[PATCH] Bluetooth: add timeout sanity check to hci_inquiry

[PATCH] Bluetooth: add timeout sanity check to hci_inquiry

[Pavel Skripkin]

Syzbot hit "task hung" bug in hci_req_sync(). The problem was in
unreasonable huge inquiry timeout passed from userspace.
Fix it by adding sanity check for timeout value and add constant to
hsi_sock.h to inform userspace, that hci_inquiry_req::length field has
maximum possible value.

Since hci_inquiry() is the only user of hci_req_sync() with user
controlled timeout value, it makes sense to check timeout value in
hci_inquiry() and don't touch hci_req_sync().

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-and-tested-by: syzbot+be2baed593ea56c6a84c@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---

Hi, Bluetooth maintainers/reviewers!

I believe, 60 seconds will be more than enough for inquiry request. I've
searched for examples on the internet and maximum ir.length I found was 
8. Maybe, we have users, which need more than 60 seconds... I look forward
to receiving your views on this value.

---
 include/net/bluetooth/hci_sock.h | 1 +
 net/bluetooth/hci_core.c         | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/include/net/bluetooth/hci_sock.h b/include/net/bluetooth/hci_sock.h
index 9949870f7d78..1cd63d4da00b 100644
--- a/include/net/bluetooth/hci_sock.h
+++ b/include/net/bluetooth/hci_sock.h
@@ -168,6 +168,7 @@ struct hci_inquiry_req {
 	__u16 dev_id;
 	__u16 flags;
 	__u8  lap[3];
+#define HCI_INQUIRY_MAX_TIMEOUT		30
 	__u8  length;
 	__u8  num_rsp;
 };
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index e1a545c8a69f..104babf67351 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1343,6 +1343,11 @@ int hci_inquiry(void __user *arg)
 		goto done;
 	}
 
+	if (ir.length > HCI_INQUIRY_MAX_TIMEOUT) {
+		err = -EINVAL;
+		goto done;
+	}
+
 	hci_dev_lock(hdev);
 	if (inquiry_cache_age(hdev) > INQUIRY_CACHE_AGE_MAX ||
 	    inquiry_cache_empty(hdev) || ir.flags & IREQ_CACHE_FLUSH) {
-- 
2.32.0

RE: Bluetooth: add timeout sanity check to hci_inquiry

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 3489 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=532679

---Test result---

Test Summary:
CheckPatch                    FAIL      0.57 seconds
GitLint                       PASS      0.11 seconds
BuildKernel                   PASS      513.85 seconds
TestRunner: Setup             PASS      336.43 seconds
TestRunner: l2cap-tester      PASS      2.60 seconds
TestRunner: bnep-tester       PASS      1.84 seconds
TestRunner: mgmt-tester       PASS      30.71 seconds
TestRunner: rfcomm-tester     PASS      1.95 seconds
TestRunner: sco-tester        PASS      1.94 seconds
TestRunner: smp-tester        FAIL      1.99 seconds
TestRunner: userchan-tester   PASS      1.89 seconds

Details
##############################
Test: CheckPatch - FAIL - 0.57 seconds
Run checkpatch.pl script with rule in .checkpatch.conf
Bluetooth: add timeout sanity check to hci_inquiry
WARNING: Unknown commit id '1da177e4c3f4', maybe rebased or not pulled?
#16: 
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")

WARNING: Possible unwrapped commit description (prefer a maximum 75 chars per line)
#17: 
Reported-and-tested-by: syzbot+be2baed593ea56c6a84c@syzkaller.appspotmail.com

total: 0 errors, 2 warnings, 0 checks, 18 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

"[PATCH] Bluetooth: add timeout sanity check to hci_inquiry" has style problems, please review.

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.


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


##############################
Test: BuildKernel - PASS - 513.85 seconds
Build Kernel with minimal configuration supports Bluetooth


##############################
Test: TestRunner: Setup - PASS - 336.43 seconds
Setup environment for running Test Runner


##############################
Test: TestRunner: l2cap-tester - PASS - 2.60 seconds
Run test-runner with l2cap-tester
Total: 40, Passed: 40 (100.0%), Failed: 0, Not Run: 0

##############################
Test: TestRunner: bnep-tester - PASS - 1.84 seconds
Run test-runner with bnep-tester
Total: 1, Passed: 1 (100.0%), Failed: 0, Not Run: 0

##############################
Test: TestRunner: mgmt-tester - PASS - 30.71 seconds
Run test-runner with mgmt-tester
Total: 448, Passed: 445 (99.3%), Failed: 0, Not Run: 3

##############################
Test: TestRunner: rfcomm-tester - PASS - 1.95 seconds
Run test-runner with rfcomm-tester
Total: 9, Passed: 9 (100.0%), Failed: 0, Not Run: 0

##############################
Test: TestRunner: sco-tester - PASS - 1.94 seconds
Run test-runner with sco-tester
Total: 8, Passed: 8 (100.0%), Failed: 0, Not Run: 0

##############################
Test: TestRunner: smp-tester - FAIL - 1.99 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       0.020 seconds

##############################
Test: TestRunner: userchan-tester - PASS - 1.89 seconds
Run test-runner with userchan-tester
Total: 3, Passed: 3 (100.0%), Failed: 0, Not Run: 0



---
Regards,
Linux Bluetooth


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[-- Attachment #6: sco-tester.log --]
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Re: [PATCH] Bluetooth: add timeout sanity check to hci_inquiry

[Marcel Holtmann]

Hi Pavel,

> Syzbot hit "task hung" bug in hci_req_sync(). The problem was in
> unreasonable huge inquiry timeout passed from userspace.
> Fix it by adding sanity check for timeout value and add constant to
> hsi_sock.h to inform userspace, that hci_inquiry_req::length field has
> maximum possible value.
> 
> Since hci_inquiry() is the only user of hci_req_sync() with user
> controlled timeout value, it makes sense to check timeout value in
> hci_inquiry() and don't touch hci_req_sync().
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Reported-and-tested-by: syzbot+be2baed593ea56c6a84c@syzkaller.appspotmail.com
> Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
> ---
> 
> Hi, Bluetooth maintainers/reviewers!
> 
> I believe, 60 seconds will be more than enough for inquiry request. I've
> searched for examples on the internet and maximum ir.length I found was 
> 8. Maybe, we have users, which need more than 60 seconds... I look forward
> to receiving your views on this value.
> 
> ---
> include/net/bluetooth/hci_sock.h | 1 +
> net/bluetooth/hci_core.c         | 5 +++++
> 2 files changed, 6 insertions(+)
> 
> diff --git a/include/net/bluetooth/hci_sock.h b/include/net/bluetooth/hci_sock.h
> index 9949870f7d78..1cd63d4da00b 100644
> --- a/include/net/bluetooth/hci_sock.h
> +++ b/include/net/bluetooth/hci_sock.h
> @@ -168,6 +168,7 @@ struct hci_inquiry_req {
> 	__u16 dev_id;
> 	__u16 flags;
> 	__u8  lap[3];
> +#define HCI_INQUIRY_MAX_TIMEOUT		30
> 	__u8  length;
> 	__u8  num_rsp;
> };
> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> index e1a545c8a69f..104babf67351 100644
> --- a/net/bluetooth/hci_core.c
> +++ b/net/bluetooth/hci_core.c
> @@ -1343,6 +1343,11 @@ int hci_inquiry(void __user *arg)
> 		goto done;
> 	}
> 

	/* Restrict maximum inquiry length to 60 seconds */
	if (ir.length > 60) {
		..
	}

> +	if (ir.length > HCI_INQUIRY_MAX_TIMEOUT) {
> +		err = -EINVAL;
> +		goto done;
> +	}
> +

I found this easier to read than adding anything define somewhere else. And since this is a legacy interface that is no longer used by bluetoothd, this should be fine. We will start to deprecate this eventually.

And I prefer 1 minute max time here. Just to be safe.

Regards

Marcel

Re: [PATCH] Bluetooth: add timeout sanity check to hci_inquiry

[Pavel Skripkin]

On 8/19/21 6:05 PM, Marcel Holtmann wrote:
> Hi Pavel,
> 
>> 	}
>> 
> 
> 	/* Restrict maximum inquiry length to 60 seconds */
> 	if (ir.length > 60) {
> 		..
> 	}
> 
>> +	if (ir.length > HCI_INQUIRY_MAX_TIMEOUT) {
>> +		err = -EINVAL;
>> +		goto done;
>> +	}
>> +
> 
> I found this easier to read than adding anything define somewhere else. And since this is a legacy interface that is no longer used by bluetoothd, this should be fine. We will start to deprecate this eventually.
> 
> And I prefer 1 minute max time here. Just to be safe.
> 

I thought, that user-space should be aware of maximum value, that's why 
I decided to add this define :) I didn't know, that this interface is 
legacy.

Will fix in v2, thank you!


With regards,
Pavel Skripkin

[PATCH v2] Bluetooth: add timeout sanity check to hci_inquiry

[Pavel Skripkin]

Syzbot hit "task hung" bug in hci_req_sync(). The problem was in
unreasonable huge inquiry timeout passed from userspace.
Fix it by adding sanity check for timeout value to hci_inquiry().

Since hci_inquiry() is the only user of hci_req_sync() with user
controlled timeout value, it makes sense to check timeout value in
hci_inquiry() and don't touch hci_req_sync().

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-and-tested-by: syzbot+be2baed593ea56c6a84c@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---

Changes in v2:
	Removed define + added comment suggested by Marcel

---
 net/bluetooth/hci_core.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index e1a545c8a69f..170f513efa86 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1343,6 +1343,12 @@ int hci_inquiry(void __user *arg)
 		goto done;
 	}
 
+	/* Restrict maximum inquiry length to 60 seconds */
+	if (ir.length > 60) {
+		err = -EINVAL;
+		goto done;
+	}
+
 	hci_dev_lock(hdev);
 	if (inquiry_cache_age(hdev) > INQUIRY_CACHE_AGE_MAX ||
 	    inquiry_cache_empty(hdev) || ir.flags & IREQ_CACHE_FLUSH) {
-- 
2.32.0

Re: [PATCH v2] Bluetooth: add timeout sanity check to hci_inquiry

[Marcel Holtmann]

Hi Pavel,

> Syzbot hit "task hung" bug in hci_req_sync(). The problem was in
> unreasonable huge inquiry timeout passed from userspace.
> Fix it by adding sanity check for timeout value to hci_inquiry().
> 
> Since hci_inquiry() is the only user of hci_req_sync() with user
> controlled timeout value, it makes sense to check timeout value in
> hci_inquiry() and don't touch hci_req_sync().
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Reported-and-tested-by: syzbot+be2baed593ea56c6a84c@syzkaller.appspotmail.com
> Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
> ---
> 
> Changes in v2:
> 	Removed define + added comment suggested by Marcel
> 
> ---
> net/bluetooth/hci_core.c | 6 ++++++
> 1 file changed, 6 insertions(+)

patch has been applied to bluetooth-next tree.

Regards

Marcel

RE: [v2] Bluetooth: add timeout sanity check to hci_inquiry

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 3489 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=534245

---Test result---

Test Summary:
CheckPatch                    FAIL      0.45 seconds
GitLint                       PASS      0.10 seconds
BuildKernel                   PASS      500.56 seconds
TestRunner: Setup             PASS      326.35 seconds
TestRunner: l2cap-tester      PASS      2.53 seconds
TestRunner: bnep-tester       PASS      1.90 seconds
TestRunner: mgmt-tester       PASS      30.57 seconds
TestRunner: rfcomm-tester     PASS      2.00 seconds
TestRunner: sco-tester        PASS      2.01 seconds
TestRunner: smp-tester        FAIL      2.02 seconds
TestRunner: userchan-tester   PASS      1.92 seconds

Details
##############################
Test: CheckPatch - FAIL - 0.45 seconds
Run checkpatch.pl script with rule in .checkpatch.conf
Bluetooth: add timeout sanity check to hci_inquiry
WARNING: Unknown commit id '1da177e4c3f4', maybe rebased or not pulled?
#14: 
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")

WARNING: Possible unwrapped commit description (prefer a maximum 75 chars per line)
#15: 
Reported-and-tested-by: syzbot+be2baed593ea56c6a84c@syzkaller.appspotmail.com

total: 0 errors, 2 warnings, 0 checks, 12 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

"[PATCH] Bluetooth: add timeout sanity check to hci_inquiry" has style problems, please review.

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.


##############################
Test: GitLint - PASS - 0.10 seconds
Run gitlint with rule in .gitlint


##############################
Test: BuildKernel - PASS - 500.56 seconds
Build Kernel with minimal configuration supports Bluetooth


##############################
Test: TestRunner: Setup - PASS - 326.35 seconds
Setup environment for running Test Runner


##############################
Test: TestRunner: l2cap-tester - PASS - 2.53 seconds
Run test-runner with l2cap-tester
Total: 40, Passed: 40 (100.0%), Failed: 0, Not Run: 0

##############################
Test: TestRunner: bnep-tester - PASS - 1.90 seconds
Run test-runner with bnep-tester
Total: 1, Passed: 1 (100.0%), Failed: 0, Not Run: 0

##############################
Test: TestRunner: mgmt-tester - PASS - 30.57 seconds
Run test-runner with mgmt-tester
Total: 448, Passed: 445 (99.3%), Failed: 0, Not Run: 3

##############################
Test: TestRunner: rfcomm-tester - PASS - 2.00 seconds
Run test-runner with rfcomm-tester
Total: 9, Passed: 9 (100.0%), Failed: 0, Not Run: 0

##############################
Test: TestRunner: sco-tester - PASS - 2.01 seconds
Run test-runner with sco-tester
Total: 8, Passed: 8 (100.0%), Failed: 0, Not Run: 0

##############################
Test: TestRunner: smp-tester - FAIL - 2.02 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       0.020 seconds

##############################
Test: TestRunner: userchan-tester - PASS - 1.92 seconds
Run test-runner with userchan-tester
Total: 3, Passed: 3 (100.0%), Failed: 0, Not Run: 0



---
Regards,
Linux Bluetooth


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[-- Attachment #6: sco-tester.log --]
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