| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
drm/mgag200: Bind I2C lifetime to DRM device
Managed cleanup with devm_add_action_or_reset() will release the I2C
adapter when the underlying Linux device goes away. But the connector
still refers to it, so this cleanup leaves behind a stale pointer
in struct drm_connector.ddc.
Bind the lifetime of the I2C adapter to the connector's lifetime by
using DRM's managed release. When the DRM device goes away (after
the Linux device) DRM will first clean up the connector and then
clean up the I2C adapter. |
| In the Linux kernel, the following vulnerability has been resolved:
kcm: Serialise kcm_sendmsg() for the same socket.
syzkaller reported UAF in kcm_release(). [0]
The scenario is
1. Thread A builds a skb with MSG_MORE and sets kcm->seq_skb.
2. Thread A resumes building skb from kcm->seq_skb but is blocked
by sk_stream_wait_memory()
3. Thread B calls sendmsg() concurrently, finishes building kcm->seq_skb
and puts the skb to the write queue
4. Thread A faces an error and finally frees skb that is already in the
write queue
5. kcm_release() does double-free the skb in the write queue
When a thread is building a MSG_MORE skb, another thread must not touch it.
Let's add a per-sk mutex and serialise kcm_sendmsg().
[0]:
BUG: KASAN: slab-use-after-free in __skb_unlink include/linux/skbuff.h:2366 [inline]
BUG: KASAN: slab-use-after-free in __skb_dequeue include/linux/skbuff.h:2385 [inline]
BUG: KASAN: slab-use-after-free in __skb_queue_purge_reason include/linux/skbuff.h:3175 [inline]
BUG: KASAN: slab-use-after-free in __skb_queue_purge include/linux/skbuff.h:3181 [inline]
BUG: KASAN: slab-use-after-free in kcm_release+0x170/0x4c8 net/kcm/kcmsock.c:1691
Read of size 8 at addr ffff0000ced0fc80 by task syz-executor329/6167
CPU: 1 PID: 6167 Comm: syz-executor329 Tainted: G B 6.8.0-rc5-syzkaller-g9abbc24128bc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call trace:
dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:291
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:298
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x178/0x518 mm/kasan/report.c:488
kasan_report+0xd8/0x138 mm/kasan/report.c:601
__asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381
__skb_unlink include/linux/skbuff.h:2366 [inline]
__skb_dequeue include/linux/skbuff.h:2385 [inline]
__skb_queue_purge_reason include/linux/skbuff.h:3175 [inline]
__skb_queue_purge include/linux/skbuff.h:3181 [inline]
kcm_release+0x170/0x4c8 net/kcm/kcmsock.c:1691
__sock_release net/socket.c:659 [inline]
sock_close+0xa4/0x1e8 net/socket.c:1421
__fput+0x30c/0x738 fs/file_table.c:376
____fput+0x20/0x30 fs/file_table.c:404
task_work_run+0x230/0x2e0 kernel/task_work.c:180
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0x618/0x1f64 kernel/exit.c:871
do_group_exit+0x194/0x22c kernel/exit.c:1020
get_signal+0x1500/0x15ec kernel/signal.c:2893
do_signal+0x23c/0x3b44 arch/arm64/kernel/signal.c:1249
do_notify_resume+0x74/0x1f4 arch/arm64/kernel/entry-common.c:148
exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]
exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]
el0_svc+0xac/0x168 arch/arm64/kernel/entry-common.c:713
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
Allocated by task 6166:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x40/0x78 mm/kasan/common.c:68
kasan_save_alloc_info+0x70/0x84 mm/kasan/generic.c:626
unpoison_slab_object mm/kasan/common.c:314 [inline]
__kasan_slab_alloc+0x74/0x8c mm/kasan/common.c:340
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3813 [inline]
slab_alloc_node mm/slub.c:3860 [inline]
kmem_cache_alloc_node+0x204/0x4c0 mm/slub.c:3903
__alloc_skb+0x19c/0x3d8 net/core/skbuff.c:641
alloc_skb include/linux/skbuff.h:1296 [inline]
kcm_sendmsg+0x1d3c/0x2124 net/kcm/kcmsock.c:783
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
sock_sendmsg+0x220/0x2c0 net/socket.c:768
splice_to_socket+0x7cc/0xd58 fs/splice.c:889
do_splice_from fs/splice.c:941 [inline]
direct_splice_actor+0xec/0x1d8 fs/splice.c:1164
splice_direct_to_actor+0x438/0xa0c fs/splice.c:1108
do_splice_direct_actor
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
net: bridge: mcast: wait for previous gc cycles when removing port
syzbot hit a use-after-free[1] which is caused because the bridge doesn't
make sure that all previous garbage has been collected when removing a
port. What happens is:
CPU 1 CPU 2
start gc cycle remove port
acquire gc lock first
wait for lock
call br_multicasg_gc() directly
acquire lock now but free port
the port can be freed
while grp timers still
running
Make sure all previous gc cycles have finished by using flush_work before
freeing the port.
[1]
BUG: KASAN: slab-use-after-free in br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861
Read of size 8 at addr ffff888071d6d000 by task syz.5.1232/9699
CPU: 1 PID: 9699 Comm: syz.5.1232 Not tainted 6.10.0-rc5-syzkaller-00021-g24ca36a562d6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc3/0x620 mm/kasan/report.c:488
kasan_report+0xd9/0x110 mm/kasan/report.c:601
br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861
call_timer_fn+0x1a3/0x610 kernel/time/timer.c:1792
expire_timers kernel/time/timer.c:1843 [inline]
__run_timers+0x74b/0xaf0 kernel/time/timer.c:2417
__run_timer_base kernel/time/timer.c:2428 [inline]
__run_timer_base kernel/time/timer.c:2421 [inline]
run_timer_base+0x111/0x190 kernel/time/timer.c:2437 |
| In the Linux kernel, the following vulnerability has been resolved:
cgroup/cpuset: Prevent UAF in proc_cpuset_show()
An UAF can happen when /proc/cpuset is read as reported in [1].
This can be reproduced by the following methods:
1.add an mdelay(1000) before acquiring the cgroup_lock In the
cgroup_path_ns function.
2.$cat /proc/<pid>/cpuset repeatly.
3.$mount -t cgroup -o cpuset cpuset /sys/fs/cgroup/cpuset/
$umount /sys/fs/cgroup/cpuset/ repeatly.
The race that cause this bug can be shown as below:
(umount) | (cat /proc/<pid>/cpuset)
css_release | proc_cpuset_show
css_release_work_fn | css = task_get_css(tsk, cpuset_cgrp_id);
css_free_rwork_fn | cgroup_path_ns(css->cgroup, ...);
cgroup_destroy_root | mutex_lock(&cgroup_mutex);
rebind_subsystems |
cgroup_free_root |
| // cgrp was freed, UAF
| cgroup_path_ns_locked(cgrp,..);
When the cpuset is initialized, the root node top_cpuset.css.cgrp
will point to &cgrp_dfl_root.cgrp. In cgroup v1, the mount operation will
allocate cgroup_root, and top_cpuset.css.cgrp will point to the allocated
&cgroup_root.cgrp. When the umount operation is executed,
top_cpuset.css.cgrp will be rebound to &cgrp_dfl_root.cgrp.
The problem is that when rebinding to cgrp_dfl_root, there are cases
where the cgroup_root allocated by setting up the root for cgroup v1
is cached. This could lead to a Use-After-Free (UAF) if it is
subsequently freed. The descendant cgroups of cgroup v1 can only be
freed after the css is released. However, the css of the root will never
be released, yet the cgroup_root should be freed when it is unmounted.
This means that obtaining a reference to the css of the root does
not guarantee that css.cgrp->root will not be freed.
Fix this problem by using rcu_read_lock in proc_cpuset_show().
As cgroup_root is kfree_rcu after commit d23b5c577715
("cgroup: Make operations on the cgroup root_list RCU safe"),
css->cgroup won't be freed during the critical section.
To call cgroup_path_ns_locked, css_set_lock is needed, so it is safe to
replace task_get_css with task_css.
[1] https://syzkaller.appspot.com/bug?extid=9b1ff7be974a403aa4cd |
| In the Linux kernel, the following vulnerability has been resolved:
leds: trigger: Unregister sysfs attributes before calling deactivate()
Triggers which have trigger specific sysfs attributes typically store
related data in trigger-data allocated by the activate() callback and
freed by the deactivate() callback.
Calling device_remove_groups() after calling deactivate() leaves a window
where the sysfs attributes show/store functions could be called after
deactivation and then operate on the just freed trigger-data.
Move the device_remove_groups() call to before deactivate() to close
this race window.
This also makes the deactivation path properly do things in reverse order
of the activation path which calls the activate() callback before calling
device_add_groups(). |
| In the src/libs/zbxembed/browser.c file, the es_browser_ctor method retrieves a heap pointer from the Duktape JavaScript engine. This heap pointer is subsequently utilized by the browser_push_error method in the src/libs/zbxembed/browser_error.c file. A use-after-free bug can occur at this stage if the wd->browser heap pointer is freed by garbage collection. |
| In the Linux kernel, the following vulnerability has been resolved:
media: venus: fix use after free in vdec_close
There appears to be a possible use after free with vdec_close().
The firmware will add buffer release work to the work queue through
HFI callbacks as a normal part of decoding. Randomly closing the
decoder device from userspace during normal decoding can incur
a read after free for inst.
Fix it by cancelling the work in vdec_close. |
| In the Linux kernel, the following vulnerability has been resolved:
RDMA/iwcm: Fix a use-after-free related to destroying CM IDs
iw_conn_req_handler() associates a new struct rdma_id_private (conn_id) with
an existing struct iw_cm_id (cm_id) as follows:
conn_id->cm_id.iw = cm_id;
cm_id->context = conn_id;
cm_id->cm_handler = cma_iw_handler;
rdma_destroy_id() frees both the cm_id and the struct rdma_id_private. Make
sure that cm_work_handler() does not trigger a use-after-free by only
freeing of the struct rdma_id_private after all pending work has finished. |
| In the Linux kernel, the following vulnerability has been resolved:
mISDN: Fix a use after free in hfcmulti_tx()
Don't dereference *sp after calling dev_kfree_skb(*sp). |
| In the Linux kernel, the following vulnerability has been resolved:
net/iucv: fix use after free in iucv_sock_close()
iucv_sever_path() is called from process context and from bh context.
iucv->path is used as indicator whether somebody else is taking care of
severing the path (or it is already removed / never existed).
This needs to be done with atomic compare and swap, otherwise there is a
small window where iucv_sock_close() will try to work with a path that has
already been severed and freed by iucv_callback_connrej() called by
iucv_tasklet_fn().
Example:
[452744.123844] Call Trace:
[452744.123845] ([<0000001e87f03880>] 0x1e87f03880)
[452744.123966] [<00000000d593001e>] iucv_path_sever+0x96/0x138
[452744.124330] [<000003ff801ddbca>] iucv_sever_path+0xc2/0xd0 [af_iucv]
[452744.124336] [<000003ff801e01b6>] iucv_sock_close+0xa6/0x310 [af_iucv]
[452744.124341] [<000003ff801e08cc>] iucv_sock_release+0x3c/0xd0 [af_iucv]
[452744.124345] [<00000000d574794e>] __sock_release+0x5e/0xe8
[452744.124815] [<00000000d5747a0c>] sock_close+0x34/0x48
[452744.124820] [<00000000d5421642>] __fput+0xba/0x268
[452744.124826] [<00000000d51b382c>] task_work_run+0xbc/0xf0
[452744.124832] [<00000000d5145710>] do_notify_resume+0x88/0x90
[452744.124841] [<00000000d5978096>] system_call+0xe2/0x2c8
[452744.125319] Last Breaking-Event-Address:
[452744.125321] [<00000000d5930018>] iucv_path_sever+0x90/0x138
[452744.125324]
[452744.125325] Kernel panic - not syncing: Fatal exception in interrupt
Note that bh_lock_sock() is not serializing the tasklet context against
process context, because the check for sock_owned_by_user() and
corresponding handling is missing.
Ideas for a future clean-up patch:
A) Correct usage of bh_lock_sock() in tasklet context, as described in
Re-enqueue, if needed. This may require adding return values to the
tasklet functions and thus changes to all users of iucv.
B) Change iucv tasklet into worker and use only lock_sock() in af_iucv. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_tables: unconditionally flush pending work before notifier
syzbot reports:
KASAN: slab-uaf in nft_ctx_update include/net/netfilter/nf_tables.h:1831
KASAN: slab-uaf in nft_commit_release net/netfilter/nf_tables_api.c:9530
KASAN: slab-uaf int nf_tables_trans_destroy_work+0x152b/0x1750 net/netfilter/nf_tables_api.c:9597
Read of size 2 at addr ffff88802b0051c4 by task kworker/1:1/45
[..]
Workqueue: events nf_tables_trans_destroy_work
Call Trace:
nft_ctx_update include/net/netfilter/nf_tables.h:1831 [inline]
nft_commit_release net/netfilter/nf_tables_api.c:9530 [inline]
nf_tables_trans_destroy_work+0x152b/0x1750 net/netfilter/nf_tables_api.c:9597
Problem is that the notifier does a conditional flush, but its possible
that the table-to-be-removed is still referenced by transactions being
processed by the worker, so we need to flush unconditionally.
We could make the flush_work depend on whether we found a table to delete
in nf-next to avoid the flush for most cases.
AFAICS this problem is only exposed in nf-next, with
commit e169285f8c56 ("netfilter: nf_tables: do not store nft_ctx in transaction objects"),
with this commit applied there is an unconditional fetch of
table->family which is whats triggering the above splat. |
| In the Linux kernel, the following vulnerability has been resolved:
mlxsw: spectrum_buffers: Fix memory corruptions on Spectrum-4 systems
The following two shared buffer operations make use of the Shared Buffer
Status Register (SBSR):
# devlink sb occupancy snapshot pci/0000:01:00.0
# devlink sb occupancy clearmax pci/0000:01:00.0
The register has two masks of 256 bits to denote on which ingress /
egress ports the register should operate on. Spectrum-4 has more than
256 ports, so the register was extended by cited commit with a new
'port_page' field.
However, when filling the register's payload, the driver specifies the
ports as absolute numbers and not relative to the first port of the port
page, resulting in memory corruptions [1].
Fix by specifying the ports relative to the first port of the port page.
[1]
BUG: KASAN: slab-use-after-free in mlxsw_sp_sb_occ_snapshot+0xb6d/0xbc0
Read of size 1 at addr ffff8881068cb00f by task devlink/1566
[...]
Call Trace:
<TASK>
dump_stack_lvl+0xc6/0x120
print_report+0xce/0x670
kasan_report+0xd7/0x110
mlxsw_sp_sb_occ_snapshot+0xb6d/0xbc0
mlxsw_devlink_sb_occ_snapshot+0x75/0xb0
devlink_nl_sb_occ_snapshot_doit+0x1f9/0x2a0
genl_family_rcv_msg_doit+0x20c/0x300
genl_rcv_msg+0x567/0x800
netlink_rcv_skb+0x170/0x450
genl_rcv+0x2d/0x40
netlink_unicast+0x547/0x830
netlink_sendmsg+0x8d4/0xdb0
__sys_sendto+0x49b/0x510
__x64_sys_sendto+0xe5/0x1c0
do_syscall_64+0xc1/0x1d0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
[...]
Allocated by task 1:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
__kasan_kmalloc+0x8f/0xa0
copy_verifier_state+0xbc2/0xfb0
do_check_common+0x2c51/0xc7e0
bpf_check+0x5107/0x9960
bpf_prog_load+0xf0e/0x2690
__sys_bpf+0x1a61/0x49d0
__x64_sys_bpf+0x7d/0xc0
do_syscall_64+0xc1/0x1d0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 1:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3b/0x60
poison_slab_object+0x109/0x170
__kasan_slab_free+0x14/0x30
kfree+0xca/0x2b0
free_verifier_state+0xce/0x270
do_check_common+0x4828/0xc7e0
bpf_check+0x5107/0x9960
bpf_prog_load+0xf0e/0x2690
__sys_bpf+0x1a61/0x49d0
__x64_sys_bpf+0x7d/0xc0
do_syscall_64+0xc1/0x1d0
entry_SYSCALL_64_after_hwframe+0x77/0x7f |
| In the Linux kernel, the following vulnerability has been resolved:
drm/i915/gt: Fix potential UAF by revoke of fence registers
CI has been sporadically reporting the following issue triggered by
igt@i915_selftest@live@hangcheck on ADL-P and similar machines:
<6> [414.049203] i915: Running intel_hangcheck_live_selftests/igt_reset_evict_fence
...
<6> [414.068804] i915 0000:00:02.0: [drm] GT0: GUC: submission enabled
<6> [414.068812] i915 0000:00:02.0: [drm] GT0: GUC: SLPC enabled
<3> [414.070354] Unable to pin Y-tiled fence; err:-4
<3> [414.071282] i915_vma_revoke_fence:301 GEM_BUG_ON(!i915_active_is_idle(&fence->active))
...
<4>[ 609.603992] ------------[ cut here ]------------
<2>[ 609.603995] kernel BUG at drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c:301!
<4>[ 609.604003] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
<4>[ 609.604006] CPU: 0 PID: 268 Comm: kworker/u64:3 Tainted: G U W 6.9.0-CI_DRM_14785-g1ba62f8cea9c+ #1
<4>[ 609.604008] Hardware name: Intel Corporation Alder Lake Client Platform/AlderLake-P DDR4 RVP, BIOS RPLPFWI1.R00.4035.A00.2301200723 01/20/2023
<4>[ 609.604010] Workqueue: i915 __i915_gem_free_work [i915]
<4>[ 609.604149] RIP: 0010:i915_vma_revoke_fence+0x187/0x1f0 [i915]
...
<4>[ 609.604271] Call Trace:
<4>[ 609.604273] <TASK>
...
<4>[ 609.604716] __i915_vma_evict+0x2e9/0x550 [i915]
<4>[ 609.604852] __i915_vma_unbind+0x7c/0x160 [i915]
<4>[ 609.604977] force_unbind+0x24/0xa0 [i915]
<4>[ 609.605098] i915_vma_destroy+0x2f/0xa0 [i915]
<4>[ 609.605210] __i915_gem_object_pages_fini+0x51/0x2f0 [i915]
<4>[ 609.605330] __i915_gem_free_objects.isra.0+0x6a/0xc0 [i915]
<4>[ 609.605440] process_scheduled_works+0x351/0x690
...
In the past, there were similar failures reported by CI from other IGT
tests, observed on other platforms.
Before commit 63baf4f3d587 ("drm/i915/gt: Only wait for GPU activity
before unbinding a GGTT fence"), i915_vma_revoke_fence() was waiting for
idleness of vma->active via fence_update(). That commit introduced
vma->fence->active in order for the fence_update() to be able to wait
selectively on that one instead of vma->active since only idleness of
fence registers was needed. But then, another commit 0d86ee35097a
("drm/i915/gt: Make fence revocation unequivocal") replaced the call to
fence_update() in i915_vma_revoke_fence() with only fence_write(), and
also added that GEM_BUG_ON(!i915_active_is_idle(&fence->active)) in front.
No justification was provided on why we might then expect idleness of
vma->fence->active without first waiting on it.
The issue can be potentially caused by a race among revocation of fence
registers on one side and sequential execution of signal callbacks invoked
on completion of a request that was using them on the other, still
processed in parallel to revocation of those fence registers. Fix it by
waiting for idleness of vma->fence->active in i915_vma_revoke_fence().
(cherry picked from commit 24bb052d3dd499c5956abad5f7d8e4fd07da7fb1) |
| In the Linux kernel, the following vulnerability has been resolved:
cachefiles: Set object to close if ondemand_id < 0 in copen
If copen is maliciously called in the user mode, it may delete the request
corresponding to the random id. And the request may have not been read yet.
Note that when the object is set to reopen, the open request will be done
with the still reopen state in above case. As a result, the request
corresponding to this object is always skipped in select_req function, so
the read request is never completed and blocks other process.
Fix this issue by simply set object to close if its id < 0 in copen. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: PPC: Book3S HV: Prevent UAF in kvm_spapr_tce_attach_iommu_group()
Al reported a possible use-after-free (UAF) in kvm_spapr_tce_attach_iommu_group().
It looks up `stt` from tablefd, but then continues to use it after doing
fdput() on the returned fd. After the fdput() the tablefd is free to be
closed by another thread. The close calls kvm_spapr_tce_release() and
then release_spapr_tce_table() (via call_rcu()) which frees `stt`.
Although there are calls to rcu_read_lock() in
kvm_spapr_tce_attach_iommu_group() they are not sufficient to prevent
the UAF, because `stt` is used outside the locked regions.
With an artifcial delay after the fdput() and a userspace program which
triggers the race, KASAN detects the UAF:
BUG: KASAN: slab-use-after-free in kvm_spapr_tce_attach_iommu_group+0x298/0x720 [kvm]
Read of size 4 at addr c000200027552c30 by task kvm-vfio/2505
CPU: 54 PID: 2505 Comm: kvm-vfio Not tainted 6.10.0-rc3-next-20240612-dirty #1
Hardware name: 8335-GTH POWER9 0x4e1202 opal:skiboot-v6.5.3-35-g1851b2a06 PowerNV
Call Trace:
dump_stack_lvl+0xb4/0x108 (unreliable)
print_report+0x2b4/0x6ec
kasan_report+0x118/0x2b0
__asan_load4+0xb8/0xd0
kvm_spapr_tce_attach_iommu_group+0x298/0x720 [kvm]
kvm_vfio_set_attr+0x524/0xac0 [kvm]
kvm_device_ioctl+0x144/0x240 [kvm]
sys_ioctl+0x62c/0x1810
system_call_exception+0x190/0x440
system_call_vectored_common+0x15c/0x2ec
...
Freed by task 0:
...
kfree+0xec/0x3e0
release_spapr_tce_table+0xd4/0x11c [kvm]
rcu_core+0x568/0x16a0
handle_softirqs+0x23c/0x920
do_softirq_own_stack+0x6c/0x90
do_softirq_own_stack+0x58/0x90
__irq_exit_rcu+0x218/0x2d0
irq_exit+0x30/0x80
arch_local_irq_restore+0x128/0x230
arch_local_irq_enable+0x1c/0x30
cpuidle_enter_state+0x134/0x5cc
cpuidle_enter+0x6c/0xb0
call_cpuidle+0x7c/0x100
do_idle+0x394/0x410
cpu_startup_entry+0x60/0x70
start_secondary+0x3fc/0x410
start_secondary_prolog+0x10/0x14
Fix it by delaying the fdput() until `stt` is no longer in use, which
is effectively the entire function. To keep the patch minimal add a call
to fdput() at each of the existing return paths. Future work can convert
the function to goto or __cleanup style cleanup.
With the fix in place the test case no longer triggers the UAF. |
| In the Linux kernel, the following vulnerability has been resolved:
cachefiles: fix slab-use-after-free in fscache_withdraw_volume()
We got the following issue in our fault injection stress test:
==================================================================
BUG: KASAN: slab-use-after-free in fscache_withdraw_volume+0x2e1/0x370
Read of size 4 at addr ffff88810680be08 by task ondemand-04-dae/5798
CPU: 0 PID: 5798 Comm: ondemand-04-dae Not tainted 6.8.0-dirty #565
Call Trace:
kasan_check_range+0xf6/0x1b0
fscache_withdraw_volume+0x2e1/0x370
cachefiles_withdraw_volume+0x31/0x50
cachefiles_withdraw_cache+0x3ad/0x900
cachefiles_put_unbind_pincount+0x1f6/0x250
cachefiles_daemon_release+0x13b/0x290
__fput+0x204/0xa00
task_work_run+0x139/0x230
Allocated by task 5820:
__kmalloc+0x1df/0x4b0
fscache_alloc_volume+0x70/0x600
__fscache_acquire_volume+0x1c/0x610
erofs_fscache_register_volume+0x96/0x1a0
erofs_fscache_register_fs+0x49a/0x690
erofs_fc_fill_super+0x6c0/0xcc0
vfs_get_super+0xa9/0x140
vfs_get_tree+0x8e/0x300
do_new_mount+0x28c/0x580
[...]
Freed by task 5820:
kfree+0xf1/0x2c0
fscache_put_volume.part.0+0x5cb/0x9e0
erofs_fscache_unregister_fs+0x157/0x1b0
erofs_kill_sb+0xd9/0x1c0
deactivate_locked_super+0xa3/0x100
vfs_get_super+0x105/0x140
vfs_get_tree+0x8e/0x300
do_new_mount+0x28c/0x580
[...]
==================================================================
Following is the process that triggers the issue:
mount failed | daemon exit
------------------------------------------------------------
deactivate_locked_super cachefiles_daemon_release
erofs_kill_sb
erofs_fscache_unregister_fs
fscache_relinquish_volume
__fscache_relinquish_volume
fscache_put_volume(fscache_volume, fscache_volume_put_relinquish)
zero = __refcount_dec_and_test(&fscache_volume->ref, &ref);
cachefiles_put_unbind_pincount
cachefiles_daemon_unbind
cachefiles_withdraw_cache
cachefiles_withdraw_volumes
list_del_init(&volume->cache_link)
fscache_free_volume(fscache_volume)
cache->ops->free_volume
cachefiles_free_volume
list_del_init(&cachefiles_volume->cache_link);
kfree(fscache_volume)
cachefiles_withdraw_volume
fscache_withdraw_volume
fscache_volume->n_accesses
// fscache_volume UAF !!!
The fscache_volume in cache->volumes must not have been freed yet, but its
reference count may be 0. So use the new fscache_try_get_volume() helper
function try to get its reference count.
If the reference count of fscache_volume is 0, fscache_put_volume() is
freeing it, so wait for it to be removed from cache->volumes.
If its reference count is not 0, call cachefiles_withdraw_volume() with
reference count protection to avoid the above issue. |
| In the Linux kernel, the following vulnerability has been resolved:
cachefiles: fix slab-use-after-free in cachefiles_withdraw_cookie()
We got the following issue in our fault injection stress test:
==================================================================
BUG: KASAN: slab-use-after-free in cachefiles_withdraw_cookie+0x4d9/0x600
Read of size 8 at addr ffff888118efc000 by task kworker/u78:0/109
CPU: 13 PID: 109 Comm: kworker/u78:0 Not tainted 6.8.0-dirty #566
Call Trace:
<TASK>
kasan_report+0x93/0xc0
cachefiles_withdraw_cookie+0x4d9/0x600
fscache_cookie_state_machine+0x5c8/0x1230
fscache_cookie_worker+0x91/0x1c0
process_one_work+0x7fa/0x1800
[...]
Allocated by task 117:
kmalloc_trace+0x1b3/0x3c0
cachefiles_acquire_volume+0xf3/0x9c0
fscache_create_volume_work+0x97/0x150
process_one_work+0x7fa/0x1800
[...]
Freed by task 120301:
kfree+0xf1/0x2c0
cachefiles_withdraw_cache+0x3fa/0x920
cachefiles_put_unbind_pincount+0x1f6/0x250
cachefiles_daemon_release+0x13b/0x290
__fput+0x204/0xa00
task_work_run+0x139/0x230
do_exit+0x87a/0x29b0
[...]
==================================================================
Following is the process that triggers the issue:
p1 | p2
------------------------------------------------------------
fscache_begin_lookup
fscache_begin_volume_access
fscache_cache_is_live(fscache_cache)
cachefiles_daemon_release
cachefiles_put_unbind_pincount
cachefiles_daemon_unbind
cachefiles_withdraw_cache
fscache_withdraw_cache
fscache_set_cache_state(cache, FSCACHE_CACHE_IS_WITHDRAWN);
cachefiles_withdraw_objects(cache)
fscache_wait_for_objects(fscache)
atomic_read(&fscache_cache->object_count) == 0
fscache_perform_lookup
cachefiles_lookup_cookie
cachefiles_alloc_object
refcount_set(&object->ref, 1);
object->volume = volume
fscache_count_object(vcookie->cache);
atomic_inc(&fscache_cache->object_count)
cachefiles_withdraw_volumes
cachefiles_withdraw_volume
fscache_withdraw_volume
__cachefiles_free_volume
kfree(cachefiles_volume)
fscache_cookie_state_machine
cachefiles_withdraw_cookie
cache = object->volume->cache;
// cachefiles_volume UAF !!!
After setting FSCACHE_CACHE_IS_WITHDRAWN, wait for all the cookie lookups
to complete first, and then wait for fscache_cache->object_count == 0 to
avoid the cookie exiting after the volume has been freed and triggering
the above issue. Therefore call fscache_withdraw_volume() before calling
cachefiles_withdraw_objects().
This way, after setting FSCACHE_CACHE_IS_WITHDRAWN, only the following two
cases will occur:
1) fscache_begin_lookup fails in fscache_begin_volume_access().
2) fscache_withdraw_volume() will ensure that fscache_count_object() has
been executed before calling fscache_wait_for_objects(). |
| In the Linux kernel, the following vulnerability has been resolved:
cachefiles: wait for ondemand_object_worker to finish when dropping object
When queuing ondemand_object_worker() to re-open the object,
cachefiles_object is not pinned. The cachefiles_object may be freed when
the pending read request is completed intentionally and the related
erofs is umounted. If ondemand_object_worker() runs after the object is
freed, it will incur use-after-free problem as shown below.
process A processs B process C process D
cachefiles_ondemand_send_req()
// send a read req X
// wait for its completion
// close ondemand fd
cachefiles_ondemand_fd_release()
// set object as CLOSE
cachefiles_ondemand_daemon_read()
// set object as REOPENING
queue_work(fscache_wq, &info->ondemand_work)
// close /dev/cachefiles
cachefiles_daemon_release
cachefiles_flush_reqs
complete(&req->done)
// read req X is completed
// umount the erofs fs
cachefiles_put_object()
// object will be freed
cachefiles_ondemand_deinit_obj_info()
kmem_cache_free(object)
// both info and object are freed
ondemand_object_worker()
When dropping an object, it is no longer necessary to reopen the object,
so use cancel_work_sync() to cancel or wait for ondemand_object_worker()
to finish. |
| In the Linux kernel, the following vulnerability has been resolved:
cachefiles: cyclic allocation of msg_id to avoid reuse
Reusing the msg_id after a maliciously completed reopen request may cause
a read request to remain unprocessed and result in a hung, as shown below:
t1 | t2 | t3
-------------------------------------------------
cachefiles_ondemand_select_req
cachefiles_ondemand_object_is_close(A)
cachefiles_ondemand_set_object_reopening(A)
queue_work(fscache_object_wq, &info->work)
ondemand_object_worker
cachefiles_ondemand_init_object(A)
cachefiles_ondemand_send_req(OPEN)
// get msg_id 6
wait_for_completion(&req_A->done)
cachefiles_ondemand_daemon_read
// read msg_id 6 req_A
cachefiles_ondemand_get_fd
copy_to_user
// Malicious completion msg_id 6
copen 6,-1
cachefiles_ondemand_copen
complete(&req_A->done)
// will not set the object to close
// because ondemand_id && fd is valid.
// ondemand_object_worker() is done
// but the object is still reopening.
// new open req_B
cachefiles_ondemand_init_object(B)
cachefiles_ondemand_send_req(OPEN)
// reuse msg_id 6
process_open_req
copen 6,A.size
// The expected failed copen was executed successfully
Expect copen to fail, and when it does, it closes fd, which sets the
object to close, and then close triggers reopen again. However, due to
msg_id reuse resulting in a successful copen, the anonymous fd is not
closed until the daemon exits. Therefore read requests waiting for reopen
to complete may trigger hung task.
To avoid this issue, allocate the msg_id cyclically to avoid reusing the
msg_id for a very short duration of time. |
| In the Linux kernel, the following vulnerability has been resolved:
filelock: fix potential use-after-free in posix_lock_inode
Light Hsieh reported a KASAN UAF warning in trace_posix_lock_inode().
The request pointer had been changed earlier to point to a lock entry
that was added to the inode's list. However, before the tracepoint could
fire, another task raced in and freed that lock.
Fix this by moving the tracepoint inside the spinlock, which should
ensure that this doesn't happen. |
