Adding the repoint function, and some tests. Fixing the list of tests

crypt4gh/__main__.py

@@ -13,7 +13,7 @@ def main(argv=sys.argv[1:]):
         args = cli.parse_args(argv)
 
         # Main Commands
-        for command in ('encrypt', 'decrypt', 'rearrange', 'reencrypt'):
+        for command in ('encrypt', 'decrypt', 'rearrange', 'reencrypt', 'repoint'):
             if args.get(command):
                 cmd = getattr(cli,command,None)
                 if not cmd:

crypt4gh/cli.py

@@ -29,8 +29,9 @@
 Usage:
    {PROG} [-hv] [--log <file>] encrypt [--sk <path>] --recipient_pk <path> [--recipient_pk <path>]... [--range <start-end>] [--header <path>] [--expiration <date>] [--uri <path>]
    {PROG} [-hv] [--log <file>] decrypt [--sk <path>] [--sender_pk <path>] [--range <start-end>]
-   {PROG} [-hv] [--log <file>] rearrange [--sk <path>] --range <start-end>
    {PROG} [-hv] [--log <file>] reencrypt [--sk <path>] --recipient_pk <path> [--recipient_pk <path>]... [--trim] [--header-only]
+   {PROG} [-hv] [--log <file>] rearrange [--sk <path>] --range <start-end>
+   {PROG} [-hv] [--log <file>] repoint [--sk <path>] --uri <path>
 
 Options:
    -h, --help             Prints this help and exit
@@ -84,9 +85,6 @@ def parse_args(argv=sys.argv[1:]):
     if args['--range'] is not None and args['--uri'] is not None:
         raise ValueError('Can not mix --range and --uri')
 
-    if args['--uri'] is not None and args['--header'] is None:
-        raise ValueError('--uri requires --header')
-
     # print(args)
     return args
 
@@ -140,6 +138,9 @@ def make_timestamp(date):
 def encrypt(args):
     assert( args['encrypt'] )
 
+    if args['--uri'] is not None and args['--header'] is None:
+        raise ValueError('--uri requires --header')
+
     range_start, range_span = parse_range(args)
 
     seckey = retrieve_private_key(args, generate=True)
@@ -245,3 +246,19 @@ def build_recipients():
                   sys.stdout.buffer,
                   trim=args['--trim'],
                   header_only=args['--header-only'])
+
+def repoint(args):
+    assert( args['repoint'] )
+
+    # if args['--uri'] is None: 
+    #     raise ValueError('--uri is required')
+
+    seckey = retrieve_private_key(args)
+
+    keys = [(0, seckey, bytes(PrivateKey(seckey).public_key))] # keys = list of (method, privkey, recipient_pubkey=ourselves)
+
+    lib.repoint(keys,
+                sys.stdin.buffer,
+                sys.stdout.buffer,
+                args['--uri'])
+

crypt4gh/header.py

@@ -468,3 +468,43 @@ def segment_oracle():
     return packets, segment_oracle()
 
 
+# -------------------------------------
+# Header Re-Arrange
+# -------------------------------------
+
+def repoint(header_packets, keys, uri, sender_pubkey=None):
+    '''
+    Re-point the link to the given URI.
+    
+    :returns: the packet list as-is, replacing with (or adding) a new link packet.
+
+    Note: we trim the packets we couldn't decrypt
+    '''
+
+    LOG.info('Repointing the header to URI: %s', uri)
+
+    decrypted_packets, _ = decrypt(header_packets, keys, sender_pubkey=sender_pubkey)
+
+    if not decrypted_packets:
+        raise ValueError('No header packet could be decrypted')
+
+    data_packets, edits, timestamp, link = extract(decrypted_packets)
+
+    if link is None:
+        LOG.warning('Ignoring existing link poiting to %s', link)
+
+
+    LOG.info('Reencrypting all packets')
+
+    packets = [PACKET_TYPE_DATA_ENC + packet for packet in data_packets]
+    packets.append(make_packet_link(uri)) # Adding a new URI
+    if timestamp is not None:
+        packets.append(make_packet_timestamp(timestamp))
+    if edits is not None:
+        packets.append(make_packet_data_edit_list(edits))
+
+    packets = [encrypted_packet for packet in packets for encrypted_packet in encrypt(packet, keys)]
+
+    return packets
+
+

crypt4gh/lib.py

@@ -494,3 +494,28 @@ def rearrange(keys, infile, outfile, offset=0, span=None):
     del segment_oracle # enough to terminate and remove it?
     LOG.info('Rearrangement Successful')
 
+
+##############################################################
+##
+##   Adding or Updating an URI in the header
+##
+##############################################################
+
+@close_on_broken_pipe
+def repoint(keys, infile, outfile, uri):
+    '''Extract header packets from infile, replacing with (or adding) a new link packet.
+    The new header is sent to the outfile.
+    '''
+
+    # Decrypt and re-encrypt the header
+    header_packets = header.parse(infile)
+
+    packets = header.repoint(header_packets, keys, uri)
+    outfile.write(header.serialize(packets))
+
+    remainder = infile.read(1)
+    if not remainder:
+        LOG.info('Repointing Successful')
+    else:
+        LOG.warning('Not at the end of the file: Truncating here')
+

tests/README.md

@@ -66,4 +66,23 @@ We use the testfile and Bob encrypts it for himself.
       Expected outcome: They both can read the same content as Bob had.
 
 
+## Payload as URI
+
+
+- [x] Bob sends the testfile secretly Alice, over an URI<br/>
+      Expected outcome: Alice reads the same content as testfile.
+
+- [x] Bob sends the testfile secretly Alice, over an URI, and moves its payload.<br/>
+      Expected outcome: Alice repoints to the new URI and reads the same content as testfile.
+
+## Expiration dates
+
+
+- [x] Bob sends the testfile secretly Alice, with a past expiration date<br/>
+      Expected outcome: Alice can't decrypt the file.
+
+- [x] Bob sends the testfile secretly Alice, with a future expiration date<br/>
+      Expected outcome: Alice reads the same content as testfile.
+
+
 

tests/uri.bats

@@ -31,3 +31,32 @@ function teardown() {
 
     unset C4GH_PASSPHRASE
 }
+
+@test "Bob sends the testfile secretly to Alice over an URI, and repoints it" {
+
+    TESTFILE=${BATS_TEST_DIRNAME}/_common/testfile.abcd
+
+    # Bob encrypts the testfile for Alice
+    export C4GH_PASSPHRASE=${BOB_PASSPHRASE}
+    crypt4gh encrypt --recipient_pk ${ALICE_PUBKEY} --uri "file://$TESTFILES/message.c4gh.payload" --header "$TESTFILES/message.c4gh.header" < $TESTFILE > $TESTFILES/message.c4gh.payload
+
+    # Bob moves the testfile payload
+    mv $TESTFILES/message.c4gh.payload $TESTFILES/message.c4gh.payload.new
+
+    # Alice repoints the testfile to the new URI
+    export C4GH_PASSPHRASE=${ALICE_PASSPHRASE}
+    crypt4gh repoint --sk ${ALICE_SECKEY} --uri "file://$TESTFILES/message.c4gh.payload.new" < $TESTFILES/message.c4gh.header > $TESTFILES/message.c4gh.header.new
+
+    # Alice decrypts it
+    # export C4GH_PASSPHRASE=${ALICE_PASSPHRASE}
+    crypt4gh decrypt --sk ${ALICE_SECKEY} < $TESTFILES/message.c4gh.header.new > $TESTFILES/message.alice.received
+
+    run diff $TESTFILE $TESTFILES/message.alice.received
+    [ "$status" -eq 0 ]
+
+    # Alice can't access the old URI
+    run crypt4gh decrypt --sk ${ALICE_SECKEY} < $TESTFILES/message.c4gh.header
+    [ "$status" -ne 0 ]
+
+    unset C4GH_PASSPHRASE
+}