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add checks #248

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Merged
arvidn merged 2 commits into from
May 21, 2025
Merged

add checks #248

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f67f457
add checks
almogdepaz May 13, 2025
8d81ad0
remove redundant check
almogdepaz May 21, 2025
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23 changes: 18 additions & 5 deletions src/verifier.h
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Original file line number Diff line number Diff line change
Expand Up @@ -45,13 +45,17 @@ bool CheckProofOfTimeNWesolowski(integer D, const uint8_t* x_s, const uint8_t* p
{
int form_size = BQFC_FORM_SIZE;
int segment_len = 8 + B_bytes + form_size;
// Enforce all invariants and bounds before the loop
if (form_size <= 0) return false;
if (depth < 0 || proof_blob_len != 2 * form_size + depth * segment_len)
return false;
if (x_s == nullptr || proof_blob == nullptr)
return false;

// All accesses in the loop are now safe
int i = proof_blob_len - segment_len;
form x = DeserializeForm(D, x_s, form_size);

if (proof_blob_len != 2 * form_size + depth * segment_len)
return false;

// Loop depth times
bool is_valid = false;
for (; i >= 2 * form_size; i -= segment_len) {
uint64_t segment_iters = BytesToInt64(&proof_blob[i]);
Expand All @@ -68,6 +72,7 @@ bool CheckProofOfTimeNWesolowski(integer D, const uint8_t* x_s, const uint8_t* p
iterations -= segment_iters;
}

// Final forms are guaranteed to be in-bounds
VerifyWesolowskiProof(D, x,
DeserializeForm(D, proof_blob, form_size),
DeserializeForm(D, &proof_blob[form_size], form_size),
Expand All @@ -79,6 +84,11 @@ bool CheckProofOfTimeNWesolowski(integer D, const uint8_t* x_s, const uint8_t* p
bool CheckProofOfTimeNWesolowskiCommon(integer& D, form& x, const uint8_t* proof_blob, int32_t proof_blob_len, uint64_t& iterations, int last_segment, bool skip_check = false) {
int form_size = BQFC_FORM_SIZE;
int segment_len = 8 + B_bytes + form_size;
if (proof_blob == nullptr) return false;
if (last_segment < 0 || proof_blob_len < 0) return false;
if (proof_blob_len < last_segment) return false;
if ((proof_blob_len - last_segment) % segment_len != 0)
return false;
int i = proof_blob_len - segment_len;
PulmarkReducer reducer;

Expand Down Expand Up @@ -110,6 +120,7 @@ bool CheckProofOfTimeNWesolowskiCommon(integer& D, form& x, const uint8_t* proof
std::pair<bool, std::vector<uint8_t>> CheckProofOfTimeNWesolowskiWithB(integer D, integer B, const uint8_t* x_s, const uint8_t* proof_blob, int32_t proof_blob_len, uint64_t iterations, int32_t depth) {
int form_size = BQFC_FORM_SIZE;
int segment_len = 8 + B_bytes + form_size;
if (x_s == nullptr || proof_blob == nullptr) return {false, {}};
form x = DeserializeForm(D, x_s, form_size);
std::vector<uint8_t> result;
if (proof_blob_len != form_size + depth * segment_len) {
Expand All @@ -119,6 +130,7 @@ std::pair<bool, std::vector<uint8_t>> CheckProofOfTimeNWesolowskiWithB(integer D
if (is_valid == false) {
return {false, result};
}
if (form_size > proof_blob_len) return {false, result};
form proof = DeserializeForm(D, proof_blob, form_size);
form y_result;
if (VerifyWesoSegment(D, x, proof, B, iterations, y_result) == -1) {
Expand All @@ -129,10 +141,10 @@ std::pair<bool, std::vector<uint8_t>> CheckProofOfTimeNWesolowskiWithB(integer D
return {true, result};
}

// TODO: Perhaps move?
integer GetBFromProof(integer D, const uint8_t* x_s, const uint8_t* proof_blob, int32_t proof_blob_len, uint64_t iterations, int32_t depth) {
int form_size = BQFC_FORM_SIZE;
int segment_len = 8 + B_bytes + form_size;
if (x_s == nullptr || proof_blob == nullptr) throw std::runtime_error("Invalid proof.");
form x = DeserializeForm(D, x_s, form_size);
if (proof_blob_len != 2 * form_size + depth * segment_len) {
throw std::runtime_error("Invalid proof.");
Expand All @@ -141,6 +153,7 @@ integer GetBFromProof(integer D, const uint8_t* x_s, const uint8_t* proof_blob,
if (is_valid == false) {
throw std::runtime_error("Invalid proof.");
}
if (form_size > proof_blob_len) throw std::runtime_error("Invalid proof.");
form y = DeserializeForm(D, proof_blob, form_size);
return GetB(D, x, y);
}
Expand Down
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