diff options
| author | Willem de Bruijn <willemb@google.com> | 2017-02-03 18:20:49 -0500 |
|---|---|---|
| committer | Mister Oyster <oysterized@gmail.com> | 2017-07-04 11:51:33 +0200 |
| commit | 81bdc97a16cb396cc748108a5042709b00713e75 (patch) | |
| tree | 2148c21c13e8a8c6e26e762ee478b8043bf6742d /drivers/net | |
| parent | 5e74ded03d8321b49dfadfdcabd3c6c39d8ab649 (diff) | |
macvtap: read vnet_hdr_size once
commit 837585a5375c38d40361cfe64e6fd11e1addb936 upstream.
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>
[wt: s/READ_ONCE/ACCESS_ONCE]
Signed-off-by: Willy Tarreau <w@1wt.eu>
Diffstat (limited to 'drivers/net')
| -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 8fc46fcae..1c51abbec 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -678,7 +678,7 @@ 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 = ACCESS_ONCE(q->vnet_hdr_sz); err = -EINVAL; if (len < vnet_hdr_len) @@ -809,7 +809,7 @@ 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 = ACCESS_ONCE(q->vnet_hdr_sz); if ((len -= vnet_hdr_len) < 0) return -EINVAL; |