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 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     // Un-matched SPC_INDIRECT_DATA_OBJID.
 121     //
 122     goto _Exit;
 123   }
 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
 143   } else if ((Asn1Byte & 0x81) == 0x81) {
 144     //
 145     // Long Form of Length Encoding (128 <= Length < 255, Single Octet)
 146     //
 147     ContentSize = (UINTN) (*(UINT8 *)(SpcIndirectDataContent + 2));
 148     //
 149     // Skip the SEQUENCE Tag;
 150     //
 151     SpcIndirectDataContent += 3;
 152
 153   } else if ((Asn1Byte & 0x82) == 0x82) {
 154     //
 155     // Long Form of Length Encoding (Length > 255, Two Octet)
 156     //
 157     ContentSize = (UINTN) (*(UINT8 *)(SpcIndirectDataContent + 2));
 158     ContentSize = (ContentSize << 8) + (UINTN)(*(UINT8 *)(SpcIndirectDataContent + 3));
 159     //
 160     // Skip the SEQUENCE Tag;
 161     //
 162     SpcIndirectDataContent += 4;
 163
 164   } else {
 165     goto _Exit;
 166   }
 167
 168   //
 169   // Compare the original file hash value to the digest retrieve from SpcIndirectDataContent
 170   // defined in Authenticode
 171   // NOTE: Need to double-check HashLength here!
 172   //
 173   if (CompareMem (SpcIndirectDataContent + ContentSize - HashSize, ImageHash, HashSize) != 0) {
 174     //
 175     // Un-matched PE/COFF Hash Value
 176     //
 177     goto _Exit;
 178   }
 179
 180   //
 181   // Verifies the PKCS#7 Signed Data in PE/COFF Authenticode Signature
 182   //
 183   Status = (BOOLEAN) Pkcs7Verify (OrigAuthData, DataSize, TrustedCert, CertSize, SpcIndirectDataContent, ContentSize);
 184
 185 _Exit:
 186   //
 187   // Release Resources
 188   //
 189   PKCS7_free (Pkcs7);
 190
 191   return Status;
 192 }