Merge pull request #3025 from sipa/noncanpush

Make signatures with non-canonical data pushes non-standard.

1 files changed, 45 insertions, 0 deletions

diff --git a/src/script.cpp b/src/script.cpp
index 2b66bc73d..83fc91956 100644
--- a/src/script.cpp
+++ b/src/script.cpp
@@ -1863,6 +1863,51 @@ bool CScript::IsPayToScriptHash() const
             this->at(22) == OP_EQUAL);
 }
 
+bool CScript::IsPushOnly() const
+{
+    const_iterator pc = begin();
+    while (pc < end())
+    {
+        opcodetype opcode;
+        if (!GetOp(pc, opcode))
+            return false;
+        // Note that IsPushOnly() *does* consider OP_RESERVED to be a
+        // push-type opcode, however execution of OP_RESERVED fails, so
+        // it's not relevant to P2SH as the scriptSig would fail prior to
+        // the P2SH special validation code being executed.
+        if (opcode > OP_16)
+            return false;
+    }
+    return true;
+}
+
+bool CScript::HasCanonicalPushes() const
+{
+    const_iterator pc = begin();
+    while (pc < end())
+    {
+        opcodetype opcode;
+        std::vector<unsigned char> data;
+        if (!GetOp(pc, opcode, data))
+            return false;
+        if (opcode > OP_16)
+            continue;
+        if (opcode < OP_PUSHDATA1 && opcode > OP_0 && (data.size() == 1 && data[0] <= 16))
+            // Could have used an OP_n code, rather than a 1-byte push.
+            return false;
+        if (opcode == OP_PUSHDATA1 && data.size() < OP_PUSHDATA1)
+            // Could have used a normal n-byte push, rather than OP_PUSHDATA1.
+            return false;
+        if (opcode == OP_PUSHDATA2 && data.size() <= 0xFF)
+            // Could have used an OP_PUSHDATA1.
+            return false;
+        if (opcode == OP_PUSHDATA4 && data.size() <= 0xFFFF)
+            // Could have used an OP_PUSHDATA2.
+            return false;
+    }
+    return true;
+}
+
 class CScriptVisitor : public boost::static_visitor<bool>
 {
 private: