In the Linux kernel, the following vulnerability has been resolved:
capabilities: fix undefined behavior in bit shift for CAP_TO_MASK
Shifting signed 32-bit value by 31 bits is undefined, so changing
significant bit to unsigned. The UBSAN warning calltrace like below:
UBSAN: shift-out-of-bounds in security/commoncap.c:1252:2
left shift of 1 by 31 places cannot be represented in type 'int'
Call Trace:
<TASK>
dump_stack_lvl+0x7d/0xa5
dump_stack+0x15/0x1b
ubsan_epilogue+0xe/0x4e
__ubsan_handle_shift_out_of_bounds+0x1e7/0x20c
cap_task_prctl+0x561/0x6f0
security_task_prctl+0x5a/0xb0
__x64_sys_prctl+0x61/0x8f0
do_syscall_64+0x58/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
</TASK>
In the Linux kernel, the following vulnerability has been resolved:
scsi: scsi_transport_sas: Fix error handling in sas_phy_add()
If transport_add_device() fails in sas_phy_add(), the kernel will crash
trying to delete the device in transport_remove_device() called from
sas_remove_host().
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000108
CPU: 61 PID: 42829 Comm: rmmod Kdump: loaded Tainted: G W 6.1.0-rc1+ #173
pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : device_del+0x54/0x3d0
lr : device_del+0x37c/0x3d0
Call trace:
device_del+0x54/0x3d0
attribute_container_class_device_del+0x28/0x38
transport_remove_classdev+0x6c/0x80
attribute_container_device_trigger+0x108/0x110
transport_remove_device+0x28/0x38
sas_phy_delete+0x30/0x60 [scsi_transport_sas]
do_sas_phy_delete+0x6c/0x80 [scsi_transport_sas]
device_for_each_child+0x68/0xb0
sas_remove_children+0x40/0x50 [scsi_transport_sas]
sas_remove_host+0x20/0x38 [scsi_transport_sas]
hisi_sas_remove+0x40/0x68 [hisi_sas_main]
hisi_sas_v2_remove+0x20/0x30 [hisi_sas_v2_hw]
platform_remove+0x2c/0x60
Fix this by checking and handling return value of transport_add_device()
in sas_phy_add().
In the Linux kernel, the following vulnerability has been resolved:
hugetlbfs: don't delete error page from pagecache
This change is very similar to the change that was made for shmem [1], and
it solves the same problem but for HugeTLBFS instead.
Currently, when poison is found in a HugeTLB page, the page is removed
from the page cache. That means that attempting to map or read that
hugepage in the future will result in a new hugepage being allocated
instead of notifying the user that the page was poisoned. As [1] states,
this is effectively memory corruption.
The fix is to leave the page in the page cache. If the user attempts to
use a poisoned HugeTLB page with a syscall, the syscall will fail with
EIO, the same error code that shmem uses. For attempts to map the page,
the thread will get a BUS_MCEERR_AR SIGBUS.
[1]: commit a76054266661 ("mm: shmem: don't truncate page if memory failure happens")
In the Linux kernel, the following vulnerability has been resolved:
btrfs: zoned: initialize device's zone info for seeding
When performing seeding on a zoned filesystem it is necessary to
initialize each zoned device's btrfs_zoned_device_info structure,
otherwise mounting the filesystem will cause a NULL pointer dereference.
This was uncovered by fstests' testcase btrfs/163.
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: fix use-after-free bug of ns_writer on remount
If a nilfs2 filesystem is downgraded to read-only due to metadata
corruption on disk and is remounted read/write, or if emergency read-only
remount is performed, detaching a log writer and synchronizing the
filesystem can be done at the same time.
In these cases, use-after-free of the log writer (hereinafter
nilfs->ns_writer) can happen as shown in the scenario below:
Task1 Task2
-------------------------------- ------------------------------
nilfs_construct_segment
nilfs_segctor_sync
init_wait
init_waitqueue_entry
add_wait_queue
schedule
nilfs_remount (R/W remount case)
nilfs_attach_log_writer
nilfs_detach_log_writer
nilfs_segctor_destroy
kfree
finish_wait
_raw_spin_lock_irqsave
__raw_spin_lock_irqsave
do_raw_spin_lock
debug_spin_lock_before <-- use-after-free
While Task1 is sleeping, nilfs->ns_writer is freed by Task2. After Task1
waked up, Task1 accesses nilfs->ns_writer which is already freed. This
scenario diagram is based on the Shigeru Yoshida's post [1].
This patch fixes the issue by not detaching nilfs->ns_writer on remount so
that this UAF race doesn't happen. Along with this change, this patch
also inserts a few necessary read-only checks with superblock instance
where only the ns_writer pointer was used to check if the filesystem is
read-only.
In the Linux kernel, the following vulnerability has been resolved:
ALSA: hda: fix potential memleak in 'add_widget_node'
As 'kobject_add' may allocated memory for 'kobject->name' when return error.
And in this function, if call 'kobject_add' failed didn't free kobject.
So call 'kobject_put' to recycling resources.
In the Linux kernel, the following vulnerability has been resolved:
mISDN: fix possible memory leak in mISDN_dsp_element_register()
Afer commit 1fa5ae857bb1 ("driver core: get rid of struct device's
bus_id string array"), the name of device is allocated dynamically,
use put_device() to give up the reference, so that the name can be
freed in kobject_cleanup() when the refcount is 0.
The 'entry' is going to be freed in mISDN_dsp_dev_release(), so the
kfree() is removed. list_del() is called in mISDN_dsp_dev_release(),
so it need be initialized.
In the Linux kernel, the following vulnerability has been resolved:
dm ioctl: fix misbehavior if list_versions races with module loading
__list_versions will first estimate the required space using the
"dm_target_iterate(list_version_get_needed, &needed)" call and then will
fill the space using the "dm_target_iterate(list_version_get_info,
&iter_info)" call. Each of these calls locks the targets using the
"down_read(&_lock)" and "up_read(&_lock)" calls, however between the first
and second "dm_target_iterate" there is no lock held and the target
modules can be loaded at this point, so the second "dm_target_iterate"
call may need more space than what was the first "dm_target_iterate"
returned.
The code tries to handle this overflow (see the beginning of
list_version_get_info), however this handling is incorrect.
The code sets "param->data_size = param->data_start + needed" and
"iter_info.end = (char *)vers+len" - "needed" is the size returned by the
first dm_target_iterate call; "len" is the size of the buffer allocated by
userspace.
"len" may be greater than "needed"; in this case, the code will write up
to "len" bytes into the buffer, however param->data_size is set to
"needed", so it may write data past the param->data_size value. The ioctl
interface copies only up to param->data_size into userspace, thus part of
the result will be truncated.
Fix this bug by setting "iter_info.end = (char *)vers + needed;" - this
guarantees that the second "dm_target_iterate" call will write only up to
the "needed" buffer and it will exit with "DM_BUFFER_FULL_FLAG" if it
overflows the "needed" space - in this case, userspace will allocate a
larger buffer and retry.
Note that there is also a bug in list_version_get_needed - we need to add
"strlen(tt->name) + 1" to the needed size, not "strlen(tt->name)".
In the Linux kernel, the following vulnerability has been resolved:
ALSA: usb-audio: Drop snd_BUG_ON() from snd_usbmidi_output_open()
snd_usbmidi_output_open() has a check of the NULL port with
snd_BUG_ON(). snd_BUG_ON() was used as this shouldn't have happened,
but in reality, the NULL port may be seen when the device gives an
invalid endpoint setup at the descriptor, hence the driver skips the
allocation. That is, the check itself is valid and snd_BUG_ON()
should be dropped from there. Otherwise it's confusing as if it were
a real bug, as recently syzbot stumbled on it.