commit 31643d84b8c3d9c846aa0e20bc033e46c68c7e7d upstream.
With the introduction of binder_available_for_proc_work_ilocked() in
commit 1b77e9dcc3 ("ANDROID: binder: remove proc waitqueue") a binder
thread can only "wait_for_proc_work" after its thread->looper has been
marked as BINDER_LOOPER_STATE_{ENTERED|REGISTERED}.
This means an unregistered reader risks waiting indefinitely for work
since it never gets added to the proc->waiting_threads. If there are no
further references to its waitqueue either the task will hang. The same
applies to readers using the (e)poll interface.
I couldn't find the rationale behind this restriction. So this patch
restores the previous behavior of allowing unregistered threads to
"wait_for_proc_work". Note that an error message for this scenario,
which had previously become unreachable, is now re-enabled.
Fixes: 1b77e9dcc3 ("ANDROID: binder: remove proc waitqueue")
Cc: stable@vger.kernel.org
Cc: Martijn Coenen <maco@google.com>
Cc: Arve Hjønnevåg <arve@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20240711201452.2017543-1-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 229670361c29381b0e1677763590e4dbc209ecbe)
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
commit 42316941335644a98335f209daafa4c122f28983 upstream.
The type defined for the BINDER_SET_MAX_THREADS ioctl was changed from
size_t to __u32 in order to avoid incompatibility issues between 32 and
64-bit kernels. However, the internal types used to copy from user and
store the value were never updated. Use u32 to fix the inconsistency.
Fixes: a9350fc859 ("staging: android: binder: fix BINDER_SET_MAX_THREADS declaration")
Reported-by: Arve Hjønnevåg <arve@android.com>
Cc: stable@vger.kernel.org
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240421173750.3117808-1-cmllamas@google.com
[cmllamas: resolve minor conflicts due to missing commit 421518a2740f]
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit c437184be3c16f7123e5c59b4c85c1101f4dc96b)
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
[ Upstream commit 97830f3c3088638ff90b20dfba2eb4d487bf14d7 ]
In (e)poll mode, threads often depend on I/O events to determine when
data is ready for consumption. Within binder, a thread may initiate a
command via BINDER_WRITE_READ without a read buffer and then make use
of epoll_wait() or similar to consume any responses afterwards.
It is then crucial that epoll threads are signaled via wakeup when they
queue their own work. Otherwise, they risk waiting indefinitely for an
event leaving their work unhandled. What is worse, subsequent commands
won't trigger a wakeup either as the thread has pending work.
Fixes: 457b9a6f09 ("Staging: android: add binder driver")
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Martijn Coenen <maco@android.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Steven Moreland <smoreland@google.com>
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20240131215347.1808751-1-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
[ Upstream commit 148ade2c4d4f46b3ecc1ddad1c762371e8708e35 ]
This flag determines whether the thread should currently
process the work in the thread->todo worklist.
The prime usecase for this is improving the performance
of synchronous transactions: all synchronous transactions
post a BR_TRANSACTION_COMPLETE to the calling thread,
but there's no reason to return that command to userspace
right away - userspace anyway needs to wait for the reply.
Likewise, a synchronous transaction that contains a binder
object can cause a BC_ACQUIRE/BC_INCREFS to be returned to
userspace; since the caller must anyway hold a strong/weak
ref for the duration of the call, postponing these commands
until the reply comes in is not a problem.
Note that this flag is not used to determine whether a
thread can handle process work; a thread should never pick
up process work when thread work is still pending.
Before patch:
------------------------------------------------------------------
Benchmark Time CPU Iterations
------------------------------------------------------------------
BM_sendVec_binderize/4 45959 ns 20288 ns 34351
BM_sendVec_binderize/8 45603 ns 20080 ns 34909
BM_sendVec_binderize/16 45528 ns 20113 ns 34863
BM_sendVec_binderize/32 45551 ns 20122 ns 34881
BM_sendVec_binderize/64 45701 ns 20183 ns 34864
BM_sendVec_binderize/128 45824 ns 20250 ns 34576
BM_sendVec_binderize/256 45695 ns 20171 ns 34759
BM_sendVec_binderize/512 45743 ns 20211 ns 34489
BM_sendVec_binderize/1024 46169 ns 20430 ns 34081
After patch:
------------------------------------------------------------------
Benchmark Time CPU Iterations
------------------------------------------------------------------
BM_sendVec_binderize/4 42939 ns 17262 ns 40653
BM_sendVec_binderize/8 42823 ns 17243 ns 40671
BM_sendVec_binderize/16 42898 ns 17243 ns 40594
BM_sendVec_binderize/32 42838 ns 17267 ns 40527
BM_sendVec_binderize/64 42854 ns 17249 ns 40379
BM_sendVec_binderize/128 42881 ns 17288 ns 40427
BM_sendVec_binderize/256 42917 ns 17297 ns 40429
BM_sendVec_binderize/512 43184 ns 17395 ns 40411
BM_sendVec_binderize/1024 43119 ns 17357 ns 40432
Signed-off-by: Martijn Coenen <maco@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 97830f3c3088 ("binder: signal epoll threads of self-work")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
commit c6d05e0762ab276102246d24affd1e116a46aa0c upstream.
Each transaction is associated with a 'struct binder_buffer' that stores
the metadata about its buffer area. Since commit 74310e06be ("android:
binder: Move buffer out of area shared with user space") this struct is
no longer embedded within the buffer itself but is instead allocated on
the heap to prevent userspace access to this driver-exclusive info.
Unfortunately, the space of this struct is still being accounted for in
the total buffer size calculation, specifically for async transactions.
This results in an additional 104 bytes added to every async buffer
request, and this area is never used.
This wasted space can be substantial. If we consider the maximum mmap
buffer space of SZ_4M, the driver will reserve half of it for async
transactions, or 0x200000. This area should, in theory, accommodate up
to 262,144 buffers of the minimum 8-byte size. However, after adding
the extra 'sizeof(struct binder_buffer)', the total number of buffers
drops to only 18,724, which is a sad 7.14% of the actual capacity.
This patch fixes the buffer size calculation to enable the utilization
of the entire async buffer space. This is expected to reduce the number
of -ENOSPC errors that are seen on the field.
Fixes: 74310e06be ("android: binder: Move buffer out of area shared with user space")
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20231201172212.1813387-6-cmllamas@google.com
[cmllamas: fix trivial conflict with missing 261e7818f06e.]
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit e2425a67b5ed67496959d0dfb99816f5757164b0)
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
commit 9a9ab0d963621d9d12199df9817e66982582d5a5 upstream.
Task A calls binder_update_page_range() to allocate and insert pages on
a remote address space from Task B. For this, Task A pins the remote mm
via mmget_not_zero() first. This can race with Task B do_exit() and the
final mmput() refcount decrement will come from Task A.
Task A | Task B
------------------+------------------
mmget_not_zero() |
| do_exit()
| exit_mm()
| mmput()
mmput() |
exit_mmap() |
remove_vma() |
fput() |
In this case, the work of ____fput() from Task B is queued up in Task A
as TWA_RESUME. So in theory, Task A returns to userspace and the cleanup
work gets executed. However, Task A instead sleep, waiting for a reply
from Task B that never comes (it's dead).
This means the binder_deferred_release() is blocked until an unrelated
binder event forces Task A to go back to userspace. All the associated
death notifications will also be delayed until then.
In order to fix this use mmput_async() that will schedule the work in
the corresponding mm->async_put_work WQ instead of Task A.
Fixes: 457b9a6f09 ("Staging: android: add binder driver")
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20231201172212.1813387-4-cmllamas@google.com
[cmllamas: fix trivial conflict with missing d8ed45c5dcd4.]
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 95b1d336b0642198b56836b89908d07b9a0c9608)
[fix conflict due to missing commit 720c241924046aff83f5f2323232f34a30a4c281
("ANDROID: binder: change down_write to down_read")]
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
commit a0e44c64b6061dda7e00b7c458e4523e2331b739 upstream.
A transaction of type BINDER_TYPE_WEAK_HANDLE can fail to increment the
reference for a node. In this case, the target proc normally releases
the failed reference upon close as expected. However, if the target is
dying in parallel the call will race with binder_deferred_release(), so
the target could have released all of its references by now leaving the
cleanup of the new failed reference unhandled.
The transaction then ends and the target proc gets released making the
ref->proc now a dangling pointer. Later on, ref->node is closed and we
attempt to take spin_lock(&ref->proc->inner_lock), which leads to the
use-after-free bug reported below. Let's fix this by cleaning up the
failed reference on the spot instead of relying on the target to do so.
==================================================================
BUG: KASAN: use-after-free in _raw_spin_lock+0xa8/0x150
Write of size 4 at addr ffff5ca207094238 by task kworker/1:0/590
CPU: 1 PID: 590 Comm: kworker/1:0 Not tainted 5.19.0-rc8 #10
Hardware name: linux,dummy-virt (DT)
Workqueue: events binder_deferred_func
Call trace:
dump_backtrace.part.0+0x1d0/0x1e0
show_stack+0x18/0x70
dump_stack_lvl+0x68/0x84
print_report+0x2e4/0x61c
kasan_report+0xa4/0x110
kasan_check_range+0xfc/0x1a4
__kasan_check_write+0x3c/0x50
_raw_spin_lock+0xa8/0x150
binder_deferred_func+0x5e0/0x9b0
process_one_work+0x38c/0x5f0
worker_thread+0x9c/0x694
kthread+0x188/0x190
ret_from_fork+0x10/0x20
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Cc: stable <stable@kernel.org> # 4.14+
Link: https://lore.kernel.org/r/20220801182511.3371447-1-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
A transaction of type BINDER_TYPE_WEAK_HANDLE can fail to increment the
reference for a node. In this case, the target proc normally releases
the failed reference upon close as expected. However, if the target is
dying in parallel the call will race with binder_deferred_release(), so
the target could have released all of its references by now leaving the
cleanup of the new failed reference unhandled.
The transaction then ends and the target proc gets released making the
ref->proc now a dangling pointer. Later on, ref->node is closed and we
attempt to take spin_lock(&ref->proc->inner_lock), which leads to the
use-after-free bug reported below. Let's fix this by cleaning up the
failed reference on the spot instead of relying on the target to do so.
==================================================================
BUG: KASAN: use-after-free in _raw_spin_lock+0xa8/0x150
Write of size 4 at addr ffff5ca207094238 by task kworker/1:0/590
CPU: 1 PID: 590 Comm: kworker/1:0 Not tainted 5.19.0-rc8 #10
Hardware name: linux,dummy-virt (DT)
Workqueue: events binder_deferred_func
Call trace:
dump_backtrace.part.0+0x1d0/0x1e0
show_stack+0x18/0x70
dump_stack_lvl+0x68/0x84
print_report+0x2e4/0x61c
kasan_report+0xa4/0x110
kasan_check_range+0xfc/0x1a4
__kasan_check_write+0x3c/0x50
_raw_spin_lock+0xa8/0x150
binder_deferred_func+0x5e0/0x9b0
process_one_work+0x38c/0x5f0
worker_thread+0x9c/0x694
kthread+0x188/0x190
ret_from_fork+0x10/0x20
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Bug: 239630375
Link: https://lore.kernel.org/all/20220801182511.3371447-1-cmllamas@google.com/
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Change-Id: I5085dd0dc805a780a64c057e5819f82dd8f02868
(cherry picked from commit ae3fa5d16a02ba7c7b170e0e1ab56d6f0ba33964)
Changes in 4.14.261
HID: asus: Add depends on USB_HID to HID_ASUS Kconfig option
tee: handle lookup of shm with reference count 0
platform/x86: apple-gmux: use resource_size() with res
recordmcount.pl: fix typo in s390 mcount regex
selinux: initialize proto variable in selinux_ip_postroute_compat()
scsi: lpfc: Terminate string in lpfc_debugfs_nvmeio_trc_write()
net: usb: pegasus: Do not drop long Ethernet frames
NFC: st21nfca: Fix memory leak in device probe and remove
fsl/fman: Fix missing put_device() call in fman_port_probe
nfc: uapi: use kernel size_t to fix user-space builds
uapi: fix linux/nfc.h userspace compilation errors
xhci: Fresco FL1100 controller should not have BROKEN_MSI quirk set.
usb: gadget: f_fs: Clear ffs_eventfd in ffs_data_clear.
binder: fix async_free_space accounting for empty parcels
scsi: vmw_pvscsi: Set residual data length conditionally
Input: appletouch - initialize work before device registration
Input: spaceball - fix parsing of movement data packets
net: fix use-after-free in tw_timer_handler
sctp: use call_rcu to free endpoint
Linux 4.14.261
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I778bc28ac0835029328e2b503cb8fa241981c610
commit cfd0d84ba28c18b531648c9d4a35ecca89ad9901 upstream.
In 4.13, commit 74310e06be ("android: binder: Move buffer out of area shared with user space")
fixed a kernel structure visibility issue. As part of that patch,
sizeof(void *) was used as the buffer size for 0-length data payloads so
the driver could detect abusive clients sending 0-length asynchronous
transactions to a server by enforcing limits on async_free_size.
Unfortunately, on the "free" side, the accounting of async_free_space
did not add the sizeof(void *) back. The result was that up to 8-bytes of
async_free_space were leaked on every async transaction of 8-bytes or
less. These small transactions are uncommon, so this accounting issue
has gone undetected for several years.
The fix is to use "buffer_size" (the allocated buffer size) instead of
"size" (the logical buffer size) when updating the async_free_space
during the free operation. These are the same except for this
corner case of asynchronous transactions with payloads < 8 bytes.
Fixes: 74310e06be ("android: binder: Move buffer out of area shared with user space")
Signed-off-by: Todd Kjos <tkjos@google.com>
Cc: stable@vger.kernel.org # 4.14+
Link: https://lore.kernel.org/r/20211220190150.2107077-1-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Changes in 4.14.258
HID: add hid_is_usb() function to make it simpler for USB detection
HID: add USB_HID dependancy to hid-prodikeys
HID: add USB_HID dependancy to hid-chicony
HID: add USB_HID dependancy on some USB HID drivers
HID: wacom: fix problems when device is not a valid USB device
HID: check for valid USB device for many HID drivers
can: sja1000: fix use after free in ems_pcmcia_add_card()
nfc: fix potential NULL pointer deref in nfc_genl_dump_ses_done
bpf: Fix the off-by-two error in range markings
nfp: Fix memory leak in nfp_cpp_area_cache_add()
seg6: fix the iif in the IPv6 socket control block
IB/hfi1: Correct guard on eager buffer deallocation
mm: bdi: initialize bdi_min_ratio when bdi is unregistered
ALSA: ctl: Fix copy of updated id with element read/write
ALSA: pcm: oss: Fix negative period/buffer sizes
ALSA: pcm: oss: Limit the period size to 16MB
ALSA: pcm: oss: Handle missing errors in snd_pcm_oss_change_params*()
tracefs: Have new files inherit the ownership of their parent
can: pch_can: pch_can_rx_normal: fix use after free
can: m_can: Disable and ignore ELO interrupt
libata: add horkage for ASMedia 1092
wait: add wake_up_pollfree()
binder: use wake_up_pollfree()
signalfd: use wake_up_pollfree()
tracefs: Set all files to the same group ownership as the mount option
block: fix ioprio_get(IOPRIO_WHO_PGRP) vs setuid(2)
qede: validate non LSO skb length
net: cdc_ncm: Allow for dwNtbOutMaxSize to be unset or zero
net: altera: set a couple error code in probe()
net: fec: only clear interrupt of handling queue in fec_enet_rx_queue()
net, neigh: clear whole pneigh_entry at alloc time
net/qla3xxx: fix an error code in ql_adapter_up()
USB: gadget: detect too-big endpoint 0 requests
USB: gadget: zero allocate endpoint 0 buffers
usb: core: config: fix validation of wMaxPacketValue entries
xhci: Remove CONFIG_USB_DEFAULT_PERSIST to prevent xHCI from runtime suspending
usb: core: config: using bit mask instead of individual bits
iio: trigger: Fix reference counting
iio: trigger: stm32-timer: fix MODULE_ALIAS
iio: stk3310: Don't return error code in interrupt handler
iio: mma8452: Fix trigger reference couting
iio: ltr501: Don't return error code in trigger handler
iio: kxsd9: Don't return error code in trigger handler
iio: itg3200: Call iio_trigger_notify_done() on error
iio: dln2-adc: Fix lockdep complaint
iio: dln2: Check return value of devm_iio_trigger_register()
iio: adc: axp20x_adc: fix charging current reporting on AXP22x
iio: accel: kxcjk-1013: Fix possible memory leak in probe and remove
irqchip/armada-370-xp: Fix return value of armada_370_xp_msi_alloc()
irqchip/armada-370-xp: Fix support for Multi-MSI interrupts
irqchip/irq-gic-v3-its.c: Force synchronisation when issuing INVALL
irqchip: nvic: Fix offset for Interrupt Priority Offsets
Linux 4.14.258
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Iecbe5bcba94e422ef4f43e57c673b15fbc8706f8
commit a880b28a71e39013e357fd3adccd1d8a31bc69a8 upstream.
wake_up_poll() uses nr_exclusive=1, so it's not guaranteed to wake up
all exclusive waiters. Yet, POLLFREE *must* wake up all waiters. epoll
and aio poll are fortunately not affected by this, but it's very
fragile. Thus, the new function wake_up_pollfree() has been introduced.
Convert binder to use wake_up_pollfree().
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Fixes: f5cb779ba163 ("ANDROID: binder: remove waitqueue when thread exits.")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20211209010455.42744-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c21a80ca0684ec2910344d72556c816cb8940c01 upstream.
This is a partial revert of commit
29bc22ac5e5b ("binder: use euid from cred instead of using task").
Setting sender_euid using proc->cred caused some Android system test
regressions that need further investigation. It is a partial
reversion because subsequent patches rely on proc->cred.
Fixes: 29bc22ac5e5b ("binder: use euid from cred instead of using task")
Cc: stable@vger.kernel.org # 4.4+
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Change-Id: I9b1769a3510fed250bb21859ef8beebabe034c66
Link: https://lore.kernel.org/r/20211112180720.2858135-1-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 52f88693378a58094c538662ba652aff0253c4fe upstream.
Since binder was integrated with selinux, it has passed
'struct task_struct' associated with the binder_proc
to represent the source and target of transactions.
The conversion of task to SID was then done in the hook
implementations. It turns out that there are race conditions
which can result in an incorrect security context being used.
Fix by using the 'struct cred' saved during binder_open and pass
it to the selinux subsystem.
Cc: stable@vger.kernel.org # 5.14 (need backport for earlier stables)
Fixes: 79af73079d ("Add security hooks to binder and implement the hooks for SELinux.")
Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 29bc22ac5e5bc63275e850f0c8fc549e3d0e306b upstream.
Save the 'struct cred' associated with a binder process
at initial open to avoid potential race conditions
when converting to an euid.
Set a transaction's sender_euid from the 'struct cred'
saved at binder_open() instead of looking up the euid
from the binder proc's 'struct task'. This ensures
the euid is associated with the security context that
of the task that opened binder.
Cc: stable@vger.kernel.org # 4.4+
Fixes: 457b9a6f09 ("Staging: android: add binder driver")
Signed-off-by: Todd Kjos <tkjos@google.com>
Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Suggested-by: Jann Horn <jannh@google.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is a partial revert of commit
29bc22ac5e5b ("binder: use euid from cred instead of using task").
Setting sender_euid using proc->cred caused some Android system test
regressions that need further investigation. It is a partial
reversion because subsequent patches rely on proc->cred.
Fixes: 29bc22ac5e5b ("binder: use euid from cred instead of using task")
Cc: stable@vger.kernel.org # 4.4+
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Change-Id: I9b1769a3510fed250bb21859ef8beebabe034c66
Link: https://lore.kernel.org/r/20211112180720.2858135-1-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Bug: 200688826
(cherry picked from commit c21a80ca0684ec2910344d72556c816cb8940c01
git: //git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git char-misc-linus)
Signed-off-by: Todd Kjos <tkjos@google.com>
commit 52f88693378a58094c538662ba652aff0253c4fe upstream.
Since binder was integrated with selinux, it has passed
'struct task_struct' associated with the binder_proc
to represent the source and target of transactions.
The conversion of task to SID was then done in the hook
implementations. It turns out that there are race conditions
which can result in an incorrect security context being used.
Fix by using the 'struct cred' saved during binder_open and pass
it to the selinux subsystem.
Cc: stable@vger.kernel.org # 5.14 (need backport for earlier stables)
Fixes: 79af73079d ("Add security hooks to binder and implement the hooks for SELinux.")
Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Change-Id: Id7157515d2b08f11683aeb8ad9b8f1da075d34e7
Bug: 200688826
[ tkjos@ fixed minor conflict ]
Signed-off-by: Todd Kjos <tkjos@google.com>
commit 29bc22ac5e5bc63275e850f0c8fc549e3d0e306b upstream.
Save the 'struct cred' associated with a binder process
at initial open to avoid potential race conditions
when converting to an euid.
Set a transaction's sender_euid from the 'struct cred'
saved at binder_open() instead of looking up the euid
from the binder proc's 'struct task'. This ensures
the euid is associated with the security context that
of the task that opened binder.
Cc: stable@vger.kernel.org # 4.4+
Fixes: 457b9a6f09 ("Staging: android: add binder driver")
Signed-off-by: Todd Kjos <tkjos@google.com>
Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Suggested-by: Jann Horn <jannh@google.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Change-Id: I91922e7f359df5901749f1b09094c3c68d45aed4
Bug: 200688826
Signed-off-by: Todd Kjos <tkjos@google.com>
Hard-coding adj ranges to search for victims results in a few problems.
Firstly, the hard-coded adjs must be vigilantly updated to match what
userspace uses, which makes long-term support a headache. Secondly, a
full traversal of every running process must be done for each adj range,
which can turn out to be quite expensive, especially if userspace
assigns many different adj values and we want to enumerate them all.
This leads us to the final problem, which is that processes with
different adjs within the same hard-coded adj range will be treated the
same, even though they're not: the process with a higher adj is less
important, and the process with a lower adj is more important. This
could be fixed by enumerating every possible adj, but again, that would
necessitate several scans through the active process list, which is bad
for performance, especially since latency is critical here.
Since adjs are only 16 bits, and we only care about positive adjs, that
leaves us with 15 bits of the adj that matter. This is a relatively
small number of potential adjs (32,768), which makes it possible to
allocate a static array that's indexed using the adj. Each entry in this
array is a pointer to the first task_struct in a singly-linked list of
task_structs sharing an adj. A `simple_lmk_next` member is added to
task_struct to accommodate this linked list. The victim finder now
iterates downward through the array searching for linked lists of tasks,
starting from the highest adj found, so that the lowest-priority
processes are always considered first for reclaim. This fixes all of the
problems mentioned above, and now there is only one traversal through
every running process. The array itself only takes up 256 KiB of memory
on 64-bit, which is a very small price to pay for the advantages gained.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
The victims array and mm_free_lock data structures can be used very
heavily in parallel on SMP, in which case they would benefit from being
cacheline-aligned. Make it so for SMP.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
When sort() isn't provided with a custom swap function, it falls back
onto its generic implementation of just swapping one byte at a time,
which is quite slow. Since we know the type of the objects being sorted,
we can provide our own swap function which simply uses the swap() macro.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
When there aren't enough pages found, it means all of the victims that
were found need to be killed. The additional processing that attempts to
reduce the number of victims can be skipped in this case.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
When the mm_free_lock write lock is held, it means that reclaim is
either starting or ending, in which case there's nothing that needs to
be done in simple_lmk_mm_freed(). We can use a trylock here instead to
avoid blocking.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
when interrupted by a signal, binder_wait_for_work currently returns
-ERESTARTSYS. This error code is usually restricted to the kernel.
Replace this instance of -ERESTARTSYS with -EINTR.
Bug: 143717177
Test: built, booted, interrupted a worker thread within
binder_wait_for_work
Signed-off-by: Marco Ballesio <balejs@google.com>
Change-Id: I0bd1be173e0a75c917399b773046e819babb9d4b
User space needs to know if binder transactions occurred to frozen
processes. Introduce a new BINDER_GET_FROZEN ioctl and keep track of
transactions occurring to frozen proceses. Also, allow async
transactions toward frozen processes and improve error hendling.
Bug: 143717177
Test: atest testBinderLib
Signed-off-by: Marco Ballesio <balejs@google.com>
Change-Id: I9ee1c2e5fe3d4ab31fc1a137d840bd4cd38a8704
Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>
[UtsavBalar1231]
binder: Use atomic increment operations for tmp_ref increment
as per commit 91aa47009a
The most common cause of the binder transaction buffer filling up is a
client rapidly firing oneway transactions into a process, before it has
a chance to handle them. Yet the root cause of this is often hard to
debug, because either the system or the app will stop, and by that time
binder debug information we dump in bugreports is no longer relevant.
This change warns as soon as a process dips below 80% of its oneway
space (less than 100kB available in the configuration), when any one
process is responsible for either more than 50 transactions, or more
than 50% of the oneway space.
Signed-off-by: Martijn Coenen <maco@android.com>
Signed-off-by: Martijn Coenen <maco@google.com>
Acked-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20200821122544.1277051-1-maco@android.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 261e7818f06ec51e488e007f787ccd7e77272918
git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git/
char-misc-next)
Bug: 147795659
Change-Id: Idc2b03ddc779880ca4716fdae47a70df43211f25
Frozen tasks can't process binder transactions, so a way is required to
inform transmitting ends of communication failures due to the frozen
state of their receiving counterparts. Additionally, races are possible
between transitions to frozen state and binder transactions enqueued to a
specific process.
Implement BINDER_FREEZE ioctl for user space to inform the binder driver
about the intention to freeze or unfreeze a process. When the ioctl is
called, block the caller until any pending binder transactions toward the
target process are flushed. Return an error to transactions to processes
marked as frozen.
Bug: 143717177
Change-Id: Ie16f72b490bbe1785b82dee2442452f71ad7dc65
Signed-off-by: Marco Ballesio <balejs@google.com>
Co-developed-by: Todd Kjos <tkjos@google.com>
Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>
Simple LMK's reclaim thread needs to run as quickly as possible to
reduce memory allocation latency when memory pressure is high. Run it
on fast, big cluster CPUs.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>
Simple LMK uses VM pressure now, not a kswapd hook like before. Update
the Kconfig description to reflect such.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>
When PSI is enabled, lmkd in userspace will use PSI notifications to
perform low memory kills. Therefore, to ensure that Simple LMK is the
only active LMK implementation, add a !PSI dependency.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>
This aids in selecting an adequate timeout. If the timeout is hit often
and Simple LMK is killing too much, then the timeout should be
lengthened. If the timeout is rarely hit and Simple LMK is not killing
fast enough under pressure, then the timeout should be shortened.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>
Zeroing out the mm struct pointers when the timeout is hit isn't needed
because mm_free_lock prevents any readers from accessing the mm struct
pointers while clean-up occurs, and since the simple_lmk_mm_freed() loop
bound is set to zero during clean-up, there is no possibility of dying
processes ever reading stale mm struct pointers.
Therefore, it is unnecessary to clear out the mm struct pointers when
the timeout is reached. Now the only step to do when the timeout is
reached is to re-init the completion, but since reinit_completion() just
sets a struct member to zero, call reinit_completion() unconditionally
as it is faster than encapsulating it within a conditional statement.
Also take this opportunity to rename some variables and tidy up some
code indentation.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>
We already check to see if each eligible process isn't already dying, so
an RCU read lock can be used to speed things up instead of holding the
tasklist read lock.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>
We are allowed to kill any process with a positive adj, so we shouldn't
exclude any processes with adjs greater than 999. This would present a
problem with quirky applications that set their own adj score, such as
stress-ng. In the case of stress-ng, it would set its adj score to 1000
and thus exempt itself from being killed by Simple LMK. This shouldn't
be allowed; any process with a positive adj, up to the highest positive
adj possible (32767) should be killable.
Reported-by: Danny Lin <danny@kdrag0n.dev>
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>
Android 10 changed its adj assignments. Update Simple LMK to use the
new adjs, which also requires looking at each pair of adjs as a range.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>
Using kswapd's scan depth to trigger task kills is inconsistent and
unreliable. When memory pressure quickly spikes, the kswapd scan depth
trigger fails to kick off Simple LMK fast enough, causing severe lag.
Additionally, kswapd could stop scanning prematurely before reaching the
desired scan depth to trigger Simple LMK, which could also cause stalls.
To remedy this, use the vmpressure framework instead, since it provides
more consistent and accurate readings on memory pressure. This is not
very tunable though, so remove CONFIG_ANDROID_SIMPLE_LMK_AGGRESSION.
Triggering Simple LMK to kill when the reported memory pressure is 100
should yield good results on all setups.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>
Swap memory usage is important when determining what to kill, so include
it in the victim size calculation.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: UtsavBalar1231 <utsavbalar1231@gmail.com>
