In the Linux kernel, the following vulnerability has been resolved:
block, bfq: fix possible uaf for 'bfqq->bic'
Our test report a uaf for 'bfqq->bic' in 5.10:
==================================================================
BUG: KASAN: use-after-free in bfq_select_queue+0x378/0xa30
CPU: 6 PID: 2318352 Comm: fsstress Kdump: loaded Not tainted 5.10.0-60.18.0.50.h602.kasan.eulerosv2r11.x86_64 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-20220320_160524-szxrtosci10000 04/01/2014
Call Trace:
bfq_select_queue+0x378/0xa30
bfq_dispatch_request+0xe8/0x130
blk_mq_do_dispatch_sched+0x62/0xb0
__blk_mq_sched_dispatch_requests+0x215/0x2a0
blk_mq_sched_dispatch_requests+0x8f/0xd0
__blk_mq_run_hw_queue+0x98/0x180
__blk_mq_delay_run_hw_queue+0x22b/0x240
blk_mq_run_hw_queue+0xe3/0x190
blk_mq_sched_insert_requests+0x107/0x200
blk_mq_flush_plug_list+0x26e/0x3c0
blk_finish_plug+0x63/0x90
__iomap_dio_rw+0x7b5/0x910
iomap_dio_rw+0x36/0x80
ext4_dio_read_iter+0x146/0x190 [ext4]
ext4_file_read_iter+0x1e2/0x230 [ext4]
new_sync_read+0x29f/0x400
vfs_read+0x24e/0x2d0
ksys_read+0xd5/0x1b0
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x61/0xc6
Commit 3bc5e683c67d ("bfq: Split shared queues on move between cgroups")
changes that move process to a new cgroup will allocate a new bfqq to
use, however, the old bfqq and new bfqq can point to the same bic:
1) Initial state, two process with io in the same cgroup.
Process 1 Process 2
(BIC1) (BIC2)
| Λ | Λ
| | | |
V | V |
bfqq1 bfqq2
2) bfqq1 is merged to bfqq2.
Process 1 Process 2
(BIC1) (BIC2)
| |
\-------------\|
V
bfqq1 bfqq2(coop)
3) Process 1 exit, then issue new io(denoce IOA) from Process 2.
(BIC2)
| Λ
| |
V |
bfqq2(coop)
4) Before IOA is completed, move Process 2 to another cgroup and issue io.
Process 2
(BIC2)
Λ
|\--------------\
| V
bfqq2 bfqq3
Now that BIC2 points to bfqq3, while bfqq2 and bfqq3 both point to BIC2.
If all the requests are completed, and Process 2 exit, BIC2 will be
freed while there is no guarantee that bfqq2 will be freed before BIC2.
Fix the problem by clearing bfqq->bic while bfqq is detached from bic.
In the Linux kernel, the following vulnerability has been resolved:
ntb_netdev: Use dev_kfree_skb_any() in interrupt context
TX/RX callback handlers (ntb_netdev_tx_handler(),
ntb_netdev_rx_handler()) can be called in interrupt
context via the DMA framework when the respective
DMA operations have completed. As such, any calls
by these routines to free skb's, should use the
interrupt context safe dev_kfree_skb_any() function.
Previously, these callback handlers would call the
interrupt unsafe version of dev_kfree_skb(). This has
not presented an issue on Intel IOAT DMA engines as
that driver utilizes tasklets rather than a hard
interrupt handler, like the AMD PTDMA DMA driver.
On AMD systems, a kernel WARNING message is
encountered, which is being issued from
skb_release_head_state() due to in_hardirq()
being true.
Besides the user visible WARNING from the kernel,
the other symptom of this bug was that TCP/IP performance
across the ntb_netdev interface was very poor, i.e.
approximately an order of magnitude below what was
expected. With the repair to use dev_kfree_skb_any(),
kernel WARNINGs from skb_release_head_state() ceased
and TCP/IP performance, as measured by iperf, was on
par with expected results, approximately 20 Gb/s on
AMD Milan based server. Note that this performance
is comparable with Intel based servers.
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: fix shift-out-of-bounds/overflow in nilfs_sb2_bad_offset()
Patch series "nilfs2: fix UBSAN shift-out-of-bounds warnings on mount
time".
The first patch fixes a bug reported by syzbot, and the second one fixes
the remaining bug of the same kind. Although they are triggered by the
same super block data anomaly, I divided it into the above two because the
details of the issues and how to fix it are different.
Both are required to eliminate the shift-out-of-bounds issues at mount
time.
This patch (of 2):
If the block size exponent information written in an on-disk superblock is
corrupted, nilfs_sb2_bad_offset helper function can trigger
shift-out-of-bounds warning followed by a kernel panic (if panic_on_warn
is set):
shift exponent 38983 is too large for 64-bit type 'unsigned long long'
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
ubsan_epilogue lib/ubsan.c:151 [inline]
__ubsan_handle_shift_out_of_bounds+0x33d/0x3b0 lib/ubsan.c:322
nilfs_sb2_bad_offset fs/nilfs2/the_nilfs.c:449 [inline]
nilfs_load_super_block+0xdf5/0xe00 fs/nilfs2/the_nilfs.c:523
init_nilfs+0xb7/0x7d0 fs/nilfs2/the_nilfs.c:577
nilfs_fill_super+0xb1/0x5d0 fs/nilfs2/super.c:1047
nilfs_mount+0x613/0x9b0 fs/nilfs2/super.c:1317
...
In addition, since nilfs_sb2_bad_offset() performs multiplication without
considering the upper bound, the computation may overflow if the disk
layout parameters are not normal.
This fixes these issues by inserting preliminary sanity checks for those
parameters and by converting the comparison from one involving
multiplication and left bit-shifting to one using division and right
bit-shifting.
In the Linux kernel, the following vulnerability has been resolved:
drm/amd: fix potential memory leak
This patch fix potential memory leak (clk_src) when function run
into last return NULL.
s/free/kfree/ - Alex
In the Linux kernel, the following vulnerability has been resolved:
cxl: fix possible null-ptr-deref in cxl_guest_init_afu|adapter()
If device_register() fails in cxl_register_afu|adapter(), the device
is not added, device_unregister() can not be called in the error path,
otherwise it will cause a null-ptr-deref because of removing not added
device.
As comment of device_register() says, it should use put_device() to give
up the reference in the error path. So split device_unregister() into
device_del() and put_device(), then goes to put dev when register fails.
In the Linux kernel, the following vulnerability has been resolved:
iommu/vt-d: Clean up si_domain in the init_dmars() error path
A splat from kmem_cache_destroy() was seen with a kernel prior to
commit ee2653bbe89d ("iommu/vt-d: Remove domain and devinfo mempool")
when there was a failure in init_dmars(), because the iommu_domain
cache still had objects. While the mempool code is now gone, there
still is a leak of the si_domain memory if init_dmars() fails. So
clean up si_domain in the init_dmars() error path.
In the Linux kernel, the following vulnerability has been resolved:
cpufreq: Init completion before kobject_init_and_add()
In cpufreq_policy_alloc(), it will call uninitialed completion in
cpufreq_sysfs_release() when kobject_init_and_add() fails. And
that will cause a crash such as the following page fault in complete:
BUG: unable to handle page fault for address: fffffffffffffff8
[..]
RIP: 0010:complete+0x98/0x1f0
[..]
Call Trace:
kobject_put+0x1be/0x4c0
cpufreq_online.cold+0xee/0x1fd
cpufreq_add_dev+0x183/0x1e0
subsys_interface_register+0x3f5/0x4e0
cpufreq_register_driver+0x3b7/0x670
acpi_cpufreq_init+0x56c/0x1000 [acpi_cpufreq]
do_one_initcall+0x13d/0x780
do_init_module+0x1c3/0x630
load_module+0x6e67/0x73b0
__do_sys_finit_module+0x181/0x240
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd