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, 2 insertions, 2 deletions

diff --git a/src/httpserver.cpp b/src/httpserver.cpp
index 7179949ea..0e13b8580 100644
--- a/src/httpserver.cpp
+++ b/src/httpserver.cpp
@@ -172,7 +172,7 @@ static bool InitHTTPAllowList()
     rpc_allow_subnets.push_back(CSubNet(localv6));         // always allow IPv6 localhost
     for (const std::string& strAllow : gArgs.GetArgs("-rpcallowip")) {
         CSubNet subnet;
-        LookupSubNet(strAllow.c_str(), subnet);
+        LookupSubNet(strAllow, subnet);
         if (!subnet.IsValid()) {
             uiInterface.ThreadSafeMessageBox(
                 strprintf("Invalid -rpcallowip subnet specification: %s. Valid are a single IP (e.g. 1.2.3.4), a network/netmask (e.g. 1.2.3.4/255.255.255.0) or a network/CIDR (e.g. 1.2.3.4/24).", strAllow),
@@ -324,7 +324,7 @@ static bool HTTPBindAddresses(struct evhttp* http)
         evhttp_bound_socket *bind_handle = evhttp_bind_socket_with_handle(http, i->first.empty() ? nullptr : i->first.c_str(), i->second);
         if (bind_handle) {
             CNetAddr addr;
-            if (i->first.empty() || (LookupHost(i->first.c_str(), addr, false) && addr.IsBindAny())) {
+            if (i->first.empty() || (LookupHost(i->first, addr, false) && addr.IsBindAny())) {
                 LogPrintf("WARNING: the RPC server is not safe to expose to untrusted networks such as the public internet\n");
             }
             boundSockets.push_back(bind_handle);