Merge #12460: Assert CPubKey::ValidLength to the pubkey's header-relevant size

f8c249ab91 Assert CPubKey::ValidLength to the pubkey's header-relevent size (Ben Woosley)

Pull request description:

  A pubkey's length is specific to its type which is indicated by its header value. GetLen returns the header-indicated length, so this change ensures that a key matches its header-indicated length.

  And replace some magic values with their constant equivalents.

Tree-SHA512: b727b39a631babe0932326396fc4d796ade8ec1e37454ff0c709ae9b78ecbd0cfdf59d84089ba8415e6efa7bc180e3cd39a14ddaf0871cbac54b96851e1b7b44

4 files changed, 12 insertions, 7 deletions

diff --git a/src/keystore.cpp b/src/keystore.cpp
index dfdfa5ea9f..e69d518890 100644
--- a/src/keystore.cpp
+++ b/src/keystore.cpp
@@ -127,7 +127,7 @@ static bool ExtractPubKey(const CScript &dest, CPubKey& pubKeyOut)
     CScript::const_iterator pc = dest.begin();
     opcodetype opcode;
     std::vector<unsigned char> vch;
-    if (!dest.GetOp(pc, opcode, vch) || vch.size() < 33 || vch.size() > 65)
+    if (!dest.GetOp(pc, opcode, vch) || !CPubKey::ValidSize(vch))
         return false;
     pubKeyOut = CPubKey(vch);
     if (!pubKeyOut.IsFullyValid())
diff --git a/src/pubkey.h b/src/pubkey.h
index 59bf56395c..9c6c6b085e 100644
--- a/src/pubkey.h
+++ b/src/pubkey.h
@@ -70,6 +70,11 @@ private:
     }
 
 public:
+
+    bool static ValidSize(const std::vector<unsigned char> &vch) {
+      return vch.size() > 0 && GetLen(vch[0]) == vch.size();
+    }
+
     //! Construct an invalid public key.
     CPubKey()
     {
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index 07b2292d46..85dd0a8a81 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -61,17 +61,17 @@ static inline void popstack(std::vector<valtype>& stack)
 }
 
 bool static IsCompressedOrUncompressedPubKey(const valtype &vchPubKey) {
-    if (vchPubKey.size() < 33) {
+    if (vchPubKey.size() < CPubKey::COMPRESSED_PUBLIC_KEY_SIZE) {
         //  Non-canonical public key: too short
         return false;
     }
     if (vchPubKey[0] == 0x04) {
-        if (vchPubKey.size() != 65) {
+        if (vchPubKey.size() != CPubKey::PUBLIC_KEY_SIZE) {
             //  Non-canonical public key: invalid length for uncompressed key
             return false;
         }
     } else if (vchPubKey[0] == 0x02 || vchPubKey[0] == 0x03) {
-        if (vchPubKey.size() != 33) {
+        if (vchPubKey.size() != CPubKey::COMPRESSED_PUBLIC_KEY_SIZE) {
             //  Non-canonical public key: invalid length for compressed key
             return false;
         }
@@ -83,7 +83,7 @@ bool static IsCompressedOrUncompressedPubKey(const valtype &vchPubKey) {
 }
 
 bool static IsCompressedPubKey(const valtype &vchPubKey) {
-    if (vchPubKey.size() != 33) {
+    if (vchPubKey.size() != CPubKey::COMPRESSED_PUBLIC_KEY_SIZE) {
         //  Non-canonical public key: invalid length for compressed key
         return false;
     }
diff --git a/src/script/standard.cpp b/src/script/standard.cpp
index cfb3c58588..0b9053d7fc 100644
--- a/src/script/standard.cpp
+++ b/src/script/standard.cpp
@@ -132,7 +132,7 @@ bool Solver(const CScript& scriptPubKey, txnouttype& typeRet, std::vector<std::v
             // Template matching opcodes:
             if (opcode2 == OP_PUBKEYS)
             {
-                while (vch1.size() >= 33 && vch1.size() <= 65)
+                while (CPubKey::ValidSize(vch1))
                 {
                     vSolutionsRet.push_back(vch1);
                     if (!script1.GetOp(pc1, opcode1, vch1))
@@ -146,7 +146,7 @@ bool Solver(const CScript& scriptPubKey, txnouttype& typeRet, std::vector<std::v
 
             if (opcode2 == OP_PUBKEY)
             {
-                if (vch1.size() < 33 || vch1.size() > 65)
+                if (!CPubKey::ValidSize(vch1))
                     break;
                 vSolutionsRet.push_back(vch1);
             }