| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
pinmux: Use sequential access to access desc->pinmux data
When two client of the same gpio call pinctrl_select_state() for the
same functionality, we are seeing NULL pointer issue while accessing
desc->mux_owner.
Let's say two processes A, B executing in pin_request() for the same pin
and process A updates the desc->mux_usecount but not yet updated the
desc->mux_owner while process B see the desc->mux_usecount which got
updated by A path and further executes strcmp and while accessing
desc->mux_owner it crashes with NULL pointer.
Serialize the access to mux related setting with a mutex lock.
cpu0 (process A) cpu1(process B)
pinctrl_select_state() { pinctrl_select_state() {
pin_request() { pin_request() {
...
....
} else {
desc->mux_usecount++;
desc->mux_usecount && strcmp(desc->mux_owner, owner)) {
if (desc->mux_usecount > 1)
return 0;
desc->mux_owner = owner;
} } |
| In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to shrink read extent node in batches
We use rwlock to protect core structure data of extent tree during
its shrink, however, if there is a huge number of extent nodes in
extent tree, during shrink of extent tree, it may hold rwlock for
a very long time, which may trigger kernel hang issue.
This patch fixes to shrink read extent node in batches, so that,
critical region of the rwlock can be shrunk to avoid its extreme
long time hold. |
| In the Linux kernel, the following vulnerability has been resolved:
net: nexthop: Increase weight to u16
In CLOS networks, as link failures occur at various points in the network,
ECMP weights of the involved nodes are adjusted to compensate. With high
fan-out of the involved nodes, and overall high number of nodes,
a (non-)ECMP weight ratio that we would like to configure does not fit into
8 bits. Instead of, say, 255:254, we might like to configure something like
1000:999. For these deployments, the 8-bit weight may not be enough.
To that end, in this patch increase the next hop weight from u8 to u16.
Increasing the width of an integral type can be tricky, because while the
code still compiles, the types may not check out anymore, and numerical
errors come up. To prevent this, the conversion was done in two steps.
First the type was changed from u8 to a single-member structure, which
invalidated all uses of the field. This allowed going through them one by
one and audit for type correctness. Then the structure was replaced with a
vanilla u16 again. This should ensure that no place was missed.
The UAPI for configuring nexthop group members is that an attribute
NHA_GROUP carries an array of struct nexthop_grp entries:
struct nexthop_grp {
__u32 id; /* nexthop id - must exist */
__u8 weight; /* weight of this nexthop */
__u8 resvd1;
__u16 resvd2;
};
The field resvd1 is currently validated and required to be zero. We can
lift this requirement and carry high-order bits of the weight in the
reserved field:
struct nexthop_grp {
__u32 id; /* nexthop id - must exist */
__u8 weight; /* weight of this nexthop */
__u8 weight_high;
__u16 resvd2;
};
Keeping the fields split this way was chosen in case an existing userspace
makes assumptions about the width of the weight field, and to sidestep any
endianness issues.
The weight field is currently encoded as the weight value minus one,
because weight of 0 is invalid. This same trick is impossible for the new
weight_high field, because zero must mean actual zero. With this in place:
- Old userspace is guaranteed to carry weight_high of 0, therefore
configuring 8-bit weights as appropriate. When dumping nexthops with
16-bit weight, it would only show the lower 8 bits. But configuring such
nexthops implies existence of userspace aware of the extension in the
first place.
- New userspace talking to an old kernel will work as long as it only
attempts to configure 8-bit weights, where the high-order bits are zero.
Old kernel will bounce attempts at configuring >8-bit weights.
Renaming reserved fields as they are allocated for some purpose is commonly
done in Linux. Whoever touches a reserved field is doing so at their own
risk. nexthop_grp::resvd1 in particular is currently used by at least
strace, however they carry an own copy of UAPI headers, and the conversion
should be trivial. A helper is provided for decoding the weight out of the
two fields. Forcing a conversion seems preferable to bending backwards and
introducing anonymous unions or whatever. |
| In the Linux kernel, the following vulnerability has been resolved:
blk-cgroup: dropping parent refcount after pd_free_fn() is done
Some cgroup policies will access parent pd through child pd even
after pd_offline_fn() is done. If pd_free_fn() for parent is called
before child, then UAF can be triggered. Hence it's better to guarantee
the order of pd_free_fn().
Currently refcount of parent blkg is dropped in __blkg_release(), which
is before pd_free_fn() is called in blkg_free_work_fn() while
blkg_free_work_fn() is called asynchronously.
This patch make sure pd_free_fn() called from removing cgroup is ordered
by delaying dropping parent refcount after calling pd_free_fn() for
child.
BTW, pd_free_fn() will also be called from blkcg_deactivate_policy()
from deleting device, and following patches will guarantee the order. |
| In the Linux kernel, the following vulnerability has been resolved:
interconnect: Fix locking for runpm vs reclaim
For cases where icc_bw_set() can be called in callbaths that could
deadlock against shrinker/reclaim, such as runpm resume, we need to
decouple the icc locking. Introduce a new icc_bw_lock for cases where
we need to serialize bw aggregation and update to decouple that from
paths that require memory allocation such as node/link creation/
destruction.
Fixes this lockdep splat:
======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc8-debug+ #554 Not tainted
------------------------------------------------------
ring0/132 is trying to acquire lock:
ffffff80871916d0 (&gmu->lock){+.+.}-{3:3}, at: a6xx_pm_resume+0xf0/0x234
but task is already holding lock:
ffffffdb5aee57e8 (dma_fence_map){++++}-{0:0}, at: msm_job_run+0x68/0x150
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (dma_fence_map){++++}-{0:0}:
__dma_fence_might_wait+0x74/0xc0
dma_resv_lockdep+0x1f4/0x2f4
do_one_initcall+0x104/0x2bc
kernel_init_freeable+0x344/0x34c
kernel_init+0x30/0x134
ret_from_fork+0x10/0x20
-> #3 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}:
fs_reclaim_acquire+0x80/0xa8
slab_pre_alloc_hook.constprop.0+0x40/0x25c
__kmem_cache_alloc_node+0x60/0x1cc
__kmalloc+0xd8/0x100
topology_parse_cpu_capacity+0x8c/0x178
get_cpu_for_node+0x88/0xc4
parse_cluster+0x1b0/0x28c
parse_cluster+0x8c/0x28c
init_cpu_topology+0x168/0x188
smp_prepare_cpus+0x24/0xf8
kernel_init_freeable+0x18c/0x34c
kernel_init+0x30/0x134
ret_from_fork+0x10/0x20
-> #2 (fs_reclaim){+.+.}-{0:0}:
__fs_reclaim_acquire+0x3c/0x48
fs_reclaim_acquire+0x54/0xa8
slab_pre_alloc_hook.constprop.0+0x40/0x25c
__kmem_cache_alloc_node+0x60/0x1cc
__kmalloc+0xd8/0x100
kzalloc.constprop.0+0x14/0x20
icc_node_create_nolock+0x4c/0xc4
icc_node_create+0x38/0x58
qcom_icc_rpmh_probe+0x1b8/0x248
platform_probe+0x70/0xc4
really_probe+0x158/0x290
__driver_probe_device+0xc8/0xe0
driver_probe_device+0x44/0x100
__driver_attach+0xf8/0x108
bus_for_each_dev+0x78/0xc4
driver_attach+0x2c/0x38
bus_add_driver+0xd0/0x1d8
driver_register+0xbc/0xf8
__platform_driver_register+0x30/0x3c
qnoc_driver_init+0x24/0x30
do_one_initcall+0x104/0x2bc
kernel_init_freeable+0x344/0x34c
kernel_init+0x30/0x134
ret_from_fork+0x10/0x20
-> #1 (icc_lock){+.+.}-{3:3}:
__mutex_lock+0xcc/0x3c8
mutex_lock_nested+0x30/0x44
icc_set_bw+0x88/0x2b4
_set_opp_bw+0x8c/0xd8
_set_opp+0x19c/0x300
dev_pm_opp_set_opp+0x84/0x94
a6xx_gmu_resume+0x18c/0x804
a6xx_pm_resume+0xf8/0x234
adreno_runtime_resume+0x2c/0x38
pm_generic_runtime_resume+0x30/0x44
__rpm_callback+0x15c/0x174
rpm_callback+0x78/0x7c
rpm_resume+0x318/0x524
__pm_runtime_resume+0x78/0xbc
adreno_load_gpu+0xc4/0x17c
msm_open+0x50/0x120
drm_file_alloc+0x17c/0x228
drm_open_helper+0x74/0x118
drm_open+0xa0/0x144
drm_stub_open+0xd4/0xe4
chrdev_open+0x1b8/0x1e4
do_dentry_open+0x2f8/0x38c
vfs_open+0x34/0x40
path_openat+0x64c/0x7b4
do_filp_open+0x54/0xc4
do_sys_openat2+0x9c/0x100
do_sys_open+0x50/0x7c
__arm64_sys_openat+0x28/0x34
invoke_syscall+0x8c/0x128
el0_svc_common.constprop.0+0xa0/0x11c
do_el0_
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to do sanity check on direct node in truncate_dnode()
syzbot reports below bug:
BUG: KASAN: slab-use-after-free in f2fs_truncate_data_blocks_range+0x122a/0x14c0 fs/f2fs/file.c:574
Read of size 4 at addr ffff88802a25c000 by task syz-executor148/5000
CPU: 1 PID: 5000 Comm: syz-executor148 Not tainted 6.4.0-rc7-syzkaller-00041-ge660abd551f1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351
print_report mm/kasan/report.c:462 [inline]
kasan_report+0x11c/0x130 mm/kasan/report.c:572
f2fs_truncate_data_blocks_range+0x122a/0x14c0 fs/f2fs/file.c:574
truncate_dnode+0x229/0x2e0 fs/f2fs/node.c:944
f2fs_truncate_inode_blocks+0x64b/0xde0 fs/f2fs/node.c:1154
f2fs_do_truncate_blocks+0x4ac/0xf30 fs/f2fs/file.c:721
f2fs_truncate_blocks+0x7b/0x300 fs/f2fs/file.c:749
f2fs_truncate.part.0+0x4a5/0x630 fs/f2fs/file.c:799
f2fs_truncate include/linux/fs.h:825 [inline]
f2fs_setattr+0x1738/0x2090 fs/f2fs/file.c:1006
notify_change+0xb2c/0x1180 fs/attr.c:483
do_truncate+0x143/0x200 fs/open.c:66
handle_truncate fs/namei.c:3295 [inline]
do_open fs/namei.c:3640 [inline]
path_openat+0x2083/0x2750 fs/namei.c:3791
do_filp_open+0x1ba/0x410 fs/namei.c:3818
do_sys_openat2+0x16d/0x4c0 fs/open.c:1356
do_sys_open fs/open.c:1372 [inline]
__do_sys_creat fs/open.c:1448 [inline]
__se_sys_creat fs/open.c:1442 [inline]
__x64_sys_creat+0xcd/0x120 fs/open.c:1442
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
The root cause is, inodeA references inodeB via inodeB's ino, once inodeA
is truncated, it calls truncate_dnode() to truncate data blocks in inodeB's
node page, it traverse mapping data from node->i.i_addr[0] to
node->i.i_addr[ADDRS_PER_BLOCK() - 1], result in out-of-boundary access.
This patch fixes to add sanity check on dnode page in truncate_dnode(),
so that, it can help to avoid triggering such issue, and once it encounters
such issue, it will record newly introduced ERROR_INVALID_NODE_REFERENCE
error into superblock, later fsck can detect such issue and try repairing.
Also, it removes f2fs_truncate_data_blocks() for cleanup due to the
function has only one caller, and uses f2fs_truncate_data_blocks_range()
instead. |
| In the Linux kernel, the following vulnerability has been resolved:
block/rq_qos: protect rq_qos apis with a new lock
commit 50e34d78815e ("block: disable the elevator int del_gendisk")
move rq_qos_exit() from disk_release() to del_gendisk(), this will
introduce some problems:
1) If rq_qos_add() is triggered by enabling iocost/iolatency through
cgroupfs, then it can concurrent with del_gendisk(), it's not safe to
write 'q->rq_qos' concurrently.
2) Activate cgroup policy that is relied on rq_qos will call
rq_qos_add() and blkcg_activate_policy(), and if rq_qos_exit() is
called in the middle, null-ptr-dereference will be triggered in
blkcg_activate_policy().
3) blkg_conf_open_bdev() can call blkdev_get_no_open() first to find the
disk, then if rq_qos_exit() from del_gendisk() is done before
rq_qos_add(), then memory will be leaked.
This patch add a new disk level mutex 'rq_qos_mutex':
1) The lock will protect rq_qos_exit() directly.
2) For wbt that doesn't relied on blk-cgroup, rq_qos_add() can only be
called from disk initialization for now because wbt can't be
destructed until rq_qos_exit(), so it's safe not to protect wbt for
now. Hoever, in case that rq_qos dynamically destruction is supported
in the furture, this patch also protect rq_qos_add() from wbt_init()
directly, this is enough because blk-sysfs already synchronize
writers with disk removal.
3) For iocost and iolatency, in order to synchronize disk removal and
cgroup configuration, the lock is held after blkdev_get_no_open()
from blkg_conf_open_bdev(), and is released in blkg_conf_exit().
In order to fix the above memory leak, disk_live() is checked after
holding the new lock. |
| In the Linux kernel, the following vulnerability has been resolved:
smc: Fix use-after-free in tcp_write_timer_handler().
With Eric's ref tracker, syzbot finally found a repro for
use-after-free in tcp_write_timer_handler() by kernel TCP
sockets. [0]
If SMC creates a kernel socket in __smc_create(), the kernel
socket is supposed to be freed in smc_clcsock_release() by
calling sock_release() when we close() the parent SMC socket.
However, at the end of smc_clcsock_release(), the kernel
socket's sk_state might not be TCP_CLOSE. This means that
we have not called inet_csk_destroy_sock() in __tcp_close()
and have not stopped the TCP timers.
The kernel socket's TCP timers can be fired later, so we
need to hold a refcnt for net as we do for MPTCP subflows
in mptcp_subflow_create_socket().
[0]:
leaked reference.
sk_alloc (./include/net/net_namespace.h:335 net/core/sock.c:2108)
inet_create (net/ipv4/af_inet.c:319 net/ipv4/af_inet.c:244)
__sock_create (net/socket.c:1546)
smc_create (net/smc/af_smc.c:3269 net/smc/af_smc.c:3284)
__sock_create (net/socket.c:1546)
__sys_socket (net/socket.c:1634 net/socket.c:1618 net/socket.c:1661)
__x64_sys_socket (net/socket.c:1672)
do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)
==================================================================
BUG: KASAN: slab-use-after-free in tcp_write_timer_handler (net/ipv4/tcp_timer.c:378 net/ipv4/tcp_timer.c:624 net/ipv4/tcp_timer.c:594)
Read of size 1 at addr ffff888052b65e0d by task syzrepro/18091
CPU: 0 PID: 18091 Comm: syzrepro Tainted: G W 6.3.0-rc4-01174-gb5d54eb5899a #7
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.amzn2022.0.1 04/01/2014
Call Trace:
<IRQ>
dump_stack_lvl (lib/dump_stack.c:107)
print_report (mm/kasan/report.c:320 mm/kasan/report.c:430)
kasan_report (mm/kasan/report.c:538)
tcp_write_timer_handler (net/ipv4/tcp_timer.c:378 net/ipv4/tcp_timer.c:624 net/ipv4/tcp_timer.c:594)
tcp_write_timer (./include/linux/spinlock.h:390 net/ipv4/tcp_timer.c:643)
call_timer_fn (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/timer.h:127 kernel/time/timer.c:1701)
__run_timers.part.0 (kernel/time/timer.c:1752 kernel/time/timer.c:2022)
run_timer_softirq (kernel/time/timer.c:2037)
__do_softirq (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/irq.h:142 kernel/softirq.c:572)
__irq_exit_rcu (kernel/softirq.c:445 kernel/softirq.c:650)
irq_exit_rcu (kernel/softirq.c:664)
sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1107 (discriminator 14))
</IRQ> |
| In the Linux kernel, the following vulnerability has been resolved:
pinctrl: freescale: Fix a memory out of bounds when num_configs is 1
The config passed in by pad wakeup is 1, when num_configs is 1,
Configuration [1] should not be fetched, which will be detected
by KASAN as a memory out of bounds condition. Modify to get
configs[1] when num_configs is 2. |
| In the Linux kernel, the following vulnerability has been resolved:
net: sched: cls_u32: Undo tcf_bind_filter if u32_replace_hw_knode
When u32_replace_hw_knode fails, we need to undo the tcf_bind_filter
operation done at u32_set_parms. |
| In the Linux kernel, the following vulnerability has been resolved:
Input: exc3000 - properly stop timer on shutdown
We need to stop the timer on driver unbind or probe failures, otherwise
we get UAF/Oops. |
| In the Linux kernel, the following vulnerability has been resolved:
can: gs_usb: fix time stamp counter initialization
If the gs_usb device driver is unloaded (or unbound) before the
interface is shut down, the USB stack first calls the struct
usb_driver::disconnect and then the struct net_device_ops::ndo_stop
callback.
In gs_usb_disconnect() all pending bulk URBs are killed, i.e. no more
RX'ed CAN frames are send from the USB device to the host. Later in
gs_can_close() a reset control message is send to each CAN channel to
remove the controller from the CAN bus. In this race window the USB
device can still receive CAN frames from the bus and internally queue
them to be send to the host.
At least in the current version of the candlelight firmware, the queue
of received CAN frames is not emptied during the reset command. After
loading (or binding) the gs_usb driver, new URBs are submitted during
the struct net_device_ops::ndo_open callback and the candlelight
firmware starts sending its already queued CAN frames to the host.
However, this scenario was not considered when implementing the
hardware timestamp function. The cycle counter/time counter
infrastructure is set up (gs_usb_timestamp_init()) after the USBs are
submitted, resulting in a NULL pointer dereference if
timecounter_cyc2time() (via the call chain:
gs_usb_receive_bulk_callback() -> gs_usb_set_timestamp() ->
gs_usb_skb_set_timestamp()) is called too early.
Move the gs_usb_timestamp_init() function before the URBs are
submitted to fix this problem.
For a comprehensive solution, we need to consider gs_usb devices with
more than 1 channel. The cycle counter/time counter infrastructure is
setup per channel, but the RX URBs are per device. Once gs_can_open()
of _a_ channel has been called, and URBs have been submitted, the
gs_usb_receive_bulk_callback() can be called for _all_ available
channels, even for channels that are not running, yet. As cycle
counter/time counter has not set up, this will again lead to a NULL
pointer dereference.
Convert the cycle counter/time counter from a "per channel" to a "per
device" functionality. Also set it up, before submitting any URBs to
the device.
Further in gs_usb_receive_bulk_callback(), don't process any URBs for
not started CAN channels, only resubmit the URB. |
| In the Linux kernel, the following vulnerability has been resolved:
f2fs: don't reset unchangable mount option in f2fs_remount()
syzbot reports a bug as below:
general protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] PREEMPT SMP KASAN
RIP: 0010:__lock_acquire+0x69/0x2000 kernel/locking/lockdep.c:4942
Call Trace:
lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5691
__raw_write_lock include/linux/rwlock_api_smp.h:209 [inline]
_raw_write_lock+0x2e/0x40 kernel/locking/spinlock.c:300
__drop_extent_tree+0x3ac/0x660 fs/f2fs/extent_cache.c:1100
f2fs_drop_extent_tree+0x17/0x30 fs/f2fs/extent_cache.c:1116
f2fs_insert_range+0x2d5/0x3c0 fs/f2fs/file.c:1664
f2fs_fallocate+0x4e4/0x6d0 fs/f2fs/file.c:1838
vfs_fallocate+0x54b/0x6b0 fs/open.c:324
ksys_fallocate fs/open.c:347 [inline]
__do_sys_fallocate fs/open.c:355 [inline]
__se_sys_fallocate fs/open.c:353 [inline]
__x64_sys_fallocate+0xbd/0x100 fs/open.c:353
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
The root cause is race condition as below:
- since it tries to remount rw filesystem, so that do_remount won't
call sb_prepare_remount_readonly to block fallocate, there may be race
condition in between remount and fallocate.
- in f2fs_remount(), default_options() will reset mount option to default
one, and then update it based on result of parse_options(), so there is
a hole which race condition can happen.
Thread A Thread B
- f2fs_fill_super
- parse_options
- clear_opt(READ_EXTENT_CACHE)
- f2fs_remount
- default_options
- set_opt(READ_EXTENT_CACHE)
- f2fs_fallocate
- f2fs_insert_range
- f2fs_drop_extent_tree
- __drop_extent_tree
- __may_extent_tree
- test_opt(READ_EXTENT_CACHE) return true
- write_lock(&et->lock) access NULL pointer
- parse_options
- clear_opt(READ_EXTENT_CACHE) |
| In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: xsk: Fix crash on regular rq reactivation
When the regular rq is reactivated after the XSK socket is closed
it could be reading stale cqes which eventually corrupts the rq.
This leads to no more traffic being received on the regular rq and a
crash on the next close or deactivation of the rq.
Kal Cuttler Conely reported this issue as a crash on the release
path when the xdpsock sample program is stopped (killed) and restarted
in sequence while traffic is running.
This patch flushes all cqes when during the rq flush. The cqe flushing
is done in the reset state of the rq. mlx5e_rq_to_ready code is moved
into the flush function to allow for this. |
| In the Linux kernel, the following vulnerability has been resolved:
coresight: Fix memory leak in acpi_buffer->pointer
There are memory leaks reported by kmemleak:
...
unreferenced object 0xffff00213c141000 (size 1024):
comm "systemd-udevd", pid 2123, jiffies 4294909467 (age 6062.160s)
hex dump (first 32 bytes):
04 00 00 00 02 00 00 00 18 10 14 3c 21 00 ff ff ...........<!...
00 00 00 00 00 00 00 00 03 00 00 00 10 00 00 00 ................
backtrace:
[<000000004b7c9001>] __kmem_cache_alloc_node+0x2f8/0x348
[<00000000b0fc7ceb>] __kmalloc+0x58/0x108
[<0000000064ff4695>] acpi_os_allocate+0x2c/0x68
[<000000007d57d116>] acpi_ut_initialize_buffer+0x54/0xe0
[<0000000024583908>] acpi_evaluate_object+0x388/0x438
[<0000000017b2e72b>] acpi_evaluate_object_typed+0xe8/0x240
[<000000005df0eac2>] coresight_get_platform_data+0x1b4/0x988 [coresight]
...
The ACPI buffer memory (buf.pointer) should be freed. But the buffer
is also used after returning from acpi_get_dsd_graph().
Move the temporary variables buf to acpi_coresight_parse_graph(),
and free it before the function return to prevent memory leak. |
| In the Linux kernel, the following vulnerability has been resolved:
ext4: avoid deadlock in fs reclaim with page writeback
Ext4 has a filesystem wide lock protecting ext4_writepages() calls to
avoid races with switching of journalled data flag or inode format. This
lock can however cause a deadlock like:
CPU0 CPU1
ext4_writepages()
percpu_down_read(sbi->s_writepages_rwsem);
ext4_change_inode_journal_flag()
percpu_down_write(sbi->s_writepages_rwsem);
- blocks, all readers block from now on
ext4_do_writepages()
ext4_init_io_end()
kmem_cache_zalloc(io_end_cachep, GFP_KERNEL)
fs_reclaim frees dentry...
dentry_unlink_inode()
iput() - last ref =>
iput_final() - inode dirty =>
write_inode_now()...
ext4_writepages() tries to acquire sbi->s_writepages_rwsem
and blocks forever
Make sure we cannot recurse into filesystem reclaim from writeback code
to avoid the deadlock. |
| In the Linux kernel, the following vulnerability has been resolved:
mtd: core: Fix refcount error in del_mtd_device()
del_mtd_device() will call of_node_put() to mtd_get_of_node(mtd), which
is mtd->dev.of_node. However, memset(&mtd->dev, 0) is called before
of_node_put(). As the result, of_node_put() won't do anything in
del_mtd_device(), and causes the refcount leak.
del_mtd_device()
memset(&mtd->dev, 0, sizeof(mtd->dev) # clear mtd->dev
of_node_put()
mtd_get_of_node(mtd) # mtd->dev is cleared, can't locate of_node
# of_node_put(NULL) won't do anything
Fix the error by caching the pointer of the device_node.
OF: ERROR: memory leak, expected refcount 1 instead of 2,
of_node_get()/of_node_put() unbalanced - destroy cset entry: attach
overlay node /spi/spi-sram@0
CPU: 3 PID: 275 Comm: python3 Tainted: G N 6.1.0-rc3+ #54
0d8a1edddf51f172ff5226989a7565c6313b08e2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x67/0x83
kobject_get+0x155/0x160
of_node_get+0x1f/0x30
of_fwnode_get+0x43/0x70
fwnode_handle_get+0x54/0x80
fwnode_get_nth_parent+0xc9/0xe0
fwnode_full_name_string+0x3f/0xa0
device_node_string+0x30f/0x750
pointer+0x598/0x7a0
vsnprintf+0x62d/0x9b0
...
cfs_overlay_release+0x30/0x90
config_item_release+0xbe/0x1a0
config_item_put+0x5e/0x80
configfs_rmdir+0x3bd/0x540
vfs_rmdir+0x18c/0x320
do_rmdir+0x198/0x330
__x64_sys_rmdir+0x2c/0x40
do_syscall_64+0x37/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
[<miquel.raynal@bootlin.com>: Light reword of the commit log] |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Do mark_chain_precision for ARG_CONST_ALLOC_SIZE_OR_ZERO
Precision markers need to be propagated whenever we have an ARG_CONST_*
style argument, as the verifier cannot consider imprecise scalars to be
equivalent for the purposes of states_equal check when such arguments
refine the return value (in this case, set mem_size for PTR_TO_MEM). The
resultant mem_size for the R0 is derived from the constant value, and if
the verifier incorrectly prunes states considering them equivalent where
such arguments exist (by seeing that both registers have reg->precise as
false in regsafe), we can end up with invalid programs passing the
verifier which can do access beyond what should have been the correct
mem_size in that explored state.
To show a concrete example of the problem:
0000000000000000 <prog>:
0: r2 = *(u32 *)(r1 + 80)
1: r1 = *(u32 *)(r1 + 76)
2: r3 = r1
3: r3 += 4
4: if r3 > r2 goto +18 <LBB5_5>
5: w2 = 0
6: *(u32 *)(r1 + 0) = r2
7: r1 = *(u32 *)(r1 + 0)
8: r2 = 1
9: if w1 == 0 goto +1 <LBB5_3>
10: r2 = -1
0000000000000058 <LBB5_3>:
11: r1 = 0 ll
13: r3 = 0
14: call bpf_ringbuf_reserve
15: if r0 == 0 goto +7 <LBB5_5>
16: r1 = r0
17: r1 += 16777215
18: w2 = 0
19: *(u8 *)(r1 + 0) = r2
20: r1 = r0
21: r2 = 0
22: call bpf_ringbuf_submit
00000000000000b8 <LBB5_5>:
23: w0 = 0
24: exit
For the first case, the single line execution's exploration will prune
the search at insn 14 for the branch insn 9's second leg as it will be
verified first using r2 = -1 (UINT_MAX), while as w1 at insn 9 will
always be 0 so at runtime we don't get error for being greater than
UINT_MAX/4 from bpf_ringbuf_reserve. The verifier during regsafe just
sees reg->precise as false for both r2 registers in both states, hence
considers them equal for purposes of states_equal.
If we propagated precise markers using the backtracking support, we
would use the precise marking to then ensure that old r2 (UINT_MAX) was
within the new r2 (1) and this would never be true, so the verification
would rightfully fail.
The end result is that the out of bounds access at instruction 19 would
be permitted without this fix.
Note that reg->precise is always set to true when user does not have
CAP_BPF (or when subprog count is greater than 1 (i.e. use of any static
or global functions)), hence this is only a problem when precision marks
need to be explicitly propagated (i.e. privileged users with CAP_BPF).
A simplified test case has been included in the next patch to prevent
future regressions. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_tables: avoid skb access on nf_stolen
When verdict is NF_STOLEN, the skb might have been freed.
When tracing is enabled, this can result in a use-after-free:
1. access to skb->nf_trace
2. access to skb->mark
3. computation of trace id
4. dump of packet payload
To avoid 1, keep a cached copy of skb->nf_trace in the
trace state struct.
Refresh this copy whenever verdict is != STOLEN.
Avoid 2 by skipping skb->mark access if verdict is STOLEN.
3 is avoided by precomputing the trace id.
Only dump the packet when verdict is not "STOLEN". |
| In the Linux kernel, the following vulnerability has been resolved:
staging: vchiq_arm: Avoid NULL ptr deref in vchiq_dump_platform_instances
vchiq_get_state() can return a NULL pointer. So handle this cases and
avoid a NULL pointer derefence in vchiq_dump_platform_instances. |
