Refactor the encryption process to extract encrypt/decrypt functions (#176)

Refactor the encryption process to extract encrypt/decrypt functions

1 files changed, 2 insertions, 121 deletions

diff --git a/src/sp_cookie_encryption.c b/src/sp_cookie_encryption.c
index 4ecb97d..9030112 100644
--- a/src/sp_cookie_encryption.c
+++ b/src/sp_cookie_encryption.c
@@ -4,42 +4,6 @@
 
 ZEND_DECLARE_MODULE_GLOBALS(snuffleupagus)
 
-static zend_long nonce_d = 0;
-
-static inline void generate_key(unsigned char *key) {
-  PHP_SHA256_CTX ctx;
-  const char *user_agent = getenv("HTTP_USER_AGENT");
-  const char *env_var =
-      getenv(SNUFFLEUPAGUS_G(config).config_snuffleupagus->cookies_env_var);
-  const char *encryption_key =
-      SNUFFLEUPAGUS_G(config).config_snuffleupagus->encryption_key;
-
-  assert(32 == crypto_secretbox_KEYBYTES);  // 32 is the size of a SHA256.
-  assert(encryption_key);                   // Encryption key can't be NULL
-
-  PHP_SHA256Init(&ctx);
-
-  if (user_agent) {
-    PHP_SHA256Update(&ctx, (unsigned char *)user_agent, strlen(user_agent));
-  }
-
-  if (env_var) {
-    PHP_SHA256Update(&ctx, (unsigned char *)env_var, strlen(env_var));
-  } else {
-    sp_log_err("cookie_encryption",
-               "The environment variable '%s'"
-               "is empty, cookies are weakly encrypted.",
-               SNUFFLEUPAGUS_G(config).config_snuffleupagus->cookies_env_var);
-  }
-
-  if (encryption_key) {
-    PHP_SHA256Update(&ctx, (const unsigned char *)encryption_key,
-                     strlen(encryption_key));
-  }
-
-  PHP_SHA256Final((unsigned char *)key, &ctx);
-}
-
 static inline const sp_cookie *sp_lookup_cookie_config(const char *key) {
   sp_list_node *it = SNUFFLEUPAGUS_G(config).config_cookie->cookies;
 
@@ -56,9 +20,6 @@ static inline const sp_cookie *sp_lookup_cookie_config(const char *key) {
 /* called at RINIT time with each cookie, eventually decrypt said cookie */
 int decrypt_cookie(zval *pDest, int num_args, va_list args,
                    zend_hash_key *hash_key) {
-  unsigned char key[crypto_secretbox_KEYBYTES] = {0};
-  zend_string *debase64;
-  unsigned char *decrypted;
   const sp_cookie *cookie = sp_lookup_cookie_config(ZSTR_VAL(hash_key->key));
   int ret = 0;
 
@@ -72,57 +33,7 @@ int decrypt_cookie(zval *pDest, int num_args, va_list args,
     return ZEND_HASH_APPLY_KEEP;
   }
 
-  debase64 = php_base64_decode((unsigned char *)(Z_STRVAL_P(pDest)),
-                               Z_STRLEN_P(pDest));
-
-  if (ZSTR_LEN(debase64) <
-      crypto_secretbox_NONCEBYTES + crypto_secretbox_ZEROBYTES) {
-    if (true == cookie->simulation) {
-      sp_log_msg(
-          "cookie_encryption", SP_LOG_SIMULATION,
-          "Buffer underflow tentative detected in cookie encryption handling "
-          "for %s. Using the cookie 'as it' instead of decrypting it.",
-          ZSTR_VAL(hash_key->key));
-      return ZEND_HASH_APPLY_KEEP;
-    } else {
-      sp_log_msg(
-          "cookie_encryption", SP_LOG_DROP,
-          "Buffer underflow tentative detected in cookie encryption handling.");
-      return ZEND_HASH_APPLY_REMOVE;
-    }
-  }
-
-  generate_key(key);
-
-  decrypted = ecalloc(ZSTR_LEN(debase64), 1);
-
-  ret = crypto_secretbox_open(
-      decrypted,
-      (unsigned char *)(ZSTR_VAL(debase64) + crypto_secretbox_NONCEBYTES),
-      ZSTR_LEN(debase64) - crypto_secretbox_NONCEBYTES,
-      (unsigned char *)ZSTR_VAL(debase64), key);
-
-  if (-1 == ret) {
-    if (true == cookie->simulation) {
-      sp_log_msg(
-          "cookie_encryption", SP_LOG_SIMULATION,
-          "Something went wrong with the decryption of %s. Using the cookie "
-          "'as it' instead of decrypting it",
-          ZSTR_VAL(hash_key->key));
-      return ZEND_HASH_APPLY_KEEP;
-    } else {
-      sp_log_msg("cookie_encryption", SP_LOG_DROP,
-                 "Something went wrong with the decryption of %s.",
-                 ZSTR_VAL(hash_key->key));
-      return ZEND_HASH_APPLY_REMOVE;
-    }
-  }
-
-  ZVAL_STRINGL(pDest, (char *)(decrypted + crypto_secretbox_ZEROBYTES),
-               ZSTR_LEN(debase64) - crypto_secretbox_NONCEBYTES - 1 -
-                   crypto_secretbox_ZEROBYTES);
-
-  return ZEND_HASH_APPLY_KEEP;
+  return decrypt_zval(pDest, cookie->simulation, hash_key);
 }
 
 /*
@@ -131,37 +42,7 @@ int decrypt_cookie(zval *pDest, int num_args, va_list args,
 ** operation).
 */
 static zend_string *encrypt_data(char *data, unsigned long long data_len) {
-  const size_t encrypted_msg_len = crypto_secretbox_ZEROBYTES + data_len + 1;
-  const size_t emsg_and_nonce_len =
-      encrypted_msg_len + crypto_secretbox_NONCEBYTES;
-
-  unsigned char key[crypto_secretbox_KEYBYTES] = {0};
-  unsigned char nonce[crypto_secretbox_NONCEBYTES] = {0};
-  unsigned char *data_to_encrypt = ecalloc(encrypted_msg_len, 1);
-  unsigned char *encrypted_data = ecalloc(emsg_and_nonce_len, 1);
-
-  generate_key(key);
-
-  /* tweetnacl's API requires the message to be padded with
-  crypto_secretbox_ZEROBYTES zeroes. */
-  memcpy(data_to_encrypt + crypto_secretbox_ZEROBYTES, data, data_len);
-
-  assert(sizeof(zend_long) <= crypto_secretbox_NONCEBYTES);
-
-  if (0 == nonce_d) {
-    /* A zend_long should be enough to avoid collisions */
-    if (php_random_int_throw(0, ZEND_LONG_MAX, &nonce_d) == FAILURE) {
-      return NULL;  // LCOV_EXCL_LINE
-    }
-  }
-  nonce_d++;
-  sscanf((char *)nonce, "%ld", &nonce_d);
-
-  memcpy(encrypted_data, nonce, crypto_secretbox_NONCEBYTES);
-  crypto_secretbox(encrypted_data + crypto_secretbox_NONCEBYTES,
-                   data_to_encrypt, encrypted_msg_len, nonce, key);
-
-  zend_string *z = php_base64_encode(encrypted_data, emsg_and_nonce_len);
+  zend_string *z = encrypt_zval(data, data_len);
   sp_log_debug("cookie_encryption", "Cookie value:%s:", z->val);
   return z;
 }