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Merge pull request #359 from dbrotz/fix-lexer-out-of-bounds

Fix out of bounds array access in lexer

--- a/src/asm/lexer.c

+++ b/src/asm/lexer.c

@@ -38,6 +38,8 @@

 #define SAFETYMARGIN		1024

+#define BOM_SIZE 3

+

 struct sLexFloat tLexFloat[32];

 struct sLexString *tLexHash[LEXHASHSIZE];

 YY_BUFFER_STATE pCurrentBuffer;

@@ -49,6 +51,9 @@

 uint32_t nFloating;

 enum eLexerState lexerstate = LEX_STATE_NORMAL;

+/* UTF-8 byte order mark */

+static const unsigned char bom[BOM_SIZE] = { 0xEF, 0xBB, 0xBF };

+

 void upperstring(char *s)

 {

 	while (*s) {

@@ -120,11 +125,11 @@

  */

 static void yy_buffer_append(YY_BUFFER_STATE buf, uint32_t capacity, char c)

 {

-	assert(buf->pBuffer[buf->nBufferSize] == 0);

+	assert(buf->pBufferStart[buf->nBufferSize] == 0);

 	assert(buf->nBufferSize + 1 < capacity);

-	buf->pBuffer[buf->nBufferSize++] = c;

-	buf->pBuffer[buf->nBufferSize] = 0;

+	buf->pBufferStart[buf->nBufferSize++] = c;

+	buf->pBufferStart[buf->nBufferSize] = 0;

 }

 YY_BUFFER_STATE yy_scan_bytes(char *mem, uint32_t size)

@@ -221,6 +226,11 @@

 	 */

 	capacity += 3;

+	/* Skip UTF-8 byte order mark. */

+	if (pBuffer->nBufferSize >= BOM_SIZE

+	 && !memcmp(pBuffer->pBuffer, bom, BOM_SIZE))

+		pBuffer->pBuffer += BOM_SIZE;

+

 	/* Convert all line endings to LF and spaces */

 	char *mem = pBuffer->pBuffer;

@@ -281,7 +291,7 @@

 	}

 	/* Add newline if file doesn't end with one */

-	if (size == 0 || pBuffer->pBuffer[size - 1] != '\n')

+	if (size == 0 || pBuffer->pBufferStart[size - 1] != '\n')

 		yy_buffer_append(pBuffer, capacity, '\n');

 	/* Add newline if \ will eat the last newline */

@@ -289,10 +299,10 @@

 		size_t pos = pBuffer->nBufferSize - 2;

 		/* Skip spaces */

-		while (pos > 0 && pBuffer->pBuffer[pos] == ' ')

+		while (pos > 0 && pBuffer->pBufferStart[pos] == ' ')

 			pos--;

-		if (pBuffer->pBuffer[pos] == '\\')

+		if (pBuffer->pBufferStart[pos] == '\\')

 			yy_buffer_append(pBuffer, capacity, '\n');

 	}

@@ -471,17 +481,17 @@

 	char *s = pLexBuffer;

 	uint32_t nOldFloatMask = 0;

-	uint32_t nFloatMask = tFloatingFirstChar[(int32_t)*s];

+	uint32_t nFloatMask = tFloatingFirstChar[(uint8_t)*s];

 	if (nFloatMask != 0) {

 		s++;

 		nOldFloatMask = nFloatMask;

-		nFloatMask &= tFloatingSecondChar[(int32_t)*s];

+		nFloatMask &= tFloatingSecondChar[(uint8_t)*s];

 		while (nFloatMask != 0) {

 			s++;

 			nOldFloatMask = nFloatMask;

-			nFloatMask &= tFloatingChars[(int32_t)*s];

+			nFloatMask &= tFloatingChars[(uint8_t)*s];

 		}

 	}

@@ -783,10 +793,22 @@

 		 * numeric literal, string, or bracketed symbol, so just return

 		 * the ASCII character.

 		 */

-		if (*pLexBuffer == '\n')

+		unsigned char ch = *pLexBuffer++;

+

+		if (ch == '\n')

 			AtLineStart = 1;

-		return *pLexBuffer++;

+		/*

+		 * Check for invalid unprintable characters.

+		 * They may not be readily apparent in a text editor,

+		 * so this is useful for identifying encoding problems.

+		 */

+		if (ch != 0

+		 && ch != '\n'

+		 && !(ch >= 0x20 && ch <= 0x7E))

+			fatalerror("Found garbage character: 0x%02X", ch);

+

+		return ch;

 	}

 	if (pLongestFixed == NULL || nFloatLen > pLongestFixed->nNameLength) {

--- /dev/null

+++ b/test/asm/garbage_char.asm

@@ -1,0 +1,1 @@

+x

\ No newline at end of file

--- /dev/null

+++ b/test/asm/garbage_char.out

@@ -1,0 +1,2 @@

+ERROR: garbage_char.asm(1):

+    Found garbage character: 0xFF

--- /dev/null

+++ b/test/asm/garbage_char.out.pipe

@@ -1,0 +1,2 @@

+ERROR: -(1):

+    Found garbage character: 0xFF