linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Xie Yongji <xieyongji@bytedance.com>
To: mst@redhat.com, jasowang@redhat.com, dan.carpenter@oracle.com
Cc: virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2 2/2] vhost: Fix the calculation in vhost_overflow()
Date: Wed, 28 Jul 2021 21:07:56 +0800	[thread overview]
Message-ID: <20210728130756.97-2-xieyongji@bytedance.com> (raw)
In-Reply-To: <20210728130756.97-1-xieyongji@bytedance.com>

This fixes the incorrect calculation for integer overflow
when the last address of iova range is 0xffffffff.

Fixes: ec33d031a14b ("vhost: detect 32 bit integer wrap around“)
Reported-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/vhost.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index b9e853e6094d..59edb5a1ffe2 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -735,10 +735,16 @@ static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
 			 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
 }
 
+/* Make sure 64 bit math will not overflow. */
 static bool vhost_overflow(u64 uaddr, u64 size)
 {
-	/* Make sure 64 bit math will not overflow. */
-	return uaddr > ULONG_MAX || size > ULONG_MAX || uaddr > ULONG_MAX - size;
+	if (uaddr > ULONG_MAX || size > ULONG_MAX)
+		return true;
+
+	if (!size)
+		return false;
+
+	return uaddr > ULONG_MAX - size + 1;
 }
 
 /* Caller should have vq mutex and device mutex. */
-- 
2.11.0


      reply	other threads:[~2021-07-28 13:08 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-28 13:07 [PATCH v2 1/2] vhost-vdpa: Fix integer overflow in vhost_vdpa_process_iotlb_update() Xie Yongji
2021-07-28 13:07 ` Xie Yongji [this message]

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=20210728130756.97-2-xieyongji@bytedance.com \
    --to=xieyongji@bytedance.com \
    --cc=dan.carpenter@oracle.com \
    --cc=jasowang@redhat.com \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mst@redhat.com \
    --cc=virtualization@lists.linux-foundation.org \
    --subject='Re: [PATCH v2 2/2] vhost: Fix the calculation in vhost_overflow()' \
    /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

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).