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:
video: fbdev: sm712fb: Fix crash in smtcfb_write()
When the sm712fb driver writes three bytes to the framebuffer, the
driver will crash:
BUG: unable to handle page fault for address: ffffc90001ffffff
RIP: 0010:smtcfb_write+0x454/0x5b0
Call Trace:
vfs_write+0x291/0xd60
? do_sys_openat2+0x27d/0x350
? __fget_light+0x54/0x340
ksys_write+0xce/0x190
do_syscall_64+0x43/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
Fix it by removing the open-coded endianness fixup-code.
In the Linux kernel, the following vulnerability has been resolved:
ntfs: add sanity check on allocation size
ntfs_read_inode_mount invokes ntfs_malloc_nofs with zero allocation
size. It triggers one BUG in the __ntfs_malloc function.
Fix this by adding sanity check on ni->attr_list_size.
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.