1 files changed, 193 insertions, 0 deletions
diff --git a/src/wallet/ismine.cpp b/src/wallet/ismine.cpp
new file mode 100644
index 0000000000..c5aad5f27c
--- /dev/null
+++ b/src/wallet/ismine.cpp
@@ -0,0 +1,193 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2018 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <wallet/ismine.h>
+
+#include <key.h>
+#include <keystore.h>
+#include <script/script.h>
+#include <script/sign.h>
+
+
+typedef std::vector<unsigned char> valtype;
+
+namespace {
+
+/**
+ * This is an enum that tracks the execution context of a script, similar to
+ * SigVersion in script/interpreter. It is separate however because we want to
+ * distinguish between top-level scriptPubKey execution and P2SH redeemScript
+ * execution (a distinction that has no impact on consensus rules).
+ */
+enum class IsMineSigVersion
+{
+    TOP = 0,        //!< scriptPubKey execution
+    P2SH = 1,       //!< P2SH redeemScript
+    WITNESS_V0 = 2, //!< P2WSH witness script execution
+};
+
+/**
+ * This is an internal representation of isminetype + invalidity.
+ * Its order is significant, as we return the max of all explored
+ * possibilities.
+ */
+enum class IsMineResult
+{
+    NO = 0,         //!< Not ours
+    WATCH_ONLY = 1, //!< Included in watch-only balance
+    SPENDABLE = 2,  //!< Included in all balances
+    INVALID = 3,    //!< Not spendable by anyone (uncompressed pubkey in segwit, P2SH inside P2SH or witness, witness inside witness)
+};
+
+bool PermitsUncompressed(IsMineSigVersion sigversion)
+{
+    return sigversion == IsMineSigVersion::TOP || sigversion == IsMineSigVersion::P2SH;
+}
+
+bool HaveKeys(const std::vector<valtype>& pubkeys, const CKeyStore& keystore)
+{
+    for (const valtype& pubkey : pubkeys) {
+        CKeyID keyID = CPubKey(pubkey).GetID();
+        if (!keystore.HaveKey(keyID)) return false;
+    }
+    return true;
+}
+
+IsMineResult IsMineInner(const CKeyStore& keystore, const CScript& scriptPubKey, IsMineSigVersion sigversion)
+{
+    IsMineResult ret = IsMineResult::NO;
+
+    std::vector<valtype> vSolutions;
+    txnouttype whichType = Solver(scriptPubKey, vSolutions);
+
+    CKeyID keyID;
+    switch (whichType)
+    {
+    case TX_NONSTANDARD:
+    case TX_NULL_DATA:
+    case TX_WITNESS_UNKNOWN:
+        break;
+    case TX_PUBKEY:
+        keyID = CPubKey(vSolutions[0]).GetID();
+        if (!PermitsUncompressed(sigversion) && vSolutions[0].size() != 33) {
+            return IsMineResult::INVALID;
+        }
+        if (keystore.HaveKey(keyID)) {
+            ret = std::max(ret, IsMineResult::SPENDABLE);
+        }
+        break;
+    case TX_WITNESS_V0_KEYHASH:
+    {
+        if (sigversion == IsMineSigVersion::WITNESS_V0) {
+            // P2WPKH inside P2WSH is invalid.
+            return IsMineResult::INVALID;
+        }
+        if (sigversion == IsMineSigVersion::TOP && !keystore.HaveCScript(CScriptID(CScript() << OP_0 << vSolutions[0]))) {
+            // We do not support bare witness outputs unless the P2SH version of it would be
+            // acceptable as well. This protects against matching before segwit activates.
+            // This also applies to the P2WSH case.
+            break;
+        }
+        ret = std::max(ret, IsMineInner(keystore, GetScriptForDestination(PKHash(uint160(vSolutions[0]))), IsMineSigVersion::WITNESS_V0));
+        break;
+    }
+    case TX_PUBKEYHASH:
+        keyID = CKeyID(uint160(vSolutions[0]));
+        if (!PermitsUncompressed(sigversion)) {
+            CPubKey pubkey;
+            if (keystore.GetPubKey(keyID, pubkey) && !pubkey.IsCompressed()) {
+                return IsMineResult::INVALID;
+            }
+        }
+        if (keystore.HaveKey(keyID)) {
+            ret = std::max(ret, IsMineResult::SPENDABLE);
+        }
+        break;
+    case TX_SCRIPTHASH:
+    {
+        if (sigversion != IsMineSigVersion::TOP) {
+            // P2SH inside P2WSH or P2SH is invalid.
+            return IsMineResult::INVALID;
+        }
+        CScriptID scriptID = CScriptID(uint160(vSolutions[0]));
+        CScript subscript;
+        if (keystore.GetCScript(scriptID, subscript)) {
+            ret = std::max(ret, IsMineInner(keystore, subscript, IsMineSigVersion::P2SH));
+        }
+        break;
+    }
+    case TX_WITNESS_V0_SCRIPTHASH:
+    {
+        if (sigversion == IsMineSigVersion::WITNESS_V0) {
+            // P2WSH inside P2WSH is invalid.
+            return IsMineResult::INVALID;
+        }
+        if (sigversion == IsMineSigVersion::TOP && !keystore.HaveCScript(CScriptID(CScript() << OP_0 << vSolutions[0]))) {
+            break;
+        }
+        uint160 hash;
+        CRIPEMD160().Write(&vSolutions[0][0], vSolutions[0].size()).Finalize(hash.begin());
+        CScriptID scriptID = CScriptID(hash);
+        CScript subscript;
+        if (keystore.GetCScript(scriptID, subscript)) {
+            ret = std::max(ret, IsMineInner(keystore, subscript, IsMineSigVersion::WITNESS_V0));
+        }
+        break;
+    }
+
+    case TX_MULTISIG:
+    {
+        // Never treat bare multisig outputs as ours (they can still be made watchonly-though)
+        if (sigversion == IsMineSigVersion::TOP) {
+            break;
+        }
+
+        // Only consider transactions "mine" if we own ALL the
+        // keys involved. Multi-signature transactions that are
+        // partially owned (somebody else has a key that can spend
+        // them) enable spend-out-from-under-you attacks, especially
+        // in shared-wallet situations.
+        std::vector<valtype> keys(vSolutions.begin()+1, vSolutions.begin()+vSolutions.size()-1);
+        if (!PermitsUncompressed(sigversion)) {
+            for (size_t i = 0; i < keys.size(); i++) {
+                if (keys[i].size() != 33) {
+                    return IsMineResult::INVALID;
+                }
+            }
+        }
+        if (HaveKeys(keys, keystore)) {
+            ret = std::max(ret, IsMineResult::SPENDABLE);
+        }
+        break;
+    }
+    }
+
+    if (ret == IsMineResult::NO && keystore.HaveWatchOnly(scriptPubKey)) {
+        ret = std::max(ret, IsMineResult::WATCH_ONLY);
+    }
+    return ret;
+}
+
+} // namespace
+
+isminetype IsMine(const CKeyStore& keystore, const CScript& scriptPubKey)
+{
+    switch (IsMineInner(keystore, scriptPubKey, IsMineSigVersion::TOP)) {
+    case IsMineResult::INVALID:
+    case IsMineResult::NO:
+        return ISMINE_NO;
+    case IsMineResult::WATCH_ONLY:
+        return ISMINE_WATCH_ONLY;
+    case IsMineResult::SPENDABLE:
+        return ISMINE_SPENDABLE;
+    }
+    assert(false);
+}
+
+isminetype IsMine(const CKeyStore& keystore, const CTxDestination& dest)
+{
+    CScript script = GetScriptForDestination(dest);
+    return IsMine(keystore, script);
+}