From ba6d9c1a971db3c42bf0b054ebb64f72b3e3ddba Mon Sep 17 00:00:00 2001
From: Dean Camera <dean@fourwalledcubicle.com>
Date: Mon, 22 Jan 2018 16:14:44 +1100
Subject: Fixed bootloaders accepting flash writes to the bootloader region
 (thanks to NicoHood).

---
 Bootloaders/CDC/BootloaderAPI.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

(limited to 'Bootloaders/CDC/BootloaderAPI.c')

diff --git a/Bootloaders/CDC/BootloaderAPI.c b/Bootloaders/CDC/BootloaderAPI.c
index 5e8083ed3..c1e76d3bd 100644
--- a/Bootloaders/CDC/BootloaderAPI.c
+++ b/Bootloaders/CDC/BootloaderAPI.c
@@ -35,8 +35,20 @@
 
 #include "BootloaderAPI.h"
 
+static bool IsPageAddressValid(const uint32_t Address)
+{
+	/* Determine if the given page address is correctly aligned to the
+	   start of a flash page. */
+	bool PageAddressIsAligned = !(Address & (SPM_PAGESIZE - 1));
+
+	return (Address < BOOT_START_ADDR) && PageAddressIsAligned;
+}
+
 void BootloaderAPI_ErasePage(const uint32_t Address)
 {
+	if (! IsPageAddressValid(Address))
+		return;
+
 	ATOMIC_BLOCK(ATOMIC_RESTORESTATE)
 	{
 		boot_page_erase_safe(Address);
@@ -47,6 +59,9 @@ void BootloaderAPI_ErasePage(const uint32_t Address)
 
 void BootloaderAPI_WritePage(const uint32_t Address)
 {
+	if (! IsPageAddressValid(Address))
+		return;
+
 	ATOMIC_BLOCK(ATOMIC_RESTORESTATE)
 	{
 		boot_page_write_safe(Address);
-- 
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