kernel/linux.git/include/net/bluetooth/l2cap.h, branch v6.1.168

Bluetooth: L2CAP: Fix invalid response to L2CAP_ECRED_RECONF_REQ

2026-03-04T12:20:40+00:00

[ Upstream commit 7accb1c4321acb617faf934af59d928b0b047e2b ] This fixes responding with an invalid result caused by checking the wrong size of CID which should have been (cmd_len - sizeof(*req)) and on top of it the wrong result was use L2CAP_CR_LE_INVALID_PARAMS which is invalid/reserved for reconf when running test like L2CAP/ECFC/BI-03-C: > ACL Data RX: Handle 64 flags 0x02 dlen 14 LE L2CAP: Enhanced Credit Reconfigure Request (0x19) ident 2 len 6 MTU: 64 MPS: 64 Source CID: 64 < ACL Data TX: Handle 64 flags 0x00 dlen 10 LE L2CAP: Enhanced Credit Reconfigure Respond (0x1a) ident 2 len 2 ! Result: Reserved (0x000c) Result: Reconfiguration failed - one or more Destination CIDs invalid (0x0003) Fiix L2CAP/ECFC/BI-04-C which expects L2CAP_RECONF_INVALID_MPS (0x0002) when more than one channel gets its MPS reduced: > ACL Data RX: Handle 64 flags 0x02 dlen 16 LE L2CAP: Enhanced Credit Reconfigure Request (0x19) ident 2 len 8 MTU: 264 MPS: 99 Source CID: 64 ! Source CID: 65 < ACL Data TX: Handle 64 flags 0x00 dlen 10 LE L2CAP: Enhanced Credit Reconfigure Respond (0x1a) ident 2 len 2 ! Result: Reconfiguration successful (0x0000) Result: Reconfiguration failed - reduction in size of MPS not allowed for more than one channel at a time (0x0002) Fix L2CAP/ECFC/BI-05-C when SCID is invalid (85 unconnected): > ACL Data RX: Handle 64 flags 0x02 dlen 14 LE L2CAP: Enhanced Credit Reconfigure Request (0x19) ident 2 len 6 MTU: 65 MPS: 64 ! Source CID: 85 < ACL Data TX: Handle 64 flags 0x00 dlen 10 LE L2CAP: Enhanced Credit Reconfigure Respond (0x1a) ident 2 len 2 ! Result: Reconfiguration successful (0x0000) Result: Reconfiguration failed - one or more Destination CIDs invalid (0x0003) Fix L2CAP/ECFC/BI-06-C when MPS < L2CAP_ECRED_MIN_MPS (64): > ACL Data RX: Handle 64 flags 0x02 dlen 14 LE L2CAP: Enhanced Credit Reconfigure Request (0x19) ident 2 len 6 MTU: 672 ! MPS: 63 Source CID: 64 < ACL Data TX: Handle 64 flags 0x00 dlen 10 LE L2CAP: Enhanced Credit Reconfigure Respond (0x1a) ident 2 len 2 ! Result: Reconfiguration failed - reduction in size of MPS not allowed for more than one channel at a time (0x0002) Result: Reconfiguration failed - other unacceptable parameters (0x0004) Fix L2CAP/ECFC/BI-07-C when MPS reduced for more than one channel: > ACL Data RX: Handle 64 flags 0x02 dlen 16 LE L2CAP: Enhanced Credit Reconfigure Request (0x19) ident 3 len 8 MTU: 84 ! MPS: 71 Source CID: 64 ! Source CID: 65 < ACL Data TX: Handle 64 flags 0x00 dlen 10 LE L2CAP: Enhanced Credit Reconfigure Respond (0x1a) ident 2 len 2 ! Result: Reconfiguration successful (0x0000) Result: Reconfiguration failed - reduction in size of MPS not allowed for more than one channel at a time (0x0002) Link: https://github.com/bluez/bluez/issues/1865 Fixes: 15f02b910562 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode") Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin

Bluetooth: compute LE flow credits based on recvbuf space

2024-06-12T09:03:20+00:00

[ Upstream commit ce60b9231b66710b6ee24042ded26efee120ecfc ] Previously LE flow credits were returned to the sender even if the socket's receive buffer was full. This meant that no back-pressure was applied to the sender, thus it continued to send data, resulting in data loss without any error being reported. Furthermore, the amount of credits was essentially fixed to a small amount, leading to reduced performance. This is fixed by computing the number of returned LE flow credits based on the estimated available space in the receive buffer of an L2CAP socket. Consequently, if the receive buffer is full, no credits are returned until the buffer is read and thus cleared by user-space. Since the computation of available receive buffer space can only be performed approximately (due to sk_buff overhead) and the receive buffer size may be changed by user-space after flow credits have been sent, superfluous received data is temporary stored within l2cap_pinfo. This is necessary because Bluetooth LE provides no retransmission mechanism once the data has been acked by the physical layer. If receive buffer space estimation is not possible at the moment, we fall back to providing credits for one full packet as before. This is currently the case during connection setup, when MPS is not yet available. Fixes: b1c325c23d75 ("Bluetooth: Implement returning of LE L2CAP credits") Signed-off-by: Sebastian Urban Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin

Bluetooth: L2CAP: Fix use-after-free caused by l2cap_chan_put

2022-07-26T20:35:24+00:00

This fixes the following trace which is caused by hci_rx_work starting up *after* the final channel reference has been put() during sock_close() but *before* the references to the channel have been destroyed, so instead the code now rely on kref_get_unless_zero/l2cap_chan_hold_unless_zero to prevent referencing a channel that is about to be destroyed. refcount_t: increment on 0; use-after-free. BUG: KASAN: use-after-free in refcount_dec_and_test+0x20/0xd0 Read of size 4 at addr ffffffc114f5bf18 by task kworker/u17:14/705 CPU: 4 PID: 705 Comm: kworker/u17:14 Tainted: G S W 4.14.234-00003-g1fb6d0bd49a4-dirty #28 Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150 Google Inc. MSM sm8150 Flame DVT (DT) Workqueue: hci0 hci_rx_work Call trace: dump_backtrace+0x0/0x378 show_stack+0x20/0x2c dump_stack+0x124/0x148 print_address_description+0x80/0x2e8 __kasan_report+0x168/0x188 kasan_report+0x10/0x18 __asan_load4+0x84/0x8c refcount_dec_and_test+0x20/0xd0 l2cap_chan_put+0x48/0x12c l2cap_recv_frame+0x4770/0x6550 l2cap_recv_acldata+0x44c/0x7a4 hci_acldata_packet+0x100/0x188 hci_rx_work+0x178/0x23c process_one_work+0x35c/0x95c worker_thread+0x4cc/0x960 kthread+0x1a8/0x1c4 ret_from_fork+0x10/0x18 Cc: stable@kernel.org Reported-by: Lee Jones Signed-off-by: Luiz Augusto von Dentz Tested-by: Lee Jones Signed-off-by: Luiz Augusto von Dentz

Bluetooth: L2CAP: Fix not checking for maximum number of DCID

2021-03-15T20:08:33+00:00

When receiving L2CAP_CREDIT_BASED_CONNECTION_REQ the remote may request more channels than allowed by the spec (10 octecs = 5 CIDs) so this checks if the number of channels is bigger than the maximum allowed and respond with an error. Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Marcel Holtmann

Bluetooth: L2CAP: Fix handling fragmented length

2021-01-25T18:26:33+00:00

Bluetooth Core Specification v5.2, Vol. 3, Part A, section 1.4, table 1.1: 'Start Fragments always either begin with the first octet of the Basic L2CAP header of a PDU or they have a length of zero (see [Vol 2] Part B, Section 6.6.2).' Apparently this was changed by the following errata: https://www.bluetooth.org/tse/errata_view.cfm?errata_id=10216 Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Marcel Holtmann

Bluetooth: L2CAP: Fix calling sk_filter on non-socket based channel

2020-09-25T18:21:55+00:00

Only sockets will have the chan->data set to an actual sk, channels like A2MP would have its own data which would likely cause a crash when calling sk_filter, in order to fix this a new callback has been introduced so channels can implement their own filtering if necessary. Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Marcel Holtmann

Bluetooth: L2CAP: Replace zero-length array with flexible-array

2020-05-18T07:57:41+00:00

The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva Signed-off-by: Marcel Holtmann

Bluetooth: L2CAP: Use DEFER_SETUP to group ECRED connections

2020-03-25T21:16:08+00:00

This uses the DEFER_SETUP flag to group channels with L2CAP_CREDIT_BASED_CONNECTION_REQ. Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Marcel Holtmann

Bluetooth: L2CAP: Add get_peer_pid callback

2020-03-24T08:48:00+00:00

This adds a callback to read the socket pid. Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Marcel Holtmann

Bluetooth: L2CAP: Add module option to enable ECRED mode

2020-03-08T09:05:40+00:00

This should make it safe to have the code upstream without affecting stable systems since there are a few details not sort out with ECRED mode e.g: how to initiate multiple connections at once. Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Marcel Holtmann