chore(utils): better caching of crypto primitives and move to non-deprecated crypto

Author: bungle

Changes.md

@@ -14,6 +14,7 @@ All notable changes to `lua-resty-session` will be documented in this file.
 ### Changed
 - chore(utils): safer utils.is_fips_mode (fix #176)
 - chore(session): a bit more relaxed assertions (fix #175)
+- chore(utils): better caching of crypto primitives and move to non-deprecated crypto
 
 
 ## [4.0.5] - 2023-08-16

lib/resty/session/utils.lua

@@ -480,34 +480,56 @@ end
 
 
 local derive_hkdf_sha256 do
-  local kdf_derive
+  local kdf
+  local hkdf_extract
+  local hkdf_expand
 
   local EXTRACTED_KEYS = {}
 
   local HKDF_SHA256_EXTRACT_OPTS
   local HKDF_SHA256_EXPAND_OPTS
 
   local function derive_hkdf_sha256_real(ikm, nonce, usage, size)
-    local err
-    local key = EXTRACTED_KEYS[ikm]
+    local key, err, _ = EXTRACTED_KEYS[ikm]
     if not key then
-      HKDF_SHA256_EXTRACT_OPTS.hkdf_key = ikm
-      key, err = kdf_derive(HKDF_SHA256_EXTRACT_OPTS)
-      HKDF_SHA256_EXTRACT_OPTS.hkdf_key = ""
+      if not hkdf_extract then
+        hkdf_extract, err = kdf.new("HKDF")
+        if not hkdf_extract then
+          return nil, err
+        end
+      end
+
+      HKDF_SHA256_EXTRACT_OPTS.key = ikm
+      key, err = hkdf_extract:derive(32, HKDF_SHA256_EXTRACT_OPTS)
+      HKDF_SHA256_EXTRACT_OPTS.key = ""
       if not key then
+        hkdf_extract = nil
         return nil, err
       end
       EXTRACTED_KEYS[ikm] = key
     end
 
-    HKDF_SHA256_EXPAND_OPTS.hkdf_key = key
-    HKDF_SHA256_EXPAND_OPTS.hkdf_info = usage .. ":" .. nonce
-    HKDF_SHA256_EXPAND_OPTS.outlen = size
-    key, err = kdf_derive(HKDF_SHA256_EXPAND_OPTS)
+    if not hkdf_expand then
+      hkdf_expand, err = kdf.new("HKDF")
+      if not hkdf_expand then
+        return nil, err
+      end
+    end
+
+    HKDF_SHA256_EXPAND_OPTS.key = key
+    HKDF_SHA256_EXPAND_OPTS.info = usage .. ":" .. nonce
+
+    key, err = hkdf_expand:derive(size or 44, HKDF_SHA256_EXPAND_OPTS)
     if not key then
+      hkdf_expand = nil
       return nil, err
     end
 
+    _, err = hkdf_expand:reset()
+    if err then
+      hkdf_expand = nil
+    end
+
     return key
   end
 
@@ -528,27 +550,22 @@ local derive_hkdf_sha256 do
   -- local nonce = utils.rand_bytes(32)
   -- local key, err = utils.derive_hkdf_sha256(ikm, nonce, "encryption", 32)
   derive_hkdf_sha256 = function(ikm, nonce, usage, size)
-    if not kdf_derive then
-      local kdf = require("resty.openssl.kdf")
+    if not kdf then
+      kdf = require("resty.openssl.kdf")
       HKDF_SHA256_EXTRACT_OPTS = {
-        type = kdf.HKDF,
-        outlen = 32,
-        md = "sha256",
+        digest = "sha256",
+        mode = kdf.HKDEF_MODE_EXTRACT_ONLY,
+        key = "",
         salt = "",
-        hkdf_key = "",
-        hkdf_mode = kdf.HKDEF_MODE_EXTRACT_ONLY,
-        hkdf_info = "",
+        info = "",
       }
       HKDF_SHA256_EXPAND_OPTS = {
-        type = kdf.HKDF,
-        outlen = 44,
-        md = "sha256",
+        digest = "sha256",
+        mode = kdf.HKDEF_MODE_EXPAND_ONLY,
+        key = "",
         salt = "",
-        hkdf_key = "",
-        hkdf_mode = kdf.HKDEF_MODE_EXPAND_ONLY,
-        hkdf_info = "",
+        info = "",
       }
-      kdf_derive = kdf.derive
     end
     derive_hkdf_sha256 = derive_hkdf_sha256_real
     return derive_hkdf_sha256(ikm, nonce, usage, size)
@@ -557,20 +574,35 @@ end
 
 
 local derive_pbkdf2_hmac_sha256 do
-  local kdf_derive
+  local kdf
+  local pbkdf2
 
   local PBKDF2_SHA256_OPTS
 
   local function derive_pbkdf2_hmac_sha256_real(pass, salt, usage, size, iterations)
-    PBKDF2_SHA256_OPTS.pass = pass
+    local _, err, key
+    if not pbkdf2 then
+      pbkdf2, err = kdf.new("PBKDF2")
+      if err then
+        return nil, err
+      end
+    end
+
+    PBKDF2_SHA256_OPTS.iter = iterations or 10000
     PBKDF2_SHA256_OPTS.salt = usage .. ":" .. salt
-    PBKDF2_SHA256_OPTS.outlen = size
-    PBKDF2_SHA256_OPTS.pbkdf2_iter = iterations
-    local key, err = kdf_derive(PBKDF2_SHA256_OPTS)
+    PBKDF2_SHA256_OPTS.pass = pass
+
+    key, err = pbkdf2:derive(size or 44, PBKDF2_SHA256_OPTS)
     if not key then
+      pbkdf2 = nil
       return nil, err
     end
 
+    _, err = pbkdf2:reset()
+    if err then
+      pbkdf2 = nil
+    end
+
     return key
   end
 
@@ -592,17 +624,14 @@ local derive_pbkdf2_hmac_sha256 do
   -- local salt = utils.rand_bytes(32)
   -- local key, err = utils.derive_pbkdf2_hmac_sha256(pass, salt, "encryption", 32, 10000)
   derive_pbkdf2_hmac_sha256 = function(pass, salt, usage, size, iterations)
-    if not kdf_derive then
-      local kdf = require("resty.openssl.kdf")
+    if not kdf then
+      kdf = require("resty.openssl.kdf")
       PBKDF2_SHA256_OPTS = {
-        type = kdf.PBKDF2,
-        outlen = 44,
-        md = "sha256",
-        pass = "",
+        digest = "sha256",
+        iter = 10000,
         salt = "",
-        pbkdf2_iter = 10000,
+        pass = "",
       }
-      kdf_derive = kdf.derive
     end
     derive_pbkdf2_hmac_sha256 = derive_pbkdf2_hmac_sha256_real
     return derive_pbkdf2_hmac_sha256(pass, salt, usage, size, iterations)
@@ -690,26 +719,44 @@ end
 
 
 local encrypt_aes_256_gcm, decrypt_aes_256_gcm do
+  local cipher
+  local cipher_encrypt
+  local cipher_decrypt
+
   local AES_256_GCP_CIPHER = "aes-256-gcm"
   local AES_256_GCM_TAG_SIZE = 16
 
-  local cipher_aes_256_gcm
   local function encrypt_aes_256_gcm_real(key, iv, plaintext, aad)
-    local ciphertext, err = cipher_aes_256_gcm:encrypt(key, iv, plaintext, false, aad)
+    if not cipher_encrypt then
+      cipher_encrypt = cipher.new(AES_256_GCP_CIPHER)
+    end
+
+    local ciphertext, err = cipher_encrypt:encrypt(key, iv, plaintext, false, aad)
     if not ciphertext then
+      cipher_encrypt = nil
       return nil, err
     end
 
-    local tag, err = cipher_aes_256_gcm:get_aead_tag(AES_256_GCM_TAG_SIZE)
+    local tag, err = cipher_encrypt:get_aead_tag(AES_256_GCM_TAG_SIZE)
     if not tag then
+      cipher_encrypt = nil
       return nil, err
     end
 
     return ciphertext, nil, tag
   end
 
   local function decrypt_aes_256_gcm_real(key, iv, ciphertext, aad, tag)
-    return cipher_aes_256_gcm:decrypt(key, iv, ciphertext, false, aad, tag)
+    if not cipher_decrypt then
+      cipher_decrypt = cipher.new(AES_256_GCP_CIPHER)
+    end
+
+    local plaintext, err = cipher_decrypt:decrypt(key, iv, ciphertext, false, aad, tag)
+    if not plaintext then
+      cipher_decrypt = nil
+    end
+
+    return plaintext, err
   end
 
   ---
@@ -731,8 +778,8 @@ local encrypt_aes_256_gcm, decrypt_aes_256_gcm do
   -- local key, err, iv = utils.derive_aes_gcm_256_key_and_iv(ikm, nonce)
   -- local enc, err, tag = utils.encrypt_aes_256_gcm(key, iv, "hello", "[email protected]")
   encrypt_aes_256_gcm = function(key, iv, plaintext, aad)
-    if not cipher_aes_256_gcm then
-      cipher_aes_256_gcm = require("resty.openssl.cipher").new(AES_256_GCP_CIPHER)
+    if not cipher then
+      cipher = require("resty.openssl.cipher")
     end
     encrypt_aes_256_gcm = encrypt_aes_256_gcm_real
     return encrypt_aes_256_gcm(key, iv, plaintext, aad)
@@ -744,10 +791,10 @@ local encrypt_aes_256_gcm, decrypt_aes_256_gcm do
   -- @function utils.decrypt_aes_256_gcm
   -- @tparam string key encryption key
   -- @tparam string iv initialization vector
-  -- @tparam string plaintext plain text
+  -- @tparam string ciphertext plain text
   -- @tparam string aad additional authenticated data
   -- @tparam string tag authentication tag
-  -- @treturn string|nil ciphertext
+  -- @treturn string|nil plaintext
   -- @treturn string|nil error message
   --
   -- @usage
@@ -758,8 +805,8 @@ local encrypt_aes_256_gcm, decrypt_aes_256_gcm do
   -- local enc, err, tag = utils.encrypt_aes_256_gcm(key, iv, "hello", "[email protected]")
   -- local out, err = utils.decrypt_aes_256_gcm(key, iv, ciphertext, "[email protected]", tag)
   decrypt_aes_256_gcm = function(key, iv, ciphertext, aad, tag)
-    if not cipher_aes_256_gcm then
-      cipher_aes_256_gcm = require("resty.openssl.cipher").new(AES_256_GCP_CIPHER)
+    if not cipher then
+      cipher = require("resty.openssl.cipher")
     end
     decrypt_aes_256_gcm = decrypt_aes_256_gcm_real
     return decrypt_aes_256_gcm(key, iv, ciphertext, aad, tag)
@@ -768,21 +815,31 @@ end
 
 
 local hmac_sha256 do
+  local mac
   local hmac
-  local HMAC_SHA256_DIGEST = "sha256"
+  local MAC_MAC = "HMAC"
+  local MAC_DIGEST = "sha256"
 
   local function hmac_sha256_real(key, value)
-    local mac, err = hmac.new(key, HMAC_SHA256_DIGEST)
-    if not mac then
-      return nil, err
+    local _, err, output
+    if not hmac then
+      hmac, err = mac.new(key, MAC_MAC, nil, MAC_DIGEST)
+      if err then
+        return nil, err
+      end
     end
 
-    local digest, err = mac:final(value)
-    if not digest then
+    output, err = hmac:final(value)
+    if not output then
       return nil, err
     end
 
-    return digest
+    _, err = hmac:reset()
+    if err then
+      hmac = nil
+    end
+
+    return output
   end
 
   ---
@@ -801,8 +858,8 @@ local hmac_sha256 do
   -- local key, err = utils.derive_hmac_sha256_key(ikm, nonce)
   -- local mac, err = utils.hmac_sha256(key, "hello")
   hmac_sha256 = function(key, value)
-    if not hmac then
-      hmac = require("resty.openssl.hmac")
+    if not mac then
+      mac = require("resty.openssl.mac")
     end
     hmac_sha256 = hmac_sha256_real
     return hmac_sha256(key, value)