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whitelist: fix serialize/parse API to take serialized length

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Andrew Poelstra 2017-06-26 17:08:47 +00:00 committed by Tim Ruffing
parent 660ad39fb3
commit 29d0d562dc
3 changed files with 26 additions and 10 deletions
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7
include/secp256k1_whitelist.h
View File

@ -43,6 +43,7 @@ typedef struct {
* Args: ctx: a secp256k1 context object
* Out: sig: a pointer to a signature object
* In: input: a pointer to the array to parse
* input_len: the length of the above array
*
* The signature must consist of a 1-byte n_keys value, followed by a 32-byte
* big endian e0 value, followed by n_keys many 32-byte big endian s values.
@ -50,6 +51,7 @@ typedef struct {
* is invalid.
*
* The total length of the input array must therefore be 33 + 32 * n_keys.
* If the length `input_len` does not match this value, parsing will fail.
*
* After the call, sig will always be initialized. If parsing failed or any
* scalar values overflow or are zero, the resulting sig value is guaranteed
@ -58,7 +60,8 @@ typedef struct {
SECP256K1_API int secp256k1_whitelist_signature_parse(
const secp256k1_context* ctx,
secp256k1_whitelist_signature *sig,
const unsigned char *input
const unsigned char *input,
size_t input_len
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Returns the number of keys a signature expects to have.
@ -75,6 +78,7 @@ SECP256K1_API size_t secp256k1_whitelist_signature_n_keys(
* Returns: 1
* Args: ctx: a secp256k1 context object
* Out: output64: a pointer to an array to store the serialization
* In/Out: output_len: length of the above array, updated with the actual serialized length
* In: sig: a pointer to an initialized signature object
*
* See secp256k1_whitelist_signature_parse for details about the encoding.
@ -82,6 +86,7 @@ SECP256K1_API size_t secp256k1_whitelist_signature_n_keys(
SECP256K1_API int secp256k1_whitelist_signature_serialize(
const secp256k1_context* ctx,
unsigned char *output,
size_t *output_len,
const secp256k1_whitelist_signature *sig
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);

11
src/modules/whitelist/main_impl.h
View File

@ -136,13 +136,13 @@ size_t secp256k1_whitelist_signature_n_keys(const secp256k1_whitelist_signature
return sig->n_keys;
}
int secp256k1_whitelist_signature_parse(const secp256k1_context* ctx, secp256k1_whitelist_signature *sig, const unsigned char *input) {
int secp256k1_whitelist_signature_parse(const secp256k1_context* ctx, secp256k1_whitelist_signature *sig, const unsigned char *input, size_t input_len) {
VERIFY_CHECK(ctx != NULL);
ARG_CHECK(sig != NULL);
ARG_CHECK(input != NULL);
sig->n_keys = input[0];
if (sig->n_keys >= MAX_KEYS) {
if (sig->n_keys >= MAX_KEYS || input_len != 1 + 32 * (sig->n_keys + 1)) {
return 0;
}
memcpy(&sig->data[0], &input[1], 32 * (sig->n_keys + 1));
@ -150,13 +150,18 @@ int secp256k1_whitelist_signature_parse(const secp256k1_context* ctx, secp256k1_
return 1;
}
int secp256k1_whitelist_signature_serialize(const secp256k1_context* ctx, unsigned char *output, const secp256k1_whitelist_signature *sig) {
int secp256k1_whitelist_signature_serialize(const secp256k1_context* ctx, unsigned char *output, size_t *output_len, const secp256k1_whitelist_signature *sig) {
VERIFY_CHECK(ctx != NULL);
ARG_CHECK(output != NULL);
ARG_CHECK(sig != NULL);
if (*output_len < 1 + 32 * (sig->n_keys + 1)) {
return 0;
}
output[0] = sig->n_keys;
memcpy(&output[1], &sig->data[0], 32 * (sig->n_keys + 1));
*output_len = 1 + 32 * (sig->n_keys + 1);
return 1;
}

12
src/modules/whitelist/tests_impl.h
View File

@ -53,6 +53,7 @@ void test_whitelist_end_to_end(const size_t n_keys) {
/* Sign/verify with each one */
for (i = 0; i < n_keys; i++) {
unsigned char serialized[32 + 4 + 32 * SECP256K1_WHITELIST_MAX_N_KEYS] = {0};
size_t slen = sizeof(serialized);
secp256k1_whitelist_signature sig;
secp256k1_whitelist_signature sig1;
@ -61,8 +62,13 @@ void test_whitelist_end_to_end(const size_t n_keys) {
/* Check that exchanging keys causes a failure */
CHECK(secp256k1_whitelist_verify(ctx, &sig, offline_pubkeys, online_pubkeys, &sub_pubkey) != 1);
/* Serialization round trip */
CHECK(secp256k1_whitelist_signature_serialize(ctx, serialized, &sig) == 1);
CHECK(secp256k1_whitelist_signature_parse(ctx, &sig1, serialized) == 1);
CHECK(secp256k1_whitelist_signature_serialize(ctx, serialized, &slen, &sig) == 1);
CHECK(secp256k1_whitelist_signature_parse(ctx, &sig1, serialized, slen) == 1);
/* (Check various bad-length conditions) */
CHECK(secp256k1_whitelist_signature_parse(ctx, &sig1, serialized, slen + 32) == 0);
CHECK(secp256k1_whitelist_signature_parse(ctx, &sig1, serialized, slen + 1) == 0);
CHECK(secp256k1_whitelist_signature_parse(ctx, &sig1, serialized, slen - 1) == 0);
CHECK(secp256k1_whitelist_signature_parse(ctx, &sig1, serialized, 0) == 0);
CHECK(secp256k1_whitelist_verify(ctx, &sig1, online_pubkeys, offline_pubkeys, &sub_pubkey) == 1);
CHECK(secp256k1_whitelist_verify(ctx, &sig1, offline_pubkeys, online_pubkeys, &sub_pubkey) != 1);
/* Test n_keys */
@ -93,7 +99,7 @@ void test_whitelist_bad_parse(void) {
};
secp256k1_whitelist_signature sig;
CHECK(secp256k1_whitelist_signature_parse(ctx, &sig, serialized) == 0);
CHECK(secp256k1_whitelist_signature_parse(ctx, &sig, serialized, sizeof(serialized)) == 0);
}
void run_whitelist_tests(void) {