Add a Packages-Require-Authorization Release file field

This new field allows a repository to declare that access to
packages requires authorization. The current implementation will
set the pin to -32768 if no authorization has been provided in
the auth.conf(.d) files.

This implementation is suboptimal in two aspects:
(1) A repository should behave more like NotSource repositories
(2) We only have the host name for the repository, we cannot use
    paths yet.

- We can fix those after an ABI break.

The code also adds a check to acquire-item.cc to not use the
specified repository as a download source, mimicking NotSource.

(cherry picked from commit c2b9b0489538fed4770515bd8853a960b13a2618)
LP: #1814727

6 files changed, 63 insertions, 4 deletions

diff --git a/apt-pkg/acquire-item.cc b/apt-pkg/acquire-item.cc
index 83c793093..037dfe656 100644
--- a/apt-pkg/acquire-item.cc
+++ b/apt-pkg/acquire-item.cc
@@ -25,6 +25,7 @@
 #include <apt-pkg/hashes.h>
 #include <apt-pkg/indexfile.h>
 #include <apt-pkg/metaindex.h>
+#include <apt-pkg/netrc.h>
 #include <apt-pkg/pkgcache.h>
 #include <apt-pkg/pkgrecords.h>
 #include <apt-pkg/sourcelist.h>
@@ -3382,6 +3383,7 @@ pkgAcqArchive::pkgAcqArchive(pkgAcquire *const Owner, pkgSourceList *const Sourc
 
    StoreFilename.clear();
    std::set<string> targetComponents, targetCodenames, targetSuites;
+   std::vector<std::unique_ptr<FileFd>> authconfs;
    for (auto Vf = Version.FileList(); Vf.end() == false; ++Vf)
    {
       auto const PkgF = Vf.File();
@@ -3389,6 +3391,8 @@ pkgAcqArchive::pkgAcqArchive(pkgAcquire *const Owner, pkgSourceList *const Sourc
 	 continue;
       if (PkgF.Flagged(pkgCache::Flag::NotSource))
 	 continue;
+      if (PkgF.Flagged(pkgCache::Flag::PackagesRequireAuthorization) && !IsAuthorized(PkgF, authconfs))
+	 continue;
       pkgIndexFile *Index;
       if (Sources->FindIndex(PkgF, Index) == false)
 	 continue;
diff --git a/apt-pkg/contrib/netrc.cc b/apt-pkg/contrib/netrc.cc
index 84b4c0ed8..48114ba3c 100644
--- a/apt-pkg/contrib/netrc.cc
+++ b/apt-pkg/contrib/netrc.cc
@@ -13,6 +13,7 @@
 #include <config.h>
 
 #include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
 #include <apt-pkg/fileutl.h>
 #include <apt-pkg/strutl.h>
 
@@ -149,3 +150,46 @@ void maybe_add_auth(URI &Uri, std::string NetRCFile)
    if (fd.Open(NetRCFile, FileFd::ReadOnly))
       MaybeAddAuth(fd, Uri);
 }
+
+/* Check if we are authorized. */
+bool IsAuthorized(pkgCache::PkgFileIterator const I, std::vector<std::unique_ptr<FileFd>> &authconfs)
+{
+   if (authconfs.empty())
+   {
+      _error->PushToStack();
+      auto const netrc = _config->FindFile("Dir::Etc::netrc");
+      if (not netrc.empty())
+      {
+	 authconfs.emplace_back(new FileFd());
+	 authconfs.back()->Open(netrc, FileFd::ReadOnly);
+      }
+
+      auto const netrcparts = _config->FindDir("Dir::Etc::netrcparts");
+      if (not netrcparts.empty())
+      {
+	 for (auto const &netrc : GetListOfFilesInDir(netrcparts, "conf", true, true))
+	 {
+	    authconfs.emplace_back(new FileFd());
+	    authconfs.back()->Open(netrc, FileFd::ReadOnly);
+	 }
+      }
+      _error->RevertToStack();
+   }
+
+   // FIXME: Use the full base url
+   URI uri(std::string("http://") + I.Site() + "/");
+   for (auto &authconf : authconfs)
+   {
+      if (not authconf->IsOpen())
+	 continue;
+      if (not authconf->Seek(0))
+	 continue;
+
+      MaybeAddAuth(*authconf, uri);
+
+      if (not uri.User.empty() || not uri.Password.empty())
+	 return true;
+   }
+
+   return false;
+}
diff --git a/apt-pkg/contrib/netrc.h b/apt-pkg/contrib/netrc.h
index 981494064..80d95acc1 100644
--- a/apt-pkg/contrib/netrc.h
+++ b/apt-pkg/contrib/netrc.h
@@ -13,9 +13,12 @@
 #ifndef NETRC_H
 #define NETRC_H
 
+#include <memory>
 #include <string>
+#include <vector>
 
 #include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
 
 #ifndef APT_8_CLEANER_HEADERS
 #include <apt-pkg/strutl.h>
@@ -32,4 +35,5 @@ class FileFd;
 APT_DEPRECATED_MSG("Use FileFd-based MaybeAddAuth instead")
 void maybe_add_auth(URI &Uri, std::string NetRCFile);
 bool MaybeAddAuth(FileFd &NetRCFile, URI &Uri);
+bool IsAuthorized(pkgCache::PkgFileIterator const I, std::vector<std::unique_ptr<FileFd>> &authconfs) APT_HIDDEN;
 #endif
diff --git a/apt-pkg/deb/debmetaindex.cc b/apt-pkg/deb/debmetaindex.cc
index 9c7c70784..e0d8d4aae 100644
--- a/apt-pkg/deb/debmetaindex.cc
+++ b/apt-pkg/deb/debmetaindex.cc
@@ -907,6 +907,7 @@ bool debReleaseIndex::Merge(pkgCacheGenerator &Gen,OpProgress * /*Prog*/) const/
    #undef APT_INRELEASE
    Section.FindFlag("NotAutomatic", File->Flags, pkgCache::Flag::NotAutomatic);
    Section.FindFlag("ButAutomaticUpgrades", File->Flags, pkgCache::Flag::ButAutomaticUpgrades);
+   Section.FindFlag("Packages-Require-Authorization", File->Flags, pkgCache::Flag::PackagesRequireAuthorization);
 
    return true;
 }
diff --git a/apt-pkg/pkgcache.h b/apt-pkg/pkgcache.h
index 5c33c7073..787e3995f 100644
--- a/apt-pkg/pkgcache.h
+++ b/apt-pkg/pkgcache.h
@@ -182,9 +182,11 @@ class pkgCache								/*{{{*/
 	 LocalSource=(1<<1), /*!< local sources can't and will not be verified by hashes */
 	 NoPackages=(1<<2), /*!< the file includes no package records itself, but additions like Translations */
       };
-      enum ReleaseFileFlags {
-	 NotAutomatic=(1<<0), /*!< archive has a default pin of 1 */
-	 ButAutomaticUpgrades=(1<<1), /*!< (together with the previous) archive has a default pin of 100 */
+      enum ReleaseFileFlags
+      {
+	 NotAutomatic = (1 << 0),		  /*!< archive has a default pin of 1 */
+	 ButAutomaticUpgrades = (1 << 1),	 /*!< (together with the previous) archive has a default pin of 100 */
+	 PackagesRequireAuthorization = (1 << 2), /*!< (together with the previous) archive has a default pin of 100 */
       };
       enum ProvidesFlags {
 	 MultiArchImplicit=pkgCache::Dep::MultiArchImplicit, /*!< generated internally, not spelled out in the index */
diff --git a/apt-pkg/policy.cc b/apt-pkg/policy.cc
index 6de439d32..7986aa506 100644
--- a/apt-pkg/policy.cc
+++ b/apt-pkg/policy.cc
@@ -18,6 +18,7 @@
 #include <apt-pkg/configuration.h>
 #include <apt-pkg/error.h>
 #include <apt-pkg/fileutl.h>
+#include <apt-pkg/netrc.h>
 #include <apt-pkg/pkgcache.h>
 #include <apt-pkg/policy.h>
 #include <apt-pkg/strutl.h>
@@ -87,7 +88,8 @@ pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(nullptr), VerPins(nullptr),
 // ---------------------------------------------------------------------
 /* */
 bool pkgPolicy::InitDefaults()
-{   
+{
+   std::vector<std::unique_ptr<FileFd>> authconfs;
    // Initialize the priorities based on the status of the package file
    for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); ++I)
    {
@@ -98,6 +100,8 @@ bool pkgPolicy::InitDefaults()
 	 PFPriority[I->ID] = 100;
       else if (I.Flagged(pkgCache::Flag::NotAutomatic))
 	 PFPriority[I->ID] = 1;
+      if (I.Flagged(pkgCache::Flag::PackagesRequireAuthorization) && !IsAuthorized(I, authconfs))
+	 PFPriority[I->ID] = NEVER_PIN;
    }
 
    // Apply the defaults..