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Merge pull request #39 from matrix-org/rav/messages_on_heap

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Allocate memory for message blobs on the heap
This commit is contained in:
Richard van der Hoff 2016-12-15 16:54:39 +00:00 committed by GitHub
commit 7fd63bcac7
3 changed files with 168 additions and 88 deletions
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42
javascript/olm_inbound_group_session.js
View file

@ -64,34 +64,52 @@ InboundGroupSession.prototype['create'] = restore_stack(function(session_key) {
InboundGroupSession.prototype['decrypt'] = restore_stack(function(
message
) {
var message_array = array_from_string(message);
var message_buffer = stack(message_array);
var message_buffer, plaintext_buffer, plaintext_length;
try {
message_buffer = malloc(message.length);
Module['writeAsciiToMemory'](message, message_buffer, true);
var max_plaintext_length = inbound_group_session_method(
Module['_olm_group_decrypt_max_plaintext_length']
)(this.ptr, message_buffer, message_array.length);
// caculating the length destroys the input buffer.
// 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);
)(this.ptr, message_buffer, message.length);
// caculating the length destroys the input buffer, so we need to re-copy it.
Module['writeAsciiToMemory'](message, message_buffer, true);
plaintext_buffer = malloc(max_plaintext_length + NULL_BYTE_PADDING_LENGTH);
var message_index = stack(4);
var plaintext_length = inbound_group_session_method(Module["_olm_group_decrypt"])(
plaintext_length = inbound_group_session_method(
Module["_olm_group_decrypt"]
)(
this.ptr,
message_buffer, message_array.length,
message_buffer, message.length,
plaintext_buffer, max_plaintext_length,
message_index
);
// Pointer_stringify requires a null-terminated argument (the optional
// 'len' argument doesn't work for UTF-8 data).
// UTF8ToString requires a null-terminated argument, so add the
// null terminator.
Module['setValue'](
plaintext_buffer+plaintext_length,
0, "i8"
);
return {
"plaintext": Pointer_stringify(plaintext_buffer),
"plaintext": UTF8ToString(plaintext_buffer),
"message_index": Module['getValue'](message_index, "i32")
}
} finally {
if (message_buffer !== undefined) {
free(message_buffer);
}
if (plaintext_buffer !== undefined) {
// don't leave a copy of the plaintext in the heap.
bzero(plaintext_buffer, plaintext_length + NULL_BYTE_PADDING_LENGTH);
free(plaintext_buffer);
}
}
});
InboundGroupSession.prototype['session_id'] = restore_stack(function() {

34
javascript/olm_outbound_group_session.js
View file

@ -63,20 +63,38 @@ OutboundGroupSession.prototype['create'] = restore_stack(function() {
);
});
OutboundGroupSession.prototype['encrypt'] = restore_stack(function(plaintext) {
var plaintext_array = array_from_string(plaintext);
OutboundGroupSession.prototype['encrypt'] = function(plaintext) {
var plaintext_buffer, message_buffer, plaintext_length;
try {
plaintext_length = Module['lengthBytesUTF8'](plaintext);
var message_length = outbound_group_session_method(
Module['_olm_group_encrypt_message_length']
)(this.ptr, plaintext_array.length);
var plaintext_buffer = stack(plaintext_array);
var message_buffer = stack(message_length + NULL_BYTE_PADDING_LENGTH);
)(this.ptr, plaintext_length);
// need to allow space for the terminator (which stringToUTF8 always
// writes), hence + 1.
plaintext_buffer = malloc(plaintext_length + 1);
Module['stringToUTF8'](plaintext, plaintext_buffer, plaintext_length + 1);
message_buffer = malloc(message_length + NULL_BYTE_PADDING_LENGTH);
outbound_group_session_method(Module['_olm_group_encrypt'])(
this.ptr,
plaintext_buffer, plaintext_array.length,
plaintext_buffer, plaintext_length,
message_buffer, message_length
);
return Pointer_stringify(message_buffer);
});
return Module['UTF8ToString'](message_buffer);
} finally {
if (plaintext_buffer !== undefined) {
// don't leave a copy of the plaintext in the heap.
bzero(plaintext_buffer, plaintext_length + 1);
free(plaintext_buffer);
}
if (message_buffer !== undefined) {
free(message_buffer);
}
}
};
OutboundGroupSession.prototype['session_id'] = restore_stack(function() {
var length = outbound_group_session_method(

88
javascript/olm_post.js
View file

@ -4,9 +4,11 @@ var free = Module['_free'];
var Pointer_stringify = Module['Pointer_stringify'];
var OLM_ERROR = Module['_olm_error']();
/* 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.
/* The 'length' argument to Pointer_stringify doesn't work if the input
* includes characters >= 128, which makes Pointer_stringify unreliable. We
* could use it on strings which are known to be ascii, but that seems
* dangerous. Instead we add a NULL character to all of our strings and just
* use UTF8ToString.
*/
var NULL_BYTE_PADDING_LENGTH = 1;
@ -40,6 +42,13 @@ function restore_stack(wrapped) {
}
}
/* set a memory area to zero */
function bzero(ptr, n) {
while(n-- > 0) {
Module['HEAP8'][ptr++] = 0;
}
}
function Account() {
var size = Module['_olm_account_size']();
this.buf = malloc(size);
@ -297,59 +306,94 @@ Session.prototype['matches_inbound_from'] = restore_stack(function(
Session.prototype['encrypt'] = restore_stack(function(
plaintext
) {
var plaintext_buffer, message_buffer, plaintext_length;
try {
var random_length = session_method(
Module['_olm_encrypt_random_length']
)(this.ptr);
var message_type = session_method(
Module['_olm_encrypt_message_type']
)(this.ptr);
var plaintext_array = array_from_string(plaintext);
plaintext_length = Module['lengthBytesUTF8'](plaintext);
var message_length = session_method(
Module['_olm_encrypt_message_length']
)(this.ptr, plaintext_array.length);
)(this.ptr, plaintext_length);
var random = random_stack(random_length);
var plaintext_buffer = stack(plaintext_array);
var message_buffer = stack(message_length + NULL_BYTE_PADDING_LENGTH);
// need to allow space for the terminator (which stringToUTF8 always
// writes), hence + 1.
plaintext_buffer = malloc(plaintext_length + 1);
Module['stringToUTF8'](plaintext, plaintext_buffer, plaintext_length + 1);
message_buffer = malloc(message_length + NULL_BYTE_PADDING_LENGTH);
session_method(Module['_olm_encrypt'])(
this.ptr,
plaintext_buffer, plaintext_array.length,
plaintext_buffer, plaintext_length,
random, random_length,
message_buffer, message_length
);
return {
"type": message_type,
"body": Pointer_stringify(message_buffer)
"body": Module['UTF8ToString'](message_buffer),
};
} finally {
if (plaintext_buffer !== undefined) {
// don't leave a copy of the plaintext in the heap.
bzero(plaintext_buffer, plaintext_length + 1);
free(plaintext_buffer);
}
if (message_buffer !== undefined) {
free(message_buffer);
}
}
});
Session.prototype['decrypt'] = restore_stack(function(
message_type, message
) {
var message_array = array_from_string(message);
var message_buffer = stack(message_array);
var max_plaintext_length = session_method(
var message_buffer, plaintext_buffer, max_plaintext_length;
try {
message_buffer = malloc(message.length);
Module['writeAsciiToMemory'](message, message_buffer, true);
max_plaintext_length = session_method(
Module['_olm_decrypt_max_plaintext_length']
)(this.ptr, message_type, message_buffer, message_array.length);
// caculating the length destroys the input buffer.
// 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
);
)(this.ptr, message_type, message_buffer, message.length);
// caculating the length destroys the input buffer, so we need to re-copy it.
Module['writeAsciiToMemory'](message, message_buffer, true);
plaintext_buffer = malloc(max_plaintext_length + NULL_BYTE_PADDING_LENGTH);
var plaintext_length = session_method(Module["_olm_decrypt"])(
this.ptr, message_type,
message_buffer, message.length,
plaintext_buffer, max_plaintext_length
);
// Pointer_stringify requires a null-terminated argument (the optional
// 'len' argument doesn't work for UTF-8 data).
// UTF8ToString requires a null-terminated argument, so add the
// null terminator.
Module['setValue'](
plaintext_buffer+plaintext_length,
0, "i8"
);
return Pointer_stringify(plaintext_buffer);
return UTF8ToString(plaintext_buffer);
} finally {
if (message_buffer !== undefined) {
free(message_buffer);
}
if (plaintext_buffer !== undefined) {
// don't leave a copy of the plaintext in the heap.
bzero(plaintext_buffer, max_plaintext_length + NULL_BYTE_PADDING_LENGTH);
free(plaintext_buffer);
}
}
});
function Utility() {