Signal error on field values that cannot be safely represented as strings instead of crashing.

This fixes bug 2845.

svn path=/trunk/; revision=26749

epan/ftypes/ftype-tvbuff.c

@@ -130,7 +130,7 @@ val_repr_len(fvalue_t *fv, ftrepr_t rtype)
 {
 	guint length;
 
-	g_assert(rtype == FTREPR_DFILTER);
+	if (rtype != FTREPR_DFILTER) return -1;
 	length = tvb_length(fv->value.tvb);
 	/* 3 bytes for each byte of the byte "NN:" minus 1 byte
 	 * as there's no trailing ":". */

epan/ftypes/ftypes.c

@@ -303,7 +303,13 @@ fvalue_to_string_repr(fvalue_t *fv, ftrepr_t rtype, char *buf)
 {
 	g_assert(fv->ftype->val_to_string_repr);
 	if (!buf) {
-		buf = g_malloc0(fvalue_string_repr_len(fv, rtype) + 1);
+		int len;
+		if ((len = fvalue_string_repr_len(fv, rtype)) >= 0) {
+			buf = g_malloc0(len + 1);
+		} else {
+			/* the value cannot be represented in the given representation type (rtype) */
+			return NULL;
+		}
 	}
 	fv->ftype->val_to_string_repr(fv, rtype, buf);
 	return buf;

epan/ftypes/ftypes.h

@@ -280,6 +280,9 @@ fvalue_from_string(ftenum_t ftype, char *s, LogFunc logfunc);
 
 /* Returns the length of the string required to hold the
  * string representation of the the field value.
+ *
+ * Returns -1 if the string cannot be represented in the given rtype.
+ *
  * The length DOES NOT include the terminating NUL. */
 int
 fvalue_string_repr_len(fvalue_t *fv, ftrepr_t rtype);
@@ -291,7 +294,9 @@ fvalue_string_repr_len(fvalue_t *fv, ftrepr_t rtype);
  * The pointer to the beginning of the string representation is
  * returned. If 'buf' was NULL, this points to the newly-allocated
  * memory. if 'buf' was non-NULL, then the return value will be
- * 'buf'. */
+ * 'buf'. 
+ *
+ * Returns NULL if the string cannot be represented in the given rtype.*/
 extern char *
 fvalue_to_string_repr(fvalue_t *fv, ftrepr_t rtype, char *buf);
 

epan/wslua/wslua_field.c

@@ -125,9 +125,15 @@ WSLUA_METAMETHOD FieldInfo__call(lua_State* L) {
 			return 1;
 		}
 		case FT_STRING:
-		case FT_STRINGZ:
+		case FT_STRINGZ: {
-			lua_pushstring(L,fvalue_to_string_repr(&fi->value,FTREPR_DISPLAY,NULL));
+			gchar* repr = fvalue_to_string_repr(&fi->value,FTREPR_DISPLAY,NULL);
+			if (repr) 
+				lua_pushstring(L,repr);
+			else
+				luaL_error(L,"field cannot be represented as string because it may contain invalid characters");
+			
 			return 1;
+		}
 		case FT_BYTES:
 		case FT_UINT_BYTES:
 		case FT_GUID:
@@ -147,9 +153,13 @@ WSLUA_METAMETHOD FieldInfo__tostring(lua_State* L) {
 	/* the string representation of the field */
 	FieldInfo fi = checkFieldInfo(L,1);
 	if (fi) {
-		if (fi->value.ftype->val_to_string_repr)
+		if (fi->value.ftype->val_to_string_repr) {
-			lua_pushstring(L,fvalue_to_string_repr(&fi->value,FTREPR_DISPLAY,NULL));
+			gchar* repr = fvalue_to_string_repr(&fi->value,FTREPR_DISPLAY,NULL);
+			if (repr) 
+				lua_pushstring(L,repr);
 			else
+				luaL_error(L,"field cannot be represented as string because it may contain invalid characters");
+		} else
 			luaL_error(L,"field has no string representation");
 	}
 	return 1;