[PATCH] Bluetooth: hci_sock: validate event length before filtering

[PATCH] Bluetooth: hci_sock: validate event length before filtering

[Aldo Ariel Panzardo]

is_filtered_packet() reads the event code from skb->data[0] without first
checking that the skb is nonempty. When an opcode filter is configured,
it also reads the command opcode at offsets 3 or 4 without checking that
a Command Complete or Command Status event is long enough.

hci_send_to_sock() invokes the filter before hci_event_packet() validates
the event header. A malformed event supplied by a controller or a vhci
device can therefore cause an out-of-bounds read.

Keep the unmasked event code for the opcode checks. The masked value is
needed for the 64-bit event bitmap, but using it to identify command events
aliases event codes above 0x3f. In particular, Synchronous Train Complete
(0x4f) was treated as Command Status (0x0f) even though its payload has no
opcode.

Reject actual command events that are too short for the field being
inspected. A truncated command event cannot match a configured opcode.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Aldo Ariel Panzardo <qwe.aldo@gmail.com>
---
 net/bluetooth/hci_sock.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index 070ca388f..f6406dcec 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -164,6 +164,7 @@ static bool is_filtered_packet(struct sock *sk, struct sk_buff *skb)
 {
 	struct hci_filter *flt;
 	int flt_type, flt_event;
+	u8 event;
 
 	/* Apply filter */
 	flt = &hci_pi(sk)->filter;
@@ -177,7 +178,11 @@ static bool is_filtered_packet(struct sock *sk, struct sk_buff *skb)
 	if (hci_skb_pkt_type(skb) != HCI_EVENT_PKT)
 		return false;
 
-	flt_event = (*(__u8 *)skb->data & HCI_FLT_EVENT_BITS);
+	if (skb->len < 1)
+		return true;
+
+	event = *(__u8 *)skb->data;
+	flt_event = event & HCI_FLT_EVENT_BITS;
 
 	if (!hci_test_bit(flt_event, &flt->event_mask))
 		return true;
@@ -186,11 +191,17 @@ static bool is_filtered_packet(struct sock *sk, struct sk_buff *skb)
 	if (!flt->opcode)
 		return false;
 
-	if (flt_event == HCI_EV_CMD_COMPLETE &&
+	if (event == HCI_EV_CMD_COMPLETE && skb->len < 5)
+		return true;
+
+	if (event == HCI_EV_CMD_COMPLETE &&
 	    flt->opcode != get_unaligned((__le16 *)(skb->data + 3)))
 		return true;
 
-	if (flt_event == HCI_EV_CMD_STATUS &&
+	if (event == HCI_EV_CMD_STATUS && skb->len < 6)
+		return true;
+
+	if (event == HCI_EV_CMD_STATUS &&
 	    flt->opcode != get_unaligned((__le16 *)(skb->data + 4)))
 		return true;
 
-- 
2.43.0

RE: Bluetooth: hci_sock: validate event length before filtering

[bluez.test.bot]

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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/series/1165735/

---Test result---

Test Summary:
CheckPatch                    PASS      1.40 seconds
VerifyFixes                   PASS      0.09 seconds
VerifySignedoff               PASS      0.09 seconds
GitLint                       PASS      0.24 seconds
SubjectPrefix                 PASS      0.09 seconds
BuildKernel                   PASS      19.67 seconds
CheckAllWarning               PASS      24.44 seconds
CheckSparse                   PASS      24.92 seconds
BuildKernel32                 PASS      21.20 seconds
CheckKernelLLVM               PASS      20.79 seconds
TestRunnerSetup               PASS      504.73 seconds
TestRunner_l2cap-tester       FAIL      10.09 seconds
TestRunner_iso-tester         FAIL      5.83 seconds
TestRunner_bnep-tester        FAIL      5.90 seconds
TestRunner_mgmt-tester        FAIL      5.89 seconds
TestRunner_rfcomm-tester      FAIL      5.68 seconds
TestRunner_sco-tester         FAIL      5.88 seconds
TestRunner_ioctl-tester       FAIL      5.70 seconds
TestRunner_mesh-tester        FAIL      5.76 seconds
TestRunner_smp-tester         FAIL      5.70 seconds
TestRunner_userchan-tester    FAIL      5.90 seconds
TestRunner_6lowpan-tester     FAIL      5.81 seconds
IncrementalBuild              PASS      19.58 seconds

Details
##############################
Test: TestRunner_l2cap-tester - FAIL
Desc: Run l2cap-tester with test-runner
Output:
No test result found
##############################
Test: TestRunner_iso-tester - FAIL
Desc: Run iso-tester with test-runner
Output:
No test result found
##############################
Test: TestRunner_bnep-tester - FAIL
Desc: Run bnep-tester with test-runner
Output:
No test result found
##############################
Test: TestRunner_mgmt-tester - FAIL
Desc: Run mgmt-tester with test-runner
Output:
No test result found
##############################
Test: TestRunner_rfcomm-tester - FAIL
Desc: Run rfcomm-tester with test-runner
Output:
No test result found
##############################
Test: TestRunner_sco-tester - FAIL
Desc: Run sco-tester with test-runner
Output:
No test result found
##############################
Test: TestRunner_ioctl-tester - FAIL
Desc: Run ioctl-tester with test-runner
Output:
No test result found
##############################
Test: TestRunner_mesh-tester - FAIL
Desc: Run mesh-tester with test-runner
Output:
No test result found
##############################
Test: TestRunner_smp-tester - FAIL
Desc: Run smp-tester with test-runner
Output:
No test result found
##############################
Test: TestRunner_userchan-tester - FAIL
Desc: Run userchan-tester with test-runner
Output:
No test result found
##############################
Test: TestRunner_6lowpan-tester - FAIL
Desc: Run 6lowpan-tester with test-runner
Output:
No test result found


https://github.com/bluez/bluetooth-next/pull/775

---
Regards,
Linux Bluetooth

Re: [PATCH] Bluetooth: hci_sock: validate event length before filtering

[patchwork-bot+bluetooth]

Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Tue, 15 Sep 2026 13:03:07 -0300 you wrote:
> is_filtered_packet() reads the event code from skb->data[0] without first
> checking that the skb is nonempty. When an opcode filter is configured,
> it also reads the command opcode at offsets 3 or 4 without checking that
> a Command Complete or Command Status event is long enough.
> 
> hci_send_to_sock() invokes the filter before hci_event_packet() validates
> the event header. A malformed event supplied by a controller or a vhci
> device can therefore cause an out-of-bounds read.
> 
> [...]

Here is the summary with links:
  - Bluetooth: hci_sock: validate event length before filtering
    https://git.kernel.org/bluetooth/bluetooth-next/c/b0a6cf99afd5

You are awesome, thank you!
-- 
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