Fix Just-Works pairing responder role in case where LTK already exists.
Currently when trying to initiate re-pairing from another device
against Linux using Just-Works, pairing fails due to DHKey check failure
on Linux side. This happens because mackey calculation is skipped
totally if LTK already exists due to logic flaw in
smp_cmd_pairing_random() function.
With this fix mackey is calculated right before requesting confirmation
for Just-Works pairing from userspace which in turn fixes the DHKey
calculation.
Fixes: eed467b517e8 ("Bluetooth: fix passkey uninitialized when used")
Signed-off-by: Matias Karhumaa <matias.karhumaa@xxxxxxxxx>
---
net/bluetooth/smp.c | 37 +++++++++----------------------------
1 file changed, 9 insertions(+), 28 deletions(-)
diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index b0c1ee110eff..c3ea50fcac6d 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -2122,7 +2122,7 @@ static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
struct smp_chan *smp = chan->data;
struct hci_conn *hcon = conn->hcon;
u8 *pkax, *pkbx, *na, *nb, confirm_hint;
- u32 passkey;
+ u32 passkey = 0;
int err;
BT_DBG("conn %p", conn);
@@ -2174,24 +2174,6 @@ static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, sizeof(smp->prnd),
smp->prnd);
SMP_ALLOW_CMD(smp, SMP_CMD_DHKEY_CHECK);
-
- /* Only Just-Works pairing requires extra checks */
- if (smp->method != JUST_WORKS)
- goto mackey_and_ltk;
-
- /* If there already exists long term key in local host, leave
- * the decision to user space since the remote device could
- * be legitimate or malicious.
- */
- if (hci_find_ltk(hcon->hdev, &hcon->dst, hcon->dst_type,
- hcon->role)) {
- /* Set passkey to 0. The value can be any number since
- * it'll be ignored anyway.
- */
- passkey = 0;
- confirm_hint = 1;
- goto confirm;
- }
}
mackey_and_ltk:
@@ -2206,17 +2188,16 @@ static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
SMP_ALLOW_CMD(smp, SMP_CMD_DHKEY_CHECK);
}
return 0;
- }
-
- err = smp_g2(smp->tfm_cmac, pkax, pkbx, na, nb, &passkey);
- if (err)
- return SMP_UNSPECIFIED;
-
- confirm_hint = 0;
+ } else if (smp->method != JUST_WORKS) {
+ err = smp_g2(smp->tfm_cmac, pkax, pkbx, na, nb, &passkey);
+ if (err)
+ return SMP_UNSPECIFIED;
-confirm:
- if (smp->method == JUST_WORKS)
+ confirm_hint = 0;
+ } else {
+ /* Just-Works needs hint for userspace */
confirm_hint = 1;
+ }
err = mgmt_user_confirm_request(hcon->hdev, &hcon->dst, hcon->type,
hcon->dst_type, passkey, confirm_hint);
--
2.25.1
