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
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
|
/** @file
PKCS#7 SignedData Verification Wrapper Implementation over OpenSSL.
Caution: This module requires additional review when modified.
This library will have external input - signature (e.g. UEFI Authenticated
Variable). It may by input in SMM mode.
This external input must be validated carefully to avoid security issue like
buffer overflow, integer overflow.
WrapPkcs7Data(), Pkcs7GetSigners(), Pkcs7Verify() will get UEFI Authenticated
Variable and will do basic check for data structure.
Copyright (c) 2009 - 2012, 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>
UINT8 mOidValue[9] = { 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x07, 0x02 };
/**
Verification callback function to override any existing callbacks in OpenSSL
for intermediate certificate supports.
@param[in] Status Original status before calling this callback.
@param[in] Context X509 store context.
@retval 1 Current X509 certificate is verified successfully.
@retval 0 Verification failed.
**/
int
X509VerifyCb (
IN int Status,
IN X509_STORE_CTX *Context
)
{
X509_OBJECT *Obj;
INTN Error;
INTN Index;
INTN Count;
Obj = NULL;
Error = (INTN) X509_STORE_CTX_get_error (Context);
//
// X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT and X509_V_ERR_UNABLE_TO_GET_ISSUER_
// CERT_LOCALLY mean a X509 certificate is not self signed and its issuer
// can not be found in X509_verify_cert of X509_vfy.c.
// In order to support intermediate certificate node, we override the
// errors if the certification is obtained from X509 store, i.e. it is
// a trusted ceritifcate node that is enrolled by user.
// Besides,X509_V_ERR_CERT_UNTRUSTED and X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE
// are also ignored to enable such feature.
//
if ((Error == X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT) ||
(Error == X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY)) {
Obj = (X509_OBJECT *) malloc (sizeof (X509_OBJECT));
if (Obj == NULL) {
return 0;
}
Obj->type = X509_LU_X509;
Obj->data.x509 = Context->current_cert;
CRYPTO_w_lock (CRYPTO_LOCK_X509_STORE);
if (X509_OBJECT_retrieve_match (Context->ctx->objs, Obj)) {
Status = 1;
} else {
//
// If any certificate in the chain is enrolled as trusted certificate,
// pass the certificate verification.
//
if (Error == X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY) {
Count = (INTN) sk_X509_num (Context->chain);
for (Index = 0; Index < Count; Index++) {
Obj->data.x509 = sk_X509_value (Context->chain, (int) Index);
if (X509_OBJECT_retrieve_match (Context->ctx->objs, Obj)) {
Status = 1;
break;
}
}
}
}
CRYPTO_w_unlock (CRYPTO_LOCK_X509_STORE);
}
if ((Error == X509_V_ERR_CERT_UNTRUSTED) ||
(Error == X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE)) {
Status = 1;
}
if (Obj != NULL) {
OPENSSL_free (Obj);
}
return Status;
}
/**
Check input P7Data is a wrapped ContentInfo structure or not. If not construct
a new structure to wrap P7Data.
Caution: This function may receive untrusted input.
UEFI Authenticated Variable is external input, so this function will do basic
check for PKCS#7 data structure.
@param[in] P7Data Pointer to the PKCS#7 message to verify.
@param[in] P7Length Length of the PKCS#7 message in bytes.
@param[out] WrapFlag If TRUE P7Data is a ContentInfo structure, otherwise
return FALSE.
@param[out] WrapData If return status of this function is TRUE:
1) when WrapFlag is TRUE, pointer to P7Data.
2) when WrapFlag is FALSE, pointer to a new ContentInfo
structure. It's caller's responsibility to free this
buffer.
@param[out] WrapDataSize Length of ContentInfo structure in bytes.
@retval TRUE The operation is finished successfully.
@retval FALSE The operation is failed due to lack of resources.
**/
BOOLEAN
WrapPkcs7Data (
IN CONST UINT8 *P7Data,
IN UINTN P7Length,
OUT BOOLEAN *WrapFlag,
OUT UINT8 **WrapData,
OUT UINTN *WrapDataSize
)
{
BOOLEAN Wrapped;
UINT8 *SignedData;
//
// Check whether input P7Data is a wrapped ContentInfo structure or not.
//
Wrapped = FALSE;
if ((P7Data[4] == 0x06) && (P7Data[5] == 0x09)) {
if (CompareMem (P7Data + 6, mOidValue, sizeof (mOidValue)) == 0) {
if ((P7Data[15] == 0xA0) && (P7Data[16] == 0x82)) {
Wrapped = TRUE;
}
}
}
if (Wrapped) {
*WrapData = (UINT8 *) P7Data;
*WrapDataSize = P7Length;
} else {
//
// Wrap PKCS#7 signeddata to a ContentInfo structure - add a header in 19 bytes.
//
*WrapDataSize = P7Length + 19;
*WrapData = malloc (*WrapDataSize);
if (*WrapData == NULL) {
*WrapFlag = Wrapped;
return FALSE;
}
SignedData = *WrapData;
//
// Part1: 0x30, 0x82.
//
SignedData[0] = 0x30;
SignedData[1] = 0x82;
//
// Part2: Length1 = P7Length + 19 - 4, in big endian.
//
SignedData[2] = (UINT8) (((UINT16) (*WrapDataSize - 4)) >> 8);
SignedData[3] = (UINT8) (((UINT16) (*WrapDataSize - 4)) & 0xff);
//
// Part3: 0x06, 0x09.
//
SignedData[4] = 0x06;
SignedData[5] = 0x09;
//
// Part4: OID value -- 0x2A 0x86 0x48 0x86 0xF7 0x0D 0x01 0x07 0x02.
//
CopyMem (SignedData + 6, mOidValue, sizeof (mOidValue));
//
// Part5: 0xA0, 0x82.
//
SignedData[15] = 0xA0;
SignedData[16] = 0x82;
//
// Part6: Length2 = P7Length, in big endian.
//
SignedData[17] = (UINT8) (((UINT16) P7Length) >> 8);
SignedData[18] = (UINT8) (((UINT16) P7Length) & 0xff);
//
// Part7: P7Data.
//
CopyMem (SignedData + 19, P7Data, P7Length);
}
*WrapFlag = Wrapped;
return TRUE;
}
/**
Pop single certificate from STACK_OF(X509).
If X509Stack, Cert, or CertSize is NULL, then return FALSE.
@param[in] X509Stack Pointer to a X509 stack object.
@param[out] Cert Pointer to a X509 certificate.
@param[out] CertSize Length of output X509 certificate in bytes.
@retval TRUE The X509 stack pop succeeded.
@retval FALSE The pop operation failed.
**/
BOOLEAN
X509PopCertificate (
IN VOID *X509Stack,
OUT UINT8 **Cert,
OUT UINTN *CertSize
)
{
BIO *CertBio;
X509 *X509Cert;
STACK_OF(X509) *CertStack;
BOOLEAN Status;
INT32 Result;
INT32 Length;
VOID *Buffer;
Status = FALSE;
if ((X509Stack == NULL) || (Cert == NULL) || (CertSize == NULL)) {
return Status;
}
CertStack = (STACK_OF(X509) *) X509Stack;
X509Cert = sk_X509_pop (CertStack);
if (X509Cert == NULL) {
return Status;
}
Buffer = NULL;
CertBio = BIO_new (BIO_s_mem ());
if (CertBio == NULL) {
return Status;
}
Result = i2d_X509_bio (CertBio, X509Cert);
if (Result == 0) {
goto _Exit;
}
Length = ((BUF_MEM *) CertBio->ptr)->length;
if (Length <= 0) {
goto _Exit;
}
Buffer = malloc (Length);
if (Buffer == NULL) {
goto _Exit;
}
Result = BIO_read (CertBio, Buffer, Length);
if (Result != Length) {
goto _Exit;
}
*Cert = Buffer;
*CertSize = Length;
Status = TRUE;
_Exit:
BIO_free (CertBio);
if (!Status && (Buffer != NULL)) {
free (Buffer);
}
return Status;
}
/**
Get the signer's certificates from PKCS#7 signed data as described in "PKCS #7:
Cryptographic Message Syntax Standard". The input signed data could be wrapped
in a ContentInfo structure.
If P7Data, CertStack, StackLength, TrustedCert or CertLength is NULL, then
return FALSE. If P7Length overflow, then return FAlSE.
Caution: This function may receive untrusted input.
UEFI Authenticated Variable is external input, so this function will do basic
check for PKCS#7 data structure.
@param[in] P7Data Pointer to the PKCS#7 message to verify.
@param[in] P7Length Length of the PKCS#7 message in bytes.
@param[out] CertStack Pointer to Signer's certificates retrieved from P7Data.
It's caller's responsiblity to free the buffer.
@param[out] StackLength Length of signer's certificates in bytes.
@param[out] TrustedCert Pointer to a trusted certificate from Signer's certificates.
It's caller's responsiblity to free the buffer.
@param[out] CertLength Length of the trusted certificate in bytes.
@retval TRUE The operation is finished successfully.
@retval FALSE Error occurs during the operation.
**/
BOOLEAN
EFIAPI
Pkcs7GetSigners (
IN CONST UINT8 *P7Data,
IN UINTN P7Length,
OUT UINT8 **CertStack,
OUT UINTN *StackLength,
OUT UINT8 **TrustedCert,
OUT UINTN *CertLength
)
{
PKCS7 *Pkcs7;
BOOLEAN Status;
UINT8 *SignedData;
UINT8 *Temp;
UINTN SignedDataSize;
BOOLEAN Wrapped;
STACK_OF(X509) *Stack;
UINT8 Index;
UINT8 *CertBuf;
UINT8 *OldBuf;
UINTN BufferSize;
UINTN OldSize;
UINT8 *SingleCert;
UINTN SingleCertSize;
if ((P7Data == NULL) || (CertStack == NULL) || (StackLength == NULL) ||
(TrustedCert == NULL) || (CertLength == NULL) || (P7Length > INT_MAX)) {
return FALSE;
}
Status = WrapPkcs7Data (P7Data, P7Length, &Wrapped, &SignedData, &SignedDataSize);
if (!Status) {
return Status;
}
Status = FALSE;
Pkcs7 = NULL;
Stack = NULL;
CertBuf = NULL;
OldBuf = NULL;
SingleCert = NULL;
//
// Retrieve PKCS#7 Data (DER encoding)
//
if (SignedDataSize > INT_MAX) {
goto _Exit;
}
Temp = SignedData;
Pkcs7 = d2i_PKCS7 (NULL, (const unsigned char **) &Temp, (int) SignedDataSize);
if (Pkcs7 == NULL) {
goto _Exit;
}
//
// Check if it's PKCS#7 Signed Data (for Authenticode Scenario)
//
if (!PKCS7_type_is_signed (Pkcs7)) {
goto _Exit;
}
Stack = PKCS7_get0_signers(Pkcs7, NULL, PKCS7_BINARY);
if (Stack == NULL) {
goto _Exit;
}
//
// Convert CertStack to buffer in following format:
// UINT8 CertNumber;
// UINT32 Cert1Length;
// UINT8 Cert1[];
// UINT32 Cert2Length;
// UINT8 Cert2[];
// ...
// UINT32 CertnLength;
// UINT8 Certn[];
//
BufferSize = sizeof (UINT8);
OldSize = BufferSize;
for (Index = 0; ; Index++) {
Status = X509PopCertificate (Stack, &SingleCert, &SingleCertSize);
if (!Status) {
break;
}
OldSize = BufferSize;
OldBuf = CertBuf;
BufferSize = OldSize + SingleCertSize + sizeof (UINT32);
CertBuf = malloc (BufferSize);
if (CertBuf == NULL) {
goto _Exit;
}
if (OldBuf != NULL) {
CopyMem (CertBuf, OldBuf, OldSize);
free (OldBuf);
OldBuf = NULL;
}
WriteUnaligned32 ((UINT32 *) (CertBuf + OldSize), (UINT32) SingleCertSize);
CopyMem (CertBuf + OldSize + sizeof (UINT32), SingleCert, SingleCertSize);
free (SingleCert);
SingleCert = NULL;
}
if (CertBuf != NULL) {
//
// Update CertNumber.
//
CertBuf[0] = Index;
*CertLength = BufferSize - OldSize - sizeof (UINT32);
*TrustedCert = malloc (*CertLength);
if (*TrustedCert == NULL) {
goto _Exit;
}
CopyMem (*TrustedCert, CertBuf + OldSize + sizeof (UINT32), *CertLength);
*CertStack = CertBuf;
*StackLength = BufferSize;
Status = TRUE;
}
_Exit:
//
// Release Resources
//
if (!Wrapped) {
free (SignedData);
}
if (Pkcs7 != NULL) {
PKCS7_free (Pkcs7);
}
if (Stack != NULL) {
sk_X509_pop_free(Stack, X509_free);
}
if (SingleCert != NULL) {
free (SingleCert);
}
if (!Status && (CertBuf != NULL)) {
free (CertBuf);
*CertStack = NULL;
}
if (OldBuf != NULL) {
free (OldBuf);
}
return Status;
}
/**
Wrap function to use free() to free allocated memory for certificates.
@param[in] Certs Pointer to the certificates to be freed.
**/
VOID
EFIAPI
Pkcs7FreeSigners (
IN UINT8 *Certs
)
{
if (Certs == NULL) {
return;
}
free (Certs);
}
/**
Verifies the validility of a PKCS#7 signed data as described in "PKCS #7:
Cryptographic Message Syntax Standard". The input signed data could be wrapped
in a ContentInfo structure.
If P7Data, TrustedCert or InData is NULL, then return FALSE.
If P7Length, CertLength or DataLength overflow, then return FAlSE.
Caution: This function may receive untrusted input.
UEFI Authenticated Variable is external input, so this function will do basic
check for PKCS#7 data structure.
@param[in] P7Data Pointer to the PKCS#7 message to verify.
@param[in] P7Length Length of the PKCS#7 message in bytes.
@param[in] TrustedCert Pointer to a trusted/root certificate encoded in DER, which
is used for certificate chain verification.
@param[in] CertLength Length of the trusted certificate in bytes.
@param[in] InData Pointer to the content to be verified.
@param[in] DataLength Length of InData in bytes.
@retval TRUE The specified PKCS#7 signed data is valid.
@retval FALSE Invalid PKCS#7 signed data.
**/
BOOLEAN
EFIAPI
Pkcs7Verify (
IN CONST UINT8 *P7Data,
IN UINTN P7Length,
IN CONST UINT8 *TrustedCert,
IN UINTN CertLength,
IN CONST UINT8 *InData,
IN UINTN DataLength
)
{
PKCS7 *Pkcs7;
BIO *CertBio;
BIO *DataBio;
BOOLEAN Status;
X509 *Cert;
X509_STORE *CertStore;
UINT8 *SignedData;
UINT8 *Temp;
UINTN SignedDataSize;
BOOLEAN Wrapped;
//
// Check input parameters.
//
if (P7Data == NULL || TrustedCert == NULL || InData == NULL ||
P7Length > INT_MAX || CertLength > INT_MAX || DataLength > INT_MAX) {
return FALSE;
}
Pkcs7 = NULL;
CertBio = NULL;
DataBio = NULL;
Cert = NULL;
CertStore = NULL;
//
// Register & Initialize necessary digest algorithms for PKCS#7 Handling
//
if (EVP_add_digest (EVP_md5 ()) == 0) {
return FALSE;
}
if (EVP_add_digest (EVP_sha1 ()) == 0) {
return FALSE;
}
if (EVP_add_digest (EVP_sha256 ()) == 0) {
return FALSE;
}
if (EVP_add_digest_alias (SN_sha1WithRSAEncryption, SN_sha1WithRSA) == 0) {
return FALSE;
}
Status = WrapPkcs7Data (P7Data, P7Length, &Wrapped, &SignedData, &SignedDataSize);
if (!Status) {
return Status;
}
Status = FALSE;
//
// Retrieve PKCS#7 Data (DER encoding)
//
if (SignedDataSize > INT_MAX) {
goto _Exit;
}
Temp = SignedData;
Pkcs7 = d2i_PKCS7 (NULL, (const unsigned char **) &Temp, (int) SignedDataSize);
if (Pkcs7 == NULL) {
goto _Exit;
}
//
// Check if it's PKCS#7 Signed Data (for Authenticode Scenario)
//
if (!PKCS7_type_is_signed (Pkcs7)) {
goto _Exit;
}
//
// Read DER-encoded root certificate and Construct X509 Certificate
//
CertBio = BIO_new (BIO_s_mem ());
BIO_write (CertBio, TrustedCert, (int)CertLength);
if (CertBio == NULL) {
goto _Exit;
}
Cert = d2i_X509_bio (CertBio, NULL);
if (Cert == NULL) {
goto _Exit;
}
//
// Setup X509 Store for trusted certificate
//
CertStore = X509_STORE_new ();
if (CertStore == NULL) {
goto _Exit;
}
if (!(X509_STORE_add_cert (CertStore, Cert))) {
goto _Exit;
}
//
// Register customized X509 verification callback function to support
// trusted intermediate certificate anchor.
//
CertStore->verify_cb = X509VerifyCb;
//
// For generic PKCS#7 handling, InData may be NULL if the content is present
// in PKCS#7 structure. So ignore NULL checking here.
//
DataBio = BIO_new (BIO_s_mem ());
BIO_write (DataBio, InData, (int)DataLength);
//
// Verifies the PKCS#7 signedData structure
//
Status = (BOOLEAN) PKCS7_verify (Pkcs7, NULL, CertStore, DataBio, NULL, PKCS7_BINARY);
_Exit:
//
// Release Resources
//
BIO_free (DataBio);
BIO_free (CertBio);
X509_free (Cert);
X509_STORE_free (CertStore);
PKCS7_free (Pkcs7);
if (!Wrapped) {
OPENSSL_free (SignedData);
}
return Status;
}
|