Merge pull request #198 from ctrlcctrlv/CVE_2019_1000032

Fix decimal values in color fields (nsvg__parseColorRGB, nsvg__parseColorHex)

src/nanosvg.h

@@ -225,11 +225,6 @@ static int nsvg__isdigit(char c)
 	return c >= '0' && c <= '9';
 }
 
-static int nsvg__isnum(char c)
-{
-	return strchr("0123456789+-.eE", c) != 0;
-}
-
 static NSVG_INLINE float nsvg__minf(float a, float b) { return a < b ? a : b; }
 static NSVG_INLINE float nsvg__maxf(float a, float b) { return a > b ? a : b; }
 
@@ -736,9 +731,11 @@ static void nsvg__lineTo(NSVGparser* p, float x, float y)
 
 static void nsvg__cubicBezTo(NSVGparser* p, float cpx1, float cpy1, float cpx2, float cpy2, float x, float y)
 {
-	nsvg__addPoint(p, cpx1, cpy1);
-	nsvg__addPoint(p, cpx2, cpy2);
-	nsvg__addPoint(p, x, y);
+	if (p->npts > 0) {
+		nsvg__addPoint(p, cpx1, cpy1);
+		nsvg__addPoint(p, cpx2, cpy2);
+		nsvg__addPoint(p, x, y);
+	}
 }
 
 static NSVGattrib* nsvg__getAttr(NSVGparser* p)
@@ -808,7 +805,9 @@ static float nsvg__convertToPixels(NSVGparser* p, NSVGcoordinate c, float orig,
 static NSVGgradientData* nsvg__findGradientData(NSVGparser* p, const char* id)
 {
 	NSVGgradientData* grad = p->gradients;
-	while (grad) {
+	if (id == NULL || *id == '\0')
+		return NULL;
+	while (grad != NULL) {
 		if (strcmp(grad->id, id) == 0)
 			return grad;
 		grad = grad->next;
@@ -825,19 +824,26 @@ static NSVGgradient* nsvg__createGradient(NSVGparser* p, const char* id, const f
 	NSVGgradient* grad;
 	float ox, oy, sw, sh, sl;
 	int nstops = 0;
+	int refIter;
 
 	data = nsvg__findGradientData(p, id);
 	if (data == NULL) return NULL;
 
 	// TODO: use ref to fill in all unset values too.
 	ref = data;
+	refIter = 0;
 	while (ref != NULL) {
+		NSVGgradientData* nextRef = NULL;
 		if (stops == NULL && ref->stops != NULL) {
 			stops = ref->stops;
 			nstops = ref->nstops;
 			break;
 		}
-		ref = nsvg__findGradientData(p, ref->ref);
+		nextRef = nsvg__findGradientData(p, ref->ref);
+		if (nextRef == ref) break; // prevent infite loops on malformed data
+		ref = nextRef;
+		refIter++;
+		if (refIter > 32) break; // prevent infite loops on malformed data
 	}
 	if (stops == NULL) return NULL;
 
@@ -1040,6 +1046,10 @@ static void nsvg__addPath(NSVGparser* p, char closed)
 	if (closed)
 		nsvg__lineTo(p, p->pts[0], p->pts[1]);
 
+	// Expect 1 + N*3 points (N = number of cubic bezier segments).
+	if ((p->npts % 3) != 1)
+		return;
+
 	path = (NSVGpath*)malloc(sizeof(NSVGpath));
 	if (path == NULL) goto error;
 	memset(path, 0, sizeof(NSVGpath));
@@ -1205,35 +1215,22 @@ static const char* nsvg__getNextPathItem(const char* s, char* it)
 
 static unsigned int nsvg__parseColorHex(const char* str)
 {
-	unsigned int c = 0, r = 0, g = 0, b = 0;
-	int n = 0;
-	str++; // skip #
-	// Calculate number of characters.
-	while(str[n] && !nsvg__isspace(str[n]))
-		n++;
-	if (n == 6) {
-		sscanf(str, "%x", &c);
-	} else if (n == 3) {
-		sscanf(str, "%x", &c);
-		c = (c&0xf) | ((c&0xf0) << 4) | ((c&0xf00) << 8);
-		c |= c<<4;
-	}
-	r = (c >> 16) & 0xff;
-	g = (c >> 8) & 0xff;
-	b = c & 0xff;
-	return NSVG_RGB(r,g,b);
+	unsigned int r=0, g=0, b=0;
+	if (sscanf(str, "#%2x%2x%2x", &r, &g, &b) == 3 )		// 2 digit hex
+		return NSVG_RGB(r, g, b);
+	if (sscanf(str, "#%1x%1x%1x", &r, &g, &b) == 3 )		// 1 digit hex, e.g. #abc -> 0xccbbaa
+		return NSVG_RGB(r*17, g*17, b*17);			// same effect as (r<<4|r), (g<<4|g), ..
+	return NSVG_RGB(128, 128, 128);
 }
 
 static unsigned int nsvg__parseColorRGB(const char* str)
 {
-	int r = -1, g = -1, b = -1;
-	char s1[32]="", s2[32]="";
-	sscanf(str + 4, "%d%[%%, \t]%d%[%%, \t]%d", &r, s1, &g, s2, &b);
-	if (strchr(s1, '%')) {
-		return NSVG_RGB((r*255)/100,(g*255)/100,(b*255)/100);
-	} else {
-		return NSVG_RGB(r,g,b);
-	}
+	unsigned int r=0, g=0, b=0;
+	if (sscanf(str, "rgb(%u, %u, %u)", &r, &g, &b) == 3)		// decimal integers
+		return NSVG_RGB(r, g, b);
+	if (sscanf(str, "rgb(%u%%, %u%%, %u%%)", &r, &g, &b) == 3)	// decimal integer percentage
+		return NSVG_RGB(r*255/100, g*255/100, b*255/100);
+	return NSVG_RGB(128, 128, 128);
 }
 
 typedef struct NSVGNamedColor {
@@ -1458,6 +1455,15 @@ static int nsvg__parseUnits(const char* units)
 	return NSVG_UNITS_USER;
 }
 
+static int nsvg__isCoordinate(const char* s)
+{
+	// optional sign
+	if (*s == '-' || *s == '+')
+		s++;
+	// must have at least one digit, or start by a dot
+	return (nsvg__isdigit(*s) || *s == '.');
+}
+
 static NSVGcoordinate nsvg__parseCoordinateRaw(const char* str)
 {
 	NSVGcoordinate coord = {0, NSVG_UNITS_USER};
@@ -1597,25 +1603,32 @@ static int nsvg__parseRotate(float* xform, const char* str)
 static void nsvg__parseTransform(float* xform, const char* str)
 {
 	float t[6];
+	int len;
 	nsvg__xformIdentity(xform);
 	while (*str)
 	{
 		if (strncmp(str, "matrix", 6) == 0)
-			str += nsvg__parseMatrix(t, str);
+			len = nsvg__parseMatrix(t, str);
 		else if (strncmp(str, "translate", 9) == 0)
-			str += nsvg__parseTranslate(t, str);
+			len = nsvg__parseTranslate(t, str);
 		else if (strncmp(str, "scale", 5) == 0)
-			str += nsvg__parseScale(t, str);
+			len = nsvg__parseScale(t, str);
 		else if (strncmp(str, "rotate", 6) == 0)
-			str += nsvg__parseRotate(t, str);
+			len = nsvg__parseRotate(t, str);
 		else if (strncmp(str, "skewX", 5) == 0)
-			str += nsvg__parseSkewX(t, str);
+			len = nsvg__parseSkewX(t, str);
 		else if (strncmp(str, "skewY", 5) == 0)
-			str += nsvg__parseSkewY(t, str);
+			len = nsvg__parseSkewY(t, str);
 		else{
 			++str;
 			continue;
 		}
+		if (len != 0) {
+			str += len;
+		} else {
+			++str;
+			continue;
+		}
 
 		nsvg__xformPremultiply(xform, t);
 	}
@@ -1876,8 +1889,11 @@ static int nsvg__getArgsPerElement(char cmd)
 		case 'a':
 		case 'A':
 			return 7;
+		case 'z':
+		case 'Z':
+			return 0;
 	}
-	return 0;
+	return -1;
 }
 
 static void nsvg__pathMoveTo(NSVGparser* p, float* cpx, float* cpy, float* args, int rel)
@@ -2158,7 +2174,12 @@ static void nsvg__pathArcTo(NSVGparser* p, float* cpx, float* cpy, float* args,
 	// The loop assumes an iteration per end point (including start and end), this +1.
 	ndivs = (int)(fabsf(da) / (NSVG_PI*0.5f) + 1.0f);
 	hda = (da / (float)ndivs) / 2.0f;
-	kappa = fabsf(4.0f / 3.0f * (1.0f - cosf(hda)) / sinf(hda));
+	// Fix for ticket #179: division by 0: avoid cotangens around 0 (infinite)
+	if ((hda < 1e-3f) && (hda > -1e-3f))
+		hda *= 0.5f;
+	else
+		hda = (1.0f - cosf(hda)) / sinf(hda);
+	kappa = fabsf(4.0f / 3.0f * hda);
 	if (da < 0.0f)
 		kappa = -kappa;
 
@@ -2187,6 +2208,7 @@ static void nsvg__parsePath(NSVGparser* p, const char** attr)
 	float args[10];
 	int nargs;
 	int rargs = 0;
+	char initPoint;
 	float cpx, cpy, cpx2, cpy2;
 	const char* tmp[4];
 	char closedFlag;
@@ -2209,13 +2231,14 @@ static void nsvg__parsePath(NSVGparser* p, const char** attr)
 		nsvg__resetPath(p);
 		cpx = 0; cpy = 0;
 		cpx2 = 0; cpy2 = 0;
+		initPoint = 0;
 		closedFlag = 0;
 		nargs = 0;
 
 		while (*s) {
 			s = nsvg__getNextPathItem(s, item);
 			if (!*item) break;
-			if (nsvg__isnum(item[0])) {
+			if (cmd != '\0' && nsvg__isCoordinate(item)) {
 				if (nargs < 10)
 					args[nargs++] = (float)nsvg__atof(item);
 				if (nargs >= rargs) {
@@ -2228,6 +2251,7 @@ static void nsvg__parsePath(NSVGparser* p, const char** attr)
 							cmd = (cmd == 'm') ? 'l' : 'L';
 							rargs = nsvg__getArgsPerElement(cmd);
 							cpx2 = cpx; cpy2 = cpy;
+							initPoint = 1;
 							break;
 						case 'l':
 						case 'L':
@@ -2277,7 +2301,6 @@ static void nsvg__parsePath(NSVGparser* p, const char** attr)
 				}
 			} else {
 				cmd = item[0];
-				rargs = nsvg__getArgsPerElement(cmd);
 				if (cmd == 'M' || cmd == 'm') {
 					// Commit path.
 					if (p->npts > 0)
@@ -2286,7 +2309,11 @@ static void nsvg__parsePath(NSVGparser* p, const char** attr)
 					nsvg__resetPath(p);
 					closedFlag = 0;
 					nargs = 0;
-				} else if (cmd == 'Z' || cmd == 'z') {
+				} else if (initPoint == 0) {
+					// Do not allow other commands until initial point has been set (moveTo called once).
+					cmd = '\0';
+				}
+				if (cmd == 'Z' || cmd == 'z') {
 					closedFlag = 1;
 					// Commit path.
 					if (p->npts > 0) {
@@ -2302,6 +2329,12 @@ static void nsvg__parsePath(NSVGparser* p, const char** attr)
 					closedFlag = 0;
 					nargs = 0;
 				}
+				rargs = nsvg__getArgsPerElement(cmd);
+				if (rargs == -1) {
+					// Command not recognized
+					cmd = '\0';
+					rargs = 0;
+				}
 			}
 		}
 		// Commit path.