Bluetooth: RFCOMM: Validate MTU in rfcomm_apply_pn() to prevent infinite loop
Subsystems (2)
PATCH 1/1 Bluetooth: RFCOMM: Validate MTU in rfcomm_apply_pn() to prevent infinite loop
rfcomm_apply_pn() accepts the MTU value from a remote PN (Parameter Negotiation) frame without checking for zero. When the remote peer sends an MTU of zero, d->mtu is set to 0. This causes the sendmsg path to enter an infinite loop when fragmenting data, as each fragment has size == min_t(size_t, len, 0) == 0, so the remaining length never decreases. The infinite allocation of zero-length skbs exhausts all system memory.
Fix by clamping d->mtu to RFCOMM_DEFAULT_MTU when the negotiated value is zero, consistent with the initial value assigned in rfcomm_dlc_alloc().
--- net/bluetooth/rfcomm/core.c | 4 ++++ 1 file changed, 4 insertions(+)
net/bluetooth/rfcomm/core.c +4 -0
@@ -1423,6 +1423,10 @@ static int rfcomm_apply_pn(struct rfcomm_dlc *d, int cr, struct rfcomm_pn *pn) d->mtu =__le16_to_cpu (pn->mtu); +/* MTU 0 causes an infinite loop when fragmenting in sendmsg */ +if (!d->mtu) + d->mtu =RFCOMM_DEFAULT_MTU ; +if (cr && d->mtu > s->mtu) d->mtu = s->mtu;
Signature · 1 line
2.43.0
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=1069345
---Test result---
Test Summary:
CheckPatch PENDING 0.48 seconds GitLint PENDING 0.33 seconds SubjectPrefix PASS 0.09 seconds BuildKernel PASS 26.83 seconds CheckAllWarning PASS 29.62 seconds CheckSparse PASS 28.26 seconds BuildKernel32 PASS 26.29 seconds TestRunnerSetup PASS 577.55 seconds TestRunner_l2cap-tester PASS 28.22 seconds TestRunner_iso-tester FAIL 31.50 seconds TestRunner_bnep-tester PASS 6.50 seconds TestRunner_mgmt-tester FAIL 116.17 seconds TestRunner_rfcomm-tester PASS 9.57 seconds TestRunner_sco-tester FAIL 14.52 seconds TestRunner_ioctl-tester PASS 10.52 seconds TestRunner_mesh-tester FAIL 12.56 seconds TestRunner_smp-tester PASS 8.64 seconds TestRunner_userchan-tester PASS 6.93 seconds IncrementalBuild PENDING 0.95 seconds
Details
##############################
Test: CheckPatch - PENDING
Desc: Run checkpatch.pl script
Output:
##############################
Test: GitLint - PENDING
Desc: Run gitlint
Output:
##############################
Test: TestRunner_iso-tester - FAIL
Desc: Run iso-tester with test-runner
Output:
BUG: KASAN: slab-use-after-free in le_read_features_complete+0x7e/0x2b0
Total: 141, Passed: 141 (100.0%), Failed: 0, Not Run: 0
##############################
Test: TestRunner_mgmt-tester - FAIL
Desc: Run mgmt-tester with test-runner
Output:
Total: 494, Passed: 489 (99.0%), Failed: 1, Not Run: 4
Failed Test Cases
Read Exp Feature - Success Failed 0.109 seconds
##############################
Test: TestRunner_sco-tester - FAIL
Desc: Run sco-tester with test-runner
Output:
WARNING: possible circular locking dependency detected
BUG: sleeping function called from invalid context at net/core/sock.c:3782
Total: 30, Passed: 30 (100.0%), Failed: 0, Not Run: 0
##############################
Test: TestRunner_mesh-tester - FAIL
Desc: Run mesh-tester with test-runner Output:
Total: 10, Passed: 8 (80.0%), Failed: 2, Not Run: 0
Failed Test Cases
Mesh - Send cancel - 1 Timed out 2.614 seconds Mesh - Send cancel - 2 Timed out 1.994 seconds
##############################
Test: IncrementalBuild - PENDING
Desc: Incremental build with the patches in the series Output:
---
Regards,
Linux Bluetooth
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=1069345
---Test result---
Test Summary:
CheckPatch PENDING 0.55 seconds GitLint PENDING 0.42 seconds SubjectPrefix PASS 0.06 seconds BuildKernel PASS 26.13 seconds CheckAllWarning PASS 28.72 seconds CheckSparse PASS 27.52 seconds BuildKernel32 PASS 25.16 seconds TestRunnerSetup PASS 564.21 seconds TestRunner_l2cap-tester PASS 27.56 seconds TestRunner_iso-tester PASS 43.39 seconds TestRunner_bnep-tester PASS 11.38 seconds TestRunner_mgmt-tester FAIL 115.13 seconds TestRunner_rfcomm-tester PASS 9.50 seconds TestRunner_sco-tester FAIL 14.54 seconds TestRunner_ioctl-tester PASS 10.30 seconds TestRunner_mesh-tester FAIL 11.65 seconds TestRunner_smp-tester PASS 8.74 seconds TestRunner_userchan-tester PASS 6.81 seconds TestRunner_6lowpan-tester FAIL 8.82 seconds IncrementalBuild PENDING 0.43 seconds
Details
##############################
Test: CheckPatch - PENDING
Desc: Run checkpatch.pl script
Output:
##############################
Test: GitLint - PENDING
Desc: Run gitlint
Output:
##############################
Test: TestRunner_mgmt-tester - FAIL
Desc: Run mgmt-tester with test-runner Output:
Total: 494, Passed: 489 (99.0%), Failed: 1, Not Run: 4
Failed Test Cases
Read Exp Feature - Success Failed 0.107 seconds
##############################
Test: TestRunner_sco-tester - FAIL
Desc: Run sco-tester with test-runner
Output:
WARNING: possible circular locking dependency detected
7.0.0-rc2-g79a719fe1e1e #1 Not tainted
------------------------------------------------------
kworker/u5:2/117 is trying to acquire lock:ffff888002415240 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_connect_cfm+0x358/0x8d0
but task is already holding lock:ffff8880025fe220 (&conn->lock){+.+.}-{3:3}, at: sco_connect_cfm+0x22d/0x8d0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&conn->lock){+.+.}-{3:3}:
lock_acquire+0xf7/0x2c0
_raw_spin_lock+0x2a/0x40
sco_sock_connect+0x4d7/0x1280
__sys_connect+0x1a3/0x260
__x64_sys_connect+0x6e/0xb0
do_syscall_64+0xa0/0x570
entry_SYSCALL_64_after_hwframe+0x74/0x7c-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
check_prev_add+0xe9/0xc70
__lock_acquire+0x1457/0x1df0
lock_acquire+0xf7/0x2c0
lock_sock_nested+0x36/0xd0
sco_connect_cfm+0x358/0x8d0
hci_sync_conn_complete_evt+0x3d3/0x8e0
hci_event_packet+0x74f/0xb10
hci_rx_work+0x398/0xd00
process_scheduled_works+0xb16/0x1ac0
worker_thread+0x4ff/0xba0
kthread+0x368/0x490
ret_from_fork+0x498/0x7e0
ret_from_fork_asm+0x19/0x30other info that might help us debug this:
...
BUG: sleeping function called from invalid context at net/core/sock.c:3782
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 117, name: kworker/u5:2preempt_count: 1, expected: 0
RCU nest depth: 0, expected: 0
INFO: lockdep is turned off.
CPU: 0 UID: 0 PID: 117 Comm: kworker/u5:2 Not tainted 7.0.0-rc2-g79a719fe1e1e #1 PREEMPT(lazy) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Workqueue: hci0 hci_rx_work Call Trace: <TASK> dump_stack_lvl+0x49/0x60 __might_resched+0x2ea/0x500 lock_sock_nested+0x47/0xd0 ? sco_connect_cfm+0x358/0x8d0 sco_connect_cfm+0x358/0x8d0 ? hci_debugfs_create_conn+0x190/0x210 ? __pfx_sco_connect_cfm+0x10/0x10 hci_sync_conn_complete_evt+0x3d3/0x8e0 hci_event_packet+0x74f/0xb10 ? __pfx_hci_sync_conn_complete_evt+0x10/0x10 ? __pfx_hci_event_packet+0x10/0x10 ? mark_held_locks+0x49/0x80 ? lockdep_hardirqs_on_prepare+0xd4/0x180 ? _raw_spin_unlock_irqrestore+0x2c/0x50 hci_rx_work+0x398/0xd00 process_scheduled_works+0xb16/0x1ac0 ? __pfx_process_scheduled_works+0x10/0x10 ? lock_acquire+0xf7/0x2c0 ? lock_is_held_type+0x9b/0x110 ? __pfx_hci_rx_work+0x10/0x10 worker_thread+0x4ff/0xba0 ? _raw_spin_unlock_irqrestore+0x2c/0x50 ? __pfx_worker_thread+0x10/0x10 kthread+0x368/0x490 ? _raw_spin_unlock_irq+0x23/0x40 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x498/0x7e0 ? __pfx_ret_from_fork+0x10/0x10 ? __switch_to+0x9e4/0xe50 ? __switch_to_asm+0x32/0x60
...
Total: 30, Passed: 30 (100.0%), Failed: 0, Not Run: 0
##############################
Test: TestRunner_mesh-tester - FAIL
Desc: Run mesh-tester with test-runner Output:
Total: 10, Passed: 8 (80.0%), Failed: 2, Not Run: 0
Failed Test Cases
Mesh - Send cancel - 1 Timed out 1.820 seconds Mesh - Send cancel - 2 Timed out 1.996 seconds
##############################
Test: TestRunner_6lowpan-tester - FAIL
Desc: Run 6lowpan-tester with test-runner
Output:
WARNING: possible circular locking dependency detected 7.0.0-rc2-g79a719fe1e1e #1 Not tainted
------------------------------------------------------
kworker/0:0/9 is trying to acquire lock:ffff888002760940 ((wq_completion)hci0#2){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x75/0x180
but task is already holding lock:ffffffffb284d720 (rtnl_mutex){+.+.}-{4:4}, at: lowpan_unregister_netdev+0xd/0x30
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (rtnl_mutex){+.+.}-{4:4}:
lock_acquire+0xf7/0x2c0
__mutex_lock+0x16b/0x1fc0
lowpan_register_netdev+0x11/0x30
chan_ready_cb+0x836/0xd00
l2cap_recv_frame+0x6a06/0x8920
l2cap_recv_acldata+0x790/0xdf0
hci_rx_work+0x500/0xd00
process_scheduled_works+0xb16/0x1ac0
worker_thread+0x4ff/0xba0
kthread+0x368/0x490
ret_from_fork+0x498/0x7e0
ret_from_fork_asm+0x19/0x30-> #3 (&chan->lock#3/1){+.+.}-{4:4}:
lock_acquire+0xf7/0x2c0
__mutex_lock+0x16b/0x1fc0
l2cap_chan_connect+0x74e/0x1980
lowpan_control_write+0x523/0x660
full_proxy_write+0x10b/0x190
vfs_write+0x1c0/0xf60
ksys_write+0xf1/0x1d0
do_syscall_64+0xa0/0x570
entry_SYSCALL_64_after_hwframe+0x74/0x7c-> #2 (&conn->lock){+.+.}-{4:4}:
...
Total: 8, Passed: 8 (100.0%), Failed: 0, Not Run: 0
##############################
Test: IncrementalBuild - PENDING
Desc: Incremental build with the patches in the series Output:
https://github.com/bluez/bluetooth-next/pull/25/checks
---
Regards,
Linux Bluetooth
Luiz Augusto von Dentz
maintainerHi Hyunwoo,
Quoted 35 lines · Hyunwoo Kim
rfcomm_apply_pn()accepts the MTU value from a remote PN (Parameter Negotiation) frame without checking for zero. When the remote peer sends an MTU of zero,d->mtuis set to 0. This causes the sendmsg path to enter an infinite loop when fragmenting data, as each fragment has size ==min_t(size_t, len, 0)== 0, so the remaining length never decreases. The infinite allocation of zero-length skbs exhausts all system memory.Fix by clamping
d->mtutoRFCOMM_DEFAULT_MTUwhen the negotiated value is zero, consistent with the initial value assigned inrfcomm_dlc_alloc().Fixes 1da177e4c3f4 ("Linux-2.6.12-rc2")Signed-off-by Hyunwoo Kim <[email protected]>--- net/bluetooth/rfcomm/core.c | 4 ++++ 1 file changed, 4 insertions(+)net/bluetooth/rfcomm/core.c +4
-1@@ -1423,6 +1423,10 @@ static int rfcomm_apply_pn(struct rfcomm_dlc *d, int cr, struct rfcomm_pn *pn) d->mtu =__le16_to_cpu (pn->mtu); +/* MTU 0 causes an infinite loop when fragmenting in sendmsg */ +if (!d->mtu) + d->mtu =RFCOMM_DEFAULT_MTU ; +if (cr && d->mtu > s->mtu) d->mtu = s->mtu; --
Quoted 1 line
2.43.0
Looks like we never processed this one, that said I actually wonder if pn->mtu of 0 is actually valid and perhaps we should probably reject/disconnect.
Signature · 1 line
Luiz Augusto von Dentz