On Sat, Sep 08, 2018 at 04:28:12PM +0200, Arnd Bergmann wrote:
> These are all handled by the random driver, so instead of listing
> each ioctl, we can just use the same function to deal with both
> native and compat commands.
Umm... I don't think it's right -
> .unlocked_ioctl = random_ioctl,
> + .compat_ioctl = random_ioctl,
->compat_ioctl() gets called in
error = f.file->f_op->compat_ioctl(f.file, cmd, arg);
so you do *NOT* get compat_ptr() for those - they have to do it on their
own. It's not hard to provide a proper compat_ioctl() instance for that
one, but this is not it. What you need in drivers/char/random.c part of
that one is something like
diff --git a/drivers/char/random.c b/drivers/char/random.c
index bf5f99fc36f1..1de75c784cf6 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1954,10 +1954,9 @@ static ssize_t random_write(struct file *file, const char __user *buffer,
return (ssize_t)count;
}
-static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
+static long __random_ioctl(struct file *f, unsigned int cmd, int __user *p)
{
int size, ent_count;
- int __user *p = (int __user *)arg;
int retval;
switch (cmd) {
@@ -2011,6 +2010,18 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
}
}
+static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
+{
+ return __random_ioctl(f, cmd, (int __user *)arg);
+}
+
+#ifdef CONFIG_COMPAT
+static long compat_random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
+{
+ return __random_ioctl(f, cmd, compat_ptr(arg));
+}
+#endif
+
static int random_fasync(int fd, struct file *filp, int on)
{
return fasync_helper(fd, filp, on, &fasync);
@@ -2021,6 +2032,9 @@ const struct file_operations random_fops = {
.write = random_write,
.poll = random_poll,
.unlocked_ioctl = random_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = compat_random_ioctl,
+#endif
.fasync = random_fasync,
.llseek = noop_llseek,
};
