From 880621c2605b82eb5af91a2c94223df6f5a3fb64 Mon Sep 17 00:00:00 2001 From: Martin Blumenstingl Date: Sun, 22 Nov 2015 17:46:09 +0100 Subject: packet: Allow packets with only a header (but no payload) Commit 9c7077622dd91 ("packet: make packet_snd fail on len smaller than l2 header") added validation for the packet size in packet_snd. This change enforces that every packet needs a header (with at least hard_header_len bytes) plus a payload with at least one byte. Before this change the payload was optional. This fixes PPPoE connections which do not have a "Service" or "Host-Uniq" configured (which is violating the spec, but is still widely used in real-world setups). Those are currently failing with the following message: "pppd: packet size is too short (24 <= 24)" Signed-off-by: Martin Blumenstingl Signed-off-by: David S. Miller --- net/packet/af_packet.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/packet') diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 1cf928fb573e..992396aa635c 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2329,8 +2329,8 @@ static void tpacket_destruct_skb(struct sk_buff *skb) static bool ll_header_truncated(const struct net_device *dev, int len) { /* net device doesn't like empty head */ - if (unlikely(len <= dev->hard_header_len)) { - net_warn_ratelimited("%s: packet size is too short (%d <= %d)\n", + if (unlikely(len < dev->hard_header_len)) { + net_warn_ratelimited("%s: packet size is too short (%d < %d)\n", current->comm, len, dev->hard_header_len); return true; } -- cgit