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linux-stable/fs/exfat
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Tadeusz Struk 7c58b14b6f exfat: check if cluster num is valid 
commit 64ba4b15e5 upstream.

Syzbot reported slab-out-of-bounds read in exfat_clear_bitmap.
This was triggered by reproducer calling truncute with size 0,
which causes the following trace:

BUG: KASAN: slab-out-of-bounds in exfat_clear_bitmap+0x147/0x490 fs/exfat/balloc.c:174
Read of size 8 at addr ffff888115aa9508 by task syz-executor251/365

Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
 print_address_description+0x81/0x3c0 mm/kasan/report.c:233
 __kasan_report mm/kasan/report.c:419 [inline]
 kasan_report+0x1a4/0x1f0 mm/kasan/report.c:436
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309
 exfat_clear_bitmap+0x147/0x490 fs/exfat/balloc.c:174
 exfat_free_cluster+0x25a/0x4a0 fs/exfat/fatent.c:181
 __exfat_truncate+0x99e/0xe00 fs/exfat/file.c:217
 exfat_truncate+0x11b/0x4f0 fs/exfat/file.c:243
 exfat_setattr+0xa03/0xd40 fs/exfat/file.c:339
 notify_change+0xb76/0xe10 fs/attr.c:336
 do_truncate+0x1ea/0x2d0 fs/open.c:65

Move the is_valid_cluster() helper from fatent.c to a common
header to make it reusable in other *.c files. And add is_valid_cluster()
to validate if cluster number is within valid range in exfat_clear_bitmap()
and exfat_set_bitmap().

Link: https://syzkaller.appspot.com/bug?id=50381fc73821ecae743b8cf24b4c9a04776f767c
Reported-by: syzbot+a4087e40b9c13aad7892@syzkaller.appspotmail.com
Fixes: 1e49a94cf7 ("exfat: add bitmap operations")
Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Tadeusz Struk <tadeusz.struk@linaro.org>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 		2022-06-06 08:47:51 +02:00
..
Kconfig exfat: Improve wording of EXFAT_DEFAULT_IOCHARSET config option 2020-06-09 16:48:39 +09:00
Makefile exfat: add Kconfig and Makefile 2020-03-05 21:00:40 -05:00
balloc.c exfat: check if cluster num is valid 2022-06-06 08:47:51 +02:00
cache.c exfat: fix use of uninitialized spinlock on error path 2020-10-07 14:27:13 +09:00
dir.c exfat: remove argument 'sector' from exfat_get_dentry() 2022-01-10 11:00:03 +09:00
exfat_fs.h exfat: check if cluster num is valid 2022-06-06 08:47:51 +02:00
exfat_raw.h exfat: fix shift-out-of-bounds in exfat_fill_super() 2021-02-22 09:55:13 +09:00
fatent.c exfat: check if cluster num is valid 2022-06-06 08:47:51 +02:00
file.c exfat: fix i_blocks for files truncated over 4 GiB 2022-01-10 11:00:02 +09:00
inode.c exfat: fix i_blocks for files truncated over 4 GiB 2022-01-10 11:00:02 +09:00
misc.c exfat: fix missing REQ_SYNC in exfat_update_bhs() 2022-01-10 11:00:04 +09:00
namei.c exfat: remove argument 'sector' from exfat_get_dentry() 2022-01-10 11:00:03 +09:00
nls.c exfat: remove argument 'sector' from exfat_get_dentry() 2022-01-10 11:00:03 +09:00
super.c exfat: move super block magic number to magic.h 2022-01-10 11:00:03 +09:00