From: Stefan Metzmacher Date: Wed, 30 Nov 2022 11:37:03 +0000 (+0100) Subject: CVE-2022-38023 s4:rpc_server/netlogon: improve CVE-2020-1472(ZeroLogon) debug messages X-Git-Tag: samba-4.15.13~83 X-Git-Url: http://git.samba.org/?a=commitdiff_plain;h=e02e8ad46b02a4c16f575b6371eea8ea66dee067;p=samba.git CVE-2022-38023 s4:rpc_server/netlogon: improve CVE-2020-1472(ZeroLogon) debug messages In order to avoid generating useless debug messages during make test, we will use 'CVE_2020_1472:warn_about_unused_debug_level = 3' and 'CVE_2020_1472:error_debug_level = 2' in order to avoid schannel warnings. Review with: git show -w BUG: https://bugzilla.samba.org/show_bug.cgi?id=15240 Signed-off-by: Stefan Metzmacher Reviewed-by: Andrew Bartlett Reviewed-by: Ralph Boehme (cherry picked from commit 16ee03efc194d9c1c2c746f63236b977a419918d) --- diff --git a/source4/rpc_server/netlogon/dcerpc_netlogon.c b/source4/rpc_server/netlogon/dcerpc_netlogon.c index 637be93dacc..d4bbb1261c3 100644 --- a/source4/rpc_server/netlogon/dcerpc_netlogon.c +++ b/source4/rpc_server/netlogon/dcerpc_netlogon.c @@ -641,15 +641,34 @@ static NTSTATUS dcesrv_netr_creds_server_step_check(struct dcesrv_call_state *dc bool schannel_required = schannel_global_required; const char *explicit_opt = NULL; struct netlogon_creds_CredentialState *creds = NULL; + int CVE_2020_1472_warn_level = lpcfg_parm_int(lp_ctx, NULL, + "CVE_2020_1472", "warn_about_unused_debug_level", DBGLVL_ERR); + int CVE_2020_1472_error_level = lpcfg_parm_int(lp_ctx, NULL, + "CVE_2020_1472", "error_debug_level", DBGLVL_ERR); + unsigned int dbg_lvl = DBGLVL_DEBUG; enum dcerpc_AuthType auth_type = DCERPC_AUTH_TYPE_NONE; + enum dcerpc_AuthLevel auth_level = DCERPC_AUTH_LEVEL_NONE; uint16_t opnum = dce_call->pkt.u.request.opnum; const char *opname = ""; + const char *reason = ""; if (opnum < ndr_table_netlogon.num_calls) { opname = ndr_table_netlogon.calls[opnum].name; } - dcesrv_call_auth_info(dce_call, &auth_type, NULL); + dcesrv_call_auth_info(dce_call, &auth_type, &auth_level); + + if (auth_type == DCERPC_AUTH_TYPE_SCHANNEL) { + if (auth_level == DCERPC_AUTH_LEVEL_PRIVACY) { + reason = "WITH SEALED"; + } else if (auth_level == DCERPC_AUTH_LEVEL_INTEGRITY) { + reason = "WITH SIGNED"; + } else { + smb_panic("Schannel without SIGN/SEAL"); + } + } else { + reason = "WITHOUT"; + } nt_status = schannel_check_creds_state(mem_ctx, lp_ctx, @@ -676,62 +695,108 @@ static NTSTATUS dcesrv_netr_creds_server_step_check(struct dcesrv_call_state *dc } if (auth_type == DCERPC_AUTH_TYPE_SCHANNEL) { - if (!schannel_required) { - DBG_ERR("CVE-2020-1472(ZeroLogon): " - "%s request (opnum[%u]) WITH schannel from " - "client_account[%s] client_computer_name[%s]\n", - opname, opnum, - log_escape(frame, creds->account_name), - log_escape(frame, creds->computer_name)); + nt_status = NT_STATUS_OK; + + if (explicit_opt != NULL && !schannel_required) { + dbg_lvl = MIN(dbg_lvl, CVE_2020_1472_warn_level); + } else if (!schannel_required) { + dbg_lvl = MIN(dbg_lvl, DBGLVL_INFO); } + + DEBUG(dbg_lvl, ( + "CVE-2020-1472(ZeroLogon): " + "%s request (opnum[%u]) %s schannel from " + "client_account[%s] client_computer_name[%s] %s\n", + opname, opnum, reason, + log_escape(frame, creds->account_name), + log_escape(frame, creds->computer_name), + nt_errstr(nt_status))); + if (explicit_opt != NULL && !schannel_required) { - DBG_ERR("CVE-2020-1472(ZeroLogon): " - "Option 'server require schannel:%s = no' not needed!?\n", - log_escape(frame, creds->account_name)); + DEBUG(CVE_2020_1472_warn_level, ( + "CVE-2020-1472(ZeroLogon): " + "Option 'server require schannel:%s = no' not needed for '%s'!\n", + log_escape(frame, creds->account_name), + log_escape(frame, creds->computer_name))); } *creds_out = creds; TALLOC_FREE(frame); - return NT_STATUS_OK; + return nt_status; } if (schannel_required) { - DBG_ERR("CVE-2020-1472(ZeroLogon): " - "%s request (opnum[%u]) without schannel from " - "client_account[%s] client_computer_name[%s]\n", - opname, opnum, - log_escape(frame, creds->account_name), - log_escape(frame, creds->computer_name)); - DBG_ERR("CVE-2020-1472(ZeroLogon): Check if option " - "'server require schannel:%s = no' " - "might be needed for a legacy client.\n", - log_escape(frame, creds->account_name)); + nt_status = NT_STATUS_ACCESS_DENIED; + + if (explicit_opt != NULL) { + dbg_lvl = MIN(dbg_lvl, DBGLVL_NOTICE); + } else { + dbg_lvl = MIN(dbg_lvl, CVE_2020_1472_error_level); + } + + DEBUG(dbg_lvl, ( + "CVE-2020-1472(ZeroLogon)/CVE-2022-38023: " + "%s request (opnum[%u]) %s schannel from " + "client_account[%s] client_computer_name[%s] %s\n", + opname, opnum, reason, + log_escape(frame, creds->account_name), + log_escape(frame, creds->computer_name), + nt_errstr(nt_status))); + if (explicit_opt != NULL) { + D_NOTICE("CVE-2020-1472(ZeroLogon): Option " + "'server require schannel:%s = yes' " + "rejects access for client.\n", + log_escape(frame, creds->account_name)); + } else { + DEBUG(CVE_2020_1472_error_level, ( + "CVE-2020-1472(ZeroLogon): Check if option " + "'server require schannel:%s = no' " + "might be needed for a legacy client.\n", + log_escape(frame, creds->account_name))); + } TALLOC_FREE(creds); ZERO_STRUCTP(return_authenticator); TALLOC_FREE(frame); - return NT_STATUS_ACCESS_DENIED; + return nt_status; } + nt_status = NT_STATUS_OK; + if (explicit_opt != NULL) { - DBG_INFO("CVE-2020-1472(ZeroLogon): " - "%s request (opnum[%u]) without schannel from " - "client_account[%s] client_computer_name[%s]\n", - opname, opnum, - log_escape(frame, creds->account_name), - log_escape(frame, creds->computer_name)); - DBG_INFO("CVE-2020-1472(ZeroLogon): " - "Option 'server require schannel:%s = no' still needed!\n", - log_escape(frame, creds->account_name)); + dbg_lvl = MIN(dbg_lvl, DBGLVL_INFO); } else { - DBG_ERR("CVE-2020-1472(ZeroLogon): " - "%s request (opnum[%u]) without schannel from " - "client_account[%s] client_computer_name[%s]\n", - opname, opnum, - log_escape(frame, creds->account_name), - log_escape(frame, creds->computer_name)); - DBG_ERR("CVE-2020-1472(ZeroLogon): Check if option " - "'server require schannel:%s = no' might be needed!\n", - log_escape(frame, creds->account_name)); + dbg_lvl = MIN(dbg_lvl, CVE_2020_1472_error_level); + } + + DEBUG(dbg_lvl, ( + "CVE-2020-1472(ZeroLogon)/CVE-2022-38023: " + "%s request (opnum[%u]) %s schannel from " + "client_account[%s] client_computer_name[%s] %s\n", + opname, opnum, reason, + log_escape(frame, creds->account_name), + log_escape(frame, creds->computer_name), + nt_errstr(nt_status))); + + if (explicit_opt != NULL) { + D_INFO("CVE-2020-1472(ZeroLogon): Option " + "'server require schannel:%s = no' " + "still needed for '%s'!\n", + log_escape(frame, creds->account_name), + log_escape(frame, creds->computer_name)); + } else { + /* + * admins should set + * server require schannel:COMPUTER$ = no + * in order to avoid the level 0 messages. + * Over time they can switch the global value + * to be strict. + */ + DEBUG(CVE_2020_1472_error_level, ( + "CVE-2020-1472(ZeroLogon): " + "Please use 'server require schannel:%s = no' " + "for '%s' to avoid this warning!\n", + log_escape(frame, creds->account_name), + log_escape(frame, creds->computer_name))); } *creds_out = creds;