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sipasipa
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Make lax_der_privatekey_parsing.h not depend on internal code
1 parent 73f64ff commit 7914a6e

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2 files changed

+23
-53
lines changed

2 files changed

+23
-53
lines changed

‎contrib/lax_der_privatekey_parsing.h‎

Lines changed: 18 additions & 50 deletions
Original file line numberDiff line numberDiff line change
@@ -73,12 +73,11 @@ static SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_import_der(
7373
size_t privkeylen
7474
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
7575

76-
static int secp256k1_eckey_privkey_parse(secp256k1_scalar *key, const unsigned char *privkey, size_t privkeylen) {
77-
unsigned char c[32] = {0};
76+
static int secp256k1_ec_privkey_import_der(const secp256k1_context* ctx, unsigned char *out32, const unsigned char *privkey, size_t privkeylen) {
7877
const unsigned char *end = privkey + privkeylen;
7978
int lenb = 0;
8079
int len = 0;
81-
int overflow = 0;
80+
memset(out32, 0, 32);
8281
/* sequence header */
8382
if (end < privkey+1 || *privkey != 0x30) {
8483
return 0;
@@ -110,18 +109,21 @@ static int secp256k1_eckey_privkey_parse(secp256k1_scalar *key, const unsigned c
110109
if (end < privkey+2 || privkey[0] != 0x04 || privkey[1] > 0x20 || end < privkey+2+privkey[1]) {
111110
return 0;
112111
}
113-
memcpy(c + 32 - privkey[1], privkey + 2, privkey[1]);
114-
secp256k1_scalar_set_b32(key, c, &overflow);
115-
memset(c, 0, 32);
116-
return !overflow;
112+
memcpy(out32 + 32 - privkey[1], privkey + 2, privkey[1]);
113+
if (!secp256k1_ec_seckey_verify(ctx, out32)) {
114+
memset(out32, 0, 32);
115+
return 0;
116+
}
117+
return 1;
117118
}
118119

119-
static int secp256k1_eckey_privkey_serialize(const secp256k1_ecmult_gen_context *ctx, unsigned char *privkey, size_t *privkeylen, const secp256k1_scalar *key, int compressed) {
120-
secp256k1_gej rp;
121-
secp256k1_ge r;
120+
static int secp256k1_ec_privkey_export_der(const secp256k1_context *ctx, unsigned char *privkey, size_t *privkeylen, const unsigned char *key32, int compressed) {
121+
secp256k1_pubkey pubkey;
122122
size_t pubkeylen = 0;
123-
secp256k1_ecmult_gen(ctx, &rp, key);
124-
secp256k1_ge_set_gej(&r, &rp);
123+
if (!secp256k1_ec_pubkey_create(ctx, &pubkey, key32)) {
124+
*privkeylen = 0;
125+
return 0;
126+
}
125127
if (compressed) {
126128
static const unsigned char begin[] = {
127129
0x30,0x81,0xD3,0x02,0x01,0x01,0x04,0x20
@@ -139,11 +141,9 @@ static int secp256k1_eckey_privkey_serialize(const secp256k1_ecmult_gen_context
139141
};
140142
unsigned char *ptr = privkey;
141143
memcpy(ptr, begin, sizeof(begin)); ptr += sizeof(begin);
142-
secp256k1_scalar_get_b32(ptr, key); ptr += 32;
144+
memcpy(ptr, key32, 32); ptr += 32;
143145
memcpy(ptr, middle, sizeof(middle)); ptr += sizeof(middle);
144-
if (!secp256k1_eckey_pubkey_serialize(&r, ptr, &pubkeylen, 1)) {
145-
return 0;
146-
}
146+
secp256k1_ec_pubkey_serialize(ctx, ptr, &pubkeylen, &pubkey, SECP256K1_EC_COMPRESSED);
147147
ptr += pubkeylen;
148148
*privkeylen = ptr - privkey;
149149
} else {
@@ -165,45 +165,13 @@ static int secp256k1_eckey_privkey_serialize(const secp256k1_ecmult_gen_context
165165
};
166166
unsigned char *ptr = privkey;
167167
memcpy(ptr, begin, sizeof(begin)); ptr += sizeof(begin);
168-
secp256k1_scalar_get_b32(ptr, key); ptr += 32;
168+
memcpy(ptr, key32, 32); ptr += 32;
169169
memcpy(ptr, middle, sizeof(middle)); ptr += sizeof(middle);
170-
if (!secp256k1_eckey_pubkey_serialize(&r, ptr, &pubkeylen, 0)) {
171-
return 0;
172-
}
170+
secp256k1_ec_pubkey_serialize(ctx, ptr, &pubkeylen, &pubkey, SECP256K1_EC_UNCOMPRESSED);
173171
ptr += pubkeylen;
174172
*privkeylen = ptr - privkey;
175173
}
176174
return 1;
177175
}
178176

179-
static int secp256k1_ec_privkey_export_der(const secp256k1_context* ctx, unsigned char *privkey, size_t *privkeylen, const unsigned char *seckey, int compressed) {
180-
secp256k1_scalar key;
181-
int ret = 0;
182-
VERIFY_CHECK(ctx != NULL);
183-
ARG_CHECK(seckey != NULL);
184-
ARG_CHECK(privkey != NULL);
185-
ARG_CHECK(privkeylen != NULL);
186-
ARG_CHECK(secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx));
187-
188-
secp256k1_scalar_set_b32(&key, seckey, NULL);
189-
ret = secp256k1_eckey_privkey_serialize(&ctx->ecmult_gen_ctx, privkey, privkeylen, &key, compressed);
190-
secp256k1_scalar_clear(&key);
191-
return ret;
192-
}
193-
194-
static int secp256k1_ec_privkey_import_der(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *privkey, size_t privkeylen) {
195-
secp256k1_scalar key;
196-
int ret = 0;
197-
ARG_CHECK(seckey != NULL);
198-
ARG_CHECK(privkey != NULL);
199-
(void)ctx;
200-
201-
ret = secp256k1_eckey_privkey_parse(&key, privkey, privkeylen);
202-
if (ret) {
203-
secp256k1_scalar_get_b32(seckey, &key);
204-
}
205-
secp256k1_scalar_clear(&key);
206-
return ret;
207-
}
208-
209177
#endif

‎src/tests.c‎

Lines changed: 5 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -3410,13 +3410,13 @@ void run_ecdsa_edge_cases(void) {
34103410
}
34113411

34123412
#ifdef ENABLE_OPENSSL_TESTS
3413-
EC_KEY *get_openssl_key(const secp256k1_scalar *key) {
3413+
EC_KEY *get_openssl_key(const unsigned char *key32) {
34143414
unsigned char privkey[300];
34153415
size_t privkeylen;
34163416
const unsigned char* pbegin = privkey;
34173417
int compr = secp256k1_rand_bits(1);
34183418
EC_KEY *ec_key = EC_KEY_new_by_curve_name(NID_secp256k1);
3419-
CHECK(secp256k1_eckey_privkey_serialize(&ctx->ecmult_gen_ctx, privkey, &privkeylen, key, compr));
3419+
CHECK(secp256k1_ec_privkey_export_der(ctx, privkey, &privkeylen, key32, compr));
34203420
CHECK(d2i_ECPrivateKey(&ec_key, &pbegin, privkeylen));
34213421
CHECK(EC_KEY_check_key(ec_key));
34223422
return ec_key;
@@ -3434,12 +3434,14 @@ void test_ecdsa_openssl(void) {
34343434
size_t secp_sigsize = 80;
34353435
unsigned char message[32];
34363436
unsigned char signature[80];
3437+
unsigned char key32[32];
34373438
secp256k1_rand256_test(message);
34383439
secp256k1_scalar_set_b32(&msg, message, NULL);
34393440
random_scalar_order_test(&key);
3441+
secp256k1_scalar_get_b32(key32, &key);
34403442
secp256k1_ecmult_gen(&ctx->ecmult_gen_ctx, &qj, &key);
34413443
secp256k1_ge_set_gej(&q, &qj);
3442-
ec_key = get_openssl_key(&key);
3444+
ec_key = get_openssl_key(key32);
34433445
CHECK(ec_key != NULL);
34443446
CHECK(ECDSA_sign(0, message, sizeof(message), signature, &sigsize, ec_key));
34453447
CHECK(secp256k1_ecdsa_sig_parse(&sigr, &sigs, signature, sigsize));

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