atm: lift copyin from atm_dev_ioctl()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

net/atm/ioctl.c

@@ -182,7 +182,30 @@ static int do_vcc_ioctl(struct socket *sock, unsigned int cmd,
 		}
 		error = atm_getnames(buf, len);
 	} else {
-		error = atm_dev_ioctl(cmd, argp, compat);
+		int number;
+
+		if (IS_ENABLED(CONFIG_COMPAT) && compat) {
+#ifdef CONFIG_COMPAT
+			struct compat_atmif_sioc __user *csioc = argp;
+			compat_uptr_t carg;
+
+			len = &csioc->length;
+			if (get_user(carg, &csioc->arg))
+				return -EFAULT;
+			buf = compat_ptr(carg);
+			if (get_user(number, &csioc->number))
+				return -EFAULT;
+#endif
+		} else {
+			struct atmif_sioc __user *sioc = argp;
+
+			len = &sioc->length;
+			if (get_user(buf, &sioc->arg))
+				return -EFAULT;
+			if (get_user(number, &sioc->number))
+				return -EFAULT;
+		}
+		error = atm_dev_ioctl(cmd, buf, len, number, compat);
 	}
 
 done:

net/atm/resources.c

@@ -227,39 +227,14 @@ int atm_getnames(void __user *buf, int __user *iobuf_len)
 	return error;
 }
 
-int atm_dev_ioctl(unsigned int cmd, void __user *arg, int compat)
+int atm_dev_ioctl(unsigned int cmd, void __user *buf, int __user *sioc_len,
+		  int number, int compat)
 {
-	void __user *buf;
-	int error, len, number, size = 0;
+	int error, len, size = 0;
 	struct atm_dev *dev;
-	int __user *sioc_len;
 
-	if (IS_ENABLED(CONFIG_COMPAT) && compat) {
-#ifdef CONFIG_COMPAT
-		struct compat_atmif_sioc __user *csioc = arg;
-		compat_uptr_t carg;
-
-		sioc_len = &csioc->length;
-		if (get_user(carg, &csioc->arg))
-			return -EFAULT;
-		buf = compat_ptr(carg);
-
-		if (get_user(len, &csioc->length))
-			return -EFAULT;
-		if (get_user(number, &csioc->number))
-			return -EFAULT;
-#endif
-	} else {
-		struct atmif_sioc __user *sioc = arg;
-
-		sioc_len = &sioc->length;
-		if (get_user(buf, &sioc->arg))
-			return -EFAULT;
-		if (get_user(len, &sioc->length))
-			return -EFAULT;
-		if (get_user(number, &sioc->number))
-			return -EFAULT;
-	}
+	if (get_user(len, sioc_len))
+		return -EFAULT;
 
 	dev = try_then_request_module(atm_dev_lookup(number), "atm-device-%d",
 				      number);

net/atm/resources.h

@@ -15,8 +15,8 @@ extern struct list_head atm_devs;
 extern struct mutex atm_dev_mutex;
 
 int atm_getnames(void __user *buf, int __user *iobuf_len);
-int atm_dev_ioctl(unsigned int cmd, void __user *arg, int compat);
-
+int atm_dev_ioctl(unsigned int cmd, void __user *buf, int __user *sioc_len,
+		  int number, int compat);
 
 #ifdef CONFIG_PROC_FS