linux-stable/fs/squashfs
Phillip Lougher a0aefbeabc squashfs: fix divide error in calculate_skip()
commit d6e621de1f upstream.

Sysbot has reported a "divide error" which has been identified as being
caused by a corrupted file_size value within the file inode.  This value
has been corrupted to a much larger value than expected.

Calculate_skip() is passed i_size_read(inode) >> msblk->block_log.  Due to
the file_size value corruption this overflows the int argument/variable in
that function, leading to the divide error.

This patch changes the function to use u64.  This will accommodate any
unexpectedly large values due to corruption.

The value returned from calculate_skip() is clamped to be never more than
SQUASHFS_CACHED_BLKS - 1, or 7.  So file_size corruption does not lead to
an unexpectedly large return result here.

Link: https://lkml.kernel.org/r/20210507152618.9447-1-phillip@squashfs.org.uk
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Reported-by: <syzbot+e8f781243ce16ac2f962@syzkaller.appspotmail.com>
Reported-by: <syzbot+7b98870d4fec9447b951@syzkaller.appspotmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-22 10:59:45 +02:00
..
block.c
cache.c
decompressor.c
decompressor.h
decompressor_multi.c
decompressor_multi_percpu.c
decompressor_single.c
dir.c
export.c squashfs: fix inode lookup sanity checks 2021-03-30 14:36:59 +02:00
file.c squashfs: fix divide error in calculate_skip() 2021-05-22 10:59:45 +02:00
file_cache.c
file_direct.c
fragment.c
id.c squashfs: fix xattr id and id lookup sanity checks 2021-03-30 14:36:59 +02:00
inode.c
Kconfig
lz4_wrapper.c
lzo_wrapper.c
Makefile
namei.c
page_actor.c
page_actor.h
squashfs.h
squashfs_fs.h squashfs: fix inode lookup sanity checks 2021-03-30 14:36:59 +02:00
squashfs_fs_i.h
squashfs_fs_sb.h squashfs: add more sanity checks in id lookup 2021-02-13 13:51:15 +01:00
super.c squashfs: add more sanity checks in id lookup 2021-02-13 13:51:15 +01:00
symlink.c
xattr.c
xattr.h squashfs: add more sanity checks in id lookup 2021-02-13 13:51:15 +01:00
xattr_id.c squashfs: fix xattr id and id lookup sanity checks 2021-03-30 14:36:59 +02:00
xz_wrapper.c
zlib_wrapper.c
zstd_wrapper.c