Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Add fix for matchBytes32Prefix #24

Merged
merged 4 commits into from
Dec 5, 2017
Merged

Add fix for matchBytes32Prefix #24

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
69795b0
Add fix for matchBytes32Prefix
Dec 1, 2017
de5e5b8
More efficient way
Dec 5, 2017
4bfbb59
Fix typo
Dec 5, 2017
eced7ce
Adds missing / in comment
Dec 5, 2017
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
19 changes: 6 additions & 13 deletions oraclizeAPI_0.4.sol
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -871,35 +871,29 @@ contract usingOraclize {
return 0;
}

function matchBytes32Prefix(bytes32 content, bytes prefix) internal returns (bool){
function matchBytes32Prefix(bytes32 content, bytes prefix, uint n_random_bytes) internal returns (bool){
bool match_ = true;

for (var i=0; i<prefix.length; i++){
for (var i=0; i< n_random_bytes; i++) {
Copy link
Contributor

@D-Nice D-Nice Dec 5, 2017 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

if n_random_bytes exceeds 255, this loop will overflow, consider using uint256 over var, if there's no other overflow or length checks on n_random_bytes

if (content[i] != prefix[i]) match_ = false;
}

return match_;
}

function oraclize_randomDS_proofVerify__main(bytes proof, bytes32 queryId, bytes result, string context_name) internal returns (bool){
bool checkok;


// Step 2: the unique keyhash has to match with the sha256 of (context name + queryId)
uint ledgerProofLength = 3+65+(uint(proof[3+65+1])+2)+32;
bytes memory keyhash = new bytes(32);
copyBytes(proof, ledgerProofLength, 32, keyhash, 0);
checkok = (sha3(keyhash) == sha3(sha256(context_name, queryId)));
if (checkok == false) return false;
if (!(sha3(keyhash) == sha3(sha256(context_name, queryId)))) return false;

bytes memory sig1 = new bytes(uint(proof[ledgerProofLength+(32+8+1+32)+1])+2);
copyBytes(proof, ledgerProofLength+(32+8+1+32), sig1.length, sig1, 0);


// Step 3: we assume sig1 is valid (it will be verified during step 5) and we verify if 'result' is the prefix of sha256(sig1)
checkok = matchBytes32Prefix(sha256(sig1), result);
if (checkok == false) return false;

if (!matchBytes32Prefix(sha256(sig1), result, uint(proof[ledgerProofLength+32+8]))) return false;

// Step 4: commitment match verification, sha3(delay, nbytes, unonce, sessionKeyHash) == commitment in storage.
// This is to verify that the computed args match with the ones specified in the query.
Expand All @@ -919,8 +913,7 @@ contract usingOraclize {
// Step 5: validity verification for sig1 (keyhash and args signed with the sessionKey)
bytes memory tosign1 = new bytes(32+8+1+32);
copyBytes(proof, ledgerProofLength, 32+8+1+32, tosign1, 0);
checkok = verifySig(sha256(tosign1), sig1, sessionPubkey);
if (checkok == false) return false;
if (!verifySig(sha256(tosign1), sig1, sessionPubkey)) return false;

// verify if sessionPubkeyHash was verified already, if not.. let's do it!
if (oraclize_randomDS_sessionKeysHashVerified[sessionPubkeyHash] == false){
Expand Down
19 changes: 6 additions & 13 deletions oraclizeAPI_0.5.sol
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -868,35 +868,30 @@ contract usingOraclize {
return 0;
}

function matchBytes32Prefix(bytes32 content, bytes prefix) internal pure returns (bool){
function matchBytes32Prefix(bytes32 content, bytes prefix, uint n_random_bytes) internal pure returns (bool){
bool match_ = true;


for (uint256 i=0; i<prefix.length; i++){
for (uint256 i=0; i< n_random_bytes; i++) {
if (content[i] != prefix[i]) match_ = false;
}

return match_;
}

function oraclize_randomDS_proofVerify__main(bytes proof, bytes32 queryId, bytes result, string context_name) internal returns (bool){
bool checkok;


// Step 2: the unique keyhash has to match with the sha256 of (context name + queryId)
uint ledgerProofLength = 3+65+(uint(proof[3+65+1])+2)+32;
bytes memory keyhash = new bytes(32);
copyBytes(proof, ledgerProofLength, 32, keyhash, 0);
checkok = (keccak256(keyhash) == keccak256(sha256(context_name, queryId)));
if (checkok == false) return false;
if (!(keccak256(keyhash) == keccak256(sha256(context_name, queryId)))) return false;

bytes memory sig1 = new bytes(uint(proof[ledgerProofLength+(32+8+1+32)+1])+2);
copyBytes(proof, ledgerProofLength+(32+8+1+32), sig1.length, sig1, 0);


// Step 3: we assume sig1 is valid (it will be verified during step 5) and we verify if 'result' is the prefix of sha256(sig1)
checkok = matchBytes32Prefix(sha256(sig1), result);
if (checkok == false) return false;

if (!matchBytes32Prefix(sha256(sig1), result, uint(proof[ledgerProofLength+32+8]))) return false;

// Step 4: commitment match verification, keccak256(delay, nbytes, unonce, sessionKeyHash) == commitment in storage.
// This is to verify that the computed args match with the ones specified in the query.
Expand All @@ -916,8 +911,7 @@ contract usingOraclize {
// Step 5: validity verification for sig1 (keyhash and args signed with the sessionKey)
bytes memory tosign1 = new bytes(32+8+1+32);
copyBytes(proof, ledgerProofLength, 32+8+1+32, tosign1, 0);
checkok = verifySig(sha256(tosign1), sig1, sessionPubkey);
if (checkok == false) return false;
if (!verifySig(sha256(tosign1), sig1, sessionPubkey)) return false;

// verify if sessionPubkeyHash was verified already, if not.. let's do it!
if (oraclize_randomDS_sessionKeysHashVerified[sessionPubkeyHash] == false){
Expand All @@ -927,7 +921,6 @@ contract usingOraclize {
return oraclize_randomDS_sessionKeysHashVerified[sessionPubkeyHash];
}


// the following function has been written by Alex Beregszaszi (@axic), use it under the terms of the MIT license
function copyBytes(bytes from, uint fromOffset, uint length, bytes to, uint toOffset) internal pure returns (bytes) {
uint minLength = length + toOffset;
Expand Down