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authorSven Eckelmann <sven@narfation.org>2018-12-31 22:31:01 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-02-20 10:13:20 +0100
commitb2942d59a3cd66a5202eedcd41e751c0d0bd6e5e (patch)
parent8fe161469f1847d14068aec829d77e428cb653d1 (diff)
batman-adv: Force mac header to start of data on xmit
commit 9114daa825fc3f335f9bea3313ce667090187280 upstream. The caller of ndo_start_xmit may not already have called skb_reset_mac_header. The returned value of skb_mac_header/eth_hdr therefore can be in the wrong position and even outside the current skbuff. This for example happens when the user binds to the device using a PF_PACKET-SOCK_RAW with enabled qdisc-bypass: int opt = 4; setsockopt(sock, SOL_PACKET, PACKET_QDISC_BYPASS, &opt, sizeof(opt)); Since eth_hdr is used all over the codebase, the batadv_interface_tx function must always take care of resetting it. Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol") Reported-by: syzbot+9d7405c7faa390e60b4e@syzkaller.appspotmail.com Reported-by: syzbot+7d20bc3f1ddddc0f9079@syzkaller.appspotmail.com Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 2 insertions, 0 deletions
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 9f1fe6169bef..5aeb585571ed 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -209,6 +209,8 @@ static int batadv_interface_tx(struct sk_buff *skb,
soft_iface->trans_start = jiffies;
vid = batadv_get_vid(skb, 0);
+ skb_reset_mac_header(skb);
ethhdr = eth_hdr(skb);
switch (ntohs(ethhdr->h_proto)) {