linux-kernel - [PATCH 2/3] virtio_balloon: Fix endian bug

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: <1334208995-29985-3-git-send-email-david@gibson.dropbear.id.au>
Date:	Thu, 12 Apr 2012 15:36:34 +1000
From:	David Gibson <david@...son.dropbear.id.au>
To:	rusty@...tcorp.com.au, mst@...hat.com
Cc:	virtualization@...ts.linux-foundation.org,
	linux-kernel@...r.kernel.org, paulus@...ba.org,
	qemu-devel@...gnu.org, David Gibson <david@...son.dropbear.id.au>
Subject: [PATCH 2/3] virtio_balloon: Fix endian bug

Although virtio config space fields are usually in guest-native endian,
the spec for the virtio balloon device explicitly states that both fields
in its config space are little-endian.

However, the current virtio_balloon driver does not have a suitable endian
swap for the 'num_pages' field, although it does have one for the 'actual'
field.  This patch corrects the bug, adding sparse annotation while we're
at it.

Signed-off-by: David Gibson <david@...son.dropbear.id.au>
---
 drivers/virtio/virtio_balloon.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 6c07793..553cc1f 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -238,11 +238,14 @@ static void virtballoon_changed(struct virtio_device *vdev)
 
 static inline s64 towards_target(struct virtio_balloon *vb)
 {
-	u32 v;
+	__le32 v;
+	s64 target;
+
 	vb->vdev->config->get(vb->vdev,
 			      offsetof(struct virtio_balloon_config, num_pages),
 			      &v, sizeof(v));
-	return (s64)v - vb->num_pages;
+	target = le32_to_cpu(v);
+	return target - vb->num_pages;
 }
 
 static void update_balloon_size(struct virtio_balloon *vb)
-- 
1.7.9.5

--
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/