Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux

Bluetooth: SMP: If an unallowed command is received consider it a failure

If a command is received while a bonding is ongoing consider it a
pairing failure so the session is cleanup properly and the device is
disconnected immediately instead of continuing with other commands that
may result in the session to get stuck without ever completing such as
the case bellow:

> ACL Data RX: Handle 2048 flags 0x02 dlen 21
SMP: Identity Information (0x08) len 16
Identity resolving key[16]: d7e08edef97d3e62cd2331f82d8073b0
> ACL Data RX: Handle 2048 flags 0x02 dlen 21
SMP: Signing Information (0x0a) len 16
Signature key[16]: 1716c536f94e843a9aea8b13ffde477d
Bluetooth: hci0: unexpected SMP command 0x0a from XX:XX:XX:XX:XX:XX
> ACL Data RX: Handle 2048 flags 0x02 dlen 12
SMP: Identity Address Information (0x09) len 7
Address: XX:XX:XX:XX:XX:XX (Intel Corporate)

While accourding to core spec 6.1 the expected order is always BD_ADDR
first first then CSRK:

When using LE legacy pairing, the keys shall be distributed in the
following order:

LTK by the Peripheral

EDIV and Rand by the Peripheral

IRK by the Peripheral

BD_ADDR by the Peripheral

CSRK by the Peripheral

LTK by the Central

EDIV and Rand by the Central

IRK by the Central

BD_ADDR by the Central

CSRK by the Central

When using LE Secure Connections, the keys shall be distributed in the
following order:

IRK by the Peripheral

BD_ADDR by the Peripheral

CSRK by the Peripheral

IRK by the Central

BD_ADDR by the Central

CSRK by the Central

According to the Core 6.1 for commands used for key distribution "Key
Rejected" can be used:

'3.6.1. Key distribution and generation

A device may reject a distributed key by sending the Pairing Failed command
with the reason set to "Key Rejected".

Fixes: b28b4943660f ("Bluetooth: Add strict checks for allowed SMP PDUs")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

+19 -1
+18 -1
net/bluetooth/smp.c
··· 2977 2977 if (code > SMP_CMD_MAX) 2978 2978 goto drop; 2979 2979 2980 - if (smp && !test_and_clear_bit(code, &smp->allow_cmd)) 2980 + if (smp && !test_and_clear_bit(code, &smp->allow_cmd)) { 2981 + /* If there is a context and the command is not allowed consider 2982 + * it a failure so the session is cleanup properly. 2983 + */ 2984 + switch (code) { 2985 + case SMP_CMD_IDENT_INFO: 2986 + case SMP_CMD_IDENT_ADDR_INFO: 2987 + case SMP_CMD_SIGN_INFO: 2988 + /* 3.6.1. Key distribution and generation 2989 + * 2990 + * A device may reject a distributed key by sending the 2991 + * Pairing Failed command with the reason set to 2992 + * "Key Rejected". 2993 + */ 2994 + smp_failure(conn, SMP_KEY_REJECTED); 2995 + break; 2996 + } 2981 2997 goto drop; 2998 + } 2982 2999 2983 3000 /* If we don't have a context the only allowed commands are 2984 3001 * pairing request and security request.
+1
net/bluetooth/smp.h
··· 138 138 #define SMP_NUMERIC_COMP_FAILED 0x0c 139 139 #define SMP_BREDR_PAIRING_IN_PROGRESS 0x0d 140 140 #define SMP_CROSS_TRANSP_NOT_ALLOWED 0x0e 141 + #define SMP_KEY_REJECTED 0x0f 141 142 142 143 #define SMP_MIN_ENC_KEY_SIZE 7 143 144 #define SMP_MAX_ENC_KEY_SIZE 16