| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| Exterro FTK Imager before 8.3 contains an XML external entity (XXE) injection vulnerability that allows attackers to read arbitrary files from the host filesystem by embedding malicious external entity references and attacker-controlled XSLT stylesheets within a Report.xml file inside a UFDR ZIP evidence item. Attackers can craft a malicious UFDR archive that, when previewed by an examiner, causes the XML parser to resolve file:// external entity references and execute msxsl:script within the external stylesheet to exfiltrate the resolved file contents to an attacker-controlled endpoint via a generated image URL. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/migrate: report RCU-tasks quiescent states in migrate_pages_batch()
migrate_pages_batch() unmaps each folio before moving it, and every
unmap runs the mmu_notifier invalidate callbacks. On KVM hosts
try_to_migrate() ends up in kvm_mmu_notifier_invalidate_range_start() ->
tdp_mmu_zap_leafs(), which is expensive, so unmapping a large batch keeps
the CPU busy for a long time.
The loop already calls cond_resched(), but on PREEMPTION kernels that is
a no-op, and involuntary preemption is not a Tasks-RCU quiescent state.
A long batch therefore never reports a quiescent state, and the
migrating task (e.g. kcompactd) becomes a Tasks-RCU holdout, stalling the
Tasks-RCU grace period for minutes, which is common at Meta fleet:
INFO: rcu_tasks detected stalls on tasks:
0000000055349ecc: .. nvcsw: 1157401/1157401 holdout: 1 idle_cpu: -1/56 task:kcompactd0 state:R running task
Call Trace:
tdp_mmu_zap_leafs
tdp_mmu_next_root
gfn_to_pfn_cache_invalidate_start
kvm_mmu_notifier_invalidate_range_start
__mmu_notifier_invalidate_range_start
try_to_migrate_one
try_to_migrate
migrate_pages_batch
migrate_pages
compact_zone
compact_node
kcompactd
kthread
Use cond_resched_tasks_rcu_qs() so a quiescent state is reported even
when cond_resched() does nothing.
This has also been discussed at [1] |
| In the Linux kernel, the following vulnerability has been resolved:
mm/vmscan: report RCU-tasks quiescent states in shrink_lruvec()
I am seeing some rcu_tasks stalls in the Meta fleet during reclaim.
INFO: rcu_tasks detected stalls on tasks:
0000000088620d09: .. nvcsw: 6735/6735 holdout: 1 idle_cpu: -1/8
task:GlobalCPUThread state:R running task pid:2552016 tgid:2524552
Call Trace:
shrink_lruvec
mem_cgroup_iter
shrink_node
do_try_to_free_pages
try_to_free_pages
__alloc_frozen_pages_noprof
alloc_pages_noprof
pte_alloc_one
__pte_alloc
handle_mm_fault
Nothing promises direct reclaim returns in bounded time, and the scan loop
in shrink_lruvec() only calls cond_resched(), which is a no-op on
PREEMPTION kernels. Involuntary preemption is not a Tasks-RCU quiescent
state, so the reclaiming task never reports one and becomes a holdout.
Upgrade it to cond_resched_tasks_rcu_qs(), which reports a quiescent state
even when cond_resched() does nothing.
PS: This has been discussed in [1] |
| In the Linux kernel, the following vulnerability has been resolved:
tracing/user_events: Clear copied tracing state before fork duplication
dup_task_struct() copies user_event_mm from the parent into the child,
without grabbing a reference to it. user_event_mm_dup() should
replace it, but it leaves that copied pointer unmodified if
user_event_mm_alloc() fails.
When the child exits, user_event_mm_remove() decrements a reference
the child never owned, which ultimately frees user_event_mm, while
the parent still as a stale pointer to it. This creates a UAF, which
KASAN reports as:
BUG: KASAN: slab-use-after-free in
current_user_event_mm+0x51/0x1d0 Write of size 4 at addr
ffff888005010d30 by task init/44
Call Trace:
<TASK>
kasan_report+0xce/0x100
kasan_check_range+0x10f/0x1e0
current_user_event_mm+0x51/0x1d0
user_events_ioctl+0x82e/0x15c0
__x64_sys_ioctl+0x139/0x1c0
do_syscall_64+0xce/0x450
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Allocated by task 44:
__kasan_kmalloc+0x8f/0xa0
__kmalloc_cache_noprof+0x180/0x3a0
user_event_mm_alloc+0x3c/0x1f0
current_user_event_mm+0x88/0x1d0
Freed by task 42:
__kasan_slab_free+0x43/0x70
kfree+0x13a/0x390
process_one_work+0x696/0xf90
worker_thread+0x420/0xba0
The fix simply clears the copied pointer before any possible failure.
In case of failure, the child then has nothing to free. |
| In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix use-after-free with same-name named triggers
When two hist triggers on different events are registered with the same
name=, the second one reuses the first as named_data. Both are added to
tr->hist_vars by save_hist_vars() during event_hist_trigger_parse(),
because save_hist_vars() is called before event_trigger_register() while
the named reuse is only detected later, in hist_register_trigger().
In the named-data branch hist_register_trigger() then frees the second
histogram's hist_data via destroy_hist_data(), but never removes its
tr->hist_vars list entry, leaving a dangling pointer and leaking the
trace_array reference it holds.
A later hist trigger that references a variable makes find_var_file()
walk tr->hist_vars and dereference the freed hist_data. The bug is
reproducible from userspace by writing three hist triggers to tracefs:
cd /sys/kernel/tracing
echo 'hist:keys=common_pid:x=common_pid:name=mh' > events/sched/sched_switch/trigger
echo 'hist:keys=common_pid:x=common_pid:name=mh' > events/sched/sched_process_fork/trigger
echo 'hist:keys=common_pid:vals=$x' > events/sched/sched_process_exit/trigger
The third write panics the kernel:
BUG: KASAN: slab-use-after-free in find_var_file.part.0+0x272/0x290
Read of size 8 at addr ffff888001f8a0e0 by task sh/1
CPU: 1 UID: 0 PID: 1 Comm: sh Tainted: G D N
Call Trace:
find_var_file.part.0
find_event_var
parse_atom
parse_expr
__create_val_field
event_hist_trigger_parse
trigger_process_regex
event_trigger_write
vfs_write
ksys_write
do_syscall_64
entry_SYSCALL_64_after_hwframe
Allocated by task 1:
event_hist_trigger_parse
Freed by task 1:
hist_register_trigger+0x618/0xa30
event_hist_trigger_parse
The buggy address belongs to freed 2048-byte region
Oops: general protection fault ... RIP: find_var_file.part.0
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
Fix by removing the hist_data from tr->hist_vars and releasing the
trace_array reference in the named-data branch of hist_register_trigger()
before freeing the hist_data. |
| In the Linux kernel, the following vulnerability has been resolved:
rapidio: mport_cdev: fix use-after-free in dma_req_free()
dma_req_free() acquires buf_mutex through req->map, drops the mapping
reference with kref_put(), and then dereferences req->map again to unlock
the mutex.
If kref_put() drops the last reference, mport_release_mapping() frees the
mapping, and the subsequent mutex_unlock() dereferences a freed object.
This is a use-after-free.
Fix this by caching map and md before kref_put(), clearing req->map while
holding buf_mutex, and using the cached md for mutex unlocking.
The bug is reachable from userspace via the RapidIO mport character device
interface. |
| In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: u_audio: Fix use-after-free on sound card disconnect
g_audio_cleanup() invokes snd_card_free_when_closed() to initiate sound
card teardown and immediately frees the underlying struct snd_uac_chip
context. However, snd_card_free_when_closed() returns asynchronously
while ALSA control elements (kctls) remain open in userspace.
When userspace control applications access or close these open file
descriptors, kctl callbacks attempt to dereference kctl->private_data
pointing to &uac->c_prm or &uac->p_prm within the freed uac structure,
resulting in a use-after-free (UAF) memory corruption.
Fix this issue by deferring the destruction of struct snd_uac_chip until
all references to the ALSA sound card are released. Register a custom
card->private_free callback (u_audio_card_free) during g_audio_setup()
that frees uac and its associated playback/capture request and ring
buffers only when the sound card reference count drops to zero. |
| In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: uvc: fix dangling pointers in uvc_function_bind() and uvc_function_unbind()
In uvc_function_bind() error path, we use usb_ep_free_request which
uses uvc->control_req but does not set it to NULL afterwards. Thus,
uvc->control_req is a dangling pointer causing a UAF. Also we do not set
the uvc->control_buf pointer to NULL after freeing it, which is another
dangling pointer. Fix it by setting uvc->control_req to NULL after we run
usb_ep_free_request() and uvc->control_buf to NULL after kfree. Do the
same for uvc_function_unbind(). |
| In the Linux kernel, the following vulnerability has been resolved:
NFSD: restart ssc_expire_umount walk after dropping nfsd_ssc_lock
nfsd4_ssc_expire_umount() walks nn->nfsd_ssc_mount_list with
list_for_each_entry_safe(ni, tmp, ...). For each expired entry it
sets nsui_busy = true, drops nfsd_ssc_lock to run mntput() on the
source vfsmount, then reacquires the lock to list_del + kfree the
entry and continue iterating via the macro's saved tmp pointer.
The nsui_busy flag protects the current ni from concurrent
nfsd4_ssc_setup_dul() finders during the lock-drop window, but it
does not pin tmp. Another nfsd RPC thread that fails its source-
server mount and reaches nfsd4_ssc_cancel_dul() will, during that
same window, take nfsd_ssc_lock, list_del + kfree its own ssc_umount
item, and release the lock. If that item is the saved tmp of the
expire walk, the next iteration dereferences a freed
nfsd4_ssc_umount_item.
Restart the walk from the head after the mntput() unlock window so
no saved next pointer survives the lock-drop. The list is bounded
by the number of active inter-server source mounts (typically small)
and the expire delayed-work runs periodically rather than per-IO,
so the restart is cheap. |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix cpntf publish race in nfs4_init_cp_state
nfs4_alloc_init_cpntf_state() published the new cpntf entry into the
s2s_cp_stateids IDR (with cs_type set) in one s2s_cp_lock section, then
took the lock again to list_add() it onto p_stid->sc_cp_list. In the gap
the entry is reachable by so_id but cp_list is still {NULL,NULL} from
kzalloc. A racing OFFLOAD_CANCEL (so_id is echoed to the client as
cnr_stateid, so any NFSv4.2 client can drive it) reaches
manage_cpntf_state() -> _free_cpntf_state_locked() and does list_del() on
the zeroed list_head, oopsing the server.
Fold the cs_type assignment and the list_add() into the same critical
section as idr_alloc_cyclic(), so a concurrent lookup either misses the
entry or sees a fully linked cp_list. INIT_LIST_HEAD() the entry after
allocation and switch _free_cpntf_state_locked() to list_del_init() so a
stale unlink is a no-op. nfs4_init_copy_state() passes NULL p_stid and
skips the list_add, preserving NFS4_COPY_STID semantics. |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: initialize copy-notify stateid before publishing it
nfsd4_copy_notify() finished initializing the cpntf state after
nfs4_alloc_init_cpntf_state() had already linked it into the
s2s_cp_stateids IDR and the parent's sc_cp_list, with cs_count == 1 (the
membership reference) and none held for the caller. A racing
OFFLOAD_CANCEL (crafted cl_id == nn->s2s_cp_cl_id plus the guessable
so_id) could reach manage_cpntf_state() and free the entry, turning the
caller's subsequent cpn_cnr_stateid read and cp_p_stateid/cp_p_clid
writes into use-after-free. The owning clientid was also only recorded
after publication, so it could not gate an ownership check in that window.
Record cp_p_stateid and cp_p_clid inside nfs4_alloc_init_cpntf_state()
before nfs4_init_cp_state() publishes the entry, and return it with an
extra reference. The caller reads the stateid under that reference and
drops it with nfs4_put_cpntf_state(); on a late error the laundromat
reaps the entry. |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: revoke copy-notify stateids before dropping their reference
Copy-notify stateids live in the s2s_cp_stateids IDR and on their parent
stid's sc_cp_list, pinned by a single membership reference.
_free_cpntf_state_locked() only unlinks an entry once its refcount reaches
zero, so any revoke path that runs while a concurrent
find_cpntf_state()/manage_cpntf_state() holder has elevated cs_count drops
the reference without unlinking, leaving the entry discoverable with its
membership reference already consumed. A second revoke or a laundromat tick
then frees it while the reader still holds the pointer -- a
KASAN-detectable use-after-free at the reader's nfs4_put_cpntf_state().
This affected all three revoke paths:
- The parent-stid drain (nfs4_free_cpntf_statelist()) repeatedly called
_free_cpntf_state_locked() on the first list entry; a holder that had
bumped cs_count made it return early, so the next iteration
re-decremented and burned the holder's reference.
- OFFLOAD_CANCEL (manage_cpntf_state()) and laundromat expiry likewise
used _free_cpntf_state_locked() and could drop 2->1 without unlinking.
Add revoke_cpntf_state_locked(), which unhashes the entry from the IDR and
sc_cp_list first (deferring the final free to any holder), and use it from
all three revoke paths. The drain now walks with list_for_each_entry_safe()
and revokes each entry unconditionally, so it terminates in one pass per
entry regardless of cs_count. The unhash is gated on
!list_empty(&cps->cp_list); the idr_remove() gate matters because
idr_alloc_cyclic() may have recycled the so_id by then. Keep
_free_cpntf_state_locked() for the reference-holder put path only, where a
concurrent revoke may already have unlinked the entry (its list_del_init()
then a no-op). |
| In the Linux kernel, the following vulnerability has been resolved:
HID: mcp2221: stop device IO before hid_hw_stop
Quiesce device IO at the start of the devm cleanup callback
mcp2221_hid_unregister() so that incoming HID reports cannot race with
hardware teardown during probe failure or device removal, addressing a
potential use-after-free.
Guard the call to hid_device_io_stop() with io_started. On normal
removal hid_device_remove() has already cleared io_started before the
devres group is released, so an unconditional call would otherwise hit
the !io_started path and emit a spurious "io already stopped" warning
on every removal. The guard preserves the probe-failure balancing,
where io_started is still set after hid_device_io_start(), while
staying silent on the normal removal path. |
| In the Linux kernel, the following vulnerability has been resolved:
eventfs: Initialize ei->children and ei->list in init_ei()
eventfs_create_dir() allocates the eventfs_inode and initializes it with
init_ei(). But this does not initialize the eventfs_inode list_heads. If
the eventfs_create_dir() fails due to memory pressure, it will call
free_ei() before it initialized the lists, and that checks to make sure
the eventfs_inode has no children. But because the list wasn't
initialized, it will give a false warning.
Fix it by moving the list initialization into init_ei().
[ Rewrote change log ] |
| In the Linux kernel, the following vulnerability has been resolved:
ecryptfs: hold msg ctx list lock when cleaning daemon queue
ecryptfs_exorcise_daemon() drops queued messages from a dying daemon
without holding ecryptfs_msg_ctx_lists_mux, but
ecryptfs_msg_ctx_alloc_to_free() requires that lock.
Take the list lock while moving the queued contexts back to the free
list to avoid racing with other global msg ctx list users. |
| In the Linux kernel, the following vulnerability has been resolved:
fbdev: ssd1307fb: defer I2C transfers from damage callbacks
The fbdev damage callbacks may run from fbcon while printk has disabled
preemption. They currently update the display synchronously, which enters
the sleeping I2C transfer path from atomic context.
A complete report from an RK3566 system follows:
[ 258.129004] watchdog: watchdog0: watchdog did not stop!
[ 258.129067] BUG: scheduling while atomic: systemd/1/0x00000003
[ 258.129076] Modules linked in: algif_hash algif_skcipher af_alg bnep
binfmt_misc lz4hc lz4 zram snd_soc_hdmi_codec brcmfmac_wcc hci_uart
fb_ssd1306(C) fbtft(C) btqca btrtl btintel btsdio snd_soc_simple_card
motorcomm pwm_fan snd_soc_simple_card_utils ssd130x_spi nls_iso8859_1
ssd130x btbcm drm_shmem_helper display_connector brcmfmac ssd1307fb
brcmutil bluetooth cfg80211 rfkill snd_soc_rockchip_i2s_tdm
snd_soc_rk817 hantro_vpu snd_soc_core snd_compress snd_pcm_dmaengine
v4l2_vp9 snd_pcm v4l2_h264 rockchip_rga snd_timer rk_crypto2
spi_rockchip_sfc videobuf2_dma_contig snd sm3_generic v4l2_mem2mem
videobuf2_dma_sg dwmac_rk sm3 soundcore videobuf2_memops videobuf2_v4l2
stmmac_platform dw_hdmi_cec videodev videobuf2_common dw_hdmi_i2s_audio
stmmac rk817_charger pcs_xpcs mc cpufreq_dt sch_fq_codel ip_tables
x_tables autofs4
[ 258.129215] Preemption disabled at:
[ 258.129216] [<ffff80008012f96c>] vprintk_emit+0x11c/0x340
[ 258.129234] CPU: 0 PID: 1 Comm: systemd Tainted: G C
6.6.0-rc5-rockchip-rk356x #4
[ 258.129239] Hardware name: Rockchip RK3566 OPi 3B (DT)
[ 258.129243] Call trace:
[ 258.129245] dump_backtrace+0xa0/0x128
[ 258.129252] show_stack+0x20/0x38
[ 258.129256] dump_stack_lvl+0x60/0xb0
[ 258.129265] dump_stack+0x18/0x28
[ 258.129269] __schedule_bug+0xa0/0xc8
[ 258.129274] __schedule+0x9ac/0xd30
[ 258.129279] schedule+0x60/0x100
[ 258.129282] schedule_timeout+0x194/0x338
[ 258.129289] rk3x_i2c_xfer_common.isra.0+0x384/0x498
[ 258.129296] rk3x_i2c_xfer+0x20/0x60
[ 258.129300] __i2c_transfer+0x194/0x648
[ 258.129308] i2c_transfer+0x9c/0x130
[ 258.129313] i2c_transfer_buffer_flags+0x64/0x98
[ 258.129318] ssd1307fb_update_rect+0x42c/0x560 [ssd1307fb]
[ 258.129334] ssd1307fb_defio_imageblit+0x34/0x50 [ssd1307fb]
[ 258.129343] soft_cursor+0x13c/0x210
[ 258.129350] bit_cursor+0x2dc/0x550
[ 258.129354] fbcon_cursor+0xec/0x108
[ 258.129359] hide_cursor+0x44/0xc8
[ 258.129365] vt_console_print+0x398/0x3b0
[ 258.129370] console_flush_all.isra.0+0x17c/0x410
[ 258.129377] console_unlock+0x4c/0x100
[ 258.129382] vprintk_emit+0x1c8/0x340
[ 258.129386] vprintk_default+0x40/0x58
[ 258.129389] vprintk+0xb8/0xd0
[ 258.129392] _printk+0x68/0x98
[ 258.129398] watchdog_release+0x170/0x230
[ 258.129404] __fput+0xbc/0x288
[ 258.129409] __fput_sync+0x58/0x70
[ 258.129413] __arm64_sys_close+0x40/0x90
[ 258.129419] invoke_syscall+0x4c/0x118
[ 258.129426] el0_svc_common.constprop.0+0x48/0xf0
[ 258.129432] do_el0_svc+0x24/0x38
[ 258.129437] el0_svc+0x48/0x100
[ 258.129443] el0t_64_sync_handler+0xc0/0xc8
[ 258.129448] el0t_64_sync+0x190/0x198
[ 258.573087] ------------[ cut here ]------------
[ 258.573098] DEBUG_LOCKS_WARN_ON(val > preempt_count())
[ 258.573111] WARNING: CPU: 0 PID: 1 at kernel/sched/core.c:5871
preempt_count_sub+0x9c/0x148
[ 258.573130] Modules linked in: algif_hash algif_skcipher af_alg bnep
binfmt_misc lz4hc lz4 zram snd_soc_hdmi_codec brcmfmac_wcc hci_uart
fb_ssd1306(C) fbtft(C) btqca btrtl btintel btsdio snd_soc_simple_card
motorcomm pwm_fan snd_soc_simple_card_utils ssd130x_spi nls_iso8859_1
ssd130x btbcm drm_shmem_helper display_connector brcmfmac ssd1307fb
brcmutil bluetooth cfg80211 rfkill snd_soc_rockchip_i2s_tdm
snd_soc_rk817 hantro_vpu snd_soc_core snd_compress snd_pcm_dmaengine
v4l2_vp
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
auxdisplay: charlcd: cancel backlight work on registration failure
With CONFIG_CHARLCD_BL_FLASH, charlcd_init() schedules bl_work before
charlcd_register() calls misc_register(). If registration fails, the
caller frees the charlcd object while delayed work still contains its
address.
Add charlcd_deinit() to cancel the delayed work and turn the backlight
off. Use it for both registration rollback and normal unregistration. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: core: Fill in DMA padding bytes in scsi_alloc_sgtables()
During fuzz testing, the following issue was discovered:
BUG: KMSAN: uninit-value in __dma_map_sg_attrs+0x217/0x310
__dma_map_sg_attrs+0x217/0x310
dma_map_sg_attrs+0x4a/0x70
ata_qc_issue+0x9f8/0x1420
__ata_scsi_queuecmd+0x1657/0x1740
ata_scsi_queuecmd+0x79a/0x920
scsi_queue_rq+0x4472/0x4f40
blk_mq_dispatch_rq_list+0x1cca/0x3ee0
__blk_mq_sched_dispatch_requests+0x458/0x630
blk_mq_sched_dispatch_requests+0x15b/0x340
__blk_mq_run_hw_queue+0xe5/0x250
__blk_mq_delay_run_hw_queue+0x138/0x780
blk_mq_run_hw_queue+0x4bb/0x7e0
blk_mq_sched_insert_request+0x2a7/0x4c0
blk_execute_rq+0x497/0x8a0
sg_io+0xbe0/0xe20
scsi_ioctl+0x2b36/0x3c60
sr_block_ioctl+0x319/0x440
blkdev_ioctl+0x80f/0xd70
__se_sys_ioctl+0x219/0x420
__x64_sys_ioctl+0x93/0xe0
x64_sys_call+0x1d6c/0x3ad0
do_syscall_64+0x4c/0xa0
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
Uninit was created at:
__alloc_pages+0x5c0/0xc80
alloc_pages+0xe0e/0x1050
blk_rq_map_user_iov+0x2b77/0x6100
blk_rq_map_user_io+0x2fa/0x4d0
sg_io+0xad6/0xe20
scsi_ioctl+0x2b36/0x3c60
sr_block_ioctl+0x319/0x440
blkdev_ioctl+0x80f/0xd70
__se_sys_ioctl+0x219/0x420
__x64_sys_ioctl+0x93/0xe0
x64_sys_call+0x1d6c/0x3ad0
do_syscall_64+0x4c/0xa0
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
Bytes 14-15 of 16 are uninitialized
Memory access of size 16 starts at ffff88800cbdb000
When processing the last unaligned element of the scatterlist, it is
supplemented with missing bytes in the amount of pad_len. These bytes
remain uninitialized, which leads to a problem.
Extend last_sg->length by pad_len first, then use sg_zero_buffer() to
zero those pad_len bytes. sg_zero_buffer() uses sg_miter internally,
which correctly handles sg entries spanning multiple pages and padding
that crosses a page boundary.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller. |
| In the Linux kernel, the following vulnerability has been resolved:
regulator: as3722_get_regulator_dt_data: fix premature of_node_put leaving dangling of_node pointer
In as3722_get_regulator_dt_data(), of_get_child_by_name() acquires a
reference on np, which is then assigned to pdev->dev.of_node. The
function immediately calls of_node_put(np), releasing the reference and
leaving pdev->dev.of_node as a dangling pointer.
Remove the of_node_put(np) call to let the device hold the reference. |
| In the Linux kernel, the following vulnerability has been resolved:
openrisc: fix arbitrary kernel memory access via or1k_atomic syscall
sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user
pointers, v1 and v2, and swaps the words they point to in hand-written
assembly.
l.lwz r29,0(r4)
l.lwz r27,0(r5)
l.sw 0(r4),r27
l.sw 0(r5),r29
The pointers are not checked with access_ok(). The four memory
accesses also have no exception table entries.
A caller passes a kernel address as either pointer, and the syscall
reads from and writes to it directly.
This gives an unprivileged process a kernel read/write primitive. It
overwrites kernel data such as the sys_call_table, gaining code
execution in kernel context.
Check both pointers before entering the critical section. Add fixups
for the four memory accesses so faults on valid but unmapped user
addresses return -EFAULT.
[shorne@gmail.com: fix comment style] |
