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Commit 0eca93bc authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
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tun: Fix crash with non-GSO users 



When I made the tun driver use non-linear packets as the preferred
option, it broke non-GSO users because they would end up allocating
a completely non-linear packet, which triggers a crash when we call
eth_type_trans.

This patch reverts non-GSO users to using linear packets and adds
a check to ensure that GSO users can't cause crashes in the same
way.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 86bcebaf

drivers/net/tun.c

+3 −2
Original line number Original line Diff line number Diff line
@@ -518,7 +518,7 @@ static inline struct sk_buff *tun_alloc_skb(struct tun_struct *tun, 
	int err;

	int err;





	/* Under a page?  Don't bother with paged skb. */

	/* Under a page?  Don't bother with paged skb. */

	if (prepad + len < PAGE_SIZE)

	if (prepad + len < PAGE_SIZE || !linear)

		linear = len;

		linear = len;





	skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,

	skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
@@ -565,7 +565,8 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, 




	if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {

	if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {

		align = NET_IP_ALIGN;

		align = NET_IP_ALIGN;

		if (unlikely(len < ETH_HLEN))

		if (unlikely(len < ETH_HLEN ||

			     (gso.hdr_len && gso.hdr_len < ETH_HLEN)))

			return -EINVAL;

			return -EINVAL;

	}

	}