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 - 2020, Intel Corporation. All rights reserved.<BR>
  13 SPDX-License-Identifier: BSD-2-Clause-Patent
  14
  15 **/
  16
  17 #include "InternalCryptLib.h"
  18
  19 #include <openssl/objects.h>
  20 #include <openssl/x509.h>
  21 #include <openssl/pkcs7.h>
  22
  23 //
  24 // OID ASN.1 Value for SPC_INDIRECT_DATA_OBJID
  25 //
  26 GLOBAL_REMOVE_IF_UNREFERENCED const UINT8  mSpcIndirectOidValue[] = {
  27   0x2B, 0x06, 0x01, 0x04, 0x01, 0x82, 0x37, 0x02, 0x01, 0x04
  28 };
  29
  30 /**
  31   Verifies the validity 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 procedure
  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  *Temp;
  70   CONST UINT8  *OrigAuthData;
  71   UINT8        *SpcIndirectDataContent;
  72   UINT8        Asn1Byte;
  73   UINTN        ContentSize;
  74   CONST UINT8  *SpcIndirectDataOid;
  75
  76   //
  77   // Check input parameters.
  78   //
  79   if ((AuthData == NULL) || (TrustedCert == NULL) || (ImageHash == NULL)) {
  80     return FALSE;
  81   }
  82
  83   if ((DataSize > INT_MAX) || (CertSize > INT_MAX) || (HashSize > INT_MAX)) {
  84     return FALSE;
  85   }
  86
  87   Status       = FALSE;
  88   Pkcs7        = NULL;
  89   OrigAuthData = AuthData;
  90
  91   //
  92   // Retrieve & Parse PKCS#7 Data (DER encoding) from Authenticode Signature
  93   //
  94   Temp  = AuthData;
  95   Pkcs7 = d2i_PKCS7 (NULL, &Temp, (int)DataSize);
  96   if (Pkcs7 == NULL) {
  97     goto _Exit;
  98   }
  99
 100   //
 101   // Check if it's PKCS#7 Signed Data (for Authenticode Scenario)
 102   //
 103   if (!PKCS7_type_is_signed (Pkcs7) || PKCS7_get_detached (Pkcs7)) {
 104     goto _Exit;
 105   }
 106
 107   //
 108   // NOTE: OpenSSL PKCS7 Decoder didn't work for Authenticode-format signed data due to
 109   //       some authenticode-specific structure. Use opaque ASN.1 string to retrieve
 110   //       PKCS#7 ContentInfo here.
 111   //
 112   SpcIndirectDataOid = OBJ_get0_data (Pkcs7->d.sign->contents->type);
 113   if ((OBJ_length (Pkcs7->d.sign->contents->type) != sizeof (mSpcIndirectOidValue)) ||
 114       (CompareMem (
 115          SpcIndirectDataOid,
 116          mSpcIndirectOidValue,
 117          sizeof (mSpcIndirectOidValue)
 118          ) != 0))
 119   {
 120     //
 121     // Un-matched SPC_INDIRECT_DATA_OBJID.
 122     //
 123     goto _Exit;
 124   }
 125
 126   SpcIndirectDataContent = (UINT8 *)(Pkcs7->d.sign->contents->d.other->value.asn1_string->data);
 127
 128   //
 129   // Retrieve the SEQUENCE data size from ASN.1-encoded SpcIndirectDataContent.
 130   //
 131   Asn1Byte = *(SpcIndirectDataContent + 1);
 132
 133   if ((Asn1Byte & 0x80) == 0) {
 134     //
 135     // Short Form of Length Encoding (Length < 128)
 136     //
 137     ContentSize = (UINTN)(Asn1Byte & 0x7F);
 138     //
 139     // Skip the SEQUENCE Tag;
 140     //
 141     SpcIndirectDataContent += 2;
 142   } else if ((Asn1Byte & 0x81) == 0x81) {
 143     //
 144     // Long Form of Length Encoding (128 <= Length < 255, Single Octet)
 145     //
 146     ContentSize = (UINTN)(*(UINT8 *)(SpcIndirectDataContent + 2));
 147     //
 148     // Skip the SEQUENCE Tag;
 149     //
 150     SpcIndirectDataContent += 3;
 151   } else if ((Asn1Byte & 0x82) == 0x82) {
 152     //
 153     // Long Form of Length Encoding (Length > 255, Two Octet)
 154     //
 155     ContentSize = (UINTN)(*(UINT8 *)(SpcIndirectDataContent + 2));
 156     ContentSize = (ContentSize << 8) + (UINTN)(*(UINT8 *)(SpcIndirectDataContent + 3));
 157     //
 158     // Skip the SEQUENCE Tag;
 159     //
 160     SpcIndirectDataContent += 4;
 161   } else {
 162     goto _Exit;
 163   }
 164
 165   //
 166   // Compare the original file hash value to the digest retrieve from SpcIndirectDataContent
 167   // defined in Authenticode
 168   // NOTE: Need to double-check HashLength here!
 169   //
 170   if (CompareMem (SpcIndirectDataContent + ContentSize - HashSize, ImageHash, HashSize) != 0) {
 171     //
 172     // Un-matched PE/COFF Hash Value
 173     //
 174     goto _Exit;
 175   }
 176
 177   //
 178   // Verifies the PKCS#7 Signed Data in PE/COFF Authenticode Signature
 179   //
 180   Status = (BOOLEAN)Pkcs7Verify (OrigAuthData, DataSize, TrustedCert, CertSize, SpcIndirectDataContent, ContentSize);
 181
 182 _Exit:
 183   //
 184   // Release Resources
 185   //
 186   PKCS7_free (Pkcs7);
 187
 188   return Status;
 189 }