Merge #17754: net: Don't allow resolving of std::string with embedded NUL characters. Add tests.

7a046cdc1423963bdcbcf9bb98560af61fa90b37 tests: Avoid using C-style NUL-terminated strings as arguments (practicalswift)
fefb9165f23fe9d10ad092ec31715f906e0d2ee7 tests: Add tests to make sure lookup methods fail on std::string parameters with embedded NUL characters (practicalswift)
9574de86ad703ad942cdd0eca79f48c0d42b102b net: Avoid using C-style NUL-terminated strings as arguments in the netbase interface (practicalswift)

Pull request description:

  Don't allow resolving of `std::string`:s with embedded `NUL` characters.

  Avoid using C-style `NUL`-terminated strings as arguments in the `netbase` interface

  Add tests.

  The only place in where C-style `NUL`-terminated strings are actually needed is here:

  ```diff
  +    if (!ValidAsCString(name)) {
  +        return false;
  +    }
  ...
  -    int nErr = getaddrinfo(pszName, nullptr, &aiHint, &aiRes);
  +    int nErr = getaddrinfo(name.c_str(), nullptr, &aiHint, &aiRes);
       if (nErr)
           return false;
  ```

  Interface changes:

  ```diff
  -bool LookupHost(const char *pszName, std::vector<CNetAddr>& vIP, unsigned int nMaxSolutions, bool fAllowLookup);
  +bool LookupHost(const std::string& name, std::vector<CNetAddr>& vIP, unsigned int nMaxSolutions, bool fAllowLookup);

  -bool LookupHost(const char *pszName, CNetAddr& addr, bool fAllowLookup);
  +bool LookupHost(const std::string& name, CNetAddr& addr, bool fAllowLookup);

  -bool Lookup(const char *pszName, CService& addr, int portDefault, bool fAllowLookup);
  +bool Lookup(const std::string& name, CService& addr, int portDefault, bool fAllowLookup);

  -bool Lookup(const char *pszName, std::vector<CService>& vAddr, int portDefault, bool fAllowLookup, unsigned int nMaxSolutions);
  +bool Lookup(const std::string& name, std::vector<CService>& vAddr, int portDefault, bool fAllowLookup, unsigned int nMaxSolutions);

  -bool LookupSubNet(const char *pszName, CSubNet& subnet);
  +bool LookupSubNet(const std::string& strSubnet, CSubNet& subnet);

  -CService LookupNumeric(const char *pszName, int portDefault = 0);
  +CService LookupNumeric(const std::string& name, int portDefault = 0);

  -bool ConnectThroughProxy(const proxyType &proxy, const std::string& strDest, int port, const SOCKET& hSocketRet, int nTimeout, bool *outProxyConnectionFailed);
  +bool ConnectThroughProxy(const proxyType &proxy, const std::string& strDest, int port, const SOCKET& hSocketRet, int nTimeout, bool& outProxyConnectionFailed);
  ```

  It should be noted that the `ConnectThroughProxy` change (from `bool *outProxyConnectionFailed` to `bool& outProxyConnectionFailed`) has nothing to do with `NUL` handling but I thought it was worth doing when touching this file :)

ACKs for top commit:
  EthanHeilman:
    ACK 7a046cdc1423963bdcbcf9bb98560af61fa90b37
  laanwj:
    ACK 7a046cdc1423963bdcbcf9bb98560af61fa90b37

Tree-SHA512: 66556e290db996917b54091acd591df221f72230f6b9f6b167b9195ee870ebef6e26f4cda2f6f54d00e1c362e1743bf56785d0de7cae854e6bf7d26f6caccaba

1 files changed, 5 insertions, 4 deletions

diff --git a/src/net.cpp b/src/net.cpp
index 75b230d0be..68764bf5cb 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -410,7 +410,7 @@ CNode* CConnman::ConnectNode(CAddress addrConnect, const char *pszDest, bool fCo
             if (hSocket == INVALID_SOCKET) {
                 return nullptr;
             }
-            connected = ConnectThroughProxy(proxy, addrConnect.ToStringIP(), addrConnect.GetPort(), hSocket, nConnectTimeout, &proxyConnectionFailed);
+            connected = ConnectThroughProxy(proxy, addrConnect.ToStringIP(), addrConnect.GetPort(), hSocket, nConnectTimeout, proxyConnectionFailed);
         } else {
             // no proxy needed (none set for target network)
             hSocket = CreateSocket(addrConnect);
@@ -432,7 +432,8 @@ CNode* CConnman::ConnectNode(CAddress addrConnect, const char *pszDest, bool fCo
         std::string host;
         int port = default_port;
         SplitHostPort(std::string(pszDest), port, host);
-        connected = ConnectThroughProxy(proxy, host, port, hSocket, nConnectTimeout, nullptr);
+        bool proxyConnectionFailed;
+        connected = ConnectThroughProxy(proxy, host, port, hSocket, nConnectTimeout, proxyConnectionFailed);
     }
     if (!connected) {
         CloseSocket(hSocket);
@@ -1609,7 +1610,7 @@ void CConnman::ThreadDNSAddressSeed()
                 continue;
             }
             unsigned int nMaxIPs = 256; // Limits number of IPs learned from a DNS seed
-            if (LookupHost(host.c_str(), vIPs, nMaxIPs, true)) {
+            if (LookupHost(host, vIPs, nMaxIPs, true)) {
                 for (const CNetAddr& ip : vIPs) {
                     int nOneDay = 24*3600;
                     CAddress addr = CAddress(CService(ip, Params().GetDefaultPort()), requiredServiceBits);
@@ -1907,7 +1908,7 @@ std::vector<AddedNodeInfo> CConnman::GetAddedNodeInfo()
     }
 
     for (const std::string& strAddNode : lAddresses) {
-        CService service(LookupNumeric(strAddNode.c_str(), Params().GetDefaultPort()));
+        CService service(LookupNumeric(strAddNode, Params().GetDefaultPort()));
         AddedNodeInfo addedNode{strAddNode, CService(), false, false};
         if (service.IsValid()) {
             // strAddNode is an IP:port