| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
rds: tcp: hold the RCU lock across ipv6_chk_addr() in rds_tcp_laddr_check()
rds_tcp_laddr_check() looks up a scoped IPv6 interface with
dev_get_by_index_rcu(), drops the RCU read-side lock, and only then
passes the bare struct net_device * into ipv6_chk_addr().
dev_get_by_index_rcu() only keeps the device alive within the same RCU
read-side section. After rcu_read_unlock(), a concurrent RTM_DELLINK can
free the net_device; ipv6_chk_addr() then dereferences the stale pointer
in __ipv6_chk_addr_and_flags() (e.g. l3mdev_master_dev_rcu(dev)), reading
freed memory.
Keep the RCU read-side lock held across the ipv6_chk_addr() call instead
of dropping it right after the lookup, so the device cannot be freed
while it is in use.
BUG: KASAN: slab-use-after-free in __ipv6_chk_addr_and_flags (... net/ipv6/addrconf.c:1998)
Read of size 8 at addr ffff8880106ec000 by task exploit/153
Call Trace:
...
kasan_report (mm/kasan/report.c:595)
__ipv6_chk_addr_and_flags (... net/ipv6/addrconf.c:1998)
ipv6_chk_addr (net/ipv6/addrconf.c:2031 net/ipv6/addrconf.c:1972)
rds_tcp_laddr_check (net/rds/tcp.c:370)
rds_bind (net/rds/bind.c:248)
__sys_bind (net/socket.c:1920)
__x64_sys_bind (net/socket.c:1956)
do_syscall_64 (arch/x86/entry/syscall_64.c:63)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: Fix buffer overflow in SDMA queue checkpoint/restore on GFX11
The v11 MQD manager incorrectly assigned the CP-compute variants of
checkpoint_mqd/restore_mqd for KFD_MQD_TYPE_SDMA queues. These functions
use sizeof(struct v11_compute_mqd) (2048 bytes) instead of sizeof(struct
v11_sdma_mqd) (512 bytes), causing a 1536-byte overflow.
During CRIU checkpoint of an SDMA queue on Navi3x:
- checkpoint_mqd() reads 2048 bytes from a 512-byte SDMA MQD buffer,
leaking 1536 bytes of adjacent GTT memory to userspace
During CRIU restore:
- restore_mqd() writes 2048 bytes into a 512-byte SDMA MQD buffer,
corrupting 1536 bytes of adjacent GTT memory (often the ring buffer
or neighboring MQDs)
This is a copy-paste regression unique to v11. All other ASIC backends
(cik, vi, v9, v10, v12) correctly use the SDMA-specific variants.
Add checkpoint_mqd_sdma() and restore_mqd_sdma() functions that properly
handle the smaller v11_sdma_mqd structure, matching the pattern used in
other MQD managers.
(cherry picked from commit 6fa41db7ffdec97d62433adf03b7b9b759af8c2c) |
| In the Linux kernel, the following vulnerability has been resolved:
hwmon: (nct6775-core) Fix number of temperature registers for NCT6116
Unlike NCT6106, NCT6116 only has three temperature registers, and with
it only three temperature source and temperature source configuration
registers. The register addresses match those of NCT6106 and can be
re-used.
The code used a separate array to list the temperature source registers
for NCT6116, but used the size of the NCT6106 register array to set
the number of registers. The NCT6106 register array provides six addresses,
while the temperature source register array for NCT6116 only provides three
addresses. This causes a KASAN report.
BUG: KASAN: global-out-of-bounds in nct6775_probe+0x936/0x46f0 [nct6775]
Read of size 2 at addr ffffffffc19561a6 by task modprobe/954
...
Call Trace:
dump_stack+0x7d/0xa7
print_address_description.constprop.0+0x1c/0x220
? __kasan_kmalloc.constprop.0+0xc9/0xd0
? __kmalloc_node_track_caller+0x194/0x5b0
? nct6775_probe+0x936/0x46f0 [nct6775]
? nct6775_probe+0x936/0x46f0 [nct6775]
...
Fix the problem by hard-coding the number of temperature and temperature
configuration registers to three for NCT6116. Drop the unnecessary
NCT6116_REG_TEMP_SOURCE array and re-use NCT6106_REG_TEMP_SOURCE. |
| In the Linux kernel, the following vulnerability has been resolved:
hwmon: (nzxt-smart2) DMA-align output buffer
Sashiko reports:
When send_output_report() calls hid_hw_output_report(), the underlying USB
HID core calls usb_interrupt_msg() which maps this buffer directly for DMA.
When the DMA mapping flushes or invalidates the cacheline, it will corrupt
the adjacent variables (mutex, update_interval) that were modified
concurrently by the CPU. This causes memory corruption due to cacheline
sharing on non-coherent CPU architectures (such as ARM or MIPS). The DMA
API debugging tool (CONFIG_DMA_API_DEBUG) will trigger runtime warnings
for this violation.
Any operation that triggers send_output_report() (like setting a fan speed
or updating the interval) causes the USB DMA mapping. On systems with
non-coherent caches, this structural bug causes immediate and deterministic
memory corruption.
Align the output buffer to ARCH_DMA_MINALIGN to fix the problem. |
| In the Linux kernel, the following vulnerability has been resolved:
hwmon: (adt7470) Fix busy-loop and I2C flooding in update thread
When userspace configures 'auto_update_interval' to 0 via sysfs, the
background kthread executes schedule_timeout_interruptible(0), which
returns immediately.
If 'num_temp_sensors' is concurrently or previously set to 0, the
msleep_interruptible() delay inside adt7470_read_temperatures() also
becomes 0. This combination forces the background thread into a tight,
unbounded busy-loop, hogging the CPU and flooding the I2C bus with a
continuous stream of transactions.
Fix this vulnerability by raising the lower limit of the clamp_val in
auto_update_interval_store() from 0 to 500 milliseconds. This guarantees
a reasonable minimum sleep window between sensor updates, protecting the
system from intentional or accidental I2C bus denial of service. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: SVM: Update x2APIC MSR intercepts if AVIC is inhibited while L2 is active
Always update x2APIC MSR intercepts for L1 when AVIC is deactivated, even
if L2 is active and KVM is using a separate MSR bitmap to run L2. If AVIC
is fully enabled prior to running L2, and is then inhibited while L2 is
active (for a VM-scoped inhibit), then KVM will run L1 with AVIC disabled,
but with x2APIC MSR intercepts disabled, i.e. will allow L1 to read most of
the host's APIC state, send arbitrary interrupts, change task priority, and
ultimately trivially DoS the host.
E.g. sending a self-IPI in L1 on HYPERV_REENLIGHTENMENT_VECTOR, 0xee, with
CONFIG_HYPERV=n in the host kernel as a "safe" PoC, yields:
Spurious interrupt (vector 0xee) on CPU#425. Acked
And hacking KVM to abuse kvm_set_posted_intr_wakeup_handler() to register a
handler and WARN on POSTED_INTR_WAKEUP_VECTOR yields:
------------[ cut here ]------------
WARNING: arch/x86/kvm/svm/svm.c:5594 at pi_wakeup_handler+0x9/0x10 [kvm_amd], CPU#156: nested_x2apic_t/316940
CPU: 156 UID: 0 PID: 316940 Comm: nested_x2apic_t Tainted: G S U
Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER
Hardware name: Google Astoria-Turin/astoria, BIOS 0.20260209.0-0 02/09/2026
RIP: 0010:pi_wakeup_handler+0x9/0x10 [kvm_amd]
Call Trace:
<IRQ>
sysvec_kvm_posted_intr_wakeup_ipi+0x64/0x80
</IRQ>
<TASK>
asm_sysvec_kvm_posted_intr_wakeup_ipi+0x1a/0x20
RIP: 0010:vcpu_run+0x1430/0x1e40 [kvm]
kvm_arch_vcpu_ioctl_run+0x2c1/0x600 [kvm]
kvm_vcpu_ioctl+0x580/0x6b0 [kvm]
__se_sys_ioctl+0x6d/0xb0
do_syscall_64+0x10a/0x480
entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x46ff4b
</TASK>
---[ end trace 0000000000000000 ]--- |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: s390: pci: Reject adapter interrupt forwarding if already enabled
The MPCIFC instruction doesn't allow registering adapter interrupts without
first unregistering. So reject any request to enable interrupt forwarding
if its already enabled for the zPCI device. This also fixes overwriting and
thus leaking resources when the ioctl is called multiple times for the same
device. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: mwifiex: use the subframe length when parsing A-MSDU TDLS frames
mwifiex_11n_dispatch_amsdu_pkt() splits an A-MSDU with
ieee80211_amsdu_to_8023s() and walks the resulting subframes. For each
subframe it passes the subframe data pointer to
mwifiex_process_tdls_action_frame(), but pairs it with skb->len, the
length of the A-MSDU parent, instead of rx_skb->len:
rx_skb = __skb_dequeue(&list);
rx_hdr = (struct rx_packet_hdr *)rx_skb->data;
if (ISSUPP_TDLS_ENABLED(priv->adapter->fw_cap_info) &&
ntohs(rx_hdr->eth803_hdr.h_proto) == ETH_P_TDLS) {
mwifiex_process_tdls_action_frame(priv, (u8 *)rx_hdr,
skb->len);
}
The parent is not a valid description of that buffer, and may not be
valid memory at all. ieee80211_amsdu_to_8023s() ends with
if (!reuse_skb)
dev_kfree_skb(skb);
and it only sets reuse_skb when the parent is linear, is not a
head_frag, and is being consumed as the *last* subframe. So when the
parent does not qualify for reuse it has already been freed, and the
read of skb->len is a use-after-free. When it is reused, skb->len is
the length of the last subframe, applied to every earlier subframe,
which over-states the buffer whenever an earlier subframe is shorter.
The callee cannot absorb a wrong length, because it derives its own
ceiling from the value it is given. Each frame type computes
ies_len = len - sizeof(struct ethhdr) - TDLS_*_FIX_LEN;
and the element walk is then bounded entirely against that ceiling,
for (end = pos + ies_len; pos + 1 < end; pos += 2 + pos[1]) {
u8 ie_len = pos[1];
if (pos + 2 + ie_len > end)
break;
so a too-large len moves end past the end of the subframe and the walk
reads and copies beyond it. The A-MSDU layout is chosen by the sender,
which makes the difference between the last subframe and a shorter
earlier one remotely selectable. Reaching this requires TDLS support in
firmware and the TDLS ethertype on the subframe.
The other caller, mwifiex_process_rx_packet(), is correct: it passes a
pointer and a length that describe the same region of the RX buffer.
Pass rx_skb->len, the length of the subframe actually being parsed. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/huge_memory: unlock i_mmap_rwsem before releasing after-split folios
__folio_split() keeps dereferencing the mapping after the split:
shmem_uncharge(mapping->host) and remap_page() while the folios are still
frozen/locked, and i_mmap_unlock_read(mapping) at the very end, after the
after-split folios have been unlocked and freed.
Nothing holds an inode reference across that. The split relies on @folio
-- which the beyond-EOF drop loop never removes, as it starts at
folio_next(folio) -- staying locked and in the page cache to hold off
eviction. But the unlock loop unlocks @folio before i_mmap_unlock_read()
runs. If the caller's @lock_at is a tail beyond EOF, as memory_failure()
passes when splitting a poisoned tail of a shmem THP that reaches past
i_size during truncation, it too is gone from the page cache; so once
@folio is unlocked no locked, in-cache folio pins the inode, and a
concurrent final iput() can evict and RCU-free it before
i_mmap_unlock_read() touches i_mmap_rwsem:
BUG: KASAN: slab-use-after-free in __up_read+0x634/0x790
i_mmap_unlock_read include/linux/fs.h:537 [inline]
__folio_split+0x732/0x1640 mm/huge_memory.c:4100
try_to_split_thp_page+0xab/0x390 mm/memory-failure.c:1675
memory_failure+0x1394/0x26e0 mm/memory-failure.c:2470
Freed by task 4601:
shmem_free_in_core_inode+0x54/0xb0 mm/shmem.c:5177
evict+0x57f/0xac0 fs/inode.c:870
Do every mapping dereference while @folio still pins the inode: drop
i_mmap_rwsem right after remap_page(), before the loop that unlocks and
frees the after-split folios, and clear @mapping so the exit path does not
unlock it again. shmem_uncharge() and remap_page() already run before
that point, so after this nothing past the unlock loop touches the inode
or the mapping.
This is now a rule the split depends on, alongside keeping @folio frozen
until the page cache is updated: no inode or mapping dereference once the
after-split folios start being unlocked. |
| In the Linux kernel, the following vulnerability has been resolved:
um: vector: fix use-after-free in vector_mmsg_rx()
When vector_mmsg_rx() discards a packet whose overlay header fails
verify_header(), it frees the skb and continues the loop:
if (header_check < 0) {
dev_kfree_skb_irq(skb);
vp->estats.rx_encaps_errors++;
continue;
}
The normal and short-packet paths fall through to the bottom of the
loop body, which clears the consumed slot and advances the cursors:
(*skbuff_vector) = NULL;
mmsg_vector++;
skbuff_vector++;
The verify_header() < 0 path skips that via continue, so the freed skb
is left in skbuff_vector[] and the cursors do not advance. The next
iteration reads the same slot, gets the freed skb, and frees it again,
producing a refcount underflow / use-after-free in the RX path.
Discard the slot the same way the other paths do before continuing.
Only transports whose verify_header() can return negative are affected:
GRE and L2TPv3 do so on a cookie/session-id mismatch (raw/tap do not),
so any peer on such a transport can trigger it without authentication. |
| In the Linux kernel, the following vulnerability has been resolved:
ublk: reset kernel-owned dev_info fields in ublk_ctrl_add_dev()
ublk_ctrl_add_dev() memcpy()s the userspace ublksrv_ctrl_dev_info into
ub->dev_info and then fixes up the fields the driver owns, but misses
->state and ->ublksrv_pid.
A device added with ->state = UBLK_S_DEV_LIVE passes the
"->state != UBLK_S_DEV_DEAD" test that ublk_stop_dev_unlocked() uses as its
proxy for "a disk is attached", while ->ub_disk is still NULL, so DEL_DEV
right after ADD_DEV oopses in del_gendisk(). UBLK_S_DEV_QUIESCED plus
UBLK_F_USER_RECOVERY dies one step earlier, in ublk_force_abort_dev(). A
poisoned ->state also gets START_USER_RECOVERY and the char device
read/write path onto a device that was never started, and wedges START_DEV
at -EEXIST. A poisoned ->ublksrv_pid just makes GET_DEV_INFO report an
unrelated task as the ublk server.
Reset both after the memcpy(), as ublk_detach_disk() does. Userspace only
ever reads these back, so correcting them silently breaks nothing.
ADD_DEV has copied ->state in unsanitized since ublk was merged, but back
then it was harmless: the gendisk was allocated during ADD_DEV, and both
teardown and the START_DEV -EEXIST check keyed off disk_live() rather than
->state. The oops became reachable once the disk allocation moved to
START_DEV and those checks switched to ->state. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv6: fib6: fix NULL deref in fib6_walk_continue() on multi-batch dump
inet6_dump_fib() saves its progress in cb->args[1] as a positional
index within the current hash chain. Between batches, a concurrent
fib6_new_table() can insert a new table at the chain head, shifting
all existing entries. The saved index then lands on a different
table, causing fib6_dump_table() to set w->root to the wrong table
while w->node still points into the previous one.
fib6_walk_continue() dereferences w->node->parent (NULL) and panics:
BUG: kernel NULL pointer dereference, address: 0000000000000008
RIP: 0010:fib6_walk_continue+0x6e/0x170
Call Trace:
<TASK>
fib6_dump_table.isra.0+0xc5/0x240
inet6_dump_fib+0xf6/0x420
rtnl_dumpit+0x30/0xa0
netlink_dump+0x15b/0x460
netlink_recvmsg+0x1d6/0x2a0
____sys_recvmsg+0x17a/0x190
Fix by storing tb->tb6_id in cb->args[1] instead of a positional
index. On resume, skip entries until the id matches; a concurrent
head-insert can never match the saved id, so the walker always
resumes on the correct table. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: libsas: Fix HA resume deadlock and hisi_sas disk-wake race
Commit fbefe22811c3 ("scsi: libsas: Don't always drain event workqueue
for HA resume") introduced sas_resume_ha_no_sync() to avoid a deadlock:
the PHYE_RESUME_TIMEOUT handler, running on the HA event workqueue,
calls sas_deform_port() -> sas_destruct_devices(), which removes SCSI
devices and waits for the host to become runtime-active. But the host
cannot resume until sas_resume_ha() -> sas_drain_work() returns, and the
drain is blocked on that very handler.
However skipping the drain reintroduces a race: hisi_sas returns from
resume before all PHY UP work and libsas discovery work finish. The
controller may then autosuspend while disks are still waking up. The
disks issue IO to a suspended controller, the IO fails, and the disks
get disabled.
Fix the deadlock at its source by moving the PHYE_RESUME_TIMEOUT
notification to after sas_drain_work(). By then the host resume is about
to complete, so device removal through device_link no longer blocks on
the resume and the cycle is broken.
With the deadlock gone, restore sas_resume_ha() (the draining variant)
in hisi_sas and remove sas_resume_ha_no_sync().
The reorder is safe for the other libsas consumers (isci, pm8001,
aic94xx, mvsas). During suspend, sas_suspend_devices() calls
sas_notify_lldd_dev_gone() for each device, which sets dev->lldd_dev to
NULL. When scsi_unblock_requests re-enables I/O in resume, any I/O to a
timed-out phy's disk is immediately rejected by the LLDD before reaching
hardware: isci returns SAS_DEVICE_UNKNOWN (mapped to DID_BAD_TARGET),
and pm8001 returns SAS_PHY_DOWN (mapped to DID_NO_CONNECT). Both
complete directly via scsi_done() without entering SCSI EH. This is
identical in both the old and new ordering since lldd_dev_gone runs
during suspend, before resume. The reorder only affects when the
PHYE_RESUME_TIMEOUT handler runs (synchronized by sas_drain_work()
vs. asynchronous after resume returns), not whether I/O can reach the
device. aic94xx and mvsas do not register any PM ops and never reach
this code path. |
| In the Linux kernel, the following vulnerability has been resolved:
hwmon: (nct6775-core) Prevent access to unsupported weight registers
Sashiko reports:
During initialization of the nct6116 chip, the driver sets data->pwm_num
to 5. However, it assigns several NCT6106 register arrays (such as
NCT6106_REG_WEIGHT_DUTY_STEP, NCT6106_REG_WEIGHT_TEMP_SEL, and
NCT6106_REG_WEIGHT_TEMP_*) to data->REG_PWM and data->REG_WEIGHT_TEMP.
These arrays only contain 3 elements.
In nct6775_update_pwm(), the driver iterates up to data->pwm_num. If
data->has_pwm has bits 3 or 4 set (which is structurally possible for
nct6116), the loop attempts to read elements at index 3 and 4 from these
3-element arrays. This results in a global out-of-bounds read, which can
be caught by KASAN.
Furthermore, the driver uses these garbage out-of-bounds values as
hardware register addresses for subsequent read and write operations. This
leads to invalid hardware register access, potentially causing hardware
misconfiguration or system crashes.
The underlying problem is that the chip does support up to five fan
control channels, but only the first three support weight control.
Fix the problem by extending the affected weight register arrays with
zeroed fields. The driver uses zeroed register addresses to determine
if a register is supported or not, and skips accesses for unsupported
registers. |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: usb-audio: fix OOB write in snd_usbmidi_akai_output()
snd_usbmidi_akai_output() computes its fill-loop bound
buf_end = ep->max_transfer - MAX_AKAI_SYSEX_LEN - 1;
as a signed int, so a small device-advertised bulk-OUT max_transfer
makes buf_end negative. The loop guard then compares the u32
urb->transfer_buffer_length against that negative int: the usual
arithmetic conversion turns buf_end into a large unsigned value, so the
guard stays true and each iteration keeps appending SysEx framing and
payload bytes past the end of the URB transfer buffer, which is only
max_transfer bytes long.
A USB device that advertises a tiny bulk-OUT endpoint can therefore
trigger an attacker-length- and content-controlled heap out-of-bounds
write when a process writes to the created /dev/snd/midiC*D* node.
Return early when there is no room for even one SysEx, so the loop is
never entered with a bound that would wrap. The loop is the last
statement of the function, so bailing out is equivalent to it not
running.
Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com> |
| In the Linux kernel, the following vulnerability has been resolved:
net: openvswitch: fix skb leak on flow key update failure during ct
ovs_ct_execute() always steals or frees the skb on failure while
ovs_flow_key_update() does not. So, if it fails and we return right
away, the skb ends up leaked.
Fix that by breaking instead and letting the common error handling
code at the bottom of the loop to free the skb properly.
This is a very unlikely scenario as it requires the packet to become
unparseable by applying a set of actions on a previously parseable skb,
but should be fixed nevertheless.
Reported by Sashiko. |
| In the Linux kernel, the following vulnerability has been resolved:
perf/x86/amd/brs: Fix kernel address leakage
A user-only branch stack can contain branches that originate from
the kernel. As a result, kernel addresses are exposed to user space
even when PERF_SAMPLE_BRANCH_USER is requested. On AMD processors
supporting X86_FEATURE_BRS (Zen 3 only), perf can still report entries
such as SYSRET/interrupt returns for which the branch-from addresses
are in the kernel.
E.g.
$ perf record -j any,u -c 4000 -e branch-brs -o - -- \
perf bench syscall basic --loop 1000 | \
perf script -i - -F brstack|tr ' ' '\n'| \
grep -E '0x[89a-f][0-9a-f]{15}'
...
0xffffffff810001c4/0x72e2e32955eb/-/-/-/0//-
0xffffffff810001c4/0x72e2d94a9821/-/-/-/0//-
0xffffffff810001c4/0x72e2d94ffa1b/-/-/-/0//-
...
BRS provides no hardware branch filtering, so privilege level
filtering is performed entirely in software. However, amd_brs_match_plm()
only validates the branch-to address against the requested privilege
levels. For branches from the kernel to user space, the branch-from
address is left unchecked and is leaked. Extend the software filter to
also validate the branch-from address, so that any branch record whose
branch-from address is in the kernel is dropped when
PERF_SAMPLE_BRANCH_USER is requested. |
| In the Linux kernel, the following vulnerability has been resolved:
mips: sched: Fix CPUMASK_OFFSTACK memory corruption
This patch addresses a critical memory management flaw. When
CONFIG_CPUMASK_OFFSTACK is enabled, cpumask_var_t is a pointer.
Consequently, sizeof(new_mask) evaluates to the pointer size, causing
copy_from_user() to clobber the mask pointer. Furthermore, the old
logic performed copy_from_user() before allocating the mask.
Fix this by allocating new_mask first. To handle variable-sized user
masks correctly, use cpumask_size() to truncate overly large user masks
or pad undersized masks with zeros before copying the data directly into
the allocated buffer. |
| In the Linux kernel, the following vulnerability has been resolved:
can: isotp: serialize TX state transitions under so->rx_lock
The TX state machine (so->tx.state) is driven from three contexts:
sendmsg() claiming and progressing a transfer, the RX path consuming
Flow Control/echo frames, and two hrtimers timing out a stalled
transfer. Mixing a lock-free cmpxchg() claim in sendmsg() with
hrtimer_cancel() calls made under so->rx_lock elsewhere left windows
where a frame or timer callback could act on a state that had already
moved on, corrupting an unrelated transfer.
so->rx_lock now covers the full lifecycle of a TX claim: sendmsg()
takes it to check so->tx.state is ISOTP_IDLE, switch it to
ISOTP_SENDING, bump so->tx_gen and drain the previous transfer's
timers - all as one critical section. isotp_rcv_fc()/isotp_rcv_cf()
already run under this lock via isotp_rcv(), and isotp_rcv_echo() now
takes it itself, so none of them can ever observe a transfer mid-claim.
This also means a transfer can no longer be handed to sendmsg()'s
cleanup paths (signal or send error) while another thread is
concurrently claiming or finishing it, so those paths can cancel
timers and reset the state unconditionally.
isotp_release() claims the socket the same way, so a racing sendmsg()
sees a consistent ISOTP_SHUTDOWN and skips arming its timer or sending.
Only the hrtimer callbacks stay outside so->rx_lock, since they run
under so->rx_lock's cancellation elsewhere and taking it themselves
would deadlock. so->tx_gen lets them recognize whether the transfer
they timed out is still the one currently active, so they don't
report an error against a transfer that has since completed or been
superseded. |
| In the Linux kernel, the following vulnerability has been resolved:
can: bcm: defer rx_op deallocation to workqueue to fix thrtimer UAF
Commit f1b4e32aca08 ("can: bcm: use call_rcu() instead of costly
synchronize_rcu()") replaced synchronize_rcu() in bcm_delete_rx_op()
with call_rcu() and introduced the RX_NO_AUTOTIMER flag.
However, this flag check was omitted for thrtimer in the packet rx
fast-path. During BCM RX operation teardown, a concurrent RCU reader
(bcm_rx_handler) can race and re-arm thrtimer via
bcm_rx_update_and_send() after call_rcu() has been scheduled. Once
the RCU grace period elapses, bcm_op is freed. The subsequently
firing thrtimer then dereferences the deallocated op, causing a UAF.
Adding flag checks to the rx fast-path (bcm_rx_update_and_send) does not
fully close the TOCTOU race and introduces latency for every CAN frame.
Conversely, calling hrtimer_cancel() directly inside the RCU callback
(softirq context) is fatal as hrtimer_cancel() can sleep, triggering
a "scheduling while atomic" panic.
Resolve this by deferring the timer cancellation and memory free to a
dedicated unbound workqueue (bcm_wq). The RCU callback now queues a
work item to bcm_wq, which safely cancels both timers and deallocates
memory in sleepable process context. A dedicated workqueue is used to
prevent system-wide WQ saturation and is cleanly flushed/destroyed
on module unload to avoid rmmod page faults.
Since the deferred work can now outlive the calling context by an
unbounded amount, also take a reference on op->sk when it is assigned
and drop it only once the deferred work has cancelled both timers, so a
socket can no longer be freed out from under a still-armed timer whose
callback (bcm_send_to_user()) dereferences op->sk. |
