1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright(c) 2016-20 Intel Corporation. */
3
4 #define _GNU_SOURCE
5 #include <assert.h>
6 #include <getopt.h>
7 #include <stdbool.h>
8 #include <stdint.h>
9 #include <stdio.h>
10 #include <stdlib.h>
11 #include <string.h>
12 #include <sys/stat.h>
13 #include <sys/types.h>
14 #include <unistd.h>
15 #include <openssl/err.h>
16 #include <openssl/pem.h>
17 #include "defines.h"
18 #include "main.h"
19
20 /*
21 * FIXME: OpenSSL 3.0 has deprecated some functions. For now just ignore
22 * the warnings.
23 */
24 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
25
26 struct q1q2_ctx {
27 BN_CTX *bn_ctx;
28 BIGNUM *m;
29 BIGNUM *s;
30 BIGNUM *q1;
31 BIGNUM *qr;
32 BIGNUM *q2;
33 };
34
35 static void free_q1q2_ctx(struct q1q2_ctx *ctx)
36 {
37 BN_CTX_free(ctx->bn_ctx);
38 BN_free(ctx->m);
39 BN_free(ctx->s);
40 BN_free(ctx->q1);
41 BN_free(ctx->qr);
42 BN_free(ctx->q2);
43 }
44
45 static bool alloc_q1q2_ctx(const uint8_t *s, const uint8_t *m,
46 struct q1q2_ctx *ctx)
47 {
48 ctx->bn_ctx = BN_CTX_new();
49 ctx->s = BN_bin2bn(s, SGX_MODULUS_SIZE, NULL);
50 ctx->m = BN_bin2bn(m, SGX_MODULUS_SIZE, NULL);
51 ctx->q1 = BN_new();
52 ctx->qr = BN_new();
53 ctx->q2 = BN_new();
54
55 if (!ctx->bn_ctx || !ctx->s || !ctx->m || !ctx->q1 || !ctx->qr ||
56 !ctx->q2) {
57 free_q1q2_ctx(ctx);
58 return false;
59 }
60
61 return true;
62 }
63
64 static void reverse_bytes(void *data, int length)
65 {
66 int i = 0;
67 int j = length - 1;
68 uint8_t temp;
69 uint8_t *ptr = data;
70
71 while (i < j) {
72 temp = ptr[i];
73 ptr[i] = ptr[j];
74 ptr[j] = temp;
75 i++;
76 j--;
77 }
78 }
79
80 static bool calc_q1q2(const uint8_t *s, const uint8_t *m, uint8_t *q1,
81 uint8_t *q2)
82 {
83 struct q1q2_ctx ctx;
84 int len;
85
86 if (!alloc_q1q2_ctx(s, m, &ctx)) {
87 fprintf(stderr, "Not enough memory for Q1Q2 calculation\n");
88 return false;
89 }
90
91 if (!BN_mul(ctx.q1, ctx.s, ctx.s, ctx.bn_ctx))
92 goto out;
93
94 if (!BN_div(ctx.q1, ctx.qr, ctx.q1, ctx.m, ctx.bn_ctx))
95 goto out;
96
97 if (BN_num_bytes(ctx.q1) > SGX_MODULUS_SIZE) {
98 fprintf(stderr, "Too large Q1 %d bytes\n",
99 BN_num_bytes(ctx.q1));
100 goto out;
101 }
102
103 if (!BN_mul(ctx.q2, ctx.s, ctx.qr, ctx.bn_ctx))
104 goto out;
105
106 if (!BN_div(ctx.q2, NULL, ctx.q2, ctx.m, ctx.bn_ctx))
107 goto out;
108
109 if (BN_num_bytes(ctx.q2) > SGX_MODULUS_SIZE) {
110 fprintf(stderr, "Too large Q2 %d bytes\n",
111 BN_num_bytes(ctx.q2));
112 goto out;
113 }
114
115 len = BN_bn2bin(ctx.q1, q1);
116 reverse_bytes(q1, len);
117 len = BN_bn2bin(ctx.q2, q2);
118 reverse_bytes(q2, len);
119
120 free_q1q2_ctx(&ctx);
121 return true;
122 out:
123 free_q1q2_ctx(&ctx);
124 return false;
125 }
126
127 struct sgx_sigstruct_payload {
128 struct sgx_sigstruct_header header;
129 struct sgx_sigstruct_body body;
130 };
131
132 static bool check_crypto_errors(void)
133 {
134 int err;
135 bool had_errors = false;
136 const char *filename;
137 int line;
138 char str[256];
139
140 for ( ; ; ) {
141 if (ERR_peek_error() == 0)
142 break;
143
144 had_errors = true;
145 err = ERR_get_error_line(&filename, &line);
146 ERR_error_string_n(err, str, sizeof(str));
147 fprintf(stderr, "crypto: %s: %s:%d\n", str, filename, line);
148 }
149
150 return had_errors;
151 }
152
153 static inline const BIGNUM *get_modulus(RSA *key)
154 {
155 const BIGNUM *n;
156
157 RSA_get0_key(key, &n, NULL, NULL);
158 return n;
159 }
160
161 static RSA *gen_sign_key(void)
162 {
163 unsigned long sign_key_length;
164 BIO *bio;
165 RSA *key;
166
167 sign_key_length = (unsigned long)&sign_key_end -
168 (unsigned long)&sign_key;
169
170 bio = BIO_new_mem_buf(&sign_key, sign_key_length);
171 if (!bio)
172 return NULL;
173
174 key = PEM_read_bio_RSAPrivateKey(bio, NULL, NULL, NULL);
175 BIO_free(bio);
176
177 return key;
178 }
179
180 enum mrtags {
181 MRECREATE = 0x0045544145524345,
182 MREADD = 0x0000000044444145,
183 MREEXTEND = 0x00444E4554584545,
184 };
185
186 static bool mrenclave_update(EVP_MD_CTX *ctx, const void *data)
187 {
188 if (!EVP_DigestUpdate(ctx, data, 64)) {
189 fprintf(stderr, "digest update failed\n");
190 return false;
191 }
192
193 return true;
194 }
195
196 static bool mrenclave_commit(EVP_MD_CTX *ctx, uint8_t *mrenclave)
197 {
198 unsigned int size;
199
200 if (!EVP_DigestFinal_ex(ctx, (unsigned char *)mrenclave, &size)) {
201 fprintf(stderr, "digest commit failed\n");
202 return false;
203 }
204
205 if (size != 32) {
206 fprintf(stderr, "invalid digest size = %u\n", size);
207 return false;
208 }
209
210 return true;
211 }
212
213 struct mrecreate {
214 uint64_t tag;
215 uint32_t ssaframesize;
216 uint64_t size;
217 uint8_t reserved[44];
218 } __attribute__((__packed__));
219
220
221 static bool mrenclave_ecreate(EVP_MD_CTX *ctx, uint64_t blob_size)
222 {
223 struct mrecreate mrecreate;
224 uint64_t encl_size;
225
226 for (encl_size = 0x1000; encl_size < blob_size; )
227 encl_size <<= 1;
228
229 memset(&mrecreate, 0, sizeof(mrecreate));
230 mrecreate.tag = MRECREATE;
231 mrecreate.ssaframesize = 1;
232 mrecreate.size = encl_size;
233
234 if (!EVP_DigestInit_ex(ctx, EVP_sha256(), NULL))
235 return false;
236
237 return mrenclave_update(ctx, &mrecreate);
238 }
239
240 struct mreadd {
241 uint64_t tag;
242 uint64_t offset;
243 uint64_t flags; /* SECINFO flags */
244 uint8_t reserved[40];
245 } __attribute__((__packed__));
246
247 static bool mrenclave_eadd(EVP_MD_CTX *ctx, uint64_t offset, uint64_t flags)
248 {
249 struct mreadd mreadd;
250
251 memset(&mreadd, 0, sizeof(mreadd));
252 mreadd.tag = MREADD;
253 mreadd.offset = offset;
254 mreadd.flags = flags;
255
256 return mrenclave_update(ctx, &mreadd);
257 }
258
259 struct mreextend {
260 uint64_t tag;
261 uint64_t offset;
262 uint8_t reserved[48];
263 } __attribute__((__packed__));
264
265 static bool mrenclave_eextend(EVP_MD_CTX *ctx, uint64_t offset,
266 const uint8_t *data)
267 {
268 struct mreextend mreextend;
269 int i;
270
271 for (i = 0; i < 0x1000; i += 0x100) {
272 memset(&mreextend, 0, sizeof(mreextend));
273 mreextend.tag = MREEXTEND;
274 mreextend.offset = offset + i;
275
276 if (!mrenclave_update(ctx, &mreextend))
277 return false;
278
279 if (!mrenclave_update(ctx, &data[i + 0x00]))
280 return false;
281
282 if (!mrenclave_update(ctx, &data[i + 0x40]))
283 return false;
284
285 if (!mrenclave_update(ctx, &data[i + 0x80]))
286 return false;
287
288 if (!mrenclave_update(ctx, &data[i + 0xC0]))
289 return false;
290 }
291
292 return true;
293 }
294
295 static bool mrenclave_segment(EVP_MD_CTX *ctx, struct encl *encl,
296 struct encl_segment *seg)
297 {
298 uint64_t end = seg->size;
299 uint64_t offset;
300
301 for (offset = 0; offset < end; offset += PAGE_SIZE) {
302 if (!mrenclave_eadd(ctx, seg->offset + offset, seg->flags))
303 return false;
304
305 if (seg->measure) {
306 if (!mrenclave_eextend(ctx, seg->offset + offset, seg->src + offset))
307 return false;
308 }
309 }
310
311 return true;
312 }
313
314 bool encl_measure(struct encl *encl)
315 {
316 uint64_t header1[2] = {0x000000E100000006, 0x0000000000010000};
317 uint64_t header2[2] = {0x0000006000000101, 0x0000000100000060};
318 struct sgx_sigstruct *sigstruct = &encl->sigstruct;
319 struct sgx_sigstruct_payload payload;
320 uint8_t digest[SHA256_DIGEST_LENGTH];
321 EVP_MD_CTX *ctx = NULL;
322 unsigned int siglen;
323 RSA *key = NULL;
324 int i;
325
326 memset(sigstruct, 0, sizeof(*sigstruct));
327
328 sigstruct->header.header1[0] = header1[0];
329 sigstruct->header.header1[1] = header1[1];
330 sigstruct->header.header2[0] = header2[0];
331 sigstruct->header.header2[1] = header2[1];
332 sigstruct->exponent = 3;
333 sigstruct->body.attributes = SGX_ATTR_MODE64BIT;
334 sigstruct->body.xfrm = 3;
335
336 /* sanity check */
337 if (check_crypto_errors())
338 goto err;
339
340 key = gen_sign_key();
341 if (!key) {
342 ERR_print_errors_fp(stdout);
343 goto err;
344 }
345
346 BN_bn2bin(get_modulus(key), sigstruct->modulus);
347
348 ctx = EVP_MD_CTX_create();
349 if (!ctx)
350 goto err;
351
352 if (!mrenclave_ecreate(ctx, encl->src_size))
353 goto err;
354
355 for (i = 0; i < encl->nr_segments; i++) {
356 struct encl_segment *seg = &encl->segment_tbl[i];
357
358 if (!mrenclave_segment(ctx, encl, seg))
359 goto err;
360 }
361
362 if (!mrenclave_commit(ctx, sigstruct->body.mrenclave))
363 goto err;
364
365 memcpy(&payload.header, &sigstruct->header, sizeof(sigstruct->header));
366 memcpy(&payload.body, &sigstruct->body, sizeof(sigstruct->body));
367
368 SHA256((unsigned char *)&payload, sizeof(payload), digest);
369
370 if (!RSA_sign(NID_sha256, digest, SHA256_DIGEST_LENGTH,
371 sigstruct->signature, &siglen, key))
372 goto err;
373
374 if (!calc_q1q2(sigstruct->signature, sigstruct->modulus, sigstruct->q1,
375 sigstruct->q2))
376 goto err;
377
378 /* BE -> LE */
379 reverse_bytes(sigstruct->signature, SGX_MODULUS_SIZE);
380 reverse_bytes(sigstruct->modulus, SGX_MODULUS_SIZE);
381
382 EVP_MD_CTX_destroy(ctx);
383 RSA_free(key);
384 return true;
385
386 err:
387 if (ctx)
388 EVP_MD_CTX_destroy(ctx);
389 RSA_free(key);
390 return false;
391 }
392
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.