[dak/master] Add replay protection for uploaded changes files.

[Ansgar Burchardt <ansgar@debian.org>]

Look in signature_history table if the changes was already seen to
prevent re-uploading old changes files.
---
 daklib/checks.py |   13 +++++++++++++
 daklib/dbconn.py |    3 +++
 daklib/upload.py |    8 ++++++++
 3 files changed, 24 insertions(+)

diff --git a/daklib/checks.py b/daklib/checks.py
index dce112b..b7931f2 100644
--- a/daklib/checks.py
+++ b/daklib/checks.py
@@ -109,6 +109,18 @@ class Check(object):
         return False
 
 class SignatureAndHashesCheck(Check):
+    def check_replay(self, upload):
+        # Use private session as we want to remember having seen the .changes
+        # in all cases.
+        session = DBConn().session()
+        history = SignatureHistory.from_signed_file(upload.changes)
+        r = history.query(session)
+        if r is not None:
+            raise Reject('Signature for changes file was already seen at {0}'.format(r.seen))
+        session.add(history)
+        session.commit()
+        return True
+
     """Check signature of changes and dsc file (if included in upload)
 
     Make sure the signature is valid and done by a known user.
@@ -117,6 +129,7 @@ class SignatureAndHashesCheck(Check):
         changes = upload.changes
         if not changes.valid_signature:
             raise Reject("Signature for .changes not valid.")
+        self.check_replay(upload)
         self._check_hashes(upload, changes.filename, changes.files.itervalues())
 
         source = None
diff --git a/daklib/dbconn.py b/daklib/dbconn.py
index e55c283..c2621e3 100644
--- a/daklib/dbconn.py
+++ b/daklib/dbconn.py
@@ -1859,6 +1859,9 @@ class SignatureHistory(ORMObject):
         self.contents_sha1 = signed_file.contents_sha1()
         return self
 
+    def query(self, session):
+        return session.query(SignatureHistory).filter_by(fingerprint=self.fingerprint, signature_timestamp=self.signature_timestamp, contents_sha1=self.contents_sha1).first()
+
 __all__.append('SignatureHistory')
 
 ################################################################################
diff --git a/daklib/upload.py b/daklib/upload.py
index 406b1d4..ec120a7 100644
--- a/daklib/upload.py
+++ b/daklib/upload.py
@@ -275,6 +275,14 @@ class Changes(object):
         return self._signed_file.valid
 
     @property
+    def signature_timestamp(self):
+        return self._signed_file.signature_timestamp
+
+    @property
+    def contents_sha1(self):
+        return self._signed_file.contents_sha1
+
+    @property
     def architectures(self):
         """list of architectures included in the upload
         @type: list of str
-- 
1.7.10.4