summaryrefslogtreecommitdiff
path: root/tools/testing/selftests/sgx/sigstruct.c
blob: dee7a3d6c5a5f8d8505b174dfdcdbf4e4fe2c4df (plain)
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
// SPDX-License-Identifier: GPL-2.0
/*  Copyright(c) 2016-20 Intel Corporation. */

#define _GNU_SOURCE
#include <assert.h>
#include <getopt.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <openssl/err.h>
#include <openssl/pem.h>
#include "defines.h"
#include "main.h"

struct q1q2_ctx {
	BN_CTX *bn_ctx;
	BIGNUM *m;
	BIGNUM *s;
	BIGNUM *q1;
	BIGNUM *qr;
	BIGNUM *q2;
};

static void free_q1q2_ctx(struct q1q2_ctx *ctx)
{
	BN_CTX_free(ctx->bn_ctx);
	BN_free(ctx->m);
	BN_free(ctx->s);
	BN_free(ctx->q1);
	BN_free(ctx->qr);
	BN_free(ctx->q2);
}

static bool alloc_q1q2_ctx(const uint8_t *s, const uint8_t *m,
			   struct q1q2_ctx *ctx)
{
	ctx->bn_ctx = BN_CTX_new();
	ctx->s = BN_bin2bn(s, SGX_MODULUS_SIZE, NULL);
	ctx->m = BN_bin2bn(m, SGX_MODULUS_SIZE, NULL);
	ctx->q1 = BN_new();
	ctx->qr = BN_new();
	ctx->q2 = BN_new();

	if (!ctx->bn_ctx || !ctx->s || !ctx->m || !ctx->q1 || !ctx->qr ||
	    !ctx->q2) {
		free_q1q2_ctx(ctx);
		return false;
	}

	return true;
}

static bool calc_q1q2(const uint8_t *s, const uint8_t *m, uint8_t *q1,
		      uint8_t *q2)
{
	struct q1q2_ctx ctx;

	if (!alloc_q1q2_ctx(s, m, &ctx)) {
		fprintf(stderr, "Not enough memory for Q1Q2 calculation\n");
		return false;
	}

	if (!BN_mul(ctx.q1, ctx.s, ctx.s, ctx.bn_ctx))
		goto out;

	if (!BN_div(ctx.q1, ctx.qr, ctx.q1, ctx.m, ctx.bn_ctx))
		goto out;

	if (BN_num_bytes(ctx.q1) > SGX_MODULUS_SIZE) {
		fprintf(stderr, "Too large Q1 %d bytes\n",
			BN_num_bytes(ctx.q1));
		goto out;
	}

	if (!BN_mul(ctx.q2, ctx.s, ctx.qr, ctx.bn_ctx))
		goto out;

	if (!BN_div(ctx.q2, NULL, ctx.q2, ctx.m, ctx.bn_ctx))
		goto out;

	if (BN_num_bytes(ctx.q2) > SGX_MODULUS_SIZE) {
		fprintf(stderr, "Too large Q2 %d bytes\n",
			BN_num_bytes(ctx.q2));
		goto out;
	}

	BN_bn2bin(ctx.q1, q1);
	BN_bn2bin(ctx.q2, q2);

	free_q1q2_ctx(&ctx);
	return true;
out:
	free_q1q2_ctx(&ctx);
	return false;
}

struct sgx_sigstruct_payload {
	struct sgx_sigstruct_header header;
	struct sgx_sigstruct_body body;
};

static bool check_crypto_errors(void)
{
	int err;
	bool had_errors = false;
	const char *filename;
	int line;
	char str[256];

	for ( ; ; ) {
		if (ERR_peek_error() == 0)
			break;

		had_errors = true;
		err = ERR_get_error_line(&filename, &line);
		ERR_error_string_n(err, str, sizeof(str));
		fprintf(stderr, "crypto: %s: %s:%d\n", str, filename, line);
	}

	return had_errors;
}

static inline const BIGNUM *get_modulus(RSA *key)
{
	const BIGNUM *n;

	RSA_get0_key(key, &n, NULL, NULL);
	return n;
}

static RSA *gen_sign_key(void)
{
	unsigned long sign_key_length;
	BIO *bio;
	RSA *key;

	sign_key_length = (unsigned long)&sign_key_end -
			  (unsigned long)&sign_key;

	bio = BIO_new_mem_buf(&sign_key, sign_key_length);
	if (!bio)
		return NULL;

	key = PEM_read_bio_RSAPrivateKey(bio, NULL, NULL, NULL);
	BIO_free(bio);

	return key;
}

static void reverse_bytes(void *data, int length)
{
	int i = 0;
	int j = length - 1;
	uint8_t temp;
	uint8_t *ptr = data;

	while (i < j) {
		temp = ptr[i];
		ptr[i] = ptr[j];
		ptr[j] = temp;
		i++;
		j--;
	}
}

enum mrtags {
	MRECREATE = 0x0045544145524345,
	MREADD = 0x0000000044444145,
	MREEXTEND = 0x00444E4554584545,
};

static bool mrenclave_update(EVP_MD_CTX *ctx, const void *data)
{
	if (!EVP_DigestUpdate(ctx, data, 64)) {
		fprintf(stderr, "digest update failed\n");
		return false;
	}

	return true;
}

static bool mrenclave_commit(EVP_MD_CTX *ctx, uint8_t *mrenclave)
{
	unsigned int size;

	if (!EVP_DigestFinal_ex(ctx, (unsigned char *)mrenclave, &size)) {
		fprintf(stderr, "digest commit failed\n");
		return false;
	}

	if (size != 32) {
		fprintf(stderr, "invalid digest size = %u\n", size);
		return false;
	}

	return true;
}

struct mrecreate {
	uint64_t tag;
	uint32_t ssaframesize;
	uint64_t size;
	uint8_t reserved[44];
} __attribute__((__packed__));


static bool mrenclave_ecreate(EVP_MD_CTX *ctx, uint64_t blob_size)
{
	struct mrecreate mrecreate;
	uint64_t encl_size;

	for (encl_size = 0x1000; encl_size < blob_size; )
		encl_size <<= 1;

	memset(&mrecreate, 0, sizeof(mrecreate));
	mrecreate.tag = MRECREATE;
	mrecreate.ssaframesize = 1;
	mrecreate.size = encl_size;

	if (!EVP_DigestInit_ex(ctx, EVP_sha256(), NULL))
		return false;

	return mrenclave_update(ctx, &mrecreate);
}

struct mreadd {
	uint64_t tag;
	uint64_t offset;
	uint64_t flags; /* SECINFO flags */
	uint8_t reserved[40];
} __attribute__((__packed__));

static bool mrenclave_eadd(EVP_MD_CTX *ctx, uint64_t offset, uint64_t flags)
{
	struct mreadd mreadd;

	memset(&mreadd, 0, sizeof(mreadd));
	mreadd.tag = MREADD;
	mreadd.offset = offset;
	mreadd.flags = flags;

	return mrenclave_update(ctx, &mreadd);
}

struct mreextend {
	uint64_t tag;
	uint64_t offset;
	uint8_t reserved[48];
} __attribute__((__packed__));

static bool mrenclave_eextend(EVP_MD_CTX *ctx, uint64_t offset,
			      const uint8_t *data)
{
	struct mreextend mreextend;
	int i;

	for (i = 0; i < 0x1000; i += 0x100) {
		memset(&mreextend, 0, sizeof(mreextend));
		mreextend.tag = MREEXTEND;
		mreextend.offset = offset + i;

		if (!mrenclave_update(ctx, &mreextend))
			return false;

		if (!mrenclave_update(ctx, &data[i + 0x00]))
			return false;

		if (!mrenclave_update(ctx, &data[i + 0x40]))
			return false;

		if (!mrenclave_update(ctx, &data[i + 0x80]))
			return false;

		if (!mrenclave_update(ctx, &data[i + 0xC0]))
			return false;
	}

	return true;
}

static bool mrenclave_segment(EVP_MD_CTX *ctx, struct encl *encl,
			      struct encl_segment *seg)
{
	uint64_t end = seg->offset + seg->size;
	uint64_t offset;

	for (offset = seg->offset; offset < end; offset += PAGE_SIZE) {
		if (!mrenclave_eadd(ctx, offset, seg->flags))
			return false;

		if (!mrenclave_eextend(ctx, offset, encl->src + offset))
			return false;
	}

	return true;
}

bool encl_measure(struct encl *encl)
{
	uint64_t header1[2] = {0x000000E100000006, 0x0000000000010000};
	uint64_t header2[2] = {0x0000006000000101, 0x0000000100000060};
	struct sgx_sigstruct *sigstruct = &encl->sigstruct;
	struct sgx_sigstruct_payload payload;
	uint8_t digest[SHA256_DIGEST_LENGTH];
	unsigned int siglen;
	RSA *key = NULL;
	EVP_MD_CTX *ctx;
	int i;

	memset(sigstruct, 0, sizeof(*sigstruct));

	sigstruct->header.header1[0] = header1[0];
	sigstruct->header.header1[1] = header1[1];
	sigstruct->header.header2[0] = header2[0];
	sigstruct->header.header2[1] = header2[1];
	sigstruct->exponent = 3;
	sigstruct->body.attributes = SGX_ATTR_MODE64BIT;
	sigstruct->body.xfrm = 3;

	/* sanity check */
	if (check_crypto_errors())
		goto err;

	key = gen_sign_key();
	if (!key) {
		ERR_print_errors_fp(stdout);
		goto err;
	}

	BN_bn2bin(get_modulus(key), sigstruct->modulus);

	ctx = EVP_MD_CTX_create();
	if (!ctx)
		goto err;

	if (!mrenclave_ecreate(ctx, encl->src_size))
		goto err;

	for (i = 0; i < encl->nr_segments; i++) {
		struct encl_segment *seg = &encl->segment_tbl[i];

		if (!mrenclave_segment(ctx, encl, seg))
			goto err;
	}

	if (!mrenclave_commit(ctx, sigstruct->body.mrenclave))
		goto err;

	memcpy(&payload.header, &sigstruct->header, sizeof(sigstruct->header));
	memcpy(&payload.body, &sigstruct->body, sizeof(sigstruct->body));

	SHA256((unsigned char *)&payload, sizeof(payload), digest);

	if (!RSA_sign(NID_sha256, digest, SHA256_DIGEST_LENGTH,
		      sigstruct->signature, &siglen, key))
		goto err;

	if (!calc_q1q2(sigstruct->signature, sigstruct->modulus, sigstruct->q1,
		       sigstruct->q2))
		goto err;

	/* BE -> LE */
	reverse_bytes(sigstruct->signature, SGX_MODULUS_SIZE);
	reverse_bytes(sigstruct->modulus, SGX_MODULUS_SIZE);
	reverse_bytes(sigstruct->q1, SGX_MODULUS_SIZE);
	reverse_bytes(sigstruct->q2, SGX_MODULUS_SIZE);

	EVP_MD_CTX_destroy(ctx);
	RSA_free(key);
	return true;

err:
	EVP_MD_CTX_destroy(ctx);
	RSA_free(key);
	return false;
}