From a01ac27be4729f80176a45c54611b768dfbdc840 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 8 May 2020 08:55:03 +0200 Subject: fs: check FMODE_WRITE in __kernel_write Add a WARN_ON_ONCE if the file isn't actually open for write. This matches the check done in vfs_write, but actually warn warns as a kernel user calling write on a file not opened for writing is a pretty obvious programming error. Signed-off-by: Christoph Hellwig --- fs/read_write.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/read_write.c') diff --git a/fs/read_write.c b/fs/read_write.c index 2c601d853ff3..8f9fc05990ae 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -505,6 +505,8 @@ ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t const char __user *p; ssize_t ret; + if (WARN_ON_ONCE(!(file->f_mode & FMODE_WRITE))) + return -EBADF; if (!(file->f_mode & FMODE_CAN_WRITE)) return -EINVAL; -- cgit v1.2.3-59-g8ed1b