From 334d828c5b55abdeff209d611beab5feec422e79 Mon Sep 17 00:00:00 2001
From: LoRd_MuldeR <mulder2@gmx.de>
Date: Sat, 12 Dec 2020 03:22:29 +0100
Subject: [PATCH] Slightly improved storage of the padding size.

---
 frontend/src/main.c  | 11 ++---------
 frontend/src/utils.h |  4 ++--
 mk-profiled.sh       |  4 ++--
 3 files changed, 6 insertions(+), 13 deletions(-)

diff --git a/frontend/src/main.c b/frontend/src/main.c
index 6ef2858..e5f1296 100644
--- a/frontend/src/main.c
+++ b/frontend/src/main.c
@@ -335,7 +335,7 @@ static int encrypt(const char* const passphrase, const CHR* const input_path, co
 		goto clean_up;
 	}
 
-	SET_NIBBLE(buffer[padding - 1U], padding);
+	SET_LOWBITS(buffer[padding - 1U], padding - 1U);
 	if ((status = slunkcrypt_encrypt_inplace(ctx, buffer, padding)) != SLUNKCRYPT_SUCCESS)
 	{
 		FPUTS((status == SLUNKCRYPT_ABORTED) ? T("\n\nProcess interrupted!\n\n") : T("\n\nSlunkCrypt error: Failed to encrypt data!\n\n"), stderr);
@@ -502,14 +502,7 @@ static int decrypt(const char* const passphrase, const CHR* const input_path, co
 		goto  clean_up;
 	}
 
-	const size_t padding = GET_NIBBLE(buffer[sizeof(uint64_t) - 1U]);
-	if ((!padding) || (padding > sizeof(uint64_t)))
-	{
-		FPRINTF(stderr, T("\n\nPadding error: Erroneous padding length encountered! [0x%02X]\n\n"), (unsigned int)padding);
-		FPUTS(T("Wrong passphrase or corrupted file?\n\n"), stderr);
-		goto clean_up;
-	}
-
+	const size_t padding = GET_LOWBITS(buffer[sizeof(uint64_t) - 1U]) + 1U;
 	if (padding != sizeof(uint64_t))
 	{
 		const size_t count = sizeof(uint64_t) - padding;
diff --git a/frontend/src/utils.h b/frontend/src/utils.h
index 52d316f..5e87c82 100644
--- a/frontend/src/utils.h
+++ b/frontend/src/utils.h
@@ -21,7 +21,7 @@ uint64_t round_down(const uint64_t value, const uint64_t base);
 
 #define ARRAY_SIZE(X) (sizeof((X)) / sizeof(*(X)))
 #define BOUND(MIN,VAL,MAX) (((VAL) < (MIN)) ? (MIN) : (((VAL) > (MAX)) ? (MAX) : (VAL)))
-#define GET_NIBBLE(X) ((X) & 0x0F)
-#define SET_NIBBLE(X, Y) do { X = ((X) & 0xF0) | ((Y) & 0x0F); } while(0)
+#define GET_LOWBITS(X) ((X) & 0x07)
+#define SET_LOWBITS(X, Y) do { X = ((X) & 0xF8) | ((Y) & 0x07); } while(0)
 
 #endif
diff --git a/mk-profiled.sh b/mk-profiled.sh
index fa7dd9b..6780e1b 100755
--- a/mk-profiled.sh
+++ b/mk-profiled.sh
@@ -35,8 +35,8 @@ printf "\n"
 PASSWRD="$(./frontend/bin/slunkcrypt${SUFFIX} --make-pw)"
 
 ./frontend/bin/slunkcrypt${SUFFIX} --self-test
-./frontend/bin/slunkcrypt${SUFFIX} --encrypt "${PASSWRD}" /tmp/${TMP_NAME}.dat /tmp/${TMP_NAME}.enc
-./frontend/bin/slunkcrypt${SUFFIX} --decrypt "${PASSWRD}" /tmp/${TMP_NAME}.enc /tmp/${TMP_NAME}.out
+./frontend/bin/slunkcrypt${SUFFIX} --encrypt ":${PASSWRD}" /tmp/${TMP_NAME}.dat /tmp/${TMP_NAME}.enc
+./frontend/bin/slunkcrypt${SUFFIX} --decrypt ":${PASSWRD}" /tmp/${TMP_NAME}.enc /tmp/${TMP_NAME}.out
 
 printf "\033[1;36m\n------------------------------------------------------------------------------\033[0m\n"
 printf "\033[1;36mRe-compile\n"