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tun: fix tun_chr_aio_write so that aio works

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aio_write gets const struct iovec * but tun_chr_aio_write casts this to struct
iovec * and modifies the iovec. As a result, attempts to use io_submit
to send packets to a tun device fail with weird errors such as EINVAL.

Since tun is the only user of skb_copy_datagram_from_iovec, we can
fix this simply by changing the later so that it does not
touch the iovec passed to it.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Michael S. Tsirkin
2009-04-20 01:26:11 +00:00
committed by David S. Miller
parent 43b39dcdbd
commit 6f26c9a755
5 changed files with 30 additions and 17 deletions
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13
drivers/net/tun.c
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@@ -540,31 +540,34 @@ static inline struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
/* Get packet from user space buffer */
static __inline__ ssize_t tun_get_user(struct tun_struct *tun,
struct iovec *iv, size_t count,
const struct iovec *iv, size_t count,
int noblock)
{
struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
struct sk_buff *skb;
size_t len = count, align = 0;
struct virtio_net_hdr gso = { 0 };
int offset = 0;
if (!(tun->flags & TUN_NO_PI)) {
if ((len -= sizeof(pi)) > count)
return -EINVAL;
if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
return -EFAULT;
offset += sizeof(pi);
}
if (tun->flags & TUN_VNET_HDR) {
if ((len -= sizeof(gso)) > count)
return -EINVAL;
if (memcpy_fromiovec((void *)&gso, iv, sizeof(gso)))
if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
return -EFAULT;
if (gso.hdr_len > len)
return -EINVAL;
offset += sizeof(pi);
}
if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
@@ -581,7 +584,7 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun,
return PTR_ERR(skb);
}
if (skb_copy_datagram_from_iovec(skb, 0, iv, len)) {
if (skb_copy_datagram_from_iovec(skb, 0, iv, offset, len)) {
tun->dev->stats.rx_dropped++;
kfree_skb(skb);
return -EFAULT;
@@ -673,7 +676,7 @@ static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
result = tun_get_user(tun, (struct iovec *)iv, iov_length(iv, count),
result = tun_get_user(tun, iv, iov_length(iv, count),
file->f_flags & O_NONBLOCK);
tun_put(tun);