5.4-stable review patch. If anyone has any objections, please let me know.
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From: Stanislav Fort stanislav.fort@aisle.com
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: 2df5278b0267 ("batman-adv: network coding - receive coded packets and decode them") Cc: stable@vger.kernel.org Reported-by: Stanislav Fort disclosure@aisle.com Signed-off-by: Stanislav Fort stanislav.fort@aisle.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 --- net/batman-adv/network-coding.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
--- a/net/batman-adv/network-coding.c +++ b/net/batman-adv/network-coding.c @@ -1694,7 +1694,12 @@ batadv_nc_skb_decode_packet(struct batad
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: