diff options
| author | Sven Eckelmann | 2019-08-22 08:55:36 +0200 |
|---|---|---|
| committer | Simon Wunderlich | 2019-08-23 18:20:31 +0200 |
| commit | 0ff0f15a32c093381ad1abc06abe85afb561ab28 (patch) | |
| tree | 922d1d158866b0c7ab695628ad8a64a8e59be3c3 /net/batman-adv | |
| parent | a15d56a60760aa9dbe26343b9a0ac5228f35d445 (diff) | |
batman-adv: Only read OGM2 tvlv_len after buffer len check
Multiple batadv_ogm2_packet can be stored in an skbuff. The functions
batadv_v_ogm_send_to_if() uses batadv_v_ogm_aggr_packet() to check if there
is another additional batadv_ogm2_packet in the skb or not before they
continue processing the packet.
The length for such an OGM2 is BATADV_OGM2_HLEN +
batadv_ogm2_packet->tvlv_len. The check must first check that at least
BATADV_OGM2_HLEN bytes are available before it accesses tvlv_len (which is
part of the header. Otherwise it might try read outside of the currently
available skbuff to get the content of tvlv_len.
Fixes: 9323158ef9f4 ("batman-adv: OGMv2 - implement originators logic")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Diffstat (limited to 'net/batman-adv')
| -rw-r--r-- | net/batman-adv/bat_v_ogm.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c index fad95ef64e01..bc06e3cdfa84 100644 --- a/net/batman-adv/bat_v_ogm.c +++ b/net/batman-adv/bat_v_ogm.c @@ -631,17 +631,23 @@ batadv_v_ogm_process_per_outif(struct batadv_priv *bat_priv, * batadv_v_ogm_aggr_packet() - checks if there is another OGM aggregated * @buff_pos: current position in the skb * @packet_len: total length of the skb - * @tvlv_len: tvlv length of the previously considered OGM + * @ogm2_packet: potential OGM2 in buffer * * Return: true if there is enough space for another OGM, false otherwise. */ -static bool batadv_v_ogm_aggr_packet(int buff_pos, int packet_len, - __be16 tvlv_len) +static bool +batadv_v_ogm_aggr_packet(int buff_pos, int packet_len, + const struct batadv_ogm2_packet *ogm2_packet) { int next_buff_pos = 0; - next_buff_pos += buff_pos + BATADV_OGM2_HLEN; - next_buff_pos += ntohs(tvlv_len); + /* check if there is enough space for the header */ + next_buff_pos += buff_pos + sizeof(*ogm2_packet); + if (next_buff_pos > packet_len) + return false; + + /* check if there is enough space for the optional TVLV */ + next_buff_pos += ntohs(ogm2_packet->tvlv_len); return (next_buff_pos <= packet_len) && (next_buff_pos <= BATADV_MAX_AGGREGATION_BYTES); @@ -818,7 +824,7 @@ int batadv_v_ogm_packet_recv(struct sk_buff *skb, ogm_packet = (struct batadv_ogm2_packet *)skb->data; while (batadv_v_ogm_aggr_packet(ogm_offset, skb_headlen(skb), - ogm_packet->tvlv_len)) { + ogm_packet)) { batadv_v_ogm_process(skb, ogm_offset, if_incoming); ogm_offset += BATADV_OGM2_HLEN; |