linux-kernel - Re: [PATCH] vhost: Fix warnings and bad type handling

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20091122102801.GA13644@redhat.com>
Date:	Sun, 22 Nov 2009 12:28:01 +0200
From:	"Michael S. Tsirkin" <mst@...hat.com>
To:	Alan Cox <alan@...ux.intel.com>,
	Rusty Russell <rusty@...tcorp.com.au>,
	virtualization@...ts.linux-foundation.org, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] vhost: Fix warnings and bad type handling


From: Alan Cox <alan@...ux.intel.com>
Subject: [PATCH] vhost: fix warnings on 32 bit systems

Fix compiler warning about discarding top 32 bit
of data on 32 bit systems, and document that
dicarded bits must be 0.

Signed-off-by: Alan Cox <alan@...ux.intel.com>
Signed-off-by: Michael S. Tsirkin <mst@...hat.com>
---

So I think the below slightly tweaked version of
Alan's patch is a bit better. OK?

 drivers/vhost/vhost.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 97233d5..e7b4dea 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -322,6 +322,8 @@ static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp)
 			r = -EOPNOTSUPP;
 			break;
 		}
+		/* For 32bit, verify that the top 32bits of the user
+		   data are set to zero. */
 		if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
 		    (u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
 		    (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) {
@@ -334,7 +336,8 @@ static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp)
 			r = -EINVAL;
 			break;
 		}
-		r = init_used(vq, (struct vring_used __user *)a.used_user_addr);
+		r = init_used(vq, (struct vring_used __user *)(unsigned long)
+			      a.used_user_addr);
 		if (r)
 			break;
 		vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
-- 
1.6.5.2.143.g8cc62

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/