Once skb_realloc_headroom() is called, tiph might point to freed memory.
Cache tiph->ttl value before the reallocation, to avoid unexpected
behavior.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
int gre_hlen;
__be32 dst;
int mtu;
+ u8 ttl;
if (skb->ip_summed == CHECKSUM_PARTIAL &&
skb_checksum_help(skb))
goto tx_error;
}
+ ttl = tiph->ttl;
tos = tiph->tos;
if (tos == 1) {
tos = 0;
dev_kfree_skb(skb);
skb = new_skb;
old_iph = ip_hdr(skb);
+ /* Warning : tiph value might point to freed memory */
}
skb_reset_transport_header(skb);
iph->tos = ipgre_ecn_encapsulate(tos, old_iph, skb);
iph->daddr = fl4.daddr;
iph->saddr = fl4.saddr;
+ iph->ttl = ttl;
- if ((iph->ttl = tiph->ttl) == 0) {
+ if (ttl == 0) {
if (skb->protocol == htons(ETH_P_IP))
iph->ttl = old_iph->ttl;
#if IS_ENABLED(CONFIG_IPV6)