Adds support using temporary security credentials

doc/admin-guide/plugins/s3_auth.en.rst

@@ -36,6 +36,7 @@ Using the plugin in a remap rule would be e.g.::
 
    ...  @plugin=s3_auth.so @pparam=--access_key @pparam=my-key \
                            @pparam=--secret_key @pparam=my-secret \
+                           @pparam=--session_token @pparam=my-token \
                            @pparam=--virtual_host
 
 
@@ -71,6 +72,7 @@ Configuration options::
     --version=4
 
     # Optional
+    --session_token=<token>
     --v4-include-headers=<comma-separated-list-of-headers-to-be-signed>
     --v4-exclude-headers=<comma-separated-list-of-headers-not-to-be-signed>
     --v4-region-map=region_map.config
@@ -87,6 +89,7 @@ The ``s3_auth_v4.config`` config file could look like this::
 
     access_key=<access_id>
     secret_key=<secret_key>
+    session_token=<token>
     version=4
     v4-include-headers=<comma-separated-list-of-headers-to-be-signed>
     v4-exclude-headers=<comma-separated-list-of-headers-not-to-be-signed>
@@ -141,6 +144,7 @@ This is a pretty barebone start for the S3 services, it is missing a number of f
 - It does not deal with canonicalization of AMZ headers.
 - It does not handle POST requests (but do we need to ?)
 - It does not incorporate query parameters.
+- It does not support session tokens.
 
 
 Contributions to any of these would be appreciated.

plugins/s3_auth/aws_auth_v4.h

@@ -61,6 +61,7 @@ class TsInterface
 
 static const String X_AMZ_CONTENT_SHA256 = "x-amz-content-sha256";
 static const String X_AMX_DATE           = "x-amz-date";
+static const String X_AMZ_SECURITY_TOKEN = "x-amz-security-token";
 static const String X_AMZ                = "x-amz-";
 static const String CONTENT_TYPE         = "content-type";
 static const String HOST                 = "host";

plugins/s3_auth/s3_auth.cc

@@ -172,9 +172,10 @@ class S3Config
 
   ~S3Config()
   {
-    _secret_len = _keyid_len = 0;
+    _secret_len = _keyid_len = _token_len = 0;
     TSfree(_secret);
     TSfree(_keyid);
+    TSfree(_token);
     if (_cont) {
       TSContDestroy(_cont);
     }
@@ -200,6 +201,9 @@ class S3Config
       if (_region_map_modified && !_region_map.empty()) {
         TSError("[%s] region map is not used with AWS auth v2, parameter ignored", PLUGIN_NAME);
       }
+      if (nullptr != _token || _token_len > 0) {
+        TSError("[%s] session token support with AWS auth v2 is not implemented, parameter ignored", PLUGIN_NAME);
+      }
     } else {
       /* 4 == _version */
       if (_virt_host_modified) {
@@ -240,6 +244,11 @@ class S3Config
       _keyid_len = src->_keyid_len;
     }
 
+    if (src->_token) {
+      _token     = TSstrdup(src->_token);
+      _token_len = src->_token_len;
+    }
+
     if (src->_version_modified) {
       _version          = src->_version;
       _version_modified = true;
@@ -285,6 +294,12 @@ class S3Config
     return _keyid;
   }
 
+  const char *
+  token() const
+  {
+    return _token;
+  }
+
   int
   secret_len() const
   {
@@ -297,6 +312,12 @@ class S3Config
     return _keyid_len;
   }
 
+  int
+  token_len() const
+  {
+    return _token_len;
+  }
+
   int
   version() const
   {
@@ -337,6 +358,13 @@ class S3Config
     _keyid_len = strlen(s);
   }
   void
+  set_token(const char *s)
+  {
+    TSfree(_token);
+    _token     = TSstrdup(s);
+    _token_len = strlen(s);
+  }
+  void
   set_virt_host(bool f = true)
   {
     _virt_host          = f;
@@ -392,6 +420,8 @@ class S3Config
   size_t _secret_len       = 0;
   char *_keyid             = nullptr;
   size_t _keyid_len        = 0;
+  char *_token             = nullptr;
+  size_t _token_len        = 0;
   bool _virt_host          = false;
   int _version             = 2;
   bool _version_modified   = false;
@@ -448,6 +478,8 @@ S3Config::parse_config(const std::string &config_fname)
         set_secret(pos2 + 11);
       } else if (0 == strncasecmp(pos2, "access_key=", 11)) {
         set_keyid(pos2 + 11);
+      } else if (0 == strncasecmp(pos2, "session_token=", 14)) {
+        set_token(pos2 + 14);
       } else if (0 == strncasecmp(pos2, "version=", 8)) {
         set_version(pos2 + 8);
       } else if (0 == strncasecmp(pos2, "virtual_host", 12)) {
@@ -666,6 +698,12 @@ S3Request::authorizeV4(S3Config *s3)
     return TS_HTTP_STATUS_INTERNAL_SERVER_ERROR;
   }
 
+  /* set X-Amz-Security-Token if we have a token */
+  if (nullptr != s3->token() && '\0' != *(s3->token()) &&
+      !set_header(X_AMZ_SECURITY_TOKEN.data(), X_AMZ_SECURITY_TOKEN.size(), s3->token(), s3->token_len())) {
+    return TS_HTTP_STATUS_INTERNAL_SERVER_ERROR;
+  }
+
   String auth = util.getAuthorizationHeader();
   if (auth.empty()) {
     return TS_HTTP_STATUS_INTERNAL_SERVER_ERROR;
@@ -927,6 +965,7 @@ TSRemapNewInstance(int argc, char *argv[], void **ih, char * /* errbuf ATS_UNUSE
     {const_cast<char *>("v4-include-headers"), required_argument, nullptr, 'i'},
     {const_cast<char *>("v4-exclude-headers"), required_argument, nullptr, 'e'},
     {const_cast<char *>("v4-region-map"), required_argument, nullptr, 'm'},
+    {const_cast<char *>("session_token"), required_argument, nullptr, 't'},
     {nullptr, no_argument, nullptr, '\0'},
   };
 
@@ -957,6 +996,9 @@ TSRemapNewInstance(int argc, char *argv[], void **ih, char * /* errbuf ATS_UNUSE
     case 's':
       s3->set_secret(optarg);
       break;
+    case 't':
+      s3->set_token(optarg);
+      break;
     case 'h':
       s3->set_virt_host();
       break;