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When skb->len is less than 2, this reads past the valid data in the skb. The ERTM reassembly path correctly calls pskb_may_pull() before reading the SDU length (l2cap_reassemble_sdu, L2CAP_SAR_START case). Apply the same validation to the Enhanced Credit Based Flow Control data path. Fixes: aac23bf63659 ("Bluetooth: Implement LE L2CAP reassembly") Signed-off-by: Hyunwoo Kim --- net/bluetooth/l2cap_core.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index ad98db9632fd..99e9aa104507 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -6682,6 +6682,11 @@ static int l2cap_ecred_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb) if (!chan->sdu) { u16 sdu_len; + if (!pskb_may_pull(skb, L2CAP_SDULEN_SIZE)) { + err = -EINVAL; + goto failed; + } + sdu_len = get_unaligned_le16(skb->data); skb_pull(skb, L2CAP_SDULEN_SIZE); -- 2.43.0