1/** @file 2 Authenticode Portable Executable Signature Verification over OpenSSL. 3 4 Caution: This module requires additional review when modified. 5 This library will have external input - signature (e.g. PE/COFF Authenticode). 6 This external input must be validated carefully to avoid security issue like 7 buffer overflow, integer overflow. 8 9 AuthenticodeVerify() will get PE/COFF Authenticode and will do basic check for 10 data structure. 11 12Copyright (c) 2011 - 2015, Intel Corporation. All rights reserved.<BR> 13This program and the accompanying materials 14are licensed and made available under the terms and conditions of the BSD License 15which accompanies this distribution. The full text of the license may be found at 16http://opensource.org/licenses/bsd-license.php 17 18THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 19WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 20 21**/ 22 23#include "InternalCryptLib.h" 24 25#include <openssl/objects.h> 26#include <openssl/x509.h> 27#include <openssl/pkcs7.h> 28 29// 30// OID ASN.1 Value for SPC_INDIRECT_DATA_OBJID 31// 32UINT8 mSpcIndirectOidValue[] = { 33 0x2B, 0x06, 0x01, 0x04, 0x01, 0x82, 0x37, 0x02, 0x01, 0x04 34 }; 35 36/** 37 Verifies the validility of a PE/COFF Authenticode Signature as described in "Windows 38 Authenticode Portable Executable Signature Format". 39 40 If AuthData is NULL, then return FALSE. 41 If ImageHash is NULL, then return FALSE. 42 43 Caution: This function may receive untrusted input. 44 PE/COFF Authenticode is external input, so this function will do basic check for 45 Authenticode data structure. 46 47 @param[in] AuthData Pointer to the Authenticode Signature retrieved from signed 48 PE/COFF image to be verified. 49 @param[in] DataSize Size of the Authenticode Signature in bytes. 50 @param[in] TrustedCert Pointer to a trusted/root certificate encoded in DER, which 51 is used for certificate chain verification. 52 @param[in] CertSize Size of the trusted certificate in bytes. 53 @param[in] ImageHash Pointer to the original image file hash value. The procudure 54 for calculating the image hash value is described in Authenticode 55 specification. 56 @param[in] HashSize Size of Image hash value in bytes. 57 58 @retval TRUE The specified Authenticode Signature is valid. 59 @retval FALSE Invalid Authenticode Signature. 60 61**/ 62BOOLEAN 63EFIAPI 64AuthenticodeVerify ( 65 IN CONST UINT8 *AuthData, 66 IN UINTN DataSize, 67 IN CONST UINT8 *TrustedCert, 68 IN UINTN CertSize, 69 IN CONST UINT8 *ImageHash, 70 IN UINTN HashSize 71 ) 72{ 73 BOOLEAN Status; 74 PKCS7 *Pkcs7; 75 CONST UINT8 *Temp; 76 CONST UINT8 *OrigAuthData; 77 UINT8 *SpcIndirectDataContent; 78 UINT8 Asn1Byte; 79 UINTN ContentSize; 80 CONST UINT8 *SpcIndirectDataOid; 81 82 // 83 // Check input parameters. 84 // 85 if ((AuthData == NULL) || (TrustedCert == NULL) || (ImageHash == NULL)) { 86 return FALSE; 87 } 88 89 if ((DataSize > INT_MAX) || (CertSize > INT_MAX) || (HashSize > INT_MAX)) { 90 return FALSE; 91 } 92 93 Status = FALSE; 94 Pkcs7 = NULL; 95 OrigAuthData = AuthData; 96 97 // 98 // Retrieve & Parse PKCS#7 Data (DER encoding) from Authenticode Signature 99 // 100 Temp = AuthData; 101 Pkcs7 = d2i_PKCS7 (NULL, &Temp, (int)DataSize); 102 if (Pkcs7 == NULL) { 103 goto _Exit; 104 } 105 106 // 107 // Check if it's PKCS#7 Signed Data (for Authenticode Scenario) 108 // 109 if (!PKCS7_type_is_signed (Pkcs7)) { 110 goto _Exit; 111 } 112 113 // 114 // NOTE: OpenSSL PKCS7 Decoder didn't work for Authenticode-format signed data due to 115 // some authenticode-specific structure. Use opaque ASN.1 string to retrieve 116 // PKCS#7 ContentInfo here. 117 // 118 SpcIndirectDataOid = OBJ_get0_data(Pkcs7->d.sign->contents->type); 119 if (OBJ_length(Pkcs7->d.sign->contents->type) != sizeof(mSpcIndirectOidValue) || 120 CompareMem ( 121 SpcIndirectDataOid, 122 mSpcIndirectOidValue, 123 sizeof (mSpcIndirectOidValue) 124 ) != 0) { 125 // 126 // Un-matched SPC_INDIRECT_DATA_OBJID. 127 // 128 goto _Exit; 129 } 130 131 132 SpcIndirectDataContent = (UINT8 *)(Pkcs7->d.sign->contents->d.other->value.asn1_string->data); 133 134 // 135 // Retrieve the SEQUENCE data size from ASN.1-encoded SpcIndirectDataContent. 136 // 137 Asn1Byte = *(SpcIndirectDataContent + 1); 138 139 if ((Asn1Byte & 0x80) == 0) { 140 // 141 // Short Form of Length Encoding (Length < 128) 142 // 143 ContentSize = (UINTN) (Asn1Byte & 0x7F); 144 // 145 // Skip the SEQUENCE Tag; 146 // 147 SpcIndirectDataContent += 2; 148 149 } else if ((Asn1Byte & 0x81) == 0x81) { 150 // 151 // Long Form of Length Encoding (128 <= Length < 255, Single Octet) 152 // 153 ContentSize = (UINTN) (*(UINT8 *)(SpcIndirectDataContent + 2)); 154 // 155 // Skip the SEQUENCE Tag; 156 // 157 SpcIndirectDataContent += 3; 158 159 } else if ((Asn1Byte & 0x82) == 0x82) { 160 // 161 // Long Form of Length Encoding (Length > 255, Two Octet) 162 // 163 ContentSize = (UINTN) (*(UINT8 *)(SpcIndirectDataContent + 2)); 164 ContentSize = (ContentSize << 8) + (UINTN)(*(UINT8 *)(SpcIndirectDataContent + 3)); 165 // 166 // Skip the SEQUENCE Tag; 167 // 168 SpcIndirectDataContent += 4; 169 170 } else { 171 goto _Exit; 172 } 173 174 // 175 // Compare the original file hash value to the digest retrieve from SpcIndirectDataContent 176 // defined in Authenticode 177 // NOTE: Need to double-check HashLength here! 178 // 179 if (CompareMem (SpcIndirectDataContent + ContentSize - HashSize, ImageHash, HashSize) != 0) { 180 // 181 // Un-matched PE/COFF Hash Value 182 // 183 goto _Exit; 184 } 185 186 // 187 // Verifies the PKCS#7 Signed Data in PE/COFF Authenticode Signature 188 // 189 Status = (BOOLEAN) Pkcs7Verify (OrigAuthData, DataSize, TrustedCert, CertSize, SpcIndirectDataContent, ContentSize); 190 191_Exit: 192 // 193 // Release Resources 194 // 195 PKCS7_free (Pkcs7); 196 197 return Status; 198} 199