staging: android: ashmem: Replace strcpy with strscpy

Replaced strcpy call with safer strscpy call with given length.
This elimates the need to manually null-terminate the given string,
since strscpy will null terminate the destination anyway.:
Signed-off-by: Ole Wiedemann <ole.wiedemann@fau.de>
Co-developed-by: Sebastian Scherbel <sebastian.scherbel@fau.de>
Signed-off-by: Sebastian Scherbel <sebastian.scherbel@fau.de>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Acked-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20191213131032.22579-1-ole.wiedemann@fau.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/ashmem.c

@@ -537,14 +537,14 @@ static int set_name(struct ashmem_area *asma, void __user *name)
 	len = strncpy_from_user(local_name, name, ASHMEM_NAME_LEN);
 	if (len < 0)
 		return len;
-	if (len == ASHMEM_NAME_LEN)
-		local_name[ASHMEM_NAME_LEN - 1] = '\0';
+
 	mutex_lock(&ashmem_mutex);
 	/* cannot change an existing mapping's name */
 	if (asma->file)
 		ret = -EINVAL;
 	else
-		strcpy(asma->name + ASHMEM_NAME_PREFIX_LEN, local_name);
+		strscpy(asma->name + ASHMEM_NAME_PREFIX_LEN, local_name,
+			ASHMEM_NAME_LEN);
 
 	mutex_unlock(&ashmem_mutex);
 	return ret;