In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix netfs_read_to_pagecache() to pause on subreq failure
Fix netfs_read_to_pagecache() so that it pauses the generation of new
subrequests if an already-issued subrequest fails.
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix missing barriers when accessing stream->subrequests locklessly
The list of subrequests attached to stream->subrequests is accessed without
locks by netfs_collect_read_results() and netfs_collect_write_results(),
and then they access subreq->flags without taking a barrier after getting
the subreq pointer from the list. Relatedly, the functions that build the
list don't use any sort of write barrier when constructing the list to make
sure that the NETFS_SREQ_IN_PROGRESS flag is perceived to be set first if
no lock is taken.
Fix this by:
(1) Add a new list_add_tail_release() function that uses a release barrier
to set the pointer to the new member of the list.
(2) Add a new list_first_entry_or_null_acquire() function that uses an
acquire barrier to read the pointer to the first member in a list (or
return NULL).
(3) Use list_add_tail_release() when adding a subreq to ->subrequests.
(4) Use list_first_entry_or_null_acquire() when initially accessing the
front of the list (when an item is removed, the pointer to the new
front iterm is obtained under the same lock).
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix missing locking around retry adding new subreqs
Fix netfs_retry_read_subrequests() and netfs_retry_write_stream() to take
the appropriate lock when adding extra subrequests into
stream->subrequests.
In the Linux kernel, the following vulnerability has been resolved:
powerpc/hv-gpci: fix preempt count leak in sysfs show paths
Four sysfs show() callbacks in hv-gpci take get_cpu_var(hv_gpci_reqb)
(which calls preempt_disable()) but only call the matching put_cpu_var()
on the error path under the 'out:' label. Every successful read leaks
one preempt_disable():
processor_bus_topology_show()
processor_config_show()
affinity_domain_via_virtual_processor_show()
affinity_domain_via_domain_show()
(affinity_domain_via_partition_show() was already correct.)
On a CONFIG_PREEMPT=y kernel, repeated reads raise preempt_count and
eventually return to userspace with preemption still disabled. The
next user-mode page fault then hits faulthandler_disabled() == 1,
gets forced to SIGSEGV, and the resulting coredump trips
'BUG: scheduling while atomic' in call_usermodehelper_exec ->
wait_for_completion_state -> schedule:
BUG: scheduling while atomic: <task>/<pid>/0x00000004
...
__schedule_bug+0x6c/0x90
__schedule+0x58c/0x13a0
schedule+0x48/0x1a0
schedule_timeout+0x104/0x170
wait_for_completion_state+0x16c/0x330
call_usermodehelper_exec+0x254/0x2d0
vfs_coredump+0x1050/0x2590
get_signal+0xb9c/0xc80
do_notify_resume+0xf8/0x470
Add an out_success label that calls put_cpu_var() before returning
the byte count, mirroring affinity_domain_via_partition_show().
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix netfs_read_folio() to wait on writeback
Fix netfs_read_folio() to wait for an ongoing writeback to complete so that
it can trust the dirty flag and whatever is attached to folio->private
(folio->private may get cleaned up by the collector before it clears the
writeback flag).
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix leak of request in netfs_write_begin() error handling
Fix netfs_write_begin() to not leak our ref on the request in the event
that we get an error from netfs_wait_for_read().
In the Linux kernel, the following vulnerability has been resolved:
crypto: nx - fix nx_crypto_ctx_exit argument
nx_crypto_ctx_shash_exit calls nx_crypto_ctx_exit with crypto_shash_ctx(...)
but crypto_shash_ctx gives a nx_crypto_ctx *, not a crypto_tfm *.
Fix the type in nx_crypto_ctx_exit and drop the bogus crypto_tfm_ctx
call.
This fixes the following oops:
BUG: Unable to handle kernel data access at 0xc0403effffffffc8
Faulting instruction address: 0xc000000000396cb4
Oops: Kernel access of bad area, sig: 11 [#15]
Call Trace:
nx_crypto_ctx_shash_exit+0x24/0x60
crypto_shash_exit_tfm+0x28/0x40
crypto_destroy_tfm+0x98/0x140
crypto_exit_ahash_using_shash+0x20/0x40
crypto_destroy_tfm+0x98/0x140
hash_release+0x1c/0x30
alg_sock_destruct+0x38/0x60
__sk_destruct+0x48/0x2b0
af_alg_release+0x58/0xb0
__sock_release+0x68/0x150
sock_close+0x20/0x40
__fput+0x110/0x3a0
sys_close+0x48/0xa0
system_call_exception+0x140/0x2d0
system_call_common+0xf4/0x258
.. which came from hardlink(1) opportunistically using AF_ALG.
The same problem exists with nx_crypto_ctx_skcipher_exit getting a context
it wasn't expecting, but apparently nobody hit that for years.
In the Linux kernel, the following vulnerability has been resolved:
fbdev: omap2: fix use-after-free in omapfb_mmap
omapfb_mmap() has a race condition with OMAPFB_SETUP_PLANE ioctl that
can lead to use-after-free:
The fb_mmap() entry point holds mm_lock but not lock (fb_info->lock),
while ioctl handlers like OMAPFB_SETUP_PLANE hold lock but not mm_lock.
This allows concurrent execution.
In omapfb_mmap():
1. rg = omapfb_get_mem_region(ofbi->region); // Get old region ref
2. start = omapfb_get_region_paddr(ofbi); // Read from NEW region
3. len = fix->smem_len; // Read from NEW region
4. vm_iomap_memory(vma, start, len); // Map NEW region memory
5. atomic_inc(&rg->map_count); // Increment OLD region!
Concurrently, OMAPFB_SETUP_PLANE can:
- Reassign ofbi->region = new_rg
- Update fix->smem_len
- OMAPFB_SETUP_MEM then checks NEW region's map_count (0!) and frees it
This leaves userspace with a mapping to freed physical memory.
The fix is to read all required values (start, len) from the same
region reference (rg) that will have its map_count incremented,
preventing the region from being freed while still mapped.
In the Linux kernel, the following vulnerability has been resolved:
drm/msm: always recover the gpu
Previously, in case there was no more work to do, recover worker
wouldn't trigger recovery and would instead rely on the gpu going to
sleep and then resuming when more work is submitted.
Recover_worker will first increment the fence of the hung ring so, if
there's only one job submitted to a ring and that causes an hang, it
will early out.
There's no guarantee that the gpu will suspend and resume before more
work is submitted and if the gpu is in a hung state it will stay in that
state and probably trigger a timeout again.
Just stop checking and always recover the gpu.
Patchwork: https://patchwork.freedesktop.org/patch/704066/
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix fsck inconsistency caused by incorrect nat_entry flag usage
f2fs_need_dentry_mark() reads nat_entry flags without mutual exclusion
with the checkpoint path, which can result in an incorrect inode block
marking state. The scenario is as follows:
create & write & fsync 'file A' write checkpoint
- f2fs_do_sync_file // inline inode
- f2fs_write_inode // inode folio is dirty
- f2fs_write_checkpoint
- f2fs_flush_merged_writes
- f2fs_sync_node_pages
- f2fs_fsync_node_pages // no dirty node
- f2fs_need_inode_block_update // return true
- f2fs_fsync_node_pages // inode dirtied
- f2fs_need_dentry_mark //return true
- f2fs_flush_nat_entries
- f2fs_write_checkpoint end
- __write_node_folio // inode with DENT_BIT_SHIFT set
SPO, "fsck --dry-run" find inode has already checkpointed but still
with DENT_BIT_SHIFT set
The state observed by f2fs_need_dentry_mark() can differ from the state
observed in __write_node_folio() after acquiring sbi->node_write. The
root cause is that the semantics of IS_CHECKPOINTED and
HAS_FSYNCED_INODE are only guaranteed after the checkpoint write has
fully completed.
This patch moves set_dentry_mark() into __write_node_folio() and
protects it with the sbi->node_write lock.