X-Git-Url: https://git.novaco.in/?a=blobdiff_plain;f=src%2Fkey.cpp;h=e95fb1764c843563145f4455b890dfc515cb490c;hb=13369afc225fd435b7d3649b048e7233341f292a;hp=b6c3f2868825f7b506aaf3b240a822eb09c50483;hpb=fcbeaff8d049e414284631989b950e56b909525c;p=novacoin.git

diff --git a/src/key.cpp b/src/key.cpp
index b6c3f28..e95fb17 100644
--- a/src/key.cpp
+++ b/src/key.cpp
@@ -1,6 +1,6 @@
 // Copyright (c) 2009-2012 The Bitcoin developers
 // Distributed under the MIT/X11 software license, see the accompanying
-// file license.txt or http://www.opensource.org/licenses/mit-license.php.
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <map>
 
@@ -8,7 +8,6 @@
 #include <openssl/obj_mac.h>
 
 #include "key.h"
-#include "util.h"
 
 // Generate a private key from just the secret parameter
 int EC_KEY_regenerate_key(EC_KEY *eckey, BIGNUM *priv_key)
@@ -49,7 +48,7 @@ err:
 
 // Perform ECDSA key recovery (see SEC1 4.1.6) for curves over (mod p)-fields
 // recid selects which key is recovered
-// if check is nonzero, additional checks are performed
+// if check is non-zero, additional checks are performed
 int ECDSA_SIG_recover_key_GFp(EC_KEY *eckey, ECDSA_SIG *ecsig, const unsigned char *msg, int msglen, int recid, int check)
 {
     if (!eckey) return 0;
@@ -121,6 +120,51 @@ err:
     return ret;
 }
 
+int CompareBigEndian(const unsigned char *c1, size_t c1len, const unsigned char *c2, size_t c2len) {
+    while (c1len > c2len) {
+        if (*c1)
+            return 1;
+        c1++;
+        c1len--;
+    }
+    while (c2len > c1len) {
+        if (*c2)
+            return -1;
+        c2++;
+        c2len--;
+    }
+    while (c1len > 0) {
+        if (*c1 > *c2)
+            return 1;
+        if (*c2 > *c1)
+            return -1;
+        c1++;
+        c2++;
+        c1len--;
+    }
+    return 0;
+}
+
+// Order of secp256k1's generator minus 1.
+const unsigned char vchMaxModOrder[32] = {
+    0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
+    0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFE,
+    0xBA,0xAE,0xDC,0xE6,0xAF,0x48,0xA0,0x3B,
+    0xBF,0xD2,0x5E,0x8C,0xD0,0x36,0x41,0x40
+};
+
+// Half of the order of secp256k1's generator minus 1.
+const unsigned char vchMaxModHalfOrder[32] = {
+    0x7F,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
+    0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
+    0x5D,0x57,0x6E,0x73,0x57,0xA4,0x50,0x1D,
+    0xDF,0xE9,0x2F,0x46,0x68,0x1B,0x20,0xA0
+};
+
+const unsigned char *vchZero = NULL;
+
+
+
 void CKey::SetCompressedPubKey()
 {
     EC_KEY_set_conv_form(pkey, POINT_CONVERSION_COMPRESSED);
@@ -130,6 +174,8 @@ void CKey::SetCompressedPubKey()
 void CKey::Reset()
 {
     fCompressedPubKey = false;
+    if (pkey != NULL)
+        EC_KEY_free(pkey);
     pkey = EC_KEY_new_by_curve_name(NID_secp256k1);
     if (pkey == NULL)
         throw key_error("CKey::CKey() : EC_KEY_new_by_curve_name failed");
@@ -138,6 +184,7 @@ void CKey::Reset()
 
 CKey::CKey()
 {
+    pkey = NULL;
     Reset();
 }
 
@@ -147,6 +194,7 @@ CKey::CKey(const CKey& b)
     if (pkey == NULL)
         throw key_error("CKey::CKey(const CKey&) : EC_KEY_dup failed");
     fSet = b.fSet;
+    fCompressedPubKey = b.fCompressedPubKey;
 }
 
 CKey& CKey::operator=(const CKey& b)
@@ -154,6 +202,7 @@ CKey& CKey::operator=(const CKey& b)
     if (!EC_KEY_copy(pkey, b.pkey))
         throw key_error("CKey::operator=(const CKey&) : EC_KEY_copy failed");
     fSet = b.fSet;
+    fCompressedPubKey = b.fCompressedPubKey;
     return (*this);
 }
 
@@ -172,6 +221,37 @@ bool CKey::IsCompressed() const
     return fCompressedPubKey;
 }
 
+bool CKey::CheckSignatureElement(const unsigned char *vch, int len, bool half) {
+    return CompareBigEndian(vch, len, vchZero, 0) > 0 &&
+        CompareBigEndian(vch, len, half ? vchMaxModHalfOrder : vchMaxModOrder, 32) <= 0;
+}
+
+bool CKey::ReserealizeSignature(std::vector<unsigned char>& vchSig)
+{
+    if (vchSig.empty())
+        return false;
+
+    unsigned char *pos = &vchSig[0];
+    ECDSA_SIG *sig = d2i_ECDSA_SIG(NULL, (const unsigned char **)&pos, vchSig.size());
+    if (sig == NULL)
+        return false;
+
+    bool ret = false;
+    int nSize = i2d_ECDSA_SIG(sig, NULL);
+    if (nSize > 0) {
+        vchSig.resize(nSize); // grow or shrink as needed
+
+        pos = &vchSig[0];
+        i2d_ECDSA_SIG(sig, &pos);
+
+        ret = true;
+    }
+
+    ECDSA_SIG_free(sig);
+
+    return ret;
+}
+
 void CKey::MakeNewKey(bool fCompressed)
 {
     if (!EC_KEY_generate_key(pkey))
@@ -184,10 +264,24 @@ void CKey::MakeNewKey(bool fCompressed)
 bool CKey::SetPrivKey(const CPrivKey& vchPrivKey)
 {
     const unsigned char* pbegin = &vchPrivKey[0];
-    if (!d2i_ECPrivateKey(&pkey, &pbegin, vchPrivKey.size()))
-        return false;
-    fSet = true;
-    return true;
+    if (d2i_ECPrivateKey(&pkey, &pbegin, vchPrivKey.size()))
+    {
+        // In testing, d2i_ECPrivateKey can return true
+        // but fill in pkey with a key that fails
+        // EC_KEY_check_key, so:
+        if (EC_KEY_check_key(pkey))
+        {
+            fSet = true;
+            return true;
+        }
+    }
+    // If vchPrivKey data is bad d2i_ECPrivateKey() can
+    // leave pkey in a state where calling EC_KEY_free()
+    // crashes. To avoid that, set pkey to NULL and
+    // leak the memory (a leak is better than a crash)
+    pkey = NULL;
+    Reset();
+    return false;
 }
 
 bool CKey::SetSecret(const CSecret& vchSecret, bool fCompressed)
@@ -240,18 +334,22 @@ CPrivKey CKey::GetPrivKey() const
     return vchPrivKey;
 }
 
-bool CKey::SetPubKey(const std::vector<unsigned char>& vchPubKey)
+bool CKey::SetPubKey(const CPubKey& vchPubKey)
 {
-    const unsigned char* pbegin = &vchPubKey[0];
-    if (!o2i_ECPublicKey(&pkey, &pbegin, vchPubKey.size()))
-        return false;
-    fSet = true;
-    if (vchPubKey.size() == 33)
-        SetCompressedPubKey();
-    return true;
+    const unsigned char* pbegin = &vchPubKey.vchPubKey[0];
+    if (o2i_ECPublicKey(&pkey, &pbegin, vchPubKey.vchPubKey.size()))
+    {
+        fSet = true;
+        if (vchPubKey.vchPubKey.size() == 33)
+            SetCompressedPubKey();
+        return true;
+    }
+    pkey = NULL;
+    Reset();
+    return false;
 }
 
-std::vector<unsigned char> CKey::GetPubKey() const
+CPubKey CKey::GetPubKey() const
 {
     int nSize = i2o_ECPublicKey(pkey, NULL);
     if (!nSize)
@@ -260,19 +358,34 @@ std::vector<unsigned char> CKey::GetPubKey() const
     unsigned char* pbegin = &vchPubKey[0];
     if (i2o_ECPublicKey(pkey, &pbegin) != nSize)
         throw key_error("CKey::GetPubKey() : i2o_ECPublicKey returned unexpected size");
-    return vchPubKey;
+    return CPubKey(vchPubKey);
 }
 
 bool CKey::Sign(uint256 hash, std::vector<unsigned char>& vchSig)
 {
+    vchSig.clear();
+    ECDSA_SIG *sig = ECDSA_do_sign((unsigned char*)&hash, sizeof(hash), pkey);
+    if (sig==NULL)
+        return false;
+    const EC_GROUP *group = EC_KEY_get0_group(pkey);
+    CBigNum order, halforder;
+    EC_GROUP_get_order(group, &order, NULL);
+    BN_rshift1(&halforder, &order);
+    // enforce low S values, by negating the value (modulo the order) if above order/2.
+    if (BN_cmp(sig->s, &halforder) > 0) {
+        BN_sub(sig->s, &order, sig->s);
+    }
     unsigned int nSize = ECDSA_size(pkey);
     vchSig.resize(nSize); // Make sure it is big enough
-    if (!ECDSA_sign(0, (unsigned char*)&hash, sizeof(hash), &vchSig[0], &nSize, pkey))
-    {
+    unsigned char *pos = &vchSig[0];
+    nSize = i2d_ECDSA_SIG(sig, &pos);
+    ECDSA_SIG_free(sig);
+    vchSig.resize(nSize); // Shrink to fit actual size
+    // Testing our new signature
+    if (ECDSA_verify(0, (unsigned char*)&hash, sizeof(hash), &vchSig[0], vchSig.size(), pkey) != 1) {
         vchSig.clear();
         return false;
     }
-    vchSig.resize(nSize); // Shrink to fit actual size
     return true;
 }
 
@@ -286,14 +399,22 @@ bool CKey::SignCompact(uint256 hash, std::vector<unsigned char>& vchSig)
     ECDSA_SIG *sig = ECDSA_do_sign((unsigned char*)&hash, sizeof(hash), pkey);
     if (sig==NULL)
         return false;
+    const EC_GROUP *group = EC_KEY_get0_group(pkey);
+    CBigNum order, halforder;
+    EC_GROUP_get_order(group, &order, NULL);
+    BN_rshift1(&halforder, &order);
+    // enforce low S values, by negating the value (modulo the order) if above order/2.
+    if (BN_cmp(sig->s, &halforder) > 0) {
+        BN_sub(sig->s, &order, sig->s);
+    }
     vchSig.clear();
     vchSig.resize(65,0);
     int nBitsR = BN_num_bits(sig->r);
     int nBitsS = BN_num_bits(sig->s);
     if (nBitsR <= 256 && nBitsS <= 256)
     {
-        int nRecId = -1;
-        for (int i=0; i<4; i++)
+        int8_t nRecId = -1;
+        for (int8_t i=0; i<4; i++)
         {
             CKey keyRec;
             keyRec.fSet = true;
@@ -308,7 +429,10 @@ bool CKey::SignCompact(uint256 hash, std::vector<unsigned char>& vchSig)
         }
 
         if (nRecId == -1)
+        {
+            ECDSA_SIG_free(sig);
             throw key_error("CKey::SignCompact() : unable to construct recoverable key");
+        }
 
         vchSig[0] = nRecId+27+(fCompressedPubKey ? 4 : 0);
         BN_bn2bin(sig->r,&vchSig[33-(nBitsR+7)/8]);
@@ -347,16 +471,40 @@ bool CKey::SetCompactSignature(uint256 hash, const std::vector<unsigned char>& v
         ECDSA_SIG_free(sig);
         return true;
     }
+    ECDSA_SIG_free(sig);
     return false;
 }
 
 bool CKey::Verify(uint256 hash, const std::vector<unsigned char>& vchSig)
 {
-    // -1 = error, 0 = bad sig, 1 = good
-    if (ECDSA_verify(0, (unsigned char*)&hash, sizeof(hash), &vchSig[0], vchSig.size(), pkey) != 1)
+    if (vchSig.empty())
         return false;
 
-    return true;
+    // New versions of OpenSSL will reject non-canonical DER signatures. de/re-serialize first.
+    unsigned char *norm_der = NULL;
+    ECDSA_SIG *norm_sig = ECDSA_SIG_new();
+    const unsigned char* sigptr = &vchSig[0];
+    assert(norm_sig);
+    if (d2i_ECDSA_SIG(&norm_sig, &sigptr, vchSig.size()) == NULL)
+    {
+        /* As of OpenSSL 1.0.0p d2i_ECDSA_SIG frees and nulls the pointer on
+        * error. But OpenSSL's own use of this function redundantly frees the
+        * result. As ECDSA_SIG_free(NULL) is a no-op, and in the absence of a
+        * clear contract for the function behaving the same way is more
+        * conservative.
+        */
+        ECDSA_SIG_free(norm_sig);
+        return false;
+    }
+    int derlen = i2d_ECDSA_SIG(norm_sig, &norm_der);
+    ECDSA_SIG_free(norm_sig);
+    if (derlen <= 0)
+        return false;
+
+    // -1 = error, 0 = bad sig, 1 = good
+    bool ret = ECDSA_verify(0, (unsigned char*)&hash, sizeof(hash), norm_der, derlen, pkey) == 1;
+    OPENSSL_free(norm_der);
+    return ret;
 }
 
 bool CKey::VerifyCompact(uint256 hash, const std::vector<unsigned char>& vchSig)
@@ -375,6 +523,9 @@ bool CKey::IsValid()
     if (!fSet)
         return false;
 
+    if (!EC_KEY_check_key(pkey))
+        return false;
+
     bool fCompr;
     CSecret secret = GetSecret(fCompr);
     CKey key2;