Address issue #142

Also add janet_wrap_number_safe to API.

CHANGELOG.md

@@ -1,6 +1,15 @@
 # Changelog
 All notable changes to this project will be documented in this file.
 
+## Unreleased
+- Fix bug with Nanbox implementation allowing users to created
+  custom values of any type with typed array and marshal modules, which
+  was unsafe.
+- Add `janet_wrap_number_safe` to API, for converting numbers to Janets
+  where the number could be any 64 bit, user provided bit pattern. Certain
+  NaN values (which a machine will never generate as a result of a floating
+  point operation) are guarded against and converted to a default NaN value.
+
 ## 1.1.0 - 2019-07-08
 - Change semantics of `-l` flag to be import rather than dofile.
 - Fix compiler regression in top level defs with destructuring.

src/core/marsh.c

@@ -1070,7 +1070,7 @@ static const uint8_t *unmarshal_one(
 #else
             memcpy(&u.bytes, data + 1, sizeof(double));
 #endif
-            *out = janet_wrap_number(u.d);
+            *out = janet_wrap_number_safe(u.d);
             janet_v_push(st->lookup, *out);
             return data + 9;
         }

src/core/typedarray.c

@@ -197,10 +197,10 @@ static Janet ta_getter(void *p, Janet key) {
                 break;
 #endif
             case JANET_TARRAY_TYPE_F32:
-                value = janet_wrap_number(array->as.f32[i]);
+                value = janet_wrap_number_safe(array->as.f32[i]);
                 break;
             case JANET_TARRAY_TYPE_F64:
-                value = janet_wrap_number(array->as.f64[i]);
+                value = janet_wrap_number_safe(array->as.f64[i]);
                 break;
             default:
                 janet_panicf("cannot get from typed array of type %s",

src/core/wrap.c

@@ -182,6 +182,12 @@ void janet_memempty(JanetKV *mem, int32_t count) {
 
 #ifdef JANET_NANBOX_64
 
+Janet janet_wrap_number_safe(double d) {
+    Janet ret;
+    ret.number = isnan(d) ? (0.0 / 0.0) : d;
+    return ret;
+}
+
 void *janet_nanbox_to_pointer(Janet x) {
     x.i64 &= JANET_NANBOX_PAYLOADBITS;
     return x.pointer;
@@ -222,6 +228,12 @@ Janet janet_wrap_number(double x) {
     return ret;
 }
 
+Janet janet_wrap_number_safe(double d) {
+    Janet ret;
+    double x = isnan(d) ? (0.0 / 0.0) : d;
+    return janet_wrap_number(x);
+}
+
 Janet janet_nanbox32_from_tagi(uint32_t tag, int32_t integer) {
     Janet ret;
     ret.tagged.type = tag;
@@ -243,6 +255,10 @@ double janet_unwrap_number(Janet x) {
 
 #else
 
+Janet janet_wrap_number_safe(double d) {
+    return janet_wrap_number(d);
+}
+
 Janet janet_wrap_nil(void) {
     Janet y;
     y.type = JANET_NIL;
@@ -298,3 +314,4 @@ JANET_WRAP_DEFINE(pointer, void *, JANET_POINTER, pointer)
 #undef JANET_WRAP_DEFINE
 
 #endif
+

src/include/janet.h

@@ -1276,6 +1276,7 @@ JANET_API void janet_put(Janet ds, Janet key, Janet value);
 JANET_API void janet_putindex(Janet ds, int32_t index, Janet value);
 JANET_API uint64_t janet_getflags(const Janet *argv, int32_t n, const char *flags);
 #define janet_flag_at(F, I) ((F) & ((1ULL) << (I)))
+JANET_API Janet janet_wrap_number_safe(double x);
 
 /* VM functions */
 JANET_API int janet_init(void);

test/suite7.janet

@@ -113,4 +113,17 @@
 (check-table-clone @{:a 123 :b 34 :c :hello : 945 0 1 2 3 4 5} "table/clone 1")
 (check-table-clone @{} "table/clone 1")
 
+# Issue #142
+
+(def buffer (tarray/buffer 8))
+(def buffer-float64-view (tarray/new :float64 1 1 0 buffer))
+(def buffer-uint32-view (tarray/new :uint32 2 1 0 buffer))
+
+(set (buffer-uint32-view 1) 0xfffe9234)
+(set (buffer-uint32-view 0) 0x56789abc)
+
+(assert (buffer-float64-view 0) "issue #142 nanbox hijack 1")
+(assert (= (type (buffer-float64-view 0)) :number) "issue #142 nanbox hijack 2")
+(assert (= (type (unmarshal @"\xC8\xbc\x9axV4\x92\xfe\xff")) :number) "issue #142 nanbox hijack 3")
+
 (end-suite)