From: Jason Wang <jasowang@redhat.com>
Date: Tue, 9 Apr 2019 04:10:25 +0000 (+0800)
Subject: vhost: reject zero size iova range
X-Git-Tag: Ubuntu-4.15.0-61.68~2184
X-Git-Url: https://git.proxmox.com/?p=mirror_ubuntu-bionic-kernel.git;a=commitdiff_plain;h=0b950ef9b91e6ab9f4dc0e07bdf24b7dd6d75388

vhost: reject zero size iova range

BugLink: https://bugs.launchpad.net/bugs/1838349

[ Upstream commit 813dbeb656d6c90266f251d8bd2b02d445afa63f ]

We used to accept zero size iova range which will lead a infinite loop
in translate_desc(). Fixing this by failing the request in this case.

Reported-by: syzbot+d21e6e297322a900c128@syzkaller.appspotmail.com
Fixes: 6b1e6cc7 ("vhost: new device IOTLB API")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
---

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 7cbc18bdaf67..6f86dd6cc4b3 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -918,8 +918,12 @@ static int vhost_new_umem_range(struct vhost_umem *umem,
 				u64 start, u64 size, u64 end,
 				u64 userspace_addr, int perm)
 {
-	struct vhost_umem_node *tmp, *node = kmalloc(sizeof(*node), GFP_ATOMIC);
+	struct vhost_umem_node *tmp, *node;
 
+	if (!size)
+		return -EFAULT;
+
+	node = kmalloc(sizeof(*node), GFP_ATOMIC);
 	if (!node)
 		return -ENOMEM;