Add new check to detect links to scripts

This new check looks for links in /usr/bin that points to some script in
a non bin path that contains a shebang, and checks if the needed
interpreter is included as a requirement, because in that case rpm won't
be able to inject the requirement by itself.

Fix #1120

rpmlint/checks/FilesCheck.py

@@ -862,6 +862,35 @@ def _check_file_link_relative(self, pkg, fname, pkgfile):
                                          'symlink-contains-up-and-down-segments',
                                          fname, link)
 
+    def _check_file_link_bindir_shebang(self, pkg, fname, pkgfile):
+        basedir = Path(fname).parent
+        linkto = str((basedir / Path(pkgfile.linkto)).resolve())
+        # Link to a file not in the package, so ignore
+        if linkto not in pkg.files:
+            return
+
+        realbin = pkg.files[linkto]
+        # Link to something in bindir is okay
+        if bin_regex.search(realbin.name):
+            return
+        if not stat.S_ISREG(realbin.mode):
+            return
+
+        file_chunk, file_istext = self.peek(realbin.path, pkg)
+        file_interpreter, _file_interpreter_args = script_interpreter(file_chunk)
+        # Not a script with shebang, so ignore
+        if not file_interpreter:
+            return
+
+        # If the shebang interpreter is a dependency, it's okay
+        deps = [x[0] for x in pkg.requires]
+        if file_interpreter in deps:
+            return
+
+        self.output.add_info('W', pkg, 'symlink-to-binary-with-shebang', fname,
+                             f'is a link to a script ({realbin.name}) but missing'
+                             f' requires for {file_interpreter}')
+
     def _check_file_link(self, pkg, fname, pkgfile):
         if not stat.S_ISLNK(pkgfile.mode):
             return
@@ -871,6 +900,7 @@ def _check_file_link(self, pkg, fname, pkgfile):
         self._check_file_link_bindir_exes(pkg, fname)
         self._check_file_link_absolute(pkg, fname, pkgfile)
         self._check_file_link_relative(pkg, fname, pkgfile)
+        self._check_file_link_bindir_shebang(pkg, fname, pkgfile)
 
     def _check_file_dir(self, pkg, fname, pkgfile):
         if not stat.S_ISDIR(pkgfile.mode):

rpmlint/descriptions/FilesCheck.toml

@@ -403,3 +403,9 @@ manual-page-in-subfolder="""
 Manual page should not be placed in a subfolder of a manual section
 directory.
 """
+
+symlink-to-binary-with-shebang="""
+A file in /usr/bin is a link to a script in a different place with a shebang.
+rpm won't be able to inject the needed interpreter as dependency, so it should
+be done manually.
+"""

rpmlint/pkg.py

@@ -450,6 +450,22 @@ def _gather_dep_info(self):
         return (_requires, _prereq, _provides, _conflicts, _obsoletes, _recommends,
                 _suggests, _enhances, _supplements)
 
+    def scriptprog(self, which):
+        """
+        Get the specified script interpreter as a string.
+        Depending on rpm-python version, the string may or may not include
+        interpreter arguments, if any.
+        """
+        if which is None:
+            return ''
+        prog = self[which]
+        if prog is None:
+            prog = ''
+        elif isinstance(prog, (list, tuple)):
+            # http://rpm.org/ticket/847#comment:2
+            prog = ''.join(prog)
+        return prog
+
     def __enter__(self):
         return self
 
@@ -704,22 +720,6 @@ def check_versioned_dep(self, name, version):
                 return True
         return False
 
-    def scriptprog(self, which):
-        """
-        Get the specified script interpreter as a string.
-        Depending on rpm-python version, the string may or may not include
-        interpreter arguments, if any.
-        """
-        if which is None:
-            return ''
-        prog = self[which]
-        if prog is None:
-            prog = ''
-        elif isinstance(prog, (list, tuple)):
-            # http://rpm.org/ticket/847#comment:2
-            prog = ''.join(prog)
-        return prog
-
 
 def get_installed_pkgs(name):
     """Get list of installed package objects by name."""
@@ -796,6 +796,7 @@ def __init__(self, name, is_source=False):
             self.header[getattr(rpm, f'RPMTAG_{tagname}NAME')] = []
             self.header[getattr(rpm, f'RPMTAG_{tagname}FLAGS')] = []
             self.header[getattr(rpm, f'RPMTAG_{tagname}VERSION')] = []
+        self.header[rpm.RPMTAG_FILENAMES] = []
 
     def add_file(self, path, name):
         pkgfile = PkgFile(name)
@@ -816,7 +817,11 @@ def _mock_file(self, path, attrs):
         elif 'content' in attrs:
             content = attrs['content']
 
-        self.add_file_with_content(path, content, metadata=metadata)
+        if 'linkto' in attrs:
+            self.add_symlink_to(path, attrs['linkto'])
+        else:
+            self.add_file_with_content(path, content, metadata=metadata)
+        self.header[rpm.RPMTAG_FILENAMES].append(path)
 
         if 'content-path' in attrs:
             content.close()
@@ -852,6 +857,8 @@ def add_file_with_content(self, name, content, metadata=None, **flags):
         pkg_file = PkgFile(name)
         pkg_file.path = path
         pkg_file.mode = stat.S_IFREG | 0o0644
+        pkg_file.user = 'root'
+        pkg_file.group = 'root'
         self.files[name] = pkg_file
 
         # create files in filesystem
@@ -915,6 +922,8 @@ def add_symlink_to(self, name, target):
         pkg_file = PkgFile(name)
         pkg_file.mode = stat.S_IFLNK
         pkg_file.linkto = target
+        pkg_file.user = 'root'
+        pkg_file.group = 'root'
         self.files[name] = pkg_file
 
     def readlink(self, pkgfile):
@@ -937,3 +946,7 @@ def md5_checksum(self, file_name):
     def cleanup(self):
         if self.dirname:
             self.__tmpdir.cleanup()
+
+    # access the tags like an array
+    def __getitem__(self, key):
+        return self.header.get(key, None)

test/test_files.py

@@ -1,19 +1,33 @@
+import stat
+
 import pytest
 from rpmlint.checks.FilesCheck import FilesCheck
 from rpmlint.checks.FilesCheck import pyc_magic_from_chunk, pyc_mtime_from_chunk
 from rpmlint.checks.FilesCheck import python_bytecode_to_script as pbts
 from rpmlint.checks.FilesCheck import script_interpreter as se
 from rpmlint.filter import Filter
 
-from Testing import CONFIG, get_tested_package, get_tested_path
+from Testing import CONFIG, get_tested_mock_package, get_tested_package, get_tested_path
 
 
 @pytest.fixture(scope='function', autouse=True)
 def filescheck():
     CONFIG.info = True
     output = Filter(CONFIG)
     test = FilesCheck(CONFIG, output)
-    return output, test
+    yield output, test
+
+
+@pytest.fixture
+def output(filescheck):
+    output, _test = filescheck
+    yield output
+
+
+@pytest.fixture
+def test(filescheck):
+    _output, test = filescheck
+    yield test
 
 
 def test_pep3147():
@@ -244,3 +258,45 @@ def test_manual_pages(tmp_path, package, filescheck):
     assert 'W: manpage-not-compressed bz2 /usr/share/man/man1/test.1.zst' in out
     assert 'E: bad-manual-page-folder /usr/share/man/man0p/foo.3.gz expected folder: man3' in out
     assert 'bad-manual-page-folder /usr/share/man/man3/some.3pm.gz' not in out
+
+
+@pytest.mark.parametrize('package', [
+    get_tested_mock_package(
+        files={
+            '/usr/share/package/bin.py': {
+                'content': '#!/usr/bin/python3\nprint("python required")',
+                'metadata': {'mode': 0o755 | stat.S_IFREG},
+            },
+            '/usr/bin/testlink': {
+                'linkto': '../share/package/bin.py',
+            },
+        },
+        header={},
+    ),
+])
+def test_shebang(package, output, test):
+    test.check(package)
+    out = output.print_results(output.results)
+    assert 'W: symlink-to-binary-with-shebang /usr/bin/testlink' in out
+
+
+@pytest.mark.parametrize('package', [
+    get_tested_mock_package(
+        files={
+            '/usr/share/package/bin.py': {
+                'content': '#!/usr/bin/python3\nprint("python required")',
+                'metadata': {'mode': 0o755 | stat.S_IFREG},
+            },
+            '/usr/bin/testlink': {
+                'linkto': '../share/package/bin.py',
+            },
+        },
+        header={
+            'requires': ['/usr/bin/python3'],
+        },
+    ),
+])
+def test_shebang_ok(package, output, test):
+    test.check(package)
+    out = output.print_results(output.results)
+    assert 'W: symlink-to-binary-with-shebang /usr/bin/testlink' not in out