adding RS256 support to JWT plugin

kong/plugins/jwt/daos.lua

@@ -8,7 +8,8 @@ local SCHEMA = {
     created_at = {type = "timestamp", immutable = true, dao_insert_value = true},
     consumer_id = {type = "id", required = true, foreign = "consumers:id"},
     key = {type = "string", unique = true, default = utils.random_string},
-    secret = {type = "string", unique = true, default = utils.random_string}
+    secret = {type = "string", unique = true, default = utils.random_string},
+    algorithm = {type = "string", enum = {"HS256", "RS256"}, default = 'HS256'}
   },
   marshall_event = function(self, t)
     return {id = t.id, consumer_id = t.consumer_id, key = t.key}

kong/plugins/jwt/handler.lua

@@ -87,6 +87,11 @@ function JwtHandler:access(conf)
     return responses.send_HTTP_FORBIDDEN("No credentials found for given '"..conf.key_claim_name.."'")
   end
 
+  -- Verify "alg"
+  if jwt.header.alg ~= jwt_secret.algorithm then
+    return responses.send_HTTP_FORBIDDEN("Invalid algorithm")
+  end
+
   local jwt_secret_value = jwt_secret.secret
   if conf.secret_is_base64 then
     jwt_secret_value = jwt:b64_decode(jwt_secret_value)

kong/plugins/jwt/jwt_parser.lua

@@ -18,19 +18,21 @@ local string_rep = string.rep
 local setmetatable = setmetatable
 
 --- Supported algorithms for signing tokens.
--- Only support HS256 for our use case.
 local alg_sign = {
-  ["HS256"] = function(data, key) return crypto.hmac.digest("sha256", data, key, true) end
+  ["HS256"] = function(data, key) return crypto.hmac.digest("sha256", data, key, true) end,
   --["HS384"] = function(data, key) return crypto.hmac.digest("sha384", data, key, true) end,
   --["HS512"] = function(data, key) return crypto.hmac.digest("sha512", data, key, true) end
+  ["RS256"] = function(data, key) return crypto.sign('sha256', data, crypto.pkey.from_pem(key, true)) end
 }
 
 --- Supported algorithms for verifying tokens.
--- Only support HS256 for our use case.
 local alg_verify = {
-  ["HS256"] = function(data, signature, key) return signature == alg_sign["HS256"](data, key) end
+  ["HS256"] = function(data, signature, key) return signature == alg_sign["HS256"](data, key) end,
   --["HS384"] = function(data, signature, key) return signature == alg_sign["HS384"](data, key) end,
   --["HS512"] = function(data, signature, key) return signature == alg_sign["HS512"](data, key) end
+  ["RS256"] = function(data, signature, key)
+    return crypto.verify('sha256', data, signature, crypto.pkey.from_pem(key))
+  end
 }
 
 --- base 64 encoding

kong/plugins/jwt/migrations/cassandra.lua

@@ -18,5 +18,14 @@ return {
     down = [[
       DROP TABLE jwt_secrets;
     ]]
+  },
+  {
+    name = "2016-03-07-jwt-auth",
+    up = [[
+      ALTER TABLE jwt_secrets ADD algorithm text;
+    ]],
+    down = [[
+      ALTER TABLE jwt_secrets DROP algorithm;
+    ]]
   }
 }

kong/plugins/jwt/migrations/postgres.lua

@@ -27,5 +27,14 @@ return {
     down = [[
       DROP TABLE jwt_secrets;
     ]]
+  },
+  {
+    name = "2016-03-07-jwt-auth",
+    up = [[
+      ALTER TABLE jwt_secrets ADD COLUMN algorithm varchar(5);
+    ]],
+    down = [[
+      ALTER TABLE jwt_secrets DROP COLUMN algorithm;
+    ]]
   }
 }

spec/plugins/jwt/access_spec.lua

@@ -86,6 +86,16 @@ describe("JWT access", function()
     assert.equal("Invalid signature", body.message)
   end)
 
+  it("should return 403 Forbidden if the alg does not match the credential", function()
+    local header = {typ = "JWT", alg = 'RS256'}
+    local jwt = jwt_encoder.encode(PAYLOAD, jwt_secret.secret, 'HS256', header)
+    local authorization = "Bearer "..jwt
+    local response, status = http_client.get(STUB_GET_URL, nil, {host = "jwt.com", authorization = authorization})
+    assert.equal(403, status)
+    local body = json.decode(response)
+    assert.equal("Invalid algorithm", body.message)
+  end)
+
   it("should proxy the request with token and consumer headers if it was verified", function()
     PAYLOAD.iss = jwt_secret.key
     local jwt = jwt_encoder.encode(PAYLOAD, jwt_secret.secret)

spec/plugins/jwt/jwt_parser_spec.lua

@@ -2,16 +2,66 @@ require "kong.tools.ngx_stub"
 
 local jwt_parser = require "kong.plugins.jwt.jwt_parser"
 
+local rs256_private_key = [[
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
+]]
+
+local rs256_public_key = [[
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAw5mp3MS3hVLkHwB9lMrE
+x34MjYCmKeH/XeMLexNpTd1FzuNv6rArovTY763CDo1Tp0xHz0LPlDJJtpqAgsnf
+DwCcgn6ddZTo1u7XYzgEDfS8J4SYdcKxZiSdVTpb9k7pByXfnwK/fwq5oeBAJXIS
+v5ZLB1IEVZHhUvGCH0udlJ2vadquR03phBHcvlNmMbJGWAetkdcKyi+7TaW7OUSj
+lge4WYERgYzBB6eJH+UfPjmw3aSPZcNXt2RckPXEbNrL8TVXYdEvwLJoJv9/I8JP
+FLiGOm5uTMEk8S4txs2efueg1XyymilCKzzuXlJvrvPA4u6HI7qNvuvkvUjQmwBH
+gwIDAQAB
+-----END PUBLIC KEY-----
+]]
+
 describe("JWT parser", function()
   describe("Encoding", function()
-    it("should properly encode", function()
+    it("should properly encode using HS256", function()
       local token = jwt_parser.encode({
         sub = "1234567890",
         name = "John Doe",
         admin = true
       }, "secret")
       assert.equal("eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJhZG1pbiI6dHJ1ZSwibmFtZSI6IkpvaG4gRG9lIiwic3ViIjoiMTIzNDU2Nzg5MCJ9.eNK_fimsCW3Q-meOXyc_dnZHubl2D4eZkIcn6llniCk", token)
     end)
+    it("should properly encode using RS256", function()
+      local token = jwt_parser.encode({
+        sub = "1234567890",
+        name = "John Doe",
+        admin = true
+      }, rs256_private_key, 'RS256')
+      assert.equal("eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJhZG1pbiI6dHJ1ZSwibmFtZSI6IkpvaG4gRG9lIiwic3ViIjoiMTIzNDU2Nzg5MCJ9.EiOLxyMimY8vbLR8EcGOlXAiEe-eEVn7Aewgu0gYIBPyiEhVTq0CzB_XtHoQ_0y4gBBBZVRnz1pgruOtNmOzcaoXnyplFm1IbrCCBKYQeA4lanmu_-Wzk6Dw4p-TimRHpf8EEHBUJSEbVEyet3cpozUo2Ep0dEfA_Nf3T-g8RjfOYXkFTr3M6FuIDq95cFZloH-DRGodUVQX508wgggtcFKN-Pi7_rWzBtQwP2u4CrFD4ZJbn2sxobzSlFb9fn4nRh_-rPPjDSeHVKwrpsYpFSLBJxwX-KhbeGUfalg2eu9tHLDPHC4gTCpoQKxxRIwfMjW5zlHOZhohKZV2ZtpcgA", token)
+    end)
   end)
   describe("Decoding", function()
     it("should throw an error if not given a string", function()
@@ -31,13 +81,20 @@ describe("JWT parser", function()
     end)
   end)
   describe("Verify signature", function()
-    it("should verify a signature", function()
+    it("should verify a signature using HS256", function()
       local token = jwt_parser.encode({sub = "foo"}, "secret")
       local jwt, err = jwt_parser:new(token)
       assert.falsy(err)
       assert.True(jwt:verify_signature("secret"))
       assert.False(jwt:verify_signature("invalid"))
     end)
+    it("should verify a signature using RS256", function()
+      local token = jwt_parser.encode({sub = "foo"}, rs256_private_key, 'RS256')
+      local jwt, err = jwt_parser:new(token)
+      assert.falsy(err)
+      assert.True(jwt:verify_signature(rs256_public_key))
+      assert.False(jwt:verify_signature(rs256_public_key:gsub('QAB', 'zzz')))
+    end)
   end)
   describe("Verify registered claims", function()
     it("should require claims passed as arguments", function()