refactor(legacy): move wait_random into separate file

legacy/Makefile

@@ -7,6 +7,7 @@ OBJS += common.o
 OBJS += flash.o
 OBJS += layout.o
 OBJS += oled.o
+OBJS += random_delays.o
 OBJS += rng.o
 
 ifneq ($(EMULATOR),1)

legacy/common.c

@@ -85,23 +85,6 @@ void __assert_func(const char *file, int line, const char *func,
 
 void hal_delay(uint32_t ms) { usbSleep(ms); }
 
-void wait_random(void) {
-  int wait = random32() & 0xff;
-  volatile int i = 0;
-  volatile int j = wait;
-  while (i < wait) {
-    if (i + j != wait) {
-      shutdown();
-    }
-    ++i;
-    --j;
-  }
-  // Double-check loop completion.
-  if (i != wait || j != 0) {
-    shutdown();
-  }
-}
-
 void drbg_init() {
   uint8_t entropy[48] = {0};
   random_buffer(entropy, sizeof(entropy));

legacy/common.h

@@ -41,8 +41,6 @@ error_shutdown(const char *line1, const char *line2, const char *line3,
 
 void hal_delay(uint32_t ms);
 
-void wait_random(void);
-
 void drbg_init(void);
 void drbg_reseed(const uint8_t *entropy, size_t len);
 void drbg_generate(uint8_t *buf, size_t len);

legacy/firmware/usb.c

@@ -24,6 +24,7 @@
 #include "config.h"
 #include "debug.h"
 #include "messages.h"
+#include "random_delays.h"
 #include "timer.h"
 #include "trezor.h"
 #if U2F_ENABLED

legacy/random_delays.c

@@ -0,0 +1,41 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (c) SatoshiLabs
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "random_delays.h"
+
+#include "common.h"
+#include "rng.h"
+#include "util.h"
+
+void wait_random(void) {
+  int wait = random32() & 0xff;
+  volatile int i = 0;
+  volatile int j = wait;
+  while (i < wait) {
+    if (i + j != wait) {
+      shutdown();
+    }
+    ++i;
+    --j;
+  }
+  // Double-check loop completion.
+  if (i != wait || j != 0) {
+    shutdown();
+  }
+}

legacy/random_delays.h

@@ -0,0 +1,24 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (c) SatoshiLabs
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __RANDOM_DELAYS_H__
+#define __RANDOM_DELAYS_H__
+
+void wait_random(void);
+#endif

legacy/usb21_standard.c

@@ -19,7 +19,7 @@
 #include "usb21_standard.h"
 #include <stdint.h>
 #include <string.h>
-#include "common.h"
+#include "random_delays.h"
 #include "util.h"
 
 static uint16_t build_bos_descriptor(const struct usb_bos_descriptor *bos,

legacy/usb_standard.c

@@ -38,7 +38,7 @@ LGPL License Terms @ref lgpl_license
 
 #include <string.h>
 #include <libopencm3/usb/usbd.h>
-#include "common.h"
+#include "random_delays.h"
 #include "usb_private.h"
 #include "util.h"
 

legacy/webusb.c

@@ -18,7 +18,7 @@
 
 #include <string.h>
 
-#include "common.h"
+#include "random_delays.h"
 #include "usb21_standard.h"
 #include "util.h"
 #include "webusb.h"

legacy/winusb.c

@@ -18,7 +18,7 @@
 
 #include "winusb.h"
 #include <libopencm3/usb/usbd.h>
-#include "common.h"
+#include "random_delays.h"
 #include "util.h"
 
 static int usb_descriptor_type(uint16_t wValue) { return wValue >> 8; }