You have to do the bounds check before the access.

[apt.git] / methods / connect.cc

diff --git a/methods/connect.cc b/methods/connect.cc
index cb2f83588899b7d76625cd07072d8f6a341d38db..f6fb14769861f6cbdfd55fdd7221e70cf201cf6b 100644 (file)
--- a/methods/connect.cc
+++ b/methods/connect.cc
@@ -63,6 +63,8 @@ void RotateDNS()
                                                                        /*}}}*/
 static bool ConnectionAllowed(char const * const Service, std::string const &Host)/*{{{*/
 {
+   if (unlikely(Host.empty())) // the only legal empty host (RFC2782 '.' target) is detected by caller
+      return false;
    if (APT::String::Endswith(Host, ".onion") && _config->FindB("Acquire::BlockDotOnion", true))
    {
       // TRANSLATOR: %s is e.g. Tor's ".onion" which would likely fail or leak info (RFC7686)
@@ -298,7 +300,13 @@ bool Connect(std::string Host,int Port,const char *Service,
    {
       SrvRecords.clear();
       if (_config->FindB("Acquire::EnableSrvRecords", true) == true)
+      {
          GetSrvRecords(Host, DefPort, SrvRecords);
+        // RFC2782 defines that a lonely '.' target is an abort reason
+        if (SrvRecords.size() == 1 && SrvRecords[0].target.empty())
+           return _error->Error("SRV records for %s indicate that "
+                 "%s service is not available at this domain", Host.c_str(), Service);
+      }
    }
 
    size_t stackSize = 0;