| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: caiaq: Decoupling ep1_in_urb in caiaq dev
The epq_in_urb object belonging to the caiaq device is coupled within
the struct snd_usb_caiaqdev. After usb_submit_urb(epq_in_urb, GFP_KERNEL)
executes successfully, epq_in_urb is successfully added to the urbp_list
queue of the dummy HCD driver (userspace specifies dummy_hcd as the HCD
layer driver for the caiaq USB device).
When init_card() calls snd_usb_caiaq_send_command() which subsequently
fails due to a timeout, and proceeds to call snd_card_free() to release
the card, the embedded ep1_in_urb object is also freed. When the dummy
HCD driver detects that the URB has been unlinked, it returns the URB
(by usb_hcd_giveback_urb()), which triggers [1].
Decouple the ep1_in_urb object from the struct snd_usb_caiaqdev and switch
to using a pointer instead. Separately allocate and manage the memory for
ep1_in_urb to prevent the release of the snd_card memory object from
interfering with it.
midi_out_urb has the same issue as ep1_in_urb and is handled in the same
way.
[1]
BUG: KASAN: slab-use-after-free in usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
Write of size 4 at addr ffff88803cee1050 by task ktimers/1/29
Call Trace:
usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
dummy_timer+0xaac/0x4d50 drivers/usb/gadget/udc/dummy_hcd.c:2019
__run_hrtimer kernel/time/hrtimer.c:2067 [inline]
__hrtimer_run_queues+0x3eb/0xaf0 kernel/time/hrtimer.c:2124
hrtimer_run_softirq+0x1e1/0x2e0 kernel/time/hrtimer.c:2141
Allocated by task 36:
snd_card_new+0x7b/0x110 sound/core/init.c:184
create_card sound/usb/caiaq/device.c:429 [inline]
snd_probe+0x236/0x1af0 sound/usb/caiaq/device.c:544
Freed by task 36:
snd_card_free_when_closed sound/core/init.c:630 [inline]
snd_card_free+0x138/0x1d0 sound/core/init.c:662
snd_probe+0x162b/0x1af0 sound/usb/caiaq/device.c:553 |
| In the Linux kernel, the following vulnerability has been resolved:
net/mlx5: E-Switch, prevent mc_list repopulation during vport disable
In mlx5_esw_vport_disable(), move esw_apply_vport_rx_mode() ahead
of esw_vport_change_handle_locked() so vport->allmulti_rule is
NULL before the change handler observes it.
During FW-fatal recovery the disable runs while dev->state ==
INTERNAL_ERROR. The promisc query inside esw_update_vport_rx_mode()
fails and returns early, leaving vport->allmulti_rule intact, so
esw_update_vport_mc_promisc() runs and adds MLX5_ACTION_ADD entries
to vport->mc_list whose flow rules are then installed in the FDB
by esw_add_mc_addr(). esw_destroy_legacy_table() tears down the
FDB with those refs still held, corrupting the sub-tree and
leaving dangling flow_rule pointers in vport->mc_list.
Two-stage failure on `echo 1 > /sys/bus/pci/devices/<bdf>/reset`:
refcount_t: underflow; use-after-free.
tree_put_node+0xef/0x110 [mlx5_core]
clean_tree+0x44/0xd0 [mlx5_core] (x5)
mlx5_fs_core_cleanup+0x57/0x1c0 [mlx5_core]
mlx5_unload+0x65/0xd0 [mlx5_core]
... mlx5_health_try_recover
BUG: unable to handle page fault for address: 0000000003000055
down_write+0x1c/0x60
mlx5_del_flow_rules+0x33/0x1f0 [mlx5_core]
esw_del_mc_addr+0x7b/0x170 [mlx5_core]
esw_apply_vport_addr_list+0x56/0xf0 [mlx5_core]
esw_vport_change_handle_locked+0x28b/0x310 [mlx5_core]
mlx5_esw_vport_enable+0x270/0x4a0 [mlx5_core]
... mlx5_load ... mlx5_health_try_recover
esw_apply_vport_rx_mode(false, false) clears vport->allmulti_rule
via its local state machine even when the FW del fails. With the
rule NULL the !IS_ERR_OR_NULL(allmulti_rule) gate in the change
handler closes, no rules are installed during disable, and the
reload starts with a clean mc_list. |
| In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: Fix use-after-free race in sample_restore_put()
Concurrent teardown of TC sample rules sharing the same restore
context may re-read restore->count after dropping restore_lock.
At that point another thread may already have completed cleanup and
freed the restore object.
Use the result of the refcount decrement while holding restore_lock to
determine whether cleanup is needed. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Skip vport under deletion in report ID acquisition
qla24xx_report_id_acquisition() format-1 handling walks ha->vp_list under
vport_slock, takes a vref_count on the matching vport and calls
qla_update_host_map() to register its port id.
A vport teardown via qla24xx_vport_delete() sets VPORT_DELETE, then
qla24xx_disable_vp() removes the vport from the host_map btree and zeroes
vha->d_id (RESET_AL_PA). The vport is only unlinked from vp_list later,
in qla24xx_deallocate_vp_id(), which clears vp_map[idx] (RESET_VP_IDX)
but does not touch host_map. In the window in between, report ID
acquisition can still find the vport on vp_list and call
qla_update_host_map(); with d_id already zeroed it takes the
btree_insert32() path and re-inserts the dying vport into host_map.
Nothing cleans that entry afterwards, so once scsi_host_put() frees the
vha a later host_map lookup dereferences freed memory.
Skip a vport that has VPORT_DELETE set before taking the reference, so it
is neither re-registered nor scheduled for DPC re-registration. This
mirrors the existing guard in qla2x00_alert_all_vps(). |
| In the Linux kernel, the following vulnerability has been resolved:
mac802154: fix use-after-free of sdata via queued RX frames
The RX softirq producer ieee802154_subif_frame() queues received beacon
and MAC-command frames onto local->rx_beacon_list / rx_mac_cmd_list and
schedules a process-context worker, storing a raw mac_pkt->sdata (and
skb->dev == sdata->dev) with neither a reference nor any locking:
- the lists have no lock: the softirq producer list_add_tail()s while the
mac_wq worker list_del()s, so sibling interfaces on the same phy corrupt
the list;
- the workers dereference the interface after it may have been freed.
mac802154_rx_mac_cmd_worker() touches mac_pkt->sdata directly, and
mac802154_rx_beacon_worker() -> mac802154_process_beacon() dereferences
skb->dev (== sdata->dev). Removing an interface frees its sdata
(netdev_priv) while a queued frame still points at it, so a later worker
run is a use-after-free.
Reproduced under KASAN by flooding a victim interface with MAC command
frames and removing it (the beacon path is the same class via skb->dev):
BUG: KASAN: slab-use-after-free in mac802154_rx_mac_cmd_worker+0x463/0x630 [mac802154]
Read of size 4 at addr ffff888002f9ea18 by task kworker/u8:1/31
Workqueue: phy0-mac-cmds mac802154_rx_mac_cmd_worker [mac802154]
Call Trace:
mac802154_rx_mac_cmd_worker+0x463/0x630 [mac802154]
process_one_work+0x611/0xe80
worker_thread+0x52e/0xdc0
kthread+0x30c/0x630
ret_from_fork+0x2fd/0x3e0
Fix both lists together:
- add local->rx_lock and take it around every list access: the softirq
producer (plain spin_lock, softirq context) and the workers and flush
(spin_lock_bh, process context);
- pin the interface for the lifetime of a queued frame with
netdev_hold()/netdev_put(), so the worker can safely dereference sdata /
skb->dev even while the interface is being removed;
- dequeue under the lock at the head and loop-drain the whole list in the
workers (they previously processed one frame per run and relied on a
later enqueue to drain the rest);
- drop not-yet-started frames of an interface before it is unregistered,
from ieee802154_if_remove() (after the RCU grace period) and from the
ieee802154_remove_interfaces() loop -- the latter is the whole-phy
teardown path, which does not go through ieee802154_if_remove().
An in-flight worker that already dequeued a frame keeps its own netdev
reference; unregister_netdevice() then waits it out in netdev_run_todo(),
which runs at rtnl_unlock() (rtnl released) and after the interface has
been closed, so it does not pin rtnl. A worker blocked in an association
TX only delays that one interface's unregister (the usual "waiting for %s
to become free"), it does not hold rtnl. netdev_hold() is used for this
reason instead of a cancel_work_sync() under rtnl, which would block on
the worker's unbounded MLME TX wait via ieee802154_sync_queue().
The mac-command worker additionally skips processing for a stopped
interface (ieee802154_sdata_running()), avoiding a needless association
response during teardown. |
| In the Linux kernel, the following vulnerability has been resolved:
x86/mm/pat: Allocate split page tables as kernel page tables
A PTE is allocated directly without going through the standard page table
allocation routines (such as pte_alloc_one_kernel()) when the CPA code
splits a large page (__split_large_page()).
This means the page table constructor is never called nor is the page table
marked as a kernel page table.
The former results in the folio associated with the page table not being
marked as a page table (__pagetable_ctor() is never called thus neither is
__folio_set_pgtable()) nor are statistics updated to reflect
it (lruvec_stat_add_folio() is never called).
The latter issue of failing to mark the page table as a kernel page
table (ptdesc_set_kernel() is never called) is far more problematic.
Since commit:
5ba2f0a15564 ("mm: introduce deferred freeing for kernel page tables")
kernel page table freeing has been batched and since the
subsequent commit:
e37d5a2d60a3 ("iommu/sva: invalidate stale IOTLB entries for kernel address space")
IOTLB cache entries for kernel page tables have been invalidated upon
being freed.
Since split page tables are freed without this invalidation, the IOTLB
can contain stale entries for them.
Resolve the issue by using the ordinary PTE allocation API at split time.
This results in these kernel page tables invoking a page table constructor,
and thus requires a page table destructor.
Destructors are not always present, like for early allocated direct map
page tables). Conditionally call pagetable_dtor_free() if the PG_table
folio flag for the ptdesc is set, otherwise we free the page table via
pagetable_free().
Regardless of which path is taken page tables marked as kernel page tables,
which now includes split page tables, take the correct route through
pagetable_free_kernel().
There is a user-visible side effect in that split page tables will appear
in nr_page_table_pages in /proc/vmstat (as do other kernel page tables
allocated after early boot), however this is a positive change.
This issue started being markedly problematic after commit:
5ba2f0a15564 ("mm: introduce deferred freeing for kernel page tables")
so choose this as the Fixes target.
[ dhansen: rephrase in imperative mood ] |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Unlink NVMe unsol ctx before freeing on LS reject error
qla_nvme_xmt_ls_rsp() obtains uctx, which was linked into
fcport->unsol_ctx_head by qla2xxx_process_purls_iocb() and is still linked
when the NVMe transport calls back to transmit the LS response. On the
error (out:) path the function frees uctx with kfree() but never removes
it from the list. This leaves a freed node in fcport->unsol_ctx_head: the
next list_add_tail() for that fcport writes through the freed node, and a
subsequent list_del() can corrupt the list or panic.
Unlink uctx with list_del() before kfree() on the error path, matching the
other free sites in qla_nvme_release_lsrsp_cmd_kref() and
qla2xxx_process_purls_pkt(). qla2x00_rel_sp() in the failure path only
returns the SRB to its pool and does not invoke sp->put_fn, so the out:
path is the sole free and uctx is always still linked there. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Fix use-after-free of qpair work on queue teardown
The response queue MSI-X handler qla2xxx_msix_rsp_q() schedules
qla_do_work() via queue_work(ha->wq, &qpair->q_work). qla_do_work()
dereferences the qpair (vha, rsp) and takes qpair->qp_lock.
During teardown, qla2xxx_delete_qpair() deletes the response queue, which
calls free_irq() in qla25xx_free_rsp_que(), and then frees the queue and
the qpair. free_irq() waits for running hardirq handlers but does not
cancel work already placed on ha->wq. A still-pending q_work then runs
qla_do_work() against the freed qpair and response queue, causing a
use-after-free. This is especially likely during full adapter teardown,
where destroy_workqueue(ha->wq) forces pending work to run after the queue
pairs have been freed.
Flush the work item with cancel_work_sync() in qla25xx_free_rsp_que()
after free_irq() has released the interrupt (so no new work can be
queued) and before the response queue and qpair memory are freed (so the
flushed handler still sees valid memory). Guard on rsp->qpair and ha->wq
to match the INIT_WORK() condition and avoid operating on an
uninitialized work_struct. |
| In the Linux kernel, the following vulnerability has been resolved:
vxlan: mdb: Fix use-after-free in vxlan_mdb_remote_src_del()
vxlan_mdb_is_valid_source(), which validates MDBE_ATTR_SOURCE and every
MDBE_ATTR_SRC_LIST member, accepts the all-zeros address.
A source list is only accepted on a (*, G) entry, whose source is the
all-zeros address, and for each member of the list an (S, G) entry is
derived from it by substituting the source. Entries are keyed by a plain
memcmp() of struct vxlan_mdb_entry_key, so if MDBE_ATTR_SOURCE is present
and holds the all-zeros address and the source list holds it as well, the
derived (S, G) key is byte-identical to the (*, G) key and resolves to the
same entry. Omitting MDBE_ATTR_SOURCE is not equivalent, as the key is
then left with a zero address family.
vxlan_mdb_remote_src_del() removes the forwarding entry of a source before
freeing the source entry:
vxlan_mdb_remote_src_fwd_del(vxlan, group, remote, &ent->addr);
vxlan_mdb_remote_src_entry_del(ent);
With the keys aliased, the first call deletes the remote of the entry that
owns 'ent' instead of a separate (S, G) entry, and frees 'ent'. The second
call then runs on the freed entry, and its hlist_del() reads ->pprev and
->next out of it and writes through them.
Adding the (*, G) entry with NLM_F_REPLACE and no source list marks the
all-zeros source for deletion and reaches this from the sweep at the end
of vxlan_mdb_remote_srcs_replace().
BUG: KASAN: slab-use-after-free in __vxlan_mdb_add+0x1cd/0xd70
Read of size 8 at addr ffff888102852500 by task poc/84
__vxlan_mdb_add+0x1cd/0xd70
vxlan_mdb_add+0xc0/0x140
rtnl_mdb_add+0x157/0x2a0
rtnetlink_rcv_msg+0x207/0x5a0
Allocated by task 84:
__kmalloc_cache_noprof+0x153/0x360
vxlan_mdb_remote_srcs_add+0x2eb/0x440
__vxlan_mdb_add+0x803/0xd70
Freed by task 84:
kfree+0x14c/0x3b0
vxlan_mdb_remote_del+0x129/0x1a0
__vxlan_mdb_del+0x4f/0xe0
vxlan_mdb_remote_src_fwd_del.isra.0+0x162/0x1b0
__vxlan_mdb_add+0x1c5/0xd70
The MDB operations are netns-scoped, so an unprivileged user can perform
them in a new user and network namespace.
Reject the all-zeros address in vxlan_mdb_is_valid_source(), which covers
both call sites. A (*, G) entry is expressed by omitting the source, so
nothing legitimate is refused.
Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com> |
| In the Linux kernel, the following vulnerability has been resolved:
sctp: fix a TOCTOU race in SCTP_CMD_TIMER_START
The SCTP_CMD_TIMER_START handler checks timer_pending() before calling
timer_reduce(). The timer can expire and detach between these operations,
causing timer_reduce() to rearm the timer without taking the association
reference required for the newly armed timer.
The timer callback later unconditionally drops its association reference,
which can leave the association reference count unbalanced and result in
use-after-free during association teardown.
Use the return value of timer_reduce() to determine whether the timer was
actually armed. Take the association reference only when timer_reduce()
successfully starts a new timer, closing the race between checking the
timer state and rearming it.
This issue was reported by Nico Yip (@_cyeaa_) working with TrendAI Zero
Day Initiative. |
| In the Linux kernel, the following vulnerability has been resolved:
hwmon: (gpio-fan) Fix use-after-free in alarm work
fan_alarm_irq_handler() queues fan_data->alarm_work, but nothing
cancels it. fan_alarm_notify() dereferences fan_data and its hwmon
device. On unbind, devres frees the interrupt, which only waits for
the handler itself, and then releases the hwmon device and fan_data,
so a pending fan_alarm_notify() can run after those frees.
Replace INIT_WORK() with devm_work_autocancel(), registered before
devm_request_irq(). The devres cleanup then frees the interrupt
first, so no new work can be queued, and cancels the work while
fan_data and the hwmon device are still alive.
This issue was found by an in-house static analysis tool. |
| In the Linux kernel, the following vulnerability has been resolved:
afs: Clear stale peer app data after address list changes
afs_fs_probe_fileserver() fetches the current endpoint state under
server->fs_lock, but leaves old_alist as NULL. Consequently,
afs_set_peer_appdata() treats every address list replacement as initial
setup and only binds the new peers; it never unbinds peers removed from
the old list.
An address refresh can therefore proceed as follows. CPU 0 replaces
server S's list and drops Pold without clearing Pold->app_data. The
server destroyer then clears only S's current peers and lets S reach its
RCU callback. After the callback frees S, CPU 1 handles a callback
through an RxRPC connection that still pins Pold, reads Pold->app_data,
and calls afs_use_server() on the freed object.
KASAN reported:
BUG: KASAN: slab-use-after-free in afs_find_server+0x3c/0xa0
Read of size 4 at addr ffff8881013e1af0 by task krxrpcio/7001/74
Call Trace:
afs_find_server+0x3c/0xa0
afs_rx_new_call+0x15c/0x390
rxrpc_new_incoming_call+0x97c/0x1730
rxrpc_input_packet.constprop.0+0xd03/0xec0
rxrpc_io_thread+0x967/0x1640
Allocated by task 93:
afs_lookup_server+0x1a7/0x14c0
afs_alloc_server_list+0x43f/0xb60
afs_create_volume+0x923/0x1490
afs_get_tree+0x1c6/0x10a0
Freed by task 0:
kfree+0x131/0x3c0
rcu_core+0x50a/0x1850
Last potentially related work creation:
__call_rcu_common.constprop.0+0x71/0xa10
afs_put_server+0x213/0x2b0
Preserve old->addresses for the peer app-data update so that removed
peers are cleared before the endpoint state is replaced. Also advance
both cursors when the old and new lists share a peer; activating the
old/new comparison without this would otherwise loop forever on the
shared entry. |
| In the Linux kernel, the following vulnerability has been resolved:
landlock: Fix use-after-free of the source's parent directory
current_check_refer_path() reads old_dentry->d_parent without holding a
reference nor a lock on it, and then dereferences it in
collect_domain_accesses() and in the audit record.
A reference on a child does not pin its parent: __d_move() reassigns
dentry->d_parent and drops the reference the child held on its former
parent. hook_path_rename() is not affected because the rename path
calls lock_rename() before the hook, so the source cannot be reparented
under it. hook_path_link() has no such protection: filename_linkat()
holds a reference on the source dentry but neither locks nor references
its parent, so a concurrent rename(2) can reparent the source while
security_path_link() runs, and the former parent can then be removed and
freed while the hook walks it.
A process can trigger this after entering a Landlock domain that handles
at least one filesystem access right. The process can then race a
linkat(2) loop against rename(2) and rmdir(2):
BUG: KASAN: slab-use-after-free in collect_domain_accesses+0x278/0x290
Read of size 4 at addr ffff888160bd53f4 by task llrepro2/549
collect_domain_accesses+0x278/0x290
current_check_refer_path+0x952/0x1120
security_path_link+0x1be/0x320
filename_linkat+0x342/0x6d0
__x64_sys_linkat+0xfa/0x150
Freed by task 562:
kmem_cache_free+0x139/0x4c0
i_callback+0x4b/0x80
rcu_core+0x7dc/0x10a0
Take a reference on the dentry selected as the source parent, using
dget() for the common-mount-root case and dget_parent() otherwise.
Release it after the hierarchy walk and synchronous audit logging.
[mic: Clarify the caller, reachability, and reference handling] |
| In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix listener task lifetime on netdev events
The listener thread exits when its listening socket is shutdown. The
netdevice notifier shuts down the socket before calling kthread_stop(), so
the task_struct can be freed before kthread_stop() gets its reference.
Create the listener in a stopped state and hold an extra task_struct
reference until kthread_stop_put() completes. Also stop and release
listeners before freeing their interface records during TCP teardown. |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: pcm: Serialize PCM mmap with buffer reallocation to fix page UAF
snd_pcm_hw_params() and snd_pcm_hw_free() guard buffer reallocation
with an mmap_count check performed under the PCM stream lock, but the
lock is released long before the buffer is actually freed:
snd_pcm_sync_stop(), constraint refinement and do_free_pages() all
happen in between. snd_pcm_mmap_data(), on the other hand, takes no
lock at all: it validates against the old buffer's state and
dma_bytes, remaps its pages into the VMA, and only then increments
mmap_count.
A concurrent mmap() can therefore slip in between the check and the
free. remap_pfn_range() installs writable PTEs for the old buffer's
pages without taking page references, and the subsequent
do_free_pages() returns those pages to the page allocator while the
VMA still maps them. This leaves a stale, writable mapping of freed
pages: a page-level use-after-free that can be leveraged for local
privilege escalation.
Make snd_pcm_mmap_data() participate in the buffer-access scheme
introduced for hw_params/hw_free: acquire runtime->buffer_accessing
before validating and remapping, and release it afterwards. Buffer
reallocation already fails with -EBUSY while accessors are active,
and the mmap side now fails with -EBUSY while a reallocation is in
progress, so the validate/remap sequence and the check/free sequence
can no longer interleave.
A reproducer that turns this race into a stale writable mapping of
the freed DMA buffer pages is available on request. |
| In the Linux kernel, the following vulnerability has been resolved:
xfrm: Fix dev use-after-free in xfrm async resumption
xfrm async resumption hold skb->dev refcnt until after transport_finish.
However, xfrm_rcv_cb may modify skb->dev to tunnel dev without taking
device reference, such as vti_rcv_cb. The subsequent async resumption
will decrement the tunnel device's reference count, which lead to uaf
of tunnel dev and refcnt leak of orig dev as below:
unregister_netdevice: waiting for vti1 to become free. Usage count = -2
Stash the original skb->dev to fix refcnt imbalance. The new skb->dev set
by xfrm_rcv_cb can race with device teardown. Extend rcu protection over
xfrm_rcv_cb and transport_finish to prevent races. |
| In the Linux kernel, the following vulnerability has been resolved:
pds_core: quiesce DMA before freeing resources
pdsc_teardown() frees DMA buffers but does not disable bus mastering,
leaving the device able to perform DMA after the buffers are freed.
This can lead to use-after-free if the device writes to freed memory.
Add pci_clear_master() to pdsc_teardown() to disable bus mastering
before freeing resources, ensuring all DMA is quiesced.
Add pci_set_master() to pdsc_setup() to re-enable bus mastering,
which is needed for the firmware recovery path since pdsc_teardown()
now disables it. |
| In the Linux kernel, the following vulnerability has been resolved:
HID: hidpp: fix potential UAF in hidpp_connect_event()
If input_register_device() fails, we call input_free_device(), but keep
stale pointer to the old device in hidpp->input, which could potentially
lead to UAF. Fix that by resetting it to NULL before returning from
hidpp_connect_event(). |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: flush pending RCU callbacks on module unload
Call rcu_barrier() in module exit to wait for outstanding call_rcu() callbacks
before freeing module text, preventing late callback execution in freed memory.
BUG: unable to handle page fault for address: ffffffffc1d59c40
PGD 6a12067 P4D 6a12067 PUD 6a14067 PMD 13698b067 PTE 0
Oops: 0010 [#1] SMP NOPTI
RIP: 0010:0xffffffffc1d59c40
Code: Unable to access opcode bytes at RIP 0xffffffffc1d59c16.
RSP: 0018:ffffc900198c0f28 EFLAGS: 00010286
RAX: ffffffffc1d59c40 RBX: ffff897c7d6b61c0 RCX: ffff88826aff4590
RDX: ffff8884d8b35490 RSI: ffffc900198c0f30 RDI: ffff88812af67290
RBP: 000000000000000a (DONE segment entries) R08: 0000000000000000 R09: 0000000000000100
R10: 0000000000000000 R11: ffffffff82a06100 R12: ffff88811a4e3700
R13: 0000000000000000 R14: ffff897c7d6b6270 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff897c7d680000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffc1d59c16 CR3: 00000104a980a001 CR4: 0000000002770ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<IRQ>
? rcu_do_batch+0x163/0x450
? rcu_core+0x177/0x1c0
? __do_softirq+0xc1/0x280
? asm_call_irq_on_stack+0xf/0x20
</IRQ>
? do_softirq_own_stack+0x37/0x50
? irq_exit_rcu+0xc4/0x100
? sysvec_apic_timer_interrupt+0x36/0x80
? asm_sysvec_apic_timer_interrupt+0x12/0x20
? cpuidle_enter_state+0xd4/0x360
? cpuidle_enter+0x29/0x40
? cpuidle_idle_call+0x108/0x1a0
? do_idle+0x77/0xf0
? cpu_startup_entry+0x19/0x20
? secondary_startup_64_no_verify+0xbf/0xcb
(cherry picked from commit feaa5039f6c12acc9aa934c2d45dcd251a12c69f) |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix use-after-free on reloc root after error in insert_dirty_subvol()
If during relocation we fail in insert_dirty_subvol() because
btrfs_update_reloc_root() returned an error, we will leave a root's
reloc_root field pointing to a reloc root that was freed instead of NULL,
resulting later in a use-after-free, or double free attempt during
unmount.
The sequence of steps is this:
1) During relocation the call to btrfs_update_reloc_root() in
insert_dirty_subvol() fails, so insert_dirty_subvol() returns the
error to merge_reloc_root() without adding the root to the list
rc->dirty_subvol_roots;
2) Then merge_reloc_root() aborts the current transaction because
insert_dirty_subvol() returned an error;
3) Up the call chain, merge_reloc_roots() gets the error, adds the
reloc root for root X to the local reloc_roots list and jumps to the
'out' label, where it calls free_reloc_roots() to free all the reloc
roots in the local reloc_roots list. This frees the reloc root for
root X;
4) We go up the call chain to relocate_block_group() which calls
clean_dirty_subvols() to go over dirty roots and set their
->reloc_root field to NULL, but root X is not in the dirty_subvol_roots
list, so its ->reloc_root still points to a reloc root;
5) Relocation finishes, with an error and a transaction abort, but the
->reloc_root field for root X still points to the reloc root that was
freed in step 3;
6) When unmounting the fs we end up calling:
btrfs_free_fs_roots()
btrfs_drop_and_free_fs_root()
--> calls btrfs_put_root() against root X's ->reloc_root
which is not NULL and points to the already freed
reloc root in step 4 above
Resulting in a use-after-free to a double free attempt.
Syzbot reported this with the following dmesg/syslog:
[ 106.004389][ T5339] BTRFS error (device loop0 state A): Transaction aborted (error -5)
[ 106.014266][ T5339] BTRFS: error (device loop0 state A) in merge_reloc_root:1655: errno=-5 IO failure
[ 106.021891][ T1061] BTRFS error (device loop0 state A): error while writing out transaction: -5
[ 106.026964][ T1061] BTRFS warning (device loop0 state A): Skipping commit of aborted transaction.
[ 106.033807][ T5340] BTRFS error (device loop0 state A): bdev /dev/loop0 errs: wr 3, rd 0, flush 0, corrupt 0, gen 0
[ 106.039265][ T1061] BTRFS: error (device loop0 state A) in cleanup_transaction:2067: errno=-5 IO failure
[ 106.044382][ T5339] BTRFS info (device loop0 state EA): forced readonly
[ 106.074329][ T5339] BTRFS: error (device loop0 state EA) in merge_reloc_roots:1887: errno=-5 IO failure
[ 106.081004][ T5356] BTRFS info (device loop0 state EA): scrub: started on devid 1
[ 106.085611][ T5339] BTRFS info (device loop0 state EA): balance: ended with status: -30
[ 106.089517][ T5356] BTRFS info (device loop0 state EA): scrub: not finished on devid 1 with status: -30
[ 106.662365][ T5338] BTRFS info (device loop0 state EA): last unmount of filesystem 3a375e4e-b156-4d76-a2ad-16e198ce1409
[ 106.682946][ T5338] ==================================================================
[ 106.686574][ T5338] BUG: KASAN: slab-use-after-free in btrfs_put_root+0x2f/0x250
[ 106.690090][ T5338] Write of size 4 at addr ffff88803f978630 by task syz.0.0/5338
[ 106.693173][ T5338]
[ 106.694279][ T5338] CPU: 0 UID: 0 PID: 5338 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full)
[ 106.694293][ T5338] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 106.694300][ T5338] Call Trace:
[ 106.694308][ T5338] <TASK>
[ 106.694314][ T5338] dump_stack_lvl+0xe8/0x150
[ 106.694331][ T5338] print_address_description+0x55/0x1e0
[ 106.694343][ T5338] ? btrfs_put_root+0x2f/0x250
[ 106.694358][ T5338] print_report+0x58/0x70
[ 106.
---truncated--- |
