From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Date: Wed, 10 Mar 2021 14:13:08 -0800
Subject: [PATCH] Bluetooth: SMP: Fail if remote and local public keys are
 identical
Patch-mainline: v5.13-rc1
Git-commit: 6d19628f539fccf899298ff02ee4c73e4bf6df3f
References: bsc#1186463 CVE-2021-0129 CVE-2020-26558

This fails the pairing procedure when both remote and local non-debug
public keys are identical.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Acked-by: Cho, Yu-Chen <acho@suse.com>
---
 net/bluetooth/smp.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -2693,6 +2693,15 @@ static int smp_cmd_public_key(struct l2c
 	if (skb->len < sizeof(*key))
 		return SMP_INVALID_PARAMS;
 
+	/* Check if remote and local public keys are the same and debug key is
+	 * not in use.
+	 */
+	if (!test_bit(SMP_FLAG_DEBUG_KEY, &smp->flags) &&
+	    !crypto_memneq(key, smp->local_pk, 64)) {
+		bt_dev_err(hdev, "Remote and local public keys are identical");
+		return SMP_UNSPECIFIED;
+	}
+
 	memcpy(smp->remote_pk, key, 64);
 
 	if (test_bit(SMP_FLAG_REMOTE_OOB, &smp->flags)) {