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>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index aea82f2b9240..e4b78fb3fc79 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -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)