In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to do sanity check on curseg->alloc_type
As Wenqing Liu reported in bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=215657
- Overview
UBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2 when mount and operate a corrupted image
- Reproduce
tested on kernel 5.17-rc4, 5.17-rc6
1. mkdir test_crash
2. cd test_crash
3. unzip tmp2.zip
4. mkdir mnt
5. ./single_test.sh f2fs 2
- Kernel dump
[ 46.434454] loop0: detected capacity change from 0 to 131072
[ 46.529839] F2FS-fs (loop0): Mounted with checkpoint version = 7548c2d9
[ 46.738319] ================================================================================
[ 46.738412] UBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2
[ 46.738475] index 231 is out of range for type 'unsigned int [2]'
[ 46.738539] CPU: 2 PID: 939 Comm: umount Not tainted 5.17.0-rc6 #1
[ 46.738547] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014
[ 46.738551] Call Trace:
[ 46.738556] <TASK>
[ 46.738563] dump_stack_lvl+0x47/0x5c
[ 46.738581] ubsan_epilogue+0x5/0x50
[ 46.738592] __ubsan_handle_out_of_bounds+0x68/0x80
[ 46.738604] f2fs_allocate_data_block+0xdff/0xe60 [f2fs]
[ 46.738819] do_write_page+0xef/0x210 [f2fs]
[ 46.738934] f2fs_do_write_node_page+0x3f/0x80 [f2fs]
[ 46.739038] __write_node_page+0x2b7/0x920 [f2fs]
[ 46.739162] f2fs_sync_node_pages+0x943/0xb00 [f2fs]
[ 46.739293] f2fs_write_checkpoint+0x7bb/0x1030 [f2fs]
[ 46.739405] kill_f2fs_super+0x125/0x150 [f2fs]
[ 46.739507] deactivate_locked_super+0x60/0xc0
[ 46.739517] deactivate_super+0x70/0xb0
[ 46.739524] cleanup_mnt+0x11a/0x200
[ 46.739532] __cleanup_mnt+0x16/0x20
[ 46.739538] task_work_run+0x67/0xa0
[ 46.739547] exit_to_user_mode_prepare+0x18c/0x1a0
[ 46.739559] syscall_exit_to_user_mode+0x26/0x40
[ 46.739568] do_syscall_64+0x46/0xb0
[ 46.739584] entry_SYSCALL_64_after_hwframe+0x44/0xae
The root cause is we missed to do sanity check on curseg->alloc_type,
result in out-of-bound accessing on sbi->block_count[] array, fix it.
In the Linux kernel, the following vulnerability has been resolved:
parisc: Fix non-access data TLB cache flush faults
When a page is not present, we get non-access data TLB faults from
the fdc and fic instructions in flush_user_dcache_range_asm and
flush_user_icache_range_asm. When these occur, the cache line is
not invalidated and potentially we get memory corruption. The
problem was hidden by the nullification of the flush instructions.
These faults also affect performance. With pa8800/pa8900 processors,
there will be 32 faults per 4 KB page since the cache line is 128
bytes. There will be more faults with earlier processors.
The problem is fixed by using flush_cache_pages(). It does the flush
using a tmp alias mapping.
The flush_cache_pages() call in flush_cache_range() flushed too
large a range.
V2: Remove unnecessary preempt_disable() and preempt_enable() calls.
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix ext4_mb_mark_bb() with flex_bg with fast_commit
In case of flex_bg feature (which is by default enabled), extents for
any given inode might span across blocks from two different block group.
ext4_mb_mark_bb() only reads the buffer_head of block bitmap once for the
starting block group, but it fails to read it again when the extent length
boundary overflows to another block group. Then in this below loop it
accesses memory beyond the block group bitmap buffer_head and results
into a data abort.
for (i = 0; i < clen; i++)
if (!mb_test_bit(blkoff + i, bitmap_bh->b_data) == !state)
already++;
This patch adds this functionality for checking block group boundary in
ext4_mb_mark_bb() and update the buffer_head(bitmap_bh) for every different
block group.
w/o this patch, I was easily able to hit a data access abort using Power platform.
<...>
[ 74.327662] EXT4-fs error (device loop3): ext4_mb_generate_buddy:1141: group 11, block bitmap and bg descriptor inconsistent: 21248 vs 23294 free clusters
[ 74.533214] EXT4-fs (loop3): shut down requested (2)
[ 74.536705] Aborting journal on device loop3-8.
[ 74.702705] BUG: Unable to handle kernel data access on read at 0xc00000005e980000
[ 74.703727] Faulting instruction address: 0xc0000000007bffb8
cpu 0xd: Vector: 300 (Data Access) at [c000000015db7060]
pc: c0000000007bffb8: ext4_mb_mark_bb+0x198/0x5a0
lr: c0000000007bfeec: ext4_mb_mark_bb+0xcc/0x5a0
sp: c000000015db7300
msr: 800000000280b033
dar: c00000005e980000
dsisr: 40000000
current = 0xc000000027af6880
paca = 0xc00000003ffd5200 irqmask: 0x03 irq_happened: 0x01
pid = 5167, comm = mount
<...>
enter ? for help
[c000000015db7380] c000000000782708 ext4_ext_clear_bb+0x378/0x410
[c000000015db7400] c000000000813f14 ext4_fc_replay+0x1794/0x2000
[c000000015db7580] c000000000833f7c do_one_pass+0xe9c/0x12a0
[c000000015db7710] c000000000834504 jbd2_journal_recover+0x184/0x2d0
[c000000015db77c0] c000000000841398 jbd2_journal_load+0x188/0x4a0
[c000000015db7880] c000000000804de8 ext4_fill_super+0x2638/0x3e10
[c000000015db7a40] c0000000005f8404 get_tree_bdev+0x2b4/0x350
[c000000015db7ae0] c0000000007ef058 ext4_get_tree+0x28/0x40
[c000000015db7b00] c0000000005f6344 vfs_get_tree+0x44/0x100
[c000000015db7b70] c00000000063c408 path_mount+0xdd8/0xe70
[c000000015db7c40] c00000000063c8f0 sys_mount+0x450/0x550
[c000000015db7d50] c000000000035770 system_call_exception+0x4a0/0x4e0
[c000000015db7e10] c00000000000c74c system_call_common+0xec/0x250
In the Linux kernel, the following vulnerability has been resolved:
hwrng: cavium - fix NULL but dereferenced coccicheck error
Fix following coccicheck warning:
./drivers/char/hw_random/cavium-rng-vf.c:182:17-20: ERROR:
pdev is NULL but dereferenced.
In the Linux kernel, the following vulnerability has been resolved:
memstick/mspro_block: fix handling of read-only devices
Use set_disk_ro to propagate the read-only state to the block layer
instead of checking for it in ->open and leaking a reference in case
of a read-only device.
In the Linux kernel, the following vulnerability has been resolved:
powerpc/tm: Fix more userspace r13 corruption
Commit cf13435b730a ("powerpc/tm: Fix userspace r13 corruption") fixes a
problem in treclaim where a SLB miss can occur on the
thread_struct->ckpt_regs while SCRATCH0 is live with the saved user r13
value, clobbering it with the kernel r13 and ultimately resulting in
kernel r13 being stored in ckpt_regs.
There is an equivalent problem in trechkpt where the user r13 value is
loaded into r13 from chkpt_regs to be recheckpointed, but a SLB miss
could occur on ckpt_regs accesses after that, which will result in r13
being clobbered with a kernel value and that will get recheckpointed and
then restored to user registers.
The same memory page is accessed right before this critical window where
a SLB miss could cause corruption, so hitting the bug requires the SLB
entry be removed within a small window of instructions, which is
possible if a SLB related MCE hits there. PAPR also permits the
hypervisor to discard this SLB entry (because slb_shadow->persistent is
only set to SLB_NUM_BOLTED) although it's not known whether any
implementations would do this (KVM does not). So this is an extremely
unlikely bug, only found by inspection.
Fix this by also storing user r13 in a temporary location on the kernel
stack and don't change the r13 register from kernel r13 until the RI=0
critical section that does not fault.
The SCRATCH0 change is not strictly part of the fix, it's only used in
the RI=0 section so it does not have the same problem as the previous
SCRATCH0 bug.
In the Linux kernel, the following vulnerability has been resolved:
btrfs: do not clean up repair bio if submit fails
The submit helper will always run bio_endio() on the bio if it fails to
submit, so cleaning up the bio just leads to a variety of use-after-free
and NULL pointer dereference bugs because we race with the endio
function that is cleaning up the bio. Instead just return BLK_STS_OK as
the repair function has to continue to process the rest of the pages,
and the endio for the repair bio will do the appropriate cleanup for the
page that it was given.
In the Linux kernel, the following vulnerability has been resolved:
XArray: Fix xas_create_range() when multi-order entry present
If there is already an entry present that is of order >= XA_CHUNK_SHIFT
when we call xas_create_range(), xas_create_range() will misinterpret
that entry as a node and dereference xa_node->parent, generally leading
to a crash that looks something like this:
general protection fault, probably for non-canonical address 0xdffffc0000000001:
0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 PID: 32 Comm: khugepaged Not tainted 5.17.0-rc8-syzkaller-00003-g56e337f2cf13 #0
RIP: 0010:xa_parent_locked include/linux/xarray.h:1207 [inline]
RIP: 0010:xas_create_range+0x2d9/0x6e0 lib/xarray.c:725
It's deterministically reproducable once you know what the problem is,
but producing it in a live kernel requires khugepaged to hit a race.
While the problem has been present since xas_create_range() was
introduced, I'm not aware of a way to hit it before the page cache was
converted to use multi-index entries.