Commit 1d4c13c7 authored by Richard van der Hoff's avatar Richard van der Hoff
Browse files

Fix megolm decryption of UTF-8

Repeat the fix from b10f90d for megolm messages.

It turns out that the 'length' argument to 'Pointer_stringify' doesn't work if
the input includes characters >= 128.

Rather than try to figure out which methods can return UTF-8, and which always
return plain ascii, replace all uses of Pointer_stringify with a 'length'
argument with the version that expects a NULL-terminated input, and extend the
buffer by a byte to allow space for a null-terminator.

In the case of decrypt, we need to add the null ourself.

Fixes https://github.com/vector-im/vector-web/issues/2078.
parent 0c3f527d
/* The 'length' argument to Pointer_stringify doesn't work if the input includes
* characters >= 128; we therefore need to add a NULL character to all of our
* strings. This acts as a symbolic constant to help show what we're doing.
*/
var NULL_BYTE_PADDING_LENGTH = 1;
function InboundGroupSession() { function InboundGroupSession() {
var size = Module['_olm_inbound_group_session_size'](); var size = Module['_olm_inbound_group_session_size']();
this.buf = malloc(size); this.buf = malloc(size);
...@@ -28,11 +34,11 @@ InboundGroupSession.prototype['pickle'] = restore_stack(function(key) { ...@@ -28,11 +34,11 @@ InboundGroupSession.prototype['pickle'] = restore_stack(function(key) {
Module['_olm_pickle_inbound_group_session_length'] Module['_olm_pickle_inbound_group_session_length']
)(this.ptr); )(this.ptr);
var key_buffer = stack(key_array); var key_buffer = stack(key_array);
var pickle_buffer = stack(pickle_length); var pickle_buffer = stack(pickle_length + NULL_BYTE_PADDING_LENGTH);
inbound_group_session_method(Module['_olm_pickle_inbound_group_session'])( inbound_group_session_method(Module['_olm_pickle_inbound_group_session'])(
this.ptr, key_buffer, key_array.length, pickle_buffer, pickle_length this.ptr, key_buffer, key_array.length, pickle_buffer, pickle_length
); );
return Pointer_stringify(pickle_buffer, pickle_length); return Pointer_stringify(pickle_buffer);
}); });
InboundGroupSession.prototype['unpickle'] = restore_stack(function(key, pickle) { InboundGroupSession.prototype['unpickle'] = restore_stack(function(key, pickle) {
...@@ -66,13 +72,21 @@ InboundGroupSession.prototype['decrypt'] = restore_stack(function( ...@@ -66,13 +72,21 @@ InboundGroupSession.prototype['decrypt'] = restore_stack(function(
// caculating the length destroys the input buffer. // caculating the length destroys the input buffer.
// So we copy the array to a new buffer // So we copy the array to a new buffer
var message_buffer = stack(message_array); var message_buffer = stack(message_array);
var plaintext_buffer = stack(max_plaintext_length); var plaintext_buffer = stack(max_plaintext_length + NULL_BYTE_PADDING_LENGTH);
var plaintext_length = session_method(Module["_olm_group_decrypt"])( var plaintext_length = session_method(Module["_olm_group_decrypt"])(
this.ptr, this.ptr,
message_buffer, message_array.length, message_buffer, message_array.length,
plaintext_buffer, max_plaintext_length plaintext_buffer, max_plaintext_length
); );
return Pointer_stringify(plaintext_buffer, plaintext_length);
// Pointer_stringify requires a null-terminated argument (the optional
// 'len' argument doesn't work for UTF-8 data).
Module['setValue'](
plaintext_buffer+plaintext_length,
0, "i8"
);
return Pointer_stringify(plaintext_buffer);
}); });
olm_exports['InboundGroupSession'] = InboundGroupSession; olm_exports['InboundGroupSession'] = InboundGroupSession;
/* The 'length' argument to Pointer_stringify doesn't work if the input includes
* characters >= 128; we therefore need to add a NULL character to all of our
* strings. This acts as a symbolic constant to help show what we're doing.
*/
var NULL_BYTE_PADDING_LENGTH = 1;
function OutboundGroupSession() { function OutboundGroupSession() {
var size = Module['_olm_outbound_group_session_size'](); var size = Module['_olm_outbound_group_session_size']();
...@@ -29,11 +35,11 @@ OutboundGroupSession.prototype['pickle'] = restore_stack(function(key) { ...@@ -29,11 +35,11 @@ OutboundGroupSession.prototype['pickle'] = restore_stack(function(key) {
Module['_olm_pickle_outbound_group_session_length'] Module['_olm_pickle_outbound_group_session_length']
)(this.ptr); )(this.ptr);
var key_buffer = stack(key_array); var key_buffer = stack(key_array);
var pickle_buffer = stack(pickle_length); var pickle_buffer = stack(pickle_length + NULL_BYTE_PADDING_LENGTH);
outbound_group_session_method(Module['_olm_pickle_outbound_group_session'])( outbound_group_session_method(Module['_olm_pickle_outbound_group_session'])(
this.ptr, key_buffer, key_array.length, pickle_buffer, pickle_length this.ptr, key_buffer, key_array.length, pickle_buffer, pickle_length
); );
return Pointer_stringify(pickle_buffer, pickle_length); return Pointer_stringify(pickle_buffer);
}); });
OutboundGroupSession.prototype['unpickle'] = restore_stack(function(key, pickle) { OutboundGroupSession.prototype['unpickle'] = restore_stack(function(key, pickle) {
...@@ -63,35 +69,35 @@ OutboundGroupSession.prototype['encrypt'] = restore_stack(function(plaintext) { ...@@ -63,35 +69,35 @@ OutboundGroupSession.prototype['encrypt'] = restore_stack(function(plaintext) {
Module['_olm_group_encrypt_message_length'] Module['_olm_group_encrypt_message_length']
)(this.ptr, plaintext_array.length); )(this.ptr, plaintext_array.length);
var plaintext_buffer = stack(plaintext_array); var plaintext_buffer = stack(plaintext_array);
var message_buffer = stack(message_length); var message_buffer = stack(message_length + NULL_BYTE_PADDING_LENGTH);
outbound_group_session_method(Module['_olm_group_encrypt'])( outbound_group_session_method(Module['_olm_group_encrypt'])(
this.ptr, this.ptr,
plaintext_buffer, plaintext_array.length, plaintext_buffer, plaintext_array.length,
message_buffer, message_length message_buffer, message_length
); );
return Pointer_stringify(message_buffer, message_length); return Pointer_stringify(message_buffer);
}); });
OutboundGroupSession.prototype['session_id'] = restore_stack(function(key) { OutboundGroupSession.prototype['session_id'] = restore_stack(function(key) {
var length = outbound_group_session_method( var length = outbound_group_session_method(
Module['_olm_outbound_group_session_id_length'] Module['_olm_outbound_group_session_id_length']
)(this.ptr); )(this.ptr);
var session_id = stack(length); var session_id = stack(length + NULL_BYTE_PADDING_LENGTH);
outbound_group_session_method(Module['_olm_outbound_group_session_id'])( outbound_group_session_method(Module['_olm_outbound_group_session_id'])(
this.ptr, session_id, length this.ptr, session_id, length
); );
return Pointer_stringify(session_id, length); return Pointer_stringify(session_id);
}); });
OutboundGroupSession.prototype['session_key'] = restore_stack(function(key) { OutboundGroupSession.prototype['session_key'] = restore_stack(function(key) {
var key_length = outbound_group_session_method( var key_length = outbound_group_session_method(
Module['_olm_outbound_group_session_key_length'] Module['_olm_outbound_group_session_key_length']
)(this.ptr); )(this.ptr);
var key = stack(key_length); var key = stack(key_length + NULL_BYTE_PADDING_LENGTH);
outbound_group_session_method(Module['_olm_outbound_group_session_key'])( outbound_group_session_method(Module['_olm_outbound_group_session_key'])(
this.ptr, key, key_length this.ptr, key, key_length
); );
return Pointer_stringify(key, key_length); return Pointer_stringify(key);
}); });
OutboundGroupSession.prototype['message_index'] = function() { OutboundGroupSession.prototype['message_index'] = function() {
......
...@@ -5,7 +5,7 @@ var Pointer_stringify = Module['Pointer_stringify']; ...@@ -5,7 +5,7 @@ var Pointer_stringify = Module['Pointer_stringify'];
var OLM_ERROR = Module['_olm_error'](); var OLM_ERROR = Module['_olm_error']();
/* The 'length' argument to Pointer_stringify doesn't work if the input includes /* The 'length' argument to Pointer_stringify doesn't work if the input includes
* cahracters >= 128; we therefore need to add a NULL character to all of our * characters >= 128; we therefore need to add a NULL character to all of our
* strings. This acts as a symbolic constant to help show what we're doing. * strings. This acts as a symbolic constant to help show what we're doing.
*/ */
var NULL_BYTE_PADDING_LENGTH = 1; var NULL_BYTE_PADDING_LENGTH = 1;
......
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