diff options
| -rw-r--r-- | source3/libsmb/async_smb.c | 534 |
1 files changed, 534 insertions, 0 deletions
diff --git a/source3/libsmb/async_smb.c b/source3/libsmb/async_smb.c index e36e514a16..e764147432 100644 --- a/source3/libsmb/async_smb.c +++ b/source3/libsmb/async_smb.c @@ -135,6 +135,540 @@ static int cli_request_destructor(struct cli_request *req) return 0; } +#if 0 + +/** + * Is the SMB command able to hold an AND_X successor + * @param[in] cmd The SMB command in question + * @retval Can we add a chained request after "cmd"? + */ + +static bool is_andx_req(uint8_t cmd) +{ + switch (cmd) { + case SMBtconX: + case SMBlockingX: + case SMBopenX: + case SMBreadX: + case SMBwriteX: + case SMBsesssetupX: + case SMBulogoffX: + case SMBntcreateX: + return true; + break; + default: + break; + } + + return false; +} + +/** + * @brief Find the smb_cmd offset of the last command pushed + * @param[in] buf The buffer we're building up + * @retval Where can we put our next andx cmd? + * + * While chaining requests, the "next" request we're looking at needs to put + * its SMB_Command before the data the previous request already built up added + * to the chain. Find the offset to the place where we have to put our cmd. + */ + +static bool find_andx_cmd_ofs(char *buf, size_t *pofs) +{ + uint8_t cmd; + size_t ofs; + + cmd = CVAL(buf, smb_com); + + SMB_ASSERT(is_andx_req(cmd)); + + ofs = smb_vwv0; + + while (CVAL(buf, ofs) != 0xff) { + + if (!is_andx_req(CVAL(buf, ofs))) { + return false; + } + + /* + * ofs is from start of smb header, so add the 4 length + * bytes. The next cmd is right after the wct field. + */ + ofs = SVAL(buf, ofs+2) + 4 + 1; + + SMB_ASSERT(ofs+4 < talloc_get_size(buf)); + } + + *pofs = ofs; + return true; +} + +/** + * @brief Destroy an async_req that is the visible part of a cli_request + * @param[in] req The request to kill + * @retval Return 0 to make talloc happy + * + * This destructor is a bit tricky: Because a cli_request can host more than + * one async_req for chained requests, we need to make sure that the + * "cli_request" that we were part of is correctly destroyed at the right + * time. This is done by NULLing out ourself from the "async" member of our + * "cli_request". If there is none left, then also TALLOC_FREE() the + * cli_request, which was a talloc child of the client connection cli_state. + */ + +static int cli_async_req_destructor(struct async_req *req) +{ + struct cli_request *cli_req = cli_request_get(req); + int i, pending; + bool found = false; + + pending = 0; + + for (i=0; i<cli_req->num_async; i++) { + if (cli_req->async[i] == req) { + cli_req->async[i] = NULL; + found = true; + } + if (cli_req->async[i] != NULL) { + pending += 1; + } + } + + SMB_ASSERT(found); + + if (pending == 0) { + TALLOC_FREE(cli_req); + } + + return 0; +} + +/** + * @brief Chain up a request + * @param[in] mem_ctx The TALLOC_CTX for the result + * @param[in] ev The event context that will call us back + * @param[in] cli The cli_state we queue the request up for + * @param[in] smb_command The command that we want to issue + * @param[in] additional_flags open_and_x wants to add oplock header flags + * @param[in] wct How many words? + * @param[in] vwv The words, already in network order + * @param[in] num_bytes How many bytes? + * @param[in] bytes The data the request ships + * + * cli_request_chain() is the core of the SMB request marshalling routine. It + * will create a new async_req structure in the cli->chain_accumulator->async + * array and marshall the smb_cmd, the vwv array and the bytes into + * cli->chain_accumulator->outbuf. + */ + +static struct async_req *cli_request_chain(TALLOC_CTX *mem_ctx, + struct event_context *ev, + struct cli_state *cli, + uint8_t smb_command, + uint8_t additional_flags, + uint8_t wct, const uint16_t *vwv, + uint16_t num_bytes, + const uint8_t *bytes) +{ + struct async_req **tmp_reqs; + char *tmp_buf; + struct cli_request *req; + size_t old_size, new_size; + size_t ofs; + + req = cli->chain_accumulator; + + tmp_reqs = TALLOC_REALLOC_ARRAY(req, req->async, struct async_req *, + req->num_async + 1); + if (tmp_reqs == NULL) { + DEBUG(0, ("talloc failed\n")); + return NULL; + } + req->async = tmp_reqs; + req->num_async += 1; + + req->async[req->num_async-1] = async_req_new(mem_ctx, ev); + if (req->async[req->num_async-1] == NULL) { + DEBUG(0, ("async_req_new failed\n")); + req->num_async -= 1; + return NULL; + } + req->async[req->num_async-1]->private_data = req; + req->async[req->num_async-1]->print = cli_request_print; + talloc_set_destructor(req->async[req->num_async-1], + cli_async_req_destructor); + + old_size = talloc_get_size(req->outbuf); + + /* + * We need space for the wct field, the words, the byte count field + * and the bytes themselves. + */ + new_size = old_size + 1 + wct * sizeof(uint16_t) + 2 + num_bytes; + + if (new_size > 0xffff) { + DEBUG(1, ("cli_request_chain: %u bytes won't fit\n", + (unsigned)new_size)); + goto fail; + } + + tmp_buf = TALLOC_REALLOC_ARRAY(NULL, req->outbuf, char, new_size); + if (tmp_buf == NULL) { + DEBUG(0, ("talloc failed\n")); + goto fail; + } + req->outbuf = tmp_buf; + + if (old_size == smb_wct) { + SCVAL(req->outbuf, smb_com, smb_command); + } else { + size_t andx_cmd_ofs; + if (!find_andx_cmd_ofs(req->outbuf, &andx_cmd_ofs)) { + DEBUG(1, ("invalid command chain\n")); + goto fail; + } + SCVAL(req->outbuf, andx_cmd_ofs, smb_command); + SSVAL(req->outbuf, andx_cmd_ofs + 2, old_size - 4); + } + + ofs = old_size; + + SCVAL(req->outbuf, ofs, wct); + ofs += 1; + + memcpy(req->outbuf + ofs, vwv, sizeof(uint16_t) * wct); + ofs += sizeof(uint16_t) * wct; + + SSVAL(req->outbuf, ofs, num_bytes); + ofs += sizeof(uint16_t); + + memcpy(req->outbuf + ofs, bytes, num_bytes); + + return req->async[req->num_async-1]; + + fail: + TALLOC_FREE(req->async[req->num_async-1]); + req->num_async -= 1; + return NULL; +} + +/** + * @brief prepare a cli_state to accept a chain of requests + * @param[in] cli The cli_state we want to queue up in + * @param[in] ev The event_context that will call us back for the socket + * @param[in] size_hint How many bytes are expected, just an optimization + * @retval Did we have enough memory? + * + * cli_chain_cork() sets up a new cli_request in cli->chain_accumulator. If + * cli is used in an async fashion, i.e. if we have outstanding requests, then + * we do not have to create a fd event. If cli is used only with the sync + * helpers, we need to create the fd_event here. + * + * If you want to issue a chained request to the server, do a + * cli_chain_cork(), then do you cli_open_send(), cli_read_and_x_send(), + * cli_close_send() and so on. The async requests that come out of + * cli_xxx_send() are normal async requests with the difference that they + * won't be shipped individually. But the event_context will still trigger the + * req->async.fn to be called on every single request. + * + * You have to take care yourself that you only issue chainable requests in + * the middle of the chain. + */ + +bool cli_chain_cork(struct cli_state *cli, struct event_context *ev, + size_t size_hint) +{ + struct cli_request *req = NULL; + + SMB_ASSERT(cli->chain_accumulator == NULL); + + if (cli->fd_event == NULL) { + SMB_ASSERT(cli->outstanding_requests == NULL); + cli->fd_event = event_add_fd(ev, cli, cli->fd, + EVENT_FD_READ, + cli_state_handler, cli); + if (cli->fd_event == NULL) { + return false; + } + } + + req = talloc(cli, struct cli_request); + if (req == NULL) { + goto fail; + } + req->cli = cli; + + if (size_hint == 0) { + size_hint = 100; + } + req->outbuf = talloc_array(req, char, smb_wct + size_hint); + if (req->outbuf == NULL) { + goto fail; + } + req->outbuf = TALLOC_REALLOC_ARRAY(NULL, req->outbuf, char, smb_wct); + + req->num_async = 0; + req->async = NULL; + + req->enc_state = NULL; + + SSVAL(req->outbuf, smb_tid, cli->cnum); + cli_setup_packet_buf(cli, req->outbuf); + + req->mid = cli_new_mid(cli); + SSVAL(req->outbuf, smb_mid, req->mid); + + cli->chain_accumulator = req; + + DEBUG(10, ("cli_chain_cork: mid=%d\n", req->mid)); + + return true; + fail: + TALLOC_FREE(req); + if (cli->outstanding_requests == NULL) { + TALLOC_FREE(cli->fd_event); + } + return false; +} + +/** + * Ship a request queued up via cli_request_chain() + * @param[in] cl The connection + */ + +void cli_chain_uncork(struct cli_state *cli) +{ + struct cli_request *req = cli->chain_accumulator; + + SMB_ASSERT(req != NULL); + + DLIST_ADD_END(cli->outstanding_requests, req, struct cli_request *); + talloc_set_destructor(req, cli_request_destructor); + + cli->chain_accumulator = NULL; + + smb_setlen(req->outbuf, talloc_get_size(req->outbuf) - 4); + + cli_calculate_sign_mac(cli, req->outbuf); + + if (cli_encryption_on(cli)) { + NTSTATUS status; + char *enc_buf; + + status = cli_encrypt_message(cli, req->outbuf, &enc_buf); + if (!NT_STATUS_IS_OK(status)) { + DEBUG(0, ("Error in encrypting client message. " + "Error %s\n", nt_errstr(status))); + TALLOC_FREE(req); + return; + } + req->outbuf = enc_buf; + req->enc_state = cli->trans_enc_state; + } + + req->sent = 0; + + event_fd_set_writeable(cli->fd_event); +} + +/** + * @brief Send a request to the server + * @param[in] mem_ctx The TALLOC_CTX for the result + * @param[in] ev The event context that will call us back + * @param[in] cli The cli_state we queue the request up for + * @param[in] smb_command The command that we want to issue + * @param[in] additional_flags open_and_x wants to add oplock header flags + * @param[in] wct How many words? + * @param[in] vwv The words, already in network order + * @param[in] num_bytes How many bytes? + * @param[in] bytes The data the request ships + * + * This is the generic routine to be used by the cli_xxx_send routines. + */ + +struct async_req *cli_request_send(TALLOC_CTX *mem_ctx, + struct event_context *ev, + struct cli_state *cli, + uint8_t smb_command, + uint8_t additional_flags, + uint8_t wct, const uint16_t *vwv, + uint16_t num_bytes, const uint8_t *bytes) +{ + struct async_req *result; + bool uncork = false; + + if (cli->chain_accumulator == NULL) { + if (!cli_chain_cork(cli, ev, + wct * sizeof(uint16_t) + num_bytes + 3)) { + DEBUG(1, ("cli_chain_cork failed\n")); + return NULL; + } + uncork = true; + } + + result = cli_request_chain(mem_ctx, ev, cli, smb_command, + additional_flags, wct, vwv, + num_bytes, bytes); + + if (result == NULL) { + DEBUG(1, ("cli_request_chain failed\n")); + } + + if (uncork) { + cli_chain_uncork(cli); + } + + return result; +} + +/** + * Figure out if there is an andx command behind the current one + * @param[in] buf The smb buffer to look at + * @param[in] ofs The offset to the wct field that is followed by the cmd + * @retval Is there a command following? + */ + +static bool have_andx_command(const char *buf, uint16_t ofs) +{ + uint8_t wct; + size_t buflen = talloc_get_size(buf); + + if ((ofs == buflen-1) || (ofs == buflen)) { + return false; + } + + wct = CVAL(buf, ofs); + if (wct < 2) { + /* + * Not enough space for the command and a following pointer + */ + return false; + } + return (CVAL(buf, ofs+1) != 0xff); +} + +/** + * @brief Pull reply data out of a request + * @param[in] req The request that we just received a reply for + * @param[out] pwct How many words did the server send? + * @param[out] pvwv The words themselves + * @param[out] pnum_bytes How many bytes did the server send? + * @param[out] pbytes The bytes themselves + * @retval Was the reply formally correct? + */ + +NTSTATUS cli_pull_reply(struct async_req *req, + uint8_t *pwct, uint16_t **pvwv, + uint16_t *pnum_bytes, uint8_t **pbytes) +{ + struct cli_request *cli_req = cli_request_get(req); + uint8_t wct, cmd; + uint16_t num_bytes; + size_t wct_ofs, bytes_offset; + int i, j; + NTSTATUS status; + + for (i = 0; i < cli_req->num_async; i++) { + if (req == cli_req->async[i]) { + break; + } + } + + if (i == cli_req->num_async) { + cli_set_error(cli_req->cli, NT_STATUS_INVALID_PARAMETER); + return NT_STATUS_INVALID_PARAMETER; + } + + /** + * The status we pull here is only relevant for the last reply in the + * chain. + */ + + status = cli_pull_error(cli_req->inbuf); + + if (i == 0) { + if (NT_STATUS_IS_ERR(status) + && !have_andx_command(cli_req->inbuf, smb_wct)) { + cli_set_error(cli_req->cli, status); + return status; + } + wct_ofs = smb_wct; + goto done; + } + + cmd = CVAL(cli_req->inbuf, smb_com); + wct_ofs = smb_wct; + + for (j = 0; j < i; j++) { + if (j < i-1) { + if (cmd == 0xff) { + return NT_STATUS_REQUEST_ABORTED; + } + if (!is_andx_req(cmd)) { + return NT_STATUS_INVALID_NETWORK_RESPONSE; + } + } + + if (!have_andx_command(cli_req->inbuf, wct_ofs)) { + /* + * This request was not completed because a previous + * request in the chain had received an error. + */ + return NT_STATUS_REQUEST_ABORTED; + } + + wct_ofs = SVAL(cli_req->inbuf, wct_ofs + 3); + + /* + * Skip the all-present length field. No overflow, we've just + * put a 16-bit value into a size_t. + */ + wct_ofs += 4; + + if (wct_ofs+2 > talloc_get_size(cli_req->inbuf)) { + return NT_STATUS_INVALID_NETWORK_RESPONSE; + } + + cmd = CVAL(cli_req->inbuf, wct_ofs + 1); + } + + if (!have_andx_command(cli_req->inbuf, wct_ofs) + && NT_STATUS_IS_ERR(status)) { + /* + * The last command takes the error code. All further commands + * down the requested chain will get a + * NT_STATUS_REQUEST_ABORTED. + */ + return status; + } + + done: + wct = CVAL(cli_req->inbuf, wct_ofs); + + bytes_offset = wct_ofs + 1 + wct * sizeof(uint16_t); + num_bytes = SVAL(cli_req->inbuf, bytes_offset); + + /* + * wct_ofs is a 16-bit value plus 4, wct is a 8-bit value, num_bytes + * is a 16-bit value. So bytes_offset being size_t should be far from + * wrapping. + */ + + if ((bytes_offset + 2 > talloc_get_size(cli_req->inbuf)) + || (bytes_offset > 0xffff)) { + return NT_STATUS_INVALID_NETWORK_RESPONSE; + } + + *pwct = wct; + *pvwv = (uint16_t *)(cli_req->inbuf + wct_ofs + 1); + *pnum_bytes = num_bytes; + *pbytes = (uint8_t *)cli_req->inbuf + bytes_offset + 2; + + return NT_STATUS_OK; +} + +#endif + /* * Create a fresh async smb request */ |