diff mbox series

Bluetooth: Add more enc key size check

Message ID ZXbIWMZyZIYyetff@alexlu (mailing list archive)
State Superseded
Headers show
Series Bluetooth: Add more enc key size check | expand

Checks

Context Check Description
tedd_an/pre-ci_am success Success
tedd_an/CheckPatch success CheckPatch PASS
tedd_an/GitLint success Gitlint PASS
tedd_an/SubjectPrefix success Gitlint PASS
tedd_an/BuildKernel success BuildKernel PASS
tedd_an/CheckAllWarning success CheckAllWarning PASS
tedd_an/CheckSparse warning CheckSparse WARNING net/bluetooth/l2cap_core.c:1676:52: warning: incorrect type in assignment (different base types)net/bluetooth/l2cap_core.c:1676:52: expected restricted __le16 [assigned] [usertype] resultnet/bluetooth/l2cap_core.c:1676:52: got int
tedd_an/CheckSmatch success CheckSparse PASS
tedd_an/BuildKernel32 success BuildKernel32 PASS
tedd_an/TestRunnerSetup success TestRunnerSetup PASS
tedd_an/TestRunner_l2cap-tester success TestRunner PASS
tedd_an/TestRunner_iso-tester success TestRunner PASS
tedd_an/TestRunner_bnep-tester success TestRunner PASS
tedd_an/TestRunner_mgmt-tester fail TestRunner_mgmt-tester: Total: 497, Passed: 496 (99.8%), Failed: 1, Not Run: 0
tedd_an/TestRunner_rfcomm-tester success TestRunner PASS
tedd_an/TestRunner_sco-tester success TestRunner PASS
tedd_an/TestRunner_ioctl-tester success TestRunner PASS
tedd_an/TestRunner_mesh-tester success TestRunner PASS
tedd_an/TestRunner_smp-tester success TestRunner PASS
tedd_an/TestRunner_userchan-tester success TestRunner PASS
tedd_an/IncrementalBuild success Incremental Build PASS

Commit Message

Alex Lu Dec. 11, 2023, 8:29 a.m. UTC 
From: Alex Lu <alex_lu@realsil.com.cn>

When we are slave role and receives l2cap conn req when encryption has
started, we should check the enc key size to avoid KNOB attack or BLUFFS
attack.
From SIG recommendation, implementations are advised to reject
service-level connections on an encrypted baseband link with key
strengths below 7 octets.

The btmon log below shows the case that lacks enc key size check.

> HCI Event: Connect Request (0x04) plen 10
        Address: BB:22:33:44:55:99 (OUI BB-22-33)
        Class: 0x480104
          Major class: Computer (desktop, notebook, PDA, organizers)
          Minor class: Desktop workstation
          Capturing (Scanner, Microphone)
          Telephony (Cordless telephony, Modem, Headset)
        Link type: ACL (0x01)
< HCI Command: Accept Connection Request (0x01|0x0009) plen 7
        Address: BB:22:33:44:55:99 (OUI BB-22-33)
        Role: Peripheral (0x01)
> HCI Event: Command Status (0x0f) plen 4
      Accept Connection Request (0x01|0x0009) ncmd 2
        Status: Success (0x00)
> HCI Event: Connect Complete (0x03) plen 11
        Status: Success (0x00)
        Handle: 1
        Address: BB:22:33:44:55:99 (OUI BB-22-33)
        Link type: ACL (0x01)
        Encryption: Disabled (0x00)
...

> HCI Event: Encryption Change (0x08) plen 4
        Status: Success (0x00)
        Handle: 1 Address: BB:22:33:44:55:99 (OUI BB-22-33)
        Encryption: Enabled with E0 (0x01)
< HCI Command: Read Encryption Key Size (0x05|0x0008) plen 2
        Handle: 1 Address: BB:22:33:44:55:99 (OUI BB-22-33)
> HCI Event: Command Complete (0x0e) plen 7
      Read Encryption Key Size (0x05|0x0008) ncmd 2
        Status: Success (0x00)
        Handle: 1 Address: BB:22:33:44:55:99 (OUI BB-22-33)
        Key size: 6
...

// We should check the enc key size
> ACL Data RX: Handle 1 flags 0x02 dlen 12
      L2CAP: Connection Request (0x02) ident 3 len 4
        PSM: 25 (0x0019)
        Source CID: 64
< ACL Data TX: Handle 1 flags 0x00 dlen 16
      L2CAP: Connection Response (0x03) ident 3 len 8
        Destination CID: 64
        Source CID: 64
        Result: Connection pending (0x0001)
        Status: Authorization pending (0x0002)
> HCI Event: Number of Completed Packets (0x13) plen 5
        Num handles: 1
        Handle: 1 Address: BB:22:33:44:55:99 (OUI BB-22-33)
        Count: 1
        #35: len 16 (25 Kb/s)
        Latency: 5 msec (2-7 msec ~4 msec)
< ACL Data TX: Handle 1 flags 0x00 dlen 16
      L2CAP: Connection Response (0x03) ident 3 len 8
        Destination CID: 64
        Source CID: 64
        Result: Connection successful (0x0000)
        Status: No further information available (0x0000)

Signed-off-by: Alex Lu <alex_lu@realsil.com.cn>
Signed-off-by: Max Chou <max.chou@realtek.com>
---
 net/bluetooth/l2cap_core.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

Comments

bluez.test.bot@gmail.com Dec. 11, 2023, 8:59 a.m. UTC | #1 
This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=808696

---Test result---

Test Summary:
CheckPatch                    PASS      0.52 seconds
GitLint                       PASS      0.24 seconds
SubjectPrefix                 PASS      0.19 seconds
BuildKernel                   PASS      27.94 seconds
CheckAllWarning               PASS      30.11 seconds
CheckSparse                   WARNING   36.38 seconds
CheckSmatch                   PASS      98.37 seconds
BuildKernel32                 PASS      26.50 seconds
TestRunnerSetup               PASS      425.18 seconds
TestRunner_l2cap-tester       PASS      23.09 seconds
TestRunner_iso-tester         PASS      44.69 seconds
TestRunner_bnep-tester        PASS      6.99 seconds
TestRunner_mgmt-tester        FAIL      168.41 seconds
TestRunner_rfcomm-tester      PASS      10.96 seconds
TestRunner_sco-tester         PASS      14.52 seconds
TestRunner_ioctl-tester       PASS      12.26 seconds
TestRunner_mesh-tester        PASS      8.79 seconds
TestRunner_smp-tester         PASS      10.18 seconds
TestRunner_userchan-tester    PASS      7.36 seconds
IncrementalBuild              PASS      25.61 seconds

Details
##############################
Test: CheckSparse - WARNING
Desc: Run sparse tool with linux kernel
Output:
net/bluetooth/l2cap_core.c:1676:52: warning: incorrect type in assignment (different base types)net/bluetooth/l2cap_core.c:1676:52:    expected restricted __le16 [assigned] [usertype] resultnet/bluetooth/l2cap_core.c:1676:52:    got int
##############################
Test: TestRunner_mgmt-tester - FAIL
Desc: Run mgmt-tester with test-runner
Output:
Total: 497, Passed: 496 (99.8%), Failed: 1, Not Run: 0

Failed Test Cases
LL Privacy - Start Discovery 2 (Disable RL)          Failed       0.289 seconds


---
Regards,
Linux Bluetooth
diff mbox series

Patch

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 17ca13e8c044..b0f31d798132 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1669,7 +1669,13 @@  static void l2cap_conn_start(struct l2cap_conn *conn)
 			rsp.dcid = cpu_to_le16(chan->scid);
 
 			if (l2cap_chan_check_security(chan, false)) {
-				if (test_bit(FLAG_DEFER_SETUP, &chan->flags)) {
+				if (!l2cap_check_enc_key_size(conn->hcon)) {
+					l2cap_state_change(chan, BT_DISCONN);
+					__set_chan_timer(chan,
+							 L2CAP_DISC_TIMEOUT);
+					rsp.result = L2CAP_CR_SEC_BLOCK;
+					rsp.status = L2CAP_CS_NO_INFO;
+				} else if (test_bit(FLAG_DEFER_SETUP, &chan->flags)) {
 					rsp.result = cpu_to_le16(L2CAP_CR_PEND);
 					rsp.status = cpu_to_le16(L2CAP_CS_AUTHOR_PEND);
 					chan->ops->defer(chan);
@@ -4202,7 +4208,15 @@  static struct l2cap_chan *l2cap_connect(struct l2cap_conn *conn,
 
 	if (conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_DONE) {
 		if (l2cap_chan_check_security(chan, false)) {
-			if (test_bit(FLAG_DEFER_SETUP, &chan->flags)) {
+			/* As slave role, we should check the enc key size when
+			 * l2cap conn req is received.
+			 */
+			if (!l2cap_check_enc_key_size(conn->hcon)) {
+				l2cap_state_change(chan, BT_DISCONN);
+				__set_chan_timer(chan, L2CAP_DISC_TIMEOUT);
+				result = L2CAP_CR_SEC_BLOCK;
+				status = L2CAP_CS_NO_INFO;
+			} else if (test_bit(FLAG_DEFER_SETUP, &chan->flags)) {
 				l2cap_state_change(chan, BT_CONNECT2);
 				result = L2CAP_CR_PEND;
 				status = L2CAP_CS_AUTHOR_PEND;