| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| Race condition in USB in Google Chrome prior to 151.0.7922.169 allowed a remote attacker who had compromised the renderer process to potentially execute arbitrary code outside the sandbox via a crafted HTML page. (Chromium security severity: High) |
| A flaw was found in Keycloak. An authenticated administrator with the `manage-clients` role can exploit a Time-of-check to time-of-use (TOCTOU) vulnerability in the name-based admin role checks. This allows the attacker to escalate their privileges to `realm-admin` for all users within the realm, granting them extensive control over the system. The composite role relationship persists even after the attacker's own permissions are revoked and across system reboots. |
| Lemur manages TLS certificate creation. Prior to 1.9.3, _validate_revocation_url in lemur/certificates/verify.py checked the original CRL or OCSP URL but the later request could reach a different destination. The CRL requests.get call followed HTTP redirects without validating each Location target, so a public attacker-controlled URL could redirect to loopback, RFC1918, link-local, or instance-metadata addresses. Validation and connection also performed separate DNS resolutions, creating a time-of-check time-of-use window for DNS rebinding on both CRL and OCSP paths. An operator uploading a certificate through POST /api/1/certificates/upload could therefore induce blind internal requests despite the earlier mitigation. The fix disables redirects and pins validated addresses while preserving the correct Host value. This issue is fixed in version 1.9.3. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_conncount: prevent connlimit drops for early confirmed ct
Commit 69894e5b4c5e ("netfilter: nft_connlimit: update the count if add
was skipped") introduced a regression where packets for valid
connections are dropped when using connlimit for soft-limiting
scenarios.
The issue occurs when a new connection reuses a socket currently in
the TIME_WAIT state. In this scenario, the connection tracking entry
is evaluated as already confirmed. Previously, __nf_conncount_add()
assumed that if a connection was confirmed and did not originate from
the loopback interface, it should skip the addition and return -EEXIST.
Skipping the addition triggers a garbage collection run that cleans up
the TIME_WAIT connection. Consequently, the active connection count
drops to 0, which xt_connlimit mishandles, leading to the false rejection
of the perfectly valid new connection.
Fix this by replacing the interface check with protocol-agnostic state
checks. We now skip the tree insertion and preserve the lockless garbage
collection optimization only if the connection is IPS_ASSURED. This
allows early-confirmed setup packets (such as reused TIME_WAIT sockets
or locally generated SYN-ACKs) to be properly evaluated and counted
without falsely dropping. The goto check_connections path is maintained
to ensure these setup packets are deduplicated correctly.
This has been tested with slowhttptest and HTTP server configured
locally to ensure we are not breaking soft-limiting scenarios for local
or external connections. In addition, it was tested with a OVS zone
limit too. |
| n8n is an open source workflow automation platform. Prior to 1.123.64, 2.29.8, and 2.30.1, the Git node clone operation allows an authenticated workflow user to swap a validated directory for a symlink before cloning, planting a crafted repository in the community node directory that loads as a custom JavaScript node after restart and executes arbitrary code on the server. This issue is fixed in versions 1.123.64, 2.29.8, and 2.30.1. |
| In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix use-after-free of conn->preauth_info in concurrent SMB2 NEGOTIATE
conn->preauth_info is shared connection state (struct
preauth_integrity_info, kmalloc-96) that is allocated and freed by the
SMB2 NEGOTIATE handler and read by the response send path.
smb2_handle_negotiate() allocates conn->preauth_info, and on a
deassemble_neg_contexts() failure kfrees it and sets it to NULL. Both the
allocation and the free/NULL happen under ksmbd_conn_lock(conn) (the
connection srv_mutex), which is held across the whole handler body.
The response send path smb3_preauth_hash_rsp(), called from the send:
block of __handle_ksmbd_work(), reads conn->preauth_info and dereferences
conn->preauth_info->Preauth_HashValue (via
ksmbd_gen_preauth_integrity_hash()) without taking conn_lock. When a
client drives two SMB2 NEGOTIATE requests on the same connection, one
worker can free conn->preauth_info on the failing-negotiate path while a
concurrent send-path worker is reading it, producing a slab
use-after-free read (KASAN-confirmed).
The send-path read tested conn->preauth_info for NULL but raced with the
free that occurs between the NULL check and the dereference, so the NULL
guard alone does not close the window.
Serialize the NEGOTIATE-branch read in smb3_preauth_hash_rsp() under
ksmbd_conn_lock(conn) and re-check conn->preauth_info inside the lock.
Because the negotiate handler holds conn_lock across its kfree + NULL
assignment, a reader that also takes conn_lock either runs fully before
the allocation or fully after the NULL store, and can never observe the
freed-but-not-yet-NULLed pointer. ksmbd_gen_preauth_integrity_hash()
takes no locks itself (it only computes a SHA-512 over the buffer), so
no lock-ordering inversion is introduced, and conn_lock is a sleepable
mutex which is safe on this send path (it already performs network I/O). |
| In the Linux kernel, the following vulnerability has been resolved:
can: isotp: use unconditional synchronize_rcu() in isotp_release()
isotp_notify() unregisters the (RCU) CAN filters via can_rx_unregister()
and clears so->bound without waiting for a grace period. isotp_release()
uses so->bound to decide whether it needs to call synchronize_rcu()
before cancelling so->rxtimer, so when NETDEV_UNREGISTER runs first it
skips that synchronize_rcu() and can cancel the timer while an
in-flight isotp_rcv() is still executing and about to re-arm it via
isotp_send_fc(), leading to a use-after-free timer callback on the
freed socket.
sakisho-bot remarked a problem with rtnl_lock held in isotp_notify(),
therefore make isotp_release() always call synchronize_rcu() before
cancelling the timers, regardless of so->bound. This still closes the
original race (isotp_notify() clearing so->bound without waiting for
in-flight isotp_rcv() callers before isotp_release() cancels the RX
timer) without adding any RCU wait to the netdevice notifier path. |
| In the Linux kernel, the following vulnerability has been resolved:
vxlan: use neigh_ha_snapshot() in route_shortcircuit()
The neighbour hardware address n->ha can be updated asynchronously by the
neighbour subsystem, protected by n->ha_lock seqlock. Reading n->ha without
holding the seqlock loop can lead to torn reads or reading a partially updated
MAC address.
Use neigh_ha_snapshot() in route_shortcircuit() to safely copy n->ha under
read_seqbegin()/read_seqretry() lock protection before using it.
Note that arp_reduce() and neigh_reduce() seem to have the same issue
left for future patches. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: nVMX: Move vTPR vs. TPR Threshold consistency check into "normal" checks
Move the off-by-default consistency check for vmcs12.tpr_threshold vs.
the virtual APIC vTPR into the "normal" controls checks, as waiting until
KVM has loaded some amount of state is unnecessary and actively dangerous.
Specifically, failure to unwind vmcs01.GUEST_CR3 to KVM's value when EPT
is disabled results in KVM running L1 with an L1-controlled CR3, not with
KVM's CR3!
Alternatively, KVM could simply reset the MMU to force a reload of
vmcs01.GUEST_CR3, but the _only_ reason the check was shoved into a "late"
flow was to wait until the vmcs12 pages were retrieved. Rather than build
up more crusty code, simply access vTPR using a regular guest memory access
(performance isn't a concern). To circumvent the restrictions that led to
KVM deferring nested_get_vmcs12_pages(), (a) use a VM-scoped API to read
guest memory so that it always hits non-SMM memslots (for RSM), and (b)
skip the check (since its off-by-default anyways) when the vCPU doesn't
want to run, i.e. when userspace is restoring/stuffing state.
If reading guest memory fails, simply skip the consistency check, as KVM's
de facto ABI is that VMX instruction accesses to non-existent memory get
PCI Bus Error semantics, where reads return 0xFFs. And if vTPR=0xFF, then
the vTPR is guaranteed to be greater than or equal to TPR_THRESHOLD. |
| In the Linux kernel, the following vulnerability has been resolved:
dm thin metadata: fix metadata snapshot consistency on commit failure
__reserve_metadata_snap() and __release_metadata_snap() modify the
superblock's held_root directly in the block_manager's buffer. If the
subsequent metadata commit fails, the held_root gets flushed to disk
through the abort_transaction path, resulting in inconsistent metadata.
Reproducer 1: __reserve_metadata_snap()
1. Create a 2 MiB metadata device and make the region after the 14th
block inaccessible, to trigger metadata commit failure in the
subsequent reserve_metadata_snap operation. The 14th block will be
the shadow destination for the index block.
dmsetup create tmeta --table "0 112 linear /dev/sdc 0
112 3984 error"
2. Create a 16 MiB thin-pool
dmsetup create tdata --table "0 32768 zero"
dd if=/dev/zero of=/dev/mapper/tmeta bs=4k count=1
dmsetup create tpool --table "0 32768 thin-pool /dev/mapper/tmeta \
/dev/mapper/tdata 128 0 1 skip_block_zeroing"
3. Take a metadata snapshot to trigger metadata commit failure and
transaction abort. However, the held_root is written to disk,
breaking metadata consistency.
dmsetup message tpool 0 "reserve_metadata_snap"
thin_check v1.2.2 result:
Bad reference count for metadata block 6. Expected 2, but space map contains 1.
Bad reference count for metadata block 7. Expected 2, but space map contains 1.
Bad reference count for metadata block 13. Expected 1, but space map contains 0.
Reproducer 2: __release_metadata_snap()
1. Create a 2 MiB metadata device and make the region after the 16th
block inaccessible, to trigger metadata commit failure in the
subsequent release_metadata_snap operation. The 16th block will be
the shadow destination for the index block.
dmsetup create tmeta --table "0 128 linear /dev/sdc 0
128 3968 error"
2. Create a 16 MiB thin-pool
dmsetup create tdata --table "0 32768 zero"
dd if=/dev/zero of=/dev/mapper/tmeta bs=4k count=1
dmsetup create tpool --table "0 32768 thin-pool /dev/mapper/tmeta \
/dev/mapper/tdata 128 0 1 skip_block_zeroing"
3. Reserve then release the metadata snapshot, to trigger metadata
commit failure and transaction abort. The held_root gets removed
from the on-disk superblock, causing inconsistent metadata.
dmsetup message tpool 0 "reserve_metadata_snap"
dmsetup message tpool 0 "release_metadata_snap"
thin_check v1.2.2 result:
Bad reference count for metadata block 6. Expected 1, but space map contains 2.
Bad reference count for metadata block 7. Expected 1, but space map contains 2.
1 metadata blocks have leaked.
Fix by deferring the held_root update to commit time.
Additionally, move the existing-snapshot check in __reserve_metadata_snap
before the shadow operation to avoid unnecessary work. In
__release_metadata_snap, clear pmd->held_root before btree deletion so
partial failure leaks blocks rather than leaving a stale reference, and
unlock the snapshot block before decrementing its refcount. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Reset register bounds before narrowing retval range in check_mem_access()
When the BPF verifier processes a context load of an LSM hook return
value, it calls __mark_reg_s32_range() to narrow the register to the
hook's valid range. However, __mark_reg_s32_range() intersects the new
range with the register's existing bounds using max_t()/min_t() rather
than replacing them.
If the destination register carries stale bounds from a prior instruction
(e.g. BPF_MOV64_IMM), the intersection can produce a range narrower than
reality. The verifier then believes it knows the register's exact value,
while at runtime the actual hook return value is loaded, creating a
verifier/runtime mismatch that can be used to bypass BPF memory safety
checks.
The else branch already calls mark_reg_unknown() to reset register state
before any narrowing. Apply the same reset in the is_retval path so
stale bounds are cleared before __mark_reg_s32_range() intersects. |
| In the Linux kernel, the following vulnerability has been resolved:
can: bcm: add locking when updating filter and timer values
KCSAN detected a simultaneous access to timer values that can be
overwritten in bcm_rx_setup() when updating timer and filter content
while bcm_rx_handler(), bcm_rx_timeout_handler() or bcm_rx_thr_handler()
run concurrently on incoming CAN traffic.
Protect the timer (ival1/ival2/kt_ival1/kt_ival2/kt_lastmsg) and filter
(nframes/flags/frames/last_frames) updates in bcm_rx_setup() with a new
per-op bcm_rx_update_lock, taken with the matching scope in the RX
handlers. memcpy_from_msg() is staged into a temporary buffer before the
lock is taken, since it can sleep and must not run under a spinlock.
hrtimer_cancel() is always called without bcm_rx_update_lock held, since
bcm_rx_timeout_handler()/bcm_rx_thr_handler() take the same lock and a
running callback would otherwise deadlock against the canceller.
Also close a related race: bcm_rx_setup() cleared the RTR flag in the
stored reply frame's can_id as a separate, unprotected step after the
frame content was already installed, so a concurrent bcm_rx_handler()
could transmit a stale reply with CAN_RTR_FLAG still set. Fold that
normalization into the initial frame preparation instead (on the staged
buffer for updates, directly on op->frames pre-registration for new
ops), so the installed frame is always atomically self-consistent.
bcm_rx_handler()'s RX_RTR_FRAME check now takes a lock-protected
snapshot of op->flags before deciding whether to call bcm_can_tx(),
but does not hold the lock across that call.
Also take a lock-protected snapshot of the currframe in bcm_can_tx()
to avoid partly overwrites by content updates in bcm_tx_setup().
Finally check if a TX_RESET_MULTI_IDX/SETTIMER might have reset
op->currframe between the two locked sections in bcm_can_tx().
Omit calling hrtimer_forward() with zero interval in bcm_rx_thr_handler().
kt_ival2 may have been concurrently cleared by bcm_rx_setup() before it
cancels this timer, so check kt_ival2 inside the bcm_rx_update_lock. |
| In the Linux kernel, the following vulnerability has been resolved:
can: bcm: fix lockless bound/ifindex race and silent RX_SETUP failure
bcm_sendmsg() reads bo->ifindex and checks bo->bound before taking
lock_sock(), while bcm_notify(), bcm_connect() and bcm_release() all
mutate both fields under that same lock. Because the lockless reads
and the locked writes are unordered with respect to each other, a
racing bcm_notify() (device unregister) or bcm_connect() (concurrent
bind on another thread sharing the socket) can make bcm_sendmsg()
observe an inconsistent combination, e.g. a stale bound=1 together
with the now-cleared ifindex=0, silently turning a socket bound to a
specific CAN interface into one that also matches "any" interface.
Keep the lockless bo->bound check purely as a fast-path reject, and
move the ifindex read (and a bo->bound re-check) into the locked
section, where every writer already serializes. This removes the
possibility of observing the two fields torn against each other,
rather than trying to fix it with more READ_ONCE()/WRITE_ONCE() pairs
on two independently updated fields. Annotate the now-purely-lockless
bo->bound accesses consistently across all its write sites.
Also fix bcm_rx_setup() silently returning success when the target
device disappears concurrently instead of reporting -ENODEV, so a
broken RX op is no longer left registered as if it had succeeded. |
| 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. |
| Budibase is an open-source low-code platform. Prior to 3.40.0, packages/backend-core/src/utils/outboundFetch.ts pinned a validated address through a Node agent, but the REST integration used getDispatcher from packages/backend-core/src/utils/fetch.ts, causing undici to ignore that agent and resolve the hostname again. A builder could use DNS rebinding to make packages/server/src/integrations/rest.ts connect to an internal address after a public address passed validation, with full response access and arbitrary REST methods. The fix adds createPinnedLookup support to the undici dispatcher and passes the validated address to custom fetch implementations. This issue is fixed in version 3.40.0. |
| In the Linux kernel, the following vulnerability has been resolved:
ocfs2: avoid moving extents to occupied clusters
For non-auto OCFS2_IOC_MOVE_EXT operations, userspace supplies a physical
me_goal. ocfs2_move_extent() initializes new_phys_cpos from that goal and
expects ocfs2_probe_alloc_group() to replace it with a free run in the
target block group.
The probe currently leaves *phys_cpos unchanged if the scan reaches the
end of the group without finding a free run. An occupied goal at the last
bit can therefore survive the probe and be passed to
__ocfs2_move_extent(), which copies file data into a cluster still owned
by another inode before the bitmap is updated.
When the probe does find a free run, it also subtracts move_len from the
ending bit. The start of an N-bit run ending at i is i - N + 1, so the
current calculation can report the bit immediately before the free run.
Clear *phys_cpos before scanning and use the correct free-run start.
Callers already treat a zero result as -ENOSPC, so failed probes no longer
continue with an occupied caller-controlled goal. |
| In the Linux kernel, the following vulnerability has been resolved:
fs/proc/task_mmu: fix make_uffd_wp_huge_pte() prot-update race
Patch series "userfaultfd/pagemap: pre-existing fixes".
These are pre-existing bug fixes that were carried at the front of the
userfaultfd RWP working-set-tracking series up to v5 [1]. Per review
feedback that fixes should not sit in the middle of a feature series, they
are split out and sent on their own; the RWP series is reposted rebased on
top of this.
All six were flagged by the Sashiko AI review of the RWP series and carry
independent of RWP, apply to mm-new directly, and carry Cc: stable@.
1: fs/proc/task_mmu: a missing huge_ptep_modify_prot_start() in
make_uffd_wp_huge_pte() can lose hardware Dirty/Accessed updates
when PAGEMAP_SCAN write-protects a hugetlb PTE.
2: fs/proc/task_mmu: pagemap_scan_hugetlb_entry() compares the range
against HPAGE_SIZE rather than the hstate page size, so it never
write-protects gigantic hugetlb pages.
3: fs/proc/task_mmu: PAGEMAP_SCAN with PM_SCAN_WP_MATCHING over an
unpopulated hugetlb range self-deadlocks -- pagemap_scan_pte_hole()
calls uffd_wp_range() while walk_hugetlb_range() holds the hugetlb
vma lock for read, and hugetlb_change_protection() then takes it
for write. Install the marker inline instead.
4: mm/huge_memory: change_non_present_huge_pmd() drops pmd_swp_uffd_wp
on a device-private PMD permission downgrade, silently losing the
uffd-wp marker.
5: userfaultfd: must_wait() applies pte_write() to a locklessly read
PTE without checking pte_present(), so swap/migration entries
decode random offset bits and a thread can stay parked on a stale
fault.
6: userfaultfd: __VMA_UFFD_FLAGS feeds VMA_UFFD_MINOR_BIT (41) to
mk_vma_flags() unconditionally, an out-of-bounds write into the
single-word vma_flags_t on 32-bit. Build the mask from config-gated
per-mode masks so an unavailable bit is never materialised.
This patch (of 6):
make_uffd_wp_huge_pte() arms the UFFD_WP bit on a present HugeTLB PTE by
calling huge_ptep_modify_prot_commit() with a ptent snapshot that was
fetched without the corresponding huge_ptep_modify_prot_start(). The
start helper is what atomically clears the entry so the kernel-owned
snapshot stays consistent until the commit; without it, the hardware may
set Dirty or Accessed in the live PTE between the original read and the
commit, and huge_ptep_modify_prot_commit() (whose generic implementation
just calls set_huge_pte_at()) then writes the stale snapshot back over the
live hardware bits, losing the update.
The non-hugetlb sibling make_uffd_wp_pte() does this correctly via
ptep_modify_prot_start() / ptep_modify_prot_commit(). Mirror that pattern
for the present-PTE branch. The migration case stays as-is -- migration
entries are non-present, so there's no hardware update to race against. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: Move kvm_io_bus_get_dev() locking responsibilities to callers
kvm_io_bus_get_dev() returns a device that is only matched by the
address, and nothing else. This can cause a lifetime issue if
the matched device is not the expected type, as by the time
the caller can introspect the object, it might be gone (the srcu
lock having been dropped).
Given that there is only a single user of this helper, the simplest
option is to move the locking responsibility to the caller, which
can keep the srcu lock held for as long as it wants.
Note that this aligns with other kvm_io_bus*() helpers, which
already require the srcu lock to be held by the callers. |
| In the Linux kernel, the following vulnerability has been resolved:
ksmbd: close durable scavenger races against m_fp_list lookups
ksmbd_durable_scavenger() has two related races against any walker
that iterates f_ci->m_fp_list, including ksmbd_lookup_fd_inode()
(used by ksmbd_vfs_rename) and the share-mode checks in
fs/smb/server/smb_common.c.
(1) fp->node list-head reuse. Durable-preserved handles can remain
linked on f_ci->m_fp_list after session teardown so share-mode checks
still see them while the handle is reconnectable. The scavenger
collected expired handles by adding fp->node to a local
scavenger_list after removing them from the global durable idr.
Because fp->node is the same list_head used by m_fp_list,
list_add(&fp->node, &scavenger_list) overwrites the m_fp_list links
and corrupts both lists. CONFIG_DEBUG_LIST can report this on the
share-mode walk path.
(2) Refcount race against m_fp_list walkers. The scavenger qualifies
an expired durable handle with atomic_read(&fp->refcount) > 1 and
fp->conn under global_ft.lock, removes fp from global_ft, then drops
global_ft.lock before unlinking fp from m_fp_list and freeing it.
During that gap fp is still linked on m_fp_list with f_state ==
FP_INITED. ksmbd_lookup_fd_inode() under m_lock read calls
ksmbd_fp_get() (atomic_inc_not_zero on refcount that is still 1) and
takes a live reference; the scavenger then unlinks and frees fp
while the holder owns a reference, leading to UAF on the holder's
subsequent ksmbd_fd_put() and on any field reads performed by a
concurrent share-mode walker that iterates m_fp_list without taking
ksmbd_fp_get() (smb_check_perm_dleases-like paths).
Fix both:
* Stop reusing fp->node as a scavenger-private list node. Remove
one expired handle from global_ft under global_ft.lock, take an
explicit transient reference, drop the lock, unlink fp->node
from m_fp_list under f_ci->m_lock, then drop both the durable
lifetime and transient references with atomic_sub_and_test(2,
&fp->refcount). If the scavenger is the last putter the close
runs there; otherwise an in-flight holder that already raced
through the m_fp_list lookup owns the final close via its
ksmbd_fd_put() path. The one-at-a-time disposal can rescan the
durable idr when multiple handles expire in the same pass, but
durable scavenging is a background expiration path and the final
full scan recomputes min_timeout before the next wait.
* Clear fp->persistent_id inside __ksmbd_remove_durable_fd() right
after idr_remove(), so a delayed final close from a holder that
snatched fp does not re-issue idr_remove() on a persistent id
that idr_alloc_cyclic() in ksmbd_open_durable_fd() may have
already handed out to a brand-new durable handle.
* Bypass the per-conn open_files_count decrement in
__put_fd_final() when fp is detached from any session table
(fp->conn cleared by session_fd_check() at durable preserve --
paired with the volatile_id clear at unpublish, so checking
fp->conn alone is sufficient). The walker that owns the final
close runs from an unrelated work->conn whose
stats.open_files_count never tracked this durable fp; without
this guard the holder would underflow that unrelated counter.
The two races are folded into one patch because patch (1) alone
cleans up the corrupted list but leaves a deterministic UAF window
for m_fp_list walkers that the transient-reference and
persistent_id discipline in (2) close; bisecting onto an
intermediate state would land on a UAF that pre-patch chaos merely
made less reproducible.
Validation:
* CONFIG_DEBUG_LIST coverage for the list_head reuse path.
* KASAN-enabled direct SMB2 durable-handle coverage that exercised
ksmbd_durable_scavenger() and non-NULL ksmbd_lookup_fd_inode()
returns while durable handles expired under concurrent rename
lookups, with no KASAN, UAF, list-corruption, ODEBUG, or WARNING
reports.
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
9p: skip nlink update in cacheless mode to fix WARN_ON
v9fs_dec_count() unconditionally calls drop_nlink() on regular files,
even when the inode's nlink is already zero. In cacheless mode the
client refetches inode metadata from the server (the source of truth)
on every operation, so by the time v9fs_remove() returns, the locally
cached nlink may already reflect the post-unlink value:
1. Client initiates unlink, server processes it and sets nlink to 0
2. Client refetches inode metadata (nlink=0) before unlink returns
3. Client's v9fs_remove() completes successfully
4. Client calls v9fs_dec_count() which calls drop_nlink() on nlink=0
This race is easily triggered under heavy unlink workloads, such as
stress-ng's unlink stressor, producing the following warning:
WARNING: fs/inode.c:417 at drop_nlink+0x4c/0xc8
Call trace:
drop_nlink+0x4c/0xc8
v9fs_remove+0x1e0/0x250 [9p]
v9fs_vfs_unlink+0x20/0x38 [9p]
vfs_unlink+0x13c/0x258
...
In cacheless mode the server is authoritative and the inode is on its
way out, so locally adjusting nlink buys nothing. Skip v9fs_dec_count()
entirely when neither CACHE_META nor CACHE_LOOSE is set, which both
avoids the warning and removes a class of nlink races (two concurrent
unlinkers observing nlink > 0 and both calling drop_nlink()) that an
nlink == 0 guard alone would only narrow rather than close. |
