/*++ Copyright (c) 1992 Microsoft Corporation Module Name: elfsec.c Author: Dan Hinsley (danhi) 28-Mar-1992 Environment: Calls NT native APIs. Revision History: 27-Oct-1993 danl Make Eventlog service a DLL and attach it to services.exe. Removed functions that create well-known SIDs. This information is now passed into the Elfmain as a Global data structure containing all well-known SIDs. 28-Mar-1992 danhi created - based on scsec.c in svcctrl by ritaw 03-Mar-1995 markbl Added guest & anonymous logon log access restriction feature. --*/ #include #include #define PRIVILEGE_BUF_SIZE 512 // // // Local function prototypes // // // NTSTATUS ElfpGetPrivilege( IN DWORD numPrivileges, IN PULONG pulPrivileges ); NTSTATUS ElfpReleasePrivilege( VOID ); // // // Structure that describes the mapping of generic access rights to // // object specific access rights for a LogFile object. // // // static GENERIC_MAPPING LogFileObjectMapping = { STANDARD_RIGHTS_READ | // Generic read ELF_LOGFILE_READ, STANDARD_RIGHTS_WRITE | // Generic write ELF_LOGFILE_WRITE, STANDARD_RIGHTS_EXECUTE | // Generic execute ELF_LOGFILE_START | ELF_LOGFILE_STOP | ELF_LOGFILE_CONFIGURE, ELF_LOGFILE_ALL_ACCESS // Generic all }; // // // Functions // // // NTSTATUS ElfpCreateLogFileObject( PLOGFILE LogFile, DWORD Type, ULONG GuestAccessRestriction ) /*++ Routine Description: This function creates the security descriptor which represents an active log file. Arguments: LogFile - pointer the the LOGFILE structure for this logfile Return Value: --*/ { NTSTATUS Status; DWORD NumberOfAcesToUse; #define ELF_LOGFILE_OBJECT_ACES 10 // Number of ACEs in this DACL RTL_ACE_DATA AceData[ELF_LOGFILE_OBJECT_ACES] = { {ACCESS_DENIED_ACE_TYPE, 0, 0, ELF_LOGFILE_ALL_ACCESS, &AnonymousLogonSid}, {ACCESS_DENIED_ACE_TYPE, 0, 0, ELF_LOGFILE_ALL_ACCESS, &(ElfGlobalData->AliasGuestsSid)}, {ACCESS_ALLOWED_ACE_TYPE, 0, 0, ELF_LOGFILE_ALL_ACCESS, &(ElfGlobalData->LocalSystemSid)}, {ACCESS_ALLOWED_ACE_TYPE, 0, 0, ELF_LOGFILE_READ | ELF_LOGFILE_CLEAR, &(ElfGlobalData->AliasAdminsSid)}, {ACCESS_ALLOWED_ACE_TYPE, 0, 0, ELF_LOGFILE_BACKUP, &(ElfGlobalData->AliasBackupOpsSid)}, {ACCESS_ALLOWED_ACE_TYPE, 0, 0, ELF_LOGFILE_READ | ELF_LOGFILE_CLEAR, &(ElfGlobalData->AliasSystemOpsSid)}, {ACCESS_ALLOWED_ACE_TYPE, 0, 0, ELF_LOGFILE_READ, &(ElfGlobalData->WorldSid)}, {ACCESS_ALLOWED_ACE_TYPE, 0, 0, ELF_LOGFILE_WRITE, &(ElfGlobalData->AliasAdminsSid)}, {ACCESS_ALLOWED_ACE_TYPE, 0, 0, ELF_LOGFILE_WRITE, &(ElfGlobalData->AliasSystemOpsSid)}, {ACCESS_ALLOWED_ACE_TYPE, 0, 0, ELF_LOGFILE_WRITE, &(ElfGlobalData->WorldSid)} }; PRTL_ACE_DATA pAceData = NULL; // NON_SECURE logfiles let anyone read/write to them, secure ones // only let admins/local system do this. so for secure files we just // don't use the last ACE // Adjust the ACL start based on the passed GuestAccessRestriction flag. // The first two aces deny all log access to guests and/or anonymous // logons. The flag, GuestAccessRestriction, indicates that these two // deny access aces should be applied. Note that the deny aces and the // GuestAccessRestriction flag are not applicable to the security log, // since users and anonymous logons, by default, do not have access. switch (Type) { case ELF_LOGFILE_SECURITY: pAceData = AceData + 2; // Deny ACEs *not* applicable NumberOfAcesToUse = 3; break; case ELF_LOGFILE_SYSTEM: if (GuestAccessRestriction == ELF_GUEST_ACCESS_RESTRICTED) { pAceData = AceData; // Deny ACEs *applicable* NumberOfAcesToUse = 8; } else { pAceData = AceData + 2; // Deny ACEs *not* applicable NumberOfAcesToUse = 6; } break; case ELF_LOGFILE_APPLICATION: if (GuestAccessRestriction == ELF_GUEST_ACCESS_RESTRICTED) { pAceData = AceData; // Deny ACEs *applicable* NumberOfAcesToUse = 10; } else { pAceData = AceData + 2; // Deny ACEs *not* applicable NumberOfAcesToUse = 8; } break; } Status = RtlCreateUserSecurityObject( pAceData, NumberOfAcesToUse, NULL, // Owner NULL, // Group TRUE, // IsDirectoryObject &LogFileObjectMapping, &LogFile->Sd); if (!NT_SUCCESS(Status)) { ElfDbgPrintNC(( "[ELF] ElfpCreateLogFileObject: ElfCreateUserSecurityObject " "failed - %X\n", Status)); } return (Status); } VOID ElfpDeleteLogFileObject( PLOGFILE LogFile ) /*++ Routine Description: This function deletes the self-relative security descriptor which represents an eventlog logfile object. Arguments: LogFile - pointer the the LOGFILE structure for this logfile Return Value: None. --*/ { (void)RtlDeleteSecurityObject(&LogFile->Sd); } NTSTATUS ElfpAccessCheckAndAudit( IN LPWSTR SubsystemName, IN LPWSTR ObjectTypeName, IN LPWSTR ObjectName, IN OUT IELF_HANDLE ContextHandle, IN PSECURITY_DESCRIPTOR SecurityDescriptor, IN ACCESS_MASK DesiredAccess, IN PGENERIC_MAPPING GenericMapping, IN BOOL ForSecurityLog ) /*++ Routine Description: This function impersonates the caller so that it can perform access validation using NtAccessCheckAndAuditAlarm; and reverts back to itself before returning. Arguments: SubsystemName - Supplies a name string identifying the subsystem calling this routine. ObjectTypeName - Supplies the name of the type of the object being accessed. ObjectName - Supplies the name of the object being accessed. ContextHandle - Supplies the context handle to the object. On return, the granted access is written to the AccessGranted field of this structure if this call succeeds. SecurityDescriptor - A pointer to the Security Descriptor against which acccess is to be checked. DesiredAccess - Supplies desired acccess mask. This mask must have been previously mapped to contain no generic accesses. GenericMapping - Supplies a pointer to the generic mapping associated with this object type. ForSecurityLog - TRUE if the access check is for the security log. This is a special case that may require a privilege check. Return Value: NT status mapped to Win32 errors. --*/ { NTSTATUS Status; RPC_STATUS RpcStatus; UNICODE_STRING Subsystem; UNICODE_STRING ObjectType; UNICODE_STRING Object; BOOLEAN GenerateOnClose = FALSE; NTSTATUS AccessStatus; ACCESS_MASK GrantedAccess = 0; HANDLE ClientToken = NULL; PRIVILEGE_SET PrivilegeSet; ULONG PrivilegeSetLength = sizeof(PRIVILEGE_SET); ULONG privileges[1]; GenericMapping = &LogFileObjectMapping; RtlInitUnicodeString(&Subsystem, SubsystemName); RtlInitUnicodeString(&ObjectType, ObjectTypeName); RtlInitUnicodeString(&Object, ObjectName); if ((RpcStatus = RpcImpersonateClient(NULL)) != RPC_S_OK) { ElfDbgPrint(("[ELF] ElfpAccessCheckAndAudit: Failed to impersonate " "client %08lx\n", RpcStatus)); return RpcStatus; } // Get a token handle for the client Status = NtOpenThreadToken(NtCurrentThread(), TOKEN_QUERY, // DesiredAccess TRUE, // OpenAsSelf &ClientToken); if (!NT_SUCCESS(Status)) { ElfDbgPrint(("[ELF] ElfpAccessCheckAndAudit: NtOpenThreadToken Failed: " "0x%lx\n", Status)); goto CleanExit; } // We want to see if we can get the desired access, and if we do // then we also want all our other accesses granted. // MAXIMUM_ALLOWED gives us this. DesiredAccess |= MAXIMUM_ALLOWED; // Bug #57153 -- Make sure that the current user has the right to manage // the security log. Without this check, the Eventlog will allow all // administrators to manage the log, even if they don't have the access if (ForSecurityLog) { DesiredAccess |= ACCESS_SYSTEM_SECURITY; } Status = NtAccessCheck(SecurityDescriptor, ClientToken, DesiredAccess, GenericMapping, &PrivilegeSet, &PrivilegeSetLength, &GrantedAccess, &AccessStatus); if (!NT_SUCCESS(Status)) { ElfDbgPrint(("[ELF] ElfpAccessCheckAndAudit: Error calling " "NtAccessCheck %08lx\n", Status)); goto CleanExit; } if (AccessStatus != STATUS_SUCCESS) { ElfDbgPrint(("[ELF] ElfpAccessCheckAndAudit: Access status is %08lx\n", AccessStatus)); // MarkBl 1/30/95 : Modified this code a bit to give backup operators // the ability to open the security log for purposes // of backup. if ((AccessStatus == STATUS_ACCESS_DENIED) && (ForSecurityLog)) { // MarkBl 1/30/95 : First, evalutate the existing code (performed // for read or clear access), since its // privilege check is more rigorous than mine. Status = STATUS_ACCESS_DENIED; if (!(DesiredAccess & ELF_LOGFILE_WRITE)) { // If read or clear access to the security log is desired, // then we will see if this user passes the privilege check. // Do Privilege Check for SeSecurityPrivilege // (SE_SECURITY_NAME). // MarkBl 1/30/95 : Modified code to fall through on error // instead of the jump to 'CleanExit'. Status = ElfpTestClientPrivilege(SE_SECURITY_PRIVILEGE, ClientToken); if (NT_SUCCESS(Status)) { GrantedAccess |= (ELF_LOGFILE_READ | ELF_LOGFILE_CLEAR); } else { ElfDbgPrint(("[ELF] ElfpAccessCheckAndAudit: " "ElfpTestClientPrivilege failed %x\n", Status)); } } // MarkBl 1/30/95 : Finally, my code. If this user has backup // privilege, let the open succeed. if (!NT_SUCCESS(Status)) { Status = ElfpTestClientPrivilege(SE_BACKUP_PRIVILEGE, ClientToken); if (NT_SUCCESS(Status)) { GrantedAccess |= ELF_LOGFILE_BACKUP; } else { goto CleanExit; } } } else { Status = AccessStatus; } } // Revert to Self if ((RpcStatus = RpcRevertToSelf()) != RPC_S_OK) { ElfDbgPrint(("[ELF] ElfpAccessCheckAndAudit: Fail to revert to " "self %08lx\n", RpcStatus)); // We don't return the error status here because we don't want // to write over the other status that is being returned. } // Get SeAuditPrivilege so I can call NtOpenObjectAuditAlarm. // If any of this stuff fails, I don't want the status to overwrite the // status that I got back from the access and privilege checks. privileges[0] = SE_AUDIT_PRIVILEGE; AccessStatus = ElfpGetPrivilege(1, privileges); if (!NT_SUCCESS(AccessStatus)) { ElfDbgPrint(("[ELF] ElfpAccessCheckAndAudit: ElfpGetPrivilege " "(Enable) failed. Status is 0x%x\n", AccessStatus)); } // Call the Audit Alarm function. AccessStatus = NtOpenObjectAuditAlarm( &Subsystem, (PVOID)ContextHandle, &ObjectType, &Object, SecurityDescriptor, ClientToken, // Handle ClientToken DesiredAccess, GrantedAccess, &PrivilegeSet, // PPRIVLEGE_SET FALSE, // BOOLEAN ObjectCreation, TRUE, // BOOLEAN AccessGranted, &GenerateOnClose); if (!NT_SUCCESS(AccessStatus)) { ElfDbgPrint(("[ELF] ElfpAccessCheckAndAudit: NtOpenObjectAuditAlarm " "failed. status is 0x%lx\n", AccessStatus)); } else { if (GenerateOnClose) { ContextHandle->Flags |= ELF_LOG_HANDLE_GENERATE_ON_CLOSE; } } // Update the GrantedAccess in the context handle. ContextHandle->GrantedAccess = GrantedAccess; NtClose(ClientToken); ElfpReleasePrivilege(); return(Status); CleanExit: // Revert to Self if ((RpcStatus = RpcRevertToSelf()) != RPC_S_OK) { ElfDbgPrint(("[ELF] ElfpAccessCheckAndAudit: Fail to revert to " "self %08lx\n", RpcStatus)); // We don't return the error status here because we don't want // to write over the other status that is being returned. } if (ClientToken != NULL) { NtClose(ClientToken); } return(Status); } VOID ElfpCloseAudit( IN LPWSTR SubsystemName, IN IELF_HANDLE ContextHandle ) /*++ Routine Description: If the GenerateOnClose flag in the ContextHandle is set, then this function calls NtCloseAuditAlarm in order to generate a close audit for this handle. Arguments: ContextHandle - This is a pointer to an ELF_HANDLE structure. This is the handle that is being closed. Return Value: none. --*/ { UNICODE_STRING Subsystem; NTSTATUS Status; NTSTATUS AccessStatus; ULONG privileges[1]; RtlInitUnicodeString(&Subsystem, SubsystemName); if (ContextHandle->Flags & ELF_LOG_HANDLE_GENERATE_ON_CLOSE) { BOOLEAN WasEnabled = FALSE; // Get Audit Privilege privileges[0] = SE_AUDIT_PRIVILEGE; AccessStatus = ElfpGetPrivilege(1, privileges); if (!NT_SUCCESS(AccessStatus)) { ElfDbgPrint(("[ELF] ElfpCloseAudit: ElfpGetPrivilege " "(Enable) failed. Status is 0x%lx\n", AccessStatus)); } // Generate the Audit. Status = NtCloseObjectAuditAlarm( &Subsystem, ContextHandle, TRUE); if (!NT_SUCCESS(Status)) { ElfDbgPrint(("[ELF] ElfpCloseAudit: NtCloseObjectAuditAlarm Failed: " "0x%lx\n", Status)); } ContextHandle->Flags &= (~ELF_LOG_HANDLE_GENERATE_ON_CLOSE); ElfpReleasePrivilege(); #ifdef REMOVE // Release Audit Privilege Status = RtlAdjustPrivilege( SE_AUDIT_PRIVILEGE, FALSE, // Disable FALSE, // Use Process's token &WasEnabled); if (!NT_SUCCESS(Status)) { ElfDbgPrint(("[ELF] ElfpCloseAudit: RtlAdjustPrivilege " "(Disable) failed. Status is 0x%lx\n", Status)); } #endif } return; } NTSTATUS ElfpGetPrivilege( IN DWORD numPrivileges, IN PULONG pulPrivileges ) /*++ Routine Description: This function alters the privilege level for the current thread. It does this by duplicating the token for the current thread, and then applying the new privileges to that new token, then the current thread impersonates with that new token. Privileges can be relinquished by calling ElfpReleasePrivilege(). Arguments: numPrivileges - This is a count of the number of privileges in the array of privileges. pulPrivileges - This is a pointer to the array of privileges that are desired. This is an array of ULONGs. Return Value: NO_ERROR - If the operation was completely successful. Otherwise, it returns mapped return codes from the various NT functions that are called. --*/ { NTSTATUS ntStatus; HANDLE ourToken; HANDLE newToken; OBJECT_ATTRIBUTES Obja; SECURITY_QUALITY_OF_SERVICE SecurityQofS; ULONG returnLen; PTOKEN_PRIVILEGES pTokenPrivilege = NULL; DWORD i; // Initialize the Privileges Structure pTokenPrivilege = (PTOKEN_PRIVILEGES)LocalAlloc( LMEM_FIXED, sizeof(TOKEN_PRIVILEGES) + (sizeof(LUID_AND_ATTRIBUTES) * numPrivileges) ); if (pTokenPrivilege == NULL) { ElfDbgPrint(("[ELF] ElfpGetPrivilege:LocalAlloc Failed %d\n, GetLastError()")); return STATUS_NO_MEMORY; } pTokenPrivilege->PrivilegeCount = numPrivileges; for (i = 0; i < numPrivileges; i++) { pTokenPrivilege->Privileges[i].Luid = RtlConvertLongToLuid( pulPrivileges[i]); pTokenPrivilege->Privileges[i].Attributes = SE_PRIVILEGE_ENABLED; } // Initialize Object Attribute Structure. InitializeObjectAttributes(&Obja, NULL, 0L, NULL, NULL); // Initialize Security Quality Of Service Structure SecurityQofS.Length = sizeof(SECURITY_QUALITY_OF_SERVICE); SecurityQofS.ImpersonationLevel = SecurityImpersonation; SecurityQofS.ContextTrackingMode = FALSE; // Snapshot client context SecurityQofS.EffectiveOnly = FALSE; Obja.SecurityQualityOfService = &SecurityQofS; // Open our own Token ntStatus = NtOpenProcessToken(NtCurrentProcess(), TOKEN_DUPLICATE, &ourToken); if (!NT_SUCCESS(ntStatus)) { ElfDbgPrint(("[ELF] ElfpGetPrivilege: NtOpenThreadToken Failed " "0x%lx" "\n", ntStatus)); LocalFree(pTokenPrivilege); return ntStatus; } // Duplicate that Token ntStatus = NtDuplicateToken( ourToken, TOKEN_IMPERSONATE | TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &Obja, FALSE, // Duplicate the entire token TokenImpersonation, // TokenType &newToken); // Duplicate token if (!NT_SUCCESS(ntStatus)) { ElfDbgPrint(("[ELF] ElfpGetPrivilege: NtDuplicateToken Failed " "0x%lx" "\n", ntStatus)); LocalFree(pTokenPrivilege); NtClose(ourToken); return ntStatus; } // Add new privileges ntStatus = NtAdjustPrivilegesToken( newToken, // TokenHandle FALSE, // DisableAllPrivileges pTokenPrivilege, // NewState 0, // size of previous state buffer NULL, // no previous state info &returnLen); // numBytes required for buffer. if (!NT_SUCCESS(ntStatus)) { ElfDbgPrint(("[ELF] ElfpGetPrivilege: NtAdjustPrivilegesToken Failed " "0x%lx" "\n", ntStatus)); LocalFree(pTokenPrivilege); NtClose(ourToken); NtClose(newToken); return ntStatus; } // Begin impersonating with the new token ntStatus = NtSetInformationThread( NtCurrentThread(), ThreadImpersonationToken, (PVOID)&newToken, (ULONG)sizeof(HANDLE)); if (!NT_SUCCESS(ntStatus)) { ElfDbgPrint(("[ELF] ElfpGetPrivilege: NtAdjustPrivilegesToken Failed " "0x%lx" "\n", ntStatus)); LocalFree(pTokenPrivilege); NtClose(ourToken); NtClose(newToken); return ntStatus; } LocalFree(pTokenPrivilege); NtClose(ourToken); NtClose(newToken); return STATUS_SUCCESS; } NTSTATUS ElfpReleasePrivilege(VOID) /*++ Routine Description: This function relinquishes privileges obtained by calling ElfpGetPrivilege(). Arguments: none Return Value: NO_ERROR - If the operation was completely successful. Otherwise, it returns mapped return codes from the various NT functions that are called. --*/ { NTSTATUS ntStatus; HANDLE NewToken; // Revert To Self. NewToken = NULL; ntStatus = NtSetInformationThread(NtCurrentThread(), ThreadImpersonationToken, &NewToken, (ULONG)sizeof(HANDLE)); if (!NT_SUCCESS(ntStatus)) { return ntStatus; } return(NO_ERROR); } NTSTATUS ElfpTestClientPrivilege(IN ULONG ulPrivilege, IN HANDLE hThreadToken OPTIONAL) /*++ Routine Description: Checks if the client has the supplied privilege. Arguments: None Return Value: STATUS_SUCCESS - if the client has the appropriate privilege. STATUS_ACCESS_DENIED - client does not have the required privilege --*/ { NTSTATUS Status; PRIVILEGE_SET PrivilegeSet; BOOLEAN Privileged; HANDLE Token; RPC_STATUS RpcStatus; UNICODE_STRING SubSystemName; RtlInitUnicodeString(&SubSystemName, L"Eventlog"); if (hThreadToken != NULL) { Token = hThreadToken; } else { RpcStatus = RpcImpersonateClient(NULL); if (RpcStatus != RPC_S_OK) { ElfDbgPrint(("[ELF] ElfpTestClientPrivilege: " "RpcImpersonateClient FAILED 0x%lx\n", RpcStatus)); return RpcStatus; } Status = NtOpenThreadToken(NtCurrentThread(), TOKEN_QUERY, TRUE, &Token); if (!NT_SUCCESS(Status)) { // Forget it. ElfDbgPrint(("[ELF] ElfpTestClientPrivilege: " "NtOpenThreadToken FAILED 0x%lx\n", Status)); RpcRevertToSelf(); return Status; } } // See if the client has the required privilege PrivilegeSet.PrivilegeCount = 1; PrivilegeSet.Control = PRIVILEGE_SET_ALL_NECESSARY; PrivilegeSet.Privilege[0].Luid = RtlConvertLongToLuid(ulPrivilege); PrivilegeSet.Privilege[0].Attributes = SE_PRIVILEGE_ENABLED; Status = NtPrivilegeCheck(Token, &PrivilegeSet, &Privileged); if (NT_SUCCESS(Status) || (Status == STATUS_PRIVILEGE_NOT_HELD)) { Status = NtPrivilegeObjectAuditAlarm(&SubSystemName, NULL, Token, 0, &PrivilegeSet, Privileged); } if (hThreadToken == NULL) { // We impersonated inside of this function NtClose(Token); RpcRevertToSelf(); } // Handle unexpected errors if (!NT_SUCCESS(Status)) { return Status; } // If they failed the privilege check, return an error if (!Privileged) { return(STATUS_ACCESS_DENIED); } // They passed muster return STATUS_SUCCESS; }