| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
af_packet: Don't cast tpacket_hdr.tp_len to int in tpacket_parse_header().
syzbot reported BUG() in sock_sendmsg_nosec(). [0]
The problem is that tpacket_parse_header() casts user-provided
tpacket_hdr.tp_len, which is u32, to int.
If the length is larger than INT_MAX, the following condition
in tpacket_parse_header() passes,
if (unlikely(tp_len > size_max))
and any negative value can be returned to the caller, up to
sock_sendmsg_nosec().
The repro set tpacket_hdr.tp_len to 0xfffffdef, which is cast
to -EIOCBQUEUED (-529), triggering BUG() in sock_sendmsg_nosec().
*(uint64_t*)0x200000000008 = 0xfffffdef;
...
syscall(__NR_write, /*fd=*/r[0], /*buf=*/0x200000000000ul, /*count=*/1ul);
Let's define the local tp_len as u32 in tpacket_parse_header().
[0]:
kernel BUG at net/socket.c:803!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 5628 Comm: syz-executor176 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:sock_sendmsg_nosec+0x145/0x180 net/socket.c:803
Code: 06 67 48 0f b9 3a eb 95 e8 e8 3a 22 f8 48 89 df 4c 89 f6 4c 89 e2 4d 89 fb 2e e8 32 a5 5c 16 e9 51 ff ff ff e8 cc 3a 22 f8 90 <0f> 0b e8 c4 3a 22 f8 48 83 c3 18 48 89 d8 48 c1 e8 03 42 80 3c 28
RSP: 0018:ffffc90003aefb48 EFLAGS: 00010293
RAX: ffffffff89a578d4 RBX: ffff8880764c67c0 RCX: ffff88807fb23e80
RDX: 0000000000000000 RSI: 00000000fffffdef RDI: 00000000fffffdef
RBP: 00000000fffffdef R08: ffffc90003aef747 R09: 1ffff9200075dee8
R10: dffffc0000000000 R11: fffff5200075dee9 R12: 0000000000000001
R13: dffffc0000000000 R14: ffffc90003aefbc0 R15: ffffffff8aac4310
FS: 000055559101b400(0000) GS:ffff888124ce0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000210 CR3: 0000000073dca000 CR4: 00000000003526f0
Call Trace:
<TASK>
__sock_sendmsg net/socket.c:815 [inline]
sock_write_iter+0x2de/0x3e0 net/socket.c:1266
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x612/0xba0 fs/read_write.c:687
ksys_write+0x150/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f173130ecb9
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 73 01 c3 48 c7 c1 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd67e44248 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007f173130ecb9
RDX: 0000000000000001 RSI: 0000200000000000 RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd67e44388
R13: 0000000000000002 R14: 00002000000000c0 R15: 0000000000000002
</TASK> |
| In the Linux kernel, the following vulnerability has been resolved:
staging: fbtft: make dirty_lock IRQ-safe
fbtft_mkdirty() can be reached from the fbcon rendering path while
processing printk() in hardirq context. Meanwhile, dirty_lock is also
taken by fbtft_deferred_io() in workqueue context with local interrupts
enabled.
Lockdep reports a possible IRQ lock inversion involving dirty_lock and
console_owner. A hardirq can interrupt a CPU holding dirty_lock and
enter the console rendering path, which can attempt to acquire
dirty_lock again.
The following lockdep report was observed on an RK3566 system with
CONFIG_PROVE_LOCKING enabled:
WARNING: possible irq lock inversion dependency detected
swapper/2/0 just changed the state of lock:
(console_owner){-...}-{0:0}
but this lock took another, HARDIRQ-unsafe lock in the past:
(&par->dirty_lock){+.+.}-{2:2}
CPU0 CPU1
---- ----
lock(&par->dirty_lock);
local_irq_disable();
lock(console_owner);
lock(&par->dirty_lock);
<Interrupt>
lock(console_owner);
*** DEADLOCK ***
Use spin_lock_irqsave() for fbtft_mkdirty() and spin_lock_irq() for
fbtft_deferred_io(). They only access the dirty line range, so the
IRQ-off regions remain short. |
| In the Linux kernel, the following vulnerability has been resolved:
ASoC: fsl_micfil: balance mclk enable/disable
hw_params() enables mclk unconditionally and hw_free() disables it
unconditionally, but the PCM core does not guarantee 1:1 pairing:
hw_free() can run without hw_params(), and hw_params() can be called
multiple times from the SETUP state. This triggers an "already
disabled" WARN() in the first case and leaks an enable reference in
the second, leaving the clock ungateable.
Guard both sides with the existing mclk_flag, as fsl_sai.c does with
mclk_streams. |
| In the Linux kernel, the following vulnerability has been resolved:
ASoC: amd: yc: fix memory leak in acp6x_pdm_dma_close()
acp6x_pdm_dma_close() does not free the runtime->private_data buffer
allocated in acp6x_pdm_dma_open(). Add the missing kfree. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: detach failed sprout device from transaction update list
When creating the first metadata chunk for a sprout filesystem,
create_chunk() adds the new device to the transaction dev_update_list
through device->post_commit_list.
If the subsequent system chunk creation fails, btrfs_init_new_device()
aborts the transaction and releases the device while post_commit_list is
still linked. This triggers a warning in btrfs_free_device() and leaves
the transaction list referencing freed memory.
Detach the device while holding chunk_mutex before releasing it. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: restore active device pointers after failed sprout
btrfs_init_new_device() switches latest_dev and possibly s_bdev from the
seed device to the new sprout device before creating the first writable
chunks.
If chunk creation or the subsequent sprout setup fails, the error path
releases the new device without switching those pointers back.
btrfs_show_devname() can then dereference the freed latest_dev and crash.
Restore the active device pointers to the latest seed device before
removing and releasing the failed sprout device. |
| In the Linux kernel, the following vulnerability has been resolved:
bonding: alb: fix uninitialized transport header access in alb_determine_nd()
alb_determine_nd() uses icmp6_hdr(skb) to inspect ICMPv6 headers.
However, in xmit paths (e.g. packets sent via AF_PACKET / raw sockets
or forwarded packets), skb->transport_header is not guaranteed to be
initialized. While pskb_network_may_pull() ensures the packet data is
linear starting from the network header, it does not set or adjust the
transport header offset.
Dereferencing icmp6_hdr(skb) can therefore access out-of-bounds memory.
Fetch the icmp6hdr directly after ipv6hdr following pskb_network_may_pull(),
and reload ipv6hdr in case pskb_may_pull() reallocated skb->head.
Also remove the unused bond argument from alb_determine_nd(). |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: mpt3sas: Avoid out-of-bounds cpumask_of_node() call in _base_assign_reply_queues()
dev_to_node() can return NUMA_NO_NODE (-1) on systems without NUMA
topology information for the PCI device, such as single-socket boards
that don't expose device-to-node affinity. Passing -1 directly into
cpumask_of_node() indexes node_to_cpumask_map[-1], an out-of-bounds
array read caught by UBSAN:
UBSAN: array-index-out-of-bounds in arch/x86/include/asm/topology.h:72:28
index -1 is out of range for type 'cpumask *[1024]'
Fall back to cpu_online_mask when no NUMA node is available, rather than
assuming dev_to_node() always returns a valid node index. |
| In the Linux kernel, the following vulnerability has been resolved:
sched/rt,dl: Skip migrate-disabled tasks when picking a push candidate
A migrate_disable()'d RT task cannot be moved to another CPU, but the
scheduler still keeps such a task on that CPU's pushable list
(rq->rt.pushable_tasks) and still marks the runqueue RT-overloaded
(rq->rt.overloaded = 1). So the RT balancer keeps treating this CPU as
having a task to move away, and keeps trying to move the task, but the
push can never succeed. When the head is pinned, push_rt_task() does not
give up either. It falls back to pushing rq->curr instead, using the
per-CPU stopper, as added by commit a7c81556ec4d ("sched: Fix
migrate_disable() vs rt/dl balancing").
The CPU spends tens of milliseconds in this retry loop. The core is
isolated for real-time work, but during the loop nearly half of its time
is consumed by pushes that cannot succeed.
An ftrace capture of the affected CPU, with sched_switch enabled and
commit 94894c9c477e ("sched/rt: Skip currently executing CPU in
rto_next_cpu()") applied, shows where the CPU time went. Two SCHED_FIFO
tasks at equal priority shared the CPU, taskA migrate_disable()'d and
queued, taskB as rq->curr. In one 89 ms window, taskB got only 52 ms of
CPU. The other 37 ms went to the stopper thread.
The scheduler kept trying to push taskA, the pinned head of the pushable
list, fell back to pushing taskB instead, and woke the stopper 5204
times. Every one of those pushes failed and no task was moved. taskA
stayed runnable and queued the whole time, and never ran.
Pushing taskB fails on a re-check. find_lock_lowest_rq() drops the rq
lock to take the target rq lock, then checks again with
"task != pick_next_pushable_task(rq)".
The task being pushed is taskB, but the pick returns taskA, the head of
the pushable list. taskB is rq->curr, and set_next_task_rt() removes the
running task from that list, so taskB can never be the head. The check
expects a candidate taken from the pushable list, but the fallback
pushes rq->curr, which is never on that list. So the check fails every
time.
.--> push-IPI arrives
| |
| v
| pushable head = taskA -> pinned, cannot be pushed
| |
| v
| so push taskB instead -> wake migration/N, a stop-class
| | thread, so it preempts taskB
| v
| re-check compares taskB against the pushable head,
| which is still taskA -> give up
| |
| v
| nothing moved, taskA still queued, rq still overloaded
| |
'----------'
repeats every ~17 us, 5204 times, for 89 ms
The loop cannot stop itself. Every round leaves the runqueue
exactly as it was, so the next push-IPI does the same thing. In
the capture it ended only when taskB went to sleep on its own.
taskA was then picked locally and left the pushable list.
CPU time per task in the window, from sched_switch:
taskB 51.95 ms real work
migration/N 37.18 ms nothing moved
taskA 0.00 ms queued the whole time, never picked
idle 0.01 ms
Counts over the same window:
7667 push-IPIs handled on this CPU
17481 pick_next_pushable_task() returned taskA, still pinned
5204 find_lock_lowest_rq() gave up on the re-check
1 push that actually completed
0 migrations of taskA
The CPU times and the window length come from the standard
sched_switch tracepoint. The counts needed tracepoints added inside
the RT balancer for this investigation.
The self-IPI path is closed by the rto_next_cpu() fix above, and that
part works. But the runqueue is still marked overloaded, because the
pinned task is still advertised as pushable. Other CPUs now send the
push-IPIs during their own RT balancing, and the same loop runs again.
Closing the self-IPI path did not stop a pinn
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: ump: do not touch legacy_rmidi before it exists
snd_ump_parse_endpoint() sets ump->parsed on every exit, including
error, before the caller attaches the legacy rawmidi device.
ump_handle_ep_name_msg() then treats parsed as "legacy_rmidi is live"
and calls ump_legacy_set_rawmidi_name(), which snprintf()s into
ump->legacy_rmidi->name. If a UMP packet arrives in that window
(IRQ path from snd_ump_receive), legacy_rmidi is still NULL
(KASAN null-ptr-deref in snprintf).
Guard the legacy helpers. parsed only means endpoint info was
parsed, not that legacy_rmidi exists. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: backtrack_insn(): Handle ld_{abs,ind} subprog exit edge
Nicholas Carlini reported a bug in precision backtracking mechanism
for BPF_LD | BPF_{IND,ABS} instructions. These instructions are
modelled as two branches:
- fallthrough;
- implicit exit from current subprogram.
The implicit exit case was not handled by the backtrack_insn()
function. When backtracking such a path backtrack_insn() did not
call bt_subprog_enter(), which meant that backtracking continued
manipulating precision marks in a caller frame, while looking at
instructions in a callee frame.
This lead to segmentation faults during verification (see the
selftest), or unsound state pruning. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: backtracking shouldn't clear outer frame R1-R5 for callbacks
When processing calls to bpf_loop() verifier marks R1 (and R4) as
precise. R1 tracks loop iterations number and because of the
'callback_depth < R1' mechanics in check_helper_call() must be marked
precise. However, precision propagation for R1 was broken,
when bpf_loop() call was verified on a second iteration.
Consider the following verification trace:
- main: bpf_loop(nr_loops, callback ...)
- callback: BPF_EXIT
- main: bpf_loop(nr_loops, callback ...)
- ...
While the first visit of the call to bpf_loop() propagated R1
precision as expected, the second call to mark_chain_precision() in
the check_helper_call() set R1, but it was immediately reset when
backtrack_insn() processed preceding BPF_EXIT in the loop deleted in
this patch.
Because of that, the second visit of the call to bpf_loop() injected
checkpoint with R1 not marked as precise. Which could trick the
verifier into accepting unsafe programs. See the next patch for an
example of such program.
Commit is structured in a way to minimize conflicts when
'bpf' would be eventually merged with 'bpf-next'. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix transaction use-after-free in raid stripe insertion
If allocation of a RAID stripe extent fails,
btrfs_insert_one_raid_extent() aborts and ends the transaction before
returning -ENOMEM.
btrfs_finish_one_ordered(), the production caller through
btrfs_insert_raid_extent(), still owns the transaction handle. It handles
the error by aborting the transaction and then reaches the common exit
path, which ends the transaction again.
The premature end can free the handle and drop its transaction reference.
Transaction cleanup can then free the transaction before the caller's
second abort accesses the handle and transaction, resulting in
use-after-free.
Keep the abort at the failure site, but let the caller's common exit path
end the transaction once, after it has finished using both objects. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix the possible bioc_list memory leak during error
There are two possible ways to leak bioc memory on
btrfs_ordered_extent::bioc_list:
- An error occurred for btrfs_insert_one_raid_extent()
Then the function btrfs_insert_raid_extent() immediately return
without freeing any bioc in the bioc_list.
- An ordered extent hit an IO error
In that case the ordered extent will have BTRFS_ORDERED_IOERR set, and
skip the call on btrfs_insert_raid_extent() completely.
Fix the problem by:
- Introduce a new helper, btrfs_cleanup_ordered_bioc_list()
Which will remove all bioc from the bioc_list, and release the bioc.
- Call the above helper for btrfs_insert_raid_extent()
So that the cleanup helper is always called no matter what.
- Call the above helper for btrfs_finish_one_ordered()
This is called just before the final release on the ordered extent.
This was reported by Sashiko when reviewing another patch. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: zoned: finish active block group cleanup if call_zone_finish() fails
do_zone_finish() clears BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE before finishing
the zones. If call_zone_finish() then fails it returned early, leaving the
now inactive block group on fs_info->zone_active_bgs, leaking its
reference, the BTRFS_FS_NEED_ZONE_FINISH waiters are never woken, and as
its alloc_offset equals the zone capacity btrfs_zone_finish_one_bg() keeps
selecting it, spinning btrfs_zoned_activate_one_bg().
Fall through to the cleanup on failure too and return the error, but keep
the block group read-only as its zones are left inconsistent. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: do not force reloc root creation during qgroup_account_snapshot()
[BUG]
When running btrfs/252 with quota enabled through MKFS_OPTIONS="-O quota",
it has a high chance to trigger the following kernel warning and flips
the fs RO:
BTRFS info (device dm-2): relocating block group 30408704 flags metadata|dup
------------[ cut here ]------------
WARNING: fs/btrfs/extent-tree.c:879 at lookup_inline_extent_backref+0x74b/0x960 [btrfs], CPU#4: btrfs/2173
CPU: 4 UID: 0 PID: 2173 Comm: btrfs Not tainted 7.2.0-rc6-custom+ #457 PREEMPT(full) 3adc6528fb66f7a55fe1095385818e742f200aab
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022
RIP: 0010:lookup_inline_extent_backref+0x74b/0x960 [btrfs]
Call Trace:
<TASK>
insert_inline_extent_backref+0x7c/0x160 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72]
__btrfs_inc_extent_ref+0xa9/0x270 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72]
__btrfs_run_delayed_refs+0x4af/0x11c0 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72]
btrfs_run_delayed_refs+0x9d/0xf0 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72]
create_pending_snapshot+0x39d/0xf00 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72]
create_pending_snapshots+0x9b/0xc0 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72]
btrfs_commit_transaction+0x280/0xeb0 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72]
prepare_to_relocate+0x147/0x200 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72]
relocate_block_group+0x6b/0x5e0 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72]
btrfs_relocate_block_group+0x92c/0x2380 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72]
btrfs_relocate_chunk+0x3f/0x1a0 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72]
btrfs_balance+0xa2c/0x19c0 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72]
btrfs_ioctl+0x2839/0x2d30 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72]
__x64_sys_ioctl+0x416/0x9a0
do_syscall_64+0xe1/0x790
entry_SYSCALL_64_after_hwframe+0x4b/0x53
</TASK>
---[ end trace 0000000000000000 ]---
BTRFS info (device dm-2): leaf 4593991680 gen 233 total ptrs 175 free space 5953 owner 2
BTRFS info (device dm-2): refs 3 lock_owner 2173 current 2173
item 0 key (166772736 METADATA_ITEM 1) itemoff 16250 itemsize 33
extent refs 1 gen 222 flags 2
ref#0: tree block backref root 266
[ Skip the tree dump ]
item 174 key (263225344 METADATA_ITEM 0) itemoff 10328 itemsize 33
extent refs 1 gen 162 flags 258
ref#0: tree block backref root 267
BTRFS error (device dm-2): extent item not found for insert, bytenr 179847168 num_bytes 16384 parent 4594335744 root_objectid 273 owner 0 offset 0
BTRFS error (device dm-2): failed to run delayed ref for logical 179847168 num_bytes 16384 type 182 action 1 ref_mod 1: -117
[CAUSE]
The above error is showing that there is a tree reference to a metadata
extent that is no longer there.
With "ref_verify" mount option (requires CONFIG_BTRFS_DEBUG), there is
some extra debug output:
BTRFS error (device dm-2): dumping block entry [180961280 16384], num_refs 0, metadata 1, from disk 0
BTRFS error (device dm-2): root entry 256, num_refs 18446744073709551615
BTRFS error (device dm-2): root entry 273, num_refs 18446744073709551615
BTRFS error (device dm-2): Ref action 3, root 273, ref_root 273, parent 0, owner 0, offset 0, num_refs 1
btrfs_force_cow_block+0x129/0x7d0 [btrfs]
btrfs_cow_block+0x10a/0x250 [btrfs]
btrfs_search_slot+0x5eb/0xf40 [btrfs]
btrfs_insert_empty_items+0x3a/0x70 [btrfs]
insert_with_overflow+0x53/0x130 [btrfs]
btrfs_insert_dir_item+0x125/0x290 [btrfs]
btrfs_add_link+0xaa/0x410 [btrfs]
btrfs_rename+0x5ea/0xcd0 [btrfs]
btrfs_rename2+0x28/0x60 [btrfs]
vfs_rename+0x5b2/0xe10
filename_renameat2+0x244/0x430
__x64_sys_rename+0x48/0x70
do_syscall_64+0xe1/0x790
entry_SYSCALL_64_after_hwframe+0x4b/0x53
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: zstd: fix lost wakeup when waiting for a workspace
A writer can sleep forever in zstd_get_workspace() even though a workspace
is free. When zstd_alloc_workspace() fails, the task is queued on
zwsm->wait and schedules unconditionally, never re-testing the pool.
zstd_put_workspace() publishes the workspace and then calls cond_wake_up(),
which only wakes when a sleeper is already visible, so a workspace returned
between the failed allocation and prepare_to_wait() wakes nobody. The
window is wide: zstd_alloc_workspace() goes through kvmalloc() and may
enter reclaim.
Only a max level workspace triggers the wakeup and one is deliberately kept
allocated as the fallback every waiter waits for, so once its wakeup is
lost the writer stays in TASK_UNINTERRUPTIBLE until some other task happens
to return one. Re-check the pool after prepare_to_wait() has published the
waiter, and use the workspace if one turned up. |
| In the Linux kernel, the following vulnerability has been resolved:
ipvs: fix reversed sequence option serialization
hton_seq() expects the host-order source first and the unaligned
network-order destination second. The version 1 sync sender passes these
arguments in reverse for both sequence blocks. This leaves 24 bytes of the
kmalloc-backed message unwritten. It may disclose stale heap data and
replace the live connection sequence state with values read from the
buffer.
Pass the connection sequence state as the source and the message payload as
the destination for both blocks. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_conntrack_sip: fix OOB read in sip_skip_whitespace()
sip_skip_whitespace() returns dptr unchanged when its own loop
exhausts the buffer (dptr == limit), instead of NULL like its sibling
sip_follow_continuation() returns on its own "no more data" path.
ct_sip_get_header() only checks for NULL after calling it:
dptr = sip_skip_whitespace(dptr, limit);
if (dptr == NULL)
break;
if (*dptr != ':' || ++dptr >= limit)
break;
so a recognized header name followed only by spaces/tabs running to
the exact end of the SIP payload, with no colon, makes the very next
statement read one byte past the buffer.
Make both "no more data" outcomes return NULL, matching the
convention sip_follow_continuation() already uses and that both
existing callers already check for. |
| In the Linux kernel, the following vulnerability has been resolved:
tracing/probes: Fix use-after-free on field name/type of events with multiple probes
The fields of a probe-based dynamic event (kprobe, uprobe, eprobe and
fprobe events) are created in traceprobe_define_arg_fields() by handing
the probe_arg name/type strings to trace_define_field(), which only
stores the pointers without copying. Those strings are owned by the
trace_probe and are freed when that probe is removed.
An event can have several probes attached. The field list is defined
only once, by the first probe that registers the event, but it is kept
alive by any surviving sibling probe. Deleting just that first probe by
symbol -
# primary A: fields are defined from A's args
echo 'p:kprobes/ev vfs_read a1=$arg1' > kprobe_events
# append B: shares A's event call
echo 'p:kprobes/ev vfs_write a1=$arg1' >> kprobe_events
# delete only A (matched by symbol), B survives
echo '-:kprobes/ev vfs_read' >> kprobe_events
frees A's args (trace_probe_cleanup() -> traceprobe_free_probe_arg()),
but trace_probe_unlink() keeps the trace_probe_event because the probe
list is not empty. The event call stays registered via B while its
fields now reference freed memory. Any field lookup then reads it, e.g.
echo 'a1 == 1' > events/kprobes/ev/filter
BUG: KASAN: slab-use-after-free in strcmp+0xa7/0xb0
Call Trace:
strcmp
trace_find_event_field
parse_pred
process_preds
create_filter
apply_event_filter
event_filter_write
field->name references parg->name (kstrdup'd, freed with the probe) and,
for array arguments, field->type references parg->fmt (kmalloc'd, freed
with the probe) - the scalar type otherwise points at the static
fmttype rodata, which is safe.
Have traceprobe_define_arg_fields() duplicate the name and type strings
and anchor the copies on the trace_probe_event, which embeds the event
call and outlives every individual probe; trace_probe_event_free()
releases them.
The reproducer above triggers reliably; the field lookup and the delete
both run under event_mutex, so this is a dangling reference after
removal rather than a race.
The issue was found by the autokbug dynamic kernel fuzzer at Tencent
Yunding Lab. |
