kernel/linux.git/net/bluetooth/rfcomm, branch v5.10.259

Bluetooth: Consolidate code around sk_alloc into a helper function

2026-06-19T11:21:45+00:00

[ Upstream commit 6bfa273e533d7b25eee3d74e28a7fe8e6a8e7a93 ] This consolidates code around sk_alloc into bt_sock_alloc which does take care of common initialization. Signed-off-by: Luiz Augusto von Dentz Stable-dep-of: e83f5e24da74 ("Bluetooth: serialize accept_q access") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

Bluetooth: fix UAF in l2cap_sock_cleanup_listen() vs l2cap_conn_del()

2026-06-19T11:21:44+00:00

[ Upstream commit ab1513597c6cf17cd1ad2a21e3b045421b48e022 ] bt_accept_dequeue() unlinks a not-yet-accepted child from the parent accept queue and release_sock()s it before returning, so the returned sk has no caller reference and is unlocked. l2cap_sock_cleanup_listen() walks these children on listening-socket close. A concurrent HCI disconnect drives hci_rx_work -> l2cap_conn_del() which runs l2cap_chan_del() + l2cap_sock_kill() and frees the child sk and its l2cap_chan; cleanup_listen() then uses both: BUG: KASAN: slab-use-after-free in l2cap_sock_kill l2cap_sock_kill / l2cap_sock_cleanup_listen / __x64_sys_close Freed by: l2cap_conn_del -> l2cap_sock_close_cb -> l2cap_sock_kill This is distinct from the two fixes already in this area: commit e83f5e24da741 ("Bluetooth: serialize accept_q access") serialises the accept_q list/poll and takes temporary refs inside bt_accept_dequeue(), and CVE-2025-39860 serialises the userspace close()/accept() race by calling cleanup_listen() under lock_sock() in l2cap_sock_release(). Neither covers l2cap_conn_del() running from hci_rx_work, so this UAF still reproduces on current bluetooth/master. Take the reference at the source: bt_accept_dequeue() does sock_hold() while sk is still locked, before release_sock(); callers sock_put(). cleanup_listen() pins the chan with l2cap_chan_hold_unless_zero() under a brief child sk lock (serialising vs l2cap_sock_teardown_cb()), drops it before l2cap_chan_lock(), and skips a duplicate l2cap_sock_kill() on SOCK_DEAD. conn->lock is not taken here: cleanup_listen() runs under the parent sk lock and that would invert conn->lock -> chan->lock -> sk_lock (lockdep). KASAN/SMP: an unprivileged listen/close vs HCI-disconnect race produced 12 use-after-free reports per run before this change; 0, and no lockdep report, over 1600+ raced iterations after it on bluetooth/master. Fixes: 15f02b910562 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode") Cc: stable@vger.kernel.org Reported-by: Siwei Zhang Reviewed-by: Siwei Zhang Signed-off-by: Safa Karakuş Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

Bluetooth: RFCOMM: hold listener socket in rfcomm_connect_ind()

2026-06-19T11:21:34+00:00

[ Upstream commit 43c441edacf953b39517a44f5e5e10a93618b226 ] rfcomm_get_sock_by_channel() scans rfcomm_sk_list under the list lock, but returns the selected listener after dropping that lock without taking a reference. rfcomm_connect_ind() then locks the listener, queues a child socket on it, and may notify it after unlocking it. The buggy scenario involves two paths, with each column showing the order within that path: rfcomm_connect_ind(): listener close: 1. Find parent in 1. close() enters rfcomm_get_sock_by_channel() rfcomm_sock_release(). 2. Drop rfcomm_sk_list.lock 2. rfcomm_sock_shutdown() without pinning parent. closes the listener. 3. Call lock_sock(parent) and 3. rfcomm_sock_kill() bt_accept_enqueue(parent, unlinks and puts parent. sk, true). 4. Read parent flags and may 4. parent can be freed. call sk_state_change(). If close wins the race, parent can be freed before rfcomm_connect_ind() reaches lock_sock(), bt_accept_enqueue(), or the deferred-setup callback. Take a reference on the listener before leaving rfcomm_sk_list.lock. After lock_sock() succeeds, recheck that it is still in BT_LISTEN before queueing a child, cache the deferred-setup bit while the parent is locked, and drop the reference after the last parent use. KASAN reported a slab-use-after-free in lock_sock_nested() from rfcomm_connect_ind(), with the freeing stack going through rfcomm_sock_kill() and rfcomm_sock_release(). Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Zhang Cen Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin

Bluetooth: RFCOMM: Fix not validating setsockopt user input

2025-02-01T17:22:33+00:00

commit a97de7bff13b1cc825c1b1344eaed8d6c2d3e695 upstream. syzbot reported rfcomm_sock_setsockopt_old() is copying data without checking user input length. BUG: KASAN: slab-out-of-bounds in copy_from_sockptr_offset include/linux/sockptr.h:49 [inline] BUG: KASAN: slab-out-of-bounds in copy_from_sockptr include/linux/sockptr.h:55 [inline] BUG: KASAN: slab-out-of-bounds in rfcomm_sock_setsockopt_old net/bluetooth/rfcomm/sock.c:632 [inline] BUG: KASAN: slab-out-of-bounds in rfcomm_sock_setsockopt+0x893/0xa70 net/bluetooth/rfcomm/sock.c:673 Read of size 4 at addr ffff8880209a8bc3 by task syz-executor632/5064 Fixes: 9f2c8a03fbb3 ("Bluetooth: Replace RFCOMM link mode with security level") Fixes: bb23c0ab8246 ("Bluetooth: Add support for deferring RFCOMM connection setup") Reported-by: syzbot Signed-off-by: Eric Dumazet Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin Signed-off-by: Keerthana K Signed-off-by: Greg Kroah-Hartman

Bluetooth: Fix type of len in rfcomm_sock_getsockopt{,_old}()

2024-12-14T18:48:09+00:00

commit 5fe6caa62b07fd39cd6a28acc8f92ba2955e11a6 upstream. Commit 9bf4e919ccad worked around an issue introduced after an innocuous optimisation change in LLVM main: > len is defined as an 'int' because it is assigned from > '__user int *optlen'. However, it is clamped against the result of > sizeof(), which has a type of 'size_t' ('unsigned long' for 64-bit > platforms). This is done with min_t() because min() requires compatible > types, which results in both len and the result of sizeof() being casted > to 'unsigned int', meaning len changes signs and the result of sizeof() > is truncated. From there, len is passed to copy_to_user(), which has a > third parameter type of 'unsigned long', so it is widened and changes > signs again. This excessive casting in combination with the KCSAN > instrumentation causes LLVM to fail to eliminate the __bad_copy_from() > call, failing the build. The same issue occurs in rfcomm in functions rfcomm_sock_getsockopt and rfcomm_sock_getsockopt_old. Change the type of len to size_t in both rfcomm_sock_getsockopt and rfcomm_sock_getsockopt_old and replace min_t() with min(). Cc: stable@vger.kernel.org Co-authored-by: Aleksei Vetrov Improves: 9bf4e919ccad ("Bluetooth: Fix type of len in {l2cap,sco}_sock_getsockopt_old()") Link: https://github.com/ClangBuiltLinux/linux/issues/2007 Link: https://github.com/llvm/llvm-project/issues/85647 Signed-off-by: Andrej Shadura Reviewed-by: Nathan Chancellor Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Greg Kroah-Hartman

Bluetooth: RFCOMM: FIX possible deadlock in rfcomm_sk_state_change

2024-10-17T13:08:34+00:00

[ Upstream commit 08d1914293dae38350b8088980e59fbc699a72fe ] rfcomm_sk_state_change attempts to use sock_lock so it must never be called with it locked but rfcomm_sock_ioctl always attempt to lock it causing the following trace: ====================================================== WARNING: possible circular locking dependency detected 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Not tainted ------------------------------------------------------ syz-executor386/5093 is trying to acquire lock: ffff88807c396258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1671 [inline] ffff88807c396258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sk_state_change+0x5b/0x310 net/bluetooth/rfcomm/sock.c:73 but task is already holding lock: ffff88807badfd28 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x226/0x6a0 net/bluetooth/rfcomm/core.c:491 Reported-by: syzbot+d7ce59b06b3eb14fd218@syzkaller.appspotmail.com Tested-by: syzbot+d7ce59b06b3eb14fd218@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d7ce59b06b3eb14fd218 Fixes: 3241ad820dbb ("[Bluetooth] Add timestamp support to L2CAP, RFCOMM and SCO") Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin

Bluetooth: rfcomm: Fix null-ptr-deref in rfcomm_check_security

2024-03-26T22:21:47+00:00

[ Upstream commit 2535b848fa0f42ddff3e5255cf5e742c9b77bb26 ] During our fuzz testing of the connection and disconnection process at the RFCOMM layer, we discovered this bug. By comparing the packets from a normal connection and disconnection process with the testcase that triggered a KASAN report. We analyzed the cause of this bug as follows: 1. In the packets captured during a normal connection, the host sends a `Read Encryption Key Size` type of `HCI_CMD` packet (Command Opcode: 0x1408) to the controller to inquire the length of encryption key.After receiving this packet, the controller immediately replies with a Command Completepacket (Event Code: 0x0e) to return the Encryption Key Size. 2. In our fuzz test case, the timing of the controller's response to this packet was delayed to an unexpected point: after the RFCOMM and L2CAP layers had disconnected but before the HCI layer had disconnected. 3. After receiving the Encryption Key Size Response at the time described in point 2, the host still called the rfcomm_check_security function. However, by this time `struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;` had already been released, and when the function executed `return hci_conn_security(conn->hcon, d->sec_level, auth_type, d->out);`, specifically when accessing `conn->hcon`, a null-ptr-deref error occurred. To fix this bug, check if `sk->sk_state` is BT_CLOSED before calling rfcomm_recv_frame in rfcomm_process_rx. Signed-off-by: Yuxuan Hu <20373622@buaa.edu.cn> Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin

Bluetooth: RFCOMM: don't call kfree_skb() under spin_lock_irqsave()

2023-01-14T09:15:45+00:00

[ Upstream commit 0ba18967d4544955b2eff2fbc4f2a8750c4df90a ] It is not allowed to call kfree_skb() from hardware interrupt context or with interrupts being disabled. So replace kfree_skb() with dev_kfree_skb_irq() under spin_lock_irqsave(). Fixes: 81be03e026dc ("Bluetooth: RFCOMM: Replace use of memcpy_from_msg with bt_skb_sendmmsg") Signed-off-by: Yang Yingliang Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin

Bluetooth: Fix passing NULL to PTR_ERR

2022-07-29T15:19:26+00:00

commit 266191aa8d14b84958aaeb5e96ee4e97839e3d87 upstream. Passing NULL to PTR_ERR will result in 0 (success), also since the likes of bt_skb_sendmsg does never return NULL it is safe to replace the instances of IS_ERR_OR_NULL with IS_ERR when checking its return. Reported-by: Dan Carpenter Tested-by: Tedd Ho-Jeong An Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Marcel Holtmann Cc: Harshit Mogalapalli Signed-off-by: Greg Kroah-Hartman

Bluetooth: RFCOMM: Replace use of memcpy_from_msg with bt_skb_sendmmsg

2022-07-29T15:19:26+00:00

commit 81be03e026dc0c16dc1c64e088b2a53b73caa895 upstream. This makes use of bt_skb_sendmmsg instead using memcpy_from_msg which is not considered safe to be used when lock_sock is held. Also make rfcomm_dlc_send handle skb with fragments and queue them all atomically. Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Marcel Holtmann Cc: Harshit Mogalapalli Signed-off-by: Greg Kroah-Hartman