X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/7a98271d94163cdc4afa5bfcf275db353bc062d2..cec011b7718536de42ebd683aa96bee92cbca06c:/services/api/app/models/blob.rb

diff --git a/services/api/app/models/blob.rb b/services/api/app/models/blob.rb
index 11fab9fb59..55a257856c 100644
--- a/services/api/app/models/blob.rb
+++ b/services/api/app/models/blob.rb
@@ -1,4 +1,19 @@
+# Copyright (C) The Arvados Authors. All rights reserved.
+#
+# SPDX-License-Identifier: AGPL-3.0
+
+require 'request_error'
+
 class Blob
+  extend DbCurrentTime
+
+  def initialize locator
+    @locator = locator
+  end
+
+  def empty?
+    !!@locator.match(/^d41d8cd98f00b204e9800998ecf8427e(\+.*)?$/)
+  end
 
   # In order to get a Blob from Keep, you have to prove either
   # [a] you have recently written it to Keep yourself, or
@@ -12,30 +27,42 @@ class Blob
   #     locator_hash +A blob_signature @ timestamp
   # where the timestamp is a Unix time expressed as a hexadecimal value,
   # and the blob_signature is the signed locator_hash + API token + timestamp.
-  # 
-  class InvalidSignatureError < StandardError
+  #
+  class InvalidSignatureError < RequestError
   end
 
   # Blob.sign_locator: return a signed and timestamped blob locator.
   #
   # The 'opts' argument should include:
-  #   [required] :key       - the Arvados server-side blobstore key
-  #   [required] :api_token - user's API token
-  #   [optional] :ttl       - number of seconds before this request expires
+  #   [required] :api_token - API token (signatures only work for this token)
+  #   [optional] :key       - the Arvados server-side blobstore key
+  #   [optional] :ttl       - number of seconds before signature should expire
+  #   [optional] :expire    - unix timestamp when signature should expire
   #
   def self.sign_locator blob_locator, opts
     # We only use the hash portion for signatures.
     blob_hash = blob_locator.split('+').first
 
-    # Generate an expiry timestamp (seconds since epoch, base 16)
-    timestamp = (Time.now.to_i + (opts[:ttl] || 600)).to_s(16)
+    # Generate an expiry timestamp (seconds after epoch, base 16)
+    if opts[:expire]
+      if opts[:ttl]
+        raise "Cannot specify both :ttl and :expire options"
+      end
+      timestamp = opts[:expire]
+    else
+      timestamp = db_current_time.to_i +
+        (opts[:ttl] || Rails.configuration.blob_signature_ttl)
+    end
+    timestamp_hex = timestamp.to_s(16)
     # => "53163cb4"
+    blob_signature_ttl = Rails.configuration.blob_signature_ttl.to_s(16)
 
     # Generate a signature.
     signature =
-      generate_signature opts[:key], blob_hash, opts[:api_token], timestamp
+      generate_signature((opts[:key] or Rails.configuration.blob_signing_key),
+                         blob_hash, opts[:api_token], timestamp_hex, blob_signature_ttl)
 
-    blob_locator + '+A' + signature + '@' + timestamp
+    blob_locator + '+A' + signature + '@' + timestamp_hex
   end
 
   # Blob.verify_signature
@@ -43,9 +70,9 @@ class Blob
   #   Return value: true if the locator has a valid signature, false otherwise
   #   Arguments: signed_blob_locator, opts
   #
-  def self.verify_signature *args
+  def self.verify_signature(*args)
     begin
-      self.verify_signature! *args
+      self.verify_signature!(*args)
       true
     rescue Blob::InvalidSignatureError
       false
@@ -70,15 +97,17 @@ class Blob
     if !timestamp
       raise Blob::InvalidSignatureError.new 'No signature provided.'
     end
-    if !timestamp.match /^[\da-f]+$/
+    unless timestamp =~ /^[\da-f]+$/
       raise Blob::InvalidSignatureError.new 'Timestamp is not a base16 number.'
     end
-    if timestamp.to_i(16) < Time.now.to_i
+    if timestamp.to_i(16) < (opts[:now] or db_current_time.to_i)
       raise Blob::InvalidSignatureError.new 'Signature expiry time has passed.'
     end
+    blob_signature_ttl = Rails.configuration.blob_signature_ttl.to_s(16)
 
     my_signature =
-      generate_signature opts[:key], blob_hash, opts[:api_token], timestamp
+      generate_signature((opts[:key] or Rails.configuration.blob_signing_key),
+                         blob_hash, opts[:api_token], timestamp, blob_signature_ttl)
 
     if my_signature != given_signature
       raise Blob::InvalidSignatureError.new 'Signature is invalid.'
@@ -87,10 +116,11 @@ class Blob
     true
   end
 
-  def self.generate_signature key, blob_hash, api_token, timestamp
+  def self.generate_signature key, blob_hash, api_token, timestamp, blob_signature_ttl
     OpenSSL::HMAC.hexdigest('sha1', key,
                             [blob_hash,
                              api_token,
-                             timestamp].join('@'))
+                             timestamp,
+                             blob_signature_ttl].join('@'))
   end
 end