diff mbox series

[v4] Bluetooth: L2CAP: Fix div-by-zero in l2cap_le_flowctl_init()

Message ID 20240504192329.351126-1-iam@sung-woo.kim
State Superseded
Headers show
Series [v4] Bluetooth: L2CAP: Fix div-by-zero in l2cap_le_flowctl_init() | expand

Commit Message

Sungwoo Kim May 4, 2024, 7:23 p.m. UTC 
l2cap_le_flowctl_init() can cause both div-by-zero and an integer
overflow since hdev->le_mtu may not fall in the valid range.

Move MTU from hci_dev to hci_conn to validate MTU and stop the connection
process earlier if MTU is invalid.
Also, add a missing validation in read_buffer_size() and make it return
an error value if the validation fails.
Now hci_conn_add() returns ERR_PTR() as it can fail due to the both a
kzalloc failure and invalid MTU value.

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 ]---

Fixes: 6ed58ec520ad ("Bluetooth: Use LE buffers for LE traffic")
Suggested-by: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
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.
v2 -> v3:
- Move mtu to hcon.
- Make SCO, ISO, and L2CAP use hcon->mtu.
v3 -> v4:
- Generate a new diff aligned to bluetooth-next

 include/net/bluetooth/hci.h      |  9 ++++
 include/net/bluetooth/hci_core.h |  1 +
 net/bluetooth/hci_conn.c         | 75 ++++++++++++++++++++++----------
 net/bluetooth/hci_event.c        | 31 ++++++++-----
 net/bluetooth/iso.c              |  2 +-
 net/bluetooth/l2cap_core.c       | 17 ++------
 net/bluetooth/sco.c              |  6 +--
 7 files changed, 88 insertions(+), 53 deletions(-)

Comments

bluez.test.bot@gmail.com May 4, 2024, 7:55 p.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=850490

---Test result---

Test Summary:
CheckPatch                    FAIL      2.01 seconds
GitLint                       FAIL      0.50 seconds
SubjectPrefix                 PASS      0.10 seconds
BuildKernel                   PASS      29.25 seconds
CheckAllWarning               PASS      31.80 seconds
CheckSparse                   WARNING   37.26 seconds
CheckSmatch                   FAIL      35.23 seconds
BuildKernel32                 PASS      28.22 seconds
TestRunnerSetup               PASS      511.11 seconds
TestRunner_l2cap-tester       PASS      20.21 seconds
TestRunner_iso-tester         PASS      28.19 seconds
TestRunner_bnep-tester        PASS      4.66 seconds
TestRunner_mgmt-tester        FAIL      108.29 seconds
TestRunner_rfcomm-tester      PASS      7.13 seconds
TestRunner_sco-tester         PASS      14.83 seconds
TestRunner_ioctl-tester       PASS      7.42 seconds
TestRunner_mesh-tester        PASS      5.68 seconds
TestRunner_smp-tester         PASS      6.68 seconds
TestRunner_userchan-tester    PASS      4.79 seconds
IncrementalBuild              PASS      27.22 seconds

Details
##############################
Test: CheckPatch - FAIL
Desc: Run checkpatch.pl script
Output:
[v4] Bluetooth: L2CAP: Fix div-by-zero in l2cap_le_flowctl_init()
WARNING: Prefer a maximum 75 chars per line (possible unwrapped commit description?)
#96: 
CPU: 0 PID: 67 Comm: kworker/u5:0 Tainted: G        W          6.9.0-rc5+ #20

total: 0 errors, 1 warnings, 0 checks, 340 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/13654104.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:
[v4] 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
18: 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):net/bluetooth/sco.c: note: in included file:./include/net/bluetooth/hci_core.h:150:35: warning: array of flexible structures
##############################
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 - Add Device 5 (2 Devices to RL)          Failed       0.154 seconds


---
Regards,
Linux Bluetooth
patchwork-bot+bluetooth@kernel.org May 6, 2024, 5 p.m. UTC | #2 
Hello:

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

On Sat,  4 May 2024 15:23:29 -0400 you wrote:
> l2cap_le_flowctl_init() can cause both div-by-zero and an integer
> overflow since hdev->le_mtu may not fall in the valid range.
> 
> Move MTU from hci_dev to hci_conn to validate MTU and stop the connection
> process earlier if MTU is invalid.
> Also, add a missing validation in read_buffer_size() and make it return
> an error value if the validation fails.
> Now hci_conn_add() returns ERR_PTR() as it can fail due to the both a
> kzalloc failure and invalid MTU value.
> 
> [...]

Here is the summary with links:
  - [v4] Bluetooth: L2CAP: Fix div-by-zero in l2cap_le_flowctl_init()
    https://git.kernel.org/bluetooth/bluetooth-next/c/93e31170f4d0

You are awesome, thank you!
diff mbox series

Patch

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 21ebd70f3..de530262d 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -1665,6 +1665,15 @@  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
+ * MAX_LE_MTU is 0xffff.
+ * 0 is also valid. It means that no dedicated LE Buffer exists.
+ * It should use the HCI_Read_Buffer_Size command and mtu is shared
+ * between BR/EDR and LE.
+ */
+#define HCI_MIN_LE_MTU 0x001b
+
 #define HCI_OP_LE_READ_BUFFER_SIZE	0x2002
 struct hci_rp_le_read_buffer_size {
 	__u8     status;
diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 94bae125a..1f72962e4 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -712,6 +712,7 @@  struct hci_conn {
 	__u16		handle;
 	__u16		sync_handle;
 	__u16		state;
+	__u16		mtu;
 	__u8		mode;
 	__u8		type;
 	__u8		role;
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 6e60e8287..171a667bc 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -905,11 +905,37 @@  struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst,
 {
 	struct hci_conn *conn;
 
+	switch (type) {
+	case ACL_LINK:
+		if (!hdev->acl_mtu)
+			return ERR_PTR(-ECONNREFUSED);
+		break;
+	case ISO_LINK:
+		if (hdev->iso_mtu)
+			/* Dedicated ISO Buffer exists */
+			break;
+		fallthrough;
+	case LE_LINK:
+		if (hdev->le_mtu && hdev->le_mtu < HCI_MIN_LE_MTU)
+			return ERR_PTR(-ECONNREFUSED);
+		if (!hdev->le_mtu && hdev->acl_mtu < HCI_MIN_LE_MTU)
+			return ERR_PTR(-ECONNREFUSED);
+		break;
+	case SCO_LINK:
+	case ESCO_LINK:
+		if (!hdev->sco_pkts)
+			/* Controller does not support SCO or eSCO over HCI */
+			return ERR_PTR(-ECONNREFUSED);
+		break;
+	default:
+		return ERR_PTR(-ECONNREFUSED);
+	}
+
 	bt_dev_dbg(hdev, "dst %pMR handle 0x%4.4x", dst, handle);
 
 	conn = kzalloc(sizeof(*conn), GFP_KERNEL);
 	if (!conn)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	bacpy(&conn->dst, dst);
 	bacpy(&conn->src, &hdev->bdaddr);
@@ -940,10 +966,12 @@  struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst,
 	switch (type) {
 	case ACL_LINK:
 		conn->pkt_type = hdev->pkt_type & ACL_PTYPE_MASK;
+		conn->mtu = hdev->acl_mtu;
 		break;
 	case LE_LINK:
 		/* conn->src should reflect the local identity address */
 		hci_copy_identity_address(hdev, &conn->src, &conn->src_type);
+		conn->mtu = hdev->le_mtu ? hdev->le_mtu : hdev->acl_mtu;
 		break;
 	case ISO_LINK:
 		/* conn->src should reflect the local identity address */
@@ -955,6 +983,8 @@  struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst,
 		else if (conn->role == HCI_ROLE_MASTER)
 			conn->cleanup = cis_cleanup;
 
+		conn->mtu = hdev->iso_mtu ? hdev->iso_mtu :
+			    hdev->le_mtu ? hdev->le_mtu : hdev->acl_mtu;
 		break;
 	case SCO_LINK:
 		if (lmp_esco_capable(hdev))
@@ -962,9 +992,12 @@  struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst,
 					(hdev->esco_type & EDR_ESCO_MASK);
 		else
 			conn->pkt_type = hdev->pkt_type & SCO_PTYPE_MASK;
+
+		conn->mtu = hdev->sco_mtu;
 		break;
 	case ESCO_LINK:
 		conn->pkt_type = hdev->esco_type & ~EDR_ESCO_MASK;
+		conn->mtu = hdev->sco_mtu;
 		break;
 	}
 
@@ -1008,7 +1041,7 @@  struct hci_conn *hci_conn_add_unset(struct hci_dev *hdev, int type,
 
 	handle = hci_conn_hash_alloc_unset(hdev);
 	if (unlikely(handle < 0))
-		return NULL;
+		return ERR_PTR(-ECONNREFUSED);
 
 	return hci_conn_add(hdev, type, dst, role, handle);
 }
@@ -1315,8 +1348,8 @@  struct hci_conn *hci_connect_le(struct hci_dev *hdev, bdaddr_t *dst,
 		bacpy(&conn->dst, dst);
 	} else {
 		conn = hci_conn_add_unset(hdev, LE_LINK, dst, role);
-		if (!conn)
-			return ERR_PTR(-ENOMEM);
+		if (IS_ERR(conn))
+			return conn;
 		hci_conn_hold(conn);
 		conn->pending_sec_level = sec_level;
 	}
@@ -1492,8 +1525,8 @@  static struct hci_conn *hci_add_bis(struct hci_dev *hdev, bdaddr_t *dst,
 		return ERR_PTR(-EADDRINUSE);
 
 	conn = hci_conn_add_unset(hdev, ISO_LINK, dst, HCI_ROLE_MASTER);
-	if (!conn)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(conn))
+		return conn;
 
 	conn->state = BT_CONNECT;
 
@@ -1536,8 +1569,8 @@  struct hci_conn *hci_connect_le_scan(struct hci_dev *hdev, bdaddr_t *dst,
 	BT_DBG("requesting refresh of dst_addr");
 
 	conn = hci_conn_add_unset(hdev, LE_LINK, dst, HCI_ROLE_MASTER);
-	if (!conn)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(conn))
+		return conn;
 
 	if (hci_explicit_conn_params_set(hdev, dst, dst_type) < 0) {
 		hci_conn_del(conn);
@@ -1584,8 +1617,8 @@  struct hci_conn *hci_connect_acl(struct hci_dev *hdev, bdaddr_t *dst,
 	acl = hci_conn_hash_lookup_ba(hdev, ACL_LINK, dst);
 	if (!acl) {
 		acl = hci_conn_add_unset(hdev, ACL_LINK, dst, HCI_ROLE_MASTER);
-		if (!acl)
-			return ERR_PTR(-ENOMEM);
+		if (IS_ERR(acl))
+			return acl;
 	}
 
 	hci_conn_hold(acl);
@@ -1653,9 +1686,9 @@  struct hci_conn *hci_connect_sco(struct hci_dev *hdev, int type, bdaddr_t *dst,
 	sco = hci_conn_hash_lookup_ba(hdev, type, dst);
 	if (!sco) {
 		sco = hci_conn_add_unset(hdev, type, dst, HCI_ROLE_MASTER);
-		if (!sco) {
+		if (IS_ERR(sco)) {
 			hci_conn_drop(acl);
-			return ERR_PTR(-ENOMEM);
+			return sco;
 		}
 	}
 
@@ -1844,8 +1877,8 @@  struct hci_conn *hci_bind_cis(struct hci_dev *hdev, bdaddr_t *dst,
 				       qos->ucast.cis);
 	if (!cis) {
 		cis = hci_conn_add_unset(hdev, ISO_LINK, dst, HCI_ROLE_MASTER);
-		if (!cis)
-			return ERR_PTR(-ENOMEM);
+		if (IS_ERR(cis))
+			return cis;
 		cis->cleanup = cis_cleanup;
 		cis->dst_type = dst_type;
 		cis->iso_qos.ucast.cig = BT_ISO_QOS_CIG_UNSET;
@@ -1980,14 +2013,8 @@  static void hci_iso_qos_setup(struct hci_dev *hdev, struct hci_conn *conn,
 			      struct bt_iso_io_qos *qos, __u8 phy)
 {
 	/* Only set MTU if PHY is enabled */
-	if (!qos->sdu && qos->phy) {
-		if (hdev->iso_mtu > 0)
-			qos->sdu = hdev->iso_mtu;
-		else if (hdev->le_mtu > 0)
-			qos->sdu = hdev->le_mtu;
-		else
-			qos->sdu = hdev->acl_mtu;
-	}
+	if (!qos->sdu && qos->phy)
+		qos->sdu = conn->mtu;
 
 	/* Use the same PHY as ACL if set to any */
 	if (qos->phy == BT_ISO_PHY_ANY)
@@ -2068,8 +2095,8 @@  struct hci_conn *hci_pa_create_sync(struct hci_dev *hdev, bdaddr_t *dst,
 		return ERR_PTR(-EBUSY);
 
 	conn = hci_conn_add_unset(hdev, ISO_LINK, dst, HCI_ROLE_SLAVE);
-	if (!conn)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(conn))
+		return conn;
 
 	conn->iso_qos = *qos;
 	conn->state = BT_LISTEN;
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 8c673814a..1edbe4de1 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -954,6 +954,9 @@  static u8 hci_cc_read_buffer_size(struct hci_dev *hdev, void *data,
 	BT_DBG("%s acl mtu %d:%d sco mtu %d:%d", hdev->name, hdev->acl_mtu,
 	       hdev->acl_pkts, hdev->sco_mtu, hdev->sco_pkts);
 
+	if (!hdev->acl_mtu || !hdev->acl_pkts)
+		return HCI_ERROR_INVALID_PARAMETERS;
+
 	return rp->status;
 }
 
@@ -1263,6 +1266,9 @@  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 && hdev->le_mtu < HCI_MIN_LE_MTU)
+		return HCI_ERROR_INVALID_PARAMETERS;
+
 	return rp->status;
 }
 
@@ -2341,8 +2347,8 @@  static void hci_cs_create_conn(struct hci_dev *hdev, __u8 status)
 		if (!conn) {
 			conn = hci_conn_add_unset(hdev, ACL_LINK, &cp->bdaddr,
 						  HCI_ROLE_MASTER);
-			if (!conn)
-				bt_dev_err(hdev, "no memory for new connection");
+			if (IS_ERR(conn))
+				bt_dev_err(hdev, "connection err: %ld", PTR_ERR(conn));
 		}
 	}
 
@@ -3153,8 +3159,8 @@  static void hci_conn_complete_evt(struct hci_dev *hdev, void *data,
 						      BDADDR_BREDR)) {
 			conn = hci_conn_add_unset(hdev, ev->link_type,
 						  &ev->bdaddr, HCI_ROLE_SLAVE);
-			if (!conn) {
-				bt_dev_err(hdev, "no memory for new conn");
+			if (IS_ERR(conn)) {
+				bt_dev_err(hdev, "connection err: %ld", PTR_ERR(conn));
 				goto unlock;
 			}
 		} else {
@@ -3342,8 +3348,8 @@  static void hci_conn_request_evt(struct hci_dev *hdev, void *data,
 	if (!conn) {
 		conn = hci_conn_add_unset(hdev, ev->link_type, &ev->bdaddr,
 					  HCI_ROLE_SLAVE);
-		if (!conn) {
-			bt_dev_err(hdev, "no memory for new connection");
+		if (IS_ERR(conn)) {
+			bt_dev_err(hdev, "connection err: %ld", PTR_ERR(conn));
 			goto unlock;
 		}
 	}
@@ -3820,6 +3826,9 @@  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 && hdev->le_mtu < HCI_MIN_LE_MTU)
+		return HCI_ERROR_INVALID_PARAMETERS;
+
 	return rp->status;
 }
 
@@ -5777,8 +5786,8 @@  static void le_conn_complete_evt(struct hci_dev *hdev, u8 status,
 			goto unlock;
 
 		conn = hci_conn_add_unset(hdev, LE_LINK, bdaddr, role);
-		if (!conn) {
-			bt_dev_err(hdev, "no memory for new connection");
+		if (IS_ERR(conn)) {
+			bt_dev_err(hdev, "connection err: %ld", PTR_ERR(conn));
 			goto unlock;
 		}
 
@@ -6506,7 +6515,7 @@  static void hci_le_pa_sync_estabilished_evt(struct hci_dev *hdev, void *data,
 	pa_sync = hci_conn_add_unset(hdev, ISO_LINK, BDADDR_ANY,
 				     HCI_ROLE_SLAVE);
 
-	if (!pa_sync)
+	if (IS_ERR(pa_sync))
 		goto unlock;
 
 	pa_sync->sync_handle = le16_to_cpu(ev->handle);
@@ -6930,7 +6939,7 @@  static void hci_le_cis_req_evt(struct hci_dev *hdev, void *data,
 	if (!cis) {
 		cis = hci_conn_add(hdev, ISO_LINK, &acl->dst, HCI_ROLE_SLAVE,
 				   cis_handle);
-		if (!cis) {
+		if (IS_ERR(cis)) {
 			hci_le_reject_cis(hdev, ev->cis_handle);
 			goto unlock;
 		}
@@ -7039,7 +7048,7 @@  static void hci_le_big_sync_established_evt(struct hci_dev *hdev, void *data,
 		if (!bis) {
 			bis = hci_conn_add(hdev, ISO_LINK, BDADDR_ANY,
 					   HCI_ROLE_SLAVE, handle);
-			if (!bis)
+			if (IS_ERR(bis))
 				continue;
 		}
 
diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index 8642ffc32..c907a1a8f 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -1270,7 +1270,7 @@  static int iso_sock_sendmsg(struct socket *sock, struct msghdr *msg,
 		return -ENOTCONN;
 	}
 
-	mtu = iso_pi(sk)->conn->hcon->hdev->iso_mtu;
+	mtu = iso_pi(sk)->conn->hcon->mtu;
 
 	release_sock(sk);
 
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 2b807b744..43bd61cee 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -6274,7 +6274,7 @@  static int l2cap_finish_move(struct l2cap_chan *chan)
 	BT_DBG("chan %p", chan);
 
 	chan->rx_state = L2CAP_RX_STATE_RECV;
-	chan->conn->mtu = chan->conn->hcon->hdev->acl_mtu;
+	chan->conn->mtu = chan->conn->hcon->mtu;
 
 	return l2cap_resegment(chan);
 }
@@ -6341,7 +6341,7 @@  static int l2cap_rx_state_wait_f(struct l2cap_chan *chan,
 	 */
 	chan->next_tx_seq = control->reqseq;
 	chan->unacked_frames = 0;
-	chan->conn->mtu = chan->conn->hcon->hdev->acl_mtu;
+	chan->conn->mtu = chan->conn->hcon->mtu;
 
 	err = l2cap_resegment(chan);
 
@@ -6899,18 +6899,7 @@  static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon)
 
 	BT_DBG("hcon %p conn %p hchan %p", hcon, conn, hchan);
 
-	switch (hcon->type) {
-	case LE_LINK:
-		if (hcon->hdev->le_mtu) {
-			conn->mtu = hcon->hdev->le_mtu;
-			break;
-		}
-		fallthrough;
-	default:
-		conn->mtu = hcon->hdev->acl_mtu;
-		break;
-	}
-
+	conn->mtu = hcon->mtu;
 	conn->feat_mask = 0;
 
 	conn->local_fixed_chan = L2CAP_FC_SIG_BREDR | L2CAP_FC_CONNLESS;
diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 69656a48c..75b975e20 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -126,7 +126,6 @@  static void sco_sock_clear_timer(struct sock *sk)
 /* ---- SCO connections ---- */
 static struct sco_conn *sco_conn_add(struct hci_conn *hcon)
 {
-	struct hci_dev *hdev = hcon->hdev;
 	struct sco_conn *conn = hcon->sco_data;
 
 	if (conn) {
@@ -144,9 +143,10 @@  static struct sco_conn *sco_conn_add(struct hci_conn *hcon)
 
 	hcon->sco_data = conn;
 	conn->hcon = hcon;
+	conn->mtu = hcon->mtu;
 
-	if (hdev->sco_mtu > 0)
-		conn->mtu = hdev->sco_mtu;
+	if (hcon->mtu > 0)
+		conn->mtu = hcon->mtu;
 	else
 		conn->mtu = 60;