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* Also add a retry in PKI's GetSignatureName() * This should help with getting a "The downloaded executable is missing a digital signature" message when launching an update. * Closes #1130
584 lines
21 KiB
C
584 lines
21 KiB
C
/*
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* Rufus: The Reliable USB Formatting Utility
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* PKI functions (code signing, etc.)
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* Copyright © 2015-2016 Pete Batard <pete@akeo.ie>
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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, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU 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, see <http://www.gnu.org/licenses/>.
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*/
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/* Memory leaks detection - define _CRTDBG_MAP_ALLOC as preprocessor macro */
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#ifdef _CRTDBG_MAP_ALLOC
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#include <stdlib.h>
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#include <crtdbg.h>
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#endif
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#include <windows.h>
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#include <stdio.h>
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#include <wincrypt.h>
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#include <wintrust.h>
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#include "rufus.h"
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#include "resource.h"
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#include "msapi_utf8.h"
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#include "localization.h"
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#define ENCODING (X509_ASN_ENCODING | PKCS_7_ASN_ENCODING)
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// MinGW doesn't seem to have this one
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#if !defined(szOID_NESTED_SIGNATURE)
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#define szOID_NESTED_SIGNATURE "1.3.6.1.4.1.311.2.4.1"
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#endif
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// Signatures names we accept. Must be the the exact name, including capitalization,
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// that CertGetNameStringA(CERT_NAME_ATTR_TYPE, szOID_COMMON_NAME) returns.
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const char* cert_name[3] = { "Akeo Consulting", "Akeo Systems", "Pete Batard" };
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// For added security, we also validate the country code of the certificate recipient.
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const char* cert_country = "IE";
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typedef struct {
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LPWSTR lpszProgramName;
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LPWSTR lpszPublisherLink;
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LPWSTR lpszMoreInfoLink;
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} SPROG_PUBLISHERINFO, *PSPROG_PUBLISHERINFO;
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/*
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* FormatMessage does not handle PKI errors
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*/
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const char* WinPKIErrorString(void)
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{
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static char error_string[64];
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DWORD error_code = GetLastError();
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if (((error_code >> 16) != 0x8009) && ((error_code >> 16) != 0x800B))
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return WindowsErrorString();
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switch (error_code) {
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case NTE_BAD_UID:
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return "Bad UID.";
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case CRYPT_E_MSG_ERROR:
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return "An error occurred while performing an operation on a cryptographic message.";
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case CRYPT_E_UNKNOWN_ALGO:
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return "Unknown cryptographic algorithm.";
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case CRYPT_E_INVALID_MSG_TYPE:
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return "Invalid cryptographic message type.";
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case CRYPT_E_HASH_VALUE:
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return "The hash value is not correct";
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case CRYPT_E_ISSUER_SERIALNUMBER:
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return "Invalid issuer and/or serial number.";
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case CRYPT_E_BAD_LEN:
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return "The length specified for the output data was insufficient.";
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case CRYPT_E_BAD_ENCODE:
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return "An error occurred during encode or decode operation.";
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case CRYPT_E_FILE_ERROR:
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return "An error occurred while reading or writing to a file.";
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case CRYPT_E_NOT_FOUND:
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return "Cannot find object or property.";
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case CRYPT_E_EXISTS:
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return "The object or property already exists.";
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case CRYPT_E_NO_PROVIDER:
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return "No provider was specified for the store or object.";
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case CRYPT_E_DELETED_PREV:
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return "The previous certificate or CRL context was deleted.";
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case CRYPT_E_NO_MATCH:
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return "Cannot find the requested object.";
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case CRYPT_E_UNEXPECTED_MSG_TYPE:
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case CRYPT_E_NO_KEY_PROPERTY:
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case CRYPT_E_NO_DECRYPT_CERT:
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return "Private key or certificate issue";
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case CRYPT_E_BAD_MSG:
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return "Not a cryptographic message.";
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case CRYPT_E_NO_SIGNER:
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return "The signed cryptographic message does not have a signer for the specified signer index.";
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case CRYPT_E_REVOKED:
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return "The certificate is revoked.";
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case CRYPT_E_NO_REVOCATION_DLL:
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case CRYPT_E_NO_REVOCATION_CHECK:
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case CRYPT_E_REVOCATION_OFFLINE:
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case CRYPT_E_NOT_IN_REVOCATION_DATABASE:
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return "Cannot check certificate revocation.";
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case CRYPT_E_INVALID_NUMERIC_STRING:
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case CRYPT_E_INVALID_PRINTABLE_STRING:
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case CRYPT_E_INVALID_IA5_STRING:
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case CRYPT_E_INVALID_X500_STRING:
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case CRYPT_E_NOT_CHAR_STRING:
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return "Invalid string.";
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case CRYPT_E_SECURITY_SETTINGS:
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return "The cryptographic operation failed due to a local security option setting.";
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case CRYPT_E_NO_VERIFY_USAGE_CHECK:
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case CRYPT_E_VERIFY_USAGE_OFFLINE:
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return "Cannot complete usage check.";
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case CRYPT_E_NO_TRUSTED_SIGNER:
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return "None of the signers of the cryptographic message or certificate trust list is trusted.";
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case CERT_E_UNTRUSTEDROOT:
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return "The root certificate is not trusted.";
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case TRUST_E_NOSIGNATURE:
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return "Not digitally signed.";
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case TRUST_E_EXPLICIT_DISTRUST:
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return "One of the certificates used was marked as untrusted by the user.";
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case TRUST_E_TIME_STAMP:
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return "The timestamp could not be verified.";
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default:
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static_sprintf(error_string, "Unknown PKI error 0x%08lX", error_code);
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return error_string;
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}
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}
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// Mostly from https://support.microsoft.com/en-us/kb/323809
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char* GetSignatureName(const char* path, const char* country_code)
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{
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static char szSubjectName[128];
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char szCountry[3] = "__";
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char *p = NULL, *mpath = NULL;
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int i;
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BOOL r;
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HMODULE hm;
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HCERTSTORE hStore = NULL;
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HCRYPTMSG hMsg = NULL;
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PCCERT_CONTEXT pCertContext = NULL;
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DWORD dwSize, dwEncoding, dwContentType, dwFormatType;
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PCMSG_SIGNER_INFO pSignerInfo = NULL;
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DWORD dwSignerInfo = 0;
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CERT_INFO CertInfo = { 0 };
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SPROG_PUBLISHERINFO ProgPubInfo = { 0 };
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wchar_t *szFileName;
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// If the path is NULL, get the signature of the current runtime
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if (path == NULL) {
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szFileName = calloc(MAX_PATH, sizeof(wchar_t));
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if (szFileName == NULL)
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return NULL;
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hm = GetModuleHandle(NULL);
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if (hm == NULL) {
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uprintf("PKI: Could not get current executable handle: %s", WinPKIErrorString());
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goto out;
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}
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dwSize = GetModuleFileNameW(hm, szFileName, MAX_PATH);
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if ((dwSize == 0) || ((dwSize == MAX_PATH) && (GetLastError() == ERROR_INSUFFICIENT_BUFFER))) {
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uprintf("PKI: Could not get module filename: %s", WinPKIErrorString());
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goto out;
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}
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mpath = wchar_to_utf8(szFileName);
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} else {
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szFileName = utf8_to_wchar(path);
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}
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// Get message handle and store handle from the signed file.
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for (i = 0; i < 5; i++) {
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r = CryptQueryObject(CERT_QUERY_OBJECT_FILE, szFileName,
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CERT_QUERY_CONTENT_FLAG_PKCS7_SIGNED_EMBED, CERT_QUERY_FORMAT_FLAG_BINARY,
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0, &dwEncoding, &dwContentType, &dwFormatType, &hStore, &hMsg, NULL);
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if (r)
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break;
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if (i == 0)
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uprintf("PKI: Failed to get signature for '%s': %s", (path==NULL)?mpath:path, WinPKIErrorString());
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if (path == NULL)
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break;
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uprintf("PKI: Retrying...");
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Sleep(2000);
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}
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if (!r)
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goto out;
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// Get signer information size.
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r = CryptMsgGetParam(hMsg, CMSG_SIGNER_INFO_PARAM, 0, NULL, &dwSignerInfo);
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if (!r) {
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uprintf("PKI: Failed to get signer size: %s", WinPKIErrorString());
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goto out;
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}
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// Allocate memory for signer information.
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pSignerInfo = (PCMSG_SIGNER_INFO)calloc(dwSignerInfo, 1);
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if (!pSignerInfo) {
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uprintf("PKI: Could not allocate memory for signer information");
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goto out;
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}
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// Get Signer Information.
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r = CryptMsgGetParam(hMsg, CMSG_SIGNER_INFO_PARAM, 0, (PVOID)pSignerInfo, &dwSignerInfo);
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if (!r) {
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uprintf("PKI: Failed to get signer information: %s", WinPKIErrorString());
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goto out;
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}
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// Search for the signer certificate in the temporary certificate store.
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CertInfo.Issuer = pSignerInfo->Issuer;
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CertInfo.SerialNumber = pSignerInfo->SerialNumber;
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pCertContext = CertFindCertificateInStore(hStore, ENCODING, 0, CERT_FIND_SUBJECT_CERT, (PVOID)&CertInfo, NULL);
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if (!pCertContext) {
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uprintf("PKI: Failed to locate signer certificate in temporary store: %s", WinPKIErrorString());
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goto out;
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}
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// If a country code is provided, validate that the certificate we have is for the same country
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if (country_code != NULL) {
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dwSize = CertGetNameStringA(pCertContext, CERT_NAME_ATTR_TYPE, 0, szOID_COUNTRY_NAME,
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szCountry, sizeof(szCountry));
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if (dwSize < 2) {
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uprintf("PKI: Failed to get Country Code");
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goto out;
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}
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if (strcmpi(country_code, szCountry) != 0) {
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uprintf("PKI: Unexpected Country Code (Found '%s', expected '%s')", szCountry, country_code);
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goto out;
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}
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}
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// Isolate the signing certificate subject name
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dwSize = CertGetNameStringA(pCertContext, CERT_NAME_ATTR_TYPE, 0, szOID_COMMON_NAME,
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szSubjectName, sizeof(szSubjectName));
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if (dwSize <= 1) {
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uprintf("PKI: Failed to get Subject Name");
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goto out;
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}
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if (szCountry[0] == '_')
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uprintf("Binary executable is signed by '%s'", szSubjectName);
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else
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uprintf("Binary executable is signed by '%s' (%s)", szSubjectName, szCountry);
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p = szSubjectName;
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out:
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safe_free(mpath);
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safe_free(szFileName);
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safe_free(ProgPubInfo.lpszProgramName);
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safe_free(ProgPubInfo.lpszPublisherLink);
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safe_free(ProgPubInfo.lpszMoreInfoLink);
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safe_free(pSignerInfo);
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if (pCertContext != NULL)
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CertFreeCertificateContext(pCertContext);
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if (hStore != NULL)
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CertCloseStore(hStore, 0);
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if (hMsg != NULL)
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CryptMsgClose(hMsg);
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return p;
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}
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// The timestamping authorities we use are RFC 3161 compliant
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static uint64_t GetRFC3161TimeStamp(PCMSG_SIGNER_INFO pSignerInfo)
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{
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BOOL r, found = FALSE;
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DWORD n, dwSize = 0;
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PCRYPT_CONTENT_INFO pCounterSignerInfo = NULL;
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uint64_t ts = 0ULL;
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uint8_t *timestamp_token;
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size_t timestamp_token_size;
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char* timestamp_str;
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size_t timestamp_str_size;
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// Loop through unauthenticated attributes for szOID_RFC3161_counterSign OID
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for (n = 0; n < pSignerInfo->UnauthAttrs.cAttr; n++) {
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if (lstrcmpA(pSignerInfo->UnauthAttrs.rgAttr[n].pszObjId, szOID_RFC3161_counterSign) == 0) {
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// Depending on how Microsoft implemented their timestamp checks, and the fact that we are dealing
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// with UnauthAttrs, there's a possibility that an attacker may add a "fake" RFC 3161 countersigner
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// to try to trick us into using their timestamp data. Detect that.
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if (found) {
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uprintf("PKI: Multiple RFC 3161 countersigners found. This could indicate something very nasty...");
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return 0ULL;
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}
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found = TRUE;
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// Read the countersigner message data
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r = CryptDecodeObjectEx(PKCS_7_ASN_ENCODING, PKCS_CONTENT_INFO,
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pSignerInfo->UnauthAttrs.rgAttr[n].rgValue[0].pbData,
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pSignerInfo->UnauthAttrs.rgAttr[n].rgValue[0].cbData,
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CRYPT_DECODE_ALLOC_FLAG, NULL, (PVOID)&pCounterSignerInfo, &dwSize);
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if (!r) {
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uprintf("PKI: Could not retrieve RFC 3161 countersigner data: %s", WinPKIErrorString());
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continue;
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}
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// Get the RFC 3161 timestamp message
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timestamp_token = get_data_from_asn1(pCounterSignerInfo->Content.pbData,
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pCounterSignerInfo->Content.cbData, szOID_TIMESTAMP_TOKEN,
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// 0x04 = "Octet String" ASN.1 tag
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0x04, ×tamp_token_size);
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if (timestamp_token) {
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timestamp_str = get_data_from_asn1(timestamp_token, timestamp_token_size, NULL,
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// 0x18 = "Generalized Time" ASN.1 tag
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0x18, ×tamp_str_size);
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if (timestamp_str) {
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// As per RFC 3161 The syntax is: YYYYMMDDhhmmss[.s...]Z
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if ((timestamp_str_size < 14) || (timestamp_str[timestamp_str_size - 1] != 'Z')) {
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// Sanity checks
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uprintf("PKI: Not an RFC 3161 timestamp");
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DumpBufferHex(timestamp_str, timestamp_str_size);
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} else {
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ts = strtoull(timestamp_str, NULL, 10);
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}
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}
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}
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LocalFree(pCounterSignerInfo);
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}
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}
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return ts;
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}
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// The following is used to get the RFP 3161 timestamp of a nested signature
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static uint64_t GetNestedRFC3161TimeStamp(PCMSG_SIGNER_INFO pSignerInfo)
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{
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BOOL r, found = FALSE;
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DWORD n, dwSize = 0;
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PCRYPT_CONTENT_INFO pNestedSignature = NULL;
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PCMSG_SIGNER_INFO pNestedSignerInfo = NULL;
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HCRYPTMSG hMsg = NULL;
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uint64_t ts = 0ULL;
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|
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// Loop through unauthenticated attributes for szOID_NESTED_SIGNATURE OID
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for (n = 0; ; n++) {
|
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if (pNestedSignature != NULL) {
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LocalFree(pNestedSignature);
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pNestedSignature = NULL;
|
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}
|
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if (hMsg != NULL) {
|
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CryptMsgClose(hMsg);
|
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hMsg = NULL;
|
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}
|
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safe_free(pNestedSignerInfo);
|
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if (n >= pSignerInfo->UnauthAttrs.cAttr)
|
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break;
|
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if (lstrcmpA(pSignerInfo->UnauthAttrs.rgAttr[n].pszObjId, szOID_NESTED_SIGNATURE) == 0) {
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if (found) {
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uprintf("PKI: Multiple nested signatures found. This could indicate something very nasty...");
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return 0ULL;
|
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}
|
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found = TRUE;
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r = CryptDecodeObjectEx(PKCS_7_ASN_ENCODING, PKCS_CONTENT_INFO,
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pSignerInfo->UnauthAttrs.rgAttr[n].rgValue[0].pbData,
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pSignerInfo->UnauthAttrs.rgAttr[n].rgValue[0].cbData,
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CRYPT_DECODE_ALLOC_FLAG, NULL, (PVOID)&pNestedSignature, &dwSize);
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if (!r) {
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uprintf("PKI: Could not retrieve nested signature data: %s", WinPKIErrorString());
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continue;
|
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}
|
|
|
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hMsg = CryptMsgOpenToDecode(ENCODING, CMSG_DETACHED_FLAG, CMSG_SIGNED, (HCRYPTPROV)NULL, NULL, NULL);
|
|
if (hMsg == NULL) {
|
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uprintf("PKI: Could not create nested signature message: %s", WinPKIErrorString());
|
|
continue;
|
|
}
|
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r = CryptMsgUpdate(hMsg, pNestedSignature->Content.pbData, pNestedSignature->Content.cbData, TRUE);
|
|
if (!r) {
|
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uprintf("PKI: Could not update message: %s", WinPKIErrorString());
|
|
continue;
|
|
}
|
|
// Get nested signer
|
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r = CryptMsgGetParam(hMsg, CMSG_SIGNER_INFO_PARAM, 0, NULL, &dwSize);
|
|
if (!r) {
|
|
uprintf("PKI: Failed to get nested signer size: %s", WinPKIErrorString());
|
|
continue;
|
|
}
|
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pNestedSignerInfo = (PCMSG_SIGNER_INFO)calloc(dwSize, 1);
|
|
if (!pNestedSignerInfo) {
|
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uprintf("PKI: Could not allocate memory for nested signer");
|
|
continue;
|
|
}
|
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r = CryptMsgGetParam(hMsg, CMSG_SIGNER_INFO_PARAM, 0, (PVOID)pNestedSignerInfo, &dwSize);
|
|
if (!r) {
|
|
uprintf("PKI: Failed to get nested signer information: %s", WinPKIErrorString());
|
|
continue;
|
|
}
|
|
ts = GetRFC3161TimeStamp(pNestedSignerInfo);
|
|
}
|
|
}
|
|
return ts;
|
|
}
|
|
|
|
// Return the signature timestamp (as a YYYYMMDDHHMMSS value) or 0 on error
|
|
uint64_t GetSignatureTimeStamp(const char* path)
|
|
{
|
|
char *mpath = NULL;
|
|
BOOL r;
|
|
HMODULE hm;
|
|
HCERTSTORE hStore = NULL;
|
|
HCRYPTMSG hMsg = NULL;
|
|
DWORD dwSize, dwEncoding, dwContentType, dwFormatType;
|
|
PCMSG_SIGNER_INFO pSignerInfo = NULL;
|
|
DWORD dwSignerInfo = 0;
|
|
wchar_t *szFileName;
|
|
uint64_t timestamp = 0ULL, nested_timestamp;
|
|
|
|
// If the path is NULL, get the signature of the current runtime
|
|
if (path == NULL) {
|
|
szFileName = calloc(MAX_PATH, sizeof(wchar_t));
|
|
if (szFileName == NULL)
|
|
goto out;
|
|
hm = GetModuleHandle(NULL);
|
|
if (hm == NULL) {
|
|
uprintf("PKI: Could not get current executable handle: %s", WinPKIErrorString());
|
|
goto out;
|
|
}
|
|
dwSize = GetModuleFileNameW(hm, szFileName, MAX_PATH);
|
|
if ((dwSize == 0) || ((dwSize == MAX_PATH) && (GetLastError() == ERROR_INSUFFICIENT_BUFFER))) {
|
|
uprintf("PKI: Could not get module filename: %s", WinPKIErrorString());
|
|
goto out;
|
|
}
|
|
mpath = wchar_to_utf8(szFileName);
|
|
} else {
|
|
szFileName = utf8_to_wchar(path);
|
|
}
|
|
|
|
// Get message handle and store handle from the signed file.
|
|
r = CryptQueryObject(CERT_QUERY_OBJECT_FILE, szFileName,
|
|
CERT_QUERY_CONTENT_FLAG_PKCS7_SIGNED_EMBED, CERT_QUERY_FORMAT_FLAG_BINARY,
|
|
0, &dwEncoding, &dwContentType, &dwFormatType, &hStore, &hMsg, NULL);
|
|
if (!r) {
|
|
uprintf("PKI: Failed to get signature for '%s': %s", (path==NULL)?mpath:path, WinPKIErrorString());
|
|
goto out;
|
|
}
|
|
|
|
// Get signer information size.
|
|
r = CryptMsgGetParam(hMsg, CMSG_SIGNER_INFO_PARAM, 0, NULL, &dwSignerInfo);
|
|
if (!r) {
|
|
uprintf("PKI: Failed to get signer size: %s", WinPKIErrorString());
|
|
goto out;
|
|
}
|
|
|
|
// Allocate memory for signer information.
|
|
pSignerInfo = (PCMSG_SIGNER_INFO)calloc(dwSignerInfo, 1);
|
|
if (!pSignerInfo) {
|
|
uprintf("PKI: Could not allocate memory for signer information");
|
|
goto out;
|
|
}
|
|
|
|
// Get Signer Information.
|
|
r = CryptMsgGetParam(hMsg, CMSG_SIGNER_INFO_PARAM, 0, (PVOID)pSignerInfo, &dwSignerInfo);
|
|
if (!r) {
|
|
uprintf("PKI: Failed to get signer information: %s", WinPKIErrorString());
|
|
goto out;
|
|
}
|
|
|
|
// Get the RFC 3161 timestamp
|
|
timestamp = GetRFC3161TimeStamp(pSignerInfo);
|
|
if (timestamp)
|
|
uprintf("Note: '%s' has timestamp %s", (path==NULL)?mpath:path, TimestampToHumanReadable(timestamp));
|
|
// Because we are currently using both SHA-1 and SHA-256 signatures, we are in the very specific
|
|
// situation that Windows may say our executable passes Authenticode validation on Windows 7 or
|
|
// later (which includes timestamp validation) even if the SHA-1 signature or timestamps have
|
|
// been altered.
|
|
// This means that, if we don't also check the nested SHA-256 signature timestamp, an attacker
|
|
// could alter the SHA-1 one (which is the one we use by default for chronology validation) and
|
|
// trick us into using an invalid timestamp value. To prevent this, we validate that, if we have
|
|
// both a regular and nested timestamp, they are within 60 seconds of each other.
|
|
nested_timestamp = GetNestedRFC3161TimeStamp(pSignerInfo);
|
|
if (nested_timestamp)
|
|
uprintf("Note: '%s' has nested timestamp %s", (path==NULL)?mpath:path, TimestampToHumanReadable(nested_timestamp));
|
|
if ((timestamp != 0ULL) && (nested_timestamp != 0ULL)) {
|
|
if (_abs64(nested_timestamp - timestamp) > 100) {
|
|
uprintf("PKI: Signature timestamp and nested timestamp differ by more than a minute. "
|
|
"This could indicate something very nasty...", timestamp, nested_timestamp);
|
|
timestamp = 0ULL;
|
|
}
|
|
}
|
|
|
|
out:
|
|
safe_free(mpath);
|
|
safe_free(szFileName);
|
|
safe_free(pSignerInfo);
|
|
if (hStore != NULL)
|
|
CertCloseStore(hStore, 0);
|
|
if (hMsg != NULL)
|
|
CryptMsgClose(hMsg);
|
|
return timestamp;
|
|
}
|
|
|
|
// From https://msdn.microsoft.com/en-us/library/windows/desktop/aa382384.aspx
|
|
LONG ValidateSignature(HWND hDlg, const char* path)
|
|
{
|
|
LONG r;
|
|
WINTRUST_DATA trust_data = { 0 };
|
|
WINTRUST_FILE_INFO trust_file = { 0 };
|
|
GUID guid_generic_verify = // WINTRUST_ACTION_GENERIC_VERIFY_V2
|
|
{ 0xaac56b, 0xcd44, 0x11d0,{ 0x8c, 0xc2, 0x0, 0xc0, 0x4f, 0xc2, 0x95, 0xee } };
|
|
char *signature_name;
|
|
size_t i;
|
|
uint64_t current_ts, update_ts;
|
|
|
|
// Check the signature name. Make it specific enough (i.e. don't simply check for "Akeo")
|
|
// so that, besides hacking our server, it'll place an extra hurdle on any malicious entity
|
|
// into also fooling a C.A. to issue a certificate that passes our test.
|
|
signature_name = GetSignatureName(path, cert_country);
|
|
if (signature_name == NULL) {
|
|
uprintf("PKI: Could not get signature name");
|
|
MessageBoxExU(hDlg, lmprintf(MSG_284), lmprintf(MSG_283), MB_OK | MB_ICONERROR | MB_IS_RTL, selected_langid);
|
|
return TRUST_E_NOSIGNATURE;
|
|
}
|
|
for (i = 0; i < ARRAYSIZE(cert_name); i++) {
|
|
if (strcmp(signature_name, cert_name[i]) == 0)
|
|
break;
|
|
}
|
|
if (i >= ARRAYSIZE(cert_name)) {
|
|
uprintf("PKI: Signature '%s' is unexpected...", signature_name);
|
|
if (MessageBoxExU(hDlg, lmprintf(MSG_285, signature_name), lmprintf(MSG_283),
|
|
MB_YESNO | MB_ICONWARNING | MB_IS_RTL, selected_langid) != IDYES)
|
|
return TRUST_E_EXPLICIT_DISTRUST;
|
|
}
|
|
|
|
trust_file.cbStruct = sizeof(trust_file);
|
|
trust_file.pcwszFilePath = utf8_to_wchar(path);
|
|
if (trust_file.pcwszFilePath == NULL) {
|
|
uprintf("PKI: Unable to convert '%s' to UTF16", path);
|
|
return ERROR_SEVERITY_ERROR | FAC(FACILITY_CERT) | ERROR_NOT_ENOUGH_MEMORY;
|
|
}
|
|
|
|
trust_data.cbStruct = sizeof(trust_data);
|
|
// NB: WTD_UI_ALL can result in ERROR_SUCCESS even if the signature validation fails,
|
|
// because it still prompts the user to run untrusted software, even after explicitly
|
|
// notifying them that the signature invalid (and of course Microsoft had to make
|
|
// that UI prompt a bit too similar to the other benign prompt you get when running
|
|
// trusted software, which, as per cert.org's assessment, may confuse non-security
|
|
// conscious-users who decide to gloss over these kind of notifications).
|
|
trust_data.dwUIChoice = WTD_UI_NONE;
|
|
// We just downloaded from the Internet, so we should be able to check revocation
|
|
trust_data.fdwRevocationChecks = WTD_REVOKE_WHOLECHAIN;
|
|
// 0x400 = WTD_MOTW for Windows 8.1 or later
|
|
trust_data.dwProvFlags = WTD_REVOCATION_CHECK_CHAIN | 0x400;
|
|
trust_data.dwUnionChoice = WTD_CHOICE_FILE;
|
|
trust_data.pFile = &trust_file;
|
|
|
|
r = WinVerifyTrustEx(INVALID_HANDLE_VALUE, &guid_generic_verify, &trust_data);
|
|
safe_free(trust_file.pcwszFilePath);
|
|
switch (r) {
|
|
case ERROR_SUCCESS:
|
|
// Verify that the timestamp of the downloaded update is in the future of our current one.
|
|
// This is done to prevent the use of an officially signed, but older binary, as potential attack vector.
|
|
current_ts = GetSignatureTimeStamp(NULL);
|
|
if (current_ts == 0ULL) {
|
|
uprintf("PKI: Cannot retreive the current binary's timestamp - Aborting update");
|
|
r = TRUST_E_TIME_STAMP;
|
|
} else {
|
|
update_ts = GetSignatureTimeStamp(path);
|
|
if (update_ts < current_ts) {
|
|
uprintf("PKI: Update timestamp (%" PRIi64 ") is younger than ours (%" PRIi64 ") - Aborting update", update_ts, current_ts);
|
|
r = TRUST_E_TIME_STAMP;
|
|
}
|
|
}
|
|
if (r != ERROR_SUCCESS)
|
|
MessageBoxExU(hDlg, lmprintf(MSG_300), lmprintf(MSG_299), MB_OK | MB_ICONERROR | MB_IS_RTL, selected_langid);
|
|
break;
|
|
case TRUST_E_NOSIGNATURE:
|
|
// Should already have been reported, but since we have a custom message for it...
|
|
uprintf("PKI: File does not appear to be signed: %s", WinPKIErrorString());
|
|
MessageBoxExU(hDlg, lmprintf(MSG_284), lmprintf(MSG_283), MB_OK | MB_ICONERROR | MB_IS_RTL, selected_langid);
|
|
break;
|
|
default:
|
|
uprintf("PKI: Failed to validate signature: %s", WinPKIErrorString());
|
|
MessageBoxExU(hDlg, lmprintf(MSG_240), lmprintf(MSG_283), MB_OK | MB_ICONERROR | MB_IS_RTL, selected_langid);
|
|
break;
|
|
}
|
|
|
|
return r;
|
|
}
|