static void _generic_check_pbkdf(const char *alg, const struct data *data)
{
int ret;
size_t passwordlen = strlen(data->password);
size_t saltlen = strlen(data->salt);
unsigned char salt[128];
unsigned char expected[128];
unsigned char result[128];
hex_str_to_bytes(data->salt, salt);
hex_str_to_bytes(data->expected, expected);
ret = cfe_pbkdf_derive(alg, data->rounds, data->password, passwordlen,
salt, saltlen / 2, result, data->keysize);
assert_int_equal(ret, 0);
ret = memcmp(result, expected, data->keysize);
assert_int_equal(ret, 0);
}
/* Transfers happen in response to broadcasts, they are always TCP and are
* used to send the file to the port mentioned in the broadcast. There are
* 2 types of transfers: Pushes, which are direct responses to searches,
* in which the peer that has the file connects to the peer that doesn't and
* sends it, then disconnects. The other type of transfer is a pull, where
* the peer that doesn't have the file connects to the peer that does and
* requests it be sent.
*
* Pulls have a file request which identifies the desired file,
* while pushes simply send the file. In practice this works because every
* file the implementation sends searches for is on a different TCP port
* on the searcher's machine. */
static int
dissect_ldss_transfer (tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
{
conversation_t *transfer_conv;
ldss_transfer_info_t *transfer_info;
struct tcpinfo *transfer_tcpinfo;
proto_tree *ti, *line_tree = NULL, *ldss_tree = NULL;
nstime_t broadcast_response_time;
/* Reject the packet if data is NULL */
if (data == NULL)
return 0;
transfer_tcpinfo = (struct tcpinfo *)data;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "LDSS");
/* Look for the transfer conversation; this was created during
* earlier broadcast dissection (see prepare_ldss_transfer_conv) */
transfer_conv = find_conversation (pinfo->num, &pinfo->src, &pinfo->dst,
PT_TCP, pinfo->srcport, pinfo->destport, 0);
transfer_info = (ldss_transfer_info_t *)conversation_get_proto_data(transfer_conv, proto_ldss);
/* For a pull, the first packet in the TCP connection is the file request.
* First packet is identified by relative seq/ack numbers of 1.
* File request only appears on a pull (triggered by an offer - see above
* about broadcasts) */
if (transfer_tcpinfo->seq == 1 &&
transfer_tcpinfo->lastackseq == 1 &&
transfer_info->broadcast->message_id == MESSAGE_ID_WILLSEND) {
/* LDSS pull transfers look a lot like HTTP.
* Sample request:
* md5:01234567890123...
* Size: 2550
* Start: 0
* Compression: 0
* (remote end sends the file identified by the digest) */
guint offset = 0;
gboolean already_dissected = TRUE;
col_set_str(pinfo->cinfo, COL_INFO, "LDSS File Transfer (Requesting file - pull)");
if (highest_num_seen == 0 ||
highest_num_seen < pinfo->num) {
already_dissected = FALSE;
transfer_info->req = wmem_new0(wmem_file_scope(), ldss_file_request_t);
transfer_info->req->file = wmem_new0(wmem_file_scope(), ldss_file_t);
highest_num_seen = pinfo->num;
}
if (tree) {
ti = proto_tree_add_item(tree, proto_ldss,
tvb, 0, tvb_reported_length(tvb), ENC_NA);
ldss_tree = proto_item_add_subtree(ti, ett_ldss_transfer);
}
/* Populate digest data into the file struct in the request */
transfer_info->file = transfer_info->req->file;
/* Grab each line from the packet, there should be 4 but lets
* not walk off the end looking for more. */
while (tvb_offset_exists(tvb, offset)) {
gint next_offset;
const guint8 *line;
int linelen;
gboolean is_digest_line;
guint digest_type_len;
linelen = tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
/* Include new-line in line */
line = (guint8 *)tvb_memdup(NULL, tvb, offset, linelen+1); /* XXX - memory leak? */
line_tree = proto_tree_add_subtree(ldss_tree, tvb, offset, linelen,
ett_ldss_transfer_req, NULL,
tvb_format_text(tvb, offset, next_offset-offset));
/* Reduce code duplication processing digest lines.
* There are too many locals to pass to a function - the signature
* looked pretty ugly when I tried! */
is_digest_line = FALSE;
if (strncmp(line,"md5:",4)==0) {
is_digest_line = TRUE;
digest_type_len = 4;
transfer_info->file->digest_type = DIGEST_TYPE_MD5;
}
else if (strncmp(line, "sha1:", 5)==0) {
is_digest_line = TRUE;
digest_type_len = 5;
transfer_info->file->digest_type = DIGEST_TYPE_SHA1;
}
else if (strncmp(line, "sha256:", 7)==0) {
is_digest_line = TRUE;
digest_type_len = 7;
transfer_info->file->digest_type = DIGEST_TYPE_SHA256;
}
else if (strncmp(line, "unknown:", 8)==0) {
is_digest_line = TRUE;
digest_type_len = 8;
transfer_info->file->digest_type = DIGEST_TYPE_UNKNOWN;
}
else if (strncmp(line, "Size: ", 6)==0) {
/* Sample size line:
* Size: 2550\n */
transfer_info->req->size = g_ascii_strtoull(line+6, NULL, 10);
if (tree) {
ti = proto_tree_add_uint64(line_tree, hf_ldss_size,
tvb, offset+6, linelen-6, transfer_info->req->size);
PROTO_ITEM_SET_GENERATED(ti);
}
}
else if (strncmp(line, "Start: ", 7)==0) {
/* Sample offset line:
* Start: 0\n */
transfer_info->req->offset = g_ascii_strtoull(line+7, NULL, 10);
if (tree) {
ti = proto_tree_add_uint64(line_tree, hf_ldss_offset,
tvb, offset+7, linelen-7, transfer_info->req->offset);
PROTO_ITEM_SET_GENERATED(ti);
}
}
else if (strncmp(line, "Compression: ", 13)==0) {
/* Sample compression line:
* Compression: 0\n */
transfer_info->req->compression = (gint8)strtol(line+13, NULL, 10); /* XXX - bad cast */
if (tree) {
ti = proto_tree_add_uint(line_tree, hf_ldss_compression,
tvb, offset+13, linelen-13, transfer_info->req->compression);
PROTO_ITEM_SET_GENERATED(ti);
}
}
else {
proto_tree_add_expert(line_tree, pinfo, &ei_ldss_unrecognized_line, tvb, offset, linelen);
}
if (is_digest_line) {
/* Sample digest-type/digest line:
* md5:0123456789ABCDEF\n */
if (!already_dissected) {
GByteArray *digest_bytes;
digest_bytes = g_byte_array_new();
hex_str_to_bytes(
tvb_get_ptr(tvb, offset+digest_type_len, linelen-digest_type_len),
digest_bytes, FALSE);
if(digest_bytes->len >= DIGEST_LEN)
digest_bytes->len = (DIGEST_LEN-1);
/* Ensure the digest is zero-padded */
transfer_info->file->digest = (guint8 *)wmem_alloc0(wmem_file_scope(), DIGEST_LEN);
memcpy(transfer_info->file->digest, digest_bytes->data, digest_bytes->len);
g_byte_array_free(digest_bytes, TRUE);
}
if (tree) {
proto_item *tii = NULL;
tii = proto_tree_add_uint(line_tree, hf_ldss_digest_type,
tvb, offset, digest_type_len, transfer_info->file->digest_type);
PROTO_ITEM_SET_GENERATED(tii);
tii = proto_tree_add_bytes(line_tree, hf_ldss_digest,
tvb, offset+digest_type_len, MIN(linelen-digest_type_len, DIGEST_LEN),
transfer_info->file->digest);
PROTO_ITEM_SET_GENERATED(tii);
}
}
offset = next_offset;
}
/* Link forwards to the response for this pull. */
if (tree && transfer_info->resp_num != 0) {
ti = proto_tree_add_uint(ldss_tree, hf_ldss_response_in,
tvb, 0, 0, transfer_info->resp_num);
PROTO_ITEM_SET_GENERATED(ti);
}
transfer_info->req->num = pinfo->num;
transfer_info->req->ts = pinfo->abs_ts;
}
/* Remaining packets are the file response */
else {
guint64 size;
guint64 offset;
guint8 compression;
/* size, digest, compression come from the file request for a pull but
* they come from the broadcast for a push. Pushes don't bother
* with a file request - they just send the data. We have to get file
* info from the offer broadcast which triggered this transfer.
* If we cannot find the file request, default to the broadcast. */
if (transfer_info->broadcast->message_id == MESSAGE_ID_WILLSEND &&
transfer_info->req != NULL) {
transfer_info->file = transfer_info->req->file;
size = transfer_info->req->size;
offset = transfer_info->req->offset;
compression = transfer_info->req->compression;
}
else {
transfer_info->file = transfer_info->broadcast->file;
size = transfer_info->broadcast->size;
offset = transfer_info->broadcast->offset;
compression = transfer_info->broadcast->compression;
}
/* Remaining data in this TCP connection is all file data.
* Always desegment if the size is 0 (ie. unknown)
*/
if (pinfo->can_desegment) {
if (size == 0 || tvb_captured_length(tvb) < size) {
pinfo->desegment_offset = 0;
pinfo->desegment_len = DESEGMENT_UNTIL_FIN;
return 0;
}
}
/* OK. Now we have the whole file that was transferred. */
transfer_info->resp_num = pinfo->num;
transfer_info->resp_ts = pinfo->abs_ts;
col_add_fstr(pinfo->cinfo, COL_INFO, "LDSS File Transfer (Sending file - %s)",
transfer_info->broadcast->message_id == MESSAGE_ID_WILLSEND
? "pull"
: "push");
if (tree) {
ti = proto_tree_add_item(tree, proto_ldss,
tvb, 0, tvb_reported_length(tvb), ENC_NA);
ldss_tree = proto_item_add_subtree(ti, ett_ldss_transfer);
proto_tree_add_bytes_format(ldss_tree, hf_ldss_file_data,
tvb, 0, tvb_captured_length(tvb), NULL,
compression == COMPRESSION_GZIP
? "Gzip compressed data: %d bytes"
: "File data: %d bytes",
tvb_captured_length(tvb));
#ifdef HAVE_ZLIB
/* Be nice and uncompress the file data. */
if (compression == COMPRESSION_GZIP) {
tvbuff_t *uncomp_tvb;
uncomp_tvb = tvb_child_uncompress(tvb, tvb, 0, tvb_captured_length(tvb));
if (uncomp_tvb != NULL) {
/* XXX: Maybe not a good idea to add a data_source for
what may very well be a large buffer since then
the full uncompressed buffer will be shown in a tab
in the hex bytes pane ?
However, if we don't, bytes in an unrelated tab will
be highlighted.
*/
add_new_data_source(pinfo, uncomp_tvb, "Uncompressed Data");
proto_tree_add_bytes_format_value(ldss_tree, hf_ldss_file_data,
uncomp_tvb, 0, tvb_captured_length(uncomp_tvb),
NULL, "Uncompressed data: %d bytes",
tvb_captured_length(uncomp_tvb));
}
}
#endif
ti = proto_tree_add_uint(ldss_tree, hf_ldss_digest_type,
tvb, 0, 0, transfer_info->file->digest_type);
PROTO_ITEM_SET_GENERATED(ti);
if (transfer_info->file->digest != NULL) {
/* This is ugly. You can't add bytes of nonzero length and have
* filtering work correctly unless you give a valid location in
* the packet. This hack pretends the first 32 bytes of the packet
* are the digest, which they aren't: they're actually the first 32
* bytes of the file that was sent. */
ti = proto_tree_add_bytes(ldss_tree, hf_ldss_digest,
tvb, 0, DIGEST_LEN, transfer_info->file->digest);
}
PROTO_ITEM_SET_GENERATED(ti);
ti = proto_tree_add_uint64(ldss_tree, hf_ldss_size,
tvb, 0, 0, size);
PROTO_ITEM_SET_GENERATED(ti);
ti = proto_tree_add_uint64(ldss_tree, hf_ldss_offset,
tvb, 0, 0, offset);
PROTO_ITEM_SET_GENERATED(ti);
ti = proto_tree_add_uint(ldss_tree, hf_ldss_compression,
tvb, 0, 0, compression);
PROTO_ITEM_SET_GENERATED(ti);
/* Link to the request for a pull. */
if (transfer_info->broadcast->message_id == MESSAGE_ID_WILLSEND &&
transfer_info->req != NULL &&
transfer_info->req->num != 0) {
ti = proto_tree_add_uint(ldss_tree, hf_ldss_response_to,
tvb, 0, 0, transfer_info->req->num);
PROTO_ITEM_SET_GENERATED(ti);
}
}
}
/* Print the pull response time */
if (transfer_info->broadcast->message_id == MESSAGE_ID_WILLSEND &&
transfer_info->req != NULL &&
transfer_info->resp_num != 0) {
nstime_t pull_response_time;
nstime_delta(&pull_response_time, &transfer_info->resp_ts,
&transfer_info->req->ts);
ti = proto_tree_add_time(ldss_tree, hf_ldss_transfer_response_time,
tvb, 0, 0, &pull_response_time);
PROTO_ITEM_SET_GENERATED(ti);
}
/* Link the transfer back to the initiating broadcast. Response time is
* calculated as the time from broadcast to completed transfer. */
ti = proto_tree_add_uint(ldss_tree, hf_ldss_initiated_by,
tvb, 0, 0, transfer_info->broadcast->num);
PROTO_ITEM_SET_GENERATED(ti);
if (transfer_info->resp_num != 0) {
nstime_delta(&broadcast_response_time, &transfer_info->resp_ts,
&transfer_info->broadcast->ts);
ti = proto_tree_add_time(ldss_tree, hf_ldss_transfer_completed_in,
tvb, 0, 0, &broadcast_response_time);
PROTO_ITEM_SET_GENERATED(ti);
}
/* This conv got its addr2/port2 set by the TCP dissector because a TCP
* connection was established. Make a new one to handle future connections
* to the addr/port mentioned in the broadcast, because that socket is
* still open. */
if (transfer_tcpinfo->seq == 1 &&
transfer_tcpinfo->lastackseq == 1) {
prepare_ldss_transfer_conv(transfer_info->broadcast);
}
return tvb_captured_length(tvb);
}
