/* Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License, version 2.0, as published by the Free Software Foundation. This program is also distributed with certain software (including but not limited to OpenSSL) that is licensed under separate terms, as designated in a particular file or component or in included license documentation. The authors of MySQL hereby grant you an additional permission to link the program and your derivative works with the separately licensed software that they have included with MySQL. 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, version 2.0, for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ /** @file mysys/my_windac.cc */ #ifdef _WIN32 #include "m_string.h" #include "my_pointer_arithmetic.h" #include "my_sys.h" #include "mysql/service_mysql_alloc.h" #include "mysys_priv.h" /* Windows NT/2000 discretionary access control utility functions. */ /* Check if the operating system is built on NT technology. RETURN 0 Windows 95/98/Me 1 otherwise */ static bool is_nt() { return GetVersion() < 0x80000000; } /* Auxilary structure to store pointers to the data which we need to keep around while SECURITY_ATTRIBUTES is in use. */ struct My_security_attr { PSID everyone_sid; PACL dacl; }; /* Allocate and initialize SECURITY_ATTRIBUTES setting up access rights for the owner and group `Everybody'. SYNOPSIS my_security_attr_create() psa [OUT] pointer to store the pointer to SA in perror [OUT] pointer to store error message if there was an error owner_rights [IN] access rights for the owner everyone_rights [IN] access rights for group Everybody DESCRIPTION Set up the security attributes to provide clients with sufficient access rights to a kernel object. We need this function because if we simply grant all access to everybody (by installing a NULL DACL) a mailicious user can attempt a denial of service attack by taking ownership over the kernel object. Upon successful return `psa' contains a pointer to SECUIRITY_ATTRIBUTES that can be used to create kernel objects with proper access rights. RETURN 0 success, psa is 0 or points to a valid SA structure, perror is left intact !0 error, SA is set to 0, error message is stored in perror */ int my_security_attr_create(SECURITY_ATTRIBUTES **psa, const char **perror, DWORD owner_rights, DWORD everyone_rights) { /* Top-level SID authority */ SID_IDENTIFIER_AUTHORITY world_auth = SECURITY_WORLD_SID_AUTHORITY; PSID everyone_sid = 0; HANDLE htoken = 0; SECURITY_ATTRIBUTES *sa = 0; PACL dacl = 0; DWORD owner_token_length, dacl_length; SECURITY_DESCRIPTOR *sd; PTOKEN_USER owner_token; PSID owner_sid; My_security_attr *attr; if (!is_nt()) { *psa = 0; return 0; } /* Get SID of Everyone group. Easier to retrieve all SIDs each time this function is called than worry about thread safety. */ if (!AllocateAndInitializeSid(&world_auth, 1, SECURITY_WORLD_RID, 0, 0, 0, 0, 0, 0, 0, &everyone_sid)) { *perror = "Failed to retrieve the SID of Everyone group"; goto error; } /* Get SID of the owner. Using GetSecurityInfo this task can be done in just one call instead of five, but GetSecurityInfo declared in aclapi.h, so I hesitate to use it. SIC: OpenThreadToken works only if there is an active impersonation token, hence OpenProcessToken is used. */ if (!OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &htoken)) { *perror = "Failed to retrieve thread access token"; goto error; } GetTokenInformation(htoken, TokenUser, 0, 0, &owner_token_length); if (!my_multi_malloc( key_memory_win_SECURITY_ATTRIBUTES, MYF(MY_WME), &sa, ALIGN_SIZE(sizeof(SECURITY_ATTRIBUTES)) + sizeof(My_security_attr), &sd, sizeof(SECURITY_DESCRIPTOR), &owner_token, owner_token_length, 0)) { *perror = "Failed to allocate memory for SECURITY_ATTRIBUTES"; goto error; } memset(owner_token, 0, owner_token_length); if (!GetTokenInformation(htoken, TokenUser, owner_token, owner_token_length, &owner_token_length)) { *perror = "GetTokenInformation failed"; goto error; } owner_sid = owner_token->User.Sid; if (!IsValidSid(owner_sid)) { *perror = "IsValidSid failed"; goto error; } /* Calculate the amount of memory that must be allocated for the DACL */ dacl_length = sizeof(ACL) + (sizeof(ACCESS_ALLOWED_ACE) - sizeof(DWORD)) * 2 + GetLengthSid(everyone_sid) + GetLengthSid(owner_sid); /* Create an ACL */ if (!(dacl = (PACL)my_malloc(key_memory_win_PACL, dacl_length, MYF(MY_ZEROFILL | MY_WME)))) { *perror = "Failed to allocate memory for DACL"; goto error; } if (!InitializeAcl(dacl, dacl_length, ACL_REVISION)) { *perror = "Failed to initialize DACL"; goto error; } if (!AddAccessAllowedAce(dacl, ACL_REVISION, everyone_rights, everyone_sid)) { *perror = "Failed to set up DACL"; goto error; } if (!AddAccessAllowedAce(dacl, ACL_REVISION, owner_rights, owner_sid)) { *perror = "Failed to set up DACL"; goto error; } if (!InitializeSecurityDescriptor(sd, SECURITY_DESCRIPTOR_REVISION)) { *perror = "Could not initialize security descriptor"; goto error; } if (!SetSecurityDescriptorDacl(sd, true, dacl, false)) { *perror = "Failed to install DACL"; goto error; } sa->nLength = sizeof(*sa); sa->bInheritHandle = true; sa->lpSecurityDescriptor = sd; /* Save pointers to everyone_sid and dacl to be able to clean them up */ attr = (My_security_attr *)(((char *)sa) + ALIGN_SIZE(sizeof(*sa))); attr->everyone_sid = everyone_sid; attr->dacl = dacl; *psa = sa; CloseHandle(htoken); return 0; error: if (everyone_sid) FreeSid(everyone_sid); if (htoken) CloseHandle(htoken); my_free(sa); my_free(dacl); *psa = 0; return 1; } /* Cleanup security attributes freeing used memory. SYNOPSIS my_security_attr_free() sa security attributes */ void my_security_attr_free(SECURITY_ATTRIBUTES *sa) { if (sa) { My_security_attr *attr = (My_security_attr *)(((char *)sa) + ALIGN_SIZE(sizeof(*sa))); PACL dacl_from_descriptor = nullptr; BOOL dacl_present_in_descriptor = FALSE; BOOL dacl_defaulted = FALSE; // If the DACL in the descriptor is not the same as that in the // My_security_attr, it will have been created by a call to SetEntriesInAcl // and thus must be freed by a call to LocalFree. if (GetSecurityDescriptorDacl(sa->lpSecurityDescriptor, &dacl_present_in_descriptor, &dacl_from_descriptor, &dacl_defaulted) && dacl_present_in_descriptor && !dacl_defaulted && attr->dacl != dacl_from_descriptor) { LocalFree(dacl_from_descriptor); } FreeSid(attr->everyone_sid); my_free(attr->dacl); my_free(sa); } } #endif /* _WIN32 */