[PATCH 05/14] fs: check FMODE_WRITE in __kernel_write
From: Christoph Hellwig <hch@lst.de>
Date: 2020-06-24 16:16:42
Also in:
linux-fsdevel, lkml, netfilter-devel
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
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 <hch@lst.de> --- fs/read_write.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/fs/read_write.c b/fs/read_write.c
index 2c601d853ff3d8..8f9fc05990ae8b 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;
--
2.26.2