Hi Frédéric,
On Tue, Apr 8, 2025 at 1:09 PM Frédéric Danis
<frederic.danis@xxxxxxxxxxxxx> wrote:
>
> This is required for passing GAP/SEC/SEM/BI-04-C PTS test case:
> Security Mode 4 Level 4, Responder - Invalid Encryption Key Size
> - 128 bit
>
> This tests the security key with size from 1 to 15 bytes while the
> Security Mode 4 Level 4 requests 16 bytes key size.
>
> Currently PTS fails with the following logs:
> - expected:Connection Response:
> Code: [3 (0x03)] Code
> Identifier: (lt)WildCard: Exists(gt)
> Length: [8 (0x0008)]
> Destination CID: (lt)WildCard: Exists(gt)
> Source CID: [64 (0x0040)]
> Result: [3 (0x0003)] Connection refused - Security block
> Status: (lt)WildCard: Exists(gt),
> but received:Connection Response:
> Code: [3 (0x03)] Code
> Identifier: [1 (0x01)]
> Length: [8 (0x0008)]
> Destination CID: [64 (0x0040)]
> Source CID: [64 (0x0040)]
> Result: [0 (0x0000)] Connection Successful
> Status: [0 (0x0000)] No further information available
>
> And HCI logs:
> < HCI Command: Read Encrypti.. (0x05|0x0008) plen 2
> Handle: 14 Address: 00:1B:DC:F2:24:10 (Vencer Co., Ltd.)
> > HCI Event: Command Complete (0x0e) plen 7
> Read Encryption Key Size (0x05|0x0008) ncmd 1
> Status: Success (0x00)
> Handle: 14 Address: 00:1B:DC:F2:24:10 (Vencer Co., Ltd.)
> Key size: 7
> > ACL Data RX: Handle 14 flags 0x02 dlen 12
> L2CAP: Connection Request (0x02) ident 1 len 4
> PSM: 4097 (0x1001)
> Source CID: 64
> < ACL Data TX: Handle 14 flags 0x00 dlen 16
> L2CAP: Connection Response (0x03) ident 1 len 8
> Destination CID: 64
> Source CID: 64
> Result: Connection successful (0x0000)
> Status: No further information available (0x0000)
>
> Signed-off-by: Frédéric Danis <frederic.danis@xxxxxxxxxxxxx>
> ---
> net/bluetooth/l2cap_core.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index c7b66b2ea9f2..f2ab09582146 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -3997,6 +3997,13 @@ static void l2cap_connect(struct l2cap_conn *conn, struct l2cap_cmd_hdr *cmd,
> goto response;
> }
>
> + /* Check the encryption key size */
> + if (!l2cap_check_enc_key_size(conn->hcon)) {
> + conn->disc_reason = HCI_ERROR_AUTH_FAILURE;
> + result = L2CAP_CR_SEC_BLOCK;
> + goto response;
> + }
> +
Hmm maybe we should incorporate this is the statement before:
/* Check if the ACL is secure enough (if not SDP) */
if (psm != cpu_to_le16(L2CAP_PSM_SDP) &&
!hci_conn_check_link_mode(conn->hcon)) {
conn->disc_reason = HCI_ERROR_AUTH_FAILURE;
result = L2CAP_CR_SEC_BLOCK;
goto response;
}
That said I don't quite understand why the likes of
hci_conn_check_link_mode is not checking the key size since it is
already doing security level checks, either way that indeed seem to be
missing for incoming connection requests.
> result = L2CAP_CR_NO_MEM;
>
> /* Check for valid dynamic CID range (as per Erratum 3253) */
> --
> 2.43.0
>
>
--
Luiz Augusto von Dentz
