diff options
Diffstat (limited to 'Godeps/_workspace/src/github.com/ethereum')
4 files changed, 52 insertions, 17 deletions
diff --git a/Godeps/_workspace/src/github.com/ethereum/ethash/ethash.go b/Godeps/_workspace/src/github.com/ethereum/ethash/ethash.go index 73c5bf664..d0864da7f 100644 --- a/Godeps/_workspace/src/github.com/ethereum/ethash/ethash.go +++ b/Godeps/_workspace/src/github.com/ethereum/ethash/ethash.go @@ -100,19 +100,29 @@ type Light struct { func (l *Light) Verify(block pow.Block) bool { // TODO: do ethash_quick_verify before getCache in order // to prevent DOS attacks. - var ( - blockNum = block.NumberU64() - difficulty = block.Difficulty() - cache = l.getCache(blockNum) - dagSize = C.ethash_get_datasize(C.uint64_t(blockNum)) - ) - if l.test { - dagSize = dagSizeForTesting - } + blockNum := block.NumberU64() if blockNum >= epochLength*2048 { glog.V(logger.Debug).Infof("block number %d too high, limit is %d", epochLength*2048) return false } + + difficulty := block.Difficulty() + /* Cannot happen if block header diff is validated prior to PoW, but can + happen if PoW is checked first due to parallel PoW checking. + We could check the minimum valid difficulty but for SoC we avoid (duplicating) + Ethereum protocol consensus rules here which are not in scope of Ethash + */ + if difficulty.Cmp(common.Big0) == 0 { + glog.V(logger.Debug).Infof("invalid block difficulty") + return false + } + + cache := l.getCache(blockNum) + dagSize := C.ethash_get_datasize(C.uint64_t(blockNum)) + + if l.test { + dagSize = dagSizeForTesting + } // Recompute the hash using the cache. hash := hashToH256(block.HashNoNonce()) ret := C.ethash_light_compute_internal(cache.ptr, dagSize, hash, C.uint64_t(block.Nonce())) diff --git a/Godeps/_workspace/src/github.com/ethereum/ethash/ethash_test.go b/Godeps/_workspace/src/github.com/ethereum/ethash/ethash_test.go index e6833e343..1e1de989d 100644 --- a/Godeps/_workspace/src/github.com/ethereum/ethash/ethash_test.go +++ b/Godeps/_workspace/src/github.com/ethereum/ethash/ethash_test.go @@ -11,6 +11,7 @@ import ( "testing" "github.com/ethereum/go-ethereum/common" + "github.com/ethereum/go-ethereum/crypto" ) func init() { @@ -59,6 +60,14 @@ var validBlocks = []*testBlock{ }, } +var invalidZeroDiffBlock = testBlock{ + number: 61440000, + hashNoNonce: crypto.Sha3Hash([]byte("foo")), + difficulty: big.NewInt(0), + nonce: 0xcafebabec00000fe, + mixDigest: crypto.Sha3Hash([]byte("bar")), +} + func TestEthashVerifyValid(t *testing.T) { eth := New() for i, block := range validBlocks { @@ -68,6 +77,13 @@ func TestEthashVerifyValid(t *testing.T) { } } +func TestEthashVerifyInvalid(t *testing.T) { + eth := New() + if eth.Verify(&invalidZeroDiffBlock) { + t.Errorf("should not validate - we just ensure it does not panic on this block") + } +} + func TestEthashConcurrentVerify(t *testing.T) { eth, err := NewForTesting() if err != nil { diff --git a/Godeps/_workspace/src/github.com/ethereum/ethash/src/libethash/internal.c b/Godeps/_workspace/src/github.com/ethereum/ethash/src/libethash/internal.c index b28a59e43..338aa5ecd 100644 --- a/Godeps/_workspace/src/github.com/ethereum/ethash/src/libethash/internal.c +++ b/Godeps/_workspace/src/github.com/ethereum/ethash/src/libethash/internal.c @@ -284,13 +284,13 @@ bool ethash_quick_check_difficulty( ethash_h256_t const* header_hash, uint64_t const nonce, ethash_h256_t const* mix_hash, - ethash_h256_t const* difficulty + ethash_h256_t const* boundary ) { ethash_h256_t return_hash; ethash_quick_hash(&return_hash, header_hash, nonce, mix_hash); - return ethash_check_difficulty(&return_hash, difficulty); + return ethash_check_difficulty(&return_hash, boundary); } ethash_light_t ethash_light_new_internal(uint64_t cache_size, ethash_h256_t const* seed) diff --git a/Godeps/_workspace/src/github.com/ethereum/ethash/src/libethash/internal.h b/Godeps/_workspace/src/github.com/ethereum/ethash/src/libethash/internal.h index 4e2b695ac..26c395ad6 100644 --- a/Godeps/_workspace/src/github.com/ethereum/ethash/src/libethash/internal.h +++ b/Godeps/_workspace/src/github.com/ethereum/ethash/src/libethash/internal.h @@ -46,27 +46,36 @@ static inline void ethash_h256_reset(ethash_h256_t* hash) memset(hash, 0, 32); } -// Returns if hash is less than or equal to difficulty +// Returns if hash is less than or equal to boundary (2^256/difficulty) static inline bool ethash_check_difficulty( ethash_h256_t const* hash, - ethash_h256_t const* difficulty + ethash_h256_t const* boundary ) { - // Difficulty is big endian + // Boundary is big endian for (int i = 0; i < 32; i++) { - if (ethash_h256_get(hash, i) == ethash_h256_get(difficulty, i)) { + if (ethash_h256_get(hash, i) == ethash_h256_get(boundary, i)) { continue; } - return ethash_h256_get(hash, i) < ethash_h256_get(difficulty, i); + return ethash_h256_get(hash, i) < ethash_h256_get(boundary, i); } return true; } +/** + * Difficulty quick check for POW preverification + * + * @param header_hash The hash of the header + * @param nonce The block's nonce + * @param mix_hash The mix digest hash + * @param boundary The boundary is defined as (2^256 / difficulty) + * @return true for succesful pre-verification and false otherwise + */ bool ethash_quick_check_difficulty( ethash_h256_t const* header_hash, uint64_t const nonce, ethash_h256_t const* mix_hash, - ethash_h256_t const* difficulty + ethash_h256_t const* boundary ); struct ethash_light { |