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authorSven Eckelmann <sven@narfation.org>2018-12-31 22:31:01 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-02-15 08:07:39 +0100
commit1474d65b85cfdb60aed3fdf095887f9d8232f121 (patch)
parenta5a1ce4c3f088d13178a029327a1eb3452298957 (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 05bc176decf0..835af771a9fd 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -211,6 +211,8 @@ static int batadv_interface_tx(struct sk_buff *skb,
vid = batadv_get_vid(skb, 0);
+ skb_reset_mac_header(skb);
ethhdr = eth_hdr(skb);
switch (ntohs(ethhdr->h_proto)) {