rgbasm: Fix TOCTOU and reduce buffering.

Makefile

@@ -22,7 +22,9 @@ rgbasm_obj := \
 	src/asm/output.o \
 	src/asm/rpn.o \
 	src/asm/symbol.o \
-	src/asm/gameboy/locallex.o
+	src/asm/gameboy/locallex.o \
+	src/extern/strlcpy.o \
+	src/extern/strlcat.o
 
 rgblib_obj := \
 	src/lib/library.o \

include/asm/fstack.h

@@ -9,6 +9,8 @@
 #ifndef ASMOTOR_ASM_FSTACK_H
 #define ASMOTOR_ASM_FSTACK_H
 
+#include <stdio.h>
+
 #include "asm/asm.h"
 #include "asm/types.h"
 #include "asm/lexer.h"
@@ -27,14 +29,17 @@ struct sContext {
 	ULONG nREPTBlockSize;
 };
 
-extern ULONG fstk_RunInclude(char *s);
+void
+fstk_RunInclude(char *);
 extern void fstk_RunMacroArg(SLONG s);
-extern ULONG fstk_Init(char *s);
+void
+fstk_Init(char *);
 extern void fstk_Dump(void);
 extern void fstk_AddIncludePath(char *s);
 extern ULONG fstk_RunMacro(char *s);
 extern void fstk_RunRept(ULONG count);
-extern void fstk_FindFile(char *s);
+FILE *
+fstk_FindFile(char *);
 
 extern int yywrap(void);
 

src/asm/fstack.c

@@ -5,10 +5,19 @@
  *
  */
 
+#include <errno.h>
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
+#ifndef STRL_IN_LIBC
+#define strlcpy rgbds_strlcpy
+#define strlcat rgbds_strlcat
+size_t strlcpy(char *, const char *, size_t);
+size_t strlcat(char *, const char *, size_t);
+#endif
+
 #include "asm/symbol.h"
 #include "asm/fstack.h"
 #include "asm/types.h"
@@ -195,28 +204,33 @@ fstk_AddIncludePath(char *s)
 	strcpy(IncludePaths[NextIncPath++], s);
 }
 
-void 
+FILE *
-fstk_FindFile(char *s)
+fstk_FindFile(char *fname)
 {
-	char t[_MAX_PATH + 1];
+	char path[PATH_MAX];
-	SLONG i = -1;
+	int i;
-
-	strcpy(t, s);
-
-	while (i < NextIncPath) {
 	FILE *f;
 
-		if ((f = fopen(t, "rb")) != NULL) {
+	if ((f = fopen(fname, "rb")) != NULL || errno != ENOENT) {
-			fclose(f);
+		return f;
-			strcpy(s, t);
-			return;
 	}
-		i += 1;
+
-		if (i < NextIncPath) {
+	for (i = 0; i < NextIncPath; ++i) {
-			strcpy(t, IncludePaths[i]);
+		if (strlcpy(path, IncludePaths[i], sizeof path) >= 
-			strcat(t, s);
+		    sizeof path) {
+			continue;
+		}
+		if (strlcat(path, fname, sizeof path) >= sizeof path) {
+			continue;
+		}
+
+		if ((f = fopen(path, "rb")) != NULL || errno != ENOENT) {
+			return f;
 		}
 	}
+
+	errno = ENOENT;
+	return NULL;
 }
 /*
  * RGBAsm - FSTACK.C (FileStack routines)
@@ -225,17 +239,20 @@ fstk_FindFile(char *s)
  *
  */
 
-ULONG 
+void
 fstk_RunInclude(char *tzFileName)
 {
 	FILE *f;
 
-	//printf("INCLUDE: %s\n", s);
+	f = fstk_FindFile(tzFileName);
 
-	fstk_FindFile(tzFileName);
+	if (f == NULL) {
-	//printf("INCLUDING: %s\n", tzFileName);
+		fprintf(stderr, "Unable to open included file '%s': ",
+		    tzFileName);
+		perror(NULL);
+		exit(1);
+	}
 
-	if ((f = fopen(tzFileName, "r")) != NULL) {
 	pushcontext();
 	nLineNo = 1;
 	nCurrentStatus = STAT_isInclude;
@@ -248,10 +265,6 @@ fstk_RunInclude(char *tzFileName)
 
 	yyunput('\n');
 	nLineNo -= 1;
-
-		return (1);
-	} else
-		return (0);
 }
 /*
  * RGBAsm - FSTACK.C (FileStack routines)
@@ -360,7 +373,7 @@ fstk_RunRept(ULONG count)
  *
  */
 
-ULONG 
+void
 fstk_Init(char *s)
 {
 	char tzFileName[_MAX_PATH + 1];
@@ -368,17 +381,19 @@ fstk_Init(char *s)
 	sym_AddString("__FILE__", s);
 
 	strcpy(tzFileName, s);
-	fstk_FindFile(tzFileName);
-
 	pFileStack = NULL;
-	if ((pCurrentFile = fopen(tzFileName, "r")) != NULL) {
+	pCurrentFile = fopen(tzFileName, "rb");
+	if (pCurrentFile == NULL) {
+		fprintf(stderr, "Unable to open file '%s': ",
+		    tzFileName);
+		perror(NULL);
+		exit(1);
+	}
+
 	nMacroCount = 0;
 	nCurrentStatus = STAT_isInclude;
 	strcpy(tzCurrentFileName, tzFileName);
 	CurrentFlexHandle = yy_create_buffer(pCurrentFile);
 	yy_switch_to_buffer(CurrentFlexHandle);
 	nLineNo = 1;
-		return (1);
-	} else
-		return (0);
 }

src/asm/main.c

@@ -348,7 +348,6 @@ main(int argc, char *argv[])
 
 	DefaultOptions = CurrentOptions;
 
-	/* tzMainfile=argv[argn++]; argc-=1; */
 	tzMainfile = argv[argc - 1];
 
 	setuplex();
@@ -366,7 +365,7 @@ main(int argc, char *argv[])
 	nPass = 1;
 	nErrors = 0;
 	sym_PrepPass1();
-	if (fstk_Init(tzMainfile)) {
+	fstk_Init(tzMainfile);
 	if (CurrentOptions.verbose) {
 		printf("Pass 1...\n");
 	}
@@ -432,9 +431,5 @@ main(int argc, char *argv[])
 		    nErrors);
 		exit(1);
 	}
-	} else {
+	return 0;
-		printf("File '%s' not found\n", tzMainfile);
-		exit(5);
-	}
-	return (0);
 }

src/asm/output.c

@@ -907,9 +907,14 @@ out_BinaryFile(char *s)
 {
 	FILE *f;
 
-	fstk_FindFile(s);
+	f = fstk_FindFile(s);
+	if (f == NULL) {
+		fprintf(stderr, "Unable to open incbin file '%s': ",
+		    s);
+		perror(NULL);
+		exit(1);
+	}
 
-	if ((f = fopen(s, "rb")) != NULL) {
 	SLONG fsize;
 
 	fseek(f, 0, SEEK_END);
@@ -929,8 +934,6 @@ out_BinaryFile(char *s)
 	nPC += fsize;
 	pPCSymbol->nValue += fsize;
 	fclose(f);
-	} else
-		fatalerror("Could not open file '%s': %s", s, strerror(errno));
 }
 
 void 
@@ -944,9 +947,14 @@ out_BinaryFileSlice(char *s, SLONG start_pos, SLONG length)
 	if (length < 0)
 		fatalerror("Number of bytes to read must be greater than zero");
 
-	fstk_FindFile(s);
+	f = fstk_FindFile(s);
+	if (f == NULL) {
+		fprintf(stderr, "Unable to open included file '%s': ",
+		    s);
+		perror(NULL);
+		exit(1);
+	}
 
-	if ((f = fopen(s, "rb")) != NULL) {
 	SLONG fsize;
 
 	fseek(f, 0, SEEK_END);
@@ -974,6 +982,4 @@ out_BinaryFileSlice(char *s, SLONG start_pos, SLONG length)
 	pPCSymbol->nValue += length;
 
 	fclose(f);
-	} else
-		fatalerror("Could not open file '%s': %s", s, strerror(errno));
 }

src/asm/yaccprt3.y

@@ -265,10 +265,7 @@ set				:	T_LABEL T_POP_SET const
 
 include			:	T_POP_INCLUDE string
 					{
-						if( !fstk_RunInclude($2) )
+						fstk_RunInclude($2);
-						{
-							yyerror("Could not open file '%s' : %s\n", $2, strerror(errno));
-						}
 					}
 ;
 

src/extern/strlcat.c

@@ -0,0 +1,55 @@
+/*	$OpenBSD: strlcat.c,v 1.13 2005/08/08 08:05:37 espie Exp $	*/
+
+/*
+ * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <string.h>
+
+/*
+ * Appends src to string dst of size siz (unlike strncat, siz is the
+ * full size of dst, not space left).  At most siz-1 characters
+ * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
+ * Returns strlen(src) + MIN(siz, strlen(initial dst)).
+ * If retval >= siz, truncation occurred.
+ */
+size_t
+rgbds_strlcat(char *dst, const char *src, size_t siz)
+{
+	char *d = dst;
+	const char *s = src;
+	size_t n = siz;
+	size_t dlen;
+
+	/* Find the end of dst and adjust bytes left but don't go past end */
+	while (n-- != 0 && *d != '\0')
+		d++;
+	dlen = d - dst;
+	n = siz - dlen;
+
+	if (n == 0)
+		return(dlen + strlen(s));
+	while (*s != '\0') {
+		if (n != 1) {
+			*d++ = *s;
+			n--;
+		}
+		s++;
+	}
+	*d = '\0';
+
+	return(dlen + (s - src));	/* count does not include NUL */
+}

src/extern/strlcpy.c

@@ -0,0 +1,51 @@
+/*	$OpenBSD: strlcpy.c,v 1.11 2006/05/05 15:27:38 millert Exp $	*/
+
+/*
+ * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <string.h>
+
+/*
+ * Copy src to string dst of size siz.  At most siz-1 characters
+ * will be copied.  Always NUL terminates (unless siz == 0).
+ * Returns strlen(src); if retval >= siz, truncation occurred.
+ */
+size_t
+rgbds_strlcpy(char *dst, const char *src, size_t siz)
+{
+	char *d = dst;
+	const char *s = src;
+	size_t n = siz;
+
+	/* Copy as many bytes as will fit */
+	if (n != 0) {
+		while (--n != 0) {
+			if ((*d++ = *s++) == '\0')
+				break;
+		}
+	}
+
+	/* Not enough room in dst, add NUL and traverse rest of src */
+	if (n == 0) {
+		if (siz != 0)
+			*d = '\0';		/* NUL-terminate dst */
+		while (*s++)
+			;
+	}
+
+	return(s - src - 1);	/* count does not include NUL */
+}