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Commit 30fc4724 authored by Stanislav Fort's avatar Stanislav Fort Committed by Greg Kroah-Hartman
Browse files

batman-adv: fix OOB read/write in network-coding decode 



commit d77b6ff0ce35a6d0b0b7b9581bc3f76d041d4087 upstream.

batadv_nc_skb_decode_packet() trusts coded_len and checks only against
skb->len. XOR starts at sizeof(struct batadv_unicast_packet), reducing
payload headroom, and the source skb length is not verified, allowing an
out-of-bounds read and a small out-of-bounds write.

Validate that coded_len fits within the payload area of both destination
and source sk_buffs before XORing.

Fixes: 2df5278b ("batman-adv: network coding - receive coded packets and decode them")
Cc: stable@vger.kernel.org
Reported-by: default avatarStanislav Fort <disclosure@aisle.com>
Signed-off-by: default avatarStanislav Fort <stanislav.fort@aisle.com>
Signed-off-by: default avatarSven Eckelmann <sven@narfation.org>
Signed-off-by: default avatarSimon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6c9b0357

net/batman-adv/network-coding.c

+6 −1
Original line number Diff line number Diff line
@@ -1694,7 +1694,12 @@ batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb, 


	coding_len = ntohs(coded_packet_tmp.coded_len);



	if (coding_len > skb->len)

	/* ensure dst buffer is large enough (payload only) */

	if (coding_len + h_size > skb->len)

		return NULL;



	/* ensure src buffer is large enough (payload only) */

	if (coding_len + h_size > nc_packet->skb->len)

		return NULL;



	/* Here the magic is reversed: