reply other threads:[~2024-05-17 20:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-17 0:29 [PATCH v3] fs: fix unintentional arithmetic wraparound in offset calculation Justin Stitt
2024-05-17 1:13 ` Matthew Wilcox
2024-05-17 1:26 ` Al Viro
2024-05-17 1:32 ` Matthew Wilcox
2024-05-17 21:24 ` Kees Cook
2024-05-17 20:40 ` Justin Stitt [this message]
2024-05-20 11:58 ` Jan Kara
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