[PATCH AUTOSEL 4.18 20/48] Bluetooth: SMP: Fix trying to use non-existent local OOB data

[Sasha Levin]

From: Johan Hedberg <johan.hedberg@xxxxxxxxx>

[ Upstream commit 94f14e4728125f979629b2b020d31cd718191626 ]

A remote device may claim that it has received our OOB data, even
though we never geneated it. Add a new flag to track whether we
actually have OOB data, and ignore the remote peer's flag if haven't
generated OOB data.

Signed-off-by: Johan Hedberg <johan.hedberg@xxxxxxxxx>
Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 net/bluetooth/smp.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index ae91e2d40056..9752879fdd3a 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -83,6 +83,7 @@ enum {
 
 struct smp_dev {
 	/* Secure Connections OOB data */
+	bool			local_oob;
 	u8			local_pk[64];
 	u8			local_rand[16];
 	bool			debug_key;
@@ -599,6 +600,8 @@ int smp_generate_oob(struct hci_dev *hdev, u8 hash[16], u8 rand[16])
 
 	memcpy(rand, smp->local_rand, 16);
 
+	smp->local_oob = true;
+
 	return 0;
 }
 
@@ -1785,7 +1788,7 @@ static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
 	 * successfully received our local OOB data - therefore set the
 	 * flag to indicate that local OOB is in use.
 	 */
-	if (req->oob_flag == SMP_OOB_PRESENT)
+	if (req->oob_flag == SMP_OOB_PRESENT && SMP_DEV(hdev)->local_oob)
 		set_bit(SMP_FLAG_LOCAL_OOB, &smp->flags);
 
 	/* SMP over BR/EDR requires special treatment */
@@ -1967,7 +1970,7 @@ static u8 smp_cmd_pairing_rsp(struct l2cap_conn *conn, struct sk_buff *skb)
 	 * successfully received our local OOB data - therefore set the
 	 * flag to indicate that local OOB is in use.
 	 */
-	if (rsp->oob_flag == SMP_OOB_PRESENT)
+	if (rsp->oob_flag == SMP_OOB_PRESENT && SMP_DEV(hdev)->local_oob)
 		set_bit(SMP_FLAG_LOCAL_OOB, &smp->flags);
 
 	smp->prsp[0] = SMP_CMD_PAIRING_RSP;
@@ -3230,6 +3233,7 @@ static struct l2cap_chan *smp_add_cid(struct hci_dev *hdev, u16 cid)
 		return ERR_CAST(tfm_ecdh);
 	}
 
+	smp->local_oob = false;
 	smp->tfm_aes = tfm_aes;
 	smp->tfm_cmac = tfm_cmac;
 	smp->tfm_ecdh = tfm_ecdh;
-- 
2.17.1