Commit 0eca93bc authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller

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

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
Signed-off-by: default avatarHerbert Xu <>
Signed-off-by: default avatarDavid S. Miller <>
parent 86bcebaf
......@@ -518,7 +518,7 @@ static inline struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
int err;
/* Under a page? Don't bother with paged skb. */
if (prepad + len < PAGE_SIZE)
if (prepad + len < PAGE_SIZE || !linear)
linear = len;
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) {
align = NET_IP_ALIGN;
if (unlikely(len < ETH_HLEN))
if (unlikely(len < ETH_HLEN ||
(gso.hdr_len && gso.hdr_len < ETH_HLEN)))
return -EINVAL;
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