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CVSS v3.1 |
In the Linux kernel, the following vulnerability has been resolved:
bpf: Tell memcg to use allow_spinning=false path in bpf_timer_init()
Currently, calling bpf_map_kmalloc_node() from __bpf_async_init() can
cause various locking issues; see the following stack trace (edited for
style) as one example:
...
[10.011566] do_raw_spin_lock.cold
[10.011570] try_to_wake_up (5) double-acquiring the same
[10.011575] kick_pool rq_lock, causing a hardlockup
[10.011579] __queue_work
[10.011582] queue_work_on
[10.011585] kernfs_notify
[10.011589] cgroup_file_notify
[10.011593] try_charge_memcg (4) memcg accounting raises an
[10.011597] obj_cgroup_charge_pages MEMCG_MAX event
[10.011599] obj_cgroup_charge_account
[10.011600] __memcg_slab_post_alloc_hook
[10.011603] __kmalloc_node_noprof
...
[10.011611] bpf_map_kmalloc_node
[10.011612] __bpf_async_init
[10.011615] bpf_timer_init (3) BPF calls bpf_timer_init()
[10.011617] bpf_prog_xxxxxxxxxxxxxxxx_fcg_runnable
[10.011619] bpf__sched_ext_ops_runnable
[10.011620] enqueue_task_scx (2) BPF runs with rq_lock held
[10.011622] enqueue_task
[10.011626] ttwu_do_activate
[10.011629] sched_ttwu_pending (1) grabs rq_lock
...
The above was reproduced on bpf-next (b338cf849ec8) by modifying
./tools/sched_ext/scx_flatcg.bpf.c to call bpf_timer_init() during
ops.runnable(), and hacking the memcg accounting code a bit to make
a bpf_timer_init() call more likely to raise an MEMCG_MAX event.
We have also run into other similar variants (both internally and on
bpf-next), including double-acquiring cgroup_file_kn_lock, the same
worker_pool::lock, etc.
As suggested by Shakeel, fix this by using __GFP_HIGH instead of
GFP_ATOMIC in __bpf_async_init(), so that e.g. if try_charge_memcg()
raises an MEMCG_MAX event, we call __memcg_memory_event() with
@allow_spinning=false and avoid calling cgroup_file_notify() there.
Depends on mm patch
"memcg: skip cgroup_file_notify if spinning is not allowed":
https://lore.kernel.org/bpf/20250905201606.66198-1-shakeel.butt@linux.dev/
v0 approach s/bpf_map_kmalloc_node/bpf_mem_alloc/
https://lore.kernel.org/bpf/20250905061919.439648-1-yepeilin@google.com/
v1 approach:
https://lore.kernel.org/bpf/20250905234547.862249-1-yepeilin@google.com/ |
In the Linux kernel, the following vulnerability has been resolved:
tracing/osnoise: Fix null-ptr-deref in bitmap_parselist()
A crash was observed with the following output:
BUG: kernel NULL pointer dereference, address: 0000000000000010
Oops: Oops: 0000 [#1] SMP NOPTI
CPU: 2 UID: 0 PID: 92 Comm: osnoise_cpus Not tainted 6.17.0-rc4-00201-gd69eb204c255 #138 PREEMPT(voluntary)
RIP: 0010:bitmap_parselist+0x53/0x3e0
Call Trace:
<TASK>
osnoise_cpus_write+0x7a/0x190
vfs_write+0xf8/0x410
? do_sys_openat2+0x88/0xd0
ksys_write+0x60/0xd0
do_syscall_64+0xa4/0x260
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
This issue can be reproduced by below code:
fd=open("/sys/kernel/debug/tracing/osnoise/cpus", O_WRONLY);
write(fd, "0-2", 0);
When user pass 'count=0' to osnoise_cpus_write(), kmalloc() will return
ZERO_SIZE_PTR (16) and cpulist_parse() treat it as a normal value, which
trigger the null pointer dereference. Add check for the parameter 'count'. |
In the Linux kernel, the following vulnerability has been resolved:
dmaengine: idxd: Remove improper idxd_free
The call to idxd_free() introduces a duplicate put_device() leading to a
reference count underflow:
refcount_t: underflow; use-after-free.
WARNING: CPU: 15 PID: 4428 at lib/refcount.c:28 refcount_warn_saturate+0xbe/0x110
...
Call Trace:
<TASK>
idxd_remove+0xe4/0x120 [idxd]
pci_device_remove+0x3f/0xb0
device_release_driver_internal+0x197/0x200
driver_detach+0x48/0x90
bus_remove_driver+0x74/0xf0
pci_unregister_driver+0x2e/0xb0
idxd_exit_module+0x34/0x7a0 [idxd]
__do_sys_delete_module.constprop.0+0x183/0x280
do_syscall_64+0x54/0xd70
entry_SYSCALL_64_after_hwframe+0x76/0x7e
The idxd_unregister_devices() which is invoked at the very beginning of
idxd_remove(), already takes care of the necessary put_device() through the
following call path:
idxd_unregister_devices() -> device_unregister() -> put_device()
In addition, when CONFIG_DEBUG_KOBJECT_RELEASE is enabled, put_device() may
trigger asynchronous cleanup via schedule_delayed_work(). If idxd_free() is
called immediately after, it can result in a use-after-free.
Remove the improper idxd_free() to avoid both the refcount underflow and
potential memory corruption during module unload. |
In the Linux kernel, the following vulnerability has been resolved:
libceph: fix invalid accesses to ceph_connection_v1_info
There is a place where generic code in messenger.c is reading and
another place where it is writing to con->v1 union member without
checking that the union member is active (i.e. msgr1 is in use).
On 64-bit systems, con->v1.auth_retry overlaps with con->v2.out_iter,
so such a read is almost guaranteed to return a bogus value instead of
0 when msgr2 is in use. This ends up being fairly benign because the
side effect is just the invalidation of the authorizer and successive
fetching of new tickets.
con->v1.connect_seq overlaps with con->v2.conn_bufs and the fact that
it's being written to can cause more serious consequences, but luckily
it's not something that happens often. |
In the Linux kernel, the following vulnerability has been resolved:
mm/damon/sysfs: fix use-after-free in state_show()
state_show() reads kdamond->damon_ctx without holding damon_sysfs_lock.
This allows a use-after-free race:
CPU 0 CPU 1
----- -----
state_show() damon_sysfs_turn_damon_on()
ctx = kdamond->damon_ctx; mutex_lock(&damon_sysfs_lock);
damon_destroy_ctx(kdamond->damon_ctx);
kdamond->damon_ctx = NULL;
mutex_unlock(&damon_sysfs_lock);
damon_is_running(ctx); /* ctx is freed */
mutex_lock(&ctx->kdamond_lock); /* UAF */
(The race can also occur with damon_sysfs_kdamonds_rm_dirs() and
damon_sysfs_kdamond_release(), which free or replace the context under
damon_sysfs_lock.)
Fix by taking damon_sysfs_lock before dereferencing the context, mirroring
the locking used in pid_show().
The bug has existed since state_show() first accessed kdamond->damon_ctx. |
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: fix recursive semaphore deadlock in fiemap call
syzbot detected a OCFS2 hang due to a recursive semaphore on a
FS_IOC_FIEMAP of the extent list on a specially crafted mmap file.
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115
rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185
__down_write_common kernel/locking/rwsem.c:1317 [inline]
__down_write kernel/locking/rwsem.c:1326 [inline]
down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1591
ocfs2_page_mkwrite+0x2ff/0xc40 fs/ocfs2/mmap.c:142
do_page_mkwrite+0x14d/0x310 mm/memory.c:3361
wp_page_shared mm/memory.c:3762 [inline]
do_wp_page+0x268d/0x5800 mm/memory.c:3981
handle_pte_fault mm/memory.c:6068 [inline]
__handle_mm_fault+0x1033/0x5440 mm/memory.c:6195
handle_mm_fault+0x40a/0x8e0 mm/memory.c:6364
do_user_addr_fault+0x764/0x1390 arch/x86/mm/fault.c:1387
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline]
RIP: 0010:raw_copy_to_user arch/x86/include/asm/uaccess_64.h:147 [inline]
RIP: 0010:_inline_copy_to_user include/linux/uaccess.h:197 [inline]
RIP: 0010:_copy_to_user+0x85/0xb0 lib/usercopy.c:26
Code: e8 00 bc f7 fc 4d 39 fc 72 3d 4d 39 ec 77 38 e8 91 b9 f7 fc 4c 89
f7 89 de e8 47 25 5b fd 0f 01 cb 4c 89 ff 48 89 d9 4c 89 f6 <f3> a4 0f
1f 00 48 89 cb 0f 01 ca 48 89 d8 5b 41 5c 41 5d 41 5e 41
RSP: 0018:ffffc9000403f950 EFLAGS: 00050256
RAX: ffffffff84c7f101 RBX: 0000000000000038 RCX: 0000000000000038
RDX: 0000000000000000 RSI: ffffc9000403f9e0 RDI: 0000200000000060
RBP: ffffc9000403fa90 R08: ffffc9000403fa17 R09: 1ffff92000807f42
R10: dffffc0000000000 R11: fffff52000807f43 R12: 0000200000000098
R13: 00007ffffffff000 R14: ffffc9000403f9e0 R15: 0000200000000060
copy_to_user include/linux/uaccess.h:225 [inline]
fiemap_fill_next_extent+0x1c0/0x390 fs/ioctl.c:145
ocfs2_fiemap+0x888/0xc90 fs/ocfs2/extent_map.c:806
ioctl_fiemap fs/ioctl.c:220 [inline]
do_vfs_ioctl+0x1173/0x1430 fs/ioctl.c:532
__do_sys_ioctl fs/ioctl.c:596 [inline]
__se_sys_ioctl+0x82/0x170 fs/ioctl.c:584
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5f13850fd9
RSP: 002b:00007ffe3b3518b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007f5f13850fd9
RDX: 0000200000000040 RSI: 00000000c020660b RDI: 0000000000000004
RBP: 6165627472616568 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe3b3518f0
R13: 00007ffe3b351b18 R14: 431bde82d7b634db R15: 00007f5f1389a03b
ocfs2_fiemap() takes a read lock of the ip_alloc_sem semaphore (since
v2.6.22-527-g7307de80510a) and calls fiemap_fill_next_extent() to read the
extent list of this running mmap executable. The user supplied buffer to
hold the fiemap information page faults calling ocfs2_page_mkwrite() which
will take a write lock (since v2.6.27-38-g00dc417fa3e7) of the same
semaphore. This recursive semaphore will hold filesystem locks and causes
a hang of the fileystem.
The ip_alloc_sem protects the inode extent list and size. Release the
read semphore before calling fiemap_fill_next_extent() in ocfs2_fiemap()
and ocfs2_fiemap_inline(). This does an unnecessary semaphore lock/unlock
on the last extent but simplifies the error path. |
In the Linux kernel, the following vulnerability has been resolved:
ceph: always call ceph_shift_unused_folios_left()
The function ceph_process_folio_batch() sets folio_batch entries to
NULL, which is an illegal state. Before folio_batch_release() crashes
due to this API violation, the function ceph_shift_unused_folios_left()
is supposed to remove those NULLs from the array.
However, since commit ce80b76dd327 ("ceph: introduce
ceph_process_folio_batch() method"), this shifting doesn't happen
anymore because the "for" loop got moved to ceph_process_folio_batch(),
and now the `i` variable that remains in ceph_writepages_start()
doesn't get incremented anymore, making the shifting effectively
unreachable much of the time.
Later, commit 1551ec61dc55 ("ceph: introduce ceph_submit_write()
method") added more preconditions for doing the shift, replacing the
`i` check (with something that is still just as broken):
- if ceph_process_folio_batch() fails, shifting never happens
- if ceph_move_dirty_page_in_page_array() was never called (because
ceph_process_folio_batch() has returned early for some of various
reasons), shifting never happens
- if `processed_in_fbatch` is zero (because ceph_process_folio_batch()
has returned early for some of the reasons mentioned above or
because ceph_move_dirty_page_in_page_array() has failed), shifting
never happens
Since those two commits, any problem in ceph_process_folio_batch()
could crash the kernel, e.g. this way:
BUG: kernel NULL pointer dereference, address: 0000000000000034
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 0 P4D 0
Oops: Oops: 0002 [#1] SMP NOPTI
CPU: 172 UID: 0 PID: 2342707 Comm: kworker/u778:8 Not tainted 6.15.10-cm4all1-es #714 NONE
Hardware name: Dell Inc. PowerEdge R7615/0G9DHV, BIOS 1.6.10 12/08/2023
Workqueue: writeback wb_workfn (flush-ceph-1)
RIP: 0010:folios_put_refs+0x85/0x140
Code: 83 c5 01 39 e8 7e 76 48 63 c5 49 8b 5c c4 08 b8 01 00 00 00 4d 85 ed 74 05 41 8b 44 ad 00 48 8b 15 b0 >
RSP: 0018:ffffb880af8db778 EFLAGS: 00010207
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000003
RDX: ffffe377cc3b0000 RSI: 0000000000000000 RDI: ffffb880af8db8c0
RBP: 0000000000000000 R08: 000000000000007d R09: 000000000102b86f
R10: 0000000000000001 R11: 00000000000000ac R12: ffffb880af8db8c0
R13: 0000000000000000 R14: 0000000000000000 R15: ffff9bd262c97000
FS: 0000000000000000(0000) GS:ffff9c8efc303000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000034 CR3: 0000000160958004 CR4: 0000000000770ef0
PKRU: 55555554
Call Trace:
<TASK>
ceph_writepages_start+0xeb9/0x1410
The crash can be reproduced easily by changing the
ceph_check_page_before_write() return value to `-E2BIG`.
(Interestingly, the crash happens only if `huge_zero_folio` has
already been allocated; without `huge_zero_folio`,
is_huge_zero_folio(NULL) returns true and folios_put_refs() skips NULL
entries instead of dereferencing them. That makes reproducing the bug
somewhat unreliable. See
https://lore.kernel.org/20250826231626.218675-1-max.kellermann@ionos.com
for a discussion of this detail.)
My suggestion is to move the ceph_shift_unused_folios_left() to right
after ceph_process_folio_batch() to ensure it always gets called to
fix up the illegal folio_batch state. |
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix subvolume deletion lockup caused by inodes xarray race
There is a race condition between inode eviction and inode caching that
can cause a live struct btrfs_inode to be missing from the root->inodes
xarray. Specifically, there is a window during evict() between the inode
being unhashed and deleted from the xarray. If btrfs_iget() is called
for the same inode in that window, it will be recreated and inserted
into the xarray, but then eviction will delete the new entry, leaving
nothing in the xarray:
Thread 1 Thread 2
---------------------------------------------------------------
evict()
remove_inode_hash()
btrfs_iget_path()
btrfs_iget_locked()
btrfs_read_locked_inode()
btrfs_add_inode_to_root()
destroy_inode()
btrfs_destroy_inode()
btrfs_del_inode_from_root()
__xa_erase
In turn, this can cause issues for subvolume deletion. Specifically, if
an inode is in this lost state, and all other inodes are evicted, then
btrfs_del_inode_from_root() will call btrfs_add_dead_root() prematurely.
If the lost inode has a delayed_node attached to it, then when
btrfs_clean_one_deleted_snapshot() calls btrfs_kill_all_delayed_nodes(),
it will loop forever because the delayed_nodes xarray will never become
empty (unless memory pressure forces the inode out). We saw this
manifest as soft lockups in production.
Fix it by only deleting the xarray entry if it matches the given inode
(using __xa_cmpxchg()). |
In the Linux kernel, the following vulnerability has been resolved:
kernfs: Fix UAF in polling when open file is released
A use-after-free (UAF) vulnerability was identified in the PSI (Pressure
Stall Information) monitoring mechanism:
BUG: KASAN: slab-use-after-free in psi_trigger_poll+0x3c/0x140
Read of size 8 at addr ffff3de3d50bd308 by task systemd/1
psi_trigger_poll+0x3c/0x140
cgroup_pressure_poll+0x70/0xa0
cgroup_file_poll+0x8c/0x100
kernfs_fop_poll+0x11c/0x1c0
ep_item_poll.isra.0+0x188/0x2c0
Allocated by task 1:
cgroup_file_open+0x88/0x388
kernfs_fop_open+0x73c/0xaf0
do_dentry_open+0x5fc/0x1200
vfs_open+0xa0/0x3f0
do_open+0x7e8/0xd08
path_openat+0x2fc/0x6b0
do_filp_open+0x174/0x368
Freed by task 8462:
cgroup_file_release+0x130/0x1f8
kernfs_drain_open_files+0x17c/0x440
kernfs_drain+0x2dc/0x360
kernfs_show+0x1b8/0x288
cgroup_file_show+0x150/0x268
cgroup_pressure_write+0x1dc/0x340
cgroup_file_write+0x274/0x548
Reproduction Steps:
1. Open test/cpu.pressure and establish epoll monitoring
2. Disable monitoring: echo 0 > test/cgroup.pressure
3. Re-enable monitoring: echo 1 > test/cgroup.pressure
The race condition occurs because:
1. When cgroup.pressure is disabled (echo 0 > cgroup.pressure), it:
- Releases PSI triggers via cgroup_file_release()
- Frees of->priv through kernfs_drain_open_files()
2. While epoll still holds reference to the file and continues polling
3. Re-enabling (echo 1 > cgroup.pressure) accesses freed of->priv
epolling disable/enable cgroup.pressure
fd=open(cpu.pressure)
while(1)
...
epoll_wait
kernfs_fop_poll
kernfs_get_active = true echo 0 > cgroup.pressure
... cgroup_file_show
kernfs_show
// inactive kn
kernfs_drain_open_files
cft->release(of);
kfree(ctx);
...
kernfs_get_active = false
echo 1 > cgroup.pressure
kernfs_show
kernfs_activate_one(kn);
kernfs_fop_poll
kernfs_get_active = true
cgroup_file_poll
psi_trigger_poll
// UAF
...
end: close(fd)
To address this issue, introduce kernfs_get_active_of() for kernfs open
files to obtain active references. This function will fail if the open file
has been released. Replace kernfs_get_active() with kernfs_get_active_of()
to prevent further operations on released file descriptors. |
In the Linux kernel, the following vulnerability has been resolved:
drm/msm/a4xx: fix error handling in a4xx_gpu_init()
This code returns 1 on error instead of a negative error. It leads to
an Oops in the caller. A second problem is that the check for
"if (ret != -ENODATA)" cannot be true because "ret" is set to 1. |
In the Linux kernel, the following vulnerability has been resolved:
iio: buffer: Fix file related error handling in IIO_BUFFER_GET_FD_IOCTL
If we fail to copy the just created file descriptor to userland, we
try to clean up by putting back 'fd' and freeing 'ib'. The code uses
put_unused_fd() for the former which is wrong, as the file descriptor
was already published by fd_install() which gets called internally by
anon_inode_getfd().
This makes the error handling code leaving a half cleaned up file
descriptor table around and a partially destructed 'file' object,
allowing userland to play use-after-free tricks on us, by abusing
the still usable fd and making the code operate on a dangling
'file->private_data' pointer.
Instead of leaving the kernel in a partially corrupted state, don't
attempt to explicitly clean up and leave this to the process exit
path that'll release any still valid fds, including the one created
by the previous call to anon_inode_getfd(). Simply return -EFAULT to
indicate the error. |
In the Linux kernel, the following vulnerability has been resolved:
phy: ti: Fix missing sentinel for clk_div_table
_get_table_maxdiv() tries to access "clk_div_table" array out of bound
defined in phy-j721e-wiz.c. Add a sentinel entry to prevent
the following global-out-of-bounds error reported by enabling KASAN.
[ 9.552392] BUG: KASAN: global-out-of-bounds in _get_maxdiv+0xc0/0x148
[ 9.558948] Read of size 4 at addr ffff8000095b25a4 by task kworker/u4:1/38
[ 9.565926]
[ 9.567441] CPU: 1 PID: 38 Comm: kworker/u4:1 Not tainted 5.16.0-116492-gdaadb3bd0e8d-dirty #360
[ 9.576242] Hardware name: Texas Instruments J721e EVM (DT)
[ 9.581832] Workqueue: events_unbound deferred_probe_work_func
[ 9.587708] Call trace:
[ 9.590174] dump_backtrace+0x20c/0x218
[ 9.594038] show_stack+0x18/0x68
[ 9.597375] dump_stack_lvl+0x9c/0xd8
[ 9.601062] print_address_description.constprop.0+0x78/0x334
[ 9.606830] kasan_report+0x1f0/0x260
[ 9.610517] __asan_load4+0x9c/0xd8
[ 9.614030] _get_maxdiv+0xc0/0x148
[ 9.617540] divider_determine_rate+0x88/0x488
[ 9.622005] divider_round_rate_parent+0xc8/0x124
[ 9.626729] wiz_clk_div_round_rate+0x54/0x68
[ 9.631113] clk_core_determine_round_nolock+0x124/0x158
[ 9.636448] clk_core_round_rate_nolock+0x68/0x138
[ 9.641260] clk_core_set_rate_nolock+0x268/0x3a8
[ 9.645987] clk_set_rate+0x50/0xa8
[ 9.649499] cdns_sierra_phy_init+0x88/0x248
[ 9.653794] phy_init+0x98/0x108
[ 9.657046] cdns_pcie_enable_phy+0xa0/0x170
[ 9.661340] cdns_pcie_init_phy+0x250/0x2b0
[ 9.665546] j721e_pcie_probe+0x4b8/0x798
[ 9.669579] platform_probe+0x8c/0x108
[ 9.673350] really_probe+0x114/0x630
[ 9.677037] __driver_probe_device+0x18c/0x220
[ 9.681505] driver_probe_device+0xac/0x150
[ 9.685712] __device_attach_driver+0xec/0x170
[ 9.690178] bus_for_each_drv+0xf0/0x158
[ 9.694124] __device_attach+0x184/0x210
[ 9.698070] device_initial_probe+0x14/0x20
[ 9.702277] bus_probe_device+0xec/0x100
[ 9.706223] deferred_probe_work_func+0x124/0x180
[ 9.710951] process_one_work+0x4b0/0xbc0
[ 9.714983] worker_thread+0x74/0x5d0
[ 9.718668] kthread+0x214/0x230
[ 9.721919] ret_from_fork+0x10/0x20
[ 9.725520]
[ 9.727032] The buggy address belongs to the variable:
[ 9.732183] clk_div_table+0x24/0x440 |
In the Linux kernel, the following vulnerability has been resolved:
x86/fpu: Ensure shadow stack is active before "getting" registers
The x86 shadow stack support has its own set of registers. Those registers
are XSAVE-managed, but they are "supervisor state components" which means
that userspace can not touch them with XSAVE/XRSTOR. It also means that
they are not accessible from the existing ptrace ABI for XSAVE state.
Thus, there is a new ptrace get/set interface for it.
The regset code that ptrace uses provides an ->active() handler in
addition to the get/set ones. For shadow stack this ->active() handler
verifies that shadow stack is enabled via the ARCH_SHSTK_SHSTK bit in the
thread struct. The ->active() handler is checked from some call sites of
the regset get/set handlers, but not the ptrace ones. This was not
understood when shadow stack support was put in place.
As a result, both the set/get handlers can be called with
XFEATURE_CET_USER in its init state, which would cause get_xsave_addr() to
return NULL and trigger a WARN_ON(). The ssp_set() handler luckily has an
ssp_active() check to avoid surprising the kernel with shadow stack
behavior when the kernel is not ready for it (ARCH_SHSTK_SHSTK==0). That
check just happened to avoid the warning.
But the ->get() side wasn't so lucky. It can be called with shadow stacks
disabled, triggering the warning in practice, as reported by Christina
Schimpe:
WARNING: CPU: 5 PID: 1773 at arch/x86/kernel/fpu/regset.c:198 ssp_get+0x89/0xa0
[...]
Call Trace:
<TASK>
? show_regs+0x6e/0x80
? ssp_get+0x89/0xa0
? __warn+0x91/0x150
? ssp_get+0x89/0xa0
? report_bug+0x19d/0x1b0
? handle_bug+0x46/0x80
? exc_invalid_op+0x1d/0x80
? asm_exc_invalid_op+0x1f/0x30
? __pfx_ssp_get+0x10/0x10
? ssp_get+0x89/0xa0
? ssp_get+0x52/0xa0
__regset_get+0xad/0xf0
copy_regset_to_user+0x52/0xc0
ptrace_regset+0x119/0x140
ptrace_request+0x13c/0x850
? wait_task_inactive+0x142/0x1d0
? do_syscall_64+0x6d/0x90
arch_ptrace+0x102/0x300
[...]
Ensure that shadow stacks are active in a thread before looking them up
in the XSAVE buffer. Since ARCH_SHSTK_SHSTK and user_ssp[SHSTK_EN] are
set at the same time, the active check ensures that there will be
something to find in the XSAVE buffer.
[ dhansen: changelog/subject tweaks ] |
NVIDIA NeMo Framework contains a vulnerability where a user could cause a deserialization of untrusted data by remote code execution. A successful exploit of this vulnerability might lead to code execution and data tampering. |
NVIDIA NeMo Framework contains a vulnerability where an attacker could cause an improper limitation of a pathname to a restricted directory by an arbitrary file write. A successful exploit of this vulnerability might lead to code execution and data tampering. |
NVIDIA NeMo Framework contains a vulnerability where a user could cause an improper control of generation of code by remote code execution. A successful exploit of this vulnerability might lead to code execution and data tampering. |
NVIDIA NeMo library for all platforms contains a vulnerability in the model loading component, where an attacker could cause code injection by loading .nemo files with maliciously crafted metadata. A successful exploit of this vulnerability may lead to remote code execution and data tampering. |
In the Linux kernel, the following vulnerability has been resolved:
userfaultfd: fix a race between writeprotect and exit_mmap()
A race is possible when a process exits, its VMAs are removed by
exit_mmap() and at the same time userfaultfd_writeprotect() is called.
The race was detected by KASAN on a development kernel, but it appears
to be possible on vanilla kernels as well.
Use mmget_not_zero() to prevent the race as done in other userfaultfd
operations. |
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: fix data corruption after conversion from inline format
Commit 6dbf7bb55598 ("fs: Don't invalidate page buffers in
block_write_full_page()") uncovered a latent bug in ocfs2 conversion
from inline inode format to a normal inode format.
The code in ocfs2_convert_inline_data_to_extents() attempts to zero out
the whole cluster allocated for file data by grabbing, zeroing, and
dirtying all pages covering this cluster. However these pages are
beyond i_size, thus writeback code generally ignores these dirty pages
and no blocks were ever actually zeroed on the disk.
This oversight was fixed by commit 693c241a5f6a ("ocfs2: No need to zero
pages past i_size.") for standard ocfs2 write path, inline conversion
path was apparently forgotten; the commit log also has a reasoning why
the zeroing actually is not needed.
After commit 6dbf7bb55598, things became worse as writeback code stopped
invalidating buffers on pages beyond i_size and thus these pages end up
with clean PageDirty bit but with buffers attached to these pages being
still dirty. So when a file is converted from inline format, then
writeback triggers, and then the file is grown so that these pages
become valid, the invalid dirtiness state is preserved,
mark_buffer_dirty() does nothing on these pages (buffers are already
dirty) but page is never written back because it is clean. So data
written to these pages is lost once pages are reclaimed.
Simple reproducer for the problem is:
xfs_io -f -c "pwrite 0 2000" -c "pwrite 2000 2000" -c "fsync" \
-c "pwrite 4000 2000" ocfs2_file
After unmounting and mounting the fs again, you can observe that end of
'ocfs2_file' has lost its contents.
Fix the problem by not doing the pointless zeroing during conversion
from inline format similarly as in the standard write path.
[akpm@linux-foundation.org: fix whitespace, per Joseph] |
In the Linux kernel, the following vulnerability has been resolved:
ice: Avoid crash from unnecessary IDA free
In the remove path, there is an attempt to free the aux_idx IDA whether
it was allocated or not. This can potentially cause a crash when
unloading the driver on systems that do not initialize support for RDMA.
But, this free cannot be gated by the status bit for RDMA, since it is
allocated if the driver detects support for RDMA at probe time, but the
driver can enter into a state where RDMA is not supported after the IDA
has been allocated at probe time and this would lead to a memory leak.
Initialize aux_idx to an invalid value and check for a valid value when
unloading to determine if an IDA free is necessary. |