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 fc7a72ee93a00ef9d3f9a9886d2ba9a7e083145c..f6fb14769861f6cbdfd55fdd7221e70cf201cf6b 100644 (file)
--- a/methods/connect.cc
+++ b/methods/connect.cc
@@ -18,12 +18,13 @@
 #include <apt-pkg/strutl.h>
 #include <apt-pkg/acquire-method.h>
 #include <apt-pkg/configuration.h>
 #include <apt-pkg/strutl.h>
 #include <apt-pkg/acquire-method.h>
 #include <apt-pkg/configuration.h>

+#include <apt-pkg/srvrec.h>

 
 #include <stdio.h>
 #include <errno.h>
 #include <unistd.h>
 #include <sstream>
 
 #include <stdio.h>
 #include <errno.h>
 #include <unistd.h>
 #include <sstream>

-
+#include <string.h>

 #include<set>
 #include<string>
 
 #include<set>
 #include<string>
 


@@ -43,6 +44,8 @@ static int LastPort = 0;
 static struct addrinfo *LastHostAddr = 0;
 static struct addrinfo *LastUsed = 0;
 
 static struct addrinfo *LastHostAddr = 0;
 static struct addrinfo *LastUsed = 0;
 

+static std::vector<SrvRec> SrvRecords;
+

 // Set of IP/hostnames that we timed out before or couldn't resolve
 static std::set<std::string> bad_addr;
 
 // Set of IP/hostnames that we timed out before or couldn't resolve
 static std::set<std::string> bad_addr;
 


@@ -58,10 +61,25 @@ void RotateDNS()
       LastUsed = LastHostAddr;
 }
                                                                        /*}}}*/
       LastUsed = LastHostAddr;
 }
                                                                        /*}}}*/

+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)
+      _error->Error(_("Direct connection to %s domains is blocked by default."), ".onion");
+      if (strcmp(Service, "http") == 0)
+       _error->Error(_("If you meant to use Tor remember to use %s instead of %s."), "tor+http", "http");
+      return false;
+   }
+   return true;
+}
+                                                                       /*}}}*/

 // DoConnect - Attempt a connect operation                             /*{{{*/
 // ---------------------------------------------------------------------
 /* This helper function attempts a connection to a single address. */
 // DoConnect - Attempt a connect operation                             /*{{{*/
 // ---------------------------------------------------------------------
 /* This helper function attempts a connection to a single address. */

-static bool DoConnect(struct addrinfo *Addr,std::string Host,
+static bool DoConnect(struct addrinfo *Addr,std::string const &Host,

                      unsigned long TimeOut,int &Fd,pkgAcqMethod *Owner)
 {
    // Show a status indicator
                      unsigned long TimeOut,int &Fd,pkgAcqMethod *Owner)
 {
    // Show a status indicator


@@ -130,21 +148,19 @@ static bool DoConnect(struct addrinfo *Addr,std::string Host,
    return true;
 }
                                                                        /*}}}*/
    return true;
 }
                                                                        /*}}}*/

-// Connect - Connect to a server                                       /*{{{*/
-// ---------------------------------------------------------------------
-/* Performs a connection to the server */
-bool Connect(std::string Host,int Port,const char *Service,int DefPort,int &Fd,
-            unsigned long TimeOut,pkgAcqMethod *Owner)
+// Connect to a given Hostname                                         /*{{{*/
+static bool ConnectToHostname(std::string const &Host, int const Port,
+      const char * const Service, int DefPort, int &Fd,
+      unsigned long const TimeOut, pkgAcqMethod * const Owner)

 {
 {

-   if (_error->PendingError() == true)
+   if (ConnectionAllowed(Service, Host) == false)

       return false;
       return false;

-

    // Convert the port name/number
    char ServStr[300];
    if (Port != 0)
    // Convert the port name/number
    char ServStr[300];
    if (Port != 0)

-      snprintf(ServStr,sizeof(ServStr),"%u",Port);
+      snprintf(ServStr,sizeof(ServStr),"%i", Port);

    else
    else

-      snprintf(ServStr,sizeof(ServStr),"%s",Service);
+      snprintf(ServStr,sizeof(ServStr),"%s", Service);

    
    /* We used a cached address record.. Yes this is against the spec but
       the way we have setup our rotating dns suggests that this is more
    
    /* We used a cached address record.. Yes this is against the spec but
       the way we have setup our rotating dns suggests that this is more


@@ -165,7 +181,16 @@ bool Connect(std::string Host,int Port,const char *Service,int DefPort,int &Fd,
       struct addrinfo Hints;
       memset(&Hints,0,sizeof(Hints));
       Hints.ai_socktype = SOCK_STREAM;
       struct addrinfo Hints;
       memset(&Hints,0,sizeof(Hints));
       Hints.ai_socktype = SOCK_STREAM;

-      Hints.ai_flags = AI_ADDRCONFIG;
+      Hints.ai_flags = 0;
+#ifdef AI_IDN
+      if (_config->FindB("Acquire::Connect::IDN", true) == true)
+        Hints.ai_flags |= AI_IDN;
+#endif
+      // see getaddrinfo(3): only return address if system has such a address configured
+      // useful if system is ipv4 only, to not get ipv6, but that fails if the system has
+      // no address configured: e.g. offline and trying to connect to localhost.
+      if (_config->FindB("Acquire::Connect::AddrConfig", true) == true)
+        Hints.ai_flags |= AI_ADDRCONFIG;

       Hints.ai_protocol = 0;
       
       if(_config->FindB("Acquire::ForceIPv4", false) == true)
       Hints.ai_protocol = 0;
       
       if(_config->FindB("Acquire::ForceIPv4", false) == true)


@@ -190,7 +215,7 @@ bool Connect(std::string Host,int Port,const char *Service,int DefPort,int &Fd,
            {
               if (DefPort != 0)
               {
            {
               if (DefPort != 0)
               {

-                 snprintf(ServStr,sizeof(ServStr),"%u",DefPort);
+                 snprintf(ServStr, sizeof(ServStr), "%i", DefPort);

                  DefPort = 0;
                  continue;
               }
                  DefPort = 0;
                  continue;
               }


@@ -258,3 +283,60 @@ bool Connect(std::string Host,int Port,const char *Service,int DefPort,int &Fd,
    return _error->Error(_("Unable to connect to %s:%s:"),Host.c_str(),ServStr);
 }
                                                                        /*}}}*/
    return _error->Error(_("Unable to connect to %s:%s:"),Host.c_str(),ServStr);
 }
                                                                        /*}}}*/

+// Connect - Connect to a server                                       /*{{{*/
+// ---------------------------------------------------------------------
+/* Performs a connection to the server (including SRV record lookup) */
+bool Connect(std::string Host,int Port,const char *Service,
+                            int DefPort,int &Fd,
+                            unsigned long TimeOut,pkgAcqMethod *Owner)
+{
+   if (_error->PendingError() == true)
+      return false;
+
+   if (ConnectionAllowed(Service, Host) == false)
+      return false;
+
+   if(LastHost != Host || LastPort != Port)
+   {
+      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;
+   // try to connect in the priority order of the srv records
+   std::string initialHost{std::move(Host)};
+   while(SrvRecords.empty() == false)
+   {
+      _error->PushToStack();
+      ++stackSize;
+      // PopFromSrvRecs will also remove the server
+      Host = PopFromSrvRecs(SrvRecords).target;
+      auto const ret = ConnectToHostname(Host, Port, Service, DefPort, Fd, TimeOut, Owner);
+      if (ret)
+      {
+        while(stackSize--)
+           _error->RevertToStack();
+         return true;
+      }
+   }
+   Host = std::move(initialHost);
+
+   // we have no (good) SrvRecords for this host, connect right away
+   _error->PushToStack();
+   ++stackSize;
+   auto const ret = ConnectToHostname(Host, Port, Service, DefPort, Fd,
+        TimeOut, Owner);
+   while(stackSize--)
+      if (ret)
+        _error->RevertToStack();
+      else
+        _error->MergeWithStack();
+   return ret;
+}