From b541260615f601ae1b5d6d0cc54e790de706303b Mon Sep 17 00:00:00 2001 From: Luiz Augusto von Dentz Date: Thu, 5 Oct 2023 13:59:59 -0700 Subject: [PATCH] Bluetooth: hci_event: Fix using memcmp when comparing keys memcmp is not consider safe to use with cryptographic secrets: 'Do not use memcmp() to compare security critical data, such as cryptographic secrets, because the required CPU time depends on the number of equal bytes.' While usage of memcmp for ZERO_KEY may not be considered a security critical data, it can lead to more usage of memcmp with pairing keys which could introduce more security problems. Fixes: 455c2ff0a558 ("Bluetooth: Fix BR/EDR out-of-band pairing with only initiator data") Fixes: 33155c4aae52 ("Bluetooth: hci_event: Ignore NULL link key") Signed-off-by: Luiz Augusto von Dentz --- net/bluetooth/hci_event.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 7e1c875..9b252a6 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -26,6 +26,8 @@ /* Bluetooth HCI event handling. */ #include +#include +#include #include #include @@ -4754,7 +4756,7 @@ static void hci_link_key_notify_evt(struct hci_dev *hdev, void *data, goto unlock; /* Ignore NULL link key against CVE-2020-26555 */ - if (!memcmp(ev->link_key, ZERO_KEY, HCI_LINK_KEY_SIZE)) { + if (!crypto_memneq(ev->link_key, ZERO_KEY, HCI_LINK_KEY_SIZE)) { bt_dev_dbg(hdev, "Ignore NULL link key (ZERO KEY) for %pMR", &ev->bdaddr); hci_disconnect(conn, HCI_ERROR_AUTH_FAILURE); @@ -5294,8 +5296,8 @@ static u8 bredr_oob_data_present(struct hci_conn *conn) * available, then do not declare that OOB data is * present. */ - if (!memcmp(data->rand256, ZERO_KEY, 16) || - !memcmp(data->hash256, ZERO_KEY, 16)) + if (!crypto_memneq(data->rand256, ZERO_KEY, 16) || + !crypto_memneq(data->hash256, ZERO_KEY, 16)) return 0x00; return 0x02; @@ -5305,8 +5307,8 @@ static u8 bredr_oob_data_present(struct hci_conn *conn) * not supported by the hardware, then check that if * P-192 data values are present. */ - if (!memcmp(data->rand192, ZERO_KEY, 16) || - !memcmp(data->hash192, ZERO_KEY, 16)) + if (!crypto_memneq(data->rand192, ZERO_KEY, 16) || + !crypto_memneq(data->hash192, ZERO_KEY, 16)) return 0x00; return 0x01; -- 2.7.4