In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix kmemleak warning for percpu hashmap
Vlad Poenaru reported the following kmemleak issue:
unreferenced object 0x606fd7c44ac8 (size 32):
backtrace (crc 0):
pcpu_alloc_noprof+0x730/0xeb0
bpf_map_alloc_percpu+0x69/0xc0
prealloc_init+0x9d/0x1b0
htab_map_alloc+0x363/0x510
map_create+0x215/0x3a0
__sys_bpf+0x16b/0x3e0
__x64_sys_bpf+0x18/0x20
do_syscall_64+0x7b/0x150
entry_SYSCALL_64_after_hwframe+0x4b/0x53
Further investigation shows the reason is due to not 8-byte aligned
store of percpu pointer in htab_elem_set_ptr():
*(void __percpu **)(l->key + key_size) = pptr;
Note that the whole htab_elem alignment is 8 (for x86_64). If the key_size
is 4, that means pptr is stored in a location which is 4 byte aligned but
not 8 byte aligned. In mm/kmemleak.c, scan_block() scans the memory based
on 8 byte stride, so it won't detect above pptr, hence reporting the memory
leak.
In htab_map_alloc(), we already have
htab->elem_size = sizeof(struct htab_elem) +
round_up(htab->map.key_size, 8);
if (percpu)
htab->elem_size += sizeof(void *);
else
htab->elem_size += round_up(htab->map.value_size, 8);
So storing pptr with 8-byte alignment won't cause any problem and can fix
kmemleak too.
The issue can be reproduced with bpf selftest as well:
1. Enable CONFIG_DEBUG_KMEMLEAK config
2. Add a getchar() before skel destroy in test_hash_map() in prog_tests/for_each.c.
The purpose is to keep map available so kmemleak can be detected.
3. run './test_progs -t for_each/hash_map &' and a kmemleak should be reported.
In the Linux kernel, the following vulnerability has been resolved:
driver core: fix potential NULL pointer dereference in dev_uevent()
If userspace reads "uevent" device attribute at the same time as another
threads unbinds the device from its driver, change to dev->driver from a
valid pointer to NULL may result in crash. Fix this by using READ_ONCE()
when fetching the pointer, and take bus' drivers klist lock to make sure
driver instance will not disappear while we access it.
Use WRITE_ONCE() when setting the driver pointer to ensure there is no
tearing.
In the Linux kernel, the following vulnerability has been resolved:
scsi: target: Fix WRITE_SAME No Data Buffer crash
In newer version of the SBC specs, we have a NDOB bit that indicates there
is no data buffer that gets written out. If this bit is set using commands
like "sg_write_same --ndob" we will crash in target_core_iblock/file's
execute_write_same handlers when we go to access the se_cmd->t_data_sg
because its NULL.
This patch adds a check for the NDOB bit in the common WRITE SAME code
because we don't support it. And, it adds a check for zero SG elements in
each handler in case the initiator tries to send a normal WRITE SAME with
no data buffer.
In the Linux kernel, the following vulnerability has been resolved:
fs: prevent out-of-bounds array speculation when closing a file descriptor
Google-Bug-Id: 114199369
In the Linux kernel, the following vulnerability has been resolved:
ext4: zero i_disksize when initializing the bootloader inode
If the boot loader inode has never been used before, the
EXT4_IOC_SWAP_BOOT inode will initialize it, including setting the
i_size to 0. However, if the "never before used" boot loader has a
non-zero i_size, then i_disksize will be non-zero, and the
inconsistency between i_size and i_disksize can trigger a kernel
warning:
WARNING: CPU: 0 PID: 2580 at fs/ext4/file.c:319
CPU: 0 PID: 2580 Comm: bb Not tainted 6.3.0-rc1-00004-g703695902cfa
RIP: 0010:ext4_file_write_iter+0xbc7/0xd10
Call Trace:
vfs_write+0x3b1/0x5c0
ksys_write+0x77/0x160
__x64_sys_write+0x22/0x30
do_syscall_64+0x39/0x80
Reproducer:
1. create corrupted image and mount it:
mke2fs -t ext4 /tmp/foo.img 200
debugfs -wR "sif <5> size 25700" /tmp/foo.img
mount -t ext4 /tmp/foo.img /mnt
cd /mnt
echo 123 > file
2. Run the reproducer program:
posix_memalign(&buf, 1024, 1024)
fd = open("file", O_RDWR | O_DIRECT);
ioctl(fd, EXT4_IOC_SWAP_BOOT);
write(fd, buf, 1024);
Fix this by setting i_disksize as well as i_size to zero when
initiaizing the boot loader inode.
In the Linux kernel, the following vulnerability has been resolved:
ext4: update s_journal_inum if it changes after journal replay
When mounting a crafted ext4 image, s_journal_inum may change after journal
replay, which is obviously unreasonable because we have successfully loaded
and replayed the journal through the old s_journal_inum. And the new
s_journal_inum bypasses some of the checks in ext4_get_journal(), which
may trigger a null pointer dereference problem. So if s_journal_inum
changes after the journal replay, we ignore the change, and rewrite the
current journal_inum to the superblock.
In the Linux kernel, the following vulnerability has been resolved:
powerpc/iommu: fix memory leak with using debugfs_lookup()
When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time. To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix task hung in ext4_xattr_delete_inode
Syzbot reported a hung task problem:
==================================================================
INFO: task syz-executor232:5073 blocked for more than 143 seconds.
Not tainted 6.2.0-rc2-syzkaller-00024-g512dee0c00ad #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-exec232 state:D stack:21024 pid:5073 ppid:5072 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x995/0xe20 kernel/sched/core.c:6555
schedule+0xcb/0x190 kernel/sched/core.c:6631
__wait_on_freeing_inode fs/inode.c:2196 [inline]
find_inode_fast+0x35a/0x4c0 fs/inode.c:950
iget_locked+0xb1/0x830 fs/inode.c:1273
__ext4_iget+0x22e/0x3ed0 fs/ext4/inode.c:4861
ext4_xattr_inode_iget+0x68/0x4e0 fs/ext4/xattr.c:389
ext4_xattr_inode_dec_ref_all+0x1a7/0xe50 fs/ext4/xattr.c:1148
ext4_xattr_delete_inode+0xb04/0xcd0 fs/ext4/xattr.c:2880
ext4_evict_inode+0xd7c/0x10b0 fs/ext4/inode.c:296
evict+0x2a4/0x620 fs/inode.c:664
ext4_orphan_cleanup+0xb60/0x1340 fs/ext4/orphan.c:474
__ext4_fill_super fs/ext4/super.c:5516 [inline]
ext4_fill_super+0x81cd/0x8700 fs/ext4/super.c:5644
get_tree_bdev+0x400/0x620 fs/super.c:1282
vfs_get_tree+0x88/0x270 fs/super.c:1489
do_new_mount+0x289/0xad0 fs/namespace.c:3145
do_mount fs/namespace.c:3488 [inline]
__do_sys_mount fs/namespace.c:3697 [inline]
__se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3674
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fa5406fd5ea
RSP: 002b:00007ffc7232f968 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fa5406fd5ea
RDX: 0000000020000440 RSI: 0000000020000000 RDI: 00007ffc7232f970
RBP: 00007ffc7232f970 R08: 00007ffc7232f9b0 R09: 0000000000000432
R10: 0000000000804a03 R11: 0000000000000202 R12: 0000000000000004
R13: 0000555556a7a2c0 R14: 00007ffc7232f9b0 R15: 0000000000000000
</TASK>
==================================================================
The problem is that the inode contains an xattr entry with ea_inum of 15
when cleaning up an orphan inode <15>. When evict inode <15>, the reference
counting of the corresponding EA inode is decreased. When EA inode <15> is
found by find_inode_fast() in __ext4_iget(), it is found that the EA inode
holds the I_FREEING flag and waits for the EA inode to complete deletion.
As a result, when inode <15> is being deleted, we wait for inode <15> to
complete the deletion, resulting in an infinite loop and triggering Hung
Task. To solve this problem, we only need to check whether the ino of EA
inode and parent is the same before getting EA inode.