dpkg-source (2.0/3.0 (quilt)): refuse binary files in debian subdir

* scripts/Dpkg/Source/Functions.pm (is_binary): New function
to check if a file is binary by using diff against it.
* scripts/Dpkg/Source/Package/V2.pm (do_build): Check that all files from
the debian sub-directory are non-binary and only allow whitelisted binary
files.
* man/dpkg-source.1: Document this behaviour.

2 files changed, 46 insertions, 3 deletions

diff --git a/scripts/Dpkg/Source/Functions.pm b/scripts/Dpkg/Source/Functions.pm
index 9ad04632f..7c8ca88fe 100644
--- a/scripts/Dpkg/Source/Functions.pm
+++ b/scripts/Dpkg/Source/Functions.pm
@@ -5,10 +5,11 @@ use warnings;
 
 use Exporter;
 our @ISA = qw(Exporter);
-our @EXPORT_OK = qw(erasedir fixperms);
+our @EXPORT_OK = qw(erasedir fixperms is_binary);
 
 use Dpkg::ErrorHandling qw(syserr subprocerr failure);
 use Dpkg::Gettext;
+use Dpkg::IPC;
 
 use POSIX;
 
@@ -49,5 +50,30 @@ sub fixperms {
     subprocerr("chmod -R $modes_set $dir") if $?;
 }
 
+sub is_binary($) {
+    my ($file) = @_;
+
+    # Use diff to check if it's a binary file
+    my $diffgen;
+    my $diff_pid = fork_and_exec(
+        'exec' => [ 'diff', '-u', '--', '/dev/null', $file ],
+        'env' => { LC_ALL => 'C', LANG => 'C', TZ => 'UTC0' },
+        'to_pipe' => \$diffgen
+    );
+    my $result = 0;
+    while (<$diffgen>) {
+        if (m/^binary/i) {
+            $result = 1;
+            last;
+        } elsif (m/^[-+\@ ]/) {
+            $result = 0;
+            last;
+        }
+    }
+    close($diffgen) or syserr("close on diff pipe");
+    wait_child($diff_pid, nocheck => 1, cmdline => "diff -u -- /dev/null $file");
+    return $result;
+}
+
 # vim: set et sw=4 ts=8
 1;
diff --git a/scripts/Dpkg/Source/Package/V2.pm b/scripts/Dpkg/Source/Package/V2.pm
index f6b99da9a..dd39976e2 100644
--- a/scripts/Dpkg/Source/Package/V2.pm
+++ b/scripts/Dpkg/Source/Package/V2.pm
@@ -29,7 +29,7 @@ use Dpkg::Source::Archive;
 use Dpkg::Source::Patch;
 use Dpkg::Version qw(check_version);
 use Dpkg::Exit;
-use Dpkg::Source::Functions qw(erasedir);
+use Dpkg::Source::Functions qw(erasedir is_binary);
 
 use POSIX;
 use File::Basename;
@@ -308,6 +308,23 @@ sub do_build {
             $self->register_error();
         }
     };
+    # Check if the debian directory contains unwanted binary files
+    my $unwanted_binaries = 0;
+    my $check_binary = sub {
+        my $fn = File::Spec->abs2rel($_, $dir);
+        if (-f $_ and is_binary($_)) {
+            if ($include_binaries or $auth_bin_files{$fn}) {
+                push @binary_files, $fn;
+            } else {
+                errormsg(_g("unwanted binary file: %s"), $fn);
+                $unwanted_binaries++;
+            }
+        }
+    };
+    find({ wanted => $check_binary, no_chdir => 1 }, File::Spec->catdir($dir, "debian"));
+    error(_g("detected %d unwanted binary file(s) " .
+        "(add them in debian/source/include-binaries to allow their " .
+        "inclusion)."), $unwanted_binaries) if $unwanted_binaries;
 
     # Create a patch
     my ($difffh, $tmpdiff) = tempfile("$basenamerev.diff.XXXXXX",
@@ -360,7 +377,7 @@ sub do_build {
     $tar->create(options => \@tar_ignore, 'chdir' => $dir);
     $tar->add_directory("debian");
     foreach my $binary (@binary_files) {
-        $tar->add_file($binary);
+        $tar->add_file($binary) unless $binary =~ m{^debian/};
     }
     $tar->finish();