From: "Michael S. Tsirkin" <mst@redhat.com>
To: Daniil Tatianin <d-tatianin@yandex-team.ru>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: Re: [PATCH v1] drivers/vhost/vhost: fix overflow checks in vhost_overflow
Date: Wed, 7 Dec 2022 10:01:53 -0500 [thread overview]
Message-ID: <20221207100028-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20221207134631.907221-1-d-tatianin@yandex-team.ru>
On Wed, Dec 07, 2022 at 04:46:31PM +0300, Daniil Tatianin wrote:
> The if statement would erroneously check for > ULONG_MAX, which could
> never evaluate to true. Check for equality instead.
>
> Found by Linux Verification Center (linuxtesting.org) with the SVACE
> static analysis tool.
>
> Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
It can trigger on a 32 bit system. I'd also expect more analysis
of the code flow than "this can not trigger switch to a condition
that can" to accompany a patch.
> ---
> drivers/vhost/vhost.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index 40097826cff0..8df706e7bc6c 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -730,7 +730,7 @@ static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
> /* Make sure 64 bit math will not overflow. */
> static bool vhost_overflow(u64 uaddr, u64 size)
> {
> - if (uaddr > ULONG_MAX || size > ULONG_MAX)
> + if (uaddr == ULONG_MAX || size == ULONG_MAX)
> return true;
>
> if (!size)
> --
> 2.25.1
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
parent reply other threads:[~2022-12-07 15:02 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <20221207134631.907221-1-d-tatianin@yandex-team.ru>]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20221207100028-mutt-send-email-mst@kernel.org \
--to=mst@redhat.com \
--cc=d-tatianin@yandex-team.ru \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=virtualization@lists.linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).