Support subkeys properly in Signed-By options

If we limit a file to be signed by a certain key it should usually
accept also being signed by any of this keys subkeys instead of
requiring each subkey to be listed explicitly. If the later is really
wanted we support now also the same syntax as gpg does with appending an
exclamation mark at the end of the fingerprint to force no mapping.

1 files changed, 62 insertions, 51 deletions

diff --git a/apt-pkg/deb/debmetaindex.cc b/apt-pkg/deb/debmetaindex.cc
index 9c7c70784..1afcdf2c0 100644
--- a/apt-pkg/deb/debmetaindex.cc
+++ b/apt-pkg/deb/debmetaindex.cc
@@ -28,6 +28,57 @@
 
 #include <apti18n.h>
 
+static std::string transformFingergrpints(std::string finger) /*{{{*/
+{
+   std::transform(finger.begin(), finger.end(), finger.begin(), ::toupper);
+   if (finger.length() == 40)
+   {
+      if (finger.find_first_not_of("0123456789ABCDEF") == std::string::npos)
+	 return finger;
+   }
+   else if (finger.length() == 41)
+   {
+      auto bang = finger.find_first_not_of("0123456789ABCDEF");
+      if (bang == 40 && finger[bang] == '!')
+	 return finger;
+   }
+   return "";
+}
+									/*}}}*/
+static std::string transformFingergrpintsWithFilenames(std::string const &finger) /*{{{*/
+{
+   // no check for existence as we could be chrooting later or such things
+   if (finger.empty() == false && finger[0] == '/')
+      return finger;
+   return transformFingergrpints(finger);
+}
+									/*}}}*/
+static std::string NormalizeSignedBy(std::string SignedBy, bool const SupportFilenames) /*{{{*/
+{
+   // we could go all fancy and allow short/long/string matches as gpgv/apt-key does,
+   // but fingerprints are harder to fake than the others and this option is set once,
+   // not interactively all the time so easy to type is not really a concern.
+   std::transform(SignedBy.begin(), SignedBy.end(), SignedBy.begin(), [](char const c) {
+      return (isspace(c) == 0) ? c : ',';
+   });
+   auto fingers = VectorizeString(SignedBy, ',');
+   auto const isAnEmptyString = [](std::string const &s) { return s.empty(); };
+   fingers.erase(std::remove_if(fingers.begin(), fingers.end(), isAnEmptyString), fingers.end());
+   if (unlikely(fingers.empty()))
+      return "";
+   if (SupportFilenames)
+      std::transform(fingers.begin(), fingers.end(), fingers.begin(), transformFingergrpintsWithFilenames);
+   else
+      std::transform(fingers.begin(), fingers.end(), fingers.begin(), transformFingergrpints);
+   if (std::any_of(fingers.begin(), fingers.end(), isAnEmptyString))
+      return "";
+   std::stringstream os;
+   std::copy(fingers.begin(), fingers.end() - 1, std::ostream_iterator<std::string>(os, ","));
+   os << *fingers.rbegin();
+   return os.str();
+}
+									/*}}}*/
+
 class APT_HIDDEN debReleaseIndexPrivate					/*{{{*/
 {
    public:
@@ -566,26 +617,9 @@ bool debReleaseIndex::Load(std::string const &Filename, std::string * const Erro
    auto Sign = Section.FindS("Signed-By");
    if (Sign.empty() == false)
    {
-      std::transform(Sign.begin(), Sign.end(), Sign.begin(), [&](char const c) {
-	 return (isspace(c) == 0) ? c : ',';
-      });
-      auto fingers = VectorizeString(Sign, ',');
-      std::transform(fingers.begin(), fingers.end(), fingers.begin(), [&](std::string finger) {
-	 std::transform(finger.begin(), finger.end(), finger.begin(), ::toupper);
-	 if (finger.length() != 40 || finger.find_first_not_of("0123456789ABCDEF") != std::string::npos)
-	 {
-	    if (ErrorText != NULL)
-	       strprintf(*ErrorText, _("Invalid '%s' entry in Release file %s"), "Signed-By", Filename.c_str());
-	    return std::string();
-	 }
-	 return finger;
-      });
-      if (fingers.empty() == false && std::find(fingers.begin(), fingers.end(), "") == fingers.end())
-      {
-	 std::stringstream os;
-	 std::copy(fingers.begin(), fingers.end(), std::ostream_iterator<std::string>(os, ","));
-	 SignedBy = os.str();
-      }
+      SignedBy = NormalizeSignedBy(Sign, false);
+      if (SignedBy.empty() && ErrorText != NULL)
+	 strprintf(*ErrorText, _("Invalid '%s' entry in Release file %s"), "Signed-By", Filename.c_str());
    }
 
    if (AuthPossible)
@@ -737,38 +771,15 @@ bool debReleaseIndex::SetSignedBy(std::string const &pSignedBy)
 {
    if (SignedBy.empty() == true && pSignedBy.empty() == false)
    {
-      if (pSignedBy[0] == '/') // no check for existence as we could be chrooting later or such things
-	 SignedBy = pSignedBy; // absolute path to a keyring file
-      else
-      {
-	 // we could go all fancy and allow short/long/string matches as gpgv/apt-key does,
-	 // but fingerprints are harder to fake than the others and this option is set once,
-	 // not interactively all the time so easy to type is not really a concern.
-	 auto fingers = VectorizeString(pSignedBy, ',');
-	 std::transform(fingers.begin(), fingers.end(), fingers.begin(), [&](std::string finger) {
-	    std::transform(finger.begin(), finger.end(), finger.begin(), ::toupper);
-	    if (finger.length() != 40 || finger.find_first_not_of("0123456789ABCDEF") != std::string::npos)
-	    {
-	       _error->Error(_("Invalid value set for option %s regarding source %s %s (%s)"), "Signed-By", URI.c_str(), Dist.c_str(), "not a fingerprint");
-	       return std::string();
-	    }
-	    return finger;
-	 });
-	 std::stringstream os;
-	 std::copy(fingers.begin(), fingers.end(), std::ostream_iterator<std::string>(os, ","));
-	 SignedBy = os.str();
-      }
-      // Normalize the string: Remove trailing commas
-      while (SignedBy[SignedBy.size() - 1] == ',')
-	 SignedBy.resize(SignedBy.size() - 1);
+      SignedBy = NormalizeSignedBy(pSignedBy, true);
+      if (SignedBy.empty())
+	 _error->Error(_("Invalid value set for option %s regarding source %s %s (%s)"), "Signed-By", URI.c_str(), Dist.c_str(), "not a fingerprint");
    }
-   else {
-      // Only compare normalized strings
-      auto pSignedByView = APT::StringView(pSignedBy);
-      while (pSignedByView[pSignedByView.size() - 1] == ',')
-	 pSignedByView = pSignedByView.substr(0, pSignedByView.size() - 1);
-      if (pSignedByView != SignedBy)
-	 return _error->Error(_("Conflicting values set for option %s regarding source %s %s: %s != %s"), "Signed-By", URI.c_str(), Dist.c_str(), SignedBy.c_str(), pSignedByView.to_string().c_str());
+   else
+   {
+      auto const normalSignedBy = NormalizeSignedBy(pSignedBy, true);
+      if (normalSignedBy != SignedBy)
+	 return _error->Error(_("Conflicting values set for option %s regarding source %s %s: %s != %s"), "Signed-By", URI.c_str(), Dist.c_str(), SignedBy.c_str(), normalSignedBy.c_str());
    }
    return true;
 }