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|
/*
Unix SMB/CIFS implementation.
handle unexpected packets
Copyright (C) Andrew Tridgell 2000
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "lib/async_req/async_sock.h"
#include "libsmb/nmblib.h"
static const char *nmbd_socket_dir(void)
{
return lp_parm_const_string(-1, "nmbd", "socket dir",
get_dyn_NMBDSOCKETDIR());
}
struct nb_packet_query {
enum packet_type type;
size_t mailslot_namelen;
int trn_id;
};
struct nb_packet_client;
struct nb_packet_server {
struct tevent_context *ev;
int listen_sock;
int max_clients;
int num_clients;
struct nb_packet_client *clients;
};
struct nb_packet_client {
struct nb_packet_client *prev, *next;
struct nb_packet_server *server;
enum packet_type type;
int trn_id;
char *mailslot_name;
int sock;
struct tevent_req *read_req;
struct tevent_queue *out_queue;
};
static int nb_packet_server_destructor(struct nb_packet_server *s);
static void nb_packet_server_listener(struct tevent_context *ev,
struct tevent_fd *fde,
uint16_t flags,
void *private_data);
NTSTATUS nb_packet_server_create(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
int max_clients,
struct nb_packet_server **presult)
{
struct nb_packet_server *result;
struct tevent_fd *fde;
NTSTATUS status;
result = TALLOC_ZERO_P(mem_ctx, struct nb_packet_server);
if (result == NULL) {
status = NT_STATUS_NO_MEMORY;
goto fail;
}
result->ev = ev;
result->max_clients = max_clients;
result->listen_sock = create_pipe_sock(
nmbd_socket_dir(), "unexpected", 0755);
if (result->listen_sock == -1) {
status = map_nt_error_from_unix(errno);
goto fail;
}
talloc_set_destructor(result, nb_packet_server_destructor);
fde = tevent_add_fd(ev, result, result->listen_sock, TEVENT_FD_READ,
nb_packet_server_listener, result);
if (fde == NULL) {
status = NT_STATUS_NO_MEMORY;
goto fail;
}
*presult = result;
return NT_STATUS_OK;
fail:
TALLOC_FREE(result);
return status;
}
static int nb_packet_server_destructor(struct nb_packet_server *s)
{
if (s->listen_sock != -1) {
close(s->listen_sock);
s->listen_sock = -1;
}
return 0;
}
static int nb_packet_client_destructor(struct nb_packet_client *c);
static ssize_t nb_packet_client_more(uint8_t *buf, size_t buflen,
void *private_data);
static void nb_packet_got_query(struct tevent_req *req);
static void nb_packet_client_read_done(struct tevent_req *req);
static void nb_packet_server_listener(struct tevent_context *ev,
struct tevent_fd *fde,
uint16_t flags,
void *private_data)
{
struct nb_packet_server *server = talloc_get_type_abort(
private_data, struct nb_packet_server);
struct nb_packet_client *client;
struct tevent_req *req;
struct sockaddr_un sunaddr;
socklen_t len;
int sock;
len = sizeof(sunaddr);
sock = accept(server->listen_sock, (struct sockaddr *)(void *)&sunaddr,
&len);
if (sock == -1) {
return;
}
DEBUG(6,("accepted socket %d\n", sock));
client = TALLOC_ZERO_P(server, struct nb_packet_client);
if (client == NULL) {
DEBUG(10, ("talloc failed\n"));
close(sock);
return;
}
client->sock = sock;
client->server = server;
talloc_set_destructor(client, nb_packet_client_destructor);
client->out_queue = tevent_queue_create(
client, "unexpected packet output");
if (client->out_queue == NULL) {
DEBUG(10, ("tevent_queue_create failed\n"));
TALLOC_FREE(client);
return;
}
req = read_packet_send(client, ev, client->sock,
sizeof(struct nb_packet_query),
nb_packet_client_more, NULL);
if (req == NULL) {
DEBUG(10, ("read_packet_send failed\n"));
TALLOC_FREE(client);
return;
}
tevent_req_set_callback(req, nb_packet_got_query, client);
DLIST_ADD(server->clients, client);
server->num_clients += 1;
if (server->num_clients > server->max_clients) {
DEBUG(10, ("Too many clients, dropping oldest\n"));
/*
* no TALLOC_FREE here, don't mess with the list structs
*/
talloc_free(server->clients->prev);
}
}
static ssize_t nb_packet_client_more(uint8_t *buf, size_t buflen,
void *private_data)
{
struct nb_packet_query q;
if (buflen > sizeof(struct nb_packet_query)) {
return 0;
}
/* Take care of alignment */
memcpy(&q, buf, sizeof(q));
if (q.mailslot_namelen > 1024) {
DEBUG(10, ("Got invalid mailslot namelen %d\n",
(int)q.mailslot_namelen));
return -1;
}
return q.mailslot_namelen;
}
static int nb_packet_client_destructor(struct nb_packet_client *c)
{
if (c->sock != -1) {
close(c->sock);
c->sock = -1;
}
DLIST_REMOVE(c->server->clients, c);
c->server->num_clients -= 1;
return 0;
}
static void nb_packet_got_query(struct tevent_req *req)
{
struct nb_packet_client *client = tevent_req_callback_data(
req, struct nb_packet_client);
struct nb_packet_query q;
uint8_t *buf;
ssize_t nread, nwritten;
int err;
char c;
nread = read_packet_recv(req, talloc_tos(), &buf, &err);
TALLOC_FREE(req);
if (nread < sizeof(struct nb_packet_query)) {
DEBUG(10, ("read_packet_recv returned %d (%s)\n",
(int)nread,
(nread == -1) ? strerror(err) : "wrong length"));
TALLOC_FREE(client);
return;
}
/* Take care of alignment */
memcpy(&q, buf, sizeof(q));
if (nread != sizeof(struct nb_packet_query) + q.mailslot_namelen) {
DEBUG(10, ("nb_packet_got_query: Invalid mailslot namelength\n"));
TALLOC_FREE(client);
return;
}
client->trn_id = q.trn_id;
client->type = q.type;
if (q.mailslot_namelen > 0) {
client->mailslot_name = talloc_strndup(
client, (char *)buf + sizeof(q),
q.mailslot_namelen);
if (client->mailslot_name == NULL) {
TALLOC_FREE(client);
return;
}
}
/*
* Yes, this is a blocking write of 1 byte into a unix
* domain socket that has never been written to. Highly
* unlikely that this actually blocks.
*/
c = 0;
nwritten = sys_write(client->sock, &c, sizeof(c));
if (nwritten != sizeof(c)) {
DEBUG(10, ("Could not write success indicator to client: %s\n",
strerror(errno)));
TALLOC_FREE(client);
return;
}
client->read_req = read_packet_send(client, client->server->ev,
client->sock, 1, NULL, NULL);
if (client->read_req == NULL) {
DEBUG(10, ("Could not activate reader for client exit "
"detection\n"));
TALLOC_FREE(client);
return;
}
tevent_req_set_callback(client->read_req, nb_packet_client_read_done,
client);
}
static void nb_packet_client_read_done(struct tevent_req *req)
{
struct nb_packet_client *client = tevent_req_callback_data(
req, struct nb_packet_client);
ssize_t nread;
uint8_t *buf;
int err;
nread = read_packet_recv(req, talloc_tos(), &buf, &err);
TALLOC_FREE(req);
if (nread == 1) {
DEBUG(10, ("Protocol error, received data on write-only "
"unexpected socket: 0x%2.2x\n", (*buf)));
}
TALLOC_FREE(client);
}
static void nb_packet_client_send(struct nb_packet_client *client,
struct packet_struct *p);
void nb_packet_dispatch(struct nb_packet_server *server,
struct packet_struct *p)
{
struct nb_packet_client *c;
uint16_t trn_id;
switch (p->packet_type) {
case NMB_PACKET:
trn_id = p->packet.nmb.header.name_trn_id;
break;
case DGRAM_PACKET:
trn_id = p->packet.dgram.header.dgm_id;
break;
default:
DEBUG(10, ("Got invalid packet type %d\n",
(int)p->packet_type));
return;
}
for (c = server->clients; c != NULL; c = c->next) {
if (c->type != p->packet_type) {
DEBUG(10, ("client expects packet %d, got %d\n",
c->type, p->packet_type));
continue;
}
if (p->packet_type == NMB_PACKET) {
/*
* See if the client specified transaction
* ID. Filter if it did.
*/
if ((c->trn_id != -1) &&
(c->trn_id != trn_id)) {
DEBUG(10, ("client expects trn %d, got %d\n",
c->trn_id, trn_id));
continue;
}
} else {
/*
* See if the client specified a mailslot
* name. Filter if it did.
*/
if ((c->mailslot_name != NULL) &&
!match_mailslot_name(p, c->mailslot_name)) {
continue;
}
}
nb_packet_client_send(c, p);
}
}
struct nb_packet_client_header {
size_t len;
enum packet_type type;
time_t timestamp;
struct in_addr ip;
int port;
};
struct nb_packet_client_state {
struct nb_packet_client *client;
struct iovec iov[2];
struct nb_packet_client_header hdr;
char buf[1024];
};
static void nb_packet_client_send_done(struct tevent_req *req);
static void nb_packet_client_send(struct nb_packet_client *client,
struct packet_struct *p)
{
struct nb_packet_client_state *state;
struct tevent_req *req;
if (tevent_queue_length(client->out_queue) > 10) {
/*
* Skip clients that don't listen anyway, some form of DoS
* protection
*/
return;
}
state = TALLOC_ZERO_P(client, struct nb_packet_client_state);
if (state == NULL) {
DEBUG(10, ("talloc failed\n"));
return;
}
state->client = client;
state->hdr.ip = p->ip;
state->hdr.port = p->port;
state->hdr.timestamp = p->timestamp;
state->hdr.type = p->packet_type;
state->hdr.len = build_packet(state->buf, sizeof(state->buf), p);
state->iov[0].iov_base = (char *)&state->hdr;
state->iov[0].iov_len = sizeof(state->hdr);
state->iov[1].iov_base = state->buf;
state->iov[1].iov_len = state->hdr.len;
TALLOC_FREE(client->read_req);
req = writev_send(client, client->server->ev, client->out_queue,
client->sock, true, state->iov, 2);
if (req == NULL) {
DEBUG(10, ("writev_send failed\n"));
return;
}
tevent_req_set_callback(req, nb_packet_client_send_done, state);
}
static void nb_packet_client_send_done(struct tevent_req *req)
{
struct nb_packet_client_state *state = tevent_req_callback_data(
req, struct nb_packet_client_state);
struct nb_packet_client *client = state->client;
ssize_t nwritten;
int err;
nwritten = writev_recv(req, &err);
TALLOC_FREE(req);
TALLOC_FREE(state);
if (nwritten == -1) {
DEBUG(10, ("writev failed: %s\n", strerror(err)));
TALLOC_FREE(client);
}
if (tevent_queue_length(client->out_queue) == 0) {
client->read_req = read_packet_send(client, client->server->ev,
client->sock, 1,
NULL, NULL);
if (client->read_req == NULL) {
DEBUG(10, ("Could not activate reader for client exit "
"detection\n"));
TALLOC_FREE(client);
return;
}
tevent_req_set_callback(client->read_req,
nb_packet_client_read_done,
client);
}
}
struct nb_packet_reader {
int sock;
};
struct nb_packet_reader_state {
struct tevent_context *ev;
struct sockaddr_un addr;
struct nb_packet_query query;
const char *mailslot_name;
struct iovec iov[2];
char c;
struct nb_packet_reader *reader;
};
static int nb_packet_reader_destructor(struct nb_packet_reader *r);
static void nb_packet_reader_connected(struct tevent_req *subreq);
static void nb_packet_reader_sent_query(struct tevent_req *subreq);
static void nb_packet_reader_got_ack(struct tevent_req *subreq);
struct tevent_req *nb_packet_reader_send(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
enum packet_type type,
int trn_id,
const char *mailslot_name)
{
struct tevent_req *req, *subreq;
struct nb_packet_reader_state *state;
char *path;
req = tevent_req_create(mem_ctx, &state,
struct nb_packet_reader_state);
if (req == NULL) {
return NULL;
}
state->ev = ev;
state->query.trn_id = trn_id;
state->query.type = type;
state->mailslot_name = mailslot_name;
if (mailslot_name != NULL) {
state->query.mailslot_namelen = strlen(mailslot_name);
}
state->reader = TALLOC_ZERO_P(state, struct nb_packet_reader);
if (tevent_req_nomem(state->reader, req)) {
return tevent_req_post(req, ev);
}
path = talloc_asprintf(talloc_tos(), "%s/%s", nmbd_socket_dir(),
"unexpected");
if (tevent_req_nomem(path, req)) {
return tevent_req_post(req, ev);
}
state->addr.sun_family = AF_UNIX;
strlcpy(state->addr.sun_path, path, sizeof(state->addr.sun_path));
TALLOC_FREE(path);
state->reader->sock = socket(AF_UNIX, SOCK_STREAM, 0);
if (state->reader->sock == -1) {
tevent_req_nterror(req, map_nt_error_from_unix(errno));
return tevent_req_post(req, ev);
}
talloc_set_destructor(state->reader, nb_packet_reader_destructor);
subreq = async_connect_send(state, ev, state->reader->sock,
(struct sockaddr *)(void *)&state->addr,
sizeof(state->addr));
if (tevent_req_nomem(subreq, req)) {
return tevent_req_post(req, ev);
}
tevent_req_set_callback(subreq, nb_packet_reader_connected, req);
return req;
}
static int nb_packet_reader_destructor(struct nb_packet_reader *r)
{
if (r->sock != -1) {
close(r->sock);
r->sock = -1;
}
return 0;
}
static void nb_packet_reader_connected(struct tevent_req *subreq)
{
struct tevent_req *req = tevent_req_callback_data(
subreq, struct tevent_req);
struct nb_packet_reader_state *state = tevent_req_data(
req, struct nb_packet_reader_state);
int res, err;
int num_iovecs = 1;
res = async_connect_recv(subreq, &err);
TALLOC_FREE(subreq);
if (res == -1) {
DEBUG(10, ("async_connect failed: %s\n", strerror(err)));
tevent_req_nterror(req, map_nt_error_from_unix(err));
return;
}
state->iov[0].iov_base = (char *)&state->query;
state->iov[0].iov_len = sizeof(state->query);
if (state->mailslot_name != NULL) {
num_iovecs = 2;
state->iov[1].iov_base = discard_const_p(
char, state->mailslot_name);
state->iov[1].iov_len = state->query.mailslot_namelen;
}
subreq = writev_send(state, state->ev, NULL, state->reader->sock,
true, state->iov, num_iovecs);
if (tevent_req_nomem(subreq, req)) {
return;
}
tevent_req_set_callback(subreq, nb_packet_reader_sent_query, req);
}
static void nb_packet_reader_sent_query(struct tevent_req *subreq)
{
struct tevent_req *req = tevent_req_callback_data(
subreq, struct tevent_req);
struct nb_packet_reader_state *state = tevent_req_data(
req, struct nb_packet_reader_state);
ssize_t written;
int err;
written = writev_recv(subreq, &err);
TALLOC_FREE(subreq);
if (written == -1) {
tevent_req_nterror(req, map_nt_error_from_unix(err));
return;
}
if (written != sizeof(state->query) + state->query.mailslot_namelen) {
tevent_req_nterror(req, NT_STATUS_UNEXPECTED_IO_ERROR);
return;
}
subreq = read_packet_send(state, state->ev, state->reader->sock,
sizeof(state->c), NULL, NULL);
if (tevent_req_nomem(subreq, req)) {
return;
}
tevent_req_set_callback(subreq, nb_packet_reader_got_ack, req);
}
static void nb_packet_reader_got_ack(struct tevent_req *subreq)
{
struct tevent_req *req = tevent_req_callback_data(
subreq, struct tevent_req);
struct nb_packet_reader_state *state = tevent_req_data(
req, struct nb_packet_reader_state);
ssize_t nread;
int err;
uint8_t *buf;
nread = read_packet_recv(subreq, state, &buf, &err);
TALLOC_FREE(subreq);
if (nread == -1) {
DEBUG(10, ("read_packet_recv returned %s\n",
strerror(err)));
tevent_req_nterror(req, map_nt_error_from_unix(err));
return;
}
if (nread != sizeof(state->c)) {
DEBUG(10, ("read = %d, expected %d\n", (int)nread,
(int)sizeof(state->c)));
tevent_req_nterror(req, NT_STATUS_UNEXPECTED_IO_ERROR);
return;
}
tevent_req_done(req);
}
NTSTATUS nb_packet_reader_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
struct nb_packet_reader **preader)
{
struct nb_packet_reader_state *state = tevent_req_data(
req, struct nb_packet_reader_state);
NTSTATUS status;
if (tevent_req_is_nterror(req, &status)) {
return status;
}
*preader = talloc_move(mem_ctx, &state->reader);
return NT_STATUS_OK;
}
struct nb_packet_read_state {
struct nb_packet_client_header hdr;
uint8_t *buf;
size_t buflen;
};
static ssize_t nb_packet_read_more(uint8_t *buf, size_t buflen, void *p);
static void nb_packet_read_done(struct tevent_req *subreq);
struct tevent_req *nb_packet_read_send(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
struct nb_packet_reader *reader)
{
struct tevent_req *req, *subreq;
struct nb_packet_read_state *state;
req = tevent_req_create(mem_ctx, &state, struct nb_packet_read_state);
if (req == NULL) {
return NULL;
}
subreq = read_packet_send(state, ev, reader->sock,
sizeof(struct nb_packet_client_header),
nb_packet_read_more, state);
if (tevent_req_nomem(subreq, req)) {
return tevent_req_post(req, ev);
}
tevent_req_set_callback(subreq, nb_packet_read_done, req);
return req;
}
static ssize_t nb_packet_read_more(uint8_t *buf, size_t buflen, void *p)
{
struct nb_packet_read_state *state = talloc_get_type_abort(
p, struct nb_packet_read_state);
if (buflen > sizeof(struct nb_packet_client_header)) {
/*
* Been here, done
*/
return 0;
}
memcpy(&state->hdr, buf, sizeof(struct nb_packet_client_header));
return state->hdr.len;
}
static void nb_packet_read_done(struct tevent_req *subreq)
{
struct tevent_req *req = tevent_req_callback_data(
subreq, struct tevent_req);
struct nb_packet_read_state *state = tevent_req_data(
req, struct nb_packet_read_state);
ssize_t nread;
int err;
nread = read_packet_recv(subreq, state, &state->buf, &err);
if (nread == -1) {
tevent_req_nterror(req, map_nt_error_from_unix(err));
return;
}
state->buflen = nread;
tevent_req_done(req);
}
NTSTATUS nb_packet_read_recv(struct tevent_req *req,
struct packet_struct **ppacket)
{
struct nb_packet_read_state *state = tevent_req_data(
req, struct nb_packet_read_state);
struct nb_packet_client_header hdr;
struct packet_struct *packet;
NTSTATUS status;
if (tevent_req_is_nterror(req, &status)) {
return status;
}
memcpy(&hdr, state->buf, sizeof(hdr));
packet = parse_packet(
(char *)state->buf + sizeof(struct nb_packet_client_header),
state->buflen - sizeof(struct nb_packet_client_header),
state->hdr.type, state->hdr.ip, state->hdr.port);
if (packet == NULL) {
return NT_STATUS_INVALID_NETWORK_RESPONSE;
}
*ppacket = packet;
return NT_STATUS_OK;
}
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