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Fix GH-21986: PharData::getContent() crash on infinite recursion with… #21989

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Fix GH-21986: PharData::getContent() crash on infinite recursion with… #21989

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Fix GH-21986: PharData::getContent() crash on infinite recursion with…
devnexen May 8, 2026
d852b2f
add test
devnexen May 8, 2026
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43 changes: 43 additions & 0 deletions ext/phar/tests/tar/gh21986.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,43 @@
--TEST--
GH-21986 (PharData::getContent() crash on circular symlink chain in tar)
--EXTENSIONS--
phar
--FILE--
<?php
function tar_symlink($name, $target) {
$h = str_pad($name, 100, "\0");
$h .= "0000777\0";
$h .= "0000000\0";
$h .= "0000000\0";
$h .= "00000000000\0";
$h .= "00000000000\0";
$h .= str_repeat(' ', 8);
$h .= '2';
$h .= str_pad($target, 100, "\0");
$h .= "ustar\0" . "00";
$h = str_pad($h, 512, "\0");

$sum = 0;
for ($i = 0; $i < 512; $i++) {
$sum += ord($h[$i]);
}
return substr_replace($h, sprintf("%06o\0 ", $sum), 148, 8);
}

$tar = __DIR__ . '/gh21986.tar';
file_put_contents(
$tar,
tar_symlink('a.txt', 'b.txt') .
tar_symlink('b.txt', 'a.txt') .
str_repeat("\0", 1024)
);

$phar = new PharData($tar);
var_dump($phar['a.txt']->getContent());
?>
--CLEAN--
<?php
@unlink(__DIR__ . '/gh21986.tar');
?>
--EXPECT--
string(0) ""
30 changes: 20 additions & 10 deletions ext/phar/util.c
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Original file line number Diff line number Diff line change
Expand Up @@ -64,24 +64,34 @@ phar_entry_info *phar_get_link_source(phar_entry_info *entry) /* {{{ */
{
phar_entry_info *link_entry;
char *link;
uint32_t depth = 0, max_depth;

if (!entry->link) {
return entry;
}

link = phar_get_link_location(entry);
if (NULL != (link_entry = zend_hash_str_find_ptr(&(entry->phar->manifest), entry->link, strlen(entry->link))) ||
NULL != (link_entry = zend_hash_str_find_ptr(&(entry->phar->manifest), link, strlen(link)))) {
if (link != entry->link) {
efree(link);
max_depth = zend_hash_num_elements(&(entry->phar->manifest));

while (entry->link) {
if (UNEXPECTED(++depth > max_depth)) {
return NULL;
}
return phar_get_link_source(link_entry);
} else {
if (link != entry->link) {
efree(link);
link = phar_get_link_location(entry);

if (NULL != (link_entry = zend_hash_str_find_ptr(&(entry->phar->manifest), entry->link, strlen(entry->link))) ||
NULL != (link_entry = zend_hash_str_find_ptr(&(entry->phar->manifest), link, strlen(link)))) {
if (link != entry->link) {
efree(link);
}
entry = link_entry;
} else {
if (link != entry->link) {
efree(link);
}
return NULL;
}
return NULL;
}
return entry;
}
/* }}} */

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