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/* Copyright (c) 2000, 2010, 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 as published by
the Free Software Foundation; version 2 of the License.
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, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
#include "mysys_priv.h"
#include "m_string.h"
#ifdef __WIN__
/* 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 my_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.
*/
typedef struct st_my_security_attr
{
PSID everyone_sid;
PACL dacl;
} My_security_attr;
/*
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(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;
}
bzero(owner_token, 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(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)));
FreeSid(attr->everyone_sid);
my_free(attr->dacl);
my_free(sa);
}
}
#endif /* __WIN__ */
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