[PATCH] Bluetooth: skip invalid hci_sync_conn_complete_evt

[PATCH] Bluetooth: skip invalid hci_sync_conn_complete_evt

[Desmond Cheong Zhi Xi]

Syzbot reported a corrupted list in kobject_add_internal [1]. This
happens when multiple HCI_EV_SYNC_CONN_COMPLETE event packets with
status 0 are sent for the same HCI connection. This causes us to
register the device more than once which corrupts the kset list.

To fix this, in hci_sync_conn_complete_evt, we check whether we're
trying to process the same HCI_EV_SYNC_CONN_COMPLETE event multiple
times for one connection. If that's the case, the event is invalid, so
we skip further processing and exit.

Link: https://syzkaller.appspot.com/bug?extid=66264bf2fd0476be7e6c [1]
Reported-by: syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com
Tested-by: syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
---
 net/bluetooth/hci_event.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 016b2999f219..091a92338492 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4373,6 +4373,8 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev,
 
 	switch (ev->status) {
 	case 0x00:
+		if (conn->state == BT_CONNECTED)
+			goto unlock;  /* Already connected, event not valid */
 		conn->handle = __le16_to_cpu(ev->handle);
 		conn->state  = BT_CONNECTED;
 		conn->type   = ev->link_type;
-- 
2.25.1

[PATCH] Bluetooth: skip invalid hci_sync_conn_complete_evt

[Desmond Cheong Zhi Xi]

Syzbot reported a corrupted list in kobject_add_internal [1]. This
happens when multiple HCI_EV_SYNC_CONN_COMPLETE event packets with
status 0 are sent for the same HCI connection. This causes us to
register the device more than once which corrupts the kset list.

To fix this, in hci_sync_conn_complete_evt, we check whether we're
trying to process the same HCI_EV_SYNC_CONN_COMPLETE event multiple
times for one connection. If that's the case, the event is invalid, so
we skip further processing and exit.

Link: https://syzkaller.appspot.com/bug?extid=66264bf2fd0476be7e6c [1]
Reported-by: syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com
Tested-by: syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
---
 net/bluetooth/hci_event.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 016b2999f219..091a92338492 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4373,6 +4373,8 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev,
 
 	switch (ev->status) {
 	case 0x00:
+		if (conn->state == BT_CONNECTED)
+			goto unlock;  /* Already connected, event not valid */
 		conn->handle = __le16_to_cpu(ev->handle);
 		conn->state  = BT_CONNECTED;
 		conn->type   = ev->link_type;
-- 
2.25.1

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RE: Bluetooth: skip invalid hci_sync_conn_complete_evt

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 2727 bytes --]

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=518861

---Test result---

Test Summary:
CheckPatch                    PASS      0.60 seconds
GitLint                       PASS      0.11 seconds
BuildKernel                   PASS      600.35 seconds
TestRunner: Setup             PASS      404.01 seconds
TestRunner: l2cap-tester      PASS      3.07 seconds
TestRunner: bnep-tester       PASS      2.17 seconds
TestRunner: mgmt-tester       PASS      33.84 seconds
TestRunner: rfcomm-tester     PASS      2.35 seconds
TestRunner: sco-tester        PASS      2.33 seconds
TestRunner: smp-tester        FAIL      2.36 seconds
TestRunner: userchan-tester   PASS      2.13 seconds

Details
##############################
Test: CheckPatch - PASS - 0.60 seconds
Run checkpatch.pl script with rule in .checkpatch.conf


##############################
Test: GitLint - PASS - 0.11 seconds
Run gitlint with rule in .gitlint


##############################
Test: BuildKernel - PASS - 600.35 seconds
Build Kernel with minimal configuration supports Bluetooth


##############################
Test: TestRunner: Setup - PASS - 404.01 seconds
Setup environment for running Test Runner


##############################
Test: TestRunner: l2cap-tester - PASS - 3.07 seconds
Run test-runner with l2cap-tester
Total: 40, Passed: 40 (100.0%), Failed: 0, Not Run: 0

##############################
Test: TestRunner: bnep-tester - PASS - 2.17 seconds
Run test-runner with bnep-tester
Total: 1, Passed: 1 (100.0%), Failed: 0, Not Run: 0

##############################
Test: TestRunner: mgmt-tester - PASS - 33.84 seconds
Run test-runner with mgmt-tester
Total: 448, Passed: 445 (99.3%), Failed: 0, Not Run: 3

##############################
Test: TestRunner: rfcomm-tester - PASS - 2.35 seconds
Run test-runner with rfcomm-tester
Total: 9, Passed: 9 (100.0%), Failed: 0, Not Run: 0

##############################
Test: TestRunner: sco-tester - PASS - 2.33 seconds
Run test-runner with sco-tester
Total: 8, Passed: 8 (100.0%), Failed: 0, Not Run: 0

##############################
Test: TestRunner: smp-tester - FAIL - 2.36 seconds
Run test-runner with smp-tester
Total: 8, Passed: 7 (87.5%), Failed: 1, Not Run: 0

Failed Test Cases
SMP Client - SC Request 2                            Failed       0.033 seconds

##############################
Test: TestRunner: userchan-tester - PASS - 2.13 seconds
Run test-runner with userchan-tester
Total: 3, Passed: 3 (100.0%), Failed: 0, Not Run: 0



---
Regards,
Linux Bluetooth


[-- Attachment #2: l2cap-tester.log --]
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[-- Attachment #3: bnep-tester.log --]
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[-- Attachment #4: mgmt-tester.log --]
[-- Type: application/octet-stream, Size: 616825 bytes --]

[-- Attachment #5: rfcomm-tester.log --]
[-- Type: application/octet-stream, Size: 11676 bytes --]

[-- Attachment #6: sco-tester.log --]
[-- Type: application/octet-stream, Size: 9912 bytes --]

[-- Attachment #7: smp-tester.log --]
[-- Type: application/octet-stream, Size: 11705 bytes --]

[-- Attachment #8: userchan-tester.log --]
[-- Type: application/octet-stream, Size: 5453 bytes --]

Re: [PATCH] Bluetooth: skip invalid hci_sync_conn_complete_evt

[Marcel Holtmann]

Hi Desmond,

> Syzbot reported a corrupted list in kobject_add_internal [1]. This
> happens when multiple HCI_EV_SYNC_CONN_COMPLETE event packets with
> status 0 are sent for the same HCI connection. This causes us to
> register the device more than once which corrupts the kset list.

and that is actually forbidden by the spec. So we need to complain loudly that such a device is misbehaving.

> To fix this, in hci_sync_conn_complete_evt, we check whether we're
> trying to process the same HCI_EV_SYNC_CONN_COMPLETE event multiple
> times for one connection. If that's the case, the event is invalid, so
> we skip further processing and exit.
> 
> Link: https://syzkaller.appspot.com/bug?extid=66264bf2fd0476be7e6c [1]
> Reported-by: syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com
> Tested-by: syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com
> Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
> ---
> net/bluetooth/hci_event.c | 2 ++
> 1 file changed, 2 insertions(+)
> 
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index 016b2999f219..091a92338492 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -4373,6 +4373,8 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev,
> 
> 	switch (ev->status) {
> 	case 0x00:
> +		if (conn->state == BT_CONNECTED)
> +			goto unlock;  /* Already connected, event not valid */

The comment has go above and be a lot more details since this is not expected behavior from valid hardware and we should add a bt_dev_err as well.

> 		conn->handle = __le16_to_cpu(ev->handle);
> 		conn->state  = BT_CONNECTED;
> 		conn->type   = ev->link_type;

Regards

Marcel

Re: [PATCH] Bluetooth: skip invalid hci_sync_conn_complete_evt

[Marcel Holtmann]

Hi Desmond,

> Syzbot reported a corrupted list in kobject_add_internal [1]. This
> happens when multiple HCI_EV_SYNC_CONN_COMPLETE event packets with
> status 0 are sent for the same HCI connection. This causes us to
> register the device more than once which corrupts the kset list.

and that is actually forbidden by the spec. So we need to complain loudly that such a device is misbehaving.

> To fix this, in hci_sync_conn_complete_evt, we check whether we're
> trying to process the same HCI_EV_SYNC_CONN_COMPLETE event multiple
> times for one connection. If that's the case, the event is invalid, so
> we skip further processing and exit.
> 
> Link: https://syzkaller.appspot.com/bug?extid=66264bf2fd0476be7e6c [1]
> Reported-by: syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com
> Tested-by: syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com
> Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
> ---
> net/bluetooth/hci_event.c | 2 ++
> 1 file changed, 2 insertions(+)
> 
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index 016b2999f219..091a92338492 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -4373,6 +4373,8 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev,
> 
> 	switch (ev->status) {
> 	case 0x00:
> +		if (conn->state == BT_CONNECTED)
> +			goto unlock;  /* Already connected, event not valid */

The comment has go above and be a lot more details since this is not expected behavior from valid hardware and we should add a bt_dev_err as well.

> 		conn->handle = __le16_to_cpu(ev->handle);
> 		conn->state  = BT_CONNECTED;
> 		conn->type   = ev->link_type;

Regards

Marcel

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Re: [PATCH] Bluetooth: skip invalid hci_sync_conn_complete_evt

[Desmond Cheong Zhi Xi]

On 22/7/21 10:39 pm, Marcel Holtmann wrote:
> Hi Desmond,
> 
>> Syzbot reported a corrupted list in kobject_add_internal [1]. This
>> happens when multiple HCI_EV_SYNC_CONN_COMPLETE event packets with
>> status 0 are sent for the same HCI connection. This causes us to
>> register the device more than once which corrupts the kset list.
> 
> and that is actually forbidden by the spec. So we need to complain loudly that such a device is misbehaving.
> 
>> To fix this, in hci_sync_conn_complete_evt, we check whether we're
>> trying to process the same HCI_EV_SYNC_CONN_COMPLETE event multiple
>> times for one connection. If that's the case, the event is invalid, so
>> we skip further processing and exit.
>>
>> Link: https://syzkaller.appspot.com/bug?extid=66264bf2fd0476be7e6c [1]
>> Reported-by: syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com
>> Tested-by: syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com
>> Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
>> ---
>> net/bluetooth/hci_event.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
>> index 016b2999f219..091a92338492 100644
>> --- a/net/bluetooth/hci_event.c
>> +++ b/net/bluetooth/hci_event.c
>> @@ -4373,6 +4373,8 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev,
>>
>> 	switch (ev->status) {
>> 	case 0x00:
>> +		if (conn->state == BT_CONNECTED)
>> +			goto unlock;  /* Already connected, event not valid */
> 
> The comment has go above and be a lot more details since this is not expected behavior from valid hardware and we should add a bt_dev_err as well.
> 

Hi Marcel,

Apologies for the delayed response.

Thanks for the feedback, I'll add more elaboration for the new check and 
add a bt_dev_err in a v2 patch.

>> 		conn->handle = __le16_to_cpu(ev->handle);
>> 		conn->state  = BT_CONNECTED;
>> 		conn->type   = ev->link_type;
> 
> Regards
> 
> Marcel
> 

Re: [PATCH] Bluetooth: skip invalid hci_sync_conn_complete_evt

[Desmond Cheong Zhi Xi]

On 22/7/21 10:39 pm, Marcel Holtmann wrote:
> Hi Desmond,
> 
>> Syzbot reported a corrupted list in kobject_add_internal [1]. This
>> happens when multiple HCI_EV_SYNC_CONN_COMPLETE event packets with
>> status 0 are sent for the same HCI connection. This causes us to
>> register the device more than once which corrupts the kset list.
> 
> and that is actually forbidden by the spec. So we need to complain loudly that such a device is misbehaving.
> 
>> To fix this, in hci_sync_conn_complete_evt, we check whether we're
>> trying to process the same HCI_EV_SYNC_CONN_COMPLETE event multiple
>> times for one connection. If that's the case, the event is invalid, so
>> we skip further processing and exit.
>>
>> Link: https://syzkaller.appspot.com/bug?extid=66264bf2fd0476be7e6c [1]
>> Reported-by: syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com
>> Tested-by: syzbot+66264bf2fd0476be7e6c@syzkaller.appspotmail.com
>> Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
>> ---
>> net/bluetooth/hci_event.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
>> index 016b2999f219..091a92338492 100644
>> --- a/net/bluetooth/hci_event.c
>> +++ b/net/bluetooth/hci_event.c
>> @@ -4373,6 +4373,8 @@ static void hci_sync_conn_complete_evt(struct hci_dev *hdev,
>>
>> 	switch (ev->status) {
>> 	case 0x00:
>> +		if (conn->state == BT_CONNECTED)
>> +			goto unlock;  /* Already connected, event not valid */
> 
> The comment has go above and be a lot more details since this is not expected behavior from valid hardware and we should add a bt_dev_err as well.
> 

Hi Marcel,

Apologies for the delayed response.

Thanks for the feedback, I'll add more elaboration for the new check and 
add a bt_dev_err in a v2 patch.

>> 		conn->handle = __le16_to_cpu(ev->handle);
>> 		conn->state  = BT_CONNECTED;
>> 		conn->type   = ev->link_type;
> 
> Regards
> 
> Marcel
> 

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