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[njs] Fixed Array.prototype.splice(s, d) when d resizes "this" during eval.

Dmitry Volyntsev
November 10, 2022 08:56PM
details: https://hg.nginx.org/njs/rev/1d6cea817ef4
branches:
changeset: 1996:1d6cea817ef4
user: Dmitry Volyntsev <xeioex@nginx.com>
date: Thu Nov 10 17:53:36 2022 -0800
description:
Fixed Array.prototype.splice(s,d) when d resizes "this" during eval.

This closes #592 and #595 issues on Github.

diffstat:

src/njs_array.c | 116 ++++++++++++++++++----------------------------
src/test/njs_unit_test.c | 21 ++++++++
2 files changed, 67 insertions(+), 70 deletions(-)

diffs (201 lines):

diff -r 5964ac864676 -r 1d6cea817ef4 src/njs_array.c
--- a/src/njs_array.c Thu Nov 10 17:53:35 2022 -0800
+++ b/src/njs_array.c Thu Nov 10 17:53:36 2022 -0800
@@ -274,18 +274,24 @@ static njs_int_t
njs_array_copy_within(njs_vm_t *vm, njs_value_t *array, int64_t to_pos,
int64_t from_pos, int64_t count, njs_bool_t forward)
{
- int64_t i, from, to;
+ int64_t i, from, to, len;
njs_int_t ret;
njs_array_t *arr;
njs_value_t value;

+ njs_assert(to_pos >= 0);
+ njs_assert(from_pos >= 0);
+
if (njs_fast_path(njs_is_fast_array(array) && count > 0)) {
arr = njs_array(array);
-
- memmove(&arr->start[to_pos], &arr->start[from_pos],
- count * sizeof(njs_value_t));
-
- return NJS_OK;
+ len = arr->length;
+
+ if (to_pos + count < len && from_pos + count < len) {
+ memmove(&arr->start[to_pos], &arr->start[from_pos],
+ count * sizeof(njs_value_t));
+
+ return NJS_OK;
+ }
}

if (!forward) {
@@ -1240,15 +1246,19 @@ njs_array_prototype_splice(njs_vm_t *vm,
return NJS_ERROR;
}

- if (njs_fast_path(njs_is_fast_array(this) && deleted->object.fast_array)) {
+ njs_set_array(&del_object, deleted);
+
+ if (njs_fast_path(njs_is_fast_array(this)
+ && deleted->object.fast_array
+ && delete <= deleted->length
+ && start + delete <= njs_array_len(this)))
+ {
array = njs_array(this);
for (i = 0, n = start; i < delete; i++, n++) {
- deleted->start[i] = array->start[n];
+ njs_value_assign(&deleted->start[i], &array->start[n]);
}

} else {
- njs_set_array(&del_object, deleted);
-
for (i = 0, n = start; i < delete; i++, n++) {
ret = njs_value_property_i64(vm, this, n, &value);
if (njs_slow_path(ret == NJS_ERROR)) {
@@ -1256,8 +1266,8 @@ njs_array_prototype_splice(njs_vm_t *vm,
}

if (ret == NJS_OK) {
- /* TODO: CreateDataPropertyOrThrow(). */
- ret = njs_value_property_i64_set(vm, &del_object, i, &value);
+ ret = njs_value_create_data_prop_i64(vm, &del_object, i, &value,
+ 0);
if (njs_slow_path(ret == NJS_ERROR)) {
return ret;
}
@@ -1268,76 +1278,42 @@ njs_array_prototype_splice(njs_vm_t *vm,
}
}
}
-
- ret = njs_object_length_set(vm, &del_object, delete);
- if (njs_slow_path(ret != NJS_OK)) {
- return NJS_ERROR;
- }
+ }
+
+ ret = njs_object_length_set(vm, &del_object, delete);
+ if (njs_slow_path(ret != NJS_OK)) {
+ return NJS_ERROR;
}

- if (njs_fast_path(njs_is_fast_array(this))) {
- array = njs_array(this);
-
- if (delta != 0) {
- /*
- * Relocate the rest of items.
- * Index of the first item is in "n".
- */
- if (delta > 0) {
- ret = njs_array_expand(vm, array, 0, delta);
- if (njs_slow_path(ret != NJS_OK)) {
- return ret;
- }
- }
-
- ret = njs_array_copy_within(vm, this, start + items, start + delete,
- array->length - (start + delete), 0);
- if (njs_slow_path(ret != NJS_OK)) {
- return ret;
- }
-
- array->length += delta;
+ if (delta != 0) {
+ ret = njs_array_copy_within(vm, this, start + items, start + delete,
+ length - (start + delete), delta < 0);
+ if (njs_slow_path(ret != NJS_OK)) {
+ return ret;
}

- /* Copy new items. */
-
- if (items > 0) {
- memcpy(&array->start[start], &args[3],
- items * sizeof(njs_value_t));
- }
-
- } else {
-
- if (delta != 0) {
- ret = njs_array_copy_within(vm, this, start + items, start + delete,
- length - (start + delete), delta < 0);
- if (njs_slow_path(ret != NJS_OK)) {
- return ret;
- }
-
- for (i = length - 1; i >= length + delta; i--) {
- ret = njs_value_property_i64_delete(vm, this, i, NULL);
- if (njs_slow_path(ret == NJS_ERROR)) {
- return NJS_ERROR;
- }
- }
- }
-
- /* Copy new items. */
-
- for (i = 3, n = start; items-- > 0; i++, n++) {
- ret = njs_value_property_i64_set(vm, this, n, &args[i]);
+ for (i = length - 1; i >= length + delta; i--) {
+ ret = njs_value_property_i64_delete(vm, this, i, NULL);
if (njs_slow_path(ret == NJS_ERROR)) {
return NJS_ERROR;
}
}
-
- ret = njs_object_length_set(vm, this, length + delta);
- if (njs_slow_path(ret != NJS_OK)) {
+ }
+
+ /* Copy new items. */
+
+ for (i = 3, n = start; items-- > 0; i++, n++) {
+ ret = njs_value_property_i64_set(vm, this, n, &args[i]);
+ if (njs_slow_path(ret == NJS_ERROR)) {
return NJS_ERROR;
}
}

+ ret = njs_object_length_set(vm, this, length + delta);
+ if (njs_slow_path(ret != NJS_OK)) {
+ return NJS_ERROR;
+ }
+
njs_set_array(&vm->retval, deleted);

return NJS_OK;
diff -r 5964ac864676 -r 1d6cea817ef4 src/test/njs_unit_test.c
--- a/src/test/njs_unit_test.c Thu Nov 10 17:53:35 2022 -0800
+++ b/src/test/njs_unit_test.c Thu Nov 10 17:53:36 2022 -0800
@@ -4980,6 +4980,27 @@ static njs_unit_test_t njs_test[] =
".map(v=>v.join(''))"),
njs_str(",1345,,1,13,13,13") },

+ { njs_str("var a = ['x'];"
+ "var d = a.splice(0, { valueOf() { a.length = 0; return 10; } });"
+ "njs.dump(d)"),
+ njs_str("[<empty>]") },
+
+ { njs_str("var a = ['a', 'b', 'c'];"
+ "var d = a.splice(0, { valueOf() { a.length = 2; return 3; } });"
+ "njs.dump(d)"),
+ njs_str("['a','b',<empty>]") },
+
+#if NJS_HAVE_LARGE_STACK
+ { njs_str("let arr = [ 'x' ];"
+ "let a = { toString() {"
+ " new Float64Array(100).set(["
+ " {toString() {Array.prototype.splice.call(arr, a)}}"
+ " ])"
+ " }};"
+ "a.toString()"),
+ njs_str("RangeError: Maximum call stack size exceeded") },
+#endif
+
{ njs_str("var o = { toString: () => {"
" for (var i = 0; i < 0x10; i++) {a.push(1)};"
" return {};"
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Subject Author Views Posted

[njs] Fixed Array.prototype.splice(s, d) when d resizes "this" during eval.

Dmitry Volyntsev 218 November 10, 2022 08:56PM



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