In the Linux kernel, the following vulnerability has been resolved:
bpf: Prevent tail call between progs attached to different hooks
bpf progs can be attached to kernel functions, and the attached functions
can take different parameters or return different return values. If
prog attached to one kernel function tail calls prog attached to another
kernel function, the ctx access or return value verification could be
bypassed.
For example, if prog1 is attached to func1 which takes only 1 parameter
and prog2 is attached to func2 which takes two parameters. Since verifier
assumes the bpf ctx passed to prog2 is constructed based on func2's
prototype, verifier allows prog2 to access the second parameter from
the bpf ctx passed to it. The problem is that verifier does not prevent
prog1 from passing its bpf ctx to prog2 via tail call. In this case,
the bpf ctx passed to prog2 is constructed from func1 instead of func2,
that is, the assumption for ctx access verification is bypassed.
Another example, if BPF LSM prog1 is attached to hook file_alloc_security,
and BPF LSM prog2 is attached to hook bpf_lsm_audit_rule_known. Verifier
knows the return value rules for these two hooks, e.g. it is legal for
bpf_lsm_audit_rule_known to return positive number 1, and it is illegal
for file_alloc_security to return positive number. So verifier allows
prog2 to return positive number 1, but does not allow prog1 to return
positive number. The problem is that verifier does not prevent prog1
from calling prog2 via tail call. In this case, prog2's return value 1
will be used as the return value for prog1's hook file_alloc_security.
That is, the return value rule is bypassed.
This patch adds restriction for tail call to prevent such bypasses.
In the Linux kernel, the following vulnerability has been resolved:
driver core: bus: Fix double free in driver API bus_register()
For bus_register(), any error which happens after kset_register() will
cause that @priv are freed twice, fixed by setting @priv with NULL after
the first free.
In the Linux kernel, the following vulnerability has been resolved:
ALSA: asihpi: Fix potential OOB array access
ASIHPI driver stores some values in the static array upon a response
from the driver, and its index depends on the firmware. We shouldn't
trust it blindly.
This patch adds a sanity check of the array index to fit in the array
size.
In the Linux kernel, the following vulnerability has been resolved:
platform/x86: x86-android-tablets: Fix use after free on platform_device_register() errors
x86_android_tablet_remove() frees the pdevs[] array, so it should not
be used after calling x86_android_tablet_remove().
When platform_device_register() fails, store the pdevs[x] PTR_ERR() value
into the local ret variable before calling x86_android_tablet_remove()
to avoid using pdevs[] after it has been freed.
In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: amdkfd_free_gtt_mem clear the correct pointer
Pass pointer reference to amdgpu_bo_unref to clear the correct pointer,
otherwise amdgpu_bo_unref clear the local variable, the original pointer
not set to NULL, this could cause use-after-free bug.
In the Linux kernel, the following vulnerability has been resolved:
cifs: Fix buffer overflow when parsing NFS reparse points
ReparseDataLength is sum of the InodeType size and DataBuffer size.
So to get DataBuffer size it is needed to subtract InodeType's size from
ReparseDataLength.
Function cifs_strndup_from_utf16() is currentlly accessing buf->DataBuffer
at position after the end of the buffer because it does not subtract
InodeType size from the length. Fix this problem and correctly subtract
variable len.
Member InodeType is present only when reparse buffer is large enough. Check
for ReparseDataLength before accessing InodeType to prevent another invalid
memory access.
Major and minor rdev values are present also only when reparse buffer is
large enough. Check for reparse buffer size before calling reparse_mkdev().
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix timer use-after-free on failed mount
Syzbot has found an ODEBUG bug in ext4_fill_super
The del_timer_sync function cancels the s_err_report timer,
which reminds about filesystem errors daily. We should
guarantee the timer is no longer active before kfree(sbi).
When filesystem mounting fails, the flow goes to failed_mount3,
where an error occurs when ext4_stop_mmpd is called, causing
a read I/O failure. This triggers the ext4_handle_error function
that ultimately re-arms the timer,
leaving the s_err_report timer active before kfree(sbi) is called.
Fix the issue by canceling the s_err_report timer after calling ext4_stop_mmpd.
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: cancel dqi_sync_work before freeing oinfo
ocfs2_global_read_info() will initialize and schedule dqi_sync_work at the
end, if error occurs after successfully reading global quota, it will
trigger the following warning with CONFIG_DEBUG_OBJECTS_* enabled:
ODEBUG: free active (active state 0) object: 00000000d8b0ce28 object type: timer_list hint: qsync_work_fn+0x0/0x16c
This reports that there is an active delayed work when freeing oinfo in
error handling, so cancel dqi_sync_work first. BTW, return status instead
of -1 when .read_file_info fails.