From: Willem de Bruijn <willemb@google.com>
Subject: packet: reset network header if packet shorter than ll
reserved space
Patch-mainline: v4.18-rc6
Git-commit: 993675a3100b16a4c80dfd70cbcde8ea7127b31d
References: git-fixes
If variable length link layer headers result in a packet shorter
than dev->hard_header_len, reset the network header offset. Else
skb->mac_len may exceed skb->len after skb_mac_reset_len.
packet_sendmsg_spkt already has similar logic.
Fixes: b84bbaf7a6c8 ("packet: in packet_snd start writing at link layer allocation")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Denis Kirjanov <dkirjanov@suse.com>
---
net/packet/af_packet.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 9689622eaef7..cf7652bb2218 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2934,6 +2934,8 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
goto out_free;
} else if (reserve) {
skb_reserve(skb, -reserve);
+ if (len < reserve)
+ skb_reset_network_header(skb);
}
/* Returns -EFAULT on error */
--
2.12.3