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
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
|
/** @file
Implement image verification services for secure boot service in UEFI2.3.1.
Copyright (c) 2009 - 2011, 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 "DxeImageVerificationLib.h"
EFI_IMAGE_OPTIONAL_HEADER_PTR_UNION mNtHeader;
UINTN mImageSize;
UINT32 mPeCoffHeaderOffset;
UINT8 mImageDigest[MAX_DIGEST_SIZE];
UINTN mImageDigestSize;
EFI_IMAGE_DATA_DIRECTORY *mSecDataDir = NULL;
UINT8 *mImageBase = NULL;
EFI_GUID mCertType;
//
// Notify string for authorization UI.
//
CHAR16 mNotifyString1[MAX_NOTIFY_STRING_LEN] = L"Image verification pass but not found in authorized database!";
CHAR16 mNotifyString2[MAX_NOTIFY_STRING_LEN] = L"Launch this image anyway? (Yes/Defer/No)";
//
// Public Exponent of RSA Key.
//
CONST UINT8 mRsaE[] = { 0x01, 0x00, 0x01 };
//
// OID ASN.1 Value for Hash Algorithms
//
UINT8 mHashOidValue[] = {
0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x02, 0x05, // OBJ_md5
0x2B, 0x0E, 0x03, 0x02, 0x1A, // OBJ_sha1
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04, // OBJ_sha224
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, // OBJ_sha256
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02, // OBJ_sha384
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, // OBJ_sha512
};
HASH_TABLE mHash[] = {
{ L"SHA1", 20, &mHashOidValue[8], 5, Sha1GetContextSize, Sha1Init, Sha1Update, Sha1Final },
{ L"SHA224", 28, &mHashOidValue[13], 9, NULL, NULL, NULL, NULL },
{ L"SHA256", 32, &mHashOidValue[22], 9, Sha256GetContextSize,Sha256Init, Sha256Update, Sha256Final},
{ L"SHA384", 48, &mHashOidValue[31], 9, NULL, NULL, NULL, NULL },
{ L"SHA512", 64, &mHashOidValue[40], 9, NULL, NULL, NULL, NULL }
};
/**
Get the image type.
@param[in] File This is a pointer to the device path of the file that is
being dispatched.
@return UINT32 Image Type
**/
UINT32
GetImageType (
IN CONST EFI_DEVICE_PATH_PROTOCOL *File
)
{
EFI_STATUS Status;
EFI_HANDLE DeviceHandle;
EFI_DEVICE_PATH_PROTOCOL *TempDevicePath;
EFI_BLOCK_IO_PROTOCOL *BlockIo;
//
// First check to see if File is from a Firmware Volume
//
DeviceHandle = NULL;
TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *)File;
Status = gBS->LocateDevicePath (
&gEfiFirmwareVolume2ProtocolGuid,
&TempDevicePath,
&DeviceHandle
);
if (!EFI_ERROR (Status)) {
Status = gBS->OpenProtocol (
DeviceHandle,
&gEfiFirmwareVolume2ProtocolGuid,
NULL,
NULL,
NULL,
EFI_OPEN_PROTOCOL_TEST_PROTOCOL
);
if (!EFI_ERROR (Status)) {
return IMAGE_FROM_FV;
}
}
//
// Next check to see if File is from a Block I/O device
//
DeviceHandle = NULL;
TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *)File;
Status = gBS->LocateDevicePath (
&gEfiBlockIoProtocolGuid,
&TempDevicePath,
&DeviceHandle
);
if (!EFI_ERROR (Status)) {
BlockIo = NULL;
Status = gBS->OpenProtocol (
DeviceHandle,
&gEfiBlockIoProtocolGuid,
(VOID **) &BlockIo,
NULL,
NULL,
EFI_OPEN_PROTOCOL_GET_PROTOCOL
);
if (!EFI_ERROR (Status) && BlockIo != NULL) {
if (BlockIo->Media != NULL) {
if (BlockIo->Media->RemovableMedia) {
//
// Block I/O is present and specifies the media is removable
//
return IMAGE_FROM_REMOVABLE_MEDIA;
} else {
//
// Block I/O is present and specifies the media is not removable
//
return IMAGE_FROM_FIXED_MEDIA;
}
}
}
}
//
// File is not in a Firmware Volume or on a Block I/O device, so check to see if
// the device path supports the Simple File System Protocol.
//
DeviceHandle = NULL;
TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *)File;
Status = gBS->LocateDevicePath (
&gEfiSimpleFileSystemProtocolGuid,
&TempDevicePath,
&DeviceHandle
);
if (!EFI_ERROR (Status)) {
//
// Simple File System is present without Block I/O, so assume media is fixed.
//
return IMAGE_FROM_FIXED_MEDIA;
}
//
// File is not from an FV, Block I/O or Simple File System, so the only options
// left are a PCI Option ROM and a Load File Protocol such as a PXE Boot from a NIC.
//
TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *)File;
while (!IsDevicePathEndType (TempDevicePath)) {
switch (DevicePathType (TempDevicePath)) {
case MEDIA_DEVICE_PATH:
if (DevicePathSubType (TempDevicePath) == MEDIA_RELATIVE_OFFSET_RANGE_DP) {
return IMAGE_FROM_OPTION_ROM;
}
break;
case MESSAGING_DEVICE_PATH:
if (DevicePathSubType(TempDevicePath) == MSG_MAC_ADDR_DP) {
return IMAGE_FROM_REMOVABLE_MEDIA;
}
break;
default:
break;
}
TempDevicePath = NextDevicePathNode (TempDevicePath);
}
return IMAGE_UNKNOWN;
}
/**
Caculate hash of Pe/Coff image based on the authenticode image hashing in
PE/COFF Specification 8.0 Appendix A
@param[in] HashAlg Hash algorithm type.
@retval TRUE Successfully hash image.
@retval FALSE Fail in hash image.
**/
BOOLEAN
HashPeImage (
IN UINT32 HashAlg
)
{
BOOLEAN Status;
UINT16 Magic;
EFI_IMAGE_SECTION_HEADER *Section;
VOID *HashCtx;
UINTN CtxSize;
UINT8 *HashBase;
UINTN HashSize;
UINTN SumOfBytesHashed;
EFI_IMAGE_SECTION_HEADER *SectionHeader;
UINTN Index;
UINTN Pos;
UINTN SumOfSectionBytes;
EFI_IMAGE_SECTION_HEADER *SectionCache;
HashCtx = NULL;
SectionHeader = NULL;
Status = FALSE;
if ((HashAlg != HASHALG_SHA1) && (HashAlg != HASHALG_SHA256)) {
return FALSE;
}
//
// Initialize context of hash.
//
ZeroMem (mImageDigest, MAX_DIGEST_SIZE);
if (HashAlg == HASHALG_SHA1) {
mImageDigestSize = SHA1_DIGEST_SIZE;
mCertType = gEfiCertSha1Guid;
} else if (HashAlg == HASHALG_SHA256) {
mImageDigestSize = SHA256_DIGEST_SIZE;
mCertType = gEfiCertSha256Guid;
} else {
return FALSE;
}
CtxSize = mHash[HashAlg].GetContextSize();
HashCtx = AllocatePool (CtxSize);
if (HashCtx == NULL) {
return FALSE;
}
// 1. Load the image header into memory.
// 2. Initialize a SHA hash context.
Status = mHash[HashAlg].HashInit(HashCtx);
if (!Status) {
goto Done;
}
//
// Measuring PE/COFF Image Header;
// But CheckSum field and SECURITY data directory (certificate) are excluded
//
Magic = mNtHeader.Pe32->OptionalHeader.Magic;
//
// 3. Calculate the distance from the base of the image header to the image checksum address.
// 4. Hash the image header from its base to beginning of the image checksum.
//
HashBase = mImageBase;
if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
//
// Use PE32 offset.
//
HashSize = (UINTN) ((UINT8 *) (&mNtHeader.Pe32->OptionalHeader.CheckSum) - HashBase);
} else if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC) {
//
// Use PE32+ offset.
//
HashSize = (UINTN) ((UINT8 *) (&mNtHeader.Pe32Plus->OptionalHeader.CheckSum) - HashBase);
} else {
//
// Invalid header magic number.
//
Status = FALSE;
goto Done;
}
Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
if (!Status) {
goto Done;
}
//
// 5. Skip over the image checksum (it occupies a single ULONG).
// 6. Get the address of the beginning of the Cert Directory.
// 7. Hash everything from the end of the checksum to the start of the Cert Directory.
//
if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
//
// Use PE32 offset.
//
HashBase = (UINT8 *) &mNtHeader.Pe32->OptionalHeader.CheckSum + sizeof (UINT32);
HashSize = (UINTN) ((UINT8 *) (&mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - HashBase);
} else {
//
// Use PE32+ offset.
//
HashBase = (UINT8 *) &mNtHeader.Pe32Plus->OptionalHeader.CheckSum + sizeof (UINT32);
HashSize = (UINTN) ((UINT8 *) (&mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY]) - HashBase);
}
Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
if (!Status) {
goto Done;
}
//
// 8. Skip over the Cert Directory. (It is sizeof(IMAGE_DATA_DIRECTORY) bytes.)
// 9. Hash everything from the end of the Cert Directory to the end of image header.
//
if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
//
// Use PE32 offset
//
HashBase = (UINT8 *) &mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1];
HashSize = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders - (UINTN) ((UINT8 *) (&mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1]) - mImageBase);
} else {
//
// Use PE32+ offset.
//
HashBase = (UINT8 *) &mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1];
HashSize = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders - (UINTN) ((UINT8 *) (&mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY + 1]) - mImageBase);
}
Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
if (!Status) {
goto Done;
}
//
// 10. Set the SUM_OF_BYTES_HASHED to the size of the header.
//
if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
//
// Use PE32 offset.
//
SumOfBytesHashed = mNtHeader.Pe32->OptionalHeader.SizeOfHeaders;
} else {
//
// Use PE32+ offset
//
SumOfBytesHashed = mNtHeader.Pe32Plus->OptionalHeader.SizeOfHeaders;
}
Section = (EFI_IMAGE_SECTION_HEADER *) (
mImageBase +
mPeCoffHeaderOffset +
sizeof (UINT32) +
sizeof (EFI_IMAGE_FILE_HEADER) +
mNtHeader.Pe32->FileHeader.SizeOfOptionalHeader
);
SectionCache = Section;
for (Index = 0, SumOfSectionBytes = 0; Index < mNtHeader.Pe32->FileHeader.NumberOfSections; Index++, SectionCache++) {
SumOfSectionBytes += SectionCache->SizeOfRawData;
}
//
// Sanity check for file corruption. Sections raw data size should be smaller
// than Image Size.
//
if (SumOfSectionBytes >= mImageSize) {
Status = FALSE;
goto Done;
}
//
// 11. Build a temporary table of pointers to all the IMAGE_SECTION_HEADER
// structures in the image. The 'NumberOfSections' field of the image
// header indicates how big the table should be. Do not include any
// IMAGE_SECTION_HEADERs in the table whose 'SizeOfRawData' field is zero.
//
SectionHeader = (EFI_IMAGE_SECTION_HEADER *) AllocateZeroPool (sizeof (EFI_IMAGE_SECTION_HEADER) * mNtHeader.Pe32->FileHeader.NumberOfSections);
if (SectionHeader == NULL) {
Status = FALSE;
goto Done;
}
//
// 12. Using the 'PointerToRawData' in the referenced section headers as
// a key, arrange the elements in the table in ascending order. In other
// words, sort the section headers according to the disk-file offset of
// the section.
//
for (Index = 0; Index < mNtHeader.Pe32->FileHeader.NumberOfSections; Index++) {
Pos = Index;
while ((Pos > 0) && (Section->PointerToRawData < SectionHeader[Pos - 1].PointerToRawData)) {
CopyMem (&SectionHeader[Pos], &SectionHeader[Pos - 1], sizeof (EFI_IMAGE_SECTION_HEADER));
Pos--;
}
CopyMem (&SectionHeader[Pos], Section, sizeof (EFI_IMAGE_SECTION_HEADER));
Section += 1;
}
//
// 13. Walk through the sorted table, bring the corresponding section
// into memory, and hash the entire section (using the 'SizeOfRawData'
// field in the section header to determine the amount of data to hash).
// 14. Add the section's 'SizeOfRawData' to SUM_OF_BYTES_HASHED .
// 15. Repeat steps 13 and 14 for all the sections in the sorted table.
//
for (Index = 0; Index < mNtHeader.Pe32->FileHeader.NumberOfSections; Index++) {
Section = &SectionHeader[Index];
if (Section->SizeOfRawData == 0) {
continue;
}
HashBase = mImageBase + Section->PointerToRawData;
HashSize = (UINTN) Section->SizeOfRawData;
Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
if (!Status) {
goto Done;
}
SumOfBytesHashed += HashSize;
}
//
// 16. If the file size is greater than SUM_OF_BYTES_HASHED, there is extra
// data in the file that needs to be added to the hash. This data begins
// at file offset SUM_OF_BYTES_HASHED and its length is:
// FileSize - (CertDirectory->Size)
//
if (mImageSize > SumOfBytesHashed) {
HashBase = mImageBase + SumOfBytesHashed;
if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
//
// Use PE32 offset.
//
HashSize = (UINTN)(
mImageSize -
mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY].Size -
SumOfBytesHashed);
} else {
//
// Use PE32+ offset.
//
HashSize = (UINTN)(
mImageSize -
mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY].Size -
SumOfBytesHashed);
}
Status = mHash[HashAlg].HashUpdate(HashCtx, HashBase, HashSize);
if (!Status) {
goto Done;
}
}
Status = mHash[HashAlg].HashFinal(HashCtx, mImageDigest);
Done:
if (HashCtx != NULL) {
FreePool (HashCtx);
}
if (SectionHeader != NULL) {
FreePool (SectionHeader);
}
return Status;
}
/**
Recognize the Hash algorithm in PE/COFF Authenticode and caculate hash of
Pe/Coff image based on the authenticode image hashing in PE/COFF Specification
8.0 Appendix A
@retval EFI_UNSUPPORTED Hash algorithm is not supported.
@retval EFI_SUCCESS Hash successfully.
**/
EFI_STATUS
HashPeImageByType (
VOID
)
{
UINT8 Index;
WIN_CERTIFICATE_EFI_PKCS *PkcsCertData;
PkcsCertData = (WIN_CERTIFICATE_EFI_PKCS *) (mImageBase + mSecDataDir->VirtualAddress);
for (Index = 0; Index < HASHALG_MAX; Index++) {
//
// Check the Hash algorithm in PE/COFF Authenticode.
// According to PKCS#7 Definition:
// SignedData ::= SEQUENCE {
// version Version,
// digestAlgorithms DigestAlgorithmIdentifiers,
// contentInfo ContentInfo,
// .... }
// The DigestAlgorithmIdentifiers can be used to determine the hash algorithm in PE/COFF hashing
// This field has the fixed offset (+32) in final Authenticode ASN.1 data.
//
if (CompareMem (PkcsCertData->CertData + 32, mHash[Index].OidValue, mHash[Index].OidLength) == 0) {
break;
}
}
if (Index == HASHALG_MAX) {
return EFI_UNSUPPORTED;
}
//
// HASH PE Image based on Hash algorithm in PE/COFF Authenticode.
//
if (!HashPeImage(Index)) {
return EFI_UNSUPPORTED;
}
return EFI_SUCCESS;
}
/**
Returns the size of a given image execution info table in bytes.
This function returns the size, in bytes, of the image execution info table specified by
ImageExeInfoTable. If ImageExeInfoTable is NULL, then 0 is returned.
@param ImageExeInfoTable A pointer to a image execution info table structure.
@retval 0 If ImageExeInfoTable is NULL.
@retval Others The size of a image execution info table in bytes.
**/
UINTN
GetImageExeInfoTableSize (
EFI_IMAGE_EXECUTION_INFO_TABLE *ImageExeInfoTable
)
{
UINTN Index;
EFI_IMAGE_EXECUTION_INFO *ImageExeInfoItem;
UINTN TotalSize;
if (ImageExeInfoTable == NULL) {
return 0;
}
ImageExeInfoItem = (EFI_IMAGE_EXECUTION_INFO *) ((UINT8 *) ImageExeInfoTable + sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE));
TotalSize = sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE);
for (Index = 0; Index < ImageExeInfoTable->NumberOfImages; Index++) {
TotalSize += ReadUnaligned32 ((UINT32 *) &ImageExeInfoItem->InfoSize);
ImageExeInfoItem = (EFI_IMAGE_EXECUTION_INFO *) ((UINT8 *) ImageExeInfoItem + ReadUnaligned32 ((UINT32 *) &ImageExeInfoItem->InfoSize));
}
return TotalSize;
}
/**
Create an Image Execution Information Table entry and add it to system configuration table.
@param[in] Action Describes the action taken by the firmware regarding this image.
@param[in] Name Input a null-terminated, user-friendly name.
@param[in] DevicePath Input device path pointer.
@param[in] Signature Input signature info in EFI_SIGNATURE_LIST data structure.
@param[in] SignatureSize Size of signature.
**/
VOID
AddImageExeInfo (
IN EFI_IMAGE_EXECUTION_ACTION Action,
IN CHAR16 *Name OPTIONAL,
IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath,
IN EFI_SIGNATURE_LIST *Signature OPTIONAL,
IN UINTN SignatureSize
)
{
EFI_IMAGE_EXECUTION_INFO_TABLE *ImageExeInfoTable;
EFI_IMAGE_EXECUTION_INFO_TABLE *NewImageExeInfoTable;
EFI_IMAGE_EXECUTION_INFO *ImageExeInfoEntry;
UINTN ImageExeInfoTableSize;
UINTN NewImageExeInfoEntrySize;
UINTN NameStringLen;
UINTN DevicePathSize;
ImageExeInfoTable = NULL;
NewImageExeInfoTable = NULL;
ImageExeInfoEntry = NULL;
NameStringLen = 0;
if (DevicePath == NULL) {
return ;
}
if (Name != NULL) {
NameStringLen = StrSize (Name);
}
ImageExeInfoTable = NULL;
EfiGetSystemConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID**)&ImageExeInfoTable);
if (ImageExeInfoTable != NULL) {
//
// The table has been found!
// We must enlarge the table to accmodate the new exe info entry.
//
ImageExeInfoTableSize = GetImageExeInfoTableSize (ImageExeInfoTable);
} else {
//
// Not Found!
// We should create a new table to append to the configuration table.
//
ImageExeInfoTableSize = sizeof (EFI_IMAGE_EXECUTION_INFO_TABLE);
}
DevicePathSize = GetDevicePathSize (DevicePath);
NewImageExeInfoEntrySize = sizeof (EFI_IMAGE_EXECUTION_INFO) + NameStringLen + DevicePathSize + SignatureSize;
NewImageExeInfoTable = (EFI_IMAGE_EXECUTION_INFO_TABLE *) AllocateRuntimePool (ImageExeInfoTableSize + NewImageExeInfoEntrySize);
if (NewImageExeInfoTable == NULL) {
return ;
}
if (ImageExeInfoTable != NULL) {
CopyMem (NewImageExeInfoTable, ImageExeInfoTable, ImageExeInfoTableSize);
} else {
NewImageExeInfoTable->NumberOfImages = 0;
}
NewImageExeInfoTable->NumberOfImages++;
ImageExeInfoEntry = (EFI_IMAGE_EXECUTION_INFO *) ((UINT8 *) NewImageExeInfoTable + ImageExeInfoTableSize);
//
// Update new item's infomation.
//
WriteUnaligned32 ((UINT32 *) &ImageExeInfoEntry->Action, Action);
WriteUnaligned32 ((UINT32 *) &ImageExeInfoEntry->InfoSize, (UINT32) NewImageExeInfoEntrySize);
if (Name != NULL) {
CopyMem ((UINT8 *) &ImageExeInfoEntry->InfoSize + sizeof (UINT32), Name, NameStringLen);
}
CopyMem (
(UINT8 *) &ImageExeInfoEntry->InfoSize + sizeof (UINT32) + NameStringLen,
DevicePath,
DevicePathSize
);
if (Signature != NULL) {
CopyMem (
(UINT8 *) &ImageExeInfoEntry->InfoSize + sizeof (UINT32) + NameStringLen + DevicePathSize,
Signature,
SignatureSize
);
}
//
// Update/replace the image execution table.
//
gBS->InstallConfigurationTable (&gEfiImageSecurityDatabaseGuid, (VOID *) NewImageExeInfoTable);
//
// Free Old table data!
//
if (ImageExeInfoTable != NULL) {
FreePool (ImageExeInfoTable);
}
}
/**
Discover if the UEFI image is authorized by user's policy setting.
@param[in] Policy Specify platform's policy setting.
@retval EFI_ACCESS_DENIED Image is not allowed to run.
@retval EFI_SECURITY_VIOLATION Image is deferred.
@retval EFI_SUCCESS Image is authorized to run.
**/
EFI_STATUS
ImageAuthorization (
IN UINT32 Policy
)
{
EFI_STATUS Status;
EFI_INPUT_KEY Key;
Status = EFI_ACCESS_DENIED;
switch (Policy) {
case QUERY_USER_ON_SECURITY_VIOLATION:
do {
CreatePopUp (EFI_LIGHTGRAY | EFI_BACKGROUND_BLUE, &Key, mNotifyString1, mNotifyString2, NULL);
if (Key.UnicodeChar == L'Y' || Key.UnicodeChar == L'y') {
Status = EFI_SUCCESS;
break;
} else if (Key.UnicodeChar == L'N' || Key.UnicodeChar == L'n') {
Status = EFI_ACCESS_DENIED;
break;
} else if (Key.UnicodeChar == L'D' || Key.UnicodeChar == L'd') {
Status = EFI_SECURITY_VIOLATION;
break;
}
} while (TRUE);
break;
case ALLOW_EXECUTE_ON_SECURITY_VIOLATION:
Status = EFI_SUCCESS;
break;
case DEFER_EXECUTE_ON_SECURITY_VIOLATION:
Status = EFI_SECURITY_VIOLATION;
break;
case DENY_EXECUTE_ON_SECURITY_VIOLATION:
Status = EFI_ACCESS_DENIED;
break;
}
return Status;
}
/**
Check whether signature is in specified database.
@param[in] VariableName Name of database variable that is searched in.
@param[in] Signature Pointer to signature that is searched for.
@param[in] CertType Pointer to hash algrithom.
@param[in] SignatureSize Size of Signature.
@return TRUE Found the signature in the variable database.
@return FALSE Not found the signature in the variable database.
**/
BOOLEAN
IsSignatureFoundInDatabase (
IN CHAR16 *VariableName,
IN UINT8 *Signature,
IN EFI_GUID *CertType,
IN UINTN SignatureSize
)
{
EFI_STATUS Status;
EFI_SIGNATURE_LIST *CertList;
EFI_SIGNATURE_DATA *Cert;
UINTN DataSize;
UINT8 *Data;
UINTN Index;
UINTN CertCount;
BOOLEAN IsFound;
//
// Read signature database variable.
//
IsFound = FALSE;
Data = NULL;
DataSize = 0;
Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
if (Status != EFI_BUFFER_TOO_SMALL) {
return FALSE;
}
Data = (UINT8 *) AllocateZeroPool (DataSize);
if (Data == NULL) {
return FALSE;
}
Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, Data);
if (EFI_ERROR (Status)) {
goto Done;
}
//
// Enumerate all signature data in SigDB to check if executable's signature exists.
//
CertList = (EFI_SIGNATURE_LIST *) Data;
while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) {
CertCount = (CertList->SignatureListSize - CertList->SignatureHeaderSize) / CertList->SignatureSize;
Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
if ((CertList->SignatureSize == sizeof(EFI_SIGNATURE_DATA) - 1 + SignatureSize) && (CompareGuid(&CertList->SignatureType, CertType))) {
for (Index = 0; Index < CertCount; Index++) {
if (CompareMem (Cert->SignatureData, Signature, SignatureSize) == 0) {
//
// Find the signature in database.
//
IsFound = TRUE;
break;
}
Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize);
}
if (IsFound) {
break;
}
}
DataSize -= CertList->SignatureListSize;
CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
}
Done:
if (Data != NULL) {
FreePool (Data);
}
return IsFound;
}
/**
Verify certificate in WIN_CERT_TYPE_PKCS_SIGNED_DATA format .
@retval EFI_SUCCESS Image pass verification.
@retval EFI_SECURITY_VIOLATION Image fail verification.
@retval EFI_OUT_OF_RESOURCE Fail to allocate memory.
**/
EFI_STATUS
VerifyCertPkcsSignedData (
VOID
)
{
EFI_STATUS Status;
BOOLEAN VerifyStatus;
WIN_CERTIFICATE_EFI_PKCS *PkcsCertData;
EFI_SIGNATURE_LIST *CertList;
EFI_SIGNATURE_DATA *Cert;
UINTN DataSize;
UINT8 *KekData;
UINT8 *DbData;
UINT8 *RootCert;
UINTN RootCertSize;
UINTN Index;
UINTN CertCount;
KekData = NULL;
DbData = NULL;
CertList = NULL;
Cert = NULL;
RootCert = NULL;
RootCertSize = 0;
VerifyStatus = FALSE;
PkcsCertData = (WIN_CERTIFICATE_EFI_PKCS *) (mImageBase + mSecDataDir->VirtualAddress);
//
// 1: Find certificate from KEK database and try to verify authenticode struct.
//
DataSize = 0;
Status = gRT->GetVariable (EFI_KEY_EXCHANGE_KEY_NAME, &gEfiGlobalVariableGuid, NULL, &DataSize, NULL);
if (Status == EFI_BUFFER_TOO_SMALL) {
KekData = (UINT8 *)AllocateZeroPool (DataSize);
if (KekData == NULL) {
return EFI_OUT_OF_RESOURCES;
}
Status = gRT->GetVariable (EFI_KEY_EXCHANGE_KEY_NAME, &gEfiGlobalVariableGuid, NULL, &DataSize, (VOID *)KekData);
if (EFI_ERROR (Status)) {
goto Done;
}
//
// Find Cert Enrolled in KEK database to verify the signature in pkcs7 signed data.
//
CertList = (EFI_SIGNATURE_LIST *) KekData;
while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) {
if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
for (Index = 0; Index < CertCount; Index++) {
//
// Iterate each Signature Data Node within this CertList for a verify
//
RootCert = Cert->SignatureData;
RootCertSize = CertList->SignatureSize;
//
// Call AuthenticodeVerify library to Verify Authenticode struct.
//
VerifyStatus = AuthenticodeVerify (
PkcsCertData->CertData,
mSecDataDir->Size - sizeof(PkcsCertData->Hdr),
RootCert,
RootCertSize,
mImageDigest,
mImageDigestSize
);
if (VerifyStatus) {
goto Done;
}
Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize);
}
}
DataSize -= CertList->SignatureListSize;
CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
}
}
//
// 2: Find certificate from DB database and try to verify authenticode struct.
//
DataSize = 0;
Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
if (Status == EFI_BUFFER_TOO_SMALL) {
DbData = (UINT8 *)AllocateZeroPool (DataSize);
if (DbData == NULL) {
goto Done;
}
Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, (VOID *)DbData);
if (EFI_ERROR (Status)) {
goto Done;
}
//
// Find Cert Enrolled in DB database to verify the signature in pkcs7 signed data.
//
CertList = (EFI_SIGNATURE_LIST *) DbData;
while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) {
if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
for (Index = 0; Index < CertCount; Index++) {
//
// Iterate each Signature Data Node within this CertList for a verify
//
RootCert = Cert->SignatureData;
RootCertSize = CertList->SignatureSize;
//
// Call AuthenticodeVerify library to Verify Authenticode struct.
//
VerifyStatus = AuthenticodeVerify (
PkcsCertData->CertData,
mSecDataDir->Size - sizeof(PkcsCertData->Hdr),
RootCert,
RootCertSize,
mImageDigest,
mImageDigestSize
);
if (VerifyStatus) {
goto Done;
}
Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize);
}
}
DataSize -= CertList->SignatureListSize;
CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
}
}
Done:
if (KekData != NULL) {
FreePool (KekData);
}
if (DbData != NULL) {
FreePool (DbData);
}
if (VerifyStatus) {
return EFI_SUCCESS;
} else {
return EFI_SECURITY_VIOLATION;
}
}
/**
Verify certificate in WIN_CERTIFICATE_UEFI_GUID format.
@retval EFI_SUCCESS Image pass verification.
@retval EFI_SECURITY_VIOLATION Image fail verification.
@retval other error value
**/
EFI_STATUS
VerifyCertUefiGuid (
VOID
)
{
BOOLEAN Status;
WIN_CERTIFICATE_UEFI_GUID *EfiCert;
EFI_SIGNATURE_LIST *KekList;
EFI_SIGNATURE_DATA *KekItem;
EFI_CERT_BLOCK_RSA_2048_SHA256 *CertBlock;
VOID *Rsa;
UINTN KekCount;
UINTN Index;
UINTN KekDataSize;
BOOLEAN IsFound;
EFI_STATUS Result;
EfiCert = NULL;
KekList = NULL;
KekItem = NULL;
CertBlock = NULL;
Rsa = NULL;
Status = FALSE;
IsFound = FALSE;
KekDataSize = 0;
EfiCert = (WIN_CERTIFICATE_UEFI_GUID *) (mImageBase + mSecDataDir->VirtualAddress);
CertBlock = (EFI_CERT_BLOCK_RSA_2048_SHA256 *) EfiCert->CertData;
if (!CompareGuid (&EfiCert->CertType, &gEfiCertTypeRsa2048Sha256Guid)) {
//
// Invalid Certificate Data Type.
//
return EFI_SECURITY_VIOLATION;
}
//
// Get KEK database variable data size
//
Result = gRT->GetVariable (EFI_KEY_EXCHANGE_KEY_NAME, &gEfiGlobalVariableGuid, NULL, &KekDataSize, NULL);
if (Result != EFI_BUFFER_TOO_SMALL) {
return EFI_SECURITY_VIOLATION;
}
//
// Get KEK database variable.
//
KekList = GetEfiGlobalVariable (EFI_KEY_EXCHANGE_KEY_NAME);
if (KekList == NULL) {
return EFI_SECURITY_VIOLATION;
}
//
// Enumerate all Kek items in this list to verify the variable certificate data.
// If anyone is authenticated successfully, it means the variable is correct!
//
while ((KekDataSize > 0) && (KekDataSize >= KekList->SignatureListSize)) {
if (CompareGuid (&KekList->SignatureType, &gEfiCertRsa2048Guid)) {
KekItem = (EFI_SIGNATURE_DATA *) ((UINT8 *) KekList + sizeof (EFI_SIGNATURE_LIST) + KekList->SignatureHeaderSize);
KekCount = (KekList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - KekList->SignatureHeaderSize) / KekList->SignatureSize;
for (Index = 0; Index < KekCount; Index++) {
if (CompareMem (KekItem->SignatureData, CertBlock->PublicKey, EFI_CERT_TYPE_RSA2048_SIZE) == 0) {
IsFound = TRUE;
break;
}
KekItem = (EFI_SIGNATURE_DATA *) ((UINT8 *) KekItem + KekList->SignatureSize);
}
}
KekDataSize -= KekList->SignatureListSize;
KekList = (EFI_SIGNATURE_LIST *) ((UINT8 *) KekList + KekList->SignatureListSize);
}
if (!IsFound) {
//
// Signed key is not a trust one.
//
goto Done;
}
//
// Now, we found the corresponding security policy.
// Verify the data payload.
//
Rsa = RsaNew ();
if (Rsa == NULL) {
Status = FALSE;
goto Done;
}
//
// Set RSA Key Components.
// NOTE: Only N and E are needed to be set as RSA public key for signature verification.
//
Status = RsaSetKey (Rsa, RsaKeyN, CertBlock->PublicKey, EFI_CERT_TYPE_RSA2048_SIZE);
if (!Status) {
goto Done;
}
Status = RsaSetKey (Rsa, RsaKeyE, mRsaE, sizeof (mRsaE));
if (!Status) {
goto Done;
}
//
// Verify the signature.
//
Status = RsaPkcs1Verify (
Rsa,
mImageDigest,
mImageDigestSize,
CertBlock->Signature,
EFI_CERT_TYPE_RSA2048_SHA256_SIZE
);
Done:
if (KekList != NULL) {
FreePool (KekList);
}
if (Rsa != NULL ) {
RsaFree (Rsa);
}
if (Status) {
return EFI_SUCCESS;
} else {
return EFI_SECURITY_VIOLATION;
}
}
/**
Provide verification service for signed images, which include both signature validation
and platform policy control. For signature types, both UEFI WIN_CERTIFICATE_UEFI_GUID and
MSFT Authenticode type signatures are supported.
In this implementation, only verify external executables when in USER MODE.
Executables from FV is bypass, so pass in AuthenticationStatus is ignored.
@param[in] AuthenticationStatus
This is the authentication status returned from the security
measurement services for the input file.
@param[in] File This is a pointer to the device path of the file that is
being dispatched. This will optionally be used for logging.
@param[in] FileBuffer File buffer matches the input file device path.
@param[in] FileSize Size of File buffer matches the input file device path.
@retval EFI_SUCCESS The file specified by File did authenticate, and the
platform policy dictates that the DXE Core may use File.
@retval EFI_INVALID_PARAMETER Input argument is incorrect.
@retval EFI_OUT_RESOURCE Fail to allocate memory.
@retval EFI_SECURITY_VIOLATION The file specified by File did not authenticate, and
the platform policy dictates that File should be placed
in the untrusted state. A file may be promoted from
the untrusted to the trusted state at a future time
with a call to the Trust() DXE Service.
@retval EFI_ACCESS_DENIED The file specified by File did not authenticate, and
the platform policy dictates that File should not be
used for any purpose.
**/
EFI_STATUS
EFIAPI
DxeImageVerificationHandler (
IN UINT32 AuthenticationStatus,
IN CONST EFI_DEVICE_PATH_PROTOCOL *File,
IN VOID *FileBuffer,
IN UINTN FileSize
)
{
EFI_STATUS Status;
UINT16 Magic;
EFI_IMAGE_DOS_HEADER *DosHdr;
EFI_STATUS VerifyStatus;
UINT8 *SetupMode;
EFI_SIGNATURE_LIST *SignatureList;
UINTN SignatureListSize;
EFI_SIGNATURE_DATA *Signature;
EFI_IMAGE_EXECUTION_ACTION Action;
WIN_CERTIFICATE *WinCertificate;
UINT32 Policy;
UINT8 *SecureBootEnable;
if (File == NULL) {
return EFI_INVALID_PARAMETER;
}
SignatureList = NULL;
SignatureListSize = 0;
WinCertificate = NULL;
Action = EFI_IMAGE_EXECUTION_AUTH_UNTESTED;
Status = EFI_ACCESS_DENIED;
//
// Check the image type and get policy setting.
//
switch (GetImageType (File)) {
case IMAGE_FROM_FV:
Policy = ALWAYS_EXECUTE;
break;
case IMAGE_FROM_OPTION_ROM:
Policy = PcdGet32 (PcdOptionRomImageVerificationPolicy);
break;
case IMAGE_FROM_REMOVABLE_MEDIA:
Policy = PcdGet32 (PcdRemovableMediaImageVerificationPolicy);
break;
case IMAGE_FROM_FIXED_MEDIA:
Policy = PcdGet32 (PcdFixedMediaImageVerificationPolicy);
break;
default:
Policy = DENY_EXECUTE_ON_SECURITY_VIOLATION;
break;
}
//
// If policy is always/never execute, return directly.
//
if (Policy == ALWAYS_EXECUTE) {
return EFI_SUCCESS;
} else if (Policy == NEVER_EXECUTE) {
return EFI_ACCESS_DENIED;
}
SecureBootEnable = GetVariable (EFI_SECURE_BOOT_ENABLE_NAME, &gEfiSecureBootEnableDisableGuid);
//
// Skip verification if SecureBootEnable variable doesn't exist.
//
if (SecureBootEnable == NULL) {
return EFI_SUCCESS;
}
//
// Skip verification if SecureBootEnable is disabled.
//
if (*SecureBootEnable == SECURE_BOOT_DISABLE) {
FreePool (SecureBootEnable);
return EFI_SUCCESS;
}
SetupMode = GetEfiGlobalVariable (EFI_SETUP_MODE_NAME);
//
// SetupMode doesn't exist means no AuthVar driver is dispatched,
// skip verification.
//
if (SetupMode == NULL) {
return EFI_SUCCESS;
}
//
// If platform is in SETUP MODE, skip verification.
//
if (*SetupMode == SETUP_MODE) {
FreePool (SetupMode);
return EFI_SUCCESS;
}
//
// Read the Dos header.
//
if (FileBuffer == NULL) {
FreePool (SetupMode);
return EFI_INVALID_PARAMETER;
}
mImageBase = (UINT8 *) FileBuffer;
mImageSize = FileSize;
DosHdr = (EFI_IMAGE_DOS_HEADER *) (mImageBase);
if (DosHdr->e_magic == EFI_IMAGE_DOS_SIGNATURE) {
//
// DOS image header is present,
// so read the PE header after the DOS image header.
//
mPeCoffHeaderOffset = DosHdr->e_lfanew;
} else {
mPeCoffHeaderOffset = 0;
}
//
// Check PE/COFF image.
//
mNtHeader.Pe32 = (EFI_IMAGE_NT_HEADERS32 *) (mImageBase + mPeCoffHeaderOffset);
if (mNtHeader.Pe32->Signature != EFI_IMAGE_NT_SIGNATURE) {
//
// It is not a valid Pe/Coff file.
//
return EFI_ACCESS_DENIED;
}
Magic = mNtHeader.Pe32->OptionalHeader.Magic;
if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
//
// Use PE32 offset.
//
mSecDataDir = (EFI_IMAGE_DATA_DIRECTORY *)&mNtHeader.Pe32->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY];
} else if (Magic == EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC) {
//
// Use PE32+ offset.
//
mSecDataDir = (EFI_IMAGE_DATA_DIRECTORY *)&mNtHeader.Pe32Plus->OptionalHeader.DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_SECURITY];
} else {
//
// Invalid header magic number.
//
Status = EFI_INVALID_PARAMETER;
goto Done;
}
if (mSecDataDir->VirtualAddress >= mImageSize) {
//
// Sanity check to see if this file is corrupted.
//
Status = EFI_INVALID_PARAMETER;
goto Done;
}
if (mSecDataDir->Size == 0) {
//
// This image is not signed.
//
Action = EFI_IMAGE_EXECUTION_AUTH_UNTESTED;
Status = EFI_ACCESS_DENIED;
goto Done;
}
//
// Verify signature of executables.
//
WinCertificate = (WIN_CERTIFICATE *) (mImageBase + mSecDataDir->VirtualAddress);
switch (WinCertificate->wCertificateType) {
case WIN_CERT_TYPE_EFI_GUID:
//
// Verify UEFI GUID type.
//
if (!HashPeImage (HASHALG_SHA256)) {
goto Done;
}
VerifyStatus = VerifyCertUefiGuid ();
break;
case WIN_CERT_TYPE_PKCS_SIGNED_DATA:
//
// Verify Pkcs signed data type.
//
Status = HashPeImageByType();
if (EFI_ERROR(Status)) {
goto Done;
}
VerifyStatus = VerifyCertPkcsSignedData ();
//
// For image verification against enrolled certificate(root or intermediate),
// no need to check image's hash in the allowed database.
//
if (!EFI_ERROR (VerifyStatus)) {
return EFI_SUCCESS;
}
default:
return EFI_ACCESS_DENIED;
}
//
// Get image hash value as executable's signature.
//
SignatureListSize = sizeof (EFI_SIGNATURE_LIST) + sizeof (EFI_SIGNATURE_DATA) - 1 + mImageDigestSize;
SignatureList = (EFI_SIGNATURE_LIST *) AllocateZeroPool (SignatureListSize);
if (SignatureList == NULL) {
Status = EFI_OUT_OF_RESOURCES;
goto Done;
}
SignatureList->SignatureHeaderSize = 0;
SignatureList->SignatureListSize = (UINT32) SignatureListSize;
SignatureList->SignatureSize = (UINT32) mImageDigestSize;
CopyMem (&SignatureList->SignatureType, &mCertType, sizeof (EFI_GUID));
Signature = (EFI_SIGNATURE_DATA *) ((UINT8 *) SignatureList + sizeof (EFI_SIGNATURE_LIST));
CopyMem (Signature->SignatureData, mImageDigest, mImageDigestSize);
//
// Signature database check after verification.
//
if (EFI_ERROR (VerifyStatus)) {
//
// Verification failure.
//
Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FAILED;
Status = EFI_ACCESS_DENIED;
} else if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, Signature->SignatureData, &mCertType, mImageDigestSize)) {
//
// Executable signature verification passes, but is found in forbidden signature database.
//
Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FOUND;
Status = EFI_ACCESS_DENIED;
} else if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, Signature->SignatureData, &mCertType, mImageDigestSize)) {
//
// Executable signature is found in authorized signature database.
//
Status = EFI_SUCCESS;
} else {
//
// Executable signature verification passes, but cannot be found in authorized signature database.
// Get platform policy to determine the action.
//
Action = EFI_IMAGE_EXECUTION_AUTH_SIG_PASSED;
Status = ImageAuthorization (Policy);
}
Done:
if (Status != EFI_SUCCESS) {
//
// Policy decides to defer or reject the image; add its information in image executable information table.
//
AddImageExeInfo (Action, NULL, File, SignatureList, SignatureListSize);
}
if (SignatureList != NULL) {
FreePool (SignatureList);
}
FreePool (SetupMode);
return Status;
}
/**
When VariableWriteArchProtocol install, create "SecureBoot" variable.
@param[in] Event Event whose notification function is being invoked.
@param[in] Context Pointer to the notification function's context.
**/
VOID
EFIAPI
VariableWriteCallBack (
IN EFI_EVENT Event,
IN VOID *Context
)
{
UINT8 SecureBootMode;
UINT8 *SecureBootModePtr;
EFI_STATUS Status;
VOID *ProtocolPointer;
Status = gBS->LocateProtocol (&gEfiVariableWriteArchProtocolGuid, NULL, &ProtocolPointer);
if (EFI_ERROR (Status)) {
return;
}
//
// Check whether "SecureBoot" variable exists.
// If this library is built-in, it means firmware has capability to perform
// driver signing verification.
//
SecureBootModePtr = GetEfiGlobalVariable (EFI_SECURE_BOOT_MODE_NAME);
if (SecureBootModePtr == NULL) {
SecureBootMode = SECURE_BOOT_MODE_DISABLE;
//
// Authenticated variable driver will update "SecureBoot" depending on SetupMode variable.
//
gRT->SetVariable (
EFI_SECURE_BOOT_MODE_NAME,
&gEfiGlobalVariableGuid,
EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_NON_VOLATILE,
sizeof (UINT8),
&SecureBootMode
);
} else {
FreePool (SecureBootModePtr);
}
}
/**
Register security measurement handler.
@param ImageHandle ImageHandle of the loaded driver.
@param SystemTable Pointer to the EFI System Table.
@retval EFI_SUCCESS The handlers were registered successfully.
**/
EFI_STATUS
EFIAPI
DxeImageVerificationLibConstructor (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
VOID *Registration;
//
// Register callback function upon VariableWriteArchProtocol.
//
EfiCreateProtocolNotifyEvent (
&gEfiVariableWriteArchProtocolGuid,
TPL_CALLBACK,
VariableWriteCallBack,
NULL,
&Registration
);
return RegisterSecurityHandler (
DxeImageVerificationHandler,
EFI_AUTH_OPERATION_VERIFY_IMAGE | EFI_AUTH_OPERATION_IMAGE_REQUIRED
);
}
|