From aec8ec45a496ad4b034bbc5cadf00f205c8e0fd3 Mon Sep 17 00:00:00 2001
From: Cave Spectre <crypto@pontificatingnobody.com>
Date: Sat, 13 Jul 2019 17:39:58 -0400
Subject: [PATCH] [RPC] require valid URL scheme on budget commands

---
 src/rpc/budget.cpp       |  5 +++--
 src/utilstrencodings.cpp | 40 ++++++++++++++++++++++++++++++++++++++++
 src/utilstrencodings.h   |  1 +
 3 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/src/rpc/budget.cpp b/src/rpc/budget.cpp
index e05b61ff9b272e..27d60764e7332f 100644
--- a/src/rpc/budget.cpp
+++ b/src/rpc/budget.cpp
@@ -56,8 +56,9 @@ void checkBudgetInputs(const UniValue& params, std::string &strProposalName, std
         throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid proposal name, limit of 20 characters.");
 
     strURL = SanitizeString(params[1].get_str());
-    if (strURL.size() > 64)
-        throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid url, limit of 64 characters.");
+    std::string strErr;
+    if (!validateURL(strURL, strErr))
+        throw JSONRPCError(RPC_INVALID_PARAMETER, strErr);
 
     nPaymentCount = params[2].get_int();
     if (nPaymentCount < 1)
diff --git a/src/utilstrencodings.cpp b/src/utilstrencodings.cpp
index 16fd87aa4f3d5b..41ee86c954a668 100644
--- a/src/utilstrencodings.cpp
+++ b/src/utilstrencodings.cpp
@@ -39,6 +39,46 @@ std::string SanitizeString(const std::string& str, int rule)
     return strResult;
 }
 
+/*
+** bool validateURL(std::string, int [optional, defaulted to 64])
+**
+** Input:
+**   strURL: A std::string URL to be be processed for validity.
+**   strErr: A std::string to be filled with any error messages.
+**   maxSize: An int to define the maximum size the URL can be;
+**            Optional, defaulting to 64.
+**
+** Return:
+**    boolean true|false result if the validation passes.
+**    strRrror: Filled with any error messages.
+*/
+bool validateURL(std::string strURL, std::string& strErr, unsigned int maxSize) {
+
+    // Check URL size
+    if (strURL.size() > maxSize) {
+        strErr = strprintf("Invalid URL: %d exceeds limit of %d characters.", strURL.size(), maxSize);
+        return false;
+    }
+
+    std::vector<std::string> reqPre;
+
+    // Required initial strings; URL must contain one
+    reqPre.push_back("http://");
+    reqPre.push_back("https://");
+
+    // check fronts
+    bool found = false;
+    for (int i=0; i < reqPre.size() && !found; i++) {
+        if (strURL.find(reqPre[i]) == 0) found = true;
+    }
+    if ((!found) && (reqPre.size() > 0)) {
+        strErr = "Invalid URL, check scheme (e.g. https://)";
+        return false;
+    }
+
+    return true;
+}
+
 const signed char p_util_hexdigit[256] =
     {
         -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
diff --git a/src/utilstrencodings.h b/src/utilstrencodings.h
index 97c3bfd91fbc93..5f7dfbc120ee80 100644
--- a/src/utilstrencodings.h
+++ b/src/utilstrencodings.h
@@ -40,6 +40,7 @@ enum SafeChars
 * @return           A new string without unsafe chars
 */
 std::string SanitizeString(const std::string& str, int rule = SAFE_CHARS_DEFAULT);
+bool validateURL(std::string strURL, std::string& strErr, unsigned int maxSize = 64);
 std::vector<unsigned char> ParseHex(const char* psz);
 std::vector<unsigned char> ParseHex(const std::string& str);
 signed char HexDigit(char c);