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/*
* winsecur.c: implementation of winsecur.h.
*/
#include <stdio.h>
#include <stdlib.h>
#include "putty.h"
#if !defined NO_SECURITY
#define WINSECUR_GLOBAL
#include "winsecur.h"
int got_advapi(void)
{
static int attempted = FALSE;
static int successful;
static HMODULE advapi;
if (!attempted) {
attempted = TRUE;
advapi = load_system32_dll("advapi32.dll");
successful = advapi &&
GET_WINDOWS_FUNCTION(advapi, GetSecurityInfo) &&
GET_WINDOWS_FUNCTION(advapi, OpenProcessToken) &&
GET_WINDOWS_FUNCTION(advapi, GetTokenInformation) &&
GET_WINDOWS_FUNCTION(advapi, InitializeSecurityDescriptor) &&
GET_WINDOWS_FUNCTION(advapi, SetSecurityDescriptorOwner) &&
GET_WINDOWS_FUNCTION(advapi, SetEntriesInAclA);
}
return successful;
}
int got_crypt(void)
{
static int attempted = FALSE;
static int successful;
static HMODULE crypt;
if (!attempted) {
attempted = TRUE;
crypt = load_system32_dll("crypt32.dll");
successful = crypt &&
GET_WINDOWS_FUNCTION(crypt, CryptProtectMemory);
}
return successful;
}
PSID get_user_sid(void)
{
HANDLE proc = NULL, tok = NULL;
TOKEN_USER *user = NULL;
DWORD toklen, sidlen;
PSID sid = NULL, ret = NULL;
if (!got_advapi())
goto cleanup;
if ((proc = OpenProcess(MAXIMUM_ALLOWED, FALSE,
GetCurrentProcessId())) == NULL)
goto cleanup;
if (!p_OpenProcessToken(proc, TOKEN_QUERY, &tok))
goto cleanup;
if (!p_GetTokenInformation(tok, TokenUser, NULL, 0, &toklen) &&
GetLastError() != ERROR_INSUFFICIENT_BUFFER)
goto cleanup;
if ((user = (TOKEN_USER *)LocalAlloc(LPTR, toklen)) == NULL)
goto cleanup;
if (!p_GetTokenInformation(tok, TokenUser, user, toklen, &toklen))
goto cleanup;
sidlen = GetLengthSid(user->User.Sid);
sid = (PSID)smalloc(sidlen);
if (!CopySid(sidlen, sid, user->User.Sid))
goto cleanup;
/* Success. Move sid into the return value slot, and null it out
* to stop the cleanup code freeing it. */
ret = sid;
sid = NULL;
cleanup:
if (proc != NULL)
CloseHandle(proc);
if (tok != NULL)
CloseHandle(tok);
if (user != NULL)
LocalFree(user);
if (sid != NULL)
sfree(sid);
return ret;
}
int make_private_security_descriptor(DWORD permissions,
PSECURITY_DESCRIPTOR *psd,
PACL *acl,
char **error)
{
SID_IDENTIFIER_AUTHORITY world_auth = SECURITY_WORLD_SID_AUTHORITY;
SID_IDENTIFIER_AUTHORITY nt_auth = SECURITY_NT_AUTHORITY;
EXPLICIT_ACCESS ea[3];
int acl_err;
int ret = FALSE;
/* Initialised once, then kept around to reuse forever */
static PSID worldsid, networksid, usersid;
*psd = NULL;
*acl = NULL;
*error = NULL;
if (!got_advapi()) {
*error = dupprintf("unable to load advapi32.dll");
goto cleanup;
}
if (!usersid) {
if ((usersid = get_user_sid()) == NULL) {
*error = dupprintf("unable to construct SID for current user: %s",
win_strerror(GetLastError()));
goto cleanup;
}
}
if (!worldsid) {
if (!AllocateAndInitializeSid(&world_auth, 1, SECURITY_WORLD_RID,
0, 0, 0, 0, 0, 0, 0, &worldsid)) {
*error = dupprintf("unable to construct SID for world: %s",
win_strerror(GetLastError()));
goto cleanup;
}
}
if (!networksid) {
if (!AllocateAndInitializeSid(&nt_auth, 1, SECURITY_NETWORK_RID,
0, 0, 0, 0, 0, 0, 0, &networksid)) {
*error = dupprintf("unable to construct SID for "
"local same-user access only: %s",
win_strerror(GetLastError()));
goto cleanup;
}
}
memset(ea, 0, sizeof(ea));
ea[0].grfAccessPermissions = permissions;
ea[0].grfAccessMode = REVOKE_ACCESS;
ea[0].grfInheritance = NO_INHERITANCE;
ea[0].Trustee.TrusteeForm = TRUSTEE_IS_SID;
ea[0].Trustee.ptstrName = (LPTSTR)worldsid;
ea[1].grfAccessPermissions = permissions;
ea[1].grfAccessMode = GRANT_ACCESS;
ea[1].grfInheritance = NO_INHERITANCE;
ea[1].Trustee.TrusteeForm = TRUSTEE_IS_SID;
ea[1].Trustee.ptstrName = (LPTSTR)usersid;
ea[2].grfAccessPermissions = permissions;
ea[2].grfAccessMode = REVOKE_ACCESS;
ea[2].grfInheritance = NO_INHERITANCE;
ea[2].Trustee.TrusteeForm = TRUSTEE_IS_SID;
ea[2].Trustee.ptstrName = (LPTSTR)networksid;
acl_err = p_SetEntriesInAclA(3, ea, NULL, acl);
if (acl_err != ERROR_SUCCESS || *acl == NULL) {
*error = dupprintf("unable to construct ACL: %s",
win_strerror(acl_err));
goto cleanup;
}
*psd = (PSECURITY_DESCRIPTOR)
LocalAlloc(LPTR, SECURITY_DESCRIPTOR_MIN_LENGTH);
if (!*psd) {
*error = dupprintf("unable to allocate security descriptor: %s",
win_strerror(GetLastError()));
goto cleanup;
}
if (!InitializeSecurityDescriptor(*psd, SECURITY_DESCRIPTOR_REVISION)) {
*error = dupprintf("unable to initialise security descriptor: %s",
win_strerror(GetLastError()));
goto cleanup;
}
if (!SetSecurityDescriptorOwner(*psd, usersid, FALSE)) {
*error = dupprintf("unable to set owner in security descriptor: %s",
win_strerror(GetLastError()));
goto cleanup;
}
if (!SetSecurityDescriptorDacl(*psd, TRUE, *acl, FALSE)) {
*error = dupprintf("unable to set DACL in security descriptor: %s",
win_strerror(GetLastError()));
goto cleanup;
}
ret = TRUE;
cleanup:
if (!ret) {
if (*psd) {
LocalFree(*psd);
*psd = NULL;
}
if (*acl) {
LocalFree(*acl);
*acl = NULL;
}
} else {
sfree(*error);
*error = NULL;
}
return ret;
}
#endif /* !defined NO_SECURITY */
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