89 lines
4.3 KiB
C
89 lines
4.3 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/calls.h"
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#include "libc/calls/internal.h"
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#include "libc/nt/enum/accessmask.h"
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#include "libc/nt/enum/securityinformation.h"
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#include "libc/nt/errors.h"
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#include "libc/nt/files.h"
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#include "libc/nt/runtime.h"
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#include "libc/nt/struct/genericmapping.h"
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#include "libc/nt/struct/privilegeset.h"
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#include "libc/nt/struct/securitydescriptor.h"
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#include "libc/runtime/runtime.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/ok.h"
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/**
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* Asks Microsoft if we're authorized to use a folder or file.
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*
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* Implementation Details: MSDN documentation imposes no limit on the
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* internal size of SECURITY_DESCRIPTOR, which we are responsible for
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* allocating. We've selected 1024 which shall hopefully be adequate.
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*
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* @param flags can have R_OK, W_OK, X_OK, etc.
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* @return 0 if authorized, or -1 w/ errno
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* @kudos Aaron Ballman for teaching this
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* @see libc/sysv/consts.sh
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*/
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textwindows int ntaccesscheck(const char16_t *pathname, uint32_t flags) {
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int rc;
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bool32 result;
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struct NtGenericMapping mapping;
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struct NtPrivilegeSet privileges;
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int64_t hToken, hImpersonatedToken;
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uint32_t secsize, granted, privsize;
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union NtSecurityDescriptorLol {
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struct NtSecurityDescriptor s;
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char b[1024];
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} security;
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granted = 0;
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result = false;
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secsize = sizeof(security);
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privsize = sizeof(privileges);
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memset(&privileges, 0, sizeof(privileges));
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mapping.GenericRead = kNtFileGenericRead;
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mapping.GenericWrite = kNtFileGenericWrite;
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mapping.GenericExecute = kNtFileGenericExecute;
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mapping.GenericAll = kNtFileAllAccess;
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MapGenericMask(&flags, &mapping);
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hImpersonatedToken = hToken = -1;
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if (GetFileSecurity(pathname,
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kNtOwnerSecurityInformation |
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kNtGroupSecurityInformation |
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kNtDaclSecurityInformation,
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&security.s, 0, &secsize) &&
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OpenProcessToken(GetCurrentProcess(),
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kNtTokenImpersonate | kNtTokenQuery | kNtTokenDuplicate |
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kNtStandardRightsRead,
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&hToken) &&
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DuplicateToken(hToken, kNtSecurityImpersonation, &hImpersonatedToken) &&
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AccessCheck(&security.s, hImpersonatedToken, flags, &mapping, &privileges,
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&privsize, &granted, &result) &&
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(result || flags == F_OK)) {
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rc = 0;
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} else {
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rc = winerr();
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}
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close(hImpersonatedToken);
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close(hToken);
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return rc;
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}
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