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| author | David S. Miller <davem@davemloft.net> | 2017-02-07 04:41:27 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-02-07 04:41:27 +0100 |
| commit | 432d4f8ab03527958294ad5e539acaebfc4625e3 (patch) | |
| tree | 9acf1060c120551d70a9b31fc8075bf1d834eb98 | |
| parent | tcp: avoid infinite loop in tcp_splice_read() (diff) | |
| parent | macvtap: read vnet_hdr_size once (diff) | |
| download | linux-432d4f8ab03527958294ad5e539acaebfc4625e3.tar.xz linux-432d4f8ab03527958294ad5e539acaebfc4625e3.zip | |
Merge branch 'read-vnet_hdr_sz-once'
Willem de Bruijn says:
====================
read vnet_hdr_sz once
Tuntap devices allow concurrent use and update of field vnet_hdr_sz.
Read the field once to avoid TOCTOU.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/macvtap.c | 4 | ||||
| -rw-r--r-- | drivers/net/tun.c | 10 |
2 files changed, 8 insertions, 6 deletions
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 402618565838..c27011bbe30c 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -681,7 +681,7 @@ 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) @@ -820,7 +820,7 @@ 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 (iov_iter_count(iter) < vnet_hdr_len) return -EINVAL; diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 2cd10b26b650..bfabe180053e 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1170,9 +1170,11 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, } if (tun->flags & IFF_VNET_HDR) { - if (len < tun->vnet_hdr_sz) + int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz); + + if (len < vnet_hdr_sz) return -EINVAL; - len -= tun->vnet_hdr_sz; + len -= vnet_hdr_sz; if (!copy_from_iter_full(&gso, sizeof(gso), from)) return -EFAULT; @@ -1183,7 +1185,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, if (tun16_to_cpu(tun, gso.hdr_len) > len) return -EINVAL; - iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso)); + iov_iter_advance(from, vnet_hdr_sz - sizeof(gso)); } if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) { @@ -1335,7 +1337,7 @@ static ssize_t tun_put_user(struct tun_struct *tun, vlan_hlen = VLAN_HLEN; if (tun->flags & IFF_VNET_HDR) - vnet_hdr_sz = tun->vnet_hdr_sz; + vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz); total = skb->len + vlan_hlen + vnet_hdr_sz; |