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ref: 4577a01c688aa0b9a28c69fd89153cc96808a667
parent: 67583876684ec56b99d71b7480d6bcfa4d1f4c14
author: Christophe Staïesse <chastai@skynet.be>
date: Sun Oct 5 09:42:07 EDT 2014

Fix out of bounds array access on invalid macro arg references

A reference to an invalid macro argument (\ not followed by a digit
between 1 and 9) will cause an access outside of the bounds of the
currentmacroargs array in sym_FindMacroArg().

Macro arg references are processed in two places:

In CopyMacroArg(): called when scanning tokens between "", {} and
arguments of a macro call. The only problem here is that it accepts \0
as valid and so calls sym_FindMacroArg with a invalid value.

In PutMacroArg(): called by the lexer automata when it encounters a
token matching \\[0-9]? (in other cases than above). So not only it
accepts \0 but also \ alone.
  Memo: In setuplex(), a rule is defined with a regex composed of up to
    three ranges of chars and takes the form:
      [FirstRange]
      or [FirstRange][SecondRange]?
      or [FirstRange]([SecondRange][Range]*)?
    On scanning, when several rules match, the first longuest one is
    choosen.

Regression test:
1)
SECTION "HOME", HOME
	db "\0"

2)
SECTION "HOME", HOME
	db \A

3)
SECTION "HOME", HOME
	db \

--- a/src/asm/globlex.c

+++ b/src/asm/globlex.c

@@ -208,10 +208,14 @@

 	char *s;

 	yyskipbytes(size);

-	if ((s = sym_FindMacroArg(src[1] - '0')) != NULL) {

-		yyunputstr(s);

+	if ((size == 2 && src[1] >= '1' && src[1] <= '9')) {

+		if ((s = sym_FindMacroArg(src[1] - '0')) != NULL) {

+			yyunputstr(s);

+		} else {

+			yyerror("Macro argument not defined");

+		}

 	} else {

-		yyerror("Macro argument not defined");

+		yyerror("Invalid macro argument");

 	}

 	return (0);

 }

@@ -387,7 +391,7 @@

 	    id = lex_FloatAlloc(&tMacroArgToken);

 	lex_FloatAddFirstRange(id, '\\', '\\');

-	lex_FloatAddSecondRange(id, '0', '9');

+	lex_FloatAddSecondRange(id, '1', '9');

 	id = lex_FloatAlloc(&tMacroUniqueToken);

 	lex_FloatAddFirstRange(id, '\\', '\\');

 	lex_FloatAddSecondRange(id, '@', '@');

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

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

@@ -437,7 +437,6 @@

 	int argNum;

 	switch (c) {

-	case '0':

 	case '1':

 	case '2':

 	case '3':

-- 

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