In the Linux kernel, the following vulnerability has been resolved:
maple_tree: fix MA_STATE_PREALLOC flag in mas_preallocate()
Temporarily clear the preallocation flag when explicitly requesting
allocations. Pre-existing allocations are already counted against the
request through mas_node_count_gfp(), but the allocations will not happen
if the MA_STATE_PREALLOC flag is set. This flag is meant to avoid
re-allocating in bulk allocation mode, and to detect issues with
preallocation calculations.
The MA_STATE_PREALLOC flag should also always be set on zero allocations
so that detection of underflow allocations will print a WARN_ON() during
consumption.
User visible effect of this flaw is a WARN_ON() followed by a null pointer
dereference when subsequent requests for larger number of nodes is
ignored, such as the vma merge retry in mmap_region() caused by drivers
altering the vma flags (which happens in v6.6, at least)
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix a race between renames and directory logging
We have a race between a rename and directory inode logging that if it
happens and we crash/power fail before the rename completes, the next time
the filesystem is mounted, the log replay code will end up deleting the
file that was being renamed.
This is best explained following a step by step analysis of an interleaving
of steps that lead into this situation.
Consider the initial conditions:
1) We are at transaction N;
2) We have directories A and B created in a past transaction (< N);
3) We have inode X corresponding to a file that has 2 hardlinks, one in
directory A and the other in directory B, so we'll name them as
"A/foo_link1" and "B/foo_link2". Both hard links were persisted in a
past transaction (< N);
4) We have inode Y corresponding to a file that as a single hard link and
is located in directory A, we'll name it as "A/bar". This file was also
persisted in a past transaction (< N).
The steps leading to a file loss are the following and for all of them we
are under transaction N:
1) Link "A/foo_link1" is removed, so inode's X last_unlink_trans field
is updated to N, through btrfs_unlink() -> btrfs_record_unlink_dir();
2) Task A starts a rename for inode Y, with the goal of renaming from
"A/bar" to "A/baz", so we enter btrfs_rename();
3) Task A inserts the new BTRFS_INODE_REF_KEY for inode Y by calling
btrfs_insert_inode_ref();
4) Because the rename happens in the same directory, we don't set the
last_unlink_trans field of directoty A's inode to the current
transaction id, that is, we don't cal btrfs_record_unlink_dir();
5) Task A then removes the entries from directory A (BTRFS_DIR_ITEM_KEY
and BTRFS_DIR_INDEX_KEY items) when calling __btrfs_unlink_inode()
(actually the dir index item is added as a delayed item, but the
effect is the same);
6) Now before task A adds the new entry "A/baz" to directory A by
calling btrfs_add_link(), another task, task B is logging inode X;
7) Task B starts a fsync of inode X and after logging inode X, at
btrfs_log_inode_parent() it calls btrfs_log_all_parents(), since
inode X has a last_unlink_trans value of N, set at in step 1;
8) At btrfs_log_all_parents() we search for all parent directories of
inode X using the commit root, so we find directories A and B and log
them. Bu when logging direct A, we don't have a dir index item for
inode Y anymore, neither the old name "A/bar" nor for the new name
"A/baz" since the rename has deleted the old name but has not yet
inserted the new name - task A hasn't called yet btrfs_add_link() to
do that.
Note that logging directory A doesn't fallback to a transaction
commit because its last_unlink_trans has a lower value than the
current transaction's id (see step 4);
9) Task B finishes logging directories A and B and gets back to
btrfs_sync_file() where it calls btrfs_sync_log() to persist the log
tree;
10) Task B successfully persisted the log tree, btrfs_sync_log() completed
with success, and a power failure happened.
We have a log tree without any directory entry for inode Y, so the
log replay code deletes the entry for inode Y, name "A/bar", from the
subvolume tree since it doesn't exist in the log tree and the log
tree is authorative for its index (we logged a BTRFS_DIR_LOG_INDEX_KEY
item that covers the index range for the dentry that corresponds to
"A/bar").
Since there's no other hard link for inode Y and the log replay code
deletes the name "A/bar", the file is lost.
The issue wouldn't happen if task B synced the log only after task A
called btrfs_log_new_name(), which would update the log with the new name
for inode Y ("A/bar").
Fix this by pinning the log root during renames before removing the old
directory entry, and unpinning af
---truncated---
In the Linux kernel, the following vulnerability has been resolved:
drm/msm/gpu: Fix crash when throttling GPU immediately during boot
There is a small chance that the GPU is already hot during boot. In that
case, the call to of_devfreq_cooling_register() will immediately try to
apply devfreq cooling, as seen in the following crash:
Unable to handle kernel paging request at virtual address 0000000000014110
pc : a6xx_gpu_busy+0x1c/0x58 [msm]
lr : msm_devfreq_get_dev_status+0xbc/0x140 [msm]
Call trace:
a6xx_gpu_busy+0x1c/0x58 [msm] (P)
devfreq_simple_ondemand_func+0x3c/0x150
devfreq_update_target+0x44/0xd8
qos_max_notifier_call+0x30/0x84
blocking_notifier_call_chain+0x6c/0xa0
pm_qos_update_target+0xd0/0x110
freq_qos_apply+0x3c/0x74
apply_constraint+0x88/0x148
__dev_pm_qos_update_request+0x7c/0xcc
dev_pm_qos_update_request+0x38/0x5c
devfreq_cooling_set_cur_state+0x98/0xf0
__thermal_cdev_update+0x64/0xb4
thermal_cdev_update+0x4c/0x58
step_wise_manage+0x1f0/0x318
__thermal_zone_device_update+0x278/0x424
__thermal_cooling_device_register+0x2bc/0x308
thermal_of_cooling_device_register+0x10/0x1c
of_devfreq_cooling_register_power+0x240/0x2bc
of_devfreq_cooling_register+0x14/0x20
msm_devfreq_init+0xc4/0x1a0 [msm]
msm_gpu_init+0x304/0x574 [msm]
adreno_gpu_init+0x1c4/0x2e0 [msm]
a6xx_gpu_init+0x5c8/0x9c8 [msm]
adreno_bind+0x2a8/0x33c [msm]
...
At this point we haven't initialized the GMU at all yet, so we cannot read
the GMU registers inside a6xx_gpu_busy(). A similar issue was fixed before
in commit 6694482a70e9 ("drm/msm: Avoid unclocked GMU register access in
6xx gpu_busy"): msm_devfreq_init() does call devfreq_suspend_device(), but
unlike msm_devfreq_suspend(), it doesn't set the df->suspended flag
accordingly. This means the df->suspended flag does not match the actual
devfreq state after initialization and msm_devfreq_get_dev_status() will
end up accessing GMU registers, causing the crash.
Fix this by setting df->suspended correctly during initialization.
Patchwork: https://patchwork.freedesktop.org/patch/650772/
In the Linux kernel, the following vulnerability has been resolved:
posix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del()
If an exiting non-autoreaping task has already passed exit_notify() and
calls handle_posix_cpu_timers() from IRQ, it can be reaped by its parent
or debugger right after unlock_task_sighand().
If a concurrent posix_cpu_timer_del() runs at that moment, it won't be
able to detect timer->it.cpu.firing != 0: cpu_timer_task_rcu() and/or
lock_task_sighand() will fail.
Add the tsk->exit_state check into run_posix_cpu_timers() to fix this.
This fix is not needed if CONFIG_POSIX_CPU_TIMERS_TASK_WORK=y, because
exit_task_work() is called before exit_notify(). But the check still
makes sense, task_work_add(&tsk->posix_cputimers_work.work) will fail
anyway in this case.
In the Linux kernel, the following vulnerability has been resolved:
net/sched: Always pass notifications when child class becomes empty
Certain classful qdiscs may invoke their classes' dequeue handler on an
enqueue operation. This may unexpectedly empty the child qdisc and thus
make an in-flight class passive via qlen_notify(). Most qdiscs do not
expect such behaviour at this point in time and may re-activate the
class eventually anyways which will lead to a use-after-free.
The referenced fix commit attempted to fix this behavior for the HFSC
case by moving the backlog accounting around, though this turned out to
be incomplete since the parent's parent may run into the issue too.
The following reproducer demonstrates this use-after-free:
tc qdisc add dev lo root handle 1: drr
tc filter add dev lo parent 1: basic classid 1:1
tc class add dev lo parent 1: classid 1:1 drr
tc qdisc add dev lo parent 1:1 handle 2: hfsc def 1
tc class add dev lo parent 2: classid 2:1 hfsc rt m1 8 d 1 m2 0
tc qdisc add dev lo parent 2:1 handle 3: netem
tc qdisc add dev lo parent 3:1 handle 4: blackhole
echo 1 | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888
tc class delete dev lo classid 1:1
echo 1 | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888
Since backlog accounting issues leading to a use-after-frees on stale
class pointers is a recurring pattern at this point, this patch takes
a different approach. Instead of trying to fix the accounting, the patch
ensures that qdisc_tree_reduce_backlog always calls qlen_notify when
the child qdisc is empty. This solves the problem because deletion of
qdiscs always involves a call to qdisc_reset() and / or
qdisc_purge_queue() which ultimately resets its qlen to 0 thus causing
the following qdisc_tree_reduce_backlog() to report to the parent. Note
that this may call qlen_notify on passive classes multiple times. This
is not a problem after the recent patch series that made all the
classful qdiscs qlen_notify() handlers idempotent.
Insufficient validation of untrusted input in ANGLE and GPU in Google Chrome prior to 138.0.7204.157 allowed a remote attacker to potentially perform a sandbox escape via a crafted HTML page. (Chromium security severity: High)
In the Linux kernel, the following vulnerability has been resolved:
software node: Correct a OOB check in software_node_get_reference_args()
software_node_get_reference_args() wants to get @index-th element, so
the property value requires at least '(index + 1) * sizeof(*ref)' bytes
but that can not be guaranteed by current OOB check, and may cause OOB
for malformed property.
Fix by using as OOB check '((index + 1) * sizeof(*ref) > prop->length)'.
In the Linux kernel, the following vulnerability has been resolved:
ACPICA: fix acpi operand cache leak in dswstate.c
ACPICA commit 987a3b5cf7175916e2a4b6ea5b8e70f830dfe732
I found an ACPI cache leak in ACPI early termination and boot continuing case.
When early termination occurs due to malicious ACPI table, Linux kernel
terminates ACPI function and continues to boot process. While kernel terminates
ACPI function, kmem_cache_destroy() reports Acpi-Operand cache leak.
Boot log of ACPI operand cache leak is as follows:
>[ 0.585957] ACPI: Added _OSI(Module Device)
>[ 0.587218] ACPI: Added _OSI(Processor Device)
>[ 0.588530] ACPI: Added _OSI(3.0 _SCP Extensions)
>[ 0.589790] ACPI: Added _OSI(Processor Aggregator Device)
>[ 0.591534] ACPI Error: Illegal I/O port address/length above 64K: C806E00000004002/0x2 (20170303/hwvalid-155)
>[ 0.594351] ACPI Exception: AE_LIMIT, Unable to initialize fixed events (20170303/evevent-88)
>[ 0.597858] ACPI: Unable to start the ACPI Interpreter
>[ 0.599162] ACPI Error: Could not remove SCI handler (20170303/evmisc-281)
>[ 0.601836] kmem_cache_destroy Acpi-Operand: Slab cache still has objects
>[ 0.603556] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.12.0-rc5 #26
>[ 0.605159] Hardware name: innotek gmb_h virtual_box/virtual_box, BIOS virtual_box 12/01/2006
>[ 0.609177] Call Trace:
>[ 0.610063] ? dump_stack+0x5c/0x81
>[ 0.611118] ? kmem_cache_destroy+0x1aa/0x1c0
>[ 0.612632] ? acpi_sleep_proc_init+0x27/0x27
>[ 0.613906] ? acpi_os_delete_cache+0xa/0x10
>[ 0.617986] ? acpi_ut_delete_caches+0x3f/0x7b
>[ 0.619293] ? acpi_terminate+0xa/0x14
>[ 0.620394] ? acpi_init+0x2af/0x34f
>[ 0.621616] ? __class_create+0x4c/0x80
>[ 0.623412] ? video_setup+0x7f/0x7f
>[ 0.624585] ? acpi_sleep_proc_init+0x27/0x27
>[ 0.625861] ? do_one_initcall+0x4e/0x1a0
>[ 0.627513] ? kernel_init_freeable+0x19e/0x21f
>[ 0.628972] ? rest_init+0x80/0x80
>[ 0.630043] ? kernel_init+0xa/0x100
>[ 0.631084] ? ret_from_fork+0x25/0x30
>[ 0.633343] vgaarb: loaded
>[ 0.635036] EDAC MC: Ver: 3.0.0
>[ 0.638601] PCI: Probing PCI hardware
>[ 0.639833] PCI host bridge to bus 0000:00
>[ 0.641031] pci_bus 0000:00: root bus resource [io 0x0000-0xffff]
> ... Continue to boot and log is omitted ...
I analyzed this memory leak in detail and found acpi_ds_obj_stack_pop_and_
delete() function miscalculated the top of the stack. acpi_ds_obj_stack_push()
function uses walk_state->operand_index for start position of the top, but
acpi_ds_obj_stack_pop_and_delete() function considers index 0 for it.
Therefore, this causes acpi operand memory leak.
This cache leak causes a security threat because an old kernel (<= 4.9) shows
memory locations of kernel functions in stack dump. Some malicious users
could use this information to neutralize kernel ASLR.
I made a patch to fix ACPI operand cache leak.
In the Linux kernel, the following vulnerability has been resolved:
ftrace: Fix UAF when lookup kallsym after ftrace disabled
The following issue happens with a buggy module:
BUG: unable to handle page fault for address: ffffffffc05d0218
PGD 1bd66f067 P4D 1bd66f067 PUD 1bd671067 PMD 101808067 PTE 0
Oops: Oops: 0000 [#1] SMP KASAN PTI
Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
RIP: 0010:sized_strscpy+0x81/0x2f0
RSP: 0018:ffff88812d76fa08 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffffc0601010 RCX: dffffc0000000000
RDX: 0000000000000038 RSI: dffffc0000000000 RDI: ffff88812608da2d
RBP: 8080808080808080 R08: ffff88812608da2d R09: ffff88812608da68
R10: ffff88812608d82d R11: ffff88812608d810 R12: 0000000000000038
R13: ffff88812608da2d R14: ffffffffc05d0218 R15: fefefefefefefeff
FS: 00007fef552de740(0000) GS:ffff8884251c7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffc05d0218 CR3: 00000001146f0000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
ftrace_mod_get_kallsym+0x1ac/0x590
update_iter_mod+0x239/0x5b0
s_next+0x5b/0xa0
seq_read_iter+0x8c9/0x1070
seq_read+0x249/0x3b0
proc_reg_read+0x1b0/0x280
vfs_read+0x17f/0x920
ksys_read+0xf3/0x1c0
do_syscall_64+0x5f/0x2e0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
The above issue may happen as follows:
(1) Add kprobe tracepoint;
(2) insmod test.ko;
(3) Module triggers ftrace disabled;
(4) rmmod test.ko;
(5) cat /proc/kallsyms; --> Will trigger UAF as test.ko already removed;
ftrace_mod_get_kallsym()
...
strscpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
...
The problem is when a module triggers an issue with ftrace and
sets ftrace_disable. The ftrace_disable is set when an anomaly is
discovered and to prevent any more damage, ftrace stops all text
modification. The issue that happened was that the ftrace_disable stops
more than just the text modification.
When a module is loaded, its init functions can also be traced. Because
kallsyms deletes the init functions after a module has loaded, ftrace
saves them when the module is loaded and function tracing is enabled. This
allows the output of the function trace to show the init function names
instead of just their raw memory addresses.
When a module is removed, ftrace_release_mod() is called, and if
ftrace_disable is set, it just returns without doing anything more. The
problem here is that it leaves the mod_list still around and if kallsyms
is called, it will call into this code and access the module memory that
has already been freed as it will return:
strscpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
Where the "mod" no longer exists and triggers a UAF bug.