| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
RISC-V: KVM: Synchronize hrtimer callback during teardown
The non-Sstc hrtimer callback clears next_set before its final uses of
the enclosing vCPU. If teardown observes next_set as false while the
callback is still running, kvm_riscv_vcpu_timer_cancel() skips
hrtimer_cancel() and kvm_destroy_vcpus() can free the vCPU before the
callback enters kvm_riscv_vcpu_set_interrupt().
A guest can arm the timer with SBI TIME and request shutdown with SBI
legacy shutdown or SRST. A VMM that honors KVM_EXIT_SYSTEM_EVENT and
destroys the VM supplies the teardown side of the race; no post-launch
host ioctl is needed to arm or request teardown.
On upstream master 62cc90241548, generic KASAN reported:
BUG: KASAN: slab-use-after-free in do_raw_spin_lock
Write of size 4 at addr ff60000005e58898
kvm_riscv_vcpu_set_interrupt
kvm_riscv_vcpu_hrtimer_expired
__hrtimer_run_queues
hrtimer_interrupt
The object was allocated by KVM_CREATE_VCPU and freed concurrently by:
kvm_destroy_vcpus
kvm_arch_destroy_vm
kvm_destroy_vm
__fput
For deterministic validation, I added mdelay(1000) immediately after
the existing next_set = false assignment. This only widens the
existing post-clear callback window. A no-delay trace build naturally
reached the callback-after-teardown-start/before-deinit ordering in 12
of 200 runs, but 1,500 stock-kernel stress iterations did not produce a
KASAN report, so natural reproduction is timing-sensitive.
Always invoke hrtimer_cancel() for an initialized timer. Preserve the
existing -EINVAL result when the timer is no longer set, but only after
synchronizing with a running callback.
With this patch, hrtimer_cancel() blocked for the full widened callback
window before vCPU destruction. KASAN reported no error in 100
fixed-and-widened runs or 200 fix-only timing-sweep runs. |
| In the Linux kernel, the following vulnerability has been resolved:
xfs: fix cursor and pointer handling when recovering iunlink buckets
LOLLM pointed out a bug in xlog_recover_iunlink_bucket:
1. We don't null out prev_ip after releasing it, which can lead to UAF
problems if the inodegc flush call in the loop fails.
at which point I noticed even more bugs:
2. If the inodegc flush inside the loop fails, we also leak @ip.
3. We set prev_agino to agino having already advanced agino, which
results in inodes with i_prev_unlinked set to itself.
4. If we exit the bottom of the loop with prev_ip set, then prev_ip
aliases ip and we also set its i_prev_unlinked to itself.
Bugs 3 and 4 introduce loops into the unlinked list, though these loops
don't surface because we immediately flush each unlinked inode after
loading it.
Fix all of these issues. |
| In the Linux kernel, the following vulnerability has been resolved:
net/sched: act_ct: fix helper UAF due to extensions realloc
While calling the helpers, a raw pointer to the extensions area is
wired into expectations list:
-> nf_ct_helper()
-> helper->help()
-> nf_ct_expect_related_report()
-> nf_ct_expect_insert()
-> hlist_add_head_rcu(&exp->lnode, &master_help->expectations)
In case the connection is not confirmed yet, more extensions can be
added afterwards with *_ext_add() calls reallocating the extension
space and leaving the now invalid pointer in the expectations list
that is later accessed while removing the expectation.
Make sure that helpers are called at the end after all the other
extensions are already added.
Note that the helper rejection now leaves the mark and labels set,
but that's not different from how the NAT was handled before or how
the mark and the labels were handled on confirmation failure. And
there are no atomicity guarantees provided by the API anyway. |
| In the Linux kernel, the following vulnerability has been resolved:
net/sched: act_ct: avoid modifying shared unconfirmed ct entry
In a case where skb with an unconfirmed ct entry gets cloned, we may
end up processing both again but with different sets of extensions.
The series of events:
1. The first clone wants to commit and runs the helpers wiring up
the extension pointer into the expectation list.
2. Then it looses the confirmation keeping the entry unconfirmed.
3. Second clone now wants to commit labels or run NAT and adds the
new extension for that breaking the pointer in the expectation
list causing UAF on the destruction path later.
While this is possible to trigger, there should be no practical
network pipeline where we need to process both clones without
modifications in the same zone. So, let's just reset the entry in
case for some reason we got an skb with a shared one. This doesn't
affect any known use cases, but avoids any potential problems with
sharing and modification of the unconfirmed ct entry.
Unlike openvswitch module, act_ct allows for NAT without commit.
Changing that would be a uAPI break. So, act_ct needs to reset on NAT
regardless of the commit flag to avoid reallocation of the extension
space. This, however, doesn't really change the picture for sensible
networking cases as there should be no need to run the same packet
twice (before and after the clone) through conntrack without packet
header or zone changes and without commit.
The fixes tag points to the introduction of helpers, since that's the
main UAF trigger for the sharing. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv4: free inet_opt and ireq_opt after an RCU grace period
tcp_v4_syn_recv_sock() transfers ownership of ireq->ireq_opt to the
child socket (newinet->inet_opt) without copying it.
Another cpu can concurrently process a retransmitted SYN for the same
request socket, and send a SYNACK from tcp_check_req().
tcp_v4_send_synack() and inet_csk_route_req() read ireq->ireq_opt
under rcu_read_lock() only, and ip_build_and_send_pkt() and
ip_options_build() then read opt->optlen twice.
Note that the SYNACK timer itself is not an issue: it holds a
reference on its request socket, and inet_csk_reqsk_queue_drop()
calls timer_delete_sync() before the child can be freed.
Since commit 079096f103fa ("tcp/dccp: install syn_recv requests
into ehash table"), request sockets are processed without holding
the listener lock, so nothing prevents the child socket from being
freed while the SYNACK is still being built. TCP child sockets do
not have SOCK_RCU_FREE, and inet_sock_destruct() frees inet_opt
with a plain kfree(), leading to a use-after-free in
ip_options_build().
A similar issue exists with request socket migration
(net.ipv4.tcp_migrate_req=1, or a BPF_SK_REUSEPORT_SELECT_OR_MIGRATE
program). reqsk_timer_handler() clones the request socket with
inet_reqsk_clone(), so that the old request socket and its clone
share the same ireq_opt, then reqsk_migrate_reset() clears the
pointer in the old one. Another cpu holding a reference on the old
request socket can still be using these options (sending a SYNACK,
or creating a child in tcp_v4_syn_recv_sock()) when the clone is
freed, and tcp_v4_reqsk_destructor() also uses a plain kfree().
Readers already use RCU, and other paths replacing inet_opt
(do_ip_setsockopt(), cipso_v4_sock_setattr()...) already use
kfree_rcu(). Use kfree_rcu() in inet_sock_destruct() and
tcp_v4_reqsk_destructor() as well.
IPv6 is not affected by the first issue, because tcp_v6_syn_recv_sock()
duplicates the options. tcp_v6_reqsk_destructor() has the same
migration issue with ipv6_opt, which is only set by CALIPSO. This
will be addressed in a separate patch. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL
An LWT_SEG6LOCAL program can invalidate its cached SRH with
bpf_lwt_seg6_adjust_srh() and then call bpf_skb_pull_data(). The latter
may reallocate skb->head, leaving the per-CPU SRH pointer dangling.
Post-program SRH validation then writes through that pointer.
Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL programs so the verifier
rejects this unsafe helper combination. Other LWT program types continue
to expose the helper through lwt_out_func_proto(). |
| In the Linux kernel, the following vulnerability has been resolved:
veth: manage XDP program pointers during channel resize
veth_set_channels() tears down XDP resources for removed RX queues
without clearing rq->xdp_prog. If the program is then detached or
replaced, those queues keep the old pointer after bpf_prog_put().
A later channel increase can re-enable NAPI and run the freed program.
BUG: unable to handle page fault for address: ffffc90000256048
Oops: Oops: 0000 [#1] SMP KASAN NOPTI
RIP: veth_xdp_rcv_skb (include/linux/filter.h:779
include/net/xdp.h:696 drivers/net/veth.c:820)
Call Trace:
veth_xdp_rcv (drivers/net/veth.c:941)
veth_poll (drivers/net/veth.c:986)
__napi_poll (net/core/dev.c:7787)
net_rx_action (net/core/dev.c:7850 net/core/dev.c:8007)
handle_softirqs (kernel/softirq.c:645)
Kernel panic - not syncing: Fatal exception in interrupt |
| In the Linux kernel, the following vulnerability has been resolved:
tcp: fix use-after-free of retransmit_skb_hint in tcp_send_synack()
When tcp_send_synack() replaces the cloned SYN skb at the head of the
retransmit queue with a copy, it frees the original with
tcp_rtx_queue_unlink_and_free() and only repairs tp->highest_sack.
tp->retransmit_skb_hint keeps pointing at the freed
skbuff_fclone_cache object.
The dangling hint is read in tcp_verify_retransmit_hint() and used as
the root of the rbtree walk in tcp_xmit_retransmit_queue(). An
unprivileged TFO client (sendmsg(MSG_FASTOPEN)) can arm the hint with
an attacker-supplied ICMP fragmentation-needed message, after which a
simultaneous open frees the armed SYN skb:
BUG: KASAN: slab-use-after-free in tcp_mark_skb_lost (net/ipv4/tcp_input.c:1316)
Read of size 4 at addr ffff88800604d928 by task swapper/1/0
Call Trace:
tcp_mark_skb_lost (net/ipv4/tcp_input.c:1316)
tcp_simple_retransmit (net/ipv4/tcp_input.c:3158)
tcp_v4_err (net/ipv4/tcp_ipv4.c:587)
Sync the hint to the copy. |
| In the Linux kernel, the following vulnerability has been resolved:
sched/cache: Introduce task_struct->sched_cache_grp to fix UAF
Add a sched_cache_grp pointer to task_struct so that scheduler code
can access the cache group directly via the task, without going
through mm->sched_cache_grp. This decouples the scheduler's hot-path
accesses from the mm_struct.
Each task holds its own refcount on the sched_cache_group, separate
from the reference held by its mm_struct. The reference is acquired
in copy_mm() (fork) and exec_mmap() (exec), and released in exit_mm().
This fixes the use-after-free when account_mm_sched() reaches the group
through a task whose mm is being switched, as reported by Hyunwoo:
https://lore.kernel.org/lkml/apPb-Dr4nPYuHQOK@v4bel/
Convert all scheduler code in fair.c and exit.c to use
p->sched_cache_grp instead of p->mm->sched_cache_grp.
Keep the fork/exec/exit reference management out of the generic mm
paths: add sched_cache_fork(), sched_cache_fork_cleanup(),
sched_cache_exec_mmap() and sched_cache_exit_mm() in
kernel/sched/cache_sched.c (with empty stubs for !CONFIG_SCHED_CACHE),
so fs/exec.c, kernel/fork.c and kernel/exit.c each call one helper
instead of open-coding the refcounting under #ifdef. Also add
sched_cache_group_get() and task_cache_group_get(). |
| In the Linux kernel, the following vulnerability has been resolved:
sctp: check RCV_SHUTDOWN after the sendmsg connect wait
sctp_wait_for_connect() drops the socket lock while it sleeps. An
out-of-the-blue ABORT can then be processed from the socket backlog and
unlink the association. If a concurrent shutdown(fd, SHUT_RD) sets
RCV_SHUTDOWN, the waiter breaks with err == 0 before checking
asoc->base.dead. Its final sctp_association_put() can then free the
association, leaving sctp_sendmsg_to_asoc() to continue with a dangling
pointer.
Check RCV_SHUTDOWN along with the wait error in sctp_sendmsg_to_asoc()
before using the association again. The check only accesses the socket,
so it needs no additional association reference. Return the existing
-ESRCH so that sctp_sendmsg() skips freeing a new association that may
already have been destroyed.
Keep sctp_wait_for_connect() unchanged to preserve its behavior for the
connect() caller. |
| In the Linux kernel, the following vulnerability has been resolved:
net: page_pool: fix use-after-free in page_pool_recycle_ring_bulk()
With CONFIG_PAGE_POOL_STATS=y, page_pool_recycle_ring_bulk() updates
the recycle stats after dropping the producer lock. If it just recycled
the last inflight netmems of a pool being destroyed, page_pool_release()
can pass its producer-lock barrier and free the pool before
recycle_stat_add() runs.
Commit fcc680a647ba7 ("page_pool: allow mixing PPs within one bulk")
moved this stat update after the unlock. Commit 271683bb2cf32
("page_pool: Fix use-after-free in page_pool_recycle_in_ring") later
added the barrier, but only fixed page_pool_recycle_in_ring(). Move
the update back under the lock. |
| In the Linux kernel, the following vulnerability has been resolved:
nvme: fix cdev lifetime
Sashiko bot reported a potential problem for the cdev lifetime in [0]
- the code there is heavily based on the NVMe code.
Currently the NS head .open and .release file_operations methods take and
put a reference to the nvme_ns_head to ensure that this structure does not
disappear while we open fds for that cdev.
In multipath mode, when we teardown the NS head, we call nvme_cdev_del() ->
cdev_device_del() -> cdev_del(). However after cdev_del() returns, cdevs
already open will remain and their fops will still be callable. As such,
we can still reference the cdev after the nvme_ns_head reference count
drops to 0 (and is freed).
This can be shown with an application which delays between opening the cdev
and issuing the ioctl while the NS head is being torn down:
# ./ioctl_file /dev/ng1n1 &
# waiting 10 seconds ....
# ./ini_nvme_teardown.sh
[ 21.221718] nvme nvme1: Removing ctrl: NQN "nvme-test-target"
[ 21.274609] nvme nvme2: Removing ctrl: NQN "nvme-test-target"
# now going to issue ioctl ....
[ 26.549285] ==================================================================
[ 26.550841] BUG: KASAN: slab-use-after-free in cdev_put.part.0+0x3d/0x40
[ 26.552352] Read of size 8 at addr ffff88811e7fa170 by task ioctl_file/237
[ 26.553805]
[ 26.554227] CPU: 3 UID: 0 PID: 237 Comm: ioctl_file Not tainted 7.2.0-rc1-00004-g6852a10e32d4 #921 PREEMPT(lazy)
[ 26.554236] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 26.554241] Call Trace:
[ 26.554245] <TASK>
[ 26.554248] dump_stack_lvl+0x68/0xa0
[ 26.554266] print_report+0x10d/0x5d0
[ 26.554276] ? __virt_addr_valid+0x21d/0x3f0
[ 26.554287] ? cdev_put.part.0+0x3d/0x40
[ 26.554292] kasan_report+0x96/0xd0
[ 26.554300] ? cdev_put.part.0+0x3d/0x40
[ 26.554307] cdev_put.part.0+0x3d/0x40
[ 26.554313] __fput+0x7bc/0xa70
[ 26.554322] fput_close_sync+0xd8/0x190
[ 26.554328] ? __pfx_fput_close_sync+0x10/0x10
[ 26.554337] __x64_sys_close+0x79/0xd0
[ 26.554344] do_syscall_64+0x117/0x6b0
[ 26.554351] entry_SYSCALL_64_after_hwframe+0x77/0x7f
[ 26.554358] RIP: 0033:0x7f938c067727
[ 26.554364] Code: 48 89 fa 4c 89 df e8 28 ad 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5bf
[ 26.554369] RSP: 002b:00007fff49f05980 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
[ 26.554376] RAX: ffffffffffffffda RBX: 00007f938bfd7780 RCX: 00007f938c067727
[ 26.554380] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
[ 26.554383] RBP: 00007fff49f05a10 R08: 0000000000000000 R09: 0000000000000000
[ 26.554386] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
[ 26.554389] R13: 00007fff49f05b40 R14: 00007f938c207000 R15: 000055c148471d78
[ 26.554397] </TASK>
[ 26.554399]
[ 26.575612] Allocated by task 100:
[ 26.575871] kasan_save_stack+0x24/0x50
[ 26.576157] kasan_save_track+0x14/0x30
[ 26.576418] __kasan_kmalloc+0x7f/0x90
[ 26.576668] __kmalloc_noprof+0x281/0x6c0
[ 26.576938] nvme_alloc_ns+0x7f7/0x3170
[ 26.577206] nvme_scan_ns+0x508/0x880
[ 26.577449] async_run_entry_fn+0x8c/0x350
[ 26.577723] process_scheduled_works+0xb6f/0x1a00
[ 26.578034] worker_thread+0x4ad/0xb40
[ 26.578283] kthread+0x34f/0x450
[ 26.578501] ret_from_fork+0x563/0x800
[ 26.578752] ret_from_fork_asm+0x1a/0x30
[ 26.579012]
[ 26.579124] Freed by task 237:
[ 26.579335] kasan_save_stack+0x24/0x50
[ 26.579596] kasan_save_track+0x14/0x30
[ 26.579855] kasan_save_free_info+0x3a/0x60
[ 26.580131] __kasan_slab_free+0x43/0x70
[ 26.580388] kfree+0x321/0x500
[ 26.580591] nvme_ns_head_chr_release+0x39/0x50
[ 26.580883] __fput+0x352/0xa70
[ 26.581095] fput_close_sync+0xd8/0x190
[ 26.581350] __x64_sys_close+0x79/0xd0
[ 26.581595] do_syscall_64+0x117/0x6b0
[ 26.581842] entry_SYSCAL
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Skip detached progs in trampoline images that are still in use
bpf_tramp_image_put() makes sure a trampoline image is not freed while
a task may still be running in it, but nothing similar is done for the
progs called by that image. Detach drops the last prog reference right
away and the prog is freed after grace periods, on the basis that a
task still in the traced function skips the fexit progs once the nop at
ip_after_call is patched to a jump.
That leaves out a task sleeping in a sleepable prog that runs before
the detached one, which no grace period waits for:
CPU 0 CPU 1
in image I, sleeping in prog S
detach P from I's trampoline
-> new image, bpf_tramp_image_put(I)
bpf_prog_put(P), last ref
grace periods, P freed
back from S
__bpf_prog_enter(P)
call P->bpf_func
If S and P are fexit progs the task is already past the patched jump,
and fentry only images don't have one. On x86 this is an int3 in
poisoned bpf_prog_pack memory:
Oops: int3: 0000 [#1] SMP NOPTI
CPU: 18 UID: 0 PID: 94573 Comm: x169 Not tainted 6.18.44 #1 PREEMPT(lazy)
RIP: 0010:0xffffffffc0601d8d
Call Trace:
<TASK>
? bpf_trampoline_6442515411+0x1a4/0x21b
bpf_lsm_bprm_committed_creds+0x5/0x10
security_bprm_committed_creds+0x5f/0x70
begin_new_exec+0x2d6/0x410
...
We hit this in production when progs attached through trampolines got
detached while their hooks were busy, and it was independently found
with a fuzzer and KASAN.
Have the JITs emit a patchable nop in front of each prog call sequence
and record it in the image. When a prog is detached, patch its nop to a
jump over the call sequence. Progs that stay attached keep running for
the tasks that are in the image, and ip_after_call isn't needed anymore.
The task can be in any image that isn't freed yet, not only in the
current one. It sleeps in image I1 that calls S, P and Q, then P is
detached and the trampoline moves to image I2, then Q is detached and
its call is still in I1. So the trampoline keeps a list of its images
until they are freed, and detaching a prog patches its nop in all of
them. Images hold a reference on the trampoline for that long.
On riscv and loongarch a jump of any range takes several instructions,
and a task preempted in the middle of them could resume into half of the
new sequence. The nop is a single instruction there, patched to a near
branch through arch_bpf_trampoline_skip().
With the extra nops, BPF_MAX_TRAMP_LINKS progs no longer fit in a page
on x86 and arm64 (and already didn't on powerpc), so lower the limit
there like s390 does. |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: caiaq: unregister the input device when probe fails
setup_card() registers the input device, whose name and phys point into
struct snd_usb_caiaqdev, and then goes on to snd_card_register() and
snd_usb_caiaq_control_init(). If either fails, snd_probe() calls
snd_card_free(), which frees the device state but leaves the input
device registered: card_free() only clears the pointer, and the input
device is unregistered from snd_disconnect() alone. Reading its "uevent"
attribute afterwards dereferences freed memory:
BUG: KASAN: slab-use-after-free in string+0x4a9/0x4f0
Read of size 1 at addr ffff8880208f5043 by task caiaq/4967
add_uevent_var+0x183/0x3a0
input_dev_uevent+0x162/0x900
dev_uevent+0x2f1/0x870
uevent_show+0x1ca/0x3a0
...
Unregister the input device on the probe error path, as
snd_disconnect() does. snd_usb_caiaq_input_disconnect() is a no-op when
no input device was registered.
Reproduced with a raw-gadget Audio Kontrol 1 and a temporary hack that
makes snd_usb_caiaq_control_init() fail. |
| odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. Prior to version 25.12, odhcpd's DHCPv6 IA handler keeps a per-message `first` lease pointer so multiple IA options in one message reuse the same Reconfigure authentication key. A DHCPv6 REQUEST from an adjacent-network client can make the first IA set `first`, then make a later same-IAID IA fail the on-link check and free that same lease, leaving `first` dangling. A following IA in the same packet allocates a new lease and copies `first->key`, producing a 16-byte heap-use-after-free read. ASan confirms the UAF; native tracing shows the packet shape can deterministically reclaim the freed lease as the destination allocation, producing a zeroed Reconfigure key copy. The validated impact is unauthenticated adjacent-network denial of service and DHCPv6 Reconfigure/ForceRenew key confusion. Arbitrary PC control is not proven for this UAF alone. This issue has been patched in version 25.12. |
| Use after free in WebAppInstalls in Google Chrome on on Android prior to 156.0.8078.47 allowed a remote attacker to execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: High) |
| Use after free in SiteIsolation in Google Chrome on on Android prior to 156.0.8078.47 allowed a remote attacker to execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: Medium) |
| In the Linux kernel, the following vulnerability has been resolved:
usb: cdns3: fix use-after-free in cdns3_gadget_exit()
cdns3_gadget_start() arms two works on system_freezable_wq:
pending_status_wq for the deferred ep0 status stage and aligned_buf_wq
for realigned request buffers. Both handlers use the cdns3_device the
works are embedded in, and cdns3_pending_setup_status_handler() also
calls the ep0 request completion.
cdns3_gadget_exit() does not wait for these works. It frees all
endpoints and aligned buffers and drops the last reference to the
gadget device, which frees priv_dev, so a work queued before the exit
can run after the free.
Fix this by waiting for both works after the gadget driver is unbound
and the IRQ is freed, when no new work can be queued, and before the
endpoints and buffers are released.
This issue was found by an in-house static analysis tool. |
| In the Linux kernel, the following vulnerability has been resolved:
usb: typec: ucsi: glink: fix use-after-free of ucsi on remove
The pmic_glink client is released by the devres cleanup, which runs
after pmic_glink_ucsi_remove() has returned, so its notification
callbacks can queue work until then. Work that runs after
ucsi_unregister() has been called touches freed state: it dereferences
the connector array that ucsi_unregister() freed, or registers and
unregisters the instance a second time.
Disable both work items with disable_work_sync() before unregistering,
and unregister only if the instance is still registered.
This issue was found by an in-house static analysis tool. |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_conn: Lock parent access during enhanced SCO setup
Bluetooth: hci_conn: Lock parent access during enhanced SCO setup
hci_enhanced_setup_sync() runs on the request workqueue without the
hci_dev_lock held by its caller when setup was queued. Its CVSD
capability check and find_next_esco_param() dereference conn->parent
while the receive workqueue can unlink and release that parent.
The following interleaving can cause a use-after-free:
hci_enhanced_setup_sync() hci_disconn_complete_evt()
load conn->parent
hci_dev_lock()
hci_conn_del(ACL parent)
unlink SCO child
drop link's parent reference
clear child->parent
release ACL parent
bt_link_release()
kfree(parent)
hci_dev_unlock()
read parent->features[0][3]
The reference held for the queued SCO child does not keep its ACL parent
alive after unlinking. Commit 42de40abe25d ("Bluetooth: hci_conn: fix the
SCO setup context lifetime") protects the child stored in the queued
context, but leaves these parent accesses unprotected.
With a 40 ms diagnostic delay after loading conn->parent, an instrumented
kernel based on fd179f8a05be, which already contains 42de40abe25d,
BUG: KASAN: slab-use-after-free in hci_enhanced_setup_sync+0xda5/0xdf0
Read of size 1 at addr ffff888102204047 by task kworker/u17:0/93
Call Trace:
hci_enhanced_setup_sync+0xda5/0xdf0
hci_cmd_sync_work+0x13c/0x290
process_one_work+0x6b4/0x10e0
Allocated by task 92:
__hci_conn_add+0x304/0x1df0
hci_connect_acl+0x349/0x3e0
hci_connect_sco+0x3b/0x9a0
sco_sock_connect+0x475/0xca0
Freed by task 94:
kfree+0x121/0x3c0
bt_link_release+0x79/0xa0
device_release+0xc8/0x240
kobject_put+0x14d/0x280
hci_conn_del+0x524/0xe30
hci_disconn_complete_evt+0x403/0x8c0
hci_event_packet+0x71b/0xb20
hci_rx_work+0x293/0x730
The accessed address is 71 bytes into the freed ACL parent, at its
features[0][3] byte; the queued SCO child is a different object. The
diagnostic preserves the loaded parent across the delay, matching the
unmodified compiled capability check, and does not change the parent
references or teardown path.
Hold hci_dev_lock() across the codec switch, including every call to
find_next_esco_param(), and release it on all selection errors. Keep
configure_datapath_sync() outside the critical section because it waits
for HCI events. Preserve parameter selection and existing return values. |
