* [PATCH] Bluetooth: use hdev lock for accept_list and reject_list in conn req
@ 2022-04-04 0:34 Niels Dossche
2022-04-04 2:40 ` bluez.test.bot
2022-04-05 17:18 ` [PATCH] " Marcel Holtmann
0 siblings, 2 replies; 4+ messages in thread
From: Niels Dossche @ 2022-04-04 0:34 UTC (permalink / raw)
To: linux-bluetooth
Cc: Marcel Holtmann, Johan Hedberg, Luiz Augusto von Dentz, Niels Dossche
All accesses (both read and modifications) to
hdev->{accept,reject}_list are protected by hdev lock,
except the ones in hci_conn_request_evt. This can cause a race condition
in the form of a list corruption.
The solution is to protect these lists in hci_conn_request_evt as well.
I was unable to find the exact commit that introduced the issue for the
reject list, I was only able to find it for the accept list.
Note:
I am currently working on a static analyser to detect missing locks
using type-based static analysis as my master's thesis
in order to obtain my master's degree.
If you would like to have more details, please let me know.
This was a reported case. I manually verified the report by looking
at the code, so that I do not send wrong information or patches.
After concluding that this seems to be a true positive, I created
this patch. I have both compile-tested this patch and runtime-tested
this patch on x86_64. The effect on a running system could be a
potential race condition in exceptional cases.
This issue was found on Linux v5.17.1.
Fixes: a55bd29d5227 ("Bluetooth: Add white list lookup for incoming connection requests")
Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
---
net/bluetooth/hci_event.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index abaabfae19cc..b9038f24f46f 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -3222,8 +3222,11 @@ static void hci_conn_request_evt(struct hci_dev *hdev, void *data,
return;
}
+ hci_dev_lock(hdev);
+
if (hci_bdaddr_list_lookup(&hdev->reject_list, &ev->bdaddr,
BDADDR_BREDR)) {
+ hci_dev_unlock(hdev);
hci_reject_conn(hdev, &ev->bdaddr);
return;
}
@@ -3236,14 +3239,13 @@ static void hci_conn_request_evt(struct hci_dev *hdev, void *data,
!hci_dev_test_flag(hdev, HCI_CONNECTABLE) &&
!hci_bdaddr_list_lookup_with_flags(&hdev->accept_list, &ev->bdaddr,
BDADDR_BREDR)) {
+ hci_dev_unlock(hdev);
hci_reject_conn(hdev, &ev->bdaddr);
return;
}
/* Connection accepted */
- hci_dev_lock(hdev);
-
ie = hci_inquiry_cache_lookup(hdev, &ev->bdaddr);
if (ie)
memcpy(ie->data.dev_class, ev->dev_class, 3);
--
2.35.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* RE: Bluetooth: use hdev lock for accept_list and reject_list in conn req
2022-04-04 0:34 [PATCH] Bluetooth: use hdev lock for accept_list and reject_list in conn req Niels Dossche
@ 2022-04-04 2:40 ` bluez.test.bot
2022-04-05 17:18 ` [PATCH] " Marcel Holtmann
1 sibling, 0 replies; 4+ messages in thread
From: bluez.test.bot @ 2022-04-04 2:40 UTC (permalink / raw)
To: linux-bluetooth, dossche.niels
[-- Attachment #1: Type: text/plain, Size: 1096 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=628619
---Test result---
Test Summary:
CheckPatch PASS 1.54 seconds
GitLint PASS 1.01 seconds
SubjectPrefix PASS 0.89 seconds
BuildKernel PASS 30.05 seconds
BuildKernel32 PASS 27.33 seconds
Incremental Build with patchesPASS 38.38 seconds
TestRunner: Setup PASS 458.46 seconds
TestRunner: l2cap-tester PASS 15.27 seconds
TestRunner: bnep-tester PASS 6.04 seconds
TestRunner: mgmt-tester PASS 99.50 seconds
TestRunner: rfcomm-tester PASS 7.31 seconds
TestRunner: sco-tester PASS 7.24 seconds
TestRunner: smp-tester PASS 6.75 seconds
TestRunner: userchan-tester PASS 5.87 seconds
---
Regards,
Linux Bluetooth
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Bluetooth: use hdev lock for accept_list and reject_list in conn req
2022-04-04 0:34 [PATCH] Bluetooth: use hdev lock for accept_list and reject_list in conn req Niels Dossche
2022-04-04 2:40 ` bluez.test.bot
@ 2022-04-05 17:18 ` Marcel Holtmann
2022-04-05 17:20 ` Niels Dossche
1 sibling, 1 reply; 4+ messages in thread
From: Marcel Holtmann @ 2022-04-05 17:18 UTC (permalink / raw)
To: Niels Dossche; +Cc: linux-bluetooth, Johan Hedberg, Luiz Augusto von Dentz
Hi Niels,
> All accesses (both read and modifications) to
> hdev->{accept,reject}_list are protected by hdev lock,
> except the ones in hci_conn_request_evt. This can cause a race condition
> in the form of a list corruption.
> The solution is to protect these lists in hci_conn_request_evt as well.
>
> I was unable to find the exact commit that introduced the issue for the
> reject list, I was only able to find it for the accept list.
>
> Note:
> I am currently working on a static analyser to detect missing locks
> using type-based static analysis as my master's thesis
> in order to obtain my master's degree.
> If you would like to have more details, please let me know.
> This was a reported case. I manually verified the report by looking
> at the code, so that I do not send wrong information or patches.
> After concluding that this seems to be a true positive, I created
> this patch. I have both compile-tested this patch and runtime-tested
> this patch on x86_64. The effect on a running system could be a
> potential race condition in exceptional cases.
> This issue was found on Linux v5.17.1.
this doesn’t belong in the commit message.
>
> Fixes: a55bd29d5227 ("Bluetooth: Add white list lookup for incoming connection requests")
> Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
> ---
> net/bluetooth/hci_event.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index abaabfae19cc..b9038f24f46f 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -3222,8 +3222,11 @@ static void hci_conn_request_evt(struct hci_dev *hdev, void *data,
> return;
> }
>
> + hci_dev_lock(hdev);
> +
> if (hci_bdaddr_list_lookup(&hdev->reject_list, &ev->bdaddr,
> BDADDR_BREDR)) {
> + hci_dev_unlock(hdev);
> hci_reject_conn(hdev, &ev->bdaddr);
> return;
> }
> @@ -3236,14 +3239,13 @@ static void hci_conn_request_evt(struct hci_dev *hdev, void *data,
> !hci_dev_test_flag(hdev, HCI_CONNECTABLE) &&
> !hci_bdaddr_list_lookup_with_flags(&hdev->accept_list, &ev->bdaddr,
> BDADDR_BREDR)) {
> + hci_dev_unlock(hdev);
> hci_reject_conn(hdev, &ev->bdaddr);
> return;
> }
Can we use an exit goto-label instead. I am not a big fan of "unbalanced” _unlock statements.
> /* Connection accepted */
>
> - hci_dev_lock(hdev);
> -
> ie = hci_inquiry_cache_lookup(hdev, &ev->bdaddr);
> if (ie)
> memcpy(ie->data.dev_class, ev->dev_class, 3);
Regards
Marcel
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Bluetooth: use hdev lock for accept_list and reject_list in conn req
2022-04-05 17:18 ` [PATCH] " Marcel Holtmann
@ 2022-04-05 17:20 ` Niels Dossche
0 siblings, 0 replies; 4+ messages in thread
From: Niels Dossche @ 2022-04-05 17:20 UTC (permalink / raw)
To: Marcel Holtmann; +Cc: linux-bluetooth, Johan Hedberg, Luiz Augusto von Dentz
On 05/04/2022 19:18, Marcel Holtmann wrote:
> Hi Niels,
>
>> All accesses (both read and modifications) to
>> hdev->{accept,reject}_list are protected by hdev lock,
>> except the ones in hci_conn_request_evt. This can cause a race condition
>> in the form of a list corruption.
>> The solution is to protect these lists in hci_conn_request_evt as well.
>>
>> I was unable to find the exact commit that introduced the issue for the
>> reject list, I was only able to find it for the accept list.
>>
>> Note:
>> I am currently working on a static analyser to detect missing locks
>> using type-based static analysis as my master's thesis
>> in order to obtain my master's degree.
>> If you would like to have more details, please let me know.
>> This was a reported case. I manually verified the report by looking
>> at the code, so that I do not send wrong information or patches.
>> After concluding that this seems to be a true positive, I created
>> this patch. I have both compile-tested this patch and runtime-tested
>> this patch on x86_64. The effect on a running system could be a
>> potential race condition in exceptional cases.
>> This issue was found on Linux v5.17.1.
>
> this doesn’t belong in the commit message.
Hi Marcel
I'll remove it from the commit message.
I can write it in below the --- in the future such that it won't be included.
>
>>
>> Fixes: a55bd29d5227 ("Bluetooth: Add white list lookup for incoming connection requests")
>> Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
>> ---
>> net/bluetooth/hci_event.c | 6 ++++--
>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
>> index abaabfae19cc..b9038f24f46f 100644
>> --- a/net/bluetooth/hci_event.c
>> +++ b/net/bluetooth/hci_event.c
>> @@ -3222,8 +3222,11 @@ static void hci_conn_request_evt(struct hci_dev *hdev, void *data,
>> return;
>> }
>>
>> + hci_dev_lock(hdev);
>> +
>> if (hci_bdaddr_list_lookup(&hdev->reject_list, &ev->bdaddr,
>> BDADDR_BREDR)) {
>> + hci_dev_unlock(hdev);
>> hci_reject_conn(hdev, &ev->bdaddr);
>> return;
>> }
>> @@ -3236,14 +3239,13 @@ static void hci_conn_request_evt(struct hci_dev *hdev, void *data,
>> !hci_dev_test_flag(hdev, HCI_CONNECTABLE) &&
>> !hci_bdaddr_list_lookup_with_flags(&hdev->accept_list, &ev->bdaddr,
>> BDADDR_BREDR)) {
>> + hci_dev_unlock(hdev);
>> hci_reject_conn(hdev, &ev->bdaddr);
>> return;
>> }
>
> Can we use an exit goto-label instead. I am not a big fan of "unbalanced” _unlock statements.
I'll make a v2 and send it.
>
>> /* Connection accepted */
>>
>> - hci_dev_lock(hdev);
>> -
>> ie = hci_inquiry_cache_lookup(hdev, &ev->bdaddr);
>> if (ie)
>> memcpy(ie->data.dev_class, ev->dev_class, 3);
>
> Regards
>
> Marcel
>
Thanks
Niels
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-04-06 0:44 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2022-04-04 0:34 [PATCH] Bluetooth: use hdev lock for accept_list and reject_list in conn req Niels Dossche
2022-04-04 2:40 ` bluez.test.bot
2022-04-05 17:18 ` [PATCH] " Marcel Holtmann
2022-04-05 17:20 ` Niels Dossche
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