exfat: check if cluster num is valid - linux-dev - Linux kernel development work

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author	Tadeusz Struk <tadeusz.struk@linaro.org>	2022-05-17 08:13:08 +0900
committer	Namjae Jeon <linkinjeon@kernel.org>	2022-05-23 11:17:30 +0900
commit	64ba4b15e5c045f8b746c6da5fc9be9a6b00b61d (patch)
tree	b53623781c1ada35c64ad9e3d3dad7d66be1b1bb /include/asm-m68k/git:/ssh:/git@git.zx2c4.com
parent	exfat: reduce block requests when zeroing a cluster (diff)

exfat: check if cluster num is valid

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: 1e49a94cf707 ("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>

Diffstat (limited to 'include/asm-m68k/git:/ssh:/git@git.zx2c4.com')

0 files changed, 0 insertions, 0 deletions

/* Copyright (C) 2000 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ #include <errno.h> #include <sys/mman.h> /* Open shared memory object. */ int shm_open (const char *name, int oflag, mode_t mode) { __set_errno (ENOSYS); return -1; } stub_warning (shm_open)


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