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Fix issues with corrupt FTN packets

This commit is contained in:
Bryan Ashby 2019-11-22 21:44:24 -07:00
parent 1aa545e254
commit 7ef224be17
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GPG Key ID: B49EB437951D2542
2 changed files with 36 additions and 9 deletions
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40
core/ftn_mail_packet.js
View File

@ -552,13 +552,18 @@ function Packet(options) {
.uint16le('ftn_msg_dest_net')
.uint16le('ftn_attr_flags')
.uint16le('ftn_cost')
// :TODO: use string() for these if https://github.com/keichi/binary-parser/issues/33 is resolved
//
// It would be nice to just string() these, but we want CP437 which requires
// iconv. Another option would be to use a formatter, but until issue 33
// (https://github.com/keichi/binary-parser/issues/33) is fixed, this is cumbersome.
//
.array('modDateTime', {
type : 'uint8',
readUntil : b => 0x00 === b,
length : 20, // FTS-0001.016: 20 bytes
})
.array('toUserName', {
type : 'uint8',
// :TODO: array needs some soft of 'limit' field
readUntil : b => 0x00 === b,
})
.array('fromUserName', {
@ -585,16 +590,35 @@ function Packet(options) {
//
// Convert null terminated arrays to strings
//
// From FTS-0001.016:
// * modDateTime: 20 bytes exactly (see above)
// * toUserName and fromUserName: *max* 36 bytes, aka "up to"; null terminated
// * subject: *max* 72 bytes, aka "up to"; null terminated
// * message: Unbounded & null terminated
//
// For everything above but message, we can get away with assuming CP437
// and probably even just "ascii" for most cases. The message field is
// much more complex so we'll look for encoding kludges, detection, etc.
// later on.
//
if(msgData.modDateTime.length != 20) {
return cb(Errors.Invalid(`FTN packet DateTime field must be 20 bytes (got ${msgData.modDateTime.length})`));
}
if(msgData.toUserName.length > 36) {
return cb(Errors.Invalid(`FTN packet toUserName field must be 36 bytes max (got ${msgData.toUserName.length})`));
}
if(msgData.fromUserName.length > 36) {
return cb(Errors.Invalid(`FTN packet fromUserName field must be 36 bytes max (got ${msgData.fromUserName.length})`));
}
if(msgData.subject.length > 72) {
return cb(Errors.Invalid(`FTN packet subject field must be 72 bytes max (got ${msgData.subject.length})`));
}
// Arrays of CP437 bytes -> String
[ 'modDateTime', 'toUserName', 'fromUserName', 'subject' ].forEach(k => {
msgData[k] = strUtil.stringFromNullTermBuffer(msgData[k], 'CP437');
});
// Technically the following fields have length limits as per fts-0001.016:
// * modDateTime : 20 bytes
// * toUserName : 36 bytes
// * fromUserName : 36 bytes
// * subject : 72 bytes
//
// The message body itself is a special beast as it may
// contain an origin line, kludges, SAUCE in the case

5
util/dump_ftn_packet.js
View File

@ -42,7 +42,10 @@ function main() {
return next(null);
},
() => {
(err) => {
if(err) {
return console.error(`Error processing packet: ${err.message}`);
}
console.info('');
console.info('--- EOF --- ');
console.info('');