From 012c9134d4f6e29c2e13e56490e47a8547d41af7 Mon Sep 17 00:00:00 2001
From: Mounir IDRASSI <mounir.idrassi@idrix.fr>
Date: Sat, 8 Oct 2016 11:12:20 +0200
Subject: define and use own version of secure memory erase macro instead of
 the one coming from VeraCrypt.

---
 DcsCfg/DcsCfgCrypt.c                  |  6 +++---
 DcsInt/DcsInt.c                       | 16 ++++++++--------
 Include/Library/CommonLib.h           |  1 +
 Library/DcsCfgLib/GptEdit.c           |  4 ++--
 Library/PasswordLib/ConsolePassword.c |  2 +-
 Library/PasswordLib/PicturePassword.c |  4 ++--
 6 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/DcsCfg/DcsCfgCrypt.c b/DcsCfg/DcsCfgCrypt.c
index 4b700b6..7295756 100644
--- a/DcsCfg/DcsCfgCrypt.c
+++ b/DcsCfg/DcsCfgCrypt.c
@@ -168,7 +168,7 @@ ChangePassword(
 		}
 		VCAskPwd(AskPwdConfirm, &confirmPassword);
 		if (gAuthPwdCode == AskPwdRetCancel) {
-			burn(&newPassword, sizeof(newPassword));
+			MEM_BURN(&newPassword, sizeof(newPassword));
 			return EFI_NOT_READY;
 		}
 		if (newPassword.Length == confirmPassword.Length) {
@@ -200,8 +200,8 @@ ChangePassword(
 		FALSE);
 		
 		
-	burn(&newPassword, sizeof(newPassword));
-	burn(&confirmPassword, sizeof(confirmPassword));
+	MEM_BURN(&newPassword, sizeof(newPassword));
+	MEM_BURN(&confirmPassword, sizeof(confirmPassword));
 
 	if (vcres != 0) {
 		ERR_PRINT(L"header create error(%x)\n", vcres);
diff --git a/DcsInt/DcsInt.c b/DcsInt/DcsInt.c
index b2fa76c..5d91936 100644
--- a/DcsInt/DcsInt.c
+++ b/DcsInt/DcsInt.c
@@ -156,8 +156,8 @@ PrepareBootParams(
 	SetSecRegionParamsMemory();
 
 	// Clean auth data
-	burn(&gAuthPassword, sizeof(gAuthPassword));
-	burn(&gAuthPim, sizeof(gAuthPim));
+	MEM_BURN(&gAuthPassword, sizeof(gAuthPassword));
+	MEM_BURN(&gAuthPim, sizeof(gAuthPim));
 
 	return EFI_SUCCESS;
 }
@@ -536,7 +536,7 @@ SecRegionChangePwd() {
 		}
 		VCAskPwd(AskPwdConfirm, &confirmPassword);
 		if (gAuthPwdCode == AskPwdRetCancel) {
-			burn(&newPassword, sizeof(newPassword));
+			MEM_BURN(&newPassword, sizeof(newPassword));
 			return EFI_NOT_READY;
 		}
 		if (newPassword.Length == confirmPassword.Length) {
@@ -591,8 +591,8 @@ SecRegionChangePwd() {
 	ERR_PRINT(L"Update (%r)\n", Status);
 
 ret:
-	burn(&newPassword, sizeof(newPassword));
-	burn(&confirmPassword, sizeof(confirmPassword));
+	MEM_BURN(&newPassword, sizeof(newPassword));
+	MEM_BURN(&confirmPassword, sizeof(confirmPassword));
 	return Status;
 }
 
@@ -922,15 +922,15 @@ VirtualNotifyEvent(
 {
 	// Clean all sensible info and keys before transfer to OS
 	if (SecRegionCryptInfo != NULL) {
-		burn(SecRegionCryptInfo, sizeof(*SecRegionCryptInfo));
+		MEM_BURN(SecRegionCryptInfo, sizeof(*SecRegionCryptInfo));
 	}
 
 	if (gRnd != NULL) {
-		burn(gRnd, sizeof(*gRnd));
+		MEM_BURN(gRnd, sizeof(*gRnd));
 	}
 
 	if (SecRegionData != NULL) {
-		burn(SecRegionData, SecRegionSize);
+		MEM_BURN(SecRegionData, SecRegionSize);
 	}
 }
 
diff --git a/Include/Library/CommonLib.h b/Include/Library/CommonLib.h
index 395d4c4..4f28e9b 100644
--- a/Include/Library/CommonLib.h
+++ b/Include/Library/CommonLib.h
@@ -32,6 +32,7 @@ https://opensource.org/licenses/LGPL-3.0
 #define MEM_ALLOC MemAlloc
 #define MEM_FREE MemFree
 #define MEM_REALLOC MemRealloc
+#define MEM_BURN(ptr,count) do { volatile char *burnPtr = (volatile char *)(ptr); size_t burnCount = (size_t) count; while (burnCount--) *burnPtr++ = 0; } while (0)
 
 VOID*
 MemAlloc(
diff --git a/Library/DcsCfgLib/GptEdit.c b/Library/DcsCfgLib/GptEdit.c
index a33d3ca..ea016f1 100644
--- a/Library/DcsCfgLib/GptEdit.c
+++ b/Library/DcsCfgLib/GptEdit.c
@@ -903,8 +903,8 @@ DeListPwdCacheEdit()
 	DePwdCache->CRC = 0;
 	res =gBS->CalculateCrc32(DePwdCache, 512, &crc);
 	DePwdCache->CRC = crc;
-	burn (&pwd, sizeof(pwd));
-	burn (&pim, sizeof(pim));
+	MEM_BURN (&pwd, sizeof(pwd));
+	MEM_BURN (&pim, sizeof(pim));
 	return res;
 }
 
diff --git a/Library/PasswordLib/ConsolePassword.c b/Library/PasswordLib/ConsolePassword.c
index 1b8c48a..fc03d24 100644
--- a/Library/PasswordLib/ConsolePassword.c
+++ b/Library/PasswordLib/ConsolePassword.c
@@ -116,7 +116,7 @@ AskConsolePwdInt(
 	} while (key.UnicodeChar != CHAR_CARRIAGE_RETURN);
 
 	if (length != NULL) *length = count;
-	burn (&key, sizeof (key));
+	MEM_BURN (&key, sizeof (key));
 	// Set end of line
 	if (asciiLine != NULL) {
 		asciiLine[count] = '\0';
diff --git a/Library/PasswordLib/PicturePassword.c b/Library/PasswordLib/PicturePassword.c
index 886ffcd..053a4ad 100644
--- a/Library/PasswordLib/PicturePassword.c
+++ b/Library/PasswordLib/PicturePassword.c
@@ -628,8 +628,8 @@ AskPictPwdInt(
 
 		pwdAction = PwdActNone;
 	} while (TRUE);
-	burn (&key, sizeof (key));
-	burn (&pwdNewChar, sizeof (pwdNewChar));
+	MEM_BURN (&key, sizeof (key));
+	MEM_BURN (&pwdNewChar, sizeof (pwdNewChar));
 	gBS->CloseEvent(InputEvents[1]);
 	gBS->CloseEvent(UpdateEvent);
 	gBS->CloseEvent(BeepOffEvent);
-- 
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