bisakhmondal commented on a change in pull request #5594: URL: https://github.com/apache/apisix/pull/5594#discussion_r758913144
########## File path: apisix/plugins/aws-lambda.lua ########## @@ -0,0 +1,183 @@ +-- +-- Licensed to the Apache Software Foundation (ASF) under one or more +-- contributor license agreements. See the NOTICE file distributed with +-- this work for additional information regarding copyright ownership. +-- The ASF licenses this file to You under the Apache License, Version 2.0 +-- (the "License"); you may not use this file except in compliance with +-- the License. You may obtain a copy of the License at +-- +-- http://www.apache.org/licenses/LICENSE-2.0 +-- +-- Unless required by applicable law or agreed to in writing, software +-- distributed under the License is distributed on an "AS IS" BASIS, +-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +-- See the License for the specific language governing permissions and +-- limitations under the License. + +local ngx = ngx +local hmac = require("resty.hmac") +local hex_encode = require("resty.string").to_hex +local resty_sha256 = require("resty.sha256") +local str_strip = require("pl.stringx").strip +local norm_path = require("pl.path").normpath +local pairs = pairs +local tab_concat = table.concat +local tab_sort = table.sort +local os = os + + +local plugin_name = "aws-lambda" +local plugin_version = 0.1 +local priority = -1899 + +local ALGO = "AWS4-HMAC-SHA256" + +local function hmac256(key, msg) + return hmac:new(key, hmac.ALGOS.SHA256):final(msg) +end + +local function sha256(msg) + local hash = resty_sha256:new() + hash:update(msg) + local digest = hash:final() + return hex_encode(digest) +end + +local function get_signature_key(key, datestamp, region, service) + local kDate = hmac256("AWS4" .. key, datestamp) + local kRegion = hmac256(kDate, region) + local kService = hmac256(kRegion, service) + local kSigning = hmac256(kService, "aws4_request") + return kSigning +end + +local aws_authz_schema = { + type = "object", + properties = { + -- API Key based authorization + apikey = {type = "string"}, + -- IAM role based authorization, works via aws v4 request signing + -- more at https://docs.aws.amazon.com/general/latest/gr/sigv4_signing.html + iam = { + type = "object", + properties = { + accesskey = { + type = "string", + description = "access key id from from aws iam console" + }, + secretkey = { + type = "string", + description = "secret access key from from aws iam console" + }, + aws_region = { + type = "string", + default = "us-east-1", + description = "the aws region that is receiving the request" + }, + service = { + type = "string", + default = "execute-api", + description = "the service that is receiving the request" + } + }, + required = {"accesskey", "secretkey"} + } + } +} + +local function request_processor(conf, ctx, params) + local headers = params.headers + -- set authorization headers if not already set by the client + -- we are following not to overwrite the authz keys + if not headers["x-api-key"] then + if conf.authorization and conf.authorization.apikey then + headers["x-api-key"] = conf.authorization.apikey + return + end + end + + -- performing aws v4 request signing for IAM authorization + -- visit https://docs.aws.amazon.com/general/latest/gr/sigv4-signed-request-examples.html + -- to look at the pseudocode in python. + if headers["authorization"] or not conf.authorization or not conf.authorization.iam then + return + end + + -- create a date for headers and the credential string + local t = ngx.time() + local amzdate = os.date("!%Y%m%dT%H%M%SZ", t) + local datestamp = os.date("!%Y%m%d", t) -- Date w/o time, used in credential scope + headers["X-Amz-Date"] = amzdate + + -- computing canonical uri + local canonical_uri = norm_path(params.path) + if canonical_uri ~= "/" then + if canonical_uri:sub(-1, -1) == "/" then + canonical_uri = canonical_uri:sub(1, -2) + end + if canonical_uri:sub(1, 1) ~= "/" then + canonical_uri = "/" .. canonical_uri + end + end + + -- computing canonical query string + local canonical_qs = {} + for k, v in pairs(params.query) do + canonical_qs[#canonical_qs+1] = ngx.unescape_uri(k) .. "=" .. ngx.unescape_uri(v) + end + + tab_sort(canonical_qs) + canonical_qs = tab_concat(canonical_qs, "&") + + -- computing canonical and signed headers + + local canonical_headers, signed_headers = {}, {} + for k, v in pairs(headers) do + k = k:lower() + if k ~= "connection" then + signed_headers[#signed_headers+1] = k Review comment: First of all, I would like to specify, we are not tampering connection header for the request that is being sent to the lambda. This section performs aws v4 request signing with aws iam secret key. As per the aws docs, to have the authenticity of the request (and to validate that the request has not been modified by any third party over the wire) it suggests generating hash digest from as many headers as we can (however `host` and `x-amz-date` is mandatory). In real-world testing what i have found that aws gateway doesn't include the `connection` header value (`keep-alive`, `close`) for hash calculation. That's why I simply omitted it as it never was any hard requirement.  -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: notifications-unsubscr...@apisix.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
