diff mbox series

[v2] Bluetooth: L2CAP: Fix div-by-zero in l2cap_le_flowctl_init()

Message ID 20240501042936.2579739-1-iam@sung-woo.kim (mailing list archive)
State Superseded
Headers show
Series [v2] Bluetooth: L2CAP: Fix div-by-zero in l2cap_le_flowctl_init() | expand

Checks

Context Check Description
tedd_an/pre-ci_am success Success
tedd_an/CheckPatch warning WARNING: Prefer a maximum 75 chars per line (possible unwrapped commit description?) #122: CPU: 0 PID: 67 Comm: kworker/u5:0 Tainted: G W 6.9.0-rc5+ #20 total: 0 errors, 1 warnings, 0 checks, 40 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. /github/workspace/src/src/13650236.patch has style problems, please review. NOTE: Ignored message types: UNKNOWN_COMMIT_ID NOTE: If any of the errors are false positives, please report them to the maintainer, see CHECKPATCH in MAINTAINERS.
tedd_an/GitLint fail WARNING: I3 - ignore-body-lines: gitlint will be switching from using Python regex 'match' (match beginning) to 'search' (match anywhere) semantics. Please review your ignore-body-lines.regex option accordingly. To remove this warning, set general.regex-style-search=True. More details: https://jorisroovers.github.io/gitlint/configuration/#regex-style-search 44: B1 Line exceeds max length (199>80): "Code: e8 17 17 0c 00 66 41 89 9f 84 00 00 00 bf 01 00 00 00 41 b8 02 00 00 00 4c 89 fe 4c 89 e2 89 d9 e8 27 17 0c 00 44 89 f0 31 d2 <66> f7 f3 89 c3 ff c3 4d 8d b7 88 00 00 00 4c 89 f0 48 c1 e8 03 42"
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/hci_event.c: note: in included file (through include/net/bluetooth/hci_core.h):
tedd_an/CheckSmatch fail CheckSparse: FAIL: Segmentation fault (core dumped) make[4]: *** [scripts/Makefile.build:244: net/bluetooth/hci_core.o] Error 139 make[4]: *** Deleting file 'net/bluetooth/hci_core.o' make[3]: *** [scripts/Makefile.build:485: net/bluetooth] Error 2 make[2]: *** [scripts/Makefile.build:485: net] Error 2 make[2]: *** Waiting for unfinished jobs.... Segmentation fault (core dumped) make[4]: *** [scripts/Makefile.build:244: drivers/bluetooth/bcm203x.o] Error 139 make[4]: *** Deleting file 'drivers/bluetooth/bcm203x.o' make[4]: *** Waiting for unfinished jobs.... Segmentation fault (core dumped) make[4]: *** [scripts/Makefile.build:244: drivers/bluetooth/bpa10x.o] Error 139 make[4]: *** Deleting file 'drivers/bluetooth/bpa10x.o' make[3]: *** [scripts/Makefile.build:485: drivers/bluetooth] Error 2 make[2]: *** [scripts/Makefile.build:485: drivers] Error 2 make[1]: *** [/github/workspace/src/src/Makefile:1919: .] Error 2 make: *** [Makefile:240: __sub-make] Error 2
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: 492, Passed: 489 (99.4%), Failed: 1, Not Run: 2
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 fail TestRunner_mesh-tester: Total: 10, Passed: 9 (90.0%), Failed: 1, Not Run: 0
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

Sungwoo Kim May 1, 2024, 4:29 a.m. UTC
Hi Luiz, could you review this patch?

This patch prevents a div-by-zero error and potential int overflow by
adding a range check for MTU in hci_cc_le_read_buffer_size() and
hci_cc_le_read_buffer_size_v2().
Also, hci_connect_le() will refuse to allocate hcon if the MTU is not in
the valid range.

Bug description:

l2cap_le_flowctl_init() can cause both div-by-zero and an integer overflow.

l2cap_le_flowctl_init()
  chan->mps = min_t(u16, chan->imtu, chan->conn->mtu - L2CAP_HDR_SIZE);
  chan->rx_credits = (chan->imtu / chan->mps) + 1;  <- div-by-zero

Here, chan->conn->mtu could be less than or equal to L2CAP_HDR_SIZE (4).
If mtu is 4, it causes div-by-zero. If mtu is less than 4, it causes an
integer overflow.

How mtu could have such low value:

hci_cc_le_read_buffer_size()
  hdev->le_mtu = __le16_to_cpu(rp->le_mtu);

l2cap_conn_add()
  conn->mtu = hcon->hdev->le_mtu;

As shown, mtu is an input from an HCI device. So, any HCI device can
set mtu value to any value, such as lower than 4.
According to the spec v5.4 7.8.2 LE Read Buffer Size command, the value
should be fall in [0x001b, 0xffff].

Thank you,
Sungwoo.

divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 PID: 67 Comm: kworker/u5:0 Tainted: G        W          6.9.0-rc5+ #20
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Workqueue: hci0 hci_rx_work
RIP: 0010:l2cap_le_flowctl_init+0x19e/0x3f0 net/bluetooth/l2cap_core.c:547
Code: e8 17 17 0c 00 66 41 89 9f 84 00 00 00 bf 01 00 00 00 41 b8 02 00 00 00 4c 89 fe 4c 89 e2 89 d9 e8 27 17 0c 00 44 89 f0 31 d2 <66> f7 f3 89 c3 ff c3 4d 8d b7 88 00 00 00 4c 89 f0 48 c1 e8 03 42
RSP: 0018:ffff88810bc0f858 EFLAGS: 00010246
RAX: 00000000000002a0 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: ffff88810bc0f7c0 RDI: ffffc90002dcb66f
RBP: ffff88810bc0f880 R08: aa69db2dda70ff01 R09: 0000ffaaaaaaaaaa
R10: 0084000000ffaaaa R11: 0000000000000000 R12: ffff88810d65a084
R13: dffffc0000000000 R14: 00000000000002a0 R15: ffff88810d65a000
FS:  0000000000000000(0000) GS:ffff88811ac00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000100 CR3: 0000000103268003 CR4: 0000000000770ef0
PKRU: 55555554
Call Trace:
 <TASK>
 l2cap_le_connect_req net/bluetooth/l2cap_core.c:4902 [inline]
 l2cap_le_sig_cmd net/bluetooth/l2cap_core.c:5420 [inline]
 l2cap_le_sig_channel net/bluetooth/l2cap_core.c:5486 [inline]
 l2cap_recv_frame+0xe59d/0x11710 net/bluetooth/l2cap_core.c:6809
 l2cap_recv_acldata+0x544/0x10a0 net/bluetooth/l2cap_core.c:7506
 hci_acldata_packet net/bluetooth/hci_core.c:3939 [inline]
 hci_rx_work+0x5e5/0xb20 net/bluetooth/hci_core.c:4176
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0x90f/0x1530 kernel/workqueue.c:3335
 worker_thread+0x926/0xe70 kernel/workqueue.c:3416
 kthread+0x2e3/0x380 kernel/kthread.c:388
 ret_from_fork+0x5c/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---

Signed-off-by: Sungwoo Kim <iam@sung-woo.kim>
---
v1 -> v2:
- Reply with an error code if a given MTU is not valid.
- Refuse hcon allocation if MTU is not still valid.

 include/net/bluetooth/hci.h | 6 ++++++
 net/bluetooth/hci_conn.c    | 4 ++++
 net/bluetooth/hci_event.c   | 6 ++++++
 3 files changed, 16 insertions(+)

Comments

bluez.test.bot@gmail.com May 1, 2024, 4:57 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=849562

---Test result---

Test Summary:
CheckPatch                    FAIL      1.30 seconds
GitLint                       FAIL      0.52 seconds
SubjectPrefix                 PASS      0.13 seconds
BuildKernel                   PASS      29.98 seconds
CheckAllWarning               PASS      34.78 seconds
CheckSparse                   WARNING   41.73 seconds
CheckSmatch                   FAIL      36.49 seconds
BuildKernel32                 PASS      29.28 seconds
TestRunnerSetup               PASS      525.06 seconds
TestRunner_l2cap-tester       PASS      23.57 seconds
TestRunner_iso-tester         PASS      31.38 seconds
TestRunner_bnep-tester        PASS      4.79 seconds
TestRunner_mgmt-tester        FAIL      119.48 seconds
TestRunner_rfcomm-tester      PASS      7.26 seconds
TestRunner_sco-tester         PASS      15.00 seconds
TestRunner_ioctl-tester       PASS      7.70 seconds
TestRunner_mesh-tester        FAIL      5.98 seconds
TestRunner_smp-tester         PASS      6.85 seconds
TestRunner_userchan-tester    PASS      4.94 seconds
IncrementalBuild              PASS      28.88 seconds

Details
##############################
Test: CheckPatch - FAIL
Desc: Run checkpatch.pl script
Output:
[v2] Bluetooth: L2CAP: Fix div-by-zero in l2cap_le_flowctl_init()
WARNING: Prefer a maximum 75 chars per line (possible unwrapped commit description?)
#122: 
CPU: 0 PID: 67 Comm: kworker/u5:0 Tainted: G        W          6.9.0-rc5+ #20

total: 0 errors, 1 warnings, 0 checks, 40 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.

/github/workspace/src/src/13650236.patch has style problems, please review.

NOTE: Ignored message types: UNKNOWN_COMMIT_ID

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


##############################
Test: GitLint - FAIL
Desc: Run gitlint
Output:
[v2] Bluetooth: L2CAP: Fix div-by-zero in l2cap_le_flowctl_init()

WARNING: I3 - ignore-body-lines: gitlint will be switching from using Python regex 'match' (match beginning) to 'search' (match anywhere) semantics. Please review your ignore-body-lines.regex option accordingly. To remove this warning, set general.regex-style-search=True. More details: https://jorisroovers.github.io/gitlint/configuration/#regex-style-search
44: B1 Line exceeds max length (199>80): "Code: e8 17 17 0c 00 66 41 89 9f 84 00 00 00 bf 01 00 00 00 41 b8 02 00 00 00 4c 89 fe 4c 89 e2 89 d9 e8 27 17 0c 00 44 89 f0 31 d2 <66> f7 f3 89 c3 ff c3 4d 8d b7 88 00 00 00 4c 89 f0 48 c1 e8 03 42"
##############################
Test: CheckSparse - WARNING
Desc: Run sparse tool with linux kernel
Output:
net/bluetooth/hci_event.c: note: in included file (through include/net/bluetooth/hci_core.h):
##############################
Test: CheckSmatch - FAIL
Desc: Run smatch tool with source
Output:

Segmentation fault (core dumped)
make[4]: *** [scripts/Makefile.build:244: net/bluetooth/hci_core.o] Error 139
make[4]: *** Deleting file 'net/bluetooth/hci_core.o'
make[3]: *** [scripts/Makefile.build:485: net/bluetooth] Error 2
make[2]: *** [scripts/Makefile.build:485: net] Error 2
make[2]: *** Waiting for unfinished jobs....
Segmentation fault (core dumped)
make[4]: *** [scripts/Makefile.build:244: drivers/bluetooth/bcm203x.o] Error 139
make[4]: *** Deleting file 'drivers/bluetooth/bcm203x.o'
make[4]: *** Waiting for unfinished jobs....
Segmentation fault (core dumped)
make[4]: *** [scripts/Makefile.build:244: drivers/bluetooth/bpa10x.o] Error 139
make[4]: *** Deleting file 'drivers/bluetooth/bpa10x.o'
make[3]: *** [scripts/Makefile.build:485: drivers/bluetooth] Error 2
make[2]: *** [scripts/Makefile.build:485: drivers] Error 2
make[1]: *** [/github/workspace/src/src/Makefile:1919: .] Error 2
make: *** [Makefile:240: __sub-make] Error 2
##############################
Test: TestRunner_mgmt-tester - FAIL
Desc: Run mgmt-tester with test-runner
Output:
Total: 492, Passed: 489 (99.4%), Failed: 1, Not Run: 2

Failed Test Cases
LL Privacy - Start Discovery 2 (Disable RL)          Failed       0.163 seconds
##############################
Test: TestRunner_mesh-tester - FAIL
Desc: Run mesh-tester with test-runner
Output:
Total: 10, Passed: 9 (90.0%), Failed: 1, Not Run: 0

Failed Test Cases
Mesh - Send cancel - 2                               Failed       0.099 seconds


---
Regards,
Linux Bluetooth
Luiz Augusto von Dentz May 1, 2024, 1:56 p.m. UTC | #2
Hi Sungwoo,

On Wed, May 1, 2024 at 12:32 AM Sungwoo Kim <iam@sung-woo.kim> wrote:
>
> Hi Luiz, could you review this patch?
>
> This patch prevents a div-by-zero error and potential int overflow by
> adding a range check for MTU in hci_cc_le_read_buffer_size() and
> hci_cc_le_read_buffer_size_v2().
> Also, hci_connect_le() will refuse to allocate hcon if the MTU is not in
> the valid range.
>
> Bug description:
>
> l2cap_le_flowctl_init() can cause both div-by-zero and an integer overflow.
>
> l2cap_le_flowctl_init()
>   chan->mps = min_t(u16, chan->imtu, chan->conn->mtu - L2CAP_HDR_SIZE);
>   chan->rx_credits = (chan->imtu / chan->mps) + 1;  <- div-by-zero
>
> Here, chan->conn->mtu could be less than or equal to L2CAP_HDR_SIZE (4).
> If mtu is 4, it causes div-by-zero. If mtu is less than 4, it causes an
> integer overflow.
>
> How mtu could have such low value:
>
> hci_cc_le_read_buffer_size()
>   hdev->le_mtu = __le16_to_cpu(rp->le_mtu);
>
> l2cap_conn_add()
>   conn->mtu = hcon->hdev->le_mtu;
>
> As shown, mtu is an input from an HCI device. So, any HCI device can
> set mtu value to any value, such as lower than 4.
> According to the spec v5.4 7.8.2 LE Read Buffer Size command, the value
> should be fall in [0x001b, 0xffff].
>
> Thank you,
> Sungwoo.
>
> divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI
> CPU: 0 PID: 67 Comm: kworker/u5:0 Tainted: G        W          6.9.0-rc5+ #20
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
> Workqueue: hci0 hci_rx_work
> RIP: 0010:l2cap_le_flowctl_init+0x19e/0x3f0 net/bluetooth/l2cap_core.c:547
> Code: e8 17 17 0c 00 66 41 89 9f 84 00 00 00 bf 01 00 00 00 41 b8 02 00 00 00 4c 89 fe 4c 89 e2 89 d9 e8 27 17 0c 00 44 89 f0 31 d2 <66> f7 f3 89 c3 ff c3 4d 8d b7 88 00 00 00 4c 89 f0 48 c1 e8 03 42
> RSP: 0018:ffff88810bc0f858 EFLAGS: 00010246
> RAX: 00000000000002a0 RBX: 0000000000000000 RCX: dffffc0000000000
> RDX: 0000000000000000 RSI: ffff88810bc0f7c0 RDI: ffffc90002dcb66f
> RBP: ffff88810bc0f880 R08: aa69db2dda70ff01 R09: 0000ffaaaaaaaaaa
> R10: 0084000000ffaaaa R11: 0000000000000000 R12: ffff88810d65a084
> R13: dffffc0000000000 R14: 00000000000002a0 R15: ffff88810d65a000
> FS:  0000000000000000(0000) GS:ffff88811ac00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000020000100 CR3: 0000000103268003 CR4: 0000000000770ef0
> PKRU: 55555554
> Call Trace:
>  <TASK>
>  l2cap_le_connect_req net/bluetooth/l2cap_core.c:4902 [inline]
>  l2cap_le_sig_cmd net/bluetooth/l2cap_core.c:5420 [inline]
>  l2cap_le_sig_channel net/bluetooth/l2cap_core.c:5486 [inline]
>  l2cap_recv_frame+0xe59d/0x11710 net/bluetooth/l2cap_core.c:6809
>  l2cap_recv_acldata+0x544/0x10a0 net/bluetooth/l2cap_core.c:7506
>  hci_acldata_packet net/bluetooth/hci_core.c:3939 [inline]
>  hci_rx_work+0x5e5/0xb20 net/bluetooth/hci_core.c:4176
>  process_one_work kernel/workqueue.c:3254 [inline]
>  process_scheduled_works+0x90f/0x1530 kernel/workqueue.c:3335
>  worker_thread+0x926/0xe70 kernel/workqueue.c:3416
>  kthread+0x2e3/0x380 kernel/kthread.c:388
>  ret_from_fork+0x5c/0x90 arch/x86/kernel/process.c:147
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
>  </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
>
> Signed-off-by: Sungwoo Kim <iam@sung-woo.kim>
> ---
> v1 -> v2:
> - Reply with an error code if a given MTU is not valid.
> - Refuse hcon allocation if MTU is not still valid.
>
>  include/net/bluetooth/hci.h | 6 ++++++
>  net/bluetooth/hci_conn.c    | 4 ++++
>  net/bluetooth/hci_event.c   | 6 ++++++
>  3 files changed, 16 insertions(+)
>
> diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
> index 5c12761cb..a7bc07e9c 100644
> --- a/include/net/bluetooth/hci.h
> +++ b/include/net/bluetooth/hci.h
> @@ -1666,6 +1666,12 @@ struct hci_cp_le_set_event_mask {
>         __u8     mask[8];
>  } __packed;
>
> +/* BLUETOOTH CORE SPECIFICATION Version 5.4 | Vol 4, Part E
> + * 7.8.2 LE Read Buffer Size command
> + */
> +#define HCI_MIN_LE_MTU 0x001b
> +#define HCI_MAX_LE_MTU 0xFFFF

Don't think we really need the MAX value here since it is that same as
the maximum field can assume so doing x > MAX is sort of useless as it
loops around if that happens.

>  #define HCI_OP_LE_READ_BUFFER_SIZE     0x2002
>  struct hci_rp_le_read_buffer_size {
>         __u8     status;
> diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
> index 05346250f..0b86a7452 100644
> --- a/net/bluetooth/hci_conn.c
> +++ b/net/bluetooth/hci_conn.c
> @@ -1277,6 +1277,10 @@ struct hci_conn *hci_connect_le(struct hci_dev *hdev, bdaddr_t *dst,
>                 return ERR_PTR(-EOPNOTSUPP);
>         }
>
> +       /* Check the mtu is valid */
> +       if (hdev->le_mtu < HCI_MIN_LE_MTU || HCI_MAX_LE_MTU < hdev->le_mtu)
> +               return ERR_PTR(-ECONNREFUSED);
> +

That probably needs to be done on hci_conn_add if we want to capture
both incoming and outgoing.

>         /* Since the controller supports only one LE connection attempt at a
>          * time, we return -EBUSY if there is any connection attempt running.
>          */
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index 4a27e4a17..a8563cbe2 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -1263,6 +1263,9 @@ static u8 hci_cc_le_read_buffer_size(struct hci_dev *hdev, void *data,
>
>         BT_DBG("%s le mtu %d:%d", hdev->name, hdev->le_mtu, hdev->le_pkts);
>
> +       if (hdev->le_mtu < HCI_MIN_LE_MTU || HCI_MAX_LE_MTU < hdev->le_mtu)
> +               return HCI_ERROR_INVALID_PARAMETERS;

Value 0x00 means 'No dedicated LE Buffer exists. Use the
HCI_Read_Buffer_Size command.' so it is not invalid to return it.

>         return rp->status;
>  }
>
> @@ -3821,6 +3824,9 @@ static u8 hci_cc_le_read_buffer_size_v2(struct hci_dev *hdev, void *data,
>         BT_DBG("%s acl mtu %d:%d iso mtu %d:%d", hdev->name, hdev->acl_mtu,
>                hdev->acl_pkts, hdev->iso_mtu, hdev->iso_pkts);
>
> +       if (hdev->le_mtu < HCI_MIN_LE_MTU || HCI_MAX_LE_MTU < hdev->le_mtu)
> +               return HCI_ERROR_INVALID_PARAMETERS;

Ditto, this should really be:

if (hdev->le_mtu && hdev->le_mtu < HCI_MIN_LE_MTU)

>         return rp->status;
>  }
>
> --
> 2.34.1
>
diff mbox series

Patch

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 5c12761cb..a7bc07e9c 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -1666,6 +1666,12 @@  struct hci_cp_le_set_event_mask {
 	__u8     mask[8];
 } __packed;
 
+/* BLUETOOTH CORE SPECIFICATION Version 5.4 | Vol 4, Part E
+ * 7.8.2 LE Read Buffer Size command
+ */
+#define HCI_MIN_LE_MTU 0x001b
+#define HCI_MAX_LE_MTU 0xFFFF
+
 #define HCI_OP_LE_READ_BUFFER_SIZE	0x2002
 struct hci_rp_le_read_buffer_size {
 	__u8     status;
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 05346250f..0b86a7452 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -1277,6 +1277,10 @@  struct hci_conn *hci_connect_le(struct hci_dev *hdev, bdaddr_t *dst,
 		return ERR_PTR(-EOPNOTSUPP);
 	}
 
+	/* Check the mtu is valid */
+	if (hdev->le_mtu < HCI_MIN_LE_MTU || HCI_MAX_LE_MTU < hdev->le_mtu)
+		return ERR_PTR(-ECONNREFUSED);
+
 	/* Since the controller supports only one LE connection attempt at a
 	 * time, we return -EBUSY if there is any connection attempt running.
 	 */
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 4a27e4a17..a8563cbe2 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -1263,6 +1263,9 @@  static u8 hci_cc_le_read_buffer_size(struct hci_dev *hdev, void *data,
 
 	BT_DBG("%s le mtu %d:%d", hdev->name, hdev->le_mtu, hdev->le_pkts);
 
+	if (hdev->le_mtu < HCI_MIN_LE_MTU || HCI_MAX_LE_MTU < hdev->le_mtu)
+		return HCI_ERROR_INVALID_PARAMETERS;
+
 	return rp->status;
 }
 
@@ -3821,6 +3824,9 @@  static u8 hci_cc_le_read_buffer_size_v2(struct hci_dev *hdev, void *data,
 	BT_DBG("%s acl mtu %d:%d iso mtu %d:%d", hdev->name, hdev->acl_mtu,
 	       hdev->acl_pkts, hdev->iso_mtu, hdev->iso_pkts);
 
+	if (hdev->le_mtu < HCI_MIN_LE_MTU || HCI_MAX_LE_MTU < hdev->le_mtu)
+		return HCI_ERROR_INVALID_PARAMETERS;
+
 	return rp->status;
 }