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>
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commit
432d4f8ab0
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@ -681,7 +681,7 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
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size_t linear;
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if (q->flags & IFF_VNET_HDR) {
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vnet_hdr_len = q->vnet_hdr_sz;
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vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);
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err = -EINVAL;
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if (len < vnet_hdr_len)
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@ -820,7 +820,7 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q,
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if (q->flags & IFF_VNET_HDR) {
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struct virtio_net_hdr vnet_hdr;
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vnet_hdr_len = q->vnet_hdr_sz;
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vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);
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if (iov_iter_count(iter) < vnet_hdr_len)
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return -EINVAL;
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@ -1170,9 +1170,11 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
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}
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if (tun->flags & IFF_VNET_HDR) {
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if (len < tun->vnet_hdr_sz)
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int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
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if (len < vnet_hdr_sz)
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return -EINVAL;
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len -= tun->vnet_hdr_sz;
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len -= vnet_hdr_sz;
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if (!copy_from_iter_full(&gso, sizeof(gso), from))
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return -EFAULT;
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@ -1183,7 +1185,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
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if (tun16_to_cpu(tun, gso.hdr_len) > len)
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return -EINVAL;
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iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso));
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iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
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}
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if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) {
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@ -1335,7 +1337,7 @@ static ssize_t tun_put_user(struct tun_struct *tun,
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vlan_hlen = VLAN_HLEN;
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if (tun->flags & IFF_VNET_HDR)
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vnet_hdr_sz = tun->vnet_hdr_sz;
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vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
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total = skb->len + vlan_hlen + vnet_hdr_sz;
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