Skip to content

Fix SimpleXML integer offsets that cannot resolve aliasing a node #23068

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
iliaal wants to merge 1 commit into from
+121 −15
Closed

Fix SimpleXML integer offsets that cannot resolve aliasing a node #23068

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 4 additions & 0 deletions NEWS
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,10 @@ PHP NEWS
. Fixed bug GH-23043 (broken session id code can cause zend_mm_heap
corrupted). (ndossche)

- SimpleXML:
. Fixed integer element offsets that cannot resolve aliasing an existing
element. (iliaal)

- Sockets:
. Fixed various memory related issues in ext/sockets. (David Carlier)

Expand Down
38 changes: 23 additions & 15 deletions ext/simplexml/simplexml.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -134,7 +134,7 @@ static xmlNodePtr sxe_get_element_by_offset(php_sxe_object *sxe, zend_long offse
return NULL;
}
}
while (node && nodendx <= offset) {
while (node && (offset < 0 || nodendx <= offset)) {
if (node->type == XML_ELEMENT_NODE && match_ns(node, sxe->iter.nsprefix, sxe->iter.isprefix)) {
if (sxe->iter.type == SXE_ITER_CHILD || (
sxe->iter.type == SXE_ITER_ELEMENT && xmlStrEqual(node->name, BAD_CAST ZSTR_VAL(sxe->iter.name)))) {
Expand Down Expand Up @@ -302,14 +302,16 @@ static zval *sxe_prop_dim_read(zend_object *object, zval *member, bool elements,
}
if (!member || Z_TYPE_P(member) == IS_LONG) {
zend_long cnt = 0;
bool appendable = true;
xmlNodePtr mynode = node;

if (sxe->iter.type == SXE_ITER_CHILD) {
node = php_sxe_get_first_node_non_destructive(sxe, node);
}
if (sxe->iter.type == SXE_ITER_NONE) {
if (member && Z_LVAL_P(member) > 0) {
php_error_docref(NULL, E_WARNING, "Cannot add element %s number " ZEND_LONG_FMT " when only 0 such elements exist", mynode->name, Z_LVAL_P(member));
if (member && Z_LVAL_P(member) != 0) {
node = NULL;
appendable = false;
}
} else if (member) {
node = sxe_get_element_by_offset(sxe, Z_LVAL_P(member), node, &cnt);
Expand All @@ -319,11 +321,13 @@ static zval *sxe_prop_dim_read(zend_object *object, zval *member, bool elements,
if (node) {
node_as_zval(sxe, node, rv, SXE_ITER_NONE, NULL, sxe->iter.nsprefix, sxe->iter.isprefix);
} else if (type == BP_VAR_W || type == BP_VAR_RW) {
if (member && cnt < Z_LVAL_P(member)) {
if (member && (Z_LVAL_P(member) < 0 || cnt < Z_LVAL_P(member))) {
php_error_docref(NULL, E_WARNING, "Cannot add element %s number " ZEND_LONG_FMT " when only " ZEND_LONG_FMT " such elements exist", mynode->name, Z_LVAL_P(member), cnt);
}
node = xmlNewTextChild(mynode->parent, mynode->ns, mynode->name, NULL);
node_as_zval(sxe, node, rv, SXE_ITER_NONE, NULL, sxe->iter.nsprefix, sxe->iter.isprefix);
if (appendable && (!member || Z_LVAL_P(member) >= 0)) {
node = xmlNewTextChild(mynode->parent, mynode->ns, mynode->name, NULL);
node_as_zval(sxe, node, rv, SXE_ITER_NONE, NULL, sxe->iter.nsprefix, sxe->iter.isprefix);
}
}
} else {
/* In BP_VAR_IS mode only return a proper node if it actually exists. */
Expand Down Expand Up @@ -527,19 +531,18 @@ static zval *sxe_prop_dim_write(zend_object *object, zval *member, zval *value,
if (!member || Z_TYPE_P(member) == IS_LONG) {
if (node->type == XML_ATTRIBUTE_NODE) {
zend_throw_error(NULL, "Cannot create duplicate attribute");
if (value_str) {
zend_string_release(value_str);
}
return &EG(error_zval);
value = &EG(error_zval);
goto out;
}

if (sxe->iter.type == SXE_ITER_NONE) {
newnode = node;
++counter;
if (member && Z_LVAL_P(member) > 0) {
if (member && Z_LVAL_P(member) != 0) {
php_error_docref(NULL, E_WARNING, "Cannot add element %s number " ZEND_LONG_FMT " when only 0 such elements exist", mynode->name, Z_LVAL_P(member));
value = &EG(error_zval);
goto out;
}
newnode = node;
++counter;
} else if (member) {
newnode = sxe_get_element_by_offset(sxe, Z_LVAL_P(member), node, &cnt);
if (newnode) {
Expand Down Expand Up @@ -586,10 +589,14 @@ static zval *sxe_prop_dim_write(zend_object *object, zval *member, zval *value,
newnode = xmlNewTextChild(mynode, NULL, (xmlChar *)Z_STRVAL_P(member), value_str ? (xmlChar *)ZSTR_VAL(value_str) : NULL);
}
} else if (!member || Z_TYPE_P(member) == IS_LONG) {
if (member && cnt < Z_LVAL_P(member)) {
if (member && (Z_LVAL_P(member) < 0 || cnt < Z_LVAL_P(member))) {
php_error_docref(NULL, E_WARNING, "Cannot add element %s number " ZEND_LONG_FMT " when only " ZEND_LONG_FMT " such elements exist", mynode->name, Z_LVAL_P(member), cnt);
}
newnode = xmlNewTextChild(mynode->parent, mynode->ns, mynode->name, value_str ? (xmlChar *)ZSTR_VAL(value_str) : NULL);
if (member && Z_LVAL_P(member) < 0) {
value = &EG(error_zval);
} else {
newnode = xmlNewTextChild(mynode->parent, mynode->ns, mynode->name, value_str ? (xmlChar *)ZSTR_VAL(value_str) : NULL);
}
}
} else if (attribs) {
if (Z_TYPE_P(member) == IS_LONG) {
Expand All @@ -600,6 +607,7 @@ static zval *sxe_prop_dim_write(zend_object *object, zval *member, zval *value,
}
}

out:
if (member == &tmp_zv) {
zval_ptr_dtor_str(&tmp_zv);
}
Expand Down
94 changes: 94 additions & 0 deletions ext/simplexml/tests/sxe_int_offset_no_alias.phpt
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,94 @@
--TEST--
Integer offsets that cannot resolve must never alias or mutate a node
--EXTENSIONS--
simplexml
--FILE--
<?php
function fresh(): SimpleXMLElement {
return simplexml_load_string('<r a="1" b="2"><item>a</item><item>b</item><item>c</item></r>');
}

function state(SimpleXMLElement $x): string {
return trim(strstr($x->asXML(), '<r'));
}

echo "== element list ==\n";
$x = fresh();
var_dump(isset($x->item[-1]));
var_dump($x->item[-1]);
var_dump((string) $x->item[0]);
$x->item[-1] = 'Z';
echo state($x), "\n";
unset($x->item[-1]);
echo state($x), "\n";
$x->item[5] = 'P';
echo state($x), "\n";

echo "== single element ==\n";
$x = fresh();
$n = $x->item[0];
var_dump(isset($n[-1]));
var_dump($n[-1]);
var_dump($n[5]);
$n[-1] = 'Z';
echo state($x), "\n";
$n[5] = 'Y';
echo state($x), "\n";
unset($n[-1]);
echo state($x), "\n";
var_dump((string) $n[0]);

echo "== nested write ==\n";
$x = fresh();
try {
$x->item[-1]->kid = 'K';
} catch (Throwable $e) {
echo $e::class, ': ', $e->getMessage(), "\n";
}
echo state($x), "\n";

echo "== attributes ==\n";
$x = fresh();
$at = $x->attributes();
var_dump(isset($at[-1]));
var_dump($at[-1]);
$at[-1] = 'z';
echo state($x), "\n";
?>
--EXPECTF--
== element list ==
bool(false)
NULL
string(1) "a"

Warning: main(): Cannot add element item number -1 when only 3 such elements exist in %s on line %d
<r a="1" b="2"><item>a</item><item>b</item><item>c</item></r>
<r a="1" b="2"><item>a</item><item>b</item><item>c</item></r>

Warning: main(): Cannot add element item number 5 when only 3 such elements exist in %s on line %d
<r a="1" b="2"><item>a</item><item>b</item><item>c</item><item>P</item></r>
== single element ==
bool(false)
NULL
NULL

Warning: main(): Cannot add element item number -1 when only 0 such elements exist in %s on line %d
<r a="1" b="2"><item>a</item><item>b</item><item>c</item></r>

Warning: main(): Cannot add element item number 5 when only 0 such elements exist in %s on line %d
<r a="1" b="2"><item>a</item><item>b</item><item>c</item></r>
<r a="1" b="2"><item>a</item><item>b</item><item>c</item></r>
string(1) "a"
== nested write ==

Warning: main(): Cannot add element item number -1 when only 3 such elements exist in %s on line %d

Notice: Indirect modification of overloaded element of SimpleXMLElement has no effect in %s on line %d
Error: Attempt to assign property "kid" on null
<r a="1" b="2"><item>a</item><item>b</item><item>c</item></r>
== attributes ==
bool(false)
NULL

Warning: main(): Cannot change attribute number -1 when only 0 attributes exist in %s on line %d
<r a="1" b="2"><item>a</item><item>b</item><item>c</item></r>
Loading