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-rw-r--r--src/script/interpreter.cpp55
1 files changed, 44 insertions, 11 deletions
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index cd73b88210..11c909472a 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -157,6 +157,29 @@ bool static CheckPubKeyEncoding(const valtype &vchSig, unsigned int flags) {
return true;
}
+bool static CheckMinimalPush(const valtype& data, opcodetype opcode) {
+ if (data.size() == 0) {
+ // Could have used OP_0.
+ return opcode == OP_0;
+ } else if (data.size() == 1 && data[0] >= 1 && data[0] <= 16) {
+ // Could have used OP_1 .. OP_16.
+ return opcode == OP_1 + (data[0] - 1);
+ } else if (data.size() == 1 && data[0] == 0x81) {
+ // Could have used OP_1NEGATE.
+ return opcode == OP_1NEGATE;
+ } else if (data.size() <= 75) {
+ // Could have used a direct push (opcode indicating number of bytes pushed + those bytes).
+ return opcode == data.size();
+ } else if (data.size() <= 255) {
+ // Could have used OP_PUSHDATA.
+ return opcode == OP_PUSHDATA1;
+ } else if (data.size() <= 65535) {
+ // Could have used OP_PUSHDATA2.
+ return opcode == OP_PUSHDATA2;
+ }
+ return true;
+}
+
bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker)
{
CScript::const_iterator pc = script.begin();
@@ -169,6 +192,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un
if (script.size() > 10000)
return false;
int nOpCount = 0;
+ bool fRequireMinimal = (flags & SCRIPT_VERIFY_MINIMALDATA) != 0;
try
{
@@ -205,9 +229,12 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un
opcode == OP_RSHIFT)
return false; // Disabled opcodes.
- if (fExec && 0 <= opcode && opcode <= OP_PUSHDATA4)
+ if (fExec && 0 <= opcode && opcode <= OP_PUSHDATA4) {
+ if (fRequireMinimal && !CheckMinimalPush(vchPushValue, opcode)) {
+ return false;
+ }
stack.push_back(vchPushValue);
- else if (fExec || (OP_IF <= opcode && opcode <= OP_ENDIF))
+ } else if (fExec || (OP_IF <= opcode && opcode <= OP_ENDIF))
switch (opcode)
{
//
@@ -234,6 +261,8 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un
// ( -- value)
CScriptNum bn((int)opcode - (int)(OP_1 - 1));
stack.push_back(bn.getvch());
+ // The result of these opcodes should always be the minimal way to push the data
+ // they push, so no need for a CheckMinimalPush here.
}
break;
@@ -458,7 +487,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un
// (xn ... x2 x1 x0 n - ... x2 x1 x0 xn)
if (stack.size() < 2)
return false;
- int n = CScriptNum(stacktop(-1)).getint();
+ int n = CScriptNum(stacktop(-1), fRequireMinimal).getint();
popstack(stack);
if (n < 0 || n >= (int)stack.size())
return false;
@@ -557,7 +586,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un
// (in -- out)
if (stack.size() < 1)
return false;
- CScriptNum bn(stacktop(-1));
+ CScriptNum bn(stacktop(-1), fRequireMinimal);
switch (opcode)
{
case OP_1ADD: bn += bnOne; break;
@@ -590,8 +619,8 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un
// (x1 x2 -- out)
if (stack.size() < 2)
return false;
- CScriptNum bn1(stacktop(-2));
- CScriptNum bn2(stacktop(-1));
+ CScriptNum bn1(stacktop(-2), fRequireMinimal);
+ CScriptNum bn2(stacktop(-1), fRequireMinimal);
CScriptNum bn(0);
switch (opcode)
{
@@ -635,9 +664,9 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un
// (x min max -- out)
if (stack.size() < 3)
return false;
- CScriptNum bn1(stacktop(-3));
- CScriptNum bn2(stacktop(-2));
- CScriptNum bn3(stacktop(-1));
+ CScriptNum bn1(stacktop(-3), fRequireMinimal);
+ CScriptNum bn2(stacktop(-2), fRequireMinimal);
+ CScriptNum bn3(stacktop(-1), fRequireMinimal);
bool fValue = (bn2 <= bn1 && bn1 < bn3);
popstack(stack);
popstack(stack);
@@ -727,7 +756,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un
if ((int)stack.size() < i)
return false;
- int nKeysCount = CScriptNum(stacktop(-i)).getint();
+ int nKeysCount = CScriptNum(stacktop(-i), fRequireMinimal).getint();
if (nKeysCount < 0 || nKeysCount > 20)
return false;
nOpCount += nKeysCount;
@@ -738,7 +767,7 @@ bool EvalScript(vector<vector<unsigned char> >& stack, const CScript& script, un
if ((int)stack.size() < i)
return false;
- int nSigsCount = CScriptNum(stacktop(-i)).getint();
+ int nSigsCount = CScriptNum(stacktop(-i), fRequireMinimal).getint();
if (nSigsCount < 0 || nSigsCount > nKeysCount)
return false;
int isig = ++i;
@@ -980,6 +1009,10 @@ bool SignatureChecker::CheckSig(const vector<unsigned char>& vchSigIn, const vec
bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, unsigned int flags, const BaseSignatureChecker& checker)
{
+ if ((flags & SCRIPT_VERIFY_SIGPUSHONLY) != 0 && !scriptSig.IsPushOnly()) {
+ return false;
+ }
+
vector<vector<unsigned char> > stack, stackCopy;
if (!EvalScript(stack, scriptSig, flags, checker))
return false;