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 - 2015, 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 // OID ASN.1 Value for SPC_INDIRECT_DATA_OBJID
31 //
32 UINT8 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 **/
62 BOOLEAN
63 EFIAPI
AuthenticodeVerify(IN CONST UINT8 * AuthData,IN UINTN DataSize,IN CONST UINT8 * TrustedCert,IN UINTN CertSize,IN CONST UINT8 * ImageHash,IN UINTN HashSize)64 AuthenticodeVerify (
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