core: use size-limited string formatting functions

Author: negativeExponent

libretro/libretro.c

@@ -4,6 +4,8 @@
 #include <stdarg.h>
 #include <ctype.h>
 
+#include <compat/strl.h>
+
 #ifdef _MSC_VER
 #include <compat/msvc.h>
 #endif
@@ -1865,8 +1867,8 @@ void retro_cheat_set(unsigned index, bool enabled, const char *code) {
 		return;
 	}
 
-	sprintf(name, "N/A");
-	strcpy(temp, code);
+	strlcpy(name, "N/A", sizeof(name));
+	strlcpy(temp, code, sizeof(temp));
 	codepart = strtok(temp, "+,;._ ");
 
 	while (codepart) {

libretro/libretro_dipswitch.c

@@ -1109,10 +1109,22 @@ static void make_core_options(struct retro_core_option_v2_definition *vs_core_op
       memset(&vs_core_options[i], 0,
             sizeof(struct retro_core_option_v2_definition));
 
-      /* Set core key and sanitize string */
-      sprintf(key, "fceumm_next_dipswitch_%s-%s", game_name, option_name);
-      core_key[i] = calloc(strlen(key) + 1, sizeof(char));
-      strcpy(core_key[i], key);
+      /* Set core key and sanitize string. Build "fceumm_dipswitch_<game>-<option>"
+       * with strlcpy/strlcat instead of snprintf, since snprintf isn't
+       * available on pre-MSVC2015 unless compat_snprintf.c is linked
+       * (some build configurations omit it). strlcpy/strlcat truncate
+       * safely if the inputs together would overflow key[]. */
+      strlcpy(key, "fceumm_dipswitch_", sizeof(key));
+      strlcat(key, game_name,            sizeof(key));
+      strlcat(key, "-",                  sizeof(key));
+      strlcat(key, option_name,          sizeof(key));
+      {
+         size_t key_size = strlen(key) + 1;
+         core_key[i] = calloc(key_size, sizeof(char));
+         if (!core_key[i])
+            continue;
+         strlcpy(core_key[i], key, key_size);
+      }
       vs_core_options[i].key = str_to_corekey(core_key[i]);
 
       /* Set desc */

src/cheat.c

@@ -23,6 +23,8 @@
 #include <string.h>
 #include <ctype.h>
 
+#include <compat/strl.h>
+
 #include "fceu-types.h"
 #include "x6502.h"
 #include "cheat.h"
@@ -202,12 +204,13 @@ void FCEU_ResetCheats(void)
 
 int FCEUI_AddCheat(const char *name, uint32_t addr, uint8_t val, int compare, int type) {
 	char *t;
+	size_t n = strlen(name) + 1;
 
 	if (!(t = (char*)malloc(strlen(name) + 1))) {
 		CheatMemErr();
 		return(0);
 	}
-	strcpy(t, name);
+	strlcpy(t, name, n);
 	if (!AddCheatEntry(t, addr, val, compare, 1, type)) {
 		free(t);
 		return(0);
@@ -423,10 +426,11 @@ int FCEUI_SetCheat(uint32_t which, const char *name, int32_t a, int32_t v, int c
 		if (x == which) {
 			if (name) {
 				char *t;
+				size_t n = strlen(name) + 1;
 
-				if ((t = (char*)realloc(next->name, strlen(name) + 1))) {
+				if ((t = (char*)realloc(next->name, n))) {
 					next->name = t;
-					strcpy(next->name, name);
+					strlcpy(next->name, name, n);
 				} else
 					return(0);
 			}

src/general.c

@@ -22,6 +22,8 @@
 #include <string.h>
 #include <stdarg.h>
 
+#include <compat/strl.h>
+
 #include <sys/types.h>
 #include <sys/stat.h>
 #ifdef _WIN32
@@ -45,13 +47,13 @@
 static char BaseDirectory[2048] = { 0 };
 
 void FCEUI_SetBaseDirectory(const char *dir) {
-	strncpy(BaseDirectory, dir, 2047);
-	BaseDirectory[2047] = 0;
+	strlcpy(BaseDirectory, dir, sizeof(BaseDirectory));
 }
 
 char *FCEU_MakeFName(int type, int id1, char *cd1) {
 	char tmp[4096 + 512] = { 0 }; /* +512 for no reason :D */
 	char *ret = 0;
+	size_t len;
 
 	switch (type) {
 	case FCEUMKF_GGROM:
@@ -72,8 +74,10 @@ char *FCEU_MakeFName(int type, int id1, char *cd1) {
 
 	FCEU_printf(" FCEU_MakeFName: %s\n", tmp);
 
-	ret = (char *)FCEU_malloc(strlen(tmp) * sizeof(char) + 1);
-	strcpy(ret, tmp);
+	len = strlen(tmp) + 1;
+	ret = (char *)malloc(len);
+	if (!ret) return NULL;
+	strlcpy(ret, tmp, len);
 
 	return (ret);
 }

src/input/bworld.c

@@ -48,10 +48,19 @@ static void Write(uint8_t V) {
 
 static void Update(void *data, int arg) {
 	if (*(uint8_t*)data) {
+		size_t i;
+		const uint8_t *src = (uint8_t*)data + 1;
 		*(uint8_t*)data = 0;
 		seq = ptr = 0;
 		have = 1;
-		strcpy((char*)bdata, (const char*)((uint8_t*)data + 1));
+		/* bdata is 20 bytes total; bytes 13..19 are filled by the
+		 * memcpy below. Copy at most 13 bytes from `src`, ensuring
+		 * NUL termination at index 13 or earlier. */
+		for (i = 0; i < 13; i++) {
+			if (!src[i]) break;
+			bdata[i] = src[i];
+		}
+		bdata[i] = 0;
 		memcpy((char*)&bdata[13], "SUNSOFT", 7);
 	}
 }

src/nsf.c

@@ -23,6 +23,8 @@
 #include <string.h>
 #include <math.h>
 
+#include <compat/strl.h>
+
 #include "fceu-types.h"
 #include "x6502.h"
 #include "fceu.h"
@@ -166,9 +168,9 @@ static int LoadNSF(FCEUFILE *fp) {
 	/* NULL-terminate strings just in case. */
 	NSFHeader.GameName[31] = NSFHeader.Artist[31] = NSFHeader.Copyright[31] = 0;
 
-	sprintf((char *)NSFInfo->SongName,  "%s", (const char *)NSFHeader.GameName);
-	sprintf((char *)NSFInfo->Artist,    "%s", (const char *)NSFHeader.Artist);
-	sprintf((char *)NSFInfo->Copyright, "%s", (const char *)NSFHeader.Copyright);
+	snprintf((char *)NSFInfo->SongName,  sizeof(NSFInfo->SongName),  "%s", (const char *)NSFHeader.GameName);
+	snprintf((char *)NSFInfo->Artist,    sizeof(NSFInfo->Artist),    "%s", (const char *)NSFHeader.Artist);
+	snprintf((char *)NSFInfo->Copyright, sizeof(NSFInfo->Copyright), "%s", (const char *)NSFHeader.Copyright);
 
 	NSFInfo->LoadAddr = NSFHeader.LoadAddressLow | (NSFHeader.LoadAddressHigh << 8);
 	NSFInfo->InitAddr = NSFHeader.InitAddressLow | (NSFHeader.InitAddressHigh << 8);
@@ -785,7 +787,7 @@ void DrawNSF(uint8_t *target) {
 	} else  {
 		DrawTextTrans(target + 70 * 256 + 4 + (((31 - strlen("Song:")) << 2)), 256, (uint8_t *)"Song:", textColor);
 	}
-	sprintf(snbuf, "<%d/%d>", NSFInfo->CurrentSong + 1, NSFInfo->TotalSongs);
+	snprintf(snbuf, sizeof(snbuf), "<%d/%d>", NSFInfo->CurrentSong + 1, NSFInfo->TotalSongs);
 	DrawTextTrans(target + 82 * 256 + 4 + (((31 - strlen(snbuf)) << 2)), 256, (uint8_t *)snbuf, textColor);
 }
 
@@ -852,8 +854,8 @@ int FCEUI_NSFChange(int amount) {
 
 /* Returns total songs */
 int FCEUI_NSFGetInfo(uint8_t *name, uint8_t *artist, uint8_t *copyright, int maxlen) {
-	strncpy((char *)name, (const char *)NSFInfo->SongName, (size_t)maxlen);
-	strncpy((char *)artist, (const char *)NSFInfo->Artist, (size_t)maxlen);
-	strncpy((char *)copyright, (const char *)NSFInfo->Copyright, (size_t)maxlen);
+	strlcpy((char *)name, (const char *)NSFInfo->SongName, (size_t)maxlen);
+	strlcpy((char *)artist, (const char *)NSFInfo->Artist, (size_t)maxlen);
+	strlcpy((char *)copyright, (const char *)NSFInfo->Copyright, (size_t)maxlen);
 	return (NSFInfo->TotalSongs);
 }

src/unif.c

@@ -26,6 +26,7 @@
 #include <string.h>
 
 #include <file/file_path.h>
+#include <compat/strl.h>
 
 #include "fceu-types.h"
 #include "fceu.h"
@@ -209,12 +210,12 @@ static uint8_t unif_NAME(FCEUFILE *fp) {
 	}
 
 	namebuf[index] = 0;
-	FCEU_printf(" Name: %s\n", namebuf);
-
 	if (!GameInfo->name) {
-		GameInfo->name = FCEU_malloc(strlen(namebuf) + 1);
-		strcpy((char *)GameInfo->name, namebuf);
+		size_t n = strlen(namebuf) + 1;
+		GameInfo->name = FCEU_malloc(n);
+		strlcpy((char *)GameInfo->name, namebuf, n);
 	}
+	FCEU_printf(" Name: %s\n", GameInfo->name);
 	return (1);
 }
 

src/vsuni.c

@@ -20,6 +20,8 @@
 
 #include <string.h>
 
+#include <compat/strl.h>
+
 #include "fceu-types.h"
 #include "x6502.h"
 #include "fceu.h"
@@ -386,7 +388,7 @@ void FCEU_VSUniCheck(uint64_t md5partial, int *MapperNo, int *Mirroring) {
 				GameInfo->input[1] = SI_GAMEPAD;
 			}
 
-			strcpy(name, vs->name);
+			strlcpy(name, vs->name, sizeof(name));
 
 			if (tofix) {
 				FCEU_PrintError(" Incorrect VS-Uni header information!\n");