CryptoPkg/Library/BaseCryptLib/Pk/CryptAuthenticode.c

   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
  12 Copyright (c) 2011 - 2012, Intel Corporation. All rights reserved.<BR>
  13 This program and the accompanying materials
  14 are licensed and made available under the terms and conditions of the BSD License
  15 which accompanies this distribution.  The full text of the license may be found at
  16 http://opensource.org/licenses/bsd-license.php
  17
  18 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  19 WITHOUT 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 /**
  31   Verifies the validility of a PE/COFF Authenticode Signature as described in "Windows
  32   Authenticode Portable Executable Signature Format".
  33
  34   If AuthData is NULL, then return FALSE.
  35   If ImageHash is NULL, then return FALSE.
  36
  37   Caution: This function may receive untrusted input.
  38   PE/COFF Authenticode is external input, so this function will do basic check for
  39   Authenticode data structure.
  40
  41   @param[in]  AuthData     Pointer to the Authenticode Signature retrieved from signed
  42                            PE/COFF image to be verified.
  43   @param[in]  DataSize     Size of the Authenticode Signature in bytes.
  44   @param[in]  TrustedCert  Pointer to a trusted/root certificate encoded in DER, which
  45                            is used for certificate chain verification.
  46   @param[in]  CertSize     Size of the trusted certificate in bytes.
  47   @param[in]  ImageHash    Pointer to the original image file hash value. The procudure
  48                            for calculating the image hash value is described in Authenticode
  49                            specification.
  50   @param[in]  HashSize     Size of Image hash value in bytes.
  51
  52   @retval  TRUE   The specified Authenticode Signature is valid.
  53   @retval  FALSE  Invalid Authenticode Signature.
  54
  55 **/
  56 BOOLEAN
  57 EFIAPI
  58 AuthenticodeVerify (
  59   IN  CONST UINT8  *AuthData,
  60   IN  UINTN        DataSize,
  61   IN  CONST UINT8  *TrustedCert,
  62   IN  UINTN        CertSize,
  63   IN  CONST UINT8  *ImageHash,
  64   IN  UINTN        HashSize
  65   )
  66 {
  67   BOOLEAN      Status;
  68   PKCS7        *Pkcs7;
  69   CONST UINT8  *OrigAuthData;
  70   UINT8        *SpcIndirectDataContent;
  71   UINT8        Asn1Byte;
  72   UINTN        ContentSize;
  73
  74   //
  75   // Check input parameters.
  76   //
  77   if ((AuthData == NULL) || (TrustedCert == NULL) || (ImageHash == NULL)) {
  78     return FALSE;
  79   }
  80
  81   if ((DataSize > INT_MAX) || (CertSize > INT_MAX) || (HashSize > INT_MAX)) {
  82     return FALSE;
  83   }
  84
  85   Status       = FALSE;
  86   Pkcs7        = NULL;
  87   OrigAuthData = AuthData;
  88
  89   //
  90   // Retrieve & Parse PKCS#7 Data (DER encoding) from Authenticode Signature
  91   //
  92   Pkcs7 = d2i_PKCS7 (NULL, &AuthData, (int)DataSize);
  93   if (Pkcs7 == NULL) {
  94     goto _Exit;
  95   }
  96
  97   //
  98   // Check if it's PKCS#7 Signed Data (for Authenticode Scenario)
  99   //
 100   if (!PKCS7_type_is_signed (Pkcs7)) {
 101     goto _Exit;
 102   }
 103
 104   //
 105   // NOTE: OpenSSL PKCS7 Decoder didn't work for Authenticode-format signed data due to
 106   //       some authenticode-specific structure. Use opaque ASN.1 string to retrieve
 107   //       PKCS#7 ContentInfo here.
 108   //
 109   SpcIndirectDataContent = (UINT8 *)(Pkcs7->d.sign->contents->d.other->value.asn1_string->data);
 110
 111   //
 112   // Retrieve the SEQUENCE data size from ASN.1-encoded SpcIndirectDataContent.
 113   //
 114   Asn1Byte = *(SpcIndirectDataContent + 1);
 115
 116   if ((Asn1Byte & 0x80) == 0) {
 117     //
 118     // Short Form of Length Encoding
 119     //
 120     ContentSize = (UINTN) (Asn1Byte & 0x7F);
 121     //
 122     // Skip the SEQUENCE Tag;
 123     //
 124     SpcIndirectDataContent += 2;
 125   } else if ((Asn1Byte & 0x82) == 0x82) {
 126     //
 127     // Long Form of Length Encoding, only support two bytes.
 128     //
 129     ContentSize  = (UINTN) (*(SpcIndirectDataContent + 2));
 130     ContentSize = (ContentSize << 8) + (UINTN)(*(SpcIndirectDataContent + 3));
 131     //
 132     // Skip the SEQUENCE Tag;
 133     //
 134     SpcIndirectDataContent += 4;
 135   } else {
 136     goto _Exit;
 137   }
 138
 139   //
 140   // Compare the original file hash value to the digest retrieve from SpcIndirectDataContent
 141   // defined in Authenticode
 142   // NOTE: Need to double-check HashLength here!
 143   //
 144   if (CompareMem (SpcIndirectDataContent + ContentSize - HashSize, ImageHash, HashSize) != 0) {
 145     //
 146     // Un-matched PE/COFF Hash Value
 147     //
 148     goto _Exit;
 149   }
 150
 151   //
 152   // Verifies the PKCS#7 Signed Data in PE/COFF Authenticode Signature
 153   //
 154   Status = (BOOLEAN) Pkcs7Verify (OrigAuthData, DataSize, TrustedCert, CertSize, SpcIndirectDataContent, ContentSize);
 155
 156 _Exit:
 157   //
 158   // Release Resources
 159   //
 160   PKCS7_free (Pkcs7);
 161
 162   return Status;
 163 }