[PATCH 05/13] fs: check FMODE_WRITE in __kernel_write

[Christoph Hellwig]

We still need to check if the fѕ is open write, even for the low-level
helper.

Signed-off-by: Christoph Hellwig <hch at 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..76be155ad98242 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 (!(file->f_mode & FMODE_WRITE))
+		return -EBADF;
 	if (!(file->f_mode & FMODE_CAN_WRITE))
 		return -EINVAL;
 
-- 
2.26.2