pty: make ptmx file ops read-only after init

kees · gregkh · commit d2ec3f77de8e · 2016-09-15T12:47:03.000+02:00
The ptmx_fops structure is only changed during init, so mark it as such.

Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
@@ -800,7 +800,7 @@ static int ptmx_open(struct inode *inode, struct file *filp)
 	return retval;
 }
 
-static struct file_operations ptmx_fops;
+static struct file_operations ptmx_fops __ro_after_init;
 
 static void __init unix98_pty_init(void)
 {

Original file line number	Diff line number	Diff line change
`@@ -800,7 +800,7 @@ static int ptmx_open(struct inode inode, struct file filp)`
`800`	`800`	`return retval;`
`801`	`801`	`}`
`802`	`802`
`803`		`-static struct file_operations ptmx_fops;`
	`803`	`+static struct file_operations ptmx_fops __ro_after_init;`
`804`	`804`
`805`	`805`	`static void __init unix98_pty_init(void)`
`806`	`806`	`{`