/* Unix SMB/CIFS implementation. Core SMB2 server Copyright (C) Stefan Metzmacher 2009 Copyright (C) Jeremy Allison 2010 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 . */ #include "includes.h" #include "locking/share_mode_lock.h" #include "smbd/smbd.h" #include "smbd/globals.h" #include "../libcli/smb/smb_common.h" #include "../lib/util/tevent_ntstatus.h" #include "lib/dbwrap/dbwrap_watch.h" #include "librpc/gen_ndr/open_files.h" #include "messages.h" #undef DBGC_CLASS #define DBGC_CLASS DBGC_SMB2 struct smbd_smb2_lock_element { uint64_t offset; uint64_t length; uint32_t flags; }; struct smbd_smb2_lock_state { struct tevent_context *ev; struct smbd_smb2_request *smb2req; struct smb_request *smb1req; struct files_struct *fsp; bool blocking; uint32_t polling_msecs; uint32_t retry_msecs; uint16_t lock_count; struct smbd_lock_element *locks; uint8_t lock_sequence_value; uint8_t *lock_sequence_element; }; static struct tevent_req *smbd_smb2_lock_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev, struct smbd_smb2_request *smb2req, struct files_struct *in_fsp, uint32_t in_lock_sequence, uint16_t in_lock_count, struct smbd_smb2_lock_element *in_locks); static NTSTATUS smbd_smb2_lock_recv(struct tevent_req *req); static void smbd_smb2_request_lock_done(struct tevent_req *subreq); NTSTATUS smbd_smb2_request_process_lock(struct smbd_smb2_request *req) { const uint8_t *inbody; uint16_t in_lock_count; uint32_t in_lock_sequence; uint64_t in_file_id_persistent; uint64_t in_file_id_volatile; struct files_struct *in_fsp; struct smbd_smb2_lock_element *in_locks; struct tevent_req *subreq; const uint8_t *lock_buffer; uint16_t l; NTSTATUS status; status = smbd_smb2_request_verify_sizes(req, 0x30); if (!NT_STATUS_IS_OK(status)) { return smbd_smb2_request_error(req, status); } inbody = SMBD_SMB2_IN_BODY_PTR(req); in_lock_count = CVAL(inbody, 0x02); if (req->xconn->protocol >= PROTOCOL_SMB2_10) { in_lock_sequence = IVAL(inbody, 0x04); } else { /* 0x04 - 4 bytes reserved */ in_lock_sequence = 0; } in_file_id_persistent = BVAL(inbody, 0x08); in_file_id_volatile = BVAL(inbody, 0x10); if (in_lock_count < 1) { return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER); } if (((in_lock_count - 1) * 0x18) > SMBD_SMB2_IN_DYN_LEN(req)) { return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER); } in_locks = talloc_array(req, struct smbd_smb2_lock_element, in_lock_count); if (in_locks == NULL) { return smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY); } l = 0; lock_buffer = inbody + 0x18; in_locks[l].offset = BVAL(lock_buffer, 0x00); in_locks[l].length = BVAL(lock_buffer, 0x08); in_locks[l].flags = IVAL(lock_buffer, 0x10); /* 0x14 - 4 reserved bytes */ status = req->session->status; if (NT_STATUS_EQUAL(status, NT_STATUS_NETWORK_SESSION_EXPIRED)) { /* * We need to catch NT_STATUS_NETWORK_SESSION_EXPIRED * for lock requests only. * * Unlock requests still need to be processed! * * This means smbd_smb2_request_check_session() * can't handle the difference and always * allows SMB2_OP_LOCK. */ if (in_locks[0].flags != SMB2_LOCK_FLAG_UNLOCK) { return smbd_smb2_request_error(req, status); } } lock_buffer = SMBD_SMB2_IN_DYN_PTR(req); for (l=1; l < in_lock_count; l++) { in_locks[l].offset = BVAL(lock_buffer, 0x00); in_locks[l].length = BVAL(lock_buffer, 0x08); in_locks[l].flags = IVAL(lock_buffer, 0x10); /* 0x14 - 4 reserved bytes */ lock_buffer += 0x18; } in_fsp = file_fsp_smb2(req, in_file_id_persistent, in_file_id_volatile); if (in_fsp == NULL) { return smbd_smb2_request_error(req, NT_STATUS_FILE_CLOSED); } subreq = smbd_smb2_lock_send(req, req->sconn->ev_ctx, req, in_fsp, in_lock_sequence, in_lock_count, in_locks); if (subreq == NULL) { return smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY); } tevent_req_set_callback(subreq, smbd_smb2_request_lock_done, req); return smbd_smb2_request_pending_queue(req, subreq, 500); } static void smbd_smb2_request_lock_done(struct tevent_req *subreq) { struct smbd_smb2_request *smb2req = tevent_req_callback_data(subreq, struct smbd_smb2_request); DATA_BLOB outbody; NTSTATUS status; NTSTATUS error; /* transport error */ status = smbd_smb2_lock_recv(subreq); TALLOC_FREE(subreq); if (!NT_STATUS_IS_OK(status)) { error = smbd_smb2_request_error(smb2req, status); if (!NT_STATUS_IS_OK(error)) { smbd_server_connection_terminate(smb2req->xconn, nt_errstr(error)); return; } return; } outbody = smbd_smb2_generate_outbody(smb2req, 0x04); if (outbody.data == NULL) { error = smbd_smb2_request_error(smb2req, NT_STATUS_NO_MEMORY); if (!NT_STATUS_IS_OK(error)) { smbd_server_connection_terminate(smb2req->xconn, nt_errstr(error)); return; } return; } SSVAL(outbody.data, 0x00, 0x04); /* struct size */ SSVAL(outbody.data, 0x02, 0); /* reserved */ error = smbd_smb2_request_done(smb2req, outbody, NULL); if (!NT_STATUS_IS_OK(error)) { smbd_server_connection_terminate(smb2req->xconn, nt_errstr(error)); return; } } static void smbd_smb2_lock_cleanup(struct tevent_req *req, enum tevent_req_state req_state); static void smbd_smb2_lock_try(struct tevent_req *req); static void smbd_smb2_lock_retry(struct tevent_req *subreq); static bool smbd_smb2_lock_cancel(struct tevent_req *req); static struct tevent_req *smbd_smb2_lock_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev, struct smbd_smb2_request *smb2req, struct files_struct *fsp, uint32_t in_lock_sequence, uint16_t in_lock_count, struct smbd_smb2_lock_element *in_locks) { struct tevent_req *req; struct smbd_smb2_lock_state *state; bool isunlock = false; uint16_t i; struct smbd_lock_element *locks; NTSTATUS status; bool check_lock_sequence = false; uint32_t lock_sequence_bucket = 0; req = tevent_req_create(mem_ctx, &state, struct smbd_smb2_lock_state); if (req == NULL) { return NULL; } state->ev = ev; state->fsp = fsp; state->smb2req = smb2req; smb2req->subreq = req; /* So we can find this when going async. */ tevent_req_set_cleanup_fn(req, smbd_smb2_lock_cleanup); state->smb1req = smbd_smb2_fake_smb_request(smb2req); if (tevent_req_nomem(state->smb1req, req)) { return tevent_req_post(req, ev); } DEBUG(10,("smbd_smb2_lock_send: %s - %s\n", fsp_str_dbg(fsp), fsp_fnum_dbg(fsp))); /* * Windows sets check_lock_sequence = true * only for resilient and persistent handles. * * [MS-SMB2] 3.3.5.14 Receiving an SMB2 LOCK Request * * ... if Open.IsResilient or Open.IsDurable or Open.IsPersistent is * TRUE or if Connection.Dialect belongs to the SMB 3.x dialect family * and Connection.ServerCapabilities includes * SMB2_GLOBAL_CAP_MULTI_CHANNEL bit, the server SHOULD<314> * perform lock sequence * verification ... * <314> Section 3.3.5.14: Windows 7 and Windows Server 2008 R2 perform * lock sequence verification only when Open.IsResilient is TRUE. * Windows 8 through Windows 10 v1909 and Windows Server 2012 through * Windows Server v1909 perform lock sequence verification only when * Open.IsResilient or Open.IsPersistent is TRUE. * * Note <314> also applies to all versions (at least) up to * Windows Server v2004. * * Hopefully this will be fixed in future Windows versions and they * will avoid Note <314>. * * We implement what the specification says by default, but * allow "smb2 disable lock sequence checking = yes" to * behave like Windows again. * * Note: that we already check the dialect before setting * SMB2_CAP_MULTI_CHANNEL in smb2_negprot.c */ if (smb2req->xconn->smb2.server.capabilities & SMB2_CAP_MULTI_CHANNEL) { check_lock_sequence = true; } if (fsp->op->global->durable) { check_lock_sequence = true; } if (check_lock_sequence) { bool disable_lock_sequence_checking = lp_smb2_disable_lock_sequence_checking(); if (disable_lock_sequence_checking) { check_lock_sequence = false; } } if (check_lock_sequence) { state->lock_sequence_value = in_lock_sequence & 0xF; lock_sequence_bucket = in_lock_sequence >> 4; } if ((lock_sequence_bucket > 0) && (lock_sequence_bucket <= sizeof(fsp->op->global->lock_sequence_array))) { uint32_t idx = lock_sequence_bucket - 1; uint8_t *array = fsp->op->global->lock_sequence_array; state->lock_sequence_element = &array[idx]; } if (state->lock_sequence_element != NULL) { /* * The incoming 'state->lock_sequence_value' is masked with 0xF. * * Note per default '*state->lock_sequence_element' * is invalid, a value of 0xFF that can never match on * incoming value. */ if (*state->lock_sequence_element == state->lock_sequence_value) { DBG_INFO("replayed smb2 lock request detected: " "file %s, value %u, bucket %u\n", fsp_str_dbg(fsp), (unsigned)state->lock_sequence_value, (unsigned)lock_sequence_bucket); tevent_req_done(req); return tevent_req_post(req, ev); } /* * If it's not a replay, mark the element as * invalid again. */ *state->lock_sequence_element = 0xFF; } locks = talloc_array(state, struct smbd_lock_element, in_lock_count); if (locks == NULL) { tevent_req_nterror(req, NT_STATUS_NO_MEMORY); return tevent_req_post(req, ev); } switch (in_locks[0].flags) { case SMB2_LOCK_FLAG_SHARED: case SMB2_LOCK_FLAG_EXCLUSIVE: if (in_lock_count > 1) { tevent_req_nterror(req, NT_STATUS_INVALID_PARAMETER); return tevent_req_post(req, ev); } state->blocking = true; break; case SMB2_LOCK_FLAG_SHARED|SMB2_LOCK_FLAG_FAIL_IMMEDIATELY: case SMB2_LOCK_FLAG_EXCLUSIVE|SMB2_LOCK_FLAG_FAIL_IMMEDIATELY: break; case SMB2_LOCK_FLAG_UNLOCK: /* only the first lock gives the UNLOCK bit - see MS-SMB2 3.3.5.14 */ isunlock = true; break; default: tevent_req_nterror(req, NT_STATUS_INVALID_PARAMETER); return tevent_req_post(req, ev); } if (!isunlock && (in_lock_count > 1)) { /* * 3.3.5.14.2 says we SHOULD fail with INVALID_PARAMETER if we * have more than one lock and one of those is blocking. */ for (i=0; ismb1req, i); locks[i].smblctx = fsp->op->global->open_persistent_id; locks[i].offset = in_locks[i].offset; locks[i].count = in_locks[i].length; if (in_locks[i].flags & SMB2_LOCK_FLAG_EXCLUSIVE) { locks[i].brltype = WRITE_LOCK; } else if (in_locks[i].flags & SMB2_LOCK_FLAG_SHARED) { locks[i].brltype = READ_LOCK; } else if (invalid) { /* * this is an invalid UNLOCK element * and the backend needs to test for * brltype != UNLOCK_LOCK and return * NT_STATUS_INVALID_PARAMETER */ locks[i].brltype = READ_LOCK; } else { locks[i].brltype = UNLOCK_LOCK; } DBG_DEBUG("index %"PRIu16" offset=%"PRIu64", count=%"PRIu64", " "smblctx = %"PRIu64" type %d\n", i, locks[i].offset, locks[i].count, locks[i].smblctx, (int)locks[i].brltype); } state->locks = locks; state->lock_count = in_lock_count; if (isunlock) { status = smbd_do_unlocking( state->smb1req, fsp, in_lock_count, locks, WINDOWS_LOCK); if (tevent_req_nterror(req, status)) { return tevent_req_post(req, ev); } tevent_req_done(req); return tevent_req_post(req, ev); } smbd_smb2_lock_try(req); if (!tevent_req_is_in_progress(req)) { return tevent_req_post(req, ev); } tevent_req_defer_callback(req, smb2req->sconn->ev_ctx); aio_add_req_to_fsp(state->fsp, req); tevent_req_set_cancel_fn(req, smbd_smb2_lock_cancel); return req; } static void smbd_smb2_lock_cleanup(struct tevent_req *req, enum tevent_req_state req_state) { struct smbd_smb2_lock_state *state = tevent_req_data( req, struct smbd_smb2_lock_state); if (req_state != TEVENT_REQ_DONE) { return; } if (state->lock_sequence_element != NULL) { /* * On success we remember the given/incoming * value (which was masked with 0xF. */ *state->lock_sequence_element = state->lock_sequence_value; } } static void smbd_smb2_lock_update_retry_msecs( struct smbd_smb2_lock_state *state) { /* * The default lp_lock_spin_time() is 200ms, * we just use half of it to trigger the first retry. * * v_min is in the range of 0.001 to 10 secs * (0.1 secs by default) * * v_max is in the range of 0.01 to 100 secs * (1.0 secs by default) * * The typical steps are: * 0.1, 0.2, 0.3, 0.4, ... 1.0 */ uint32_t v_min = MAX(2, MIN(20000, lp_lock_spin_time()))/2; uint32_t v_max = 10 * v_min; if (state->retry_msecs >= v_max) { state->retry_msecs = v_max; return; } state->retry_msecs += v_min; } static void smbd_smb2_lock_update_polling_msecs( struct smbd_smb2_lock_state *state) { /* * The default lp_lock_spin_time() is 200ms. * * v_min is in the range of 0.002 to 20 secs * (0.2 secs by default) * * v_max is in the range of 0.02 to 200 secs * (2.0 secs by default) * * The typical steps are: * 0.2, 0.4, 0.6, 0.8, ... 2.0 */ uint32_t v_min = MAX(2, MIN(20000, lp_lock_spin_time())); uint32_t v_max = 10 * v_min; if (state->polling_msecs >= v_max) { state->polling_msecs = v_max; return; } state->polling_msecs += v_min; } static void smbd_smb2_lock_try(struct tevent_req *req) { struct smbd_smb2_lock_state *state = tevent_req_data( req, struct smbd_smb2_lock_state); struct share_mode_lock *lck = NULL; uint16_t blocker_idx; struct server_id blocking_pid = { 0 }; uint64_t blocking_smblctx; NTSTATUS status; struct tevent_req *subreq = NULL; struct timeval endtime = { 0 }; lck = get_existing_share_mode_lock( talloc_tos(), state->fsp->file_id); if (tevent_req_nomem(lck, req)) { return; } status = smbd_do_locks_try( state->fsp, WINDOWS_LOCK, state->lock_count, state->locks, &blocker_idx, &blocking_pid, &blocking_smblctx); if (NT_STATUS_IS_OK(status)) { TALLOC_FREE(lck); tevent_req_done(req); return; } if (NT_STATUS_EQUAL(status, NT_STATUS_RETRY)) { /* * We got NT_STATUS_RETRY, * we reset polling_msecs so that * that the retries based on LOCK_NOT_GRANTED * will later start with small intervalls again. */ state->polling_msecs = 0; /* * The backend wasn't able to decide yet. * We need to wait even for non-blocking * locks. * * The backend uses blocking_smblctx == UINT64_MAX * to indicate that we should use retry timers. * * It uses blocking_smblctx == 0 to indicate * it will use share_mode_wakeup_waiters() * to wake us. Note that unrelated changes in * locking.tdb may cause retries. */ if (blocking_smblctx != UINT64_MAX) { SMB_ASSERT(blocking_smblctx == 0); goto setup_retry; } smbd_smb2_lock_update_retry_msecs(state); DBG_DEBUG("Waiting for a backend decision. " "Retry in %"PRIu32" msecs\n", state->retry_msecs); /* * We completely ignore state->endtime here * we we'll wait for a backend decision forever. * If the backend is smart enough to implement * some NT_STATUS_RETRY logic, it has to * switch to any other status after in order * to avoid waiting forever. */ endtime = timeval_current_ofs_msec(state->retry_msecs); goto setup_retry; } if (NT_STATUS_EQUAL(status, NT_STATUS_FILE_LOCK_CONFLICT)) { /* * This is a bug and will be changed into an assert * in future version. We should only * ever get NT_STATUS_LOCK_NOT_GRANTED here! */ static uint64_t _bug_count; int _level = (_bug_count++ == 0) ? DBGLVL_ERR: DBGLVL_DEBUG; DBG_PREFIX(_level, ("BUG: Got %s mapping to " "NT_STATUS_LOCK_NOT_GRANTED\n", nt_errstr(status))); status = NT_STATUS_LOCK_NOT_GRANTED; } if (!NT_STATUS_EQUAL(status, NT_STATUS_LOCK_NOT_GRANTED)) { TALLOC_FREE(lck); tevent_req_nterror(req, status); return; } /* * We got LOCK_NOT_GRANTED, make sure * a following STATUS_RETRY will start * with short intervalls again. */ state->retry_msecs = 0; if (!state->blocking) { TALLOC_FREE(lck); tevent_req_nterror(req, status); return; } if (blocking_smblctx == UINT64_MAX) { smbd_smb2_lock_update_polling_msecs(state); DBG_DEBUG("Blocked on a posix lock. Retry in %"PRIu32" msecs\n", state->polling_msecs); endtime = timeval_current_ofs_msec(state->polling_msecs); } setup_retry: DBG_DEBUG("Watching share mode lock\n"); subreq = share_mode_watch_send( state, state->ev, lck, blocking_pid); TALLOC_FREE(lck); if (tevent_req_nomem(subreq, req)) { return; } tevent_req_set_callback(subreq, smbd_smb2_lock_retry, req); if (!timeval_is_zero(&endtime)) { bool ok; ok = tevent_req_set_endtime(subreq, state->ev, endtime); if (!ok) { tevent_req_oom(req); return; } } } static void smbd_smb2_lock_retry(struct tevent_req *subreq) { struct tevent_req *req = tevent_req_callback_data( subreq, struct tevent_req); struct smbd_smb2_lock_state *state = tevent_req_data( req, struct smbd_smb2_lock_state); NTSTATUS status; bool ok; /* * Make sure we run as the user again */ ok = change_to_user_and_service_by_fsp(state->fsp); if (!ok) { tevent_req_nterror(req, NT_STATUS_ACCESS_DENIED); return; } status = share_mode_watch_recv(subreq, NULL, NULL); TALLOC_FREE(subreq); if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT)) { /* * This is just a trigger for a timed retry. */ status = NT_STATUS_OK; } if (tevent_req_nterror(req, status)) { return; } smbd_smb2_lock_try(req); } static NTSTATUS smbd_smb2_lock_recv(struct tevent_req *req) { return tevent_req_simple_recv_ntstatus(req); } /**************************************************************** Cancel an outstanding blocking lock request. *****************************************************************/ static bool smbd_smb2_lock_cancel(struct tevent_req *req) { struct smbd_smb2_request *smb2req = NULL; struct smbd_smb2_lock_state *state = tevent_req_data(req, struct smbd_smb2_lock_state); if (!state) { return false; } if (!state->smb2req) { return false; } smb2req = state->smb2req; /* * If the request is canceled because of close, logoff or tdis * the status is NT_STATUS_RANGE_NOT_LOCKED instead of * NT_STATUS_CANCELLED. */ if (state->fsp->fsp_flags.closing || !NT_STATUS_IS_OK(smb2req->session->status) || !NT_STATUS_IS_OK(smb2req->tcon->status)) { tevent_req_nterror(req, NT_STATUS_RANGE_NOT_LOCKED); return true; } tevent_req_nterror(req, NT_STATUS_CANCELLED); return true; }