Linux: >> Linux Kernel >> 6.1.121 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
io_uring: fix possible deadlock in io_register_iowq_max_workers()
The io_register_iowq_max_workers() function calls io_put_sq_data(),
which acquires the sqd->lock without releasing the uring_lock.
Similar to the commit 009ad9f0c6ee ("io_uring: drop ctx->uring_lock
before acquiring sqd->lock"), this can lead to a potential deadlock
situation.
To resolve this issue, the uring_lock is released before calling
io_put_sq_data(), and then it is re-acquired after the function call.
This change ensures that the locks are acquired in the correct
order, preventing the possibility of a deadlock.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
nvme-fabrics: use reserved tag for reg read/write command
In some scenarios, if too many commands are issued by nvme command in
the same time by user tasks, this may exhaust all tags of admin_q. If
a reset (nvme reset or IO timeout) occurs before these commands finish,
reconnect routine may fail to update nvme regs due to insufficient tags,
which will cause kernel hang forever. In order to workaround this issue,
maybe we can let reg_read32()/reg_read64()/reg_write32() use reserved
tags. This maybe safe for nvmf:
1. For the disable ctrl path, we will not issue connect command
2. For the enable ctrl / fw activate path, since connect and reg_xx()
are called serially.
So the reserved tags may still be enough while reg_xx() use reserved tags.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
btrfs: scrub: handle RST lookup error correctly
[BUG]
When running btrfs/060 with forced RST feature, it would crash the
following ASSERT() inside scrub_read_endio():
ASSERT(sector_nr < stripe->nr_sectors);
Before that, we would have tree dump from
btrfs_get_raid_extent_offset(), as we failed to find the RST entry for
the range.
[CAUSE]
Inside scrub_submit_extent_sector_read() every time we allocated a new
bbio we immediately called btrfs_map_block() to make sure there was some
RST range covering the scrub target.
But if btrfs_map_block() fails, we immediately call endio for the bbio,
while the bbio is newly allocated, it's completely empty.
Then inside scrub_read_endio(), we go through the bvecs to find
the sector number (as bi_sector is no longer reliable if the bio is
submitted to lower layers).
And since the bio is empty, such bvecs iteration would not find any
sector matching the sector, and return sector_nr == stripe->nr_sectors,
triggering the ASSERT().
[FIX]
Instead of calling btrfs_map_block() after allocating a new bbio, call
btrfs_map_block() first.
Since our only objective of calling btrfs_map_block() is only to update
stripe_len, there is really no need to do that after btrfs_alloc_bio().
This new timing would avoid the problem of handling empty bbio
completely, and in fact fixes a possible race window for the old code,
where if the submission thread is the only owner of the pending_io, the
scrub would never finish (since we didn't decrease the pending_io
counter).
Although the root cause of RST lookup failure still needs to be
addressed.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
bpf: Defer work in bpf_timer_cancel_and_free
Currently, the same case as previous patch (two timer callbacks trying
to cancel each other) can be invoked through bpf_map_update_elem as
well, or more precisely, freeing map elements containing timers. Since
this relies on hrtimer_cancel as well, it is prone to the same deadlock
situation as the previous patch.
It would be sufficient to use hrtimer_try_to_cancel to fix this problem,
as the timer cannot be enqueued after async_cancel_and_free. Once
async_cancel_and_free has been done, the timer must be reinitialized
before it can be armed again. The callback running in parallel trying to
arm the timer will fail, and freeing bpf_hrtimer without waiting is
sufficient (given kfree_rcu), and bpf_timer_cb will return
HRTIMER_NORESTART, preventing the timer from being rearmed again.
However, there exists a UAF scenario where the callback arms the timer
before entering this function, such that if cancellation fails (due to
timer callback invoking this routine, or the target timer callback
running concurrently). In such a case, if the timer expiration is
significantly far in the future, the RCU grace period expiration
happening before it will free the bpf_hrtimer state and along with it
the struct hrtimer, that is enqueued.
Hence, it is clear cancellation needs to occur after
async_cancel_and_free, and yet it cannot be done inline due to deadlock
issues. We thus modify bpf_timer_cancel_and_free to defer work to the
global workqueue, adding a work_struct alongside rcu_head (both used at
_different_ points of time, so can share space).
Update existing code comments to reflect the new state of affairs.
CVSS Score
7.8
EPSS Score
0.0
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
sched/deadline: Fix task_struct reference leak
During the execution of the following stress test with linux-rt:
stress-ng --cyclic 30 --timeout 30 --minimize --quiet
kmemleak frequently reported a memory leak concerning the task_struct:
unreferenced object 0xffff8881305b8000 (size 16136):
comm "stress-ng", pid 614, jiffies 4294883961 (age 286.412s)
object hex dump (first 32 bytes):
02 40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 .@..............
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
debug hex dump (first 16 bytes):
53 09 00 00 00 00 00 00 00 00 00 00 00 00 00 00 S...............
backtrace:
[<00000000046b6790>] dup_task_struct+0x30/0x540
[<00000000c5ca0f0b>] copy_process+0x3d9/0x50e0
[<00000000ced59777>] kernel_clone+0xb0/0x770
[<00000000a50befdc>] __do_sys_clone+0xb6/0xf0
[<000000001dbf2008>] do_syscall_64+0x5d/0xf0
[<00000000552900ff>] entry_SYSCALL_64_after_hwframe+0x6e/0x76
The issue occurs in start_dl_timer(), which increments the task_struct
reference count and sets a timer. The timer callback, dl_task_timer,
is supposed to decrement the reference count upon expiration. However,
if enqueue_task_dl() is called before the timer expires and cancels it,
the reference count is not decremented, leading to the leak.
This patch fixes the reference leak by ensuring the task_struct
reference count is properly decremented when the timer is canceled.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
mm/filemap: skip to create PMD-sized page cache if needed
On ARM64, HPAGE_PMD_ORDER is 13 when the base page size is 64KB. The
PMD-sized page cache can't be supported by xarray as the following error
messages indicate.
------------[ cut here ]------------
WARNING: CPU: 35 PID: 7484 at lib/xarray.c:1025 xas_split_alloc+0xf8/0x128
Modules linked in: nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib \
nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct \
nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 \
ip_set rfkill nf_tables nfnetlink vfat fat virtio_balloon drm \
fuse xfs libcrc32c crct10dif_ce ghash_ce sha2_ce sha256_arm64 \
sha1_ce virtio_net net_failover virtio_console virtio_blk failover \
dimlib virtio_mmio
CPU: 35 PID: 7484 Comm: test Kdump: loaded Tainted: G W 6.10.0-rc5-gavin+ #9
Hardware name: QEMU KVM Virtual Machine, BIOS edk2-20240524-1.el9 05/24/2024
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : xas_split_alloc+0xf8/0x128
lr : split_huge_page_to_list_to_order+0x1c4/0x720
sp : ffff800087a4f6c0
x29: ffff800087a4f6c0 x28: ffff800087a4f720 x27: 000000001fffffff
x26: 0000000000000c40 x25: 000000000000000d x24: ffff00010625b858
x23: ffff800087a4f720 x22: ffffffdfc0780000 x21: 0000000000000000
x20: 0000000000000000 x19: ffffffdfc0780000 x18: 000000001ff40000
x17: 00000000ffffffff x16: 0000018000000000 x15: 51ec004000000000
x14: 0000e00000000000 x13: 0000000000002000 x12: 0000000000000020
x11: 51ec000000000000 x10: 51ece1c0ffff8000 x9 : ffffbeb961a44d28
x8 : 0000000000000003 x7 : ffffffdfc0456420 x6 : ffff0000e1aa6eb8
x5 : 20bf08b4fe778fca x4 : ffffffdfc0456420 x3 : 0000000000000c40
x2 : 000000000000000d x1 : 000000000000000c x0 : 0000000000000000
Call trace:
xas_split_alloc+0xf8/0x128
split_huge_page_to_list_to_order+0x1c4/0x720
truncate_inode_partial_folio+0xdc/0x160
truncate_inode_pages_range+0x1b4/0x4a8
truncate_pagecache_range+0x84/0xa0
xfs_flush_unmap_range+0x70/0x90 [xfs]
xfs_file_fallocate+0xfc/0x4d8 [xfs]
vfs_fallocate+0x124/0x2e8
ksys_fallocate+0x4c/0xa0
__arm64_sys_fallocate+0x24/0x38
invoke_syscall.constprop.0+0x7c/0xd8
do_el0_svc+0xb4/0xd0
el0_svc+0x44/0x1d8
el0t_64_sync_handler+0x134/0x150
el0t_64_sync+0x17c/0x180
Fix it by skipping to allocate PMD-sized page cache when its size is
larger than MAX_PAGECACHE_ORDER. For this specific case, we will fall to
regular path where the readahead window is determined by BDI's sysfs file
(read_ahead_kb).
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
xfs: don't walk off the end of a directory data block
This adds sanity checks for xfs_dir2_data_unused and xfs_dir2_data_entry
to make sure don't stray beyond valid memory region. Before patching, the
loop simply checks that the start offset of the dup and dep is within the
range. So in a crafted image, if last entry is xfs_dir2_data_unused, we
can change dup->length to dup->length-1 and leave 1 byte of space. In the
next traversal, this space will be considered as dup or dep. We may
encounter an out of bound read when accessing the fixed members.
In the patch, we make sure that the remaining bytes large enough to hold
an unused entry before accessing xfs_dir2_data_unused and
xfs_dir2_data_unused is XFS_DIR2_DATA_ALIGN byte aligned. We also make
sure that the remaining bytes large enough to hold a dirent with a
single-byte name before accessing xfs_dir2_data_entry.
CVSS Score
7.1
EPSS Score
0.0
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: change vm->task_info handling
This patch changes the handling and lifecycle of vm->task_info object.
The major changes are:
- vm->task_info is a dynamically allocated ptr now, and its uasge is
reference counted.
- introducing two new helper funcs for task_info lifecycle management
- amdgpu_vm_get_task_info: reference counts up task_info before
returning this info
- amdgpu_vm_put_task_info: reference counts down task_info
- last put to task_info() frees task_info from the vm.
This patch also does logistical changes required for existing usage
of vm->task_info.
V2: Do not block all the prints when task_info not found (Felix)
V3: Fixed review comments from Felix
- Fix wrong indentation
- No debug message for -ENOMEM
- Add NULL check for task_info
- Do not duplicate the debug messages (ti vs no ti)
- Get first reference of task_info in vm_init(), put last
in vm_fini()
V4: Fixed review comments from Felix
- fix double reference increment in create_task_info
- change amdgpu_vm_get_task_info_pasid
- additional changes in amdgpu_gem.c while porting
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-16
In the Linux kernel, the following vulnerability has been resolved:
cpufreq: amd-pstate: fix memory leak on CPU EPP exit
The cpudata memory from kzalloc() in amd_pstate_epp_cpu_init() is
not freed in the analogous exit function, so fix that.
[ rjw: Subject and changelog edits ]
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-12
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix uninitialized ratelimit_state->lock access in __ext4_fill_super()
In the following concurrency we will access the uninitialized rs->lock:
ext4_fill_super
ext4_register_sysfs
// sysfs registered msg_ratelimit_interval_ms
// Other processes modify rs->interval to
// non-zero via msg_ratelimit_interval_ms
ext4_orphan_cleanup
ext4_msg(sb, KERN_INFO, "Errors on filesystem, "
__ext4_msg
___ratelimit(&(EXT4_SB(sb)->s_msg_ratelimit_state)
if (!rs->interval) // do nothing if interval is 0
return 1;
raw_spin_trylock_irqsave(&rs->lock, flags)
raw_spin_trylock(lock)
_raw_spin_trylock
__raw_spin_trylock
spin_acquire(&lock->dep_map, 0, 1, _RET_IP_)
lock_acquire
__lock_acquire
register_lock_class
assign_lock_key
dump_stack();
ratelimit_state_init(&sbi->s_msg_ratelimit_state, 5 * HZ, 10);
raw_spin_lock_init(&rs->lock);
// init rs->lock here
and get the following dump_stack:
=========================================================
INFO: trying to register non-static key.
The code is fine but needs lockdep annotation, or maybe
you didn't initialize this object before use?
turning off the locking correctness validator.
CPU: 12 PID: 753 Comm: mount Tainted: G E 6.7.0-rc6-next-20231222 #504
[...]
Call Trace:
dump_stack_lvl+0xc5/0x170
dump_stack+0x18/0x30
register_lock_class+0x740/0x7c0
__lock_acquire+0x69/0x13a0
lock_acquire+0x120/0x450
_raw_spin_trylock+0x98/0xd0
___ratelimit+0xf6/0x220
__ext4_msg+0x7f/0x160 [ext4]
ext4_orphan_cleanup+0x665/0x740 [ext4]
__ext4_fill_super+0x21ea/0x2b10 [ext4]
ext4_fill_super+0x14d/0x360 [ext4]
[...]
=========================================================
Normally interval is 0 until s_msg_ratelimit_state is initialized, so
___ratelimit() does nothing. But registering sysfs precedes initializing
rs->lock, so it is possible to change rs->interval to a non-zero value
via the msg_ratelimit_interval_ms interface of sysfs while rs->lock is
uninitialized, and then a call to ext4_msg triggers the problem by
accessing an uninitialized rs->lock. Therefore register sysfs after all
initializations are complete to avoid such problems.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-12