f2fs: add a condition to detect overflow in f2fs_ioc_gc_range()

end = range.start + range.len;

If the range.start/range.len is a very large value, then end can overflow
in this operation. It results into a crash in get_valid_blocks() when
accessing the invalid range.start segno.

This issue is reported in ioctl fuzz testing.

Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Sahitya Tummala 2019-09-17 10:19:23 +05:30 committed by Jaegeuk Kim
parent 8223ecc456
commit fbbf779989

View File

@ -2264,9 +2264,9 @@ static int f2fs_ioc_gc_range(struct file *filp, unsigned long arg)
return -EROFS;
end = range.start + range.len;
if (range.start < MAIN_BLKADDR(sbi) || end >= MAX_BLKADDR(sbi)) {
if (end < range.start || range.start < MAIN_BLKADDR(sbi) ||
end >= MAX_BLKADDR(sbi))
return -EINVAL;
}
ret = mnt_want_write_file(filp);
if (ret)