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-rw-r--r--src/key.cpp77
1 files changed, 55 insertions, 22 deletions
diff --git a/src/key.cpp b/src/key.cpp
index 9d4c4498d8..f8136f88b5 100644
--- a/src/key.cpp
+++ b/src/key.cpp
@@ -1,4 +1,5 @@
-// Copyright (c) 2009-2016 The Bitcoin Core developers
+// Copyright (c) 2009-2017 The Bitcoin Core developers
+// Copyright (c) 2017 The Zcash developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
@@ -15,43 +16,62 @@
static secp256k1_context* secp256k1_context_sign = nullptr;
/** These functions are taken from the libsecp256k1 distribution and are very ugly. */
+
+/**
+ * This parses a format loosely based on a DER encoding of the ECPrivateKey type from
+ * section C.4 of SEC 1 <http://www.secg.org/sec1-v2.pdf>, with the following caveats:
+ *
+ * * The octet-length of the SEQUENCE must be encoded as 1 or 2 octets. It is not
+ * required to be encoded as one octet if it is less than 256, as DER would require.
+ * * The octet-length of the SEQUENCE must not be greater than the remaining
+ * length of the key encoding, but need not match it (i.e. the encoding may contain
+ * junk after the encoded SEQUENCE).
+ * * The privateKey OCTET STRING is zero-filled on the left to 32 octets.
+ * * Anything after the encoding of the privateKey OCTET STRING is ignored, whether
+ * or not it is validly encoded DER.
+ *
+ * out32 must point to an output buffer of length at least 32 bytes.
+ */
static int ec_privkey_import_der(const secp256k1_context* ctx, unsigned char *out32, const unsigned char *privkey, size_t privkeylen) {
const unsigned char *end = privkey + privkeylen;
- int lenb = 0;
- int len = 0;
memset(out32, 0, 32);
/* sequence header */
- if (end < privkey+1 || *privkey != 0x30) {
+ if (end - privkey < 1 || *privkey != 0x30u) {
return 0;
}
privkey++;
/* sequence length constructor */
- if (end < privkey+1 || !(*privkey & 0x80)) {
+ if (end - privkey < 1 || !(*privkey & 0x80u)) {
return 0;
}
- lenb = *privkey & ~0x80; privkey++;
+ size_t lenb = *privkey & ~0x80u; privkey++;
if (lenb < 1 || lenb > 2) {
return 0;
}
- if (end < privkey+lenb) {
+ if (end - privkey < lenb) {
return 0;
}
/* sequence length */
- len = privkey[lenb-1] | (lenb > 1 ? privkey[lenb-2] << 8 : 0);
+ size_t len = privkey[lenb-1] | (lenb > 1 ? privkey[lenb-2] << 8 : 0u);
privkey += lenb;
- if (end < privkey+len) {
+ if (end - privkey < len) {
return 0;
}
/* sequence element 0: version number (=1) */
- if (end < privkey+3 || privkey[0] != 0x02 || privkey[1] != 0x01 || privkey[2] != 0x01) {
+ if (end - privkey < 3 || privkey[0] != 0x02u || privkey[1] != 0x01u || privkey[2] != 0x01u) {
return 0;
}
privkey += 3;
/* sequence element 1: octet string, up to 32 bytes */
- if (end < privkey+2 || privkey[0] != 0x04 || privkey[1] > 0x20 || end < privkey+2+privkey[1]) {
+ if (end - privkey < 2 || privkey[0] != 0x04u) {
+ return 0;
+ }
+ size_t oslen = privkey[1];
+ privkey += 2;
+ if (oslen > 32 || end - privkey < oslen) {
return 0;
}
- memcpy(out32 + 32 - privkey[1], privkey + 2, privkey[1]);
+ memcpy(out32 + (32 - oslen), privkey, oslen);
if (!secp256k1_ec_seckey_verify(ctx, out32)) {
memset(out32, 0, 32);
return 0;
@@ -59,7 +79,18 @@ static int ec_privkey_import_der(const secp256k1_context* ctx, unsigned char *ou
return 1;
}
+/**
+ * This serializes to a DER encoding of the ECPrivateKey type from section C.4 of SEC 1
+ * <http://www.secg.org/sec1-v2.pdf>. The optional parameters and publicKey fields are
+ * included.
+ *
+ * privkey must point to an output buffer of length at least CKey::PRIVATE_KEY_SIZE bytes.
+ * privkeylen must initially be set to the size of the privkey buffer. Upon return it
+ * will be set to the number of bytes used in the buffer.
+ * key32 must point to a 32-byte raw private key.
+ */
static int ec_privkey_export_der(const secp256k1_context *ctx, unsigned char *privkey, size_t *privkeylen, const unsigned char *key32, int compressed) {
+ assert(*privkeylen >= CKey::PRIVATE_KEY_SIZE);
secp256k1_pubkey pubkey;
size_t pubkeylen = 0;
if (!secp256k1_ec_pubkey_create(ctx, &pubkey, key32)) {
@@ -85,10 +116,11 @@ static int ec_privkey_export_der(const secp256k1_context *ctx, unsigned char *pr
memcpy(ptr, begin, sizeof(begin)); ptr += sizeof(begin);
memcpy(ptr, key32, 32); ptr += 32;
memcpy(ptr, middle, sizeof(middle)); ptr += sizeof(middle);
- pubkeylen = 33;
+ pubkeylen = CPubKey::COMPRESSED_PUBLIC_KEY_SIZE;
secp256k1_ec_pubkey_serialize(ctx, ptr, &pubkeylen, &pubkey, SECP256K1_EC_COMPRESSED);
ptr += pubkeylen;
*privkeylen = ptr - privkey;
+ assert(*privkeylen == CKey::COMPRESSED_PRIVATE_KEY_SIZE);
} else {
static const unsigned char begin[] = {
0x30,0x82,0x01,0x13,0x02,0x01,0x01,0x04,0x20
@@ -110,10 +142,11 @@ static int ec_privkey_export_der(const secp256k1_context *ctx, unsigned char *pr
memcpy(ptr, begin, sizeof(begin)); ptr += sizeof(begin);
memcpy(ptr, key32, 32); ptr += 32;
memcpy(ptr, middle, sizeof(middle)); ptr += sizeof(middle);
- pubkeylen = 65;
+ pubkeylen = CPubKey::PUBLIC_KEY_SIZE;
secp256k1_ec_pubkey_serialize(ctx, ptr, &pubkeylen, &pubkey, SECP256K1_EC_UNCOMPRESSED);
ptr += pubkeylen;
*privkeylen = ptr - privkey;
+ assert(*privkeylen == CKey::PRIVATE_KEY_SIZE);
}
return 1;
}
@@ -135,8 +168,8 @@ CPrivKey CKey::GetPrivKey() const {
CPrivKey privkey;
int ret;
size_t privkeylen;
- privkey.resize(279);
- privkeylen = 279;
+ privkey.resize(PRIVATE_KEY_SIZE);
+ privkeylen = PRIVATE_KEY_SIZE;
ret = ec_privkey_export_der(secp256k1_context_sign, (unsigned char*) privkey.data(), &privkeylen, begin(), fCompressed ? SECP256K1_EC_COMPRESSED : SECP256K1_EC_UNCOMPRESSED);
assert(ret);
privkey.resize(privkeylen);
@@ -146,7 +179,7 @@ CPrivKey CKey::GetPrivKey() const {
CPubKey CKey::GetPubKey() const {
assert(fValid);
secp256k1_pubkey pubkey;
- size_t clen = 65;
+ size_t clen = CPubKey::PUBLIC_KEY_SIZE;
CPubKey result;
int ret = secp256k1_ec_pubkey_create(secp256k1_context_sign, &pubkey, begin());
assert(ret);
@@ -159,8 +192,8 @@ CPubKey CKey::GetPubKey() const {
bool CKey::Sign(const uint256 &hash, std::vector<unsigned char>& vchSig, uint32_t test_case) const {
if (!fValid)
return false;
- vchSig.resize(72);
- size_t nSigLen = 72;
+ vchSig.resize(CPubKey::SIGNATURE_SIZE);
+ size_t nSigLen = CPubKey::SIGNATURE_SIZE;
unsigned char extra_entropy[32] = {0};
WriteLE32(extra_entropy, test_case);
secp256k1_ecdsa_signature sig;
@@ -188,7 +221,7 @@ bool CKey::VerifyPubKey(const CPubKey& pubkey) const {
bool CKey::SignCompact(const uint256 &hash, std::vector<unsigned char>& vchSig) const {
if (!fValid)
return false;
- vchSig.resize(65);
+ vchSig.resize(CPubKey::COMPACT_SIGNATURE_SIZE);
int rec = -1;
secp256k1_ecdsa_recoverable_signature sig;
int ret = secp256k1_ecdsa_sign_recoverable(secp256k1_context_sign, &sig, hash.begin(), begin(), secp256k1_nonce_function_rfc6979, nullptr);
@@ -218,10 +251,10 @@ bool CKey::Derive(CKey& keyChild, ChainCode &ccChild, unsigned int nChild, const
std::vector<unsigned char, secure_allocator<unsigned char>> vout(64);
if ((nChild >> 31) == 0) {
CPubKey pubkey = GetPubKey();
- assert(pubkey.begin() + 33 == pubkey.end());
+ assert(pubkey.size() == CPubKey::COMPRESSED_PUBLIC_KEY_SIZE);
BIP32Hash(cc, nChild, *pubkey.begin(), pubkey.begin()+1, vout.data());
} else {
- assert(begin() + 32 == end());
+ assert(size() == 32);
BIP32Hash(cc, nChild, 0, begin(), vout.data());
}
memcpy(ccChild.begin(), vout.data()+32, 32);
generated by cgit v1.2.3 (git 2.26.2) at 2024-08-27 12:14:31 +0000