From b7c40f063ff4432e861a36836a62a91b567c0cf4 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Tue, 12 Aug 2025 14:07:54 +0200 Subject: [PATCH] fuse: check if copy_file_range() returns larger than requested size commit e5203209b3935041dac541bc5b37efb44220cc0b upstream. Just like write(), copy_file_range() should check if the return value is less or equal to the requested number of bytes. Reported-by: Chunsheng Luo Closes: https://lore.kernel.org/all/20250807062425.694-1-luochunsheng@ustc.edu/ Fixes: 88bc7d5097a1 ("fuse: add support for copy_file_range()") Cc: # v4.20 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman --- fs/fuse/file.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index f597f7e68e50..260dcaf35123 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -3295,6 +3295,9 @@ static ssize_t __fuse_copy_file_range(struct file *file_in, loff_t pos_in, fc->no_copy_file_range = 1; err = -EOPNOTSUPP; } + if (!err && outarg.size > len) + err = -EIO; + if (err) goto out;