ext/openssl: openssl_encrypt() zend mm heap overflow on AES-WRAP-PAD mode.

Fix php#22186

close phpGH-22187

Author: devnexen

NEWS

@@ -2,6 +2,9 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? ????, PHP 8.2.32
 
+- OpenSSL:
+  . Fixed bug GH-22187 (Memory corruption (zend_mm_heap corrupted) in
+    openssl_encrypt with AES-WRAP-PAD). (David Carlier)
 
 07 May 2026, PHP 8.2.31
 

ext/openssl/openssl.c

@@ -7396,6 +7396,7 @@ static int php_openssl_cipher_update(const EVP_CIPHER *cipher_type,
 		const char *aad, size_t aad_len, int enc)  /* {{{ */
 {
 	int i = 0;
+	size_t outlen = data_len + EVP_CIPHER_block_size(cipher_type);
 
 	if (mode->is_single_run_aead && !EVP_CipherUpdate(cipher_ctx, NULL, &i, NULL, (int)data_len)) {
 		php_openssl_store_errors();
@@ -7409,7 +7410,19 @@ static int php_openssl_cipher_update(const EVP_CIPHER *cipher_type,
 		return FAILURE;
 	}
 
-	*poutbuf = zend_string_alloc((int)data_len + EVP_CIPHER_block_size(cipher_type), 0);
+#ifdef EVP_CIPH_WRAP_MODE
+	if ((EVP_CIPHER_mode(cipher_type)) == EVP_CIPH_WRAP_MODE) {
+		/*
+		 * RFC 5649 wrap-with-padding rounds the input up to the block size
+		 * and prepends an integrity block, we reserve one extra block.
+		 * See EVP_EncryptUpdate(3): wrap mode may write up to
+		 * inl + cipher_block_size bytes.
+		 */
+		outlen += EVP_CIPHER_block_size(cipher_type);
+	}
+#endif
+
+	*poutbuf = zend_string_alloc(outlen, false);
 
 	if (!EVP_CipherUpdate(cipher_ctx, (unsigned char*)ZSTR_VAL(*poutbuf),
 					&i, (const unsigned char *)data, (int)data_len)) {
@@ -7421,7 +7434,7 @@ static int php_openssl_cipher_update(const EVP_CIPHER *cipher_type,
 		}
 		*/
 		php_openssl_store_errors();
-		zend_string_release_ex(*poutbuf, 0);
+		zend_string_release_ex(*poutbuf, false);
 		return FAILURE;
 	}
 

ext/openssl/tests/gh22186.phpt

@@ -0,0 +1,32 @@
+--TEST--
+GH-22186 (Heap buffer overflow in openssl_encrypt with AES-WRAP-PAD)
+--EXTENSIONS--
+openssl
+--SKIPIF--
+<?php
+/* openssl_get_cipher_methods() enumerates provider ciphers, but openssl_encrypt()
+ * resolves names via the legacy EVP_get_cipherbyname(), so on some builds the
+ * cipher is listed yet not usable. Probe the actual call path instead. */
+if (!@openssl_encrypt("test", "aes-128-wrap-pad", str_repeat("k", 16),
+        OPENSSL_RAW_DATA | OPENSSL_DONT_ZERO_PAD_KEY, str_repeat("\0", 4))) {
+    die('skip aes-128-wrap-pad not usable on this OpenSSL build');
+}
+?>
+--FILE--
+<?php
+$pass = str_repeat("k", 16);
+$iv = str_repeat("\0", 4);
+
+for ($i = 1; $i < 258; $i++) {
+    $data = str_repeat("a", $i);
+    $enc = openssl_encrypt($data, 'aes-128-wrap-pad', $pass, OPENSSL_RAW_DATA | OPENSSL_DONT_ZERO_PAD_KEY, $iv);
+    $dec = openssl_decrypt($enc, 'aes-128-wrap-pad', $pass, OPENSSL_RAW_DATA | OPENSSL_DONT_ZERO_PAD_KEY, $iv);
+    if ($dec !== $data) {
+        die("mismatch at $i\n");
+    }
+}
+
+echo "done\n";
+?>
+--EXPECT--
+done