diff options
| author | Willem de Bruijn <willemb@google.com> | 2017-02-04 02:20:49 +0300 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2017-03-01 11:59:48 +0300 |
| commit | e1413a0ea8c90c4e5c63ebdcbbff620658b91182 (patch) | |
| tree | f5b3e26b45882d37a3ba1d980f1f0385d908e910 /drivers | |
| parent | 5cc7e0016eba9630b22ba7dd6e3d45940790d787 (diff) | |
| download | linux-e1413a0ea8c90c4e5c63ebdcbbff620658b91182.tar.xz | |
macvtap: read vnet_hdr_size once
[ Upstream commit 837585a5375c38d40361cfe64e6fd11e1addb936 ]
When IFF_VNET_HDR is enabled, a virtio_net header must precede data.
Data length is verified to be greater than or equal to expected header
length tun->vnet_hdr_sz before copying.
Macvtap functions read the value once, but unless READ_ONCE is used,
the compiler may ignore this and read multiple times. Enforce a single
read and locally cached value to avoid updates between test and use.
Signed-off-by: Willem de Bruijn <willemb@google.com>
Suggested-by: Eric Dumazet <edumazet@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/macvtap.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 98ce4feb9a79..2f6da225fab4 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -655,7 +655,7 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, size_t linear; if (q->flags & IFF_VNET_HDR) { - vnet_hdr_len = q->vnet_hdr_sz; + vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz); err = -EINVAL; if (len < vnet_hdr_len) @@ -792,7 +792,7 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q, if (q->flags & IFF_VNET_HDR) { struct virtio_net_hdr vnet_hdr; - vnet_hdr_len = q->vnet_hdr_sz; + vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz); if ((len -= vnet_hdr_len) < 0) return -EINVAL; |