Debian: >> Debian Linux >> 10.0 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
nouveau: fix instmem race condition around ptr stores
Running a lot of VK CTS in parallel against nouveau, once every
few hours you might see something like this crash.
BUG: kernel NULL pointer dereference, address: 0000000000000008
PGD 8000000114e6e067 P4D 8000000114e6e067 PUD 109046067 PMD 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 7 PID: 53891 Comm: deqp-vk Not tainted 6.8.0-rc6+ #27
Hardware name: Gigabyte Technology Co., Ltd. Z390 I AORUS PRO WIFI/Z390 I AORUS PRO WIFI-CF, BIOS F8 11/05/2021
RIP: 0010:gp100_vmm_pgt_mem+0xe3/0x180 [nouveau]
Code: c7 48 01 c8 49 89 45 58 85 d2 0f 84 95 00 00 00 41 0f b7 46 12 49 8b 7e 08 89 da 42 8d 2c f8 48 8b 47 08 41 83 c7 01 48 89 ee <48> 8b 40 08 ff d0 0f 1f 00 49 8b 7e 08 48 89 d9 48 8d 75 04 48 c1
RSP: 0000:ffffac20c5857838 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 00000000004d8001 RCX: 0000000000000001
RDX: 00000000004d8001 RSI: 00000000000006d8 RDI: ffffa07afe332180
RBP: 00000000000006d8 R08: ffffac20c5857ad0 R09: 0000000000ffff10
R10: 0000000000000001 R11: ffffa07af27e2de0 R12: 000000000000001c
R13: ffffac20c5857ad0 R14: ffffa07a96fe9040 R15: 000000000000001c
FS: 00007fe395eed7c0(0000) GS:ffffa07e2c980000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 000000011febe001 CR4: 00000000003706f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
...
? gp100_vmm_pgt_mem+0xe3/0x180 [nouveau]
? gp100_vmm_pgt_mem+0x37/0x180 [nouveau]
nvkm_vmm_iter+0x351/0xa20 [nouveau]
? __pfx_nvkm_vmm_ref_ptes+0x10/0x10 [nouveau]
? __pfx_gp100_vmm_pgt_mem+0x10/0x10 [nouveau]
? __pfx_gp100_vmm_pgt_mem+0x10/0x10 [nouveau]
? __lock_acquire+0x3ed/0x2170
? __pfx_gp100_vmm_pgt_mem+0x10/0x10 [nouveau]
nvkm_vmm_ptes_get_map+0xc2/0x100 [nouveau]
? __pfx_nvkm_vmm_ref_ptes+0x10/0x10 [nouveau]
? __pfx_gp100_vmm_pgt_mem+0x10/0x10 [nouveau]
nvkm_vmm_map_locked+0x224/0x3a0 [nouveau]
Adding any sort of useful debug usually makes it go away, so I hand
wrote the function in a line, and debugged the asm.
Every so often pt->memory->ptrs is NULL. This ptrs ptr is set in
the nv50_instobj_acquire called from nvkm_kmap.
If Thread A and Thread B both get to nv50_instobj_acquire around
the same time, and Thread A hits the refcount_set line, and in
lockstep thread B succeeds at refcount_inc_not_zero, there is a
chance the ptrs value won't have been stored since refcount_set
is unordered. Force a memory barrier here, I picked smp_mb, since
we want it on all CPUs and it's write followed by a read.
v2: use paired smp_rmb/smp_wmb.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-05-01
In the Linux kernel, the following vulnerability has been resolved:
crypto: qat - resolve race condition during AER recovery
During the PCI AER system's error recovery process, the kernel driver
may encounter a race condition with freeing the reset_data structure's
memory. If the device restart will take more than 10 seconds the function
scheduling that restart will exit due to a timeout, and the reset_data
structure will be freed. However, this data structure is used for
completion notification after the restart is completed, which leads
to a UAF bug.
This results in a KFENCE bug notice.
BUG: KFENCE: use-after-free read in adf_device_reset_worker+0x38/0xa0 [intel_qat]
Use-after-free read at 0x00000000bc56fddf (in kfence-#142):
adf_device_reset_worker+0x38/0xa0 [intel_qat]
process_one_work+0x173/0x340
To resolve this race condition, the memory associated to the container
of the work_struct is freed on the worker if the timeout expired,
otherwise on the function that schedules the worker.
The timeout detection can be done by checking if the caller is
still waiting for completion or not by using completion_done() function.
CVSS Score
7.0
EPSS Score
0.001
Published
2024-05-01
In the Linux kernel, the following vulnerability has been resolved:
KVM: Always flush async #PF workqueue when vCPU is being destroyed
Always flush the per-vCPU async #PF workqueue when a vCPU is clearing its
completion queue, e.g. when a VM and all its vCPUs is being destroyed.
KVM must ensure that none of its workqueue callbacks is running when the
last reference to the KVM _module_ is put. Gifting a reference to the
associated VM prevents the workqueue callback from dereferencing freed
vCPU/VM memory, but does not prevent the KVM module from being unloaded
before the callback completes.
Drop the misguided VM refcount gifting, as calling kvm_put_kvm() from
async_pf_execute() if kvm_put_kvm() flushes the async #PF workqueue will
result in deadlock. async_pf_execute() can't return until kvm_put_kvm()
finishes, and kvm_put_kvm() can't return until async_pf_execute() finishes:
WARNING: CPU: 8 PID: 251 at virt/kvm/kvm_main.c:1435 kvm_put_kvm+0x2d/0x320 [kvm]
Modules linked in: vhost_net vhost vhost_iotlb tap kvm_intel kvm irqbypass
CPU: 8 PID: 251 Comm: kworker/8:1 Tainted: G W 6.6.0-rc1-e7af8d17224a-x86/gmem-vm #119
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
Workqueue: events async_pf_execute [kvm]
RIP: 0010:kvm_put_kvm+0x2d/0x320 [kvm]
Call Trace:
<TASK>
async_pf_execute+0x198/0x260 [kvm]
process_one_work+0x145/0x2d0
worker_thread+0x27e/0x3a0
kthread+0xba/0xe0
ret_from_fork+0x2d/0x50
ret_from_fork_asm+0x11/0x20
</TASK>
---[ end trace 0000000000000000 ]---
INFO: task kworker/8:1:251 blocked for more than 120 seconds.
Tainted: G W 6.6.0-rc1-e7af8d17224a-x86/gmem-vm #119
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/8:1 state:D stack:0 pid:251 ppid:2 flags:0x00004000
Workqueue: events async_pf_execute [kvm]
Call Trace:
<TASK>
__schedule+0x33f/0xa40
schedule+0x53/0xc0
schedule_timeout+0x12a/0x140
__wait_for_common+0x8d/0x1d0
__flush_work.isra.0+0x19f/0x2c0
kvm_clear_async_pf_completion_queue+0x129/0x190 [kvm]
kvm_arch_destroy_vm+0x78/0x1b0 [kvm]
kvm_put_kvm+0x1c1/0x320 [kvm]
async_pf_execute+0x198/0x260 [kvm]
process_one_work+0x145/0x2d0
worker_thread+0x27e/0x3a0
kthread+0xba/0xe0
ret_from_fork+0x2d/0x50
ret_from_fork_asm+0x11/0x20
</TASK>
If kvm_clear_async_pf_completion_queue() actually flushes the workqueue,
then there's no need to gift async_pf_execute() a reference because all
invocations of async_pf_execute() will be forced to complete before the
vCPU and its VM are destroyed/freed. And that in turn fixes the module
unloading bug as __fput() won't do module_put() on the last vCPU reference
until the vCPU has been freed, e.g. if closing the vCPU file also puts the
last reference to the KVM module.
Note that kvm_check_async_pf_completion() may also take the work item off
the completion queue and so also needs to flush the work queue, as the
work will not be seen by kvm_clear_async_pf_completion_queue(). Waiting
on the workqueue could theoretically delay a vCPU due to waiting for the
work to complete, but that's a very, very small chance, and likely a very
small delay. kvm_arch_async_page_present_queued() unconditionally makes a
new request, i.e. will effectively delay entering the guest, so the
remaining work is really just:
trace_kvm_async_pf_completed(addr, cr2_or_gpa);
__kvm_vcpu_wake_up(vcpu);
mmput(mm);
and mmput() can't drop the last reference to the page tables if the vCPU is
still alive, i.e. the vCPU won't get stuck tearing down page tables.
Add a helper to do the flushing, specifically to deal with "wakeup all"
work items, as they aren't actually work items, i.e. are never placed in a
workqueue. Trying to flush a bogus workqueue entry rightly makes
__flush_work() complain (kudos to whoever added that sanity check).
Note, commit 5f6de5cbebee ("KVM: Prevent module exit until al
---truncated---
CVSS Score
7.0
EPSS Score
0.0
Published
2024-05-01
In the Linux kernel, the following vulnerability has been resolved:
clk: qcom: gcc-ipq8074: fix terminating of frequency table arrays
The frequency table arrays are supposed to be terminated with an
empty element. Add such entry to the end of the arrays where it
is missing in order to avoid possible out-of-bound access when
the table is traversed by functions like qcom_find_freq() or
qcom_find_freq_floor().
Only compile tested.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-05-01
In the Linux kernel, the following vulnerability has been resolved:
clk: qcom: gcc-ipq6018: fix terminating of frequency table arrays
The frequency table arrays are supposed to be terminated with an
empty element. Add such entry to the end of the arrays where it
is missing in order to avoid possible out-of-bound access when
the table is traversed by functions like qcom_find_freq() or
qcom_find_freq_floor().
Only compile tested.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-05-01
In the Linux kernel, the following vulnerability has been resolved:
fat: fix uninitialized field in nostale filehandles
When fat_encode_fh_nostale() encodes file handle without a parent it
stores only first 10 bytes of the file handle. However the length of the
file handle must be a multiple of 4 so the file handle is actually 12
bytes long and the last two bytes remain uninitialized. This is not
great at we potentially leak uninitialized information with the handle
to userspace. Properly initialize the full handle length.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-05-01
In the Linux kernel, the following vulnerability has been resolved:
nfs: fix UAF in direct writes
In production we have been hitting the following warning consistently
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 17 PID: 1800359 at lib/refcount.c:28 refcount_warn_saturate+0x9c/0xe0
Workqueue: nfsiod nfs_direct_write_schedule_work [nfs]
RIP: 0010:refcount_warn_saturate+0x9c/0xe0
PKRU: 55555554
Call Trace:
<TASK>
? __warn+0x9f/0x130
? refcount_warn_saturate+0x9c/0xe0
? report_bug+0xcc/0x150
? handle_bug+0x3d/0x70
? exc_invalid_op+0x16/0x40
? asm_exc_invalid_op+0x16/0x20
? refcount_warn_saturate+0x9c/0xe0
nfs_direct_write_schedule_work+0x237/0x250 [nfs]
process_one_work+0x12f/0x4a0
worker_thread+0x14e/0x3b0
? ZSTD_getCParams_internal+0x220/0x220
kthread+0xdc/0x120
? __btf_name_valid+0xa0/0xa0
ret_from_fork+0x1f/0x30
This is because we're completing the nfs_direct_request twice in a row.
The source of this is when we have our commit requests to submit, we
process them and send them off, and then in the completion path for the
commit requests we have
if (nfs_commit_end(cinfo.mds))
nfs_direct_write_complete(dreq);
However since we're submitting asynchronous requests we sometimes have
one that completes before we submit the next one, so we end up calling
complete on the nfs_direct_request twice.
The only other place we use nfs_generic_commit_list() is in
__nfs_commit_inode, which wraps this call in a
nfs_commit_begin();
nfs_commit_end();
Which is a common pattern for this style of completion handling, one
that is also repeated in the direct code with get_dreq()/put_dreq()
calls around where we process events as well as in the completion paths.
Fix this by using the same pattern for the commit requests.
Before with my 200 node rocksdb stress running this warning would pop
every 10ish minutes. With my patch the stress test has been running for
several hours without popping.
CVSS Score
7.8
EPSS Score
0.0
Published
2024-05-01
In the Linux kernel, the following vulnerability has been resolved:
mm: swap: fix race between free_swap_and_cache() and swapoff()
There was previously a theoretical window where swapoff() could run and
teardown a swap_info_struct while a call to free_swap_and_cache() was
running in another thread. This could cause, amongst other bad
possibilities, swap_page_trans_huge_swapped() (called by
free_swap_and_cache()) to access the freed memory for swap_map.
This is a theoretical problem and I haven't been able to provoke it from a
test case. But there has been agreement based on code review that this is
possible (see link below).
Fix it by using get_swap_device()/put_swap_device(), which will stall
swapoff(). There was an extra check in _swap_info_get() to confirm that
the swap entry was not free. This isn't present in get_swap_device()
because it doesn't make sense in general due to the race between getting
the reference and swapoff. So I've added an equivalent check directly in
free_swap_and_cache().
Details of how to provoke one possible issue (thanks to David Hildenbrand
for deriving this):
--8<-----
__swap_entry_free() might be the last user and result in
"count == SWAP_HAS_CACHE".
swapoff->try_to_unuse() will stop as soon as soon as si->inuse_pages==0.
So the question is: could someone reclaim the folio and turn
si->inuse_pages==0, before we completed swap_page_trans_huge_swapped().
Imagine the following: 2 MiB folio in the swapcache. Only 2 subpages are
still references by swap entries.
Process 1 still references subpage 0 via swap entry.
Process 2 still references subpage 1 via swap entry.
Process 1 quits. Calls free_swap_and_cache().
-> count == SWAP_HAS_CACHE
[then, preempted in the hypervisor etc.]
Process 2 quits. Calls free_swap_and_cache().
-> count == SWAP_HAS_CACHE
Process 2 goes ahead, passes swap_page_trans_huge_swapped(), and calls
__try_to_reclaim_swap().
__try_to_reclaim_swap()->folio_free_swap()->delete_from_swap_cache()->
put_swap_folio()->free_swap_slot()->swapcache_free_entries()->
swap_entry_free()->swap_range_free()->
...
WRITE_ONCE(si->inuse_pages, si->inuse_pages - nr_entries);
What stops swapoff to succeed after process 2 reclaimed the swap cache
but before process1 finished its call to swap_page_trans_huge_swapped()?
--8<-----
CVSS Score
5.5
EPSS Score
0.0
Published
2024-05-01
In the Linux kernel, the following vulnerability has been resolved:
clk: qcom: mmcc-apq8084: fix terminating of frequency table arrays
The frequency table arrays are supposed to be terminated with an
empty element. Add such entry to the end of the arrays where it
is missing in order to avoid possible out-of-bound access when
the table is traversed by functions like qcom_find_freq() or
qcom_find_freq_floor().
Only compile tested.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-05-01
In the Linux kernel, the following vulnerability has been resolved:
wireguard: netlink: access device through ctx instead of peer
The previous commit fixed a bug that led to a NULL peer->device being
dereferenced. It's actually easier and faster performance-wise to
instead get the device from ctx->wg. This semantically makes more sense
too, since ctx->wg->peer_allowedips.seq is compared with
ctx->allowedips_seq, basing them both in ctx. This also acts as a
defence in depth provision against freed peers.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-05-01