| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
smb: client: Fix use-after-free in cifs_fill_dirent
There is a race condition in the readdir concurrency process, which may
access the rsp buffer after it has been released, triggering the
following KASAN warning.
==================================================================
BUG: KASAN: slab-use-after-free in cifs_fill_dirent+0xb03/0xb60 [cifs]
Read of size 4 at addr ffff8880099b819c by task a.out/342975
CPU: 2 UID: 0 PID: 342975 Comm: a.out Not tainted 6.15.0-rc6+ #240 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x53/0x70
print_report+0xce/0x640
kasan_report+0xb8/0xf0
cifs_fill_dirent+0xb03/0xb60 [cifs]
cifs_readdir+0x12cb/0x3190 [cifs]
iterate_dir+0x1a1/0x520
__x64_sys_getdents+0x134/0x220
do_syscall_64+0x4b/0x110
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f996f64b9f9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89
f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01
f0 ff ff 0d f7 c3 0c 00 f7 d8 64 89 8
RSP: 002b:00007f996f53de78 EFLAGS: 00000207 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00007f996f53ecdc RCX: 00007f996f64b9f9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f996f53dea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000207 R12: ffffffffffffff88
R13: 0000000000000000 R14: 00007ffc8cd9a500 R15: 00007f996f51e000
</TASK>
Allocated by task 408:
kasan_save_stack+0x20/0x40
kasan_save_track+0x14/0x30
__kasan_slab_alloc+0x6e/0x70
kmem_cache_alloc_noprof+0x117/0x3d0
mempool_alloc_noprof+0xf2/0x2c0
cifs_buf_get+0x36/0x80 [cifs]
allocate_buffers+0x1d2/0x330 [cifs]
cifs_demultiplex_thread+0x22b/0x2690 [cifs]
kthread+0x394/0x720
ret_from_fork+0x34/0x70
ret_from_fork_asm+0x1a/0x30
Freed by task 342979:
kasan_save_stack+0x20/0x40
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3b/0x60
__kasan_slab_free+0x37/0x50
kmem_cache_free+0x2b8/0x500
cifs_buf_release+0x3c/0x70 [cifs]
cifs_readdir+0x1c97/0x3190 [cifs]
iterate_dir+0x1a1/0x520
__x64_sys_getdents64+0x134/0x220
do_syscall_64+0x4b/0x110
entry_SYSCALL_64_after_hwframe+0x76/0x7e
The buggy address belongs to the object at ffff8880099b8000
which belongs to the cache cifs_request of size 16588
The buggy address is located 412 bytes inside of
freed 16588-byte region [ffff8880099b8000, ffff8880099bc0cc)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x99b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff888001e03400 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000010001 00000000f5000000 0000000000000000
head: 0080000000000040 ffff888001e03400 0000000000000000 dead000000000001
head: 0000000000000000 0000000000010001 00000000f5000000 0000000000000000
head: 0080000000000003 ffffea0000266e01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8880099b8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880099b8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880099b8180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880099b8200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880099b8280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
POC is available in the link [1].
The problem triggering process is as follows:
Process 1 Process 2
-----------------------------------
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
nvmet-tcp: don't restore null sk_state_change
queue->state_change is set as part of nvmet_tcp_set_queue_sock(), but if
the TCP connection isn't established when nvmet_tcp_set_queue_sock() is
called then queue->state_change isn't set and sock->sk->sk_state_change
isn't replaced.
As such we don't need to restore sock->sk->sk_state_change if
queue->state_change is NULL.
This avoids NULL pointer dereferences such as this:
[ 286.462026][ C0] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 286.462814][ C0] #PF: supervisor instruction fetch in kernel mode
[ 286.463796][ C0] #PF: error_code(0x0010) - not-present page
[ 286.464392][ C0] PGD 8000000140620067 P4D 8000000140620067 PUD 114201067 PMD 0
[ 286.465086][ C0] Oops: Oops: 0010 [#1] SMP KASAN PTI
[ 286.465559][ C0] CPU: 0 UID: 0 PID: 1628 Comm: nvme Not tainted 6.15.0-rc2+ #11 PREEMPT(voluntary)
[ 286.466393][ C0] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014
[ 286.467147][ C0] RIP: 0010:0x0
[ 286.467420][ C0] Code: Unable to access opcode bytes at 0xffffffffffffffd6.
[ 286.467977][ C0] RSP: 0018:ffff8883ae008580 EFLAGS: 00010246
[ 286.468425][ C0] RAX: 0000000000000000 RBX: ffff88813fd34100 RCX: ffffffffa386cc43
[ 286.469019][ C0] RDX: 1ffff11027fa68b6 RSI: 0000000000000008 RDI: ffff88813fd34100
[ 286.469545][ C0] RBP: ffff88813fd34160 R08: 0000000000000000 R09: ffffed1027fa682c
[ 286.470072][ C0] R10: ffff88813fd34167 R11: 0000000000000000 R12: ffff88813fd344c3
[ 286.470585][ C0] R13: ffff88813fd34112 R14: ffff88813fd34aec R15: ffff888132cdd268
[ 286.471070][ C0] FS: 00007fe3c04c7d80(0000) GS:ffff88840743f000(0000) knlGS:0000000000000000
[ 286.471644][ C0] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 286.472543][ C0] CR2: ffffffffffffffd6 CR3: 000000012daca000 CR4: 00000000000006f0
[ 286.473500][ C0] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 286.474467][ C0] DR3: 0000000000000000 DR6: 00000000ffff07f0 DR7: 0000000000000400
[ 286.475453][ C0] Call Trace:
[ 286.476102][ C0] <IRQ>
[ 286.476719][ C0] tcp_fin+0x2bb/0x440
[ 286.477429][ C0] tcp_data_queue+0x190f/0x4e60
[ 286.478174][ C0] ? __build_skb_around+0x234/0x330
[ 286.478940][ C0] ? rcu_is_watching+0x11/0xb0
[ 286.479659][ C0] ? __pfx_tcp_data_queue+0x10/0x10
[ 286.480431][ C0] ? tcp_try_undo_loss+0x640/0x6c0
[ 286.481196][ C0] ? seqcount_lockdep_reader_access.constprop.0+0x82/0x90
[ 286.482046][ C0] ? kvm_clock_get_cycles+0x14/0x30
[ 286.482769][ C0] ? ktime_get+0x66/0x150
[ 286.483433][ C0] ? rcu_is_watching+0x11/0xb0
[ 286.484146][ C0] tcp_rcv_established+0x6e4/0x2050
[ 286.484857][ C0] ? rcu_is_watching+0x11/0xb0
[ 286.485523][ C0] ? ipv4_dst_check+0x160/0x2b0
[ 286.486203][ C0] ? __pfx_tcp_rcv_established+0x10/0x10
[ 286.486917][ C0] ? lock_release+0x217/0x2c0
[ 286.487595][ C0] tcp_v4_do_rcv+0x4d6/0x9b0
[ 286.488279][ C0] tcp_v4_rcv+0x2af8/0x3e30
[ 286.488904][ C0] ? raw_local_deliver+0x51b/0xad0
[ 286.489551][ C0] ? rcu_is_watching+0x11/0xb0
[ 286.490198][ C0] ? __pfx_tcp_v4_rcv+0x10/0x10
[ 286.490813][ C0] ? __pfx_raw_local_deliver+0x10/0x10
[ 286.491487][ C0] ? __pfx_nf_confirm+0x10/0x10 [nf_conntrack]
[ 286.492275][ C0] ? rcu_is_watching+0x11/0xb0
[ 286.492900][ C0] ip_protocol_deliver_rcu+0x8f/0x370
[ 286.493579][ C0] ip_local_deliver_finish+0x297/0x420
[ 286.494268][ C0] ip_local_deliver+0x168/0x430
[ 286.494867][ C0] ? __pfx_ip_local_deliver+0x10/0x10
[ 286.495498][ C0] ? __pfx_ip_local_deliver_finish+0x10/0x10
[ 286.496204][ C0] ? ip_rcv_finish_core+0x19a/0x1f20
[ 286.496806][ C0] ? lock_release+0x217/0x2c0
[ 286.497414][ C0] ip_rcv+0x455/0x6e0
[ 286.497945][ C0] ? __pfx_ip_rcv+0x10/0x10
[
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
NFS/localio: Fix a race in nfs_local_open_fh()
Once the clp->cl_uuid.lock has been dropped, another CPU could come in
and free the struct nfsd_file that was just added. To prevent that from
happening, take the RCU read lock before dropping the spin lock. |
| In the Linux kernel, the following vulnerability has been resolved:
net/tls: fix kernel panic when alloc_page failed
We cannot set frag_list to NULL pointer when alloc_page failed.
It will be used in tls_strp_check_queue_ok when the next time
tls_strp_read_sock is called.
This is because we don't reset full_len in tls_strp_flush_anchor_copy()
so the recv path will try to continue handling the partial record
on the next call but we dettached the rcvq from the frag list.
Alternative fix would be to reset full_len.
Unable to handle kernel NULL pointer dereference
at virtual address 0000000000000028
Call trace:
tls_strp_check_rcv+0x128/0x27c
tls_strp_data_ready+0x34/0x44
tls_data_ready+0x3c/0x1f0
tcp_data_ready+0x9c/0xe4
tcp_data_queue+0xf6c/0x12d0
tcp_rcv_established+0x52c/0x798 |
| In the Linux kernel, the following vulnerability has been resolved:
HID: bpf: abort dispatch if device destroyed
The current HID bpf implementation assumes no output report/request will
go through it after hid_bpf_destroy_device() has been called. This leads
to a bug that unplugging certain types of HID devices causes a cleaned-
up SRCU to be accessed. The bug was previously a hidden failure until a
recent x86 percpu change [1] made it access not-present pages.
The bug will be triggered if the conditions below are met:
A) a device under the driver has some LEDs on
B) hid_ll_driver->request() is uninplemented (e.g., logitech-djreceiver)
If condition A is met, hidinput_led_worker() is always scheduled *after*
hid_bpf_destroy_device().
hid_destroy_device
` hid_bpf_destroy_device
` cleanup_srcu_struct(&hdev->bpf.srcu)
` hid_remove_device
` ...
` led_classdev_unregister
` led_trigger_set(led_cdev, NULL)
` led_set_brightness(led_cdev, LED_OFF)
` ...
` input_inject_event
` input_event_dispose
` hidinput_input_event
` schedule_work(&hid->led_work) [hidinput_led_worker]
This is fine when condition B is not met, where hidinput_led_worker()
calls hid_ll_driver->request(). This is the case for most HID drivers,
which implement it or use the generic one from usbhid. The driver itself
or an underlying driver will then abort processing the request.
Otherwise, hidinput_led_worker() tries hid_hw_output_report() and leads
to the bug.
hidinput_led_worker
` hid_hw_output_report
` dispatch_hid_bpf_output_report
` srcu_read_lock(&hdev->bpf.srcu)
` srcu_read_unlock(&hdev->bpf.srcu, idx)
The bug has existed since the introduction [2] of
dispatch_hid_bpf_output_report(). However, the same bug also exists in
dispatch_hid_bpf_raw_requests(), and I've reproduced (no visible effect
because of the lack of [1], but confirmed bpf.destroyed == 1) the bug
against the commit (i.e., the Fixes:) introducing the function. This is
because hidinput_led_worker() falls back to hid_hw_raw_request() when
hid_ll_driver->output_report() is uninplemented (e.g., logitech-
djreceiver).
hidinput_led_worker
` hid_hw_output_report: -ENOSYS
` hid_hw_raw_request
` dispatch_hid_bpf_raw_requests
` srcu_read_lock(&hdev->bpf.srcu)
` srcu_read_unlock(&hdev->bpf.srcu, idx)
Fix the issue by returning early in the two mentioned functions if
hid_bpf has been marked as destroyed. Though
dispatch_hid_bpf_device_event() handles input events, and there is no
evidence that it may be called after the destruction, the same check, as
a safety net, is also added to it to maintain the consistency among all
dispatch functions.
The impact of the bug on other architectures is unclear. Even if it acts
as a hidden failure, this is still dangerous because it corrupts
whatever is on the address calculated by SRCU. Thus, CC'ing the stable
list.
[1]: commit 9d7de2aa8b41 ("x86/percpu/64: Use relative percpu offsets")
[2]: commit 9286675a2aed ("HID: bpf: add HID-BPF hooks for
hid_hw_output_report") |
| In the Linux kernel, the following vulnerability has been resolved:
sched_ext: bpf_iter_scx_dsq_new() should always initialize iterator
BPF programs may call next() and destroy() on BPF iterators even after new()
returns an error value (e.g. bpf_for_each() macro ignores error returns from
new()). bpf_iter_scx_dsq_new() could leave the iterator in an uninitialized
state after an error return causing bpf_iter_scx_dsq_next() to dereference
garbage data. Make bpf_iter_scx_dsq_new() always clear $kit->dsq so that
next() and destroy() become noops. |
| In the Linux kernel, the following vulnerability has been resolved:
dmaengine: ti: k3-udma: Add missing locking
Recent kernels complain about a missing lock in k3-udma.c when the lock
validator is enabled:
[ 4.128073] WARNING: CPU: 0 PID: 746 at drivers/dma/ti/../virt-dma.h:169 udma_start.isra.0+0x34/0x238
[ 4.137352] CPU: 0 UID: 0 PID: 746 Comm: kworker/0:3 Not tainted 6.12.9-arm64 #28
[ 4.144867] Hardware name: pp-v12 (DT)
[ 4.148648] Workqueue: events udma_check_tx_completion
[ 4.153841] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 4.160834] pc : udma_start.isra.0+0x34/0x238
[ 4.165227] lr : udma_start.isra.0+0x30/0x238
[ 4.169618] sp : ffffffc083cabcf0
[ 4.172963] x29: ffffffc083cabcf0 x28: 0000000000000000 x27: ffffff800001b005
[ 4.180167] x26: ffffffc0812f0000 x25: 0000000000000000 x24: 0000000000000000
[ 4.187370] x23: 0000000000000001 x22: 00000000e21eabe9 x21: ffffff8000fa0670
[ 4.194571] x20: ffffff8001b6bf00 x19: ffffff8000fa0430 x18: ffffffc083b95030
[ 4.201773] x17: 0000000000000000 x16: 00000000f0000000 x15: 0000000000000048
[ 4.208976] x14: 0000000000000048 x13: 0000000000000000 x12: 0000000000000001
[ 4.216179] x11: ffffffc08151a240 x10: 0000000000003ea1 x9 : ffffffc08046ab68
[ 4.223381] x8 : ffffffc083cabac0 x7 : ffffffc081df3718 x6 : 0000000000029fc8
[ 4.230583] x5 : ffffffc0817ee6d8 x4 : 0000000000000bc0 x3 : 0000000000000000
[ 4.237784] x2 : 0000000000000000 x1 : 00000000001fffff x0 : 0000000000000000
[ 4.244986] Call trace:
[ 4.247463] udma_start.isra.0+0x34/0x238
[ 4.251509] udma_check_tx_completion+0xd0/0xdc
[ 4.256076] process_one_work+0x244/0x3fc
[ 4.260129] process_scheduled_works+0x6c/0x74
[ 4.264610] worker_thread+0x150/0x1dc
[ 4.268398] kthread+0xd8/0xe8
[ 4.271492] ret_from_fork+0x10/0x20
[ 4.275107] irq event stamp: 220
[ 4.278363] hardirqs last enabled at (219): [<ffffffc080a27c7c>] _raw_spin_unlock_irq+0x38/0x50
[ 4.287183] hardirqs last disabled at (220): [<ffffffc080a1c154>] el1_dbg+0x24/0x50
[ 4.294879] softirqs last enabled at (182): [<ffffffc080037e68>] handle_softirqs+0x1c0/0x3cc
[ 4.303437] softirqs last disabled at (177): [<ffffffc080010170>] __do_softirq+0x1c/0x28
[ 4.311559] ---[ end trace 0000000000000000 ]---
This commit adds the missing locking. |
| In the Linux kernel, the following vulnerability has been resolved:
can: bcm: add locking for bcm_op runtime updates
The CAN broadcast manager (CAN BCM) can send a sequence of CAN frames via
hrtimer. The content and also the length of the sequence can be changed
resp reduced at runtime where the 'currframe' counter is then set to zero.
Although this appeared to be a safe operation the updates of 'currframe'
can be triggered from user space and hrtimer context in bcm_can_tx().
Anderson Nascimento created a proof of concept that triggered a KASAN
slab-out-of-bounds read access which can be prevented with a spin_lock_bh.
At the rework of bcm_can_tx() the 'count' variable has been moved into
the protected section as this variable can be modified from both contexts
too. |
| In the Linux kernel, the following vulnerability has been resolved:
can: bcm: add missing rcu read protection for procfs content
When the procfs content is generated for a bcm_op which is in the process
to be removed the procfs output might show unreliable data (UAF).
As the removal of bcm_op's is already implemented with rcu handling this
patch adds the missing rcu_read_lock() and makes sure the list entries
are properly removed under rcu protection. |
| In the Linux kernel, the following vulnerability has been resolved:
io_uring/fdinfo: grab ctx->uring_lock around io_uring_show_fdinfo()
Not everything requires locking in there, which is why the 'has_lock'
variable exists. But enough does that it's a bit unwieldy to manage.
Wrap the whole thing in a ->uring_lock trylock, and just return
with no output if we fail to grab it. The existing trylock() will
already have greatly diminished utility/output for the failure case.
This fixes an issue with reading the SQE fields, if the ring is being
actively resized at the same time. |
| In the Linux kernel, the following vulnerability has been resolved:
net_sched: hfsc: Address reentrant enqueue adding class to eltree twice
Savino says:
"We are writing to report that this recent patch
(141d34391abbb315d68556b7c67ad97885407547) [1]
can be bypassed, and a UAF can still occur when HFSC is utilized with
NETEM.
The patch only checks the cl->cl_nactive field to determine whether
it is the first insertion or not [2], but this field is only
incremented by init_vf [3].
By using HFSC_RSC (which uses init_ed) [4], it is possible to bypass the
check and insert the class twice in the eltree.
Under normal conditions, this would lead to an infinite loop in
hfsc_dequeue for the reasons we already explained in this report [5].
However, if TBF is added as root qdisc and it is configured with a
very low rate,
it can be utilized to prevent packets from being dequeued.
This behavior can be exploited to perform subsequent insertions in the
HFSC eltree and cause a UAF."
To fix both the UAF and the infinite loop, with netem as an hfsc child,
check explicitly in hfsc_enqueue whether the class is already in the eltree
whenever the HFSC_RSC flag is set.
[1] https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=141d34391abbb315d68556b7c67ad97885407547
[2] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L1572
[3] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L677
[4] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L1574
[5] https://lore.kernel.org/netdev/8DuRWwfqjoRDLDmBMlIfbrsZg9Gx50DHJc1ilxsEBNe2D6NMoigR_eIRIG0LOjMc3r10nUUZtArXx4oZBIdUfZQrwjcQhdinnMis_0G7VEk=@willsroot.io/T/#u |
| In the Linux kernel, the following vulnerability has been resolved:
openvswitch: Fix unsafe attribute parsing in output_userspace()
This patch replaces the manual Netlink attribute iteration in
output_userspace() with nla_for_each_nested(), which ensures that only
well-formed attributes are processed. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: ipset: fix region locking in hash types
Region locking introduced in v5.6-rc4 contained three macros to handle
the region locks: ahash_bucket_start(), ahash_bucket_end() which gave
back the start and end hash bucket values belonging to a given region
lock and ahash_region() which should give back the region lock belonging
to a given hash bucket. The latter was incorrect which can lead to a
race condition between the garbage collector and adding new elements
when a hash type of set is defined with timeouts. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Fix uninitialized memcache pointer in user_mem_abort()
Commit fce886a60207 ("KVM: arm64: Plumb the pKVM MMU in KVM") made the
initialization of the local memcache variable in user_mem_abort()
conditional, leaving a codepath where it is used uninitialized via
kvm_pgtable_stage2_map().
This can fail on any path that requires a stage-2 allocation
without transition via a permission fault or dirty logging.
Fix this by making sure that memcache is always valid. |
| In the Linux kernel, the following vulnerability has been resolved:
fix a couple of races in MNT_TREE_BENEATH handling by do_move_mount()
Normally do_lock_mount(path, _) is locking a mountpoint pinned by
*path and at the time when matching unlock_mount() unlocks that
location it is still pinned by the same thing.
Unfortunately, for 'beneath' case it's no longer that simple -
the object being locked is not the one *path points to. It's the
mountpoint of path->mnt. The thing is, without sufficient locking
->mnt_parent may change under us and none of the locks are held
at that point. The rules are
* mount_lock stabilizes m->mnt_parent for any mount m.
* namespace_sem stabilizes m->mnt_parent, provided that
m is mounted.
* if either of the above holds and refcount of m is positive,
we are guaranteed the same for refcount of m->mnt_parent.
namespace_sem nests inside inode_lock(), so do_lock_mount() has
to take inode_lock() before grabbing namespace_sem. It does
recheck that path->mnt is still mounted in the same place after
getting namespace_sem, and it does take care to pin the dentry.
It is needed, since otherwise we might end up with racing mount --move
(or umount) happening while we were getting locks; in that case
dentry would no longer be a mountpoint and could've been evicted
on memory pressure along with its inode - not something you want
when grabbing lock on that inode.
However, pinning a dentry is not enough - the matching mount is
also pinned only by the fact that path->mnt is mounted on top it
and at that point we are not holding any locks whatsoever, so
the same kind of races could end up with all references to
that mount gone just as we are about to enter inode_lock().
If that happens, we are left with filesystem being shut down while
we are holding a dentry reference on it; results are not pretty.
What we need to do is grab both dentry and mount at the same time;
that makes inode_lock() safe *and* avoids the problem with fs getting
shut down under us. After taking namespace_sem we verify that
path->mnt is still mounted (which stabilizes its ->mnt_parent) and
check that it's still mounted at the same place. From that point
on to the matching namespace_unlock() we are guaranteed that
mount/dentry pair we'd grabbed are also pinned by being the mountpoint
of path->mnt, so we can quietly drop both the dentry reference (as
the current code does) and mnt one - it's OK to do under namespace_sem,
since we are not dropping the final refs.
That solves the problem on do_lock_mount() side; unlock_mount()
also has one, since dentry is guaranteed to stay pinned only until
the namespace_unlock(). That's easy to fix - just have inode_unlock()
done earlier, while it's still pinned by mp->m_dentry. |
| In the Linux kernel, the following vulnerability has been resolved:
crypto: ecdsa - Harden against integer overflows in DIV_ROUND_UP()
Herbert notes that DIV_ROUND_UP() may overflow unnecessarily if an ecdsa
implementation's ->key_size() callback returns an unusually large value.
Herbert instead suggests (for a division by 8):
X / 8 + !!(X & 7)
Based on this formula, introduce a generic DIV_ROUND_UP_POW2() macro and
use it in lieu of DIV_ROUND_UP() for ->key_size() return values.
Additionally, use the macro in ecc_digits_from_bytes(), whose "nbytes"
parameter is a ->key_size() return value in some instances, or a
user-specified ASN.1 length in the case of ecdsa_get_signature_rs(). |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: ufs: exynos: Disable iocc if dma-coherent property isn't set
If dma-coherent property isn't set then descriptors are non-cacheable
and the iocc shareability bits should be disabled. Without this UFS can
end up in an incompatible configuration and suffer from random cache
related stability issues. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: fix out-of-bounds access during multi-link element defragmentation
Currently during the multi-link element defragmentation process, the
multi-link element length added to the total IEs length when calculating
the length of remaining IEs after the multi-link element in
cfg80211_defrag_mle(). This could lead to out-of-bounds access if the
multi-link element or its corresponding fragment elements are the last
elements in the IEs buffer.
To address this issue, correctly calculate the remaining IEs length by
deducting the multi-link element end offset from total IEs end offset. |
| In the Linux kernel, the following vulnerability has been resolved:
x86/mm: Eliminate window where TLB flushes may be inadvertently skipped
tl;dr: There is a window in the mm switching code where the new CR3 is
set and the CPU should be getting TLB flushes for the new mm. But
should_flush_tlb() has a bug and suppresses the flush. Fix it by
widening the window where should_flush_tlb() sends an IPI.
Long Version:
=== History ===
There were a few things leading up to this.
First, updating mm_cpumask() was observed to be too expensive, so it was
made lazier. But being lazy caused too many unnecessary IPIs to CPUs
due to the now-lazy mm_cpumask(). So code was added to cull
mm_cpumask() periodically[2]. But that culling was a bit too aggressive
and skipped sending TLB flushes to CPUs that need them. So here we are
again.
=== Problem ===
The too-aggressive code in should_flush_tlb() strikes in this window:
// Turn on IPIs for this CPU/mm combination, but only
// if should_flush_tlb() agrees:
cpumask_set_cpu(cpu, mm_cpumask(next));
next_tlb_gen = atomic64_read(&next->context.tlb_gen);
choose_new_asid(next, next_tlb_gen, &new_asid, &need_flush);
load_new_mm_cr3(need_flush);
// ^ After 'need_flush' is set to false, IPIs *MUST*
// be sent to this CPU and not be ignored.
this_cpu_write(cpu_tlbstate.loaded_mm, next);
// ^ Not until this point does should_flush_tlb()
// become true!
should_flush_tlb() will suppress TLB flushes between load_new_mm_cr3()
and writing to 'loaded_mm', which is a window where they should not be
suppressed. Whoops.
=== Solution ===
Thankfully, the fuzzy "just about to write CR3" window is already marked
with loaded_mm==LOADED_MM_SWITCHING. Simply checking for that state in
should_flush_tlb() is sufficient to ensure that the CPU is targeted with
an IPI.
This will cause more TLB flush IPIs. But the window is relatively small
and I do not expect this to cause any kind of measurable performance
impact.
Update the comment where LOADED_MM_SWITCHING is written since it grew
yet another user.
Peter Z also raised a concern that should_flush_tlb() might not observe
'loaded_mm' and 'is_lazy' in the same order that switch_mm_irqs_off()
writes them. Add a barrier to ensure that they are observed in the
order they are written. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Scrub packet on bpf_redirect_peer
When bpf_redirect_peer is used to redirect packets to a device in
another network namespace, the skb isn't scrubbed. That can lead skb
information from one namespace to be "misused" in another namespace.
As one example, this is causing Cilium to drop traffic when using
bpf_redirect_peer to redirect packets that just went through IPsec
decryption to a container namespace. The following pwru trace shows (1)
the packet path from the host's XFRM layer to the container's XFRM
layer where it's dropped and (2) the number of active skb extensions at
each function.
NETNS MARK IFACE TUPLE FUNC
4026533547 d00 eth0 10.244.3.124:35473->10.244.2.158:53 xfrm_rcv_cb
.active_extensions = (__u8)2,
4026533547 d00 eth0 10.244.3.124:35473->10.244.2.158:53 xfrm4_rcv_cb
.active_extensions = (__u8)2,
4026533547 d00 eth0 10.244.3.124:35473->10.244.2.158:53 gro_cells_receive
.active_extensions = (__u8)2,
[...]
4026533547 0 eth0 10.244.3.124:35473->10.244.2.158:53 skb_do_redirect
.active_extensions = (__u8)2,
4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 ip_rcv
.active_extensions = (__u8)2,
4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 ip_rcv_core
.active_extensions = (__u8)2,
[...]
4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 udp_queue_rcv_one_skb
.active_extensions = (__u8)2,
4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 __xfrm_policy_check
.active_extensions = (__u8)2,
4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 __xfrm_decode_session
.active_extensions = (__u8)2,
4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 security_xfrm_decode_session
.active_extensions = (__u8)2,
4026534999 0 eth0 10.244.3.124:35473->10.244.2.158:53 kfree_skb_reason(SKB_DROP_REASON_XFRM_POLICY)
.active_extensions = (__u8)2,
In this case, there are no XFRM policies in the container's network
namespace so the drop is unexpected. When we decrypt the IPsec packet,
the XFRM state used for decryption is set in the skb extensions. This
information is preserved across the netns switch. When we reach the
XFRM policy check in the container's netns, __xfrm_policy_check drops
the packet with LINUX_MIB_XFRMINNOPOLS because a (container-side) XFRM
policy can't be found that matches the (host-side) XFRM state used for
decryption.
This patch fixes this by scrubbing the packet when using
bpf_redirect_peer, as is done on typical netns switches via veth
devices except skb->mark and skb->tstamp are not zeroed. |
