Security Vulnerabilities
- CVEs Published In November 2024
In the Linux kernel, the following vulnerability has been resolved:
NFSD: Initialize struct nfsd4_copy earlier
Ensure the refcount and async_copies fields are initialized early.
cleanup_async_copy() will reference these fields if an error occurs
in nfsd4_copy(). If they are not correctly initialized, at the very
least, a refcount underflow occurs.
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: Additional check in ntfs_file_release
In the Linux kernel, the following vulnerability has been resolved:
cxl/port: Fix use-after-free, permit out-of-order decoder shutdown
In support of investigating an initialization failure report [1],
cxl_test was updated to register mock memory-devices after the mock
root-port/bus device had been registered. That led to cxl_test crashing
with a use-after-free bug with the following signature:
cxl_port_attach_region: cxl region3: cxl_host_bridge.0:port3 decoder3.0 add: mem0:decoder7.0 @ 0 next: cxl_switch_uport.0 nr_eps: 1 nr_targets: 1
cxl_port_attach_region: cxl region3: cxl_host_bridge.0:port3 decoder3.0 add: mem4:decoder14.0 @ 1 next: cxl_switch_uport.0 nr_eps: 2 nr_targets: 1
cxl_port_setup_targets: cxl region3: cxl_switch_uport.0:port6 target[0] = cxl_switch_dport.0 for mem0:decoder7.0 @ 0
1) cxl_port_setup_targets: cxl region3: cxl_switch_uport.0:port6 target[1] = cxl_switch_dport.4 for mem4:decoder14.0 @ 1
[..]
cxld_unregister: cxl decoder14.0:
cxl_region_decode_reset: cxl_region region3:
mock_decoder_reset: cxl_port port3: decoder3.0 reset
2) mock_decoder_reset: cxl_port port3: decoder3.0: out of order reset, expected decoder3.1
cxl_endpoint_decoder_release: cxl decoder14.0:
[..]
cxld_unregister: cxl decoder7.0:
3) cxl_region_decode_reset: cxl_region region3:
Oops: general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6bc3: 0000 [#1] PREEMPT SMP PTI
[..]
RIP: 0010:to_cxl_port+0x8/0x60 [cxl_core]
[..]
Call Trace:
<TASK>
cxl_region_decode_reset+0x69/0x190 [cxl_core]
cxl_region_detach+0xe8/0x210 [cxl_core]
cxl_decoder_kill_region+0x27/0x40 [cxl_core]
cxld_unregister+0x5d/0x60 [cxl_core]
At 1) a region has been established with 2 endpoint decoders (7.0 and
14.0). Those endpoints share a common switch-decoder in the topology
(3.0). At teardown, 2), decoder14.0 is the first to be removed and hits
the "out of order reset case" in the switch decoder. The effect though
is that region3 cleanup is aborted leaving it in-tact and
referencing decoder14.0. At 3) the second attempt to teardown region3
trips over the stale decoder14.0 object which has long since been
deleted.
The fix here is to recognize that the CXL specification places no
mandate on in-order shutdown of switch-decoders, the driver enforces
in-order allocation, and hardware enforces in-order commit. So, rather
than fail and leave objects dangling, always remove them.
In support of making cxl_region_decode_reset() always succeed,
cxl_region_invalidate_memregion() failures are turned into warnings.
Crashing the kernel is ok there since system integrity is at risk if
caches cannot be managed around physical address mutation events like
CXL region destruction.
A new device_for_each_child_reverse_from() is added to cleanup
port->commit_end after all dependent decoders have been disabled. In
other words if decoders are allocated 0->1->2 and disabled 1->2->0 then
port->commit_end only decrements from 2 after 2 has been disabled, and
it decrements all the way to zero since 1 was disabled previously.
In the Linux kernel, the following vulnerability has been resolved:
thunderbolt: Fix KASAN reported stack out-of-bounds read in tb_retimer_scan()
KASAN reported following issue:
BUG: KASAN: stack-out-of-bounds in tb_retimer_scan+0xffe/0x1550 [thunderbolt]
Read of size 4 at addr ffff88810111fc1c by task kworker/u56:0/11
CPU: 0 UID: 0 PID: 11 Comm: kworker/u56:0 Tainted: G U 6.11.0+ #1387
Tainted: [U]=USER
Workqueue: thunderbolt0 tb_handle_hotplug [thunderbolt]
Call Trace:
<TASK>
dump_stack_lvl+0x6c/0x90
print_report+0xd1/0x630
kasan_report+0xdb/0x110
__asan_report_load4_noabort+0x14/0x20
tb_retimer_scan+0xffe/0x1550 [thunderbolt]
tb_scan_port+0xa6f/0x2060 [thunderbolt]
tb_handle_hotplug+0x17b1/0x3080 [thunderbolt]
process_one_work+0x626/0x1100
worker_thread+0x6c8/0xfa0
kthread+0x2c8/0x3a0
ret_from_fork+0x3a/0x80
ret_from_fork_asm+0x1a/0x30
This happens because the loop variable still gets incremented by one so
max becomes 3 instead of 2, and this makes the second loop read past the
the array declared on the stack.
Fix this by assigning to max directly in the loop body.
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: fix potential deadlock with newly created symlinks
Syzbot reported that page_symlink(), called by nilfs_symlink(), triggers
memory reclamation involving the filesystem layer, which can result in
circular lock dependencies among the reader/writer semaphore
nilfs->ns_segctor_sem, s_writers percpu_rwsem (intwrite) and the
fs_reclaim pseudo lock.
This is because after commit 21fc61c73c39 ("don't put symlink bodies in
pagecache into highmem"), the gfp flags of the page cache for symbolic
links are overwritten to GFP_KERNEL via inode_nohighmem().
This is not a problem for symlinks read from the backing device, because
the __GFP_FS flag is dropped after inode_nohighmem() is called. However,
when a new symlink is created with nilfs_symlink(), the gfp flags remain
overwritten to GFP_KERNEL. Then, memory allocation called from
page_symlink() etc. triggers memory reclamation including the FS layer,
which may call nilfs_evict_inode() or nilfs_dirty_inode(). And these can
cause a deadlock if they are called while nilfs->ns_segctor_sem is held:
Fix this issue by dropping the __GFP_FS flag from the page cache GFP flags
of newly created symlinks in the same way that nilfs_new_inode() and
__nilfs_read_inode() do, as a workaround until we adopt nofs allocation
scope consistently or improve the locking constraints.
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: fix kernel bug due to missing clearing of checked flag
Syzbot reported that in directory operations after nilfs2 detects
filesystem corruption and degrades to read-only,
__block_write_begin_int(), which is called to prepare block writes, may
fail the BUG_ON check for accesses exceeding the folio/page size,
triggering a kernel bug.
This was found to be because the "checked" flag of a page/folio was not
cleared when it was discarded by nilfs2's own routine, which causes the
sanity check of directory entries to be skipped when the directory
page/folio is reloaded. So, fix that.
This was necessary when the use of nilfs2's own page discard routine was
applied to more than just metadata files.
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix use-after-free of block device file in __btrfs_free_extra_devids()
Mounting btrfs from two images (which have the same one fsid and two
different dev_uuids) in certain executing order may trigger an UAF for
variable 'device->bdev_file' in __btrfs_free_extra_devids(). And
following are the details:
1. Attach image_1 to loop0, attach image_2 to loop1, and scan btrfs
devices by ioctl(BTRFS_IOC_SCAN_DEV):
/ btrfs_device_1 → loop0
fs_device
\ btrfs_device_2 → loop1
2. mount /dev/loop0 /mnt
btrfs_open_devices
btrfs_device_1->bdev_file = btrfs_get_bdev_and_sb(loop0)
btrfs_device_2->bdev_file = btrfs_get_bdev_and_sb(loop1)
btrfs_fill_super
open_ctree
fail: btrfs_close_devices // -ENOMEM
btrfs_close_bdev(btrfs_device_1)
fput(btrfs_device_1->bdev_file)
// btrfs_device_1->bdev_file is freed
btrfs_close_bdev(btrfs_device_2)
fput(btrfs_device_2->bdev_file)
3. mount /dev/loop1 /mnt
btrfs_open_devices
btrfs_get_bdev_and_sb(&bdev_file)
// EIO, btrfs_device_1->bdev_file is not assigned,
// which points to a freed memory area
btrfs_device_2->bdev_file = btrfs_get_bdev_and_sb(loop1)
btrfs_fill_super
open_ctree
btrfs_free_extra_devids
if (btrfs_device_1->bdev_file)
fput(btrfs_device_1->bdev_file) // UAF !
Fix it by setting 'device->bdev_file' as 'NULL' after closing the
btrfs_device in btrfs_close_one_device().
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: pass u64 to ocfs2_truncate_inline maybe overflow
Syzbot reported a kernel BUG in ocfs2_truncate_inline. There are two
reasons for this: first, the parameter value passed is greater than
ocfs2_max_inline_data_with_xattr, second, the start and end parameters of
ocfs2_truncate_inline are "unsigned int".
So, we need to add a sanity check for byte_start and byte_len right before
ocfs2_truncate_inline() in ocfs2_remove_inode_range(), if they are greater
than ocfs2_max_inline_data_with_xattr return -EINVAL.
In the Linux kernel, the following vulnerability has been resolved:
fork: do not invoke uffd on fork if error occurs
Patch series "fork: do not expose incomplete mm on fork".
During fork we may place the virtual memory address space into an
inconsistent state before the fork operation is complete.
In addition, we may encounter an error during the fork operation that
indicates that the virtual memory address space is invalidated.
As a result, we should not be exposing it in any way to external machinery
that might interact with the mm or VMAs, machinery that is not designed to
deal with incomplete state.
We specifically update the fork logic to defer khugepaged and ksm to the
end of the operation and only to be invoked if no error arose, and
disallow uffd from observing fork events should an error have occurred.
This patch (of 2):
Currently on fork we expose the virtual address space of a process to
userland unconditionally if uffd is registered in VMAs, regardless of
whether an error arose in the fork.
This is performed in dup_userfaultfd_complete() which is invoked
unconditionally, and performs two duties - invoking registered handlers
for the UFFD_EVENT_FORK event via dup_fctx(), and clearing down
userfaultfd_fork_ctx objects established in dup_userfaultfd().
This is problematic, because the virtual address space may not yet be
correctly initialised if an error arose.
The change in commit d24062914837 ("fork: use __mt_dup() to duplicate
maple tree in dup_mmap()") makes this more pertinent as we may be in a
state where entries in the maple tree are not yet consistent.
We address this by, on fork error, ensuring that we roll back state that
we would otherwise expect to clean up through the event being handled by
userland and perform the memory freeing duty otherwise performed by
dup_userfaultfd_complete().
We do this by implementing a new function, dup_userfaultfd_fail(), which
performs the same loop, only decrementing reference counts.
Note that we perform mmgrab() on the parent and child mm's, however
userfaultfd_ctx_put() will mmdrop() this once the reference count drops to
zero, so we will avoid memory leaks correctly here.
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/pm: Vangogh: Fix kernel memory out of bounds write
KASAN reports that the GPU metrics table allocated in
vangogh_tables_init() is not large enough for the memset done in
smu_cmn_init_soft_gpu_metrics(). Condensed report follows:
[ 33.861314] BUG: KASAN: slab-out-of-bounds in smu_cmn_init_soft_gpu_metrics+0x73/0x200 [amdgpu]
[ 33.861799] Write of size 168 at addr ffff888129f59500 by task mangoapp/1067
...
[ 33.861808] CPU: 6 UID: 1000 PID: 1067 Comm: mangoapp Tainted: G W 6.12.0-rc4 #356 1a56f59a8b5182eeaf67eb7cb8b13594dd23b544
[ 33.861816] Tainted: [W]=WARN
[ 33.861818] Hardware name: Valve Galileo/Galileo, BIOS F7G0107 12/01/2023
[ 33.861822] Call Trace:
[ 33.861826] <TASK>
[ 33.861829] dump_stack_lvl+0x66/0x90
[ 33.861838] print_report+0xce/0x620
[ 33.861853] kasan_report+0xda/0x110
[ 33.862794] kasan_check_range+0xfd/0x1a0
[ 33.862799] __asan_memset+0x23/0x40
[ 33.862803] smu_cmn_init_soft_gpu_metrics+0x73/0x200 [amdgpu 13b1bc364ec578808f676eba412c20eaab792779]
[ 33.863306] vangogh_get_gpu_metrics_v2_4+0x123/0xad0 [amdgpu 13b1bc364ec578808f676eba412c20eaab792779]
[ 33.864257] vangogh_common_get_gpu_metrics+0xb0c/0xbc0 [amdgpu 13b1bc364ec578808f676eba412c20eaab792779]
[ 33.865682] amdgpu_dpm_get_gpu_metrics+0xcc/0x110 [amdgpu 13b1bc364ec578808f676eba412c20eaab792779]
[ 33.866160] amdgpu_get_gpu_metrics+0x154/0x2d0 [amdgpu 13b1bc364ec578808f676eba412c20eaab792779]
[ 33.867135] dev_attr_show+0x43/0xc0
[ 33.867147] sysfs_kf_seq_show+0x1f1/0x3b0
[ 33.867155] seq_read_iter+0x3f8/0x1140
[ 33.867173] vfs_read+0x76c/0xc50
[ 33.867198] ksys_read+0xfb/0x1d0
[ 33.867214] do_syscall_64+0x90/0x160
...
[ 33.867353] Allocated by task 378 on cpu 7 at 22.794876s:
[ 33.867358] kasan_save_stack+0x33/0x50
[ 33.867364] kasan_save_track+0x17/0x60
[ 33.867367] __kasan_kmalloc+0x87/0x90
[ 33.867371] vangogh_init_smc_tables+0x3f9/0x840 [amdgpu]
[ 33.867835] smu_sw_init+0xa32/0x1850 [amdgpu]
[ 33.868299] amdgpu_device_init+0x467b/0x8d90 [amdgpu]
[ 33.868733] amdgpu_driver_load_kms+0x19/0xf0 [amdgpu]
[ 33.869167] amdgpu_pci_probe+0x2d6/0xcd0 [amdgpu]
[ 33.869608] local_pci_probe+0xda/0x180
[ 33.869614] pci_device_probe+0x43f/0x6b0
Empirically we can confirm that the former allocates 152 bytes for the
table, while the latter memsets the 168 large block.
Root cause appears that when GPU metrics tables for v2_4 parts were added
it was not considered to enlarge the table to fit.
The fix in this patch is rather "brute force" and perhaps later should be
done in a smarter way, by extracting and consolidating the part version to
size logic to a common helper, instead of brute forcing the largest
possible allocation. Nevertheless, for now this works and fixes the out of
bounds write.
v2:
* Drop impossible v3_0 case. (Mario)
(cherry picked from commit 0880f58f9609f0200483a49429af0f050d281703)