* apt-pkg/indexcopy.cc:

  - Verify that the first line of an InRelease file is a PGP header
    for a signed message. Otherwise a man-in-the-middle can prefix
    a valid InRelease file with his own data! (CVE-2011-1829)

apt-pkg/indexcopy.cc

@@ -664,6 +664,21 @@ bool SigVerify::CopyAndVerify(string CDROM,string Name,vector<string> &SigList,
 bool SigVerify::RunGPGV(std::string const &File, std::string const &FileGPG,
 			int const &statusfd, int fd[2])
 {
+   if (File == FileGPG)
+   {
+      #define SIGMSG "-----BEGIN PGP SIGNED MESSAGE-----\n"
+      char buffer[sizeof(SIGMSG)];
+      FILE* gpg = fopen(File.c_str(), "r");
+      if (gpg == NULL)
+	 return _error->Errno("RunGPGV", _("Could not open file %s"), File.c_str());
+      char const * const test = fgets(buffer, sizeof(buffer), gpg);
+      fclose(gpg);
+      if (test == NULL || strcmp(buffer, SIGMSG) != 0)
+	 return _error->Error(_("File %s doesn't start with a clearsigned message"), File.c_str());
+      #undef SIGMSG
+   }
+
+
    string const gpgvpath = _config->Find("Dir::Bin::gpg", "/usr/bin/gpgv");
    // FIXME: remove support for deprecated APT::GPGV setting
    string const trustedFile = _config->Find("APT::GPGV::TrustedKeyring", _config->FindFile("Dir::Etc::Trusted"));
@@ -688,7 +703,11 @@ bool SigVerify::RunGPGV(std::string const &File, std::string const &FileGPG,
    Args.reserve(30);
 
    if (keyrings.empty() == true)
-      return false;
+   {
+      // TRANSLATOR: %s is the trusted keyring parts directory
+      return _error->Error(_("No keyring installed in %s."),
+			   _config->FindDir("Dir::Etc::TrustedParts").c_str());
+   }
 
    Args.push_back(gpgvpath.c_str());
    Args.push_back("--ignore-time-conflict");

debian/changelog

@@ -16,6 +16,10 @@ apt (0.8.14.2) UNRELEASED; urgency=low
   * Galician translation update (Miguel Anxo Bouzada). Closes: #626505
 
   [ David Kalnischkies ]
+  * apt-pkg/indexcopy.cc:
+    - Verify that the first line of an InRelease file is a PGP header
+      for a signed message. Otherwise a man-in-the-middle can prefix
+      a valid InRelease file with his own data! (CVE-2011-1829)
   * fix a bunch of cppcheck warnings/errors based on a patch by
     Niels Thykier, thanks! (Closes: #622805)
   * apt-pkg/depcache.cc:
@@ -78,7 +82,7 @@ apt (0.8.14.2) UNRELEASED; urgency=low
     - show Acquire::Languages and APT::Architectures settings
       in 'dump' (Closes: 626739)
 
- -- David Kalnischkies <kalnischkies@gmail.com>  Sat, 28 May 2011 10:54:23 +0200
+ -- David Kalnischkies <kalnischkies@gmail.com>  Mon, 06 Jun 2011 21:24:28 +0200
 
 apt (0.8.14.1) unstable; urgency=low
 

methods/gpgv.cc

@@ -65,13 +65,16 @@ string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
       return string("Couldn't spawn new process") + strerror(errno);
    else if (pid == 0)
    {
-      if (SigVerify::RunGPGV(outfile, file, 3, fd) == false)
+      _error->PushToStack();
+      bool const success = SigVerify::RunGPGV(outfile, file, 3, fd);
+      if (success == false)
       {
-	 // TRANSLATOR: %s is the trusted keyring parts directory
-	 ioprintf(ret, _("No keyring installed in %s."),
-		  _config->FindDir("Dir::Etc::TrustedParts").c_str());
-	 return ret.str();
+	 string errmsg;
+	 _error->PopMessage(errmsg);
+	 _error->RevertToStack();
+	 return errmsg;
       }
+      _error->RevertToStack();
       exit(111);
    }
    close(fd[1]);

test/integration/test-ubuntu-bug-784473-InRelease-one-message-only

@@ -0,0 +1,31 @@
+#!/bin/sh
+set -e
+
+TESTDIR=$(readlink -f $(dirname $0))
+. $TESTDIR/framework
+setupenvironment
+configarchitecture 'i386'
+
+insertpackage 'unstable' 'apt' 'i386' '0.8.11'
+
+setupaptarchive
+
+rm -rf rootdir/var/lib/apt/lists
+
+find aptarchive/ -name 'Release.gpg' -delete
+find aptarchive/ -name 'InRelease' -exec cp {} {}.old \;
+
+for RELEASE in $(find aptarchive/ -name 'InRelease'); do
+	(echo 'Origin: Marvin
+Label: Marvin
+Suite: experimental
+Codename: experimental
+MD5Sum:
+ 65fd410587b6978de2277f2912523f09     9360 Packages
+ d27b294ed172a1fa9dd5a53949914c5d     4076 Packages.bz2
+ 2182897e0a2a0c09e760beaae117a015     2023 Packages.diff/Index
+ 1b895931853981ad8204d2439821b999     4144 Packages.gz'; echo; cat ${RELEASE}.old;) > ${RELEASE}
+done
+aptget update -qq > /dev/null 2> starts-with-unsigned.msg
+sed -i 's#File .*InRelease#File InRelease#' starts-with-unsigned.msg
+testfileequal starts-with-unsigned.msg "W: GPG error: file: unstable InRelease: File InRelease doesn't start with a clearsigned message"