[php-src] Issue #7737: openssl_seal()/_open() is not able to handle gcm cipers, e.g. aes-256-gcm

Issue: https://github.com/php/php-src/issues/7737 Author: rotdrop ### Description The following code: ```php <?php const NUM_KEYS = 2; for ($i = 0; $i < NUM_KEYS; $i++) { $keys[] = $key = openssl_pkey_new(); $details = openssl_pkey_get_details($key); $pubKeys[] = $details['key']; $privKeys[] = openssl_pkey_get_private($key); } $data = 'Test Data String'; $ciphers = [ 'aes-256-ctr', 'aes-256-gcm', ]; foreach ($ciphers as $cipherAlgo) { echo "*** TESTING $cipherAlgo ***" . PHP_EOL . PHP_EOL; $iv = \random_bytes(openssl_cipher_iv_length($cipherAlgo)); $result = openssl_seal($data, $sealedData, $sealedKeys, $pubKeys, $cipherAlgo, $iv); echo "DATA : " . strlen($data) . ' ' . $data . PHP_EOL; echo "IV-LEN: " . openssl_cipher_iv_length($cipherAlgo) . PHP_EOL; echo "IV : " . bin2hex($iv) . PHP_EOL; echo "ENC DATA: " . strlen($sealedData) . ' ' . bin2hex($sealedData) . PHP_EOL; echo "RESULT: " . ($result ? 'true' : 'false') . PHP_EOL; echo PHP_EOL; // Try decrypt foreach ($keys as $i => $key) { $decrypted = null; // ;) $result = openssl_open($sealedData, $decrypted, $sealedKeys[$i], $key, $cipherAlgo, $iv); echo "OPEN: " . $decrypted . PHP_EOL; echo "RESULT: " . ($result ? 'true' : 'false') . PHP_EOL; $result = openssl_private_decrypt($sealedKeys[$i], $unsealedKey, $key); echo "UNSEAL: " . bin2hex($unsealedKey) . PHP_EOL; echo "RESULT: " . ($result ? 'true' : 'false') . PHP_EOL; echo "DECRYPT: " . openssl_decrypt($sealedData, $cipherAlgo, $unsealedKey, OPENSSL_RAW_DATA, $iv) . PHP_EOL; } echo PHP_EOL; } ``` Resulted in this output: ``` $ ./openssl-seal-test.php *** TESTING aes-256-ctr *** DATA : 16 Test Data String IV-LEN: 16 IV : 37ff67041864b987b8ec2dcd0879f55e ENC DATA: 16 2a748aa6ae176caf59cf22868304d65a RESULT: true OPEN: Test Data String RESULT: true UNSEAL: 8745e00bdf3d88bd1caa8ec0150a9b369eade92e57fc2d26ae283f224c66af14 RESULT: true DECRYPT: Test Data String OPEN: Test Data String RESULT: true UNSEAL: 8745e00bdf3d88bd1caa8ec0150a9b369eade92e57fc2d26ae283f224c66af14 RESULT: true DECRYPT: Test Data String *** TESTING aes-256-gcm *** DATA : 16 Test Data String IV-LEN: 12 IV : 033b1589f62bebbfffa3adda ENC DATA: 16 a531f88fc51e373235c928cae1eb7c29 RESULT: true OPEN: RESULT: false UNSEAL: 600cf6e76cf4ae9d48a881e0649af4682aa9065e63bec515a6b8c9678e398d36 RESULT: true DECRYPT: OPEN: RESULT: false UNSEAL: 600cf6e76cf4ae9d48a881e0649af4682aa9065e63bec515a6b8c9678e398d36 RESULT: true DECRYPT: ``` But I expected this output instead: ``` [...] *** TESTING aes-256-gcm *** DATA : 16 Test Data String IV-LEN: 12 IV : 033b1589f62bebbfffa3adda ENC DATA: 16 a531f88fc51e373235c928cae1eb7c29 RESULT: true OPEN: Test Data String RESULT: true UNSEAL: 600cf6e76cf4ae9d48a881e0649af4682aa9065e63bec515a6b8c9678e398d36 RESULT: false DECRYPT: OPEN: Test Data String RESULT: true UNSEAL: 600cf6e76cf4ae9d48a881e0649af4682aa9065e63bec515a6b8c9678e398d36 RESULT: false DECRYPT: ``` The point is that the gcm-cipher need the authentication tag for decrypting the data. This however does not seem to be saved by the openssl_seal() function. I have also placed a question in the OpenSSL issue tracker: https://github.com/openssl/openssl/issues/17235 ### PHP Version PHP 8.0.13 (cli) (built: Nov 27 2021 17:17:19) ( ZTS ) ### Operating System Gentoo Linux 5.15.6, but should not matter