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Merge pull request #21 from real-or-random/secp256k1-zkp

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Reject surjection proofs with trailing garbage
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Andrew Poelstra 2018-05-23 14:08:15 +00:00 committed by GitHub
commit f1c601ed9d
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2 changed files with 8 additions and 1 deletions
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2
src/modules/surjection/main_impl.h
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@ -56,7 +56,7 @@ int secp256k1_surjectionproof_parse(const secp256k1_context* ctx, secp256k1_surj
}
signature_len = 32 * (1 + secp256k1_count_bits_set(&input[2], (n_inputs + 7) / 8));
if (inputlen < 2 + (n_inputs + 7) / 8 + signature_len) {
if (inputlen != 2 + (n_inputs + 7) / 8 + signature_len) {
return 0;
}
proof->n_inputs = n_inputs;

7
src/modules/surjection/tests_impl.h
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@ -331,6 +331,7 @@ static void test_gen_verify(size_t n_inputs, size_t n_used) {
unsigned char seed[32];
secp256k1_surjectionproof proof;
unsigned char serialized_proof[SECP256K1_SURJECTIONPROOF_SERIALIZATION_BYTES_MAX];
unsigned char serialized_proof_trailing[SECP256K1_SURJECTIONPROOF_SERIALIZATION_BYTES_MAX + 1];
size_t serialized_len = SECP256K1_SURJECTIONPROOF_SERIALIZATION_BYTES_MAX;
secp256k1_fixed_asset_tag fixed_input_tags[1000];
secp256k1_generator ephemeral_input_tags[1000];
@ -376,6 +377,12 @@ static void test_gen_verify(size_t n_inputs, size_t n_used) {
CHECK(secp256k1_surjectionproof_serialize(ctx, serialized_proof, &serialized_len, &proof));
CHECK(serialized_len == secp256k1_surjectionproof_serialized_size(ctx, &proof));
CHECK(serialized_len == SECP256K1_SURJECTIONPROOF_SERIALIZATION_BYTES(n_inputs, n_used));
/* trailing garbage */
memcpy(&serialized_proof_trailing, &serialized_proof, serialized_len);
serialized_proof_trailing[serialized_len] = seed[0];
CHECK(secp256k1_surjectionproof_parse(ctx, &proof, serialized_proof, serialized_len + 1) == 0);
CHECK(secp256k1_surjectionproof_parse(ctx, &proof, serialized_proof, serialized_len));
result = secp256k1_surjectionproof_verify(ctx, &proof, ephemeral_input_tags, n_inputs, &ephemeral_input_tags[n_inputs]);
CHECK(result == 1);