Commit 161f873b authored by Sasha Levin's avatar Sasha Levin Committed by Linus Torvalds
Browse files

vfs: read file_handle only once in handle_to_path



We used to read file_handle twice.  Once to get the amount of extra
bytes, and once to fetch the entire structure.

This may be problematic since we do size verifications only after the
first read, so if the number of extra bytes changes in userspace between
the first and second calls, we'll have an incoherent view of
file_handle.

Instead, read the constant size once, and copy that over to the final
structure without having to re-read it again.
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f18c34e4
......@@ -195,8 +195,9 @@ static int handle_to_path(int mountdirfd, struct file_handle __user *ufh,
goto out_err;
}
/* copy the full handle */
if (copy_from_user(handle, ufh,
sizeof(struct file_handle) +
*handle = f_handle;
if (copy_from_user(&handle->f_handle,
&ufh->f_handle,
f_handle.handle_bytes)) {
retval = -EFAULT;
goto out_handle;
......
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment