exfat: move freeing sbi, upcase table and dropping nls into rcu-delayed helper

That stuff can be accessed by ->d_hash()/->d_compare(); as it is, we have
a hard-to-hit UAF if rcu pathwalk manages to get into ->d_hash() on a filesystem
that is in process of getting shut down.

Besides, having nls and upcase table cleanup moved from ->put_super() towards
the place where sbi is freed makes for simpler failure exits.

Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

exfat: Drop superfluous new line for error messages

exfat_err() adds the new line at the end of the message by itself,
hence the passed string shouldn't contain a new line. Drop the
superfluous newline letters in the error messages in a few places that
have been put mistakenly.

Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: Downgrade ENAMETOOLONG error message to debug messages

The ENAMETOOLONG error message is printed at each time when user tries
to operate with a too long name, and this can flood the kernel logs
easily, as every user can trigger this. Let's downgrade this error
message level to a debug message for suppressing the superfluous
logs.

BugLink: https://bugzilla.suse.com/show_bug.cgi?id=1201725
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: remove argument 'sector' from exfat_get_dentry()

No any function uses argument 'sector', remove it.

Reviewed-by: Andy.Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama, Wataru <wataru.aoyama@sony.com>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Yuezhang.Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

exfat: Avoid allocating upcase table using kcalloc()

The table for Unicode upcase conversion requires an order-5 allocation,
which may fail on a highly-fragmented system:

pool-udisksd: page allocation failure: order:5,
mode:0x40dc0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO), nodemask=(null),
cpuset=/,mems_allowed=0
CPU: 4 PID: 3756880 Comm: pool-udisksd Tainted: G U
5.8.10-200.fc32.x86_64 #1
Hardware name: Dell Inc. XPS 13 9360/0PVG6D, BIOS 2.13.0 11/14/2019
Call Trace:
dump_stack+0x6b/0x88
warn_alloc.cold+0x75/0xd9
? _cond_resched+0x16/0x40
? __alloc_pages_direct_compact+0x144/0x150
__alloc_pages_slowpath.constprop.0+0xcfa/0xd30
? __schedule+0x28a/0x840
? __wait_on_bit_lock+0x92/0xa0
__alloc_pages_nodemask+0x2df/0x320
kmalloc_order+0x1b/0x80
kmalloc_order_trace+0x1d/0xa0
exfat_create_upcase_table+0x115/0x390 [exfat]
exfat_fill_super+0x3ef/0x7f0 [exfat]
? sget_fc+0x1d0/0x240
? exfat_init_fs_context+0x120/0x120 [exfat]
get_tree_bdev+0x15c/0x250
vfs_get_tree+0x25/0xb0
do_mount+0x7c3/0xaf0
? copy_mount_options+0xab/0x180
__x64_sys_mount+0x8e/0xd0
do_syscall_64+0x4d/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Make the driver use kvcalloc() to eliminate the issue.

Fixes: 370e812b3ec1 ("exfat: add nls operations")
Cc: stable@vger.kernel.org #v5.7+
Signed-off-by: Artem Labazov <123321artyom@gmail.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: fix misspellings using codespell tool

Sedat reported typos using codespell tool.

$ codespell fs/exfat/*.c | grep -v iput
fs/exfat/namei.c:293: upto ==> up to
fs/exfat/nls.c:14: tabel ==> table

$ codespell fs/exfat/*.h
fs/exfat/exfat_fs.h:133: usally ==> usually

Fix typos found by codespell.

Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: fix name_hash computation on big endian systems

On-disk format for name_hash field is LE, so it must be explicitly
transformed on BE system for proper result.

Fixes: 370e812b3ec1 ("exfat: add nls operations")
Cc: stable@vger.kernel.org # v5.7
Signed-off-by: Chen Minqiang <ptpt52@gmail.com>
Signed-off-by: Ilya Ponetayev <i.ponetaev@ndmsystems.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: Fix potential use after free in exfat_load_upcase_table()

This code calls brelse(bh) and then dereferences "bh" on the next line
resulting in a possible use after free. The brelse() should just be
moved down a line.

Fixes: b676fdbcf4c8 ("exfat: standardize checksum calculation")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: remove unnecessary reassignment of p_uniname->name_len

kbuild test robot reported :

fs/exfat/nls.c:531:22: warning: Variable 'p_uniname->name_len'
is reassigned a value before the old one has been used.

The reassignment of p_uniname->name_len is not needed and remove it.

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: standardize checksum calculation

To clarify that it is a 16-bit checksum, the parts related to the 16-bit
checksum are renamed and change type to u16.
Furthermore, replace checksum calculation in exfat_load_upcase_table()
with exfat_calc_checksum32().

Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: Remove unused functions exfat_high_surrogate() and exfat_low_surrogate()

After applying previous two patches, these functions are not used anymore.

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: Use a more common logging style

Remove the direct use of KERN_<LEVEL> in functions by creating
separate exfat_<level> macros.

Miscellanea:

o Remove several unnecessary terminating newlines in formats
o Realign arguments and fit to 80 columns where appropriate

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

exfat: add nls operations

This adds the implementation of nls operations for exfat.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>