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Merge pull request bitcoin#339
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9234391 Overhaul flags handling (Pieter Wuille)
1a36898 Make flags more explicit, add runtime checks. (Rusty Russell)
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@sipa
sipa committed Oct 25, 2015
2 parents 1a3e03a + 9234391 commit 73f64ff
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Showing 6 changed files with 44 additions and 28 deletions.
16 changes: 8 additions & 8 deletions contrib/lax_der_privatekey_parsing.h
View file
Expand Up @@ -34,22 +34,22 @@
* privkeylen: Pointer to an int where the length of the private key in
* privkey will be stored.
* In: seckey: pointer to a 32-byte secret key to export.
* flags: SECP256K1_EC_COMPRESSED if the key should be exported in
* compressed format.
* compressed: 1 if the key should be exported in
* compressed format, 0 otherwise
*
* This function is purely meant for compatibility with applications that
* require BER encoded keys. When working with secp256k1-specific code, the
* simple 32-byte private keys are sufficient.
*
* Note that this function does not guarantee correct DER output. It is
* guaranteed to be parsable by secp256k1_ec_privkey_import.
* guaranteed to be parsable by secp256k1_ec_privkey_import_der
*/
static SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_export_der(
const secp256k1_context* ctx,
unsigned char *privkey,
size_t *privkeylen,
const unsigned char *seckey,
unsigned int flags
int compressed
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);

/** Import a private key in DER format.
Expand Down Expand Up @@ -116,13 +116,13 @@ static int secp256k1_eckey_privkey_parse(secp256k1_scalar *key, const unsigned c
return !overflow;
}

static int secp256k1_eckey_privkey_serialize(const secp256k1_ecmult_gen_context *ctx, unsigned char *privkey, size_t *privkeylen, const secp256k1_scalar *key, unsigned int flags) {
static int secp256k1_eckey_privkey_serialize(const secp256k1_ecmult_gen_context *ctx, unsigned char *privkey, size_t *privkeylen, const secp256k1_scalar *key, int compressed) {
secp256k1_gej rp;
secp256k1_ge r;
size_t pubkeylen = 0;
secp256k1_ecmult_gen(ctx, &rp, key);
secp256k1_ge_set_gej(&r, &rp);
if (flags & SECP256K1_EC_COMPRESSED) {
if (compressed) {
static const unsigned char begin[] = {
0x30,0x81,0xD3,0x02,0x01,0x01,0x04,0x20
};
Expand Down Expand Up @@ -176,7 +176,7 @@ static int secp256k1_eckey_privkey_serialize(const secp256k1_ecmult_gen_context
return 1;
}

static int secp256k1_ec_privkey_export_der(const secp256k1_context* ctx, unsigned char *privkey, size_t *privkeylen, const unsigned char *seckey, unsigned int flags) {
static int secp256k1_ec_privkey_export_der(const secp256k1_context* ctx, unsigned char *privkey, size_t *privkeylen, const unsigned char *seckey, int compressed) {
secp256k1_scalar key;
int ret = 0;
VERIFY_CHECK(ctx != NULL);
Expand All @@ -186,7 +186,7 @@ static int secp256k1_ec_privkey_export_der(const secp256k1_context* ctx, unsigne
ARG_CHECK(secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx));

secp256k1_scalar_set_b32(&key, seckey, NULL);
ret = secp256k1_eckey_privkey_serialize(&ctx->ecmult_gen_ctx, privkey, privkeylen, &key, flags);
ret = secp256k1_eckey_privkey_serialize(&ctx->ecmult_gen_ctx, privkey, privkeylen, &key, compressed);
secp256k1_scalar_clear(&key);
return ret;
}
Expand Down
19 changes: 15 additions & 4 deletions include/secp256k1.h
View file
Expand Up @@ -147,12 +147,23 @@ typedef int (*secp256k1_nonce_function)(
# define SECP256K1_ARG_NONNULL(_x)
# endif

/** All flags' lower 8 bits indicate what they're for. Do not use directly. */
#define SECP256K1_FLAGS_TYPE_MASK ((1 << 8) - 1)
#define SECP256K1_FLAGS_TYPE_CONTEXT (1 << 0)
#define SECP256K1_FLAGS_TYPE_COMPRESSION (1 << 1)
/** The higher bits contain the actual data. Do not use directly. */
#define SECP256K1_FLAGS_BIT_CONTEXT_VERIFY (1 << 8)
#define SECP256K1_FLAGS_BIT_CONTEXT_SIGN (1 << 9)
#define SECP256K1_FLAGS_BIT_COMPRESSION (1 << 8)

/** Flags to pass to secp256k1_context_create. */
# define SECP256K1_CONTEXT_VERIFY (1 << 0)
# define SECP256K1_CONTEXT_SIGN (1 << 1)
#define SECP256K1_CONTEXT_VERIFY (SECP256K1_FLAGS_TYPE_CONTEXT | SECP256K1_FLAGS_BIT_CONTEXT_VERIFY)
#define SECP256K1_CONTEXT_SIGN (SECP256K1_FLAGS_TYPE_CONTEXT | SECP256K1_FLAGS_BIT_CONTEXT_SIGN)
#define SECP256K1_CONTEXT_NONE (SECP256K1_FLAGS_TYPE_CONTEXT)

/** Flag to pass to secp256k1_ec_pubkey_serialize and secp256k1_ec_privkey_export. */
# define SECP256K1_EC_COMPRESSED (1 << 0)
#define SECP256K1_EC_COMPRESSED (SECP256K1_FLAGS_TYPE_COMPRESSION | SECP256K1_FLAGS_BIT_COMPRESSION)
#define SECP256K1_EC_UNCOMPRESSED (SECP256K1_FLAGS_TYPE_COMPRESSION)

/** Create a secp256k1 context object.
*
Expand Down Expand Up @@ -261,7 +272,7 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_parse(
* In: pubkey: a pointer to a secp256k1_pubkey containing an initialized
* public key.
* flags: SECP256K1_EC_COMPRESSED if serialization should be in
* compressed format.
* compressed format, otherwise SECP256K1_EC_UNCOMPRESSED.
*/
SECP256K1_API int secp256k1_ec_pubkey_serialize(
const secp256k1_context* ctx,
Expand Down
5 changes: 1 addition & 4 deletions src/eckey.h
View file
Expand Up @@ -15,10 +15,7 @@
#include "ecmult_gen.h"

static int secp256k1_eckey_pubkey_parse(secp256k1_ge *elem, const unsigned char *pub, size_t size);
static int secp256k1_eckey_pubkey_serialize(secp256k1_ge *elem, unsigned char *pub, size_t *size, unsigned int flags);

static int secp256k1_eckey_privkey_parse(secp256k1_scalar *key, const unsigned char *privkey, size_t privkeylen);
static int secp256k1_eckey_privkey_serialize(const secp256k1_ecmult_gen_context *ctx, unsigned char *privkey, size_t *privkeylen, const secp256k1_scalar *key, unsigned int flags);
static int secp256k1_eckey_pubkey_serialize(secp256k1_ge *elem, unsigned char *pub, size_t *size, int compressed);

static int secp256k1_eckey_privkey_tweak_add(secp256k1_scalar *key, const secp256k1_scalar *tweak);
static int secp256k1_eckey_pubkey_tweak_add(const secp256k1_ecmult_context *ctx, secp256k1_ge *key, const secp256k1_scalar *tweak);
Expand Down
4 changes: 2 additions & 2 deletions src/eckey_impl.h
View file
Expand Up @@ -33,14 +33,14 @@ static int secp256k1_eckey_pubkey_parse(secp256k1_ge *elem, const unsigned char
}
}

static int secp256k1_eckey_pubkey_serialize(secp256k1_ge *elem, unsigned char *pub, size_t *size, unsigned int flags) {
static int secp256k1_eckey_pubkey_serialize(secp256k1_ge *elem, unsigned char *pub, size_t *size, int compressed) {
if (secp256k1_ge_is_infinity(elem)) {
return 0;
}
secp256k1_fe_normalize_var(&elem->x);
secp256k1_fe_normalize_var(&elem->y);
secp256k1_fe_get_b32(&pub[1], &elem->x);
if (flags & SECP256K1_EC_COMPRESSED) {
if (compressed) {
*size = 33;
pub[0] = 0x02 | (secp256k1_fe_is_odd(&elem->y) ? 0x01 : 0x00);
} else {
Expand Down
14 changes: 11 additions & 3 deletions src/secp256k1.c
View file
Expand Up @@ -62,13 +62,20 @@ secp256k1_context* secp256k1_context_create(unsigned int flags) {
ret->illegal_callback = default_illegal_callback;
ret->error_callback = default_error_callback;

if (EXPECT((flags & SECP256K1_FLAGS_TYPE_MASK) != SECP256K1_FLAGS_TYPE_CONTEXT, 0)) {
secp256k1_callback_call(&ret->illegal_callback,
"Invalid flags");
free(ret);
return NULL;
}

secp256k1_ecmult_context_init(&ret->ecmult_ctx);
secp256k1_ecmult_gen_context_init(&ret->ecmult_gen_ctx);

if (flags & SECP256K1_CONTEXT_SIGN) {
if (flags & SECP256K1_FLAGS_BIT_CONTEXT_SIGN) {
secp256k1_ecmult_gen_context_build(&ret->ecmult_gen_ctx, &ret->error_callback);
}
if (flags & SECP256K1_CONTEXT_VERIFY) {
if (flags & SECP256K1_FLAGS_BIT_CONTEXT_VERIFY) {
secp256k1_ecmult_context_build(&ret->ecmult_ctx, &ret->error_callback);
}

Expand Down Expand Up @@ -166,8 +173,9 @@ int secp256k1_ec_pubkey_serialize(const secp256k1_context* ctx, unsigned char *o
ARG_CHECK(output != NULL);
ARG_CHECK(outputlen != NULL);
ARG_CHECK(pubkey != NULL);
ARG_CHECK((flags & SECP256K1_FLAGS_TYPE_MASK) == SECP256K1_FLAGS_TYPE_COMPRESSION);
return (secp256k1_pubkey_load(ctx, &Q, pubkey) &&
secp256k1_eckey_pubkey_serialize(&Q, output, outputlen, flags));
secp256k1_eckey_pubkey_serialize(&Q, output, outputlen, flags & SECP256K1_FLAGS_BIT_COMPRESSION));
}

static void secp256k1_ecdsa_signature_load(const secp256k1_context* ctx, secp256k1_scalar* r, secp256k1_scalar* s, const secp256k1_ecdsa_signature* sig) {
Expand Down
14 changes: 7 additions & 7 deletions src/tests.c
View file
Expand Up @@ -139,7 +139,7 @@ void run_context_tests(void) {
unsigned char ctmp[32];
int32_t ecount;
int32_t ecount2;
secp256k1_context *none = secp256k1_context_create(0);
secp256k1_context *none = secp256k1_context_create(SECP256K1_CONTEXT_NONE);
secp256k1_context *sign = secp256k1_context_create(SECP256K1_CONTEXT_SIGN);
secp256k1_context *vrfy = secp256k1_context_create(SECP256K1_CONTEXT_VERIFY);
secp256k1_context *both = secp256k1_context_create(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY);
Expand Down Expand Up @@ -1964,7 +1964,7 @@ void ec_pubkey_parse_pointtest(const unsigned char *input, int xvalid, int yvali
VG_CHECK(&pubkey, sizeof(pubkey));
outl = 65;
VG_UNDEF(pubkeyo, 65);
CHECK(secp256k1_ec_pubkey_serialize(ctx, pubkeyo, &outl, &pubkey, 0) == 1);
CHECK(secp256k1_ec_pubkey_serialize(ctx, pubkeyo, &outl, &pubkey, SECP256K1_EC_UNCOMPRESSED) == 1);
VG_CHECK(pubkeyo, outl);
CHECK(outl == 65);
CHECK(pubkeyo[0] == 4);
Expand Down Expand Up @@ -2575,12 +2575,12 @@ void test_ecdsa_end_to_end(void) {
CHECK(secp256k1_ec_pubkey_create(ctx, &pubkey, privkey) == 1);

/* Verify exporting and importing public key. */
CHECK(secp256k1_ec_pubkey_serialize(ctx, pubkeyc, &pubkeyclen, &pubkey, secp256k1_rand_bits(1)) == 1);
CHECK(secp256k1_ec_pubkey_serialize(ctx, pubkeyc, &pubkeyclen, &pubkey, secp256k1_rand_bits(1) == 1 ? SECP256K1_EC_COMPRESSED : SECP256K1_EC_UNCOMPRESSED));
memset(&pubkey, 0, sizeof(pubkey));
CHECK(secp256k1_ec_pubkey_parse(ctx, &pubkey, pubkeyc, pubkeyclen) == 1);

/* Verify private key import and export. */
CHECK(secp256k1_ec_privkey_export_der(ctx, seckey, &seckeylen, privkey, secp256k1_rand_bits(1) == 1) ? SECP256K1_EC_COMPRESSED : 0);
CHECK(secp256k1_ec_privkey_export_der(ctx, seckey, &seckeylen, privkey, secp256k1_rand_bits(1) == 1));
CHECK(secp256k1_ec_privkey_import_der(ctx, privkey2, seckey, seckeylen) == 1);
CHECK(memcmp(privkey, privkey2, 32) == 0);

Expand Down Expand Up @@ -2698,7 +2698,7 @@ void test_random_pubkeys(void) {
size_t size = len;
firstb = in[0];
/* If the pubkey can be parsed, it should round-trip... */
CHECK(secp256k1_eckey_pubkey_serialize(&elem, out, &size, (len == 33) ? SECP256K1_EC_COMPRESSED : 0));
CHECK(secp256k1_eckey_pubkey_serialize(&elem, out, &size, len == 33));
CHECK(size == len);
CHECK(memcmp(&in[1], &out[1], len-1) == 0);
/* ... except for the type of hybrid inputs. */
Expand Down Expand Up @@ -3401,7 +3401,7 @@ void test_ecdsa_edge_cases(void) {
size_t outlen = 300;
CHECK(!secp256k1_ec_privkey_export_der(ctx, privkey, &outlen, seckey, 0));
outlen = 300;
CHECK(!secp256k1_ec_privkey_export_der(ctx, privkey, &outlen, seckey, SECP256K1_EC_COMPRESSED));
CHECK(!secp256k1_ec_privkey_export_der(ctx, privkey, &outlen, seckey, 1));
}
}

Expand All @@ -3416,7 +3416,7 @@ EC_KEY *get_openssl_key(const secp256k1_scalar *key) {
const unsigned char* pbegin = privkey;
int compr = secp256k1_rand_bits(1);
EC_KEY *ec_key = EC_KEY_new_by_curve_name(NID_secp256k1);
CHECK(secp256k1_eckey_privkey_serialize(&ctx->ecmult_gen_ctx, privkey, &privkeylen, key, compr ? SECP256K1_EC_COMPRESSED : 0));
CHECK(secp256k1_eckey_privkey_serialize(&ctx->ecmult_gen_ctx, privkey, &privkeylen, key, compr));
CHECK(d2i_ECPrivateKey(&ec_key, &pbegin, privkeylen));
CHECK(EC_KEY_check_key(ec_key));
return ec_key;
Expand Down

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