In the Linux kernel, the following vulnerability has been resolved:
btrfs: don't check PageError in __extent_writepage
__extent_writepage currenly sets PageError whenever any error happens,
and the also checks for PageError to decide if to call error handling.
This leads to very unclear responsibility for cleaning up on errors.
In the VM and generic writeback helpers the basic idea is that once
I/O is fired off all error handling responsibility is delegated to the
end I/O handler. But if that end I/O handler sets the PageError bit,
and the submitter checks it, the bit could in some cases leak into the
submission context for fast enough I/O.
Fix this by simply not checking PageError and just using the local
ret variable to check for submission errors. This also fundamentally
solves the long problem documented in a comment in __extent_writepage
by never leaking the error bit into the submission context.
In the Linux kernel, the following vulnerability has been resolved:
drm/panfrost: Fix GEM handle creation ref-counting
panfrost_gem_create_with_handle() previously returned a BO but with the
only reference being from the handle, which user space could in theory
guess and release, causing a use-after-free. Additionally if the call to
panfrost_gem_mapping_get() in panfrost_ioctl_create_bo() failed then
a(nother) reference on the BO was dropped.
The _create_with_handle() is a problematic pattern, so ditch it and
instead create the handle in panfrost_ioctl_create_bo(). If the call to
panfrost_gem_mapping_get() fails then this means that user space has
indeed gone behind our back and freed the handle. In which case just
return an error code.
In the Linux kernel, the following vulnerability has been resolved:
rcu: Protect rcu_print_task_exp_stall() ->exp_tasks access
For kernels built with CONFIG_PREEMPT_RCU=y, the following scenario can
result in a NULL-pointer dereference:
CPU1 CPU2
rcu_preempt_deferred_qs_irqrestore rcu_print_task_exp_stall
if (special.b.blocked) READ_ONCE(rnp->exp_tasks) != NULL
raw_spin_lock_rcu_node
np = rcu_next_node_entry(t, rnp)
if (&t->rcu_node_entry == rnp->exp_tasks)
WRITE_ONCE(rnp->exp_tasks, np)
....
raw_spin_unlock_irqrestore_rcu_node
raw_spin_lock_irqsave_rcu_node
t = list_entry(rnp->exp_tasks->prev,
struct task_struct, rcu_node_entry)
(if rnp->exp_tasks is NULL, this
will dereference a NULL pointer)
The problem is that CPU2 accesses the rcu_node structure's->exp_tasks
field without holding the rcu_node structure's ->lock and CPU2 did
not observe CPU1's change to rcu_node structure's ->exp_tasks in time.
Therefore, if CPU1 sets rcu_node structure's->exp_tasks pointer to NULL,
then CPU2 might dereference that NULL pointer.
This commit therefore holds the rcu_node structure's ->lock while
accessing that structure's->exp_tasks field.
[ paulmck: Apply Frederic Weisbecker feedback. ]
In the Linux kernel, the following vulnerability has been resolved:
ntfs: Fix panic about slab-out-of-bounds caused by ntfs_listxattr()
Here is a BUG report from syzbot:
BUG: KASAN: slab-out-of-bounds in ntfs_list_ea fs/ntfs3/xattr.c:191 [inline]
BUG: KASAN: slab-out-of-bounds in ntfs_listxattr+0x401/0x570 fs/ntfs3/xattr.c:710
Read of size 1 at addr ffff888021acaf3d by task syz-executor128/3632
Call Trace:
ntfs_list_ea fs/ntfs3/xattr.c:191 [inline]
ntfs_listxattr+0x401/0x570 fs/ntfs3/xattr.c:710
vfs_listxattr fs/xattr.c:457 [inline]
listxattr+0x293/0x2d0 fs/xattr.c:804
Fix the logic of ea_all iteration. When the ea->name_len is 0,
return immediately, or Add2Ptr() would visit invalid memory
in the next loop.
[almaz.alexandrovich@paragon-software.com: lines of the patch have changed]
In the Linux kernel, the following vulnerability has been resolved:
blk-cgroup: Reinit blkg_iostat_set after clearing in blkcg_reset_stats()
When blkg_alloc() is called to allocate a blkcg_gq structure
with the associated blkg_iostat_set's, there are 2 fields within
blkg_iostat_set that requires proper initialization - blkg & sync.
The former field was introduced by commit 3b8cc6298724 ("blk-cgroup:
Optimize blkcg_rstat_flush()") while the later one was introduced by
commit f73316482977 ("blk-cgroup: reimplement basic IO stats using
cgroup rstat").
Unfortunately those fields in the blkg_iostat_set's are not properly
re-initialized when they are cleared in v1's blkcg_reset_stats(). This
can lead to a kernel panic due to NULL pointer access of the blkg
pointer. The missing initialization of sync is less problematic and
can be a problem in a debug kernel due to missing lockdep initialization.
Fix these problems by re-initializing them after memory clearing.
In the Linux kernel, the following vulnerability has been resolved:
ACPICA: Fix error code path in acpi_ds_call_control_method()
A use-after-free in acpi_ps_parse_aml() after a failing invocaion of
acpi_ds_call_control_method() is reported by KASAN [1] and code
inspection reveals that next_walk_state pushed to the thread by
acpi_ds_create_walk_state() is freed on errors, but it is not popped
from the thread beforehand. Thus acpi_ds_get_current_walk_state()
called by acpi_ps_parse_aml() subsequently returns it as the new
walk state which is incorrect.
To address this, make acpi_ds_call_control_method() call
acpi_ds_pop_walk_state() to pop next_walk_state from the thread before
returning an error.
In the Linux kernel, the following vulnerability has been resolved:
scsi: fcoe: Fix transport not deattached when fcoe_if_init() fails
fcoe_init() calls fcoe_transport_attach(&fcoe_sw_transport), but when
fcoe_if_init() fails, &fcoe_sw_transport is not detached and leaves freed
&fcoe_sw_transport on fcoe_transports list. This causes panic when
reinserting module.
BUG: unable to handle page fault for address: fffffbfff82e2213
RIP: 0010:fcoe_transport_attach+0xe1/0x230 [libfcoe]
Call Trace:
<TASK>
do_one_initcall+0xd0/0x4e0
load_module+0x5eee/0x7210
...
In the Linux kernel, the following vulnerability has been resolved:
parisc: led: Fix potential null-ptr-deref in start_task()
start_task() calls create_singlethread_workqueue() and not checked the
ret value, which may return NULL. And a null-ptr-deref may happen:
start_task()
create_singlethread_workqueue() # failed, led_wq is NULL
queue_delayed_work()
queue_delayed_work_on()
__queue_delayed_work() # warning here, but continue
__queue_work() # access wq->flags, null-ptr-deref
Check the ret value and return -ENOMEM if it is NULL.
In the Linux kernel, the following vulnerability has been resolved:
irqchip/wpcm450: Fix memory leak in wpcm450_aic_of_init()
If of_iomap() failed, 'aic' should be freed before return. Otherwise
there is a memory leak.
In the Linux kernel, the following vulnerability has been resolved:
drivers/md/md-bitmap: check the return value of md_bitmap_get_counter()
Check the return value of md_bitmap_get_counter() in case it returns
NULL pointer, which will result in a null pointer dereference.
v2: update the check to include other dereference