Linux: >> Linux Kernel >> 6.6.63 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
drm/nouveau: Fix WARN_ON in nouveau_fence_context_kill()
Nouveau is mostly designed in a way that it's expected that fences only
ever get signaled through nouveau_fence_signal(). However, in at least
one other place, nouveau_fence_done(), can signal fences, too. If that
happens (race) a signaled fence remains in the pending list for a while,
until it gets removed by nouveau_fence_update().
Should nouveau_fence_context_kill() run in the meantime, this would be
a bug because the function would attempt to set an error code on an
already signaled fence.
Have nouveau_fence_context_kill() check for a fence being signaled.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
btrfs: adjust subpage bit start based on sectorsize
When running machines with 64k page size and a 16k nodesize we started
seeing tree log corruption in production. This turned out to be because
we were not writing out dirty blocks sometimes, so this in fact affects
all metadata writes.
When writing out a subpage EB we scan the subpage bitmap for a dirty
range. If the range isn't dirty we do
bit_start++;
to move onto the next bit. The problem is the bitmap is based on the
number of sectors that an EB has. So in this case, we have a 64k
pagesize, 16k nodesize, but a 4k sectorsize. This means our bitmap is 4
bits for every node. With a 64k page size we end up with 4 nodes per
page.
To make this easier this is how everything looks
[0 16k 32k 48k ] logical address
[0 4 8 12 ] radix tree offset
[ 64k page ] folio
[ 16k eb ][ 16k eb ][ 16k eb ][ 16k eb ] extent buffers
[ | | | | | | | | | | | | | | | | ] bitmap
Now we use all of our addressing based on fs_info->sectorsize_bits, so
as you can see the above our 16k eb->start turns into radix entry 4.
When we find a dirty range for our eb, we correctly do bit_start +=
sectors_per_node, because if we start at bit 0, the next bit for the
next eb is 4, to correspond to eb->start 16k.
However if our range is clean, we will do bit_start++, which will now
put us offset from our radix tree entries.
In our case, assume that the first time we check the bitmap the block is
not dirty, we increment bit_start so now it == 1, and then we loop
around and check again. This time it is dirty, and we go to find that
start using the following equation
start = folio_start + bit_start * fs_info->sectorsize;
so in the case above, eb->start 0 is now dirty, and we calculate start
as
0 + 1 * fs_info->sectorsize = 4096
4096 >> 12 = 1
Now we're looking up the radix tree for 1, and we won't find an eb.
What's worse is now we're using bit_start == 1, so we do bit_start +=
sectors_per_node, which is now 5. If that eb is dirty we will run into
the same thing, we will look at an offset that is not populated in the
radix tree, and now we're skipping the writeout of dirty extent buffers.
The best fix for this is to not use sectorsize_bits to address nodes,
but that's a larger change. Since this is a fs corruption problem fix
it simply by always using sectors_per_node to increment the start bit.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
sch_htb: make htb_qlen_notify() idempotent
htb_qlen_notify() always deactivates the HTB class and in fact could
trigger a warning if it is already deactivated. Therefore, it is not
idempotent and not friendly to its callers, like fq_codel_dequeue().
Let's make it idempotent to ease qdisc_tree_reduce_backlog() callers'
life.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
octeon_ep: Fix host hang issue during device reboot
When the host loses heartbeat messages from the device,
the driver calls the device-specific ndo_stop function,
which frees the resources. If the driver is unloaded in
this scenario, it calls ndo_stop again, attempting to free
resources that have already been freed, leading to a host
hang issue. To resolve this, dev_close should be called
instead of the device-specific stop function.dev_close
internally calls ndo_stop to stop the network interface
and performs additional cleanup tasks. During the driver
unload process, if the device is already down, ndo_stop
is not called.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
net_sched: drr: Fix double list add in class with netem as child qdisc
As described in Gerrard's report [1], there are use cases where a netem
child qdisc will make the parent qdisc's enqueue callback reentrant.
In the case of drr, there won't be a UAF, but the code will add the same
classifier to the list twice, which will cause memory corruption.
In addition to checking for qlen being zero, this patch checks whether the
class was already added to the active_list (cl_is_active) before adding
to the list to cover for the reentrant case.
[1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/
CVSS Score
7.0
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
pds_core: remove write-after-free of client_id
A use-after-free error popped up in stress testing:
[Mon Apr 21 21:21:33 2025] BUG: KFENCE: use-after-free write in pdsc_auxbus_dev_del+0xef/0x160 [pds_core]
[Mon Apr 21 21:21:33 2025] Use-after-free write at 0x000000007013ecd1 (in kfence-#47):
[Mon Apr 21 21:21:33 2025] pdsc_auxbus_dev_del+0xef/0x160 [pds_core]
[Mon Apr 21 21:21:33 2025] pdsc_remove+0xc0/0x1b0 [pds_core]
[Mon Apr 21 21:21:33 2025] pci_device_remove+0x24/0x70
[Mon Apr 21 21:21:33 2025] device_release_driver_internal+0x11f/0x180
[Mon Apr 21 21:21:33 2025] driver_detach+0x45/0x80
[Mon Apr 21 21:21:33 2025] bus_remove_driver+0x83/0xe0
[Mon Apr 21 21:21:33 2025] pci_unregister_driver+0x1a/0x80
The actual device uninit usually happens on a separate thread
scheduled after this code runs, but there is no guarantee of order
of thread execution, so this could be a problem. There's no
actual need to clear the client_id at this point, so simply
remove the offending code.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
net: ethernet: mtk-star-emac: fix spinlock recursion issues on rx/tx poll
Use spin_lock_irqsave and spin_unlock_irqrestore instead of spin_lock
and spin_unlock in mtk_star_emac driver to avoid spinlock recursion
occurrence that can happen when enabling the DMA interrupts again in
rx/tx poll.
```
BUG: spinlock recursion on CPU#0, swapper/0/0
lock: 0xffff00000db9cf20, .magic: dead4ead, .owner: swapper/0/0,
.owner_cpu: 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted
6.15.0-rc2-next-20250417-00001-gf6a27738686c-dirty #28 PREEMPT
Hardware name: MediaTek MT8365 Open Platform EVK (DT)
Call trace:
show_stack+0x18/0x24 (C)
dump_stack_lvl+0x60/0x80
dump_stack+0x18/0x24
spin_dump+0x78/0x88
do_raw_spin_lock+0x11c/0x120
_raw_spin_lock+0x20/0x2c
mtk_star_handle_irq+0xc0/0x22c [mtk_star_emac]
__handle_irq_event_percpu+0x48/0x140
handle_irq_event+0x4c/0xb0
handle_fasteoi_irq+0xa0/0x1bc
handle_irq_desc+0x34/0x58
generic_handle_domain_irq+0x1c/0x28
gic_handle_irq+0x4c/0x120
do_interrupt_handler+0x50/0x84
el1_interrupt+0x34/0x68
el1h_64_irq_handler+0x18/0x24
el1h_64_irq+0x6c/0x70
regmap_mmio_read32le+0xc/0x20 (P)
_regmap_bus_reg_read+0x6c/0xac
_regmap_read+0x60/0xdc
regmap_read+0x4c/0x80
mtk_star_rx_poll+0x2f4/0x39c [mtk_star_emac]
__napi_poll+0x38/0x188
net_rx_action+0x164/0x2c0
handle_softirqs+0x100/0x244
__do_softirq+0x14/0x20
____do_softirq+0x10/0x20
call_on_irq_stack+0x24/0x64
do_softirq_own_stack+0x1c/0x40
__irq_exit_rcu+0xd4/0x10c
irq_exit_rcu+0x10/0x1c
el1_interrupt+0x38/0x68
el1h_64_irq_handler+0x18/0x24
el1h_64_irq+0x6c/0x70
cpuidle_enter_state+0xac/0x320 (P)
cpuidle_enter+0x38/0x50
do_idle+0x1e4/0x260
cpu_startup_entry+0x34/0x3c
rest_init+0xdc/0xe0
console_on_rootfs+0x0/0x6c
__primary_switched+0x88/0x90
```
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: btusb: avoid NULL pointer dereference in skb_dequeue()
A NULL pointer dereference can occur in skb_dequeue() when processing a
QCA firmware crash dump on WCN7851 (0489:e0f3).
[ 93.672166] Bluetooth: hci0: ACL memdump size(589824)
[ 93.672475] BUG: kernel NULL pointer dereference, address: 0000000000000008
[ 93.672517] Workqueue: hci0 hci_devcd_rx [bluetooth]
[ 93.672598] RIP: 0010:skb_dequeue+0x50/0x80
The issue stems from handle_dump_pkt_qca() returning 0 even when a dump
packet is successfully processed. This is because it incorrectly
forwards the return value of hci_devcd_init() (which returns 0 on
success). As a result, the caller (btusb_recv_acl_qca() or
btusb_recv_evt_qca()) assumes the packet was not handled and passes it
to hci_recv_frame(), leading to premature kfree() of the skb.
Later, hci_devcd_rx() attempts to dequeue the same skb from the dump
queue, resulting in a NULL pointer dereference.
Fix this by:
1. Making handle_dump_pkt_qca() return 0 on success and negative errno
on failure, consistent with kernel conventions.
2. Splitting dump packet detection into separate functions for ACL
and event packets for better structure and readability.
This ensures dump packets are properly identified and consumed, avoiding
double handling and preventing NULL pointer access.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
xsk: Fix race condition in AF_XDP generic RX path
Move rx_lock from xsk_socket to xsk_buff_pool.
Fix synchronization for shared umem mode in
generic RX path where multiple sockets share
single xsk_buff_pool.
RX queue is exclusive to xsk_socket, while FILL
queue can be shared between multiple sockets.
This could result in race condition where two
CPU cores access RX path of two different sockets
sharing the same umem.
Protect both queues by acquiring spinlock in shared
xsk_buff_pool.
Lock contention may be minimized in the future by some
per-thread FQ buffering.
It's safe and necessary to move spin_lock_bh(rx_lock)
after xsk_rcv_check():
* xs->pool and spinlock_init is synchronized by
xsk_bind() -> xsk_is_bound() memory barriers.
* xsk_rcv_check() may return true at the moment
of xsk_release() or xsk_unbind_dev(),
however this will not cause any data races or
race conditions. xsk_unbind_dev() removes xdp
socket from all maps and waits for completion
of all outstanding rx operations. Packets in
RX path will either complete safely or drop.
CVSS Score
4.7
EPSS Score
0.0
Published
2025-05-20
In the Linux kernel, the following vulnerability has been resolved:
vxlan: vnifilter: Fix unlocked deletion of default FDB entry
When a VNI is deleted from a VXLAN device in 'vnifilter' mode, the FDB
entry associated with the default remote (assuming one was configured)
is deleted without holding the hash lock. This is wrong and will result
in a warning [1] being generated by the lockdep annotation that was
added by commit ebe642067455 ("vxlan: Create wrappers for FDB lookup").
Reproducer:
# ip link add vx0 up type vxlan dstport 4789 external vnifilter local 192.0.2.1
# bridge vni add vni 10010 remote 198.51.100.1 dev vx0
# bridge vni del vni 10010 dev vx0
Fix by acquiring the hash lock before the deletion and releasing it
afterwards. Blame the original commit that introduced the issue rather
than the one that exposed it.
[1]
WARNING: CPU: 3 PID: 392 at drivers/net/vxlan/vxlan_core.c:417 vxlan_find_mac+0x17f/0x1a0
[...]
RIP: 0010:vxlan_find_mac+0x17f/0x1a0
[...]
Call Trace:
<TASK>
__vxlan_fdb_delete+0xbe/0x560
vxlan_vni_delete_group+0x2ba/0x940
vxlan_vni_del.isra.0+0x15f/0x580
vxlan_process_vni_filter+0x38b/0x7b0
vxlan_vnifilter_process+0x3bb/0x510
rtnetlink_rcv_msg+0x2f7/0xb70
netlink_rcv_skb+0x131/0x360
netlink_unicast+0x426/0x710
netlink_sendmsg+0x75a/0xc20
__sock_sendmsg+0xc1/0x150
____sys_sendmsg+0x5aa/0x7b0
___sys_sendmsg+0xfc/0x180
__sys_sendmsg+0x121/0x1b0
do_syscall_64+0xbb/0x1d0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
CVSS Score
7.8
EPSS Score
0.0
Published
2025-05-20