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surjectionproof: make sure that n_used_pubkeys > 0 in generate

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If the proof was generated with surjectionproof_initialize (as mandated by the
API docs), then n_used_pubkeys can never be 0. Without this commit, compilers
will (rightfully) warn that borromean_s[ring_input_index] is not initialized in
surjectionproof_generate. Therefore, this commit makes sure that n_used_pubkeys
is greater than 0 which ensures that the array is initialized at
ring_input_index.
This commit is contained in:
Jonas Nick 2022-08-09 20:05:42 +00:00
parent 4fd7e1eabd
commit 5ac8fb035e
2 changed files with 27 additions and 9 deletions
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6
src/modules/surjection/main_impl.h
View File

@ -298,6 +298,10 @@ int secp256k1_surjectionproof_generate(const secp256k1_context* ctx, secp256k1_s
CHECK(proof->initialized == 1);
#endif
n_used_pubkeys = secp256k1_surjectionproof_n_used_inputs(ctx, proof);
/* This must be true if the proof was created with surjectionproof_initialize */
ARG_CHECK(n_used_pubkeys > 0);
/* Compute secret key */
secp256k1_scalar_set_b32(&tmps, input_blinding_key, &overflow);
if (overflow) {
@ -321,7 +325,7 @@ int secp256k1_surjectionproof_generate(const secp256k1_context* ctx, secp256k1_s
/* Compute public keys */
n_total_pubkeys = secp256k1_surjectionproof_n_total_inputs(ctx, proof);
n_used_pubkeys = secp256k1_surjectionproof_n_used_inputs(ctx, proof);
if (n_used_pubkeys > n_total_pubkeys || n_total_pubkeys != n_ephemeral_input_tags) {
return 0;
}

30
src/modules/surjection/tests_impl.h
View File

@ -173,31 +173,45 @@ static void test_surjectionproof_api(void) {
CHECK(secp256k1_surjectionproof_verify(vrfy, &proof, ephemeral_input_tags, n_inputs, NULL) == 0);
CHECK(ecount == 16);
/* Test how surjectionproof_generate fails when the proof was not created
* with surjectionproof_initialize */
ecount = 0;
CHECK(secp256k1_surjectionproof_generate(sign, &proof, ephemeral_input_tags, n_inputs, &ephemeral_output_tag, 0, input_blinding_key[0], output_blinding_key) == 1);
{
secp256k1_surjectionproof tmp_proof = proof;
tmp_proof.n_inputs = 0;
CHECK(secp256k1_surjectionproof_generate(sign, &tmp_proof, ephemeral_input_tags, n_inputs, &ephemeral_output_tag, 0, input_blinding_key[0], output_blinding_key) == 0);
}
CHECK(ecount == 1);
CHECK(secp256k1_surjectionproof_generate(sign, &proof, ephemeral_input_tags, n_inputs, &ephemeral_output_tag, 0, input_blinding_key[0], output_blinding_key) == 1);
/* Check serialize */
ecount = 0;
serialized_len = sizeof(serialized_proof);
CHECK(secp256k1_surjectionproof_serialize(none, serialized_proof, &serialized_len, &proof) != 0);
CHECK(ecount == 16);
CHECK(ecount == 0);
serialized_len = sizeof(serialized_proof);
CHECK(secp256k1_surjectionproof_serialize(none, NULL, &serialized_len, &proof) == 0);
CHECK(ecount == 17);
CHECK(ecount == 1);
serialized_len = sizeof(serialized_proof);
CHECK(secp256k1_surjectionproof_serialize(none, serialized_proof, NULL, &proof) == 0);
CHECK(ecount == 18);
CHECK(ecount == 2);
serialized_len = sizeof(serialized_proof);
CHECK(secp256k1_surjectionproof_serialize(none, serialized_proof, &serialized_len, NULL) == 0);
CHECK(ecount == 19);
CHECK(ecount == 3);
serialized_len = sizeof(serialized_proof);
CHECK(secp256k1_surjectionproof_serialize(none, serialized_proof, &serialized_len, &proof) != 0);
/* Check parse */
CHECK(secp256k1_surjectionproof_parse(none, &proof, serialized_proof, serialized_len) != 0);
CHECK(ecount == 19);
CHECK(ecount == 3);
CHECK(secp256k1_surjectionproof_parse(none, NULL, serialized_proof, serialized_len) == 0);
CHECK(ecount == 20);
CHECK(ecount == 4);
CHECK(secp256k1_surjectionproof_parse(none, &proof, NULL, serialized_len) == 0);
CHECK(ecount == 21);
CHECK(ecount == 5);
CHECK(secp256k1_surjectionproof_parse(none, &proof, serialized_proof, 0) == 0);
CHECK(ecount == 21);
CHECK(ecount == 5);
secp256k1_context_destroy(none);
secp256k1_context_destroy(sign);