| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
smb: client: reject SetEA requests that do not fit the request buffer
CIFSSMBSetEA() copies the caller's extended attribute value into the
SMB request buffer without checking that it fits. The requirement is
stated in the source but was never implemented:
/*BB add length check to see if it would fit in
negotiated SMB buffer size BB */
/* if (ea_value_len > buffer_size - 512 (enough for header)) */
if (ea_value_len)
memcpy(parm_data->list.name + name_len + 1,
ea_value, ea_value_len);
The only bound applied on the way in is in cifs_xattr_set():
#define MAX_EA_VALUE_SIZE CIFSMaxBufSize
...
if (size > MAX_EA_VALUE_SIZE)
CIFSMaxBufSize is the full payload capacity of the buffer, so a value
of exactly that size leaves no room for the SMB header, the TRANS2
parameter block, the fealist header and the EA name that are written
ahead of it in the same object.
SendReceive() already enforces the correct limit on this very length:
if (in_len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE)
but it is called after the copy has taken place. An unprivileged
setxattr(2) on an SMB1 mount with a 250-byte name and a 16384-byte
value writes 16384 bytes starting 345 bytes into a 16588-byte
cifs_request object, ending 141 bytes past it:
BUG: KASAN: slab-out-of-bounds in CIFSSMBSetEA+0xabc/0xde0
Write of size 16384 at addr ffff888003aa0159 by task init/68
__asan_memcpy+0x3c/0x60
CIFSSMBSetEA+0xabc/0xde0
cifs_xattr_set+0xd3a/0xff0
__vfs_setxattr+0x13e/0x1a0
The buggy address is located 345 bytes inside of
allocated 16588-byte region
Apply SendReceive()'s limit to the assembled request before the copy
rather than after it, and widen the byte counters so the sum cannot
wrap before it is tested.
byte_count is also tested against U16_MAX, because it is stored in the
16-bit pSMB->ByteCount. That becomes reachable when CIFSMaxBufSize is
raised at module load, where it may be set as high as 1024*127: with a
5-byte EA name and a 65521-byte value, count is exactly U16_MAX while
byte_count is 65556, and cpu_to_le16() would truncate it to 20 and
transmit a frame whose ByteCount does not match its length. Testing
byte_count covers count as well, since byte_count is the larger of the
two and count's only 16-bit consumer is written after this point.
check_add_overflow() is evaluated first so that total_len is assigned
before it is reported. |
| In the Linux kernel, the following vulnerability has been resolved:
selinux: fix BPF token permission checks
Avoid multiple lookups of the bpffs creator SID using the token's file
descriptor when the same information can be found via the resolved
path/dentry (in selinux_bpf_token_create()) or the token itself (in
selinux_bpf_map_create() and selinux_bpf_prog_load()). Not only does
this simplify the code, it avoids potential TOCTOU issues if the user
changes the token file descriptor passed into the kernel. |
| In the Linux kernel, the following vulnerability has been resolved:
eventfs: Free the eventfs_inode after an rcu grace period too
tracefs_d_revalidate() reads ->is_freed of the eventfs_inode that
dentry->d_fsdata points to, and ->d_revalidate() is called in rcu
pathwalk mode with nothing but rcu_read_lock() held. The dentry itself
stays around for such a walker, but tracefs_d_release() drops its
reference to the eventfs_inode when the dentry is killed, and
release_ei() then frees it after a grace period of eventfs_srcu. An
SRCU grace period doesn't wait for rcu_read_lock() sections, so the
walker can read an eventfs_inode that is already gone.
With a pathwalk held up in tracefs_d_revalidate() while the dentry goes
away:
BUG: KASAN: slab-use-after-free in tracefs_d_revalidate+0x76/0x90
Read of size 1 at addr ff1100010152d8d0 by task walker/97
Call Trace:
<TASK>
tracefs_d_revalidate+0x76/0x90
lookup_fast+0x320/0x640
path_lookupat+0x160/0xb00
filename_lookup+0x1f1/0x5b0
vfs_statx+0xd7/0x3b0
vfs_fstatat+0x4d/0x90
__do_sys_newfstatat+0xa0/0x100
do_syscall_64+0x10e/0x5e0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
[...]
Allocated by task 1:
__kmalloc_cache_noprof+0x249/0x560
eventfs_create_dir+0x7a/0x590
event_create_dir+0x2fb/0xcf0
trace_add_event_call+0xbf/0x150
[...]
Freed by task 11:
kfree+0x1db/0x5b0
srcu_invoke_callbacks+0x3a3/0x620
process_one_work+0x937/0x1810
worker_thread+0x4f1/0xd60
Before commit 8e556432477e ("eventfs: Use SRCU for freeing
eventfs_inodes") release_ei() used call_rcu(), which covered the walker,
while eventfs_iterate() needs the SRCU grace period. Wait for both and
chain call_rcu() from the SRCU callback. |
| In the Linux kernel, the following vulnerability has been resolved:
fsnotify: prevent mark additions during connector teardown
fsnotify_destroy_marks() keeps a reference to its current mark while it
drops conn->lock to destroy the mark. This stabilizes the forward-walk
cursor, but does not prevent a new mark from being inserted before it.
For example, an inotify watch re-added after IN_IGNORED sorts before the
old, detached mark for the same group. The walk can miss the replacement
and then detach the entire connector from the object.
The replacement is still on its group's marks_list and, for inotify, in
the watch IDR. The group mutex no longer protects the connector's object
from disappearing. An unprivileged fdinfo read racing the final detach
can consequently call igrab(NULL):
BUG: KASAN: null-ptr-deref in igrab+0x24/0x100
Write of size 4 at addr 0000000000000148
Call Trace:
igrab+0x24/0x100
inotify_show_fdinfo+0x1dc/0x5e0
seq_show+0x397/0x690
Set a DESTROYING flag under conn->lock before starting the walk, and
reject new marks on that connector with -ENOENT. The existing add-mark
error paths undo the temporary group-list entry and the backend's watch
allocation. Do not wait for teardown while holding the group mutex,
which the destroyer needs. Once the old connector is detached, an add
can install a fresh connector as before.
This closes the insertion race for all object types using the common
connector teardown, without changing the mark reference or SRCU lifetime
rules. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: SEV: Fix page dirtying in sev_gmem_post_populate()
set_page_dirty() requires that the caller holds some kind of lock to
ensure that the page's mapping does not concurrently go away.
That is not the case for a random page we got from get_user_pages_fast(),
so use set_page_dirty_lock().
[sean: tag for stable] |
| In the Linux kernel, the following vulnerability has been resolved:
autofs: ignore notification errors from a replaced pipe
autofs_notify_daemon() takes a reference to the current notification
pipe under wq_mutex, then drops the mutex before writing the request. The
write can block while the daemon enters catatonic mode and installs a
replacement pipe.
If the old pipe's reader is then closed, the delayed write returns -EPIPE
and the generic error path enters catatonic mode again. That transition
acts on the current superblock state, closes the replacement pipe, and
releases the new daemon generation's wait queues.
Only enter catatonic mode when the pipe which failed is still the current
pipe. Factor the already-locked transition so the identity check and state
change are atomic with respect to another replacement.
This was reproduced on v7.3-rc5-337-gff47652a4b66c in a local QEMU guest.
An unprivileged UID 65534 lookup filled the old packet pipe before a
normal CATATONIC/SETPIPEFD restart. On the unmodified kernel, the new pipe
received HUP and both a pending victim lookup and a later lookup failed
with ENOENT in two out of two fresh-mount runs.
With this change, the new pipe remained active, received an intact
304-byte request, and both victim lookups completed in two out of two
runs. Normal lookup and restart-without-a-blocked-writer controls passed.
No KASAN, oops, refcount, or lock diagnostic was observed. A source
reproducer and complete local logs are available privately on request.
The demonstrated impact is limited to denial of a shared autofs service
during a legitimate daemon restart. No memory corruption, information leak,
privilege escalation, or code execution primitive was observed. |
| In the Linux kernel, the following vulnerability has been resolved:
net: stmmac: dwmac1000: clear the RGMII status interrupt
Since commit 2e2c878a3141 ("net: stmmac: remove SGMII/RGMII/SMII
interrupt handling") nothing on the RGMII path reads GMAC_RGSMIIIS, so
RGSMIIIS stays pending behind GMAC_INT_MASK from the first link change
on. stmmac_resume() resets the MAC in stmmac_hw_setup(); the reset sets
GMAC_INT_MASK to 0 until dwmac1000_core_init() writes the mask again,
and the pending status storms the line:
dwmac_dma_interrupt: unexpected status 04000000
A register dump at the first message on ODROID-HC4 showed it:
core int_status 00000001 int_mask 00000000 pmt 00000000 rgsmiiis 0000000d
When the resume thread runs on the CPU that takes the MAC interrupt,
the storm starves it: a soft lockup, then a watchdog reset or a hang.
Read GMAC_RGSMIIIS in dwmac1000_irq_status() when the status is not
masked, as the driver did before 2e2c878a3141; the read clears it.
Wake-on-LAN resume from s2idle with the resume thread and the MAC
interrupt on one CPU: Helios64 (dwmac-rk), 7.3-rc6, soft-locked in 3 of
3 resumes without a fix and in 0 of 10 with this patch; it ran with an
out-of-tree dwmac-rk change that keeps the GMAC powered across suspend.
ODROID-HC4 (dwmac-meson8b): 0 of 10 with this patch, 2 of 2 without a
fix on a 7.3-rc5 build. irq_rgmii_n went up by one per resume. |
| In the Linux kernel, the following vulnerability has been resolved:
net: ti: icssm-prueth: Move setting of netops to fix crash
icssm_prueth_netdev_init() calls of_phy_get_and_connect() before
ndev->netdev_ops is assigned. phy_attach_direct() ->
phy_link_topo_add_phy() reads dev->netdev_ops through
netdev_need_ops_lock() since the commit in question, so probing crashes
with a NULL pointer dereference when CONFIG_NET_SHAPER is enabled.
Assign netdev_ops before the PHY attach, as was done for emac in commit
7c9f391ec89c ("net: emac: move setting of netops to fix crash"). |
| In the Linux kernel, the following vulnerability has been resolved:
netlink: avoid hashing the network namespace pointer
The netlink rhashtable key includes a raw struct net pointer and a
user-controlled port ID. Both /proc/net/netlink and socket diagnostics
expose the table's bucket order. By binding and rebinding chosen
NETLINK_USERSOCK port IDs, an unprivileged reader can distinguish equal
buckets and recover the low bits of the Jenkins hash. Its 32-bit seed
and the limited set of kernel-image slides can then be searched offline
to recover the address of init_net.
Use the namespace's unique, non-address net_cookie in the comparison
key instead. It is assigned before the per-net initializers run and
remains unchanged for the namespace's lifetime. The lookup key and
object hash are still built by netlink_compare_arg_init(), keeping
lookup, insertion, removal and rehashing consistent while preserving
namespace separation. Neither public table walker needs to change.
Reading the socket's namespace cookie in netlink_compare() is safe
under RCU, including during namespace teardown. netlink_release()
removes the socket from the hash table and defers its final put with
call_rcu(). cleanup_net() runs the per-net exit methods and waits for
outstanding RCU callbacks with rcu_barrier() before freeing namespace
storage.
Unlike ns.ns_id, net_cookie is also available and initialized during
setup_net() in older stable kernels, making the change straightforward
to backport to v5.15 and later. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: target: Disable interrupts while holding delayed_cmd_lock
target_do_delayed_work() takes dev->delayed_cmd_lock with a plain
spin_lock(). It runs from system_percpu_wq, so interrupts stay enabled
while the lock is held. Every other acquisition of that lock uses
spin_lock_irqsave(): target_handle_task_attr() and
transport_complete_ordered_sync() in target_core_transport.c, and
target_non_ordered_release() in target_core_device.c.
That was safe while every caller of transport_complete_task_attr() ran
in process context: target_complete_ok_work() from target_completion_wq,
transport_complete_qf() from dev->qf_work_queue, and
transport_generic_request_failure() from the submit and execute paths.
Since commit 06933066d88a ("scsi: target: Add support for completing
commands from backend context") that is no longer true. With
complete_type=1 on a fabric that sets direct_compl_supp,
target_complete() runs target_complete_ok_work() inline in the backend's
completion context, which target_complete_cmd_with_sense() documents as
"May be called from interrupt context". For iblock that is the bio
end_io.
target_complete_ok_work() starts with transport_complete_task_attr(),
which takes delayed_cmd_lock in two ways:
- Every ORDERED command is put on dev->delayed_cmd_list by
target_handle_task_attr() and dispatched from there by
target_do_delayed_work(), which marks it SCF_TASK_ORDERED_SYNC. Its
completion therefore goes through transport_complete_ordered_sync().
- A SIMPLE command that completes while an ORDERED command is pending
drops the last reference to the killed dev->non_ordered, and
percpu_ref_put() then runs target_non_ordered_release() in the
completing context.
Both take the lock and, if commands are waiting, call
schedule_work(&dev->delayed_cmd_work), which queues on system_percpu_wq,
i.e. on the CPU that took the completion. Further completions for the
same queue are typically delivered there too, so one arriving while the
work holds the lock spins on it forever.
Reaching this needs complete_type=1, which is not the default
(vhost-scsi, the only fabric with direct_compl_supp, defaults to
TARGET_QUEUE_COMPL), a backend whose I/O completes from interrupt
context, and ORDERED commands from the initiator. Linux virtio_scsi
guests send only VIRTIO_SCSI_S_SIMPLE and never take the ordered path;
any guest that uses the ORDERED task attribute, which vhost-scsi
accepts, does.
target_do_delayed_work() is a work item and always runs in process
context, so spin_lock_irq() is sufficient.
Found by inspection; no runtime report. A single ORDERED command goes
through both acquisitions, so with CONFIG_PROVE_LOCKING the first one
completed through direct completion should produce an inconsistent lock
state report on delayed_cmd_lock (hardirq or softirq, depending on where
the backend completes). |
| In the Linux kernel, the following vulnerability has been resolved:
drm/xe: skip eviction of a BO with no resource
xe_evict_flags() switches on tbo->resource->mem_type to choose an
eviction placement. An xe BO can reach eviction with no ttm.resource,
e.g. an imported dma-buf BO whose resource was freed during teardown
while its attachment is still live: the exporter then invalidates it via
xe_dma_buf_move_notify() -> xe_bo_evict(), and the switch dereferences a
NULL resource and faults.
A BO with no resource has nothing placed or mapped, so there is nothing
to evict. Return an empty placement (num_placement = 0), mirroring the
handling already used for non-xe scatter-gather BOs just above;
ttm_bo_validate() then takes the pipeline-gutting path and returns 0.
Without the fix the xe_dma_buf@xe_test_dmabuf_move_notify_no_resource
dynamic live selftest will fail with below stack.
BUG: kernel NULL pointer dereference, address: 0000000000000010
RIP: 0010:xe_evict_flags+0xf4/0x140 [xe]
Call Trace:
<TASK>
xe_bo_evict+0x40/0xa0 [xe]
? ttm_bo_pipeline_gutting+0x71/0x180 [ttm]
xe_test_dmabuf_move_notify_no_resource+0x182/0x440 [xe]
xe_dma_buf_kunit+0x387/0x580 [xe]
v2: Add Fixes tag and failure info in commit text (Matt Brost)
(cherry picked from commit dbcfaac6331f1fcb0c2fe3ad3e9adb1e5d43ec0c) |
| In the Linux kernel, the following vulnerability has been resolved:
accel/rocket: clear rdev on device init failure
rocket_probe() stores the return value from rocket_device_init() in the
file-scoped rdev pointer before checking whether it is an error pointer.
If rocket_device_init() fails, rdev is left as an ERR_PTR.
The rdev pointer is also used as the marker for whether the shared rocket
device has already been initialized. A later core probe can therefore see
a non-NULL rdev, skip rocket_device_init(), and dereference the error
pointer when reading rdev->num_cores.
Save the error code and clear rdev before returning from the
rocket_device_init() failure path. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/vc4: hdmi: Move packet RAM enable to PM runtime
Audio can be triggered by the HPD handler and start up before video has
been restored, calling vc4_hdmi_write_infoframe() for the audio infoframe.
vc4_hdmi_write_infoframe() needs Packet RAM to be on to store the
infoframe, however, if the video hasn't been enabled,
vc4_hdmi_encoder_post_crtc_enable() hasn't been called and therefore, the
Packet RAM can be disabled by the time vc4_hdmi_write_infoframe() executes,
causing the following splat:
[ 201.570266] ------------[ cut here ]------------
[ 201.570293] Packet RAM has to be on to store the packet.
[ 201.570367] WARNING: drivers/gpu/drm/vc4/vc4_hdmi.c:683 at vc4_hdmi_write_infoframe+0x404/0x494 [vc4], CPU#0: wireplumber/1606
[...]
[ 201.658650] Hardware name: Raspberry Pi 4 Model B Rev 1.5 (DT)
[...]
[ 201.758499] Call trace:
[ 201.760967] vc4_hdmi_write_infoframe+0x404/0x494 [vc4] (P)
[ 201.766607] vc4_hdmi_write_audio_infoframe+0x1c/0x28 [vc4]
[ 201.772247] write_infoframe+0xbc/0x140 [drm_display_helper]
[ 201.777975] drm_atomic_helper_connector_hdmi_update_audio_infoframe+0x80/0xdc [drm_display_helper]
[ 201.787140] vc4_hdmi_audio_prepare+0x4ac/0x570 [vc4]
[ 201.792252] drm_connector_hdmi_audio_prepare+0x24/0x30 [drm_display_helper]
[ 201.799390] hdmi_codec_prepare+0x100/0x160 [snd_soc_hdmi_codec]
[ 201.805471] snd_soc_pcm_dai_prepare+0xd4/0x100 [snd_soc_core]
[ 201.811375] __soc_pcm_prepare+0x60/0x12c [snd_soc_core]
[ 201.816752] soc_pcm_prepare+0x34/0x58 [snd_soc_core]
[ 201.821863] snd_pcm_do_prepare+0x70/0x8c [snd_pcm]
[ 201.826798] snd_pcm_action_nonatomic+0xe4/0x174 [snd_pcm]
[ 201.832350] snd_pcm_prepare+0xc8/0xd8 [snd_pcm]
[ 201.837021] snd_pcm_common_ioctl+0x458/0x614 [snd_pcm]
[ 201.842308] snd_pcm_ioctl+0x30/0x48 [snd_pcm]
[ 201.846802] __arm64_sys_ioctl+0x88/0xd8
[ 201.850769] invoke_syscall+0x48/0xf4
[ 201.854470] el0_svc_common+0x80/0xd8
[ 201.858171] do_el0_svc+0x1c/0x28
[ 201.861520] el0_svc+0x3c/0xb0
[ 201.864605] el0t_64_sync_handler+0x68/0xdc
[ 201.868834] el0t_64_sync+0x198/0x19c
[ 201.872536] ---[ end trace 0000000000000000 ]---
Considering that Packet RAM enable is essentially a power management
configuration, move its enabling/disabling to the Runtime PM hooks.
Note that post_crtc_disable() still stops all infoframes, but keeps Packet
RAM enabled, leaving it to be disabled by runtime suspend. |
| In the Linux kernel, the following vulnerability has been resolved:
power: supply: core: prevent unregistering a power supply while a callback runs
Once a power supply is registered, its callbacks can immediately start
firing from other contexts, such as external_power_changed() triggered by
the TCPM stack. If a power supply is unregistered while the callback is
still running, the driver data can already be freed when the callback
tries to access it, leading to a use-after-free.
This happens e.g. when the hardware bus carrying the power supply device
malfunctions (e.g. I2C is hogged down by another malfunctioning device)
immediately after the power supply is registered, and thus the core is
still processing the callbacks which were queued up when the driver
starts the removal, leading in some cases to a kernel crash, e.g.:
[ 11.645942] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000005
[ 11.646751] Mem abort info:
[ 11.647006] ESR = 0x0000000096000004
[ 11.647338] EC = 0x25: DABT (current EL), IL = 32 bits
[ 11.647806] SET = 0, FnV = 0
[ 11.648077] EA = 0, S1PTW = 0
[ 11.648356] FSC = 0x04: level 0 translation fault
[ 11.648785] Data abort info:
[ 11.649041] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
[ 11.649524] CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[ 11.649981] GCS = 0, Overlay = 0, DirtyBit = 0
[ 11.650390] [0000000000000005] user address but active_mm is swapper
[ 11.650955] Internal error: Oops: 0000000096000004 [#1] SMP
[ 11.651460] Modules linked in:
[ 11.651742] CPU: 1 UID: 0 PID: 144 Comm: kworker/1:2 Not tainted 7.2.0-rc6-g62a9297af2cd #1 PREEMPT
[ 11.652553] Hardware name: Flipper One rev. F0B1C2 (DT)
[ 11.653024] Workqueue: events power_supply_changed_work
[ 11.653511] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 11.654135] pc : __power_supply_is_supplied_by+0x18/0x100
[ 11.654624] lr : __power_supply_am_i_supplied+0x40/0xb8
[ 11.655098] sp : ffff80008192bb30
[ 11.655399] x29: ffff80008192bb30 x28: 0000000000000000 x27: 0000000000000000
[ 11.656049] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000
[ 11.656695] x23: ffff0000c19f4200 x22: ffffdb2232ba4ea8 x21: ffff80008192bc28
[ 11.657344] x20: ffff0000c1eef000 x19: ffff80008192bc18 x18: 00000000a0886e62
[ 11.657991] x17: 000000040044ffff x16: 04500072b5503510 x15: 0000000000000000
[ 11.658639] x14: 0000000000000000 x13: 0000000000000220 x12: 0000000000000000
[ 11.659286] x11: 0000000000000000 x10: ffff0000c1fdb2b0 x9 : ffffdb2232ba5590
[ 11.659934] x8 : 00000000e5b906e6 x7 : ffff0000c2502778 x6 : ffffdb22339793d0
[ 11.660581] x5 : ffff80008192bc18 x4 : ffff0000c19cbca0 x3 : 0000000000000000
[ 11.661228] x2 : ffff0000c1fdaf40 x1 : ffffffffffffffed x0 : ffff0000c1eef000
[ 11.661878] Call trace:
[ 11.662103] __power_supply_is_supplied_by+0x18/0x100 (P)
[ 11.662596] __power_supply_am_i_supplied+0x40/0xb8
[ 11.663040] psy_for_each_psy_cb+0x20/0x40
[ 11.663416] class_for_each_device+0x110/0x150
[ 11.663825] power_supply_am_i_supplied+0x68/0x100
[ 11.664262] bq257xx_external_power_changed+0x58/0x140
[ 11.664733] __power_supply_changed_work+0x60/0x80
[ 11.665170] psy_for_each_psy_cb+0x20/0x40
[ 11.665545] class_for_each_device+0x110/0x150
[ 11.665953] power_supply_changed_work+0x98/0x1b8
[ 11.666382] process_one_work+0x164/0x4c0
[ 11.666758] worker_thread+0x19c/0x320
[ 11.667104] kthread+0x138/0x150
[ 11.667408] ret_from_fork+0x10/0x20
[ 11.667744] Code: d503233f a9bd7bfd 910003fd a90153f3 (f9400c34)
[ 11.668294] ---[ end trace 0000000000000000 ]---
Add a read-write semaphore between external_power_changed() and
power_supply_unregister() to prevent the latter from returning (and thus
the driver from freeing its data) while the callback is still running. |
| In the Linux kernel, the following vulnerability has been resolved:
ksmbd: propagate DACL parsing errors
parse_dacl() silently accepts truncated ACEs and allocation failures,
allowing set_info_sec() to continue with an incomplete ACL conversion.
Return parsing and allocation errors to parse_sec_desc() so malformed
security descriptors are rejected before inode attributes or ACL xattrs
are updated. |
| 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:
cachefiles: Fix potential UAF/KASAN warning
Currently, trace_cachefiles_coherency() is being passed a pointer to a
__be64 lain over the coherency data in struct cachefiles_xattr so that it
can display the first 8 bytes. However, the data is of variable length and
could even be 0 bytes. This could lead to a UAF or KASAN warning.
Fix this by making sure the buffer has room for at least 8 bytes and that
those 8 bytes are pre-cleared.
Further, those bytes are not 8-byte aligned, so fix the tracepoint to
extract the data as four 2-byte words (they are 2-byte aligned) and
reassemble the __be64. The compiler will convert this into a single 8-byte
load where the CPU supports it. |
| In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix readahead synchronisation issues by loading all folios upfront
There are some synchronisation issues that derive from the app thread
adding more folios to the rolling buffer whilst the collector thread is
looking at them or trying to clear them, such as determining the setting of
front_folio_order when the next folio hasn't been added yet,
The reason for the rolling buffer approach is that loading the buffer
upfront and then dropping all the refs just acquired is quite a slow
operation, and loading progressively allows some of the cost to be deferred
until after at least some of the I/O is started.
Instead, a better way is to load all the folios into the rolling buffer
upfront - and then drop the refs later, once the I/O is in progress. (Even
better would be for the refs not to be there at all.)
Fix this by changing the rolling buffer loader to load all the folios
selected by the VM for readahead upfront into the folio queue. The folio
queue is allocated a batch worth at a time as we don't know how many folios
are involved (the readahead_control struct, alas, has a page count, not a
folio count).
The folio refs acquired from readahead are then dropped in bulk once the
first subrequest is dispatched as it's quite a slow operation. The
collector waits for NETFS_RREQ_NEED_PUT_RA_REFS to be cleared so that it
doesn't unlock folios before the xarray has been scanned for them.
This simplifies the buffer handling later and isn't noticeably slower as
the xarray doesn't need to be modified and the folios are all already
pre-locked. |
| In the Linux kernel, the following vulnerability has been resolved:
dm-integrity: fix infinite loop on discard with large tag size
When integrity_metadata handles a discard, it fills a buffer with
DISCARD_FILLER and writes it over the tags, max_blocks blocks at a
time. If the kmalloc fails, the buffer is the on-stack array
checksums_onstack and max_size is set to HASH_MAX_DIGESTSIZE. So if the
tag size is larger than HASH_MAX_DIGESTSIZE, max_blocks is zero, bi_size
is never decremented and the loop never terminates.
Fix this by using sizeof(checksums_onstack) as max_size. The array has
MAX_TAG_SIZE bytes since commit b93b6643e9b5 ("dm integrity: fix a
crash with unusually large tag size"), so max_blocks is at least 1. |
| In the Linux kernel, the following vulnerability has been resolved:
cifs: don't update i_size in cifs_do_truncate without a cached handle
If find_writable_file() returns null, cifs_file_flush will return
0 without issuing set_file_size, and the outer 'if (!rc)' block
will set i_size to 0 before telling the server to truncate. If
the cifs_open() then fails, the inode will have size 0, while
the server file is unchanged.
Move the netfs_resize_file() and cifs_setsize() into the 'if
(cfile)', so they only run after a successful set_file_size.
In the no-handle else branch, evict stale pages with
truncate_inode_pages before the O_TRUNC open to dispose of old
cache pages, and let the open response set the i_size. |
