In the Linux kernel, the following vulnerability has been resolved:
netfilter: nfnetlink_cthelper: fix OOB read in nfnl_cthelper_dump_table()
nfnl_cthelper_dump_table() has a 'goto restart' that jumps to a label
inside the for loop body. When the "last" helper saved in cb->args[1]
is deleted between dump rounds, every entry fails the (cur != last)
check, so cb->args[1] is never cleared. The for loop finishes with
cb->args[0] == nf_ct_helper_hsize, and the 'goto restart' jumps back
into the loop body bypassing the bounds check, causing an 8-byte
out-of-bounds read on nf_ct_helper_hash[nf_ct_helper_hsize].
The 'goto restart' block was meant to re-traverse the current bucket
when "last" is no longer found, but it was placed after the for loop
instead of inside it. Move the block into the for loop body so that
the restart only occurs while cb->args[0] is still within bounds.
BUG: KASAN: slab-out-of-bounds in nfnl_cthelper_dump_table+0x9f/0x1b0
Read of size 8 at addr ffff888104ca3000 by task poc_cthelper/131
Call Trace:
nfnl_cthelper_dump_table+0x9f/0x1b0
netlink_dump+0x333/0x880
netlink_recvmsg+0x3e2/0x4b0
sock_recvmsg+0xde/0xf0
__sys_recvfrom+0x150/0x200
__x64_sys_recvfrom+0x76/0x90
do_syscall_64+0xc3/0x6e0
Allocated by task 1:
__kvmalloc_node_noprof+0x21b/0x700
nf_ct_alloc_hashtable+0x65/0xd0
nf_conntrack_helper_init+0x21/0x60
nf_conntrack_init_start+0x18d/0x300
nf_conntrack_standalone_init+0x12/0xc0
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nfnetlink_queue: fix entry leak in bridge verdict error path
nfqnl_recv_verdict() calls find_dequeue_entry() to remove the queue
entry from the queue data structures, taking ownership of the entry.
For PF_BRIDGE packets, it then calls nfqa_parse_bridge() to parse VLAN
attributes. If nfqa_parse_bridge() returns an error (e.g. NFQA_VLAN
present but NFQA_VLAN_TCI missing), the function returns immediately
without freeing the dequeued entry or its sk_buff.
This leaks the nf_queue_entry, its associated sk_buff, and all held
references (net_device refcounts, struct net refcount). Repeated
triggering exhausts kernel memory.
Fix this by dropping the entry via nfqnl_reinject() with NF_DROP verdict
on the error path, consistent with other error handling in this file.
In the Linux kernel, the following vulnerability has been resolved:
netfilter: x_tables: guard option walkers against 1-byte tail reads
When the last byte of options is a non-single-byte option kind, walkers
that advance with i += op[i + 1] ? : 1 can read op[i + 1] past the end
of the option area.
Add an explicit i == optlen - 1 check before dereferencing op[i + 1]
in xt_tcpudp and xt_dccp option walkers.
In the Linux kernel, the following vulnerability has been resolved:
ALSA: pcm: fix use-after-free on linked stream runtime in snd_pcm_drain()
In the drain loop, the local variable 'runtime' is reassigned to a
linked stream's runtime (runtime = s->runtime at line 2157). After
releasing the stream lock at line 2169, the code accesses
runtime->no_period_wakeup, runtime->rate, and runtime->buffer_size
(lines 2170-2178) — all referencing the linked stream's runtime without
any lock or refcount protecting its lifetime.
A concurrent close() on the linked stream's fd triggers
snd_pcm_release_substream() → snd_pcm_drop() → pcm_release_private()
→ snd_pcm_unlink() → snd_pcm_detach_substream() → kfree(runtime).
No synchronization prevents kfree(runtime) from completing while the
drain path dereferences the stale pointer.
Fix by caching the needed runtime fields (no_period_wakeup, rate,
buffer_size) into local variables while still holding the stream lock,
and using the cached values after the lock is released.
In the Linux kernel, the following vulnerability has been resolved:
sched_ext: Remove redundant css_put() in scx_cgroup_init()
The iterator css_for_each_descendant_pre() walks the cgroup hierarchy
under cgroup_lock(). It does not increment the reference counts on
yielded css structs.
According to the cgroup documentation, css_put() should only be used
to release a reference obtained via css_get() or css_tryget_online().
Since the iterator does not use either of these to acquire a reference,
calling css_put() in the error path of scx_cgroup_init() causes a
refcount underflow.
Remove the unbalanced css_put() to prevent a potential Use-After-Free
(UAF) vulnerability.
In the Linux kernel, the following vulnerability has been resolved:
cgroup: fix race between task migration and iteration
When a task is migrated out of a css_set, cgroup_migrate_add_task()
first moves it from cset->tasks to cset->mg_tasks via:
list_move_tail(&task->cg_list, &cset->mg_tasks);
If a css_task_iter currently has it->task_pos pointing to this task,
css_set_move_task() calls css_task_iter_skip() to keep the iterator
valid. However, since the task has already been moved to ->mg_tasks,
the iterator is advanced relative to the mg_tasks list instead of the
original tasks list. As a result, remaining tasks on cset->tasks, as
well as tasks queued on cset->mg_tasks, can be skipped by iteration.
Fix this by calling css_set_skip_task_iters() before unlinking
task->cg_list from cset->tasks. This advances all active iterators to
the next task on cset->tasks, so iteration continues correctly even
when a task is concurrently being migrated.
This race is hard to hit in practice without instrumentation, but it
can be reproduced by artificially slowing down cgroup_procs_show().
For example, on an Android device a temporary
/sys/kernel/cgroup/cgroup_test knob can be added to inject a delay
into cgroup_procs_show(), and then:
1) Spawn three long-running tasks (PIDs 101, 102, 103).
2) Create a test cgroup and move the tasks into it.
3) Enable a large delay via /sys/kernel/cgroup/cgroup_test.
4) In one shell, read cgroup.procs from the test cgroup.
5) Within the delay window, in another shell migrate PID 102 by
writing it to a different cgroup.procs file.
Under this setup, cgroup.procs can intermittently show only PID 101
while skipping PID 103. Once the migration completes, reading the
file again shows all tasks as expected.
Note that this change does not allow removing the existing
css_set_skip_task_iters() call in css_set_move_task(). The new call
in cgroup_migrate_add_task() only handles iterators that are racing
with migration while the task is still on cset->tasks. Iterators may
also start after the task has been moved to cset->mg_tasks. If we
dropped css_set_skip_task_iters() from css_set_move_task(), such
iterators could keep task_pos pointing to a migrating task, causing
css_task_iter_advance() to malfunction on the destination css_set,
up to and including crashes or infinite loops.
The race window between migration and iteration is very small, and
css_task_iter is not on a hot path. In the worst case, when an
iterator is positioned on the first thread of the migrating process,
cgroup_migrate_add_task() may have to skip multiple tasks via
css_set_skip_task_iters(). However, this only happens when migration
and iteration actually race, so the performance impact is negligible
compared to the correctness fix provided here.
In the Linux kernel, the following vulnerability has been resolved:
net/mana: Null service_wq on setup error to prevent double destroy
In mana_gd_setup() error path, set gc->service_wq to NULL after
destroy_workqueue() to match the cleanup in mana_gd_cleanup().
This prevents a use-after-free if the workqueue pointer is checked
after a failed setup.
In the Linux kernel, the following vulnerability has been resolved:
net: bonding: Fix nd_tbl NULL dereference when IPv6 is disabled
When booting with the 'ipv6.disable=1' parameter, the nd_tbl is never
initialized because inet6_init() exits before ndisc_init() is called
which initializes it. If bonding ARP/NS validation is enabled, an IPv6
NS/NA packet received on a slave can reach bond_validate_na(), which
calls bond_has_this_ip6(). That path calls ipv6_chk_addr() and can
crash in __ipv6_chk_addr_and_flags().
BUG: kernel NULL pointer dereference, address: 00000000000005d8
Oops: Oops: 0000 [#1] SMP NOPTI
RIP: 0010:__ipv6_chk_addr_and_flags+0x69/0x170
Call Trace:
<IRQ>
ipv6_chk_addr+0x1f/0x30
bond_validate_na+0x12e/0x1d0 [bonding]
? __pfx_bond_handle_frame+0x10/0x10 [bonding]
bond_rcv_validate+0x1a0/0x450 [bonding]
bond_handle_frame+0x5e/0x290 [bonding]
? srso_alias_return_thunk+0x5/0xfbef5
__netif_receive_skb_core.constprop.0+0x3e8/0xe50
? srso_alias_return_thunk+0x5/0xfbef5
? update_cfs_rq_load_avg+0x1a/0x240
? srso_alias_return_thunk+0x5/0xfbef5
? __enqueue_entity+0x5e/0x240
__netif_receive_skb_one_core+0x39/0xa0
process_backlog+0x9c/0x150
__napi_poll+0x30/0x200
? srso_alias_return_thunk+0x5/0xfbef5
net_rx_action+0x338/0x3b0
handle_softirqs+0xc9/0x2a0
do_softirq+0x42/0x60
</IRQ>
<TASK>
__local_bh_enable_ip+0x62/0x70
__dev_queue_xmit+0x2d3/0x1000
? srso_alias_return_thunk+0x5/0xfbef5
? srso_alias_return_thunk+0x5/0xfbef5
? packet_parse_headers+0x10a/0x1a0
packet_sendmsg+0x10da/0x1700
? kick_pool+0x5f/0x140
? srso_alias_return_thunk+0x5/0xfbef5
? __queue_work+0x12d/0x4f0
__sys_sendto+0x1f3/0x220
__x64_sys_sendto+0x24/0x30
do_syscall_64+0x101/0xf80
? exc_page_fault+0x6e/0x170
? srso_alias_return_thunk+0x5/0xfbef5
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
Fix this by checking ipv6_mod_enabled() before dispatching IPv6 packets to
bond_na_rcv(). If IPv6 is disabled, return early from bond_rcv_validate()
and avoid the path to ipv6_chk_addr().