1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
|
/** @file
Authenticode Portable Executable Signature Verification over OpenSSL.
Caution: This module requires additional review when modified.
This library will have external input - signature (e.g. PE/COFF Authenticode).
This external input must be validated carefully to avoid security issue like
buffer overflow, integer overflow.
AuthenticodeVerify() will get PE/COFF Authenticode and will do basic check for
data structure.
Copyright (c) 2011 - 2019, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include "InternalCryptLib.h"
#include <openssl/objects.h>
#include <openssl/x509.h>
#include <openssl/pkcs7.h>
//
// OID ASN.1 Value for SPC_INDIRECT_DATA_OBJID
//
UINT8 mSpcIndirectOidValue[] = {
0x2B, 0x06, 0x01, 0x04, 0x01, 0x82, 0x37, 0x02, 0x01, 0x04
};
/**
Verifies the validity of a PE/COFF Authenticode Signature as described in "Windows
Authenticode Portable Executable Signature Format".
If AuthData is NULL, then return FALSE.
If ImageHash is NULL, then return FALSE.
Caution: This function may receive untrusted input.
PE/COFF Authenticode is external input, so this function will do basic check for
Authenticode data structure.
@param[in] AuthData Pointer to the Authenticode Signature retrieved from signed
PE/COFF image to be verified.
@param[in] DataSize Size of the Authenticode Signature in bytes.
@param[in] TrustedCert Pointer to a trusted/root certificate encoded in DER, which
is used for certificate chain verification.
@param[in] CertSize Size of the trusted certificate in bytes.
@param[in] ImageHash Pointer to the original image file hash value. The procedure
for calculating the image hash value is described in Authenticode
specification.
@param[in] HashSize Size of Image hash value in bytes.
@retval TRUE The specified Authenticode Signature is valid.
@retval FALSE Invalid Authenticode Signature.
**/
BOOLEAN
EFIAPI
AuthenticodeVerify (
IN CONST UINT8 *AuthData,
IN UINTN DataSize,
IN CONST UINT8 *TrustedCert,
IN UINTN CertSize,
IN CONST UINT8 *ImageHash,
IN UINTN HashSize
)
{
BOOLEAN Status;
PKCS7 *Pkcs7;
CONST UINT8 *Temp;
CONST UINT8 *OrigAuthData;
UINT8 *SpcIndirectDataContent;
UINT8 Asn1Byte;
UINTN ContentSize;
CONST UINT8 *SpcIndirectDataOid;
//
// Check input parameters.
//
if ((AuthData == NULL) || (TrustedCert == NULL) || (ImageHash == NULL)) {
return FALSE;
}
if ((DataSize > INT_MAX) || (CertSize > INT_MAX) || (HashSize > INT_MAX)) {
return FALSE;
}
Status = FALSE;
Pkcs7 = NULL;
OrigAuthData = AuthData;
//
// Retrieve & Parse PKCS#7 Data (DER encoding) from Authenticode Signature
//
Temp = AuthData;
Pkcs7 = d2i_PKCS7 (NULL, &Temp, (int)DataSize);
if (Pkcs7 == NULL) {
goto _Exit;
}
//
// Check if it's PKCS#7 Signed Data (for Authenticode Scenario)
//
if (!PKCS7_type_is_signed (Pkcs7) || PKCS7_get_detached (Pkcs7)) {
goto _Exit;
}
//
// NOTE: OpenSSL PKCS7 Decoder didn't work for Authenticode-format signed data due to
// some authenticode-specific structure. Use opaque ASN.1 string to retrieve
// PKCS#7 ContentInfo here.
//
SpcIndirectDataOid = OBJ_get0_data(Pkcs7->d.sign->contents->type);
if (OBJ_length(Pkcs7->d.sign->contents->type) != sizeof(mSpcIndirectOidValue) ||
CompareMem (
SpcIndirectDataOid,
mSpcIndirectOidValue,
sizeof (mSpcIndirectOidValue)
) != 0) {
//
// Un-matched SPC_INDIRECT_DATA_OBJID.
//
goto _Exit;
}
SpcIndirectDataContent = (UINT8 *)(Pkcs7->d.sign->contents->d.other->value.asn1_string->data);
//
// Retrieve the SEQUENCE data size from ASN.1-encoded SpcIndirectDataContent.
//
Asn1Byte = *(SpcIndirectDataContent + 1);
if ((Asn1Byte & 0x80) == 0) {
//
// Short Form of Length Encoding (Length < 128)
//
ContentSize = (UINTN) (Asn1Byte & 0x7F);
//
// Skip the SEQUENCE Tag;
//
SpcIndirectDataContent += 2;
} else if ((Asn1Byte & 0x81) == 0x81) {
//
// Long Form of Length Encoding (128 <= Length < 255, Single Octet)
//
ContentSize = (UINTN) (*(UINT8 *)(SpcIndirectDataContent + 2));
//
// Skip the SEQUENCE Tag;
//
SpcIndirectDataContent += 3;
} else if ((Asn1Byte & 0x82) == 0x82) {
//
// Long Form of Length Encoding (Length > 255, Two Octet)
//
ContentSize = (UINTN) (*(UINT8 *)(SpcIndirectDataContent + 2));
ContentSize = (ContentSize << 8) + (UINTN)(*(UINT8 *)(SpcIndirectDataContent + 3));
//
// Skip the SEQUENCE Tag;
//
SpcIndirectDataContent += 4;
} else {
goto _Exit;
}
//
// Compare the original file hash value to the digest retrieve from SpcIndirectDataContent
// defined in Authenticode
// NOTE: Need to double-check HashLength here!
//
if (CompareMem (SpcIndirectDataContent + ContentSize - HashSize, ImageHash, HashSize) != 0) {
//
// Un-matched PE/COFF Hash Value
//
goto _Exit;
}
//
// Verifies the PKCS#7 Signed Data in PE/COFF Authenticode Signature
//
Status = (BOOLEAN) Pkcs7Verify (OrigAuthData, DataSize, TrustedCert, CertSize, SpcIndirectDataContent, ContentSize);
_Exit:
//
// Release Resources
//
PKCS7_free (Pkcs7);
return Status;
}
|
