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
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
|
/** @file
Authenticode Portable Executable Signature Verification which does not provide
real capabilities.
Copyright (c) 2024, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "InternalCryptLib.h"
#include <mbedtls/pkcs7.h>
//
// OID ASN.1 Value for SPC_INDIRECT_DATA_OBJID
//
GLOBAL_REMOVE_IF_UNREFERENCED const 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".
Return FALSE to indicate this interface is not supported.
@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 FALSE This interface is not supported.
**/
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;
CONST UINT8 *OrigAuthData;
UINT8 *SpcIndirectDataContent;
UINT8 Asn1Byte;
UINTN ContentSize;
CONST UINT8 *SpcIndirectDataOid;
UINT8 *Ptr;
UINT8 *End;
INT32 Len;
UINTN ObjLen;
OrigAuthData = AuthData;
//
// Check input parameters.
//
if ((AuthData == NULL) || (TrustedCert == NULL) || (ImageHash == NULL)) {
return FALSE;
}
if ((DataSize > INT_MAX) || (CertSize > INT_MAX) || (HashSize > INT_MAX)) {
return FALSE;
}
if (DataSize <= HashSize) {
return FALSE;
}
Ptr = (UINT8 *)(UINTN)AuthData;
Len = (UINT32)DataSize;
End = Ptr + Len;
// ContentInfo
if (mbedtls_asn1_get_tag (&Ptr, End, &ObjLen, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE) != 0) {
return FALSE;
}
// ContentType
if (mbedtls_asn1_get_tag (&Ptr, End, &ObjLen, MBEDTLS_ASN1_OID) != 0) {
return FALSE;
}
Ptr += ObjLen;
// content
if (mbedtls_asn1_get_tag (&Ptr, End, &ObjLen, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_CONTEXT_SPECIFIC) != 0) {
return FALSE;
}
End = Ptr + ObjLen;
// signedData
if (mbedtls_asn1_get_tag (&Ptr, End, &ObjLen, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE) != 0) {
return FALSE;
}
// version
if (mbedtls_asn1_get_tag (&Ptr, End, &ObjLen, MBEDTLS_ASN1_INTEGER) != 0) {
return FALSE;
}
Ptr += ObjLen;
// digestAlgo
if (mbedtls_asn1_get_tag (&Ptr, End, &ObjLen, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SET) != 0) {
return FALSE;
}
Ptr += ObjLen;
// encapContentInfo
if (mbedtls_asn1_get_tag (&Ptr, End, &ObjLen, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE) != 0) {
return FALSE;
}
End = Ptr + ObjLen;
// eContentType
if (mbedtls_asn1_get_tag (&Ptr, End, &ObjLen, MBEDTLS_ASN1_OID) != 0) {
return FALSE;
}
Status = FALSE;
SpcIndirectDataOid = Ptr;
if ((ObjLen != sizeof (mSpcIndirectOidValue)) ||
(CompareMem (
SpcIndirectDataOid,
mSpcIndirectOidValue,
sizeof (mSpcIndirectOidValue)
) != 0))
{
//
// Un-matched SPC_INDIRECT_DATA_OBJID.
//
goto _Exit;
}
Ptr += ObjLen;
// eContent
if (mbedtls_asn1_get_tag (&Ptr, End, &ObjLen, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_CONTEXT_SPECIFIC) != 0) {
return FALSE;
}
SpcIndirectDataContent = Ptr;
//
// 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 (ContentSize < HashSize) {
return FALSE;
}
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:
return Status;
}
|
