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authorMark Haines <mjark@negativecurvature.net>2016-10-20 09:58:55 +0100
committerMark Haines <mjark@negativecurvature.net>2016-10-20 09:58:55 +0100
commit653790eacbf7dcf94cbf181657cdb0c30c890c3f (patch)
tree6cf8ca49bff13c01d18c15cd8e1a5e53c1cf9167
parent6ea9fb450ec1ef10b32d65ceb00a6042b927a95c (diff)
Return the message index when decrypting group messages.
Applications can use the index to detect replays of the same message.
-rw-r--r--include/olm/inbound_group_session.h3
-rw-r--r--javascript/demo/group_demo.js4
-rw-r--r--javascript/olm_inbound_group_session.js9
-rwxr-xr-xpython/olm/__main__.py2
-rw-r--r--python/olm/inbound_group_session.py8
-rw-r--r--src/inbound_group_session.c11
-rw-r--r--tests/test_group_session.cpp8
7 files changed, 31 insertions, 14 deletions
diff --git a/include/olm/inbound_group_session.h b/include/olm/inbound_group_session.h
index 59146c2..f8a0bc3 100644
--- a/include/olm/inbound_group_session.h
+++ b/include/olm/inbound_group_session.h
@@ -140,7 +140,8 @@ size_t olm_group_decrypt(
uint8_t * message, size_t message_length,
/* output */
- uint8_t * plaintext, size_t max_plaintext_length
+ uint8_t * plaintext, size_t max_plaintext_length,
+ uint32_t * message_index
);
diff --git a/javascript/demo/group_demo.js b/javascript/demo/group_demo.js
index 1b8f7ab..42a3d84 100644
--- a/javascript/demo/group_demo.js
+++ b/javascript/demo/group_demo.js
@@ -403,8 +403,8 @@ DemoUser.prototype.decryptGroup = function(jsonpacket, callback) {
throw new Error("Unknown session id " + session_id);
}
- var plaintext = session.decrypt(packet.body);
- done(plaintext);
+ var result = session.decrypt(packet.body);
+ done(result.plaintext);
}, callback);
};
diff --git a/javascript/olm_inbound_group_session.js b/javascript/olm_inbound_group_session.js
index 6058233..1b7fcfe 100644
--- a/javascript/olm_inbound_group_session.js
+++ b/javascript/olm_inbound_group_session.js
@@ -73,10 +73,12 @@ InboundGroupSession.prototype['decrypt'] = restore_stack(function(
// So we copy the array to a new buffer
var message_buffer = stack(message_array);
var plaintext_buffer = stack(max_plaintext_length + NULL_BYTE_PADDING_LENGTH);
+ var message_index = stack(4);
var plaintext_length = inbound_group_session_method(Module["_olm_group_decrypt"])(
this.ptr,
message_buffer, message_array.length,
- plaintext_buffer, max_plaintext_length
+ plaintext_buffer, max_plaintext_length,
+ message_index
);
// Pointer_stringify requires a null-terminated argument (the optional
@@ -86,7 +88,10 @@ InboundGroupSession.prototype['decrypt'] = restore_stack(function(
0, "i8"
);
- return Pointer_stringify(plaintext_buffer);
+ return {
+ "plaintext": Pointer_stringify(plaintext_buffer),
+ "message_index": Module['getValue'](message_index, "i32")
+ }
});
InboundGroupSession.prototype['session_id'] = restore_stack(function() {
diff --git a/python/olm/__main__.py b/python/olm/__main__.py
index cf9158d..eb76301 100755
--- a/python/olm/__main__.py
+++ b/python/olm/__main__.py
@@ -328,7 +328,7 @@ def do_group_decrypt(args):
session = InboundGroupSession()
session.unpickle(args.key, read_base64_file(args.session_file))
message = args.message_file.read()
- plaintext = session.decrypt(message)
+ plaintext, message_index = session.decrypt(message)
with open(args.session_file, "wb") as f:
f.write(session.pickle(args.key))
args.plaintext_file.write(plaintext)
diff --git a/python/olm/inbound_group_session.py b/python/olm/inbound_group_session.py
index d5547fd..27a569c 100644
--- a/python/olm/inbound_group_session.py
+++ b/python/olm/inbound_group_session.py
@@ -43,6 +43,7 @@ inbound_group_session_function(
lib.olm_group_decrypt,
c_void_p, c_size_t, # message
c_void_p, c_size_t, # plaintext
+ POINTER(c_uint32), # message_index
)
inbound_group_session_function(lib.olm_inbound_group_session_id_length)
@@ -82,11 +83,14 @@ class InboundGroupSession(object):
)
plaintext_buffer = create_string_buffer(max_plaintext_length)
message_buffer = create_string_buffer(message)
+
+ message_index = c_uint32()
plaintext_length = lib.olm_group_decrypt(
self.ptr, message_buffer, len(message),
- plaintext_buffer, max_plaintext_length
+ plaintext_buffer, max_plaintext_length,
+ byref(message_index)
)
- return plaintext_buffer.raw[:plaintext_length]
+ return plaintext_buffer.raw[:plaintext_length], message_index
def session_id(self):
id_length = lib.olm_inbound_group_session_id_length(self.ptr)
diff --git a/src/inbound_group_session.c b/src/inbound_group_session.c
index bf00008..ed313a0 100644
--- a/src/inbound_group_session.c
+++ b/src/inbound_group_session.c
@@ -263,7 +263,8 @@ size_t olm_group_decrypt_max_plaintext_length(
static size_t _decrypt(
OlmInboundGroupSession *session,
uint8_t * message, size_t message_length,
- uint8_t * plaintext, size_t max_plaintext_length
+ uint8_t * plaintext, size_t max_plaintext_length,
+ uint32_t * message_index
) {
struct _OlmDecodeGroupMessageResults decoded_results;
size_t max_length, r;
@@ -286,6 +287,8 @@ static size_t _decrypt(
return (size_t)-1;
}
+ *message_index = decoded_results.message_index;
+
/* verify the signature. We could do this before decoding the message, but
* we allow for the possibility of future protocol versions which use a
* different signing mechanism; we would rather throw "BAD_MESSAGE_VERSION"
@@ -349,7 +352,8 @@ static size_t _decrypt(
size_t olm_group_decrypt(
OlmInboundGroupSession *session,
uint8_t * message, size_t message_length,
- uint8_t * plaintext, size_t max_plaintext_length
+ uint8_t * plaintext, size_t max_plaintext_length,
+ uint32_t * message_index
) {
size_t raw_message_length;
@@ -361,7 +365,8 @@ size_t olm_group_decrypt(
return _decrypt(
session, message, raw_message_length,
- plaintext, max_plaintext_length
+ plaintext, max_plaintext_length,
+ message_index
);
}
diff --git a/tests/test_group_session.cpp b/tests/test_group_session.cpp
index 9930927..b15875c 100644
--- a/tests/test_group_session.cpp
+++ b/tests/test_group_session.cpp
@@ -161,8 +161,9 @@ int main() {
memcpy(msgcopy, msg, msglen);
size = olm_group_decrypt_max_plaintext_length(inbound_session, msgcopy, msglen);
uint8_t plaintext_buf[size];
+ uint32_t message_index;
res = olm_group_decrypt(inbound_session, msg, msglen,
- plaintext_buf, size);
+ plaintext_buf, size, &message_index);
assert_equals(plaintext_length, res);
assert_equals(plaintext, plaintext_buf, res);
}
@@ -208,8 +209,9 @@ int main() {
memcpy(msgcopy, message, msglen);
uint8_t plaintext_buf[size];
+ uint32_t message_index;
res = olm_group_decrypt(
- inbound_session, msgcopy, msglen, plaintext_buf, size
+ inbound_session, msgcopy, msglen, plaintext_buf, size, &message_index
);
assert_equals(plaintext_length, res);
assert_equals(plaintext, plaintext_buf, res);
@@ -227,7 +229,7 @@ int main() {
memcpy(msgcopy, message, msglen);
res = olm_group_decrypt(
inbound_session, msgcopy, msglen,
- plaintext_buf, size
+ plaintext_buf, size, &message_index
);
assert_equals((size_t)-1, res);
assert_equals(