| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix NULL-ptr-deref when showing a void BTF type
btf_modifier_show() resolves the modifier and then calls
btf_type_ops(t)->show() unconditionally. For the void type (type_id 0,
BTF_KIND_UNKN) kind_ops[] has no entry, so ->show is NULL.
A "const void" (a modifier resolving to void) cannot be a map key or
value - map_check_btf() rejects it because void has no size - so the map
dump path does not reach it. But bpf_snprintf_btf() takes a type_id
straight from the BPF program, and passing such a "const void" from the
vmlinux BTF NULL-derefs:
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
RIP: 0010:btf_modifier_show (kernel/bpf/btf.c:2914)
Call Trace:
<TASK>
btf_type_show (kernel/bpf/btf.c:8251)
btf_type_snprintf_show (kernel/bpf/btf.c:8321)
bpf_snprintf_btf (kernel/trace/bpf_trace.c:1047)
bpf_prog_test_run_raw_tp (net/bpf/test_run.c:829)
__sys_bpf (kernel/bpf/syscall.c:4804)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
</TASK>
Fall back to btf_df_show() when the resolved type has no show op; it
emits the "<unsupported kind:N>" placeholder already used for kinds like
FWD and FUNC. bpf_snprintf_btf() then returns the length as usual. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Reject key-less BTF for hash maps
map_check_btf() allows a key-less BTF (btf_key_type_id == 0) only for
maps that have a ->map_check_btf callback, and leaves the actual
decision to that callback. Hash maps used to have no ->map_check_btf,
so a key-less BTF was rejected outright.
That changed when htab and rhtab gained a ->map_check_btf to register a
dtor - htab in commit 1df97a7453ee ("bpf: Register dtor for freeing
special fields") and rhtab in commit 6905f8601298 ("bpf: Allow special
fields in resizable hashtab"). Neither looks at the key, so a key-less
hash map now passes map_check_btf() and gets created. Reading it back
through bpffs feeds the key type_id 0 into btf_type_seq_show();
btf_type_by_id() returns the void type, kind_ops[BTF_KIND_UNKN] is NULL,
and btf_type_show() dereferences it:
RIP: 0010:btf_type_show+0x223/0x2e0 kernel/bpf/btf.c:8232
RSP: 0018:ffffc9000399f868 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000028
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: ffffc9000399f970 R11: 0000000000000001 R12: ffffffff9b96b140
R13: ffffc9000399f8e0 R14: ffff88803d393c00 R15: 0000000000000003
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000000 CR3: 000000003d213000 CR4: 0000000000352ef0
DR0: 0000000039ae8f55 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
btf_type_seq_show_flags+0xca/0x120 kernel/bpf/btf.c:8250
htab_map_seq_show_elem+0x12e/0x350 kernel/bpf/hashtab.c:1669
map_seq_show+0x13d/0x1e0 kernel/bpf/inode.c:293
traverse.part.0.constprop.0+0x107/0x650 fs/seq_file.c:112
traverse fs/seq_file.c:99 [inline]
seq_read_iter+0x93f/0x1270 fs/seq_file.c:196
seq_read+0x344/0x4d0 fs/seq_file.c:163
vfs_read+0x1e4/0xb40 fs/read_write.c:572
ksys_pread64 fs/read_write.c:764 [inline]
__do_sys_pread64 fs/read_write.c:772 [inline]
__se_sys_pread64 fs/read_write.c:769 [inline]
__x64_sys_pread64+0x1eb/0x250 fs/read_write.c:769
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Reject a key-less BTF in htab_map_check_btf() and rhtab_map_check_btf(),
restoring the previous behavior. |
| In the Linux kernel, the following vulnerability has been resolved:
erofs: disable LZ4 rolling decompression for now
LZ4 rolling decompression [1] was introduced to reduce the memory
footprint of temporary pages:
For many cases, it is needed for users to read small data within
a compressed extent (pcluster), either due to random small read, or
since uptodate folios (typically order-0) cannot be reused for
decompression again since decompression algorithm refills
already-uptodate folios.
Rolling decompression works because LZ4 is LZ77-based and only refers
to the most recent 64 KiB of decompressed data, so in theory only a
bounded rolling window of temporary pages is needed when decompressing.
It can save a lot of temporary memory, e.g.
601,960-byte data can be compressed into a 256k LZ4 compressed extent,
which means it needs 146 extra pages per request in the worst case if
rolling decompression is disabled.
However, the upstream LZ4 implementation is not under EROFS' control:
For example, the literal copy memmove() may still **copy long literals
backward** on x86 based on the address comparison even when the source
and destination ranges do not overlap (IOWs, inline decompression
doesn't need to be considered here). That breaks the rolling assumption
and makes the optimization broken.
Disable it for now to make sure the data correctness first since EROFS
is used everywhere now: The rolling window approach can be revived once
we either ensure that the official LZ4 code always copies forward for
non-overlapping ranges or maintain our own LZ4 implementation in EROFS.
The main impact is a higher runtime memory footprint; However, recent
commit 0f6273ab4637 ("erofs: add a reserved buffer pool for lz4
decompression") helps mitigate this when enabled but it's still not
perfect.
[1] https://www.usenix.org/conference/atc19/presentation/gao
ยง 3.3 Decompression |
| In the Linux kernel, the following vulnerability has been resolved:
net/rds: don't let rds_conn_shutdown() consume a concurrent drop
rds_conn_shutdown() finishes by moving the path from
RDS_CONN_DISCONNECTING to RDS_CONN_DOWN, and also accepts
RDS_CONN_ERROR as the starting state of that final transition, so that
a FIN processed in softirq context during the teardown does not derail
the shutdown into a noisy error path.
But consuming that RDS_CONN_ERROR also consumes the shutdown pass that
came with it: rds_conn_path_drop() sets RDS_CONN_ERROR and then queues
cp_down_w, and a pass that starts on a path already in RDS_CONN_DOWN
is a no-op. For the FIN case that is harmless - the socket the FIN
arrived on is the very socket the teardown just released. It is not
harmless for a dropper that attached something to the path first.
rds_tcp_accept_one() is such a dropper. Its path claim in
rds_tcp_accept_one_path() transitions RDS_CONN_DOWN ->
RDS_CONN_CONNECTING, and a concurrent drop - a FIN on a previous
socket in softirq context, an administrative reset - can put the path
into RDS_CONN_ERROR between that claim and the state check that
follows, which accepts RDS_CONN_ERROR. The accept then installs the
freshly accepted socket with rds_tcp_set_callbacks() while the queued
teardown - which sampled tc->t_sock before this socket existed - is
still running. rds_connect_path_complete() fails its transition to
RDS_CONN_UP and drops the path again, queueing the pass that should
reap the socket it just installed. If the in-flight shutdown's final
transition consumes that drop's RDS_CONN_ERROR, the queued pass finds
the path in RDS_CONN_DOWN and does nothing. The installed socket is
never torn down: it sits established with its callbacks armed and its
rds_tcp_connection on rds_tcp_tc_list, the peer sees a connection that
nothing ever reads, and the path is wedged in RDS_CONN_DOWN until some
later event drops it again. Reproduced with widened race windows as
an ever-growing receive queue on a socket owned by a path stuck in
RDS_CONN_DOWN, with the peer's send path wedged behind it.
Make the final transition only DISCONNECTING -> DOWN. If it fails
because the path is in RDS_CONN_ERROR, a drop raced the teardown:
cancel the reconnect timer and clear RDS_RECONNECT_PENDING - the one
piece of the skipped tail that must not be left behind - and return,
letting the pass the drop queued finish the job: it tears down
whatever attached to the path in the meantime, completes the
transition to RDS_CONN_DOWN, and re-arms the reconnect from its own
tail.
The timer quiesce in that branch matters because the racing drop does
not always queue that pass: rds_conn_path_drop() returns without
queueing when a destroy is pending - exactly the situation during a
netns teardown or module unload, when a FIN on the dying socket is
processed while rds_conn_path_destroy() flushes cp_down_w. If the
flushed pass is the one that takes this return, no later pass exists,
and rds_conn_path_destroy() would find cp_conn_w still armed
(WARN_ON) and then free a path whose reconnect timer can still fire.
With the cancel in the branch, every exit of a shutdown pass leaves
the timer quiesced no matter which pass completes the transition.
The FIN case keeps making progress, one pass later and still without
noisy logging. Any other state keeps today's rds_conn_path_error()
handling; no current cp_state writer can leave a DISCONNECTING path
in anything but RDS_CONN_ERROR (every other writer is a cmpxchg from
a non-DISCONNECTING state), so that branch is defensive.
On kernels without the preceding patches the same hazard exists with
the sample-based quiesce; the fix applies there equally. |
| In the Linux kernel, the following vulnerability has been resolved:
net/rds: acquire RDS_IN_XMIT in rds_tcp_reset_callbacks()
rds_tcp_reset_callbacks() quiesces the transmit path by setting the
path state to RDS_CONN_RESETTING and then waiting for RDS_IN_XMIT to
be sampled clear before swapping the underlying socket and calling
rds_send_path_reset().
Sampling the bit clear is not the same as owning it: rds_send_xmit()
can re-acquire RDS_IN_XMIT right after the wait_event() returns. Its
state recheck after taking the lock is a store-buffering pattern (the
resetter writes the state and reads the bit, the sender writes the
bit and reads the state) and acquire_in_xmit() is only an acquire
operation, so on weakly ordered architectures both sides can miss
each other's write and the transmit path then runs concurrently with
rds_send_path_reset() rewriting cp_xmit_* state - which is exactly
what the comment above rds_send_path_reset() tells its callers to
prevent.
Take the lock instead, hold it across the socket swap and
rds_send_path_reset(), and release it with a wake-up at the end. The
lock-ordering constraint documented above the wait still holds: the
lock is acquired before lock_sock(), so a sender inside tcp_sendmsg()
can never be waited on while we hold the socket lock.
Two details of the old code go away with the same change:
- t_sock is now read only after the lock is acquired. The old code
cached it before waiting; the teardown in rds_conn_shutdown()
releases that socket and clears t_sock, so a pointer cached before
the wait can be stale by the time the accept path resumes. Reading
it under RDS_IN_XMIT is what makes the exclusion complete once the
teardown owns the same lock, which the next patch arranges; until
then the teardown still only samples the bit, and the two paths
remain as exposed to each other as they are today.
- The old !osock early path called rds_send_path_reset() with no
serialization at all. It now runs under the lock like the normal
path. The conditional RDS_CONN_RESETTING transition of the
previous patch happens before the socket check either way: a path
found without a socket is either still connecting (its reconnect
worker blocked on t_conn_path_lock) and legitimately goes
RESETTING -> UP on the new socket, or it has been torn down
meanwhile and is dropped.
The in-function comment describing the old wait-based quiesce is
rewritten to describe the lock-based one, and the stale block comment
above the function (which still described a return value and an
incomplete list of t_sock writers) is refreshed to name all four
writers - the connect, accept, teardown and swap paths - and what
serializes each of them. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: reject BPF_PSEUDO_FUNC reference to the main program
fixups.c:jit_subprogs() rewrites BPF_PSEUDO_FUNC loads to contain real
function addresses. This function is invoked from bpf_jit_subprogs()
only when env->subprog_cnt > 1. Meaning that for any program like
below:
int main(void *ctx) {
void *ptr = main;
...
bpf_timer_set_callback(..., ptr);
...
}
The 'ptr' won't be ever converted to contain an address.
In combination with e.g. bpf_timer_set_callback() this would lead to a
function call at a bogus address.
Instead of complicating the implementation, just assume that no useful
program needs main to be a sync or async callback and reject
BPF_PSEUDO_FUNC loads for the main subprogram. |
| 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. |
| 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:
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--- |
| Piwigo is a full featured open source photo gallery application for the web. Prior to 16.4.0, admin/batch_manager.php accepts administrator-controlled dimension width, height, and ratio values and filesize values from the Batch Manager filter URL without numeric validation. The URL filter parser stores those values in the bulk_manager_filter session state, and later query construction concatenates them into SQL predicates, unlike the validated POST filter path. An authenticated administrator can use crafted filter values to execute time-based or other SQL expressions and potentially disclose, modify, or disrupt database data. This issue is fixed in version 16.4.0. |
| PostgreSQL Anonymizer contains a vulnerability that allows unprivileged masked users to repeatedly call the anon.hash() function and collects (seed, hash_output) pairs to perform an offline brute-force attack and deduce the salt. A masked role can run a RESTRICTED function when the call is placed inside the sub-select. The problem is resolved in PostgreSQL Anonymizer 3.2.3 and later versions |
| InvoicePlane is a self-hosted open source application for managing invoices, clients, and payments. Prior to 1.7.2, InvoicePlane exposes Invoices::delete() and Invoices::delete_invoice_tax() as state-changing routes without requiring POST and validating a CSRF token. When an authenticated administrator loads attacker-controlled content that requests an affected route, the application can delete an invoice or invoice tax record. The cross-origin action can remove financial data without the administrator's intent. This issue is fixed in version 1.7.2. |
| InvoicePlane is a self-hosted open source application for managing invoices, clients, and payments. Prior to 1.7.2, InvoicePlane's Invoices::generate_xml() method appends a database-derived xml_id to the XMLconfigs helper directory and includes the resulting PHP path without validating the identifier. A low-privileged attacker who can influence the e-invoice configuration can use traversal sequences to include an existing PHP file. The standalone advisory establishes local file inclusion; code execution requires a separate file-upload or file-write primitive. This issue is fixed in version 1.7.2. |
| InvoicePlane is a self-hosted open source application for managing invoices, clients, and payments. Prior to 1.7.2, InvoicePlane interpolates the administrator-controlled tax_rate_decimal_places setting into an ALTER TABLE statement for ip_tax_rates in Settings::index() without strict integer validation. A crafted setting value can add clauses to the schema-changing statement and remove or alter required database columns. The resulting schema corruption can permanently modify financial data structures and make the application unavailable. This vulnerability is fixed in 1.7.2. |
| An issue in MongoDB Server's query execution engine could allow an authenticated user with read and write privileges to cause an internal reference to be used after the underlying memory has been freed, when running certain queries against time-series collections. This could result in a server crash or disclosure of freed memory contents within query results. |
| Input Leap (aka input-leap) through 3.0.3, when the non-default --enable-drag-drop option is used on Windows or macOS, mishandles the / versus \ distinction and allows directory traversal, with resultant code execution if a file is written to a startup directory. This occurs via a DDRG message. |
| InvoicePlane is a self-hosted open source application for managing invoices, clients, and payments. Prior to 1.7.2-rc-1, InvoicePlane builds its permitted template list by scanning a PHP template directory that can be written through an administrator-controlled file-write capability. A malicious PHP file placed in the directory is automatically trusted by Mdl_templates and can be selected as public_invoice_template. When a public invoice is rendered, the guest View controller includes the trusted file and executes it with web-server privileges. This issue is fixed in version 1.7.2-rc-1. |
| In the Linux kernel, the following vulnerability has been resolved:
vhost-vdpa: protect config_ctx from being freed under the config callback
vhost_vdpa_config_cb() loads v->config_ctx and signals it without taking
a reference and without holding any lock:
struct eventfd_ctx *config_ctx = v->config_ctx;
if (config_ctx)
eventfd_signal(config_ctx);
VHOST_VDPA_SET_CONFIG_CALL replaces that field and drops what is normally
the last reference to the old context:
swap(ctx, v->config_ctx);
if (ctx)
eventfd_ctx_put(ctx);
eventfd_ctx_put() drops the last kref and frees the context immediately,
with no RCU grace period, so a callback that has already loaded the
pointer goes on to dereference freed memory. The two sides share no
lock: the ioctl runs under vhost_dev.mutex, while the parent invokes the
callback from its own interrupt or workqueue context.
This is not the reopen refcount underflow fixed by commit f6bbf0010ba0
("vhost-vdpa: fix use-after-free of v->config_ctx"), which was about
vhost_vdpa_config_put() leaving a stale pointer behind. Here the pointer
is maintained correctly and it is the read side that is unprotected.
With VDUSE as the parent this is reachable from userspace with access to
/dev/vduse (root by default). VDUSE_DEV_INJECT_CONFIG_IRQ queues
dev->inject, and vduse_dev_irq_inject() runs the callback under VDUSE's
own dev->irq_lock, which vhost does not hold. vduse_dev_reset() does
flush_work(&dev->inject), but VHOST_VDPA_SET_CONFIG_CALL never goes
through reset, so an inject already in flight is not waited for. A
process that injects config interrupts on the VDUSE fd while another
thread swaps the call fd on the vhost-vdpa fd hits it in seconds:
BUG: KASAN: slab-use-after-free in native_queued_spin_lock_slowpath
Read of size 4 at addr ffff888107d21808 by task kworker/u17:1/2993
Workqueue: vduse-irq vduse_dev_irq_inject
Call Trace:
native_queued_spin_lock_slowpath+0x97/0x5b0
_raw_spin_lock_irqsave+0xd4/0xe0
eventfd_signal_mask+0x69/0x120
vhost_vdpa_config_cb+0x34/0x50
vduse_dev_irq_inject+0x46/0x60
process_one_work+0x468/0x950
Allocated by task 2992:
do_eventfd+0x50/0x200
__x64_sys_eventfd2+0x2e/0x40
Freed by task 2992:
eventfd_ctx_put+0xb9/0xc0
vhost_vdpa_unlocked_ioctl+0x116c/0x2190
Add a spinlock covering every access to config_ctx, so the callback
either signals a context that is still alive or observes NULL, and the
put happens only once no callback can reach the old value.
Clearing the parent's callback before the put would not be enough: of the
in-tree set_config_cb() implementations only VDUSE takes a lock, the rest
store the pointer unlocked, so that would not order against an in-flight
invocation. |
| In the Linux kernel, the following vulnerability has been resolved:
vhost-vdpa: don't install the eventfd_ctx_fdget() error in config_ctx
vhost_vdpa_set_config_call() swaps the eventfd_ctx_fdget() return value
into v->config_ctx before checking it, so on failure the field briefly
holds an ERR_PTR:
ctx = fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(fd);
swap(ctx, v->config_ctx);
if (!IS_ERR_OR_NULL(ctx))
eventfd_ctx_put(ctx);
if (IS_ERR(v->config_ctx)) {
long ret = PTR_ERR(v->config_ctx);
v->config_ctx = NULL;
return ret;
}
Commit 0bde59c1723a ("vhost-vdpa: set v->config_ctx to NULL if
eventfd_ctx_fdget() fails") added that clearing, and spelled out the
invariant the rest of the file relies on: "we consider 'v->config_ctx'
valid if it is not NULL". The window between the swap and the clearing
still breaks it. vhost_vdpa_config_cb() only tests for NULL, so a config
interrupt delivered inside the window hands the ERR_PTR to
eventfd_signal().
Check the fd before installing it instead. That closes the window and
matches how vhost_vring_ioctl() handles the same failure for the vq call
fd.
It also stops a rejected fd from tearing down a config interrupt that was
working: until now the swap replaced the live context and put it, so
after an EBADF the device silently stopped delivering config interrupts
until userspace installed a new fd. |
| In the Linux kernel, the following vulnerability has been resolved:
virtio: fix use-after-free in unregister_virtio_device()
device_unregister() is device_del() plus put_device(). When the caller
holds no extra reference, that drops the last one and runs the release
callback, which for several transports frees the memory the embedded
struct virtio_device sits in. unregister_virtio_device() then calls
virtio_debug_device_exit(), which reads dev->debugfs_dir out of the freed
object.
Affected transports are the ones whose release callback frees and whose
remove path takes no reference: virtio_mmio, virtio_vdpa, virtio_uml,
mlxbf-tmfifo and virtio_ccw. virtio_pci is unaffected because
virtio_pci_remove() brackets the call with get_device() and put_device().
Remove the debugfs entries before the device can go away. They are only
accessed through the protected debugfs interface, so
debugfs_remove_recursive() waits for in-progress file operations before
returning. Tearing them down while the device is still alive is therefore
safe.
Reproduced on User-Mode Linux with CONFIG_KASAN and CONFIG_VIRTIO_DEBUG
by unbinding a virtio-uml device:
BUG: KASAN: slab-use-after-free in virtio_debug_device_exit+0x36/0x4d
Read of size 8 at addr 00000000616e0b10 by task init/1
__asan_report_load8_noabort
virtio_debug_device_exit+0x36/0x4d
unregister_virtio_device+0x48/0x75
virtio_uml_remove
platform_remove
device_release_driver_internal
unbind_store
Freed by task 1:
kfree
virtio_uml_release_dev
device_release
kobject_put
put_device
device_unregister
With this applied, the report is gone and unbind is clean. |
