[cifuzz] Handle upgrade to Ubuntu 20.04 (#6249)

Handle upgrade to Ubuntu 20.04

1. Don't do any special handling for MSAN anymore. It isn't needed.
2. Don't do any special handling for msan-libs-builder it doesn't
exist anymore.

Related: #6180

infra/cifuzz/build_fuzzers.py

@@ -85,11 +85,6 @@ def build_fuzzers(self):
       docker_args.extend(
           _get_docker_build_fuzzers_args_not_container(self.host_repo_path))
 
-    if self.config.sanitizer == 'memory':
-      docker_args.extend(
-          _get_docker_build_fuzzers_args_msan(self.workspace.work))
-      self.handle_msan_prebuild(docker_container)
-
     docker_args.extend([
         docker.get_project_image_name(self.config.oss_fuzz_project_name),
         '/bin/bash',
@@ -107,8 +102,6 @@ def build_fuzzers(self):
       logging.error('Building fuzzers failed.')
       return False
 
-    if self.config.sanitizer == 'memory':
-      self.handle_msan_postbuild(docker_container)
     return True
 
   def upload_build(self):
@@ -119,23 +112,6 @@ def upload_build(self):
 
     return True
 
-  def handle_msan_postbuild(self, container):
-    """Post-build step for MSAN builds. Patches the build to use MSAN
-    libraries."""
-    helper.docker_run([
-        '--volumes-from', container, '-e', f'WORK={self.workspace.work}',
-        docker.MSAN_LIBS_BUILDER_TAG, 'patch_build.py', '/out'
-    ])
-
-  def handle_msan_prebuild(self, container):
-    """Pre-build step for MSAN builds. Copies MSAN libs to |msan_libs_dir| and
-    returns docker arguments to use that directory for MSAN libs."""
-    logging.info('Copying MSAN libs.')
-    helper.docker_run([
-        '--volumes-from', container, docker.MSAN_LIBS_BUILDER_TAG, 'bash', '-c',
-        f'cp -r /msan {self.workspace.work}'
-    ])
-
   def build(self):
     """Builds the image, checkouts the source (if needed), builds the fuzzers
     and then removes the unaffectted fuzzers. Returns True on success."""
@@ -226,11 +202,3 @@ def _get_docker_build_fuzzers_args_not_container(host_repo_path):
   |host_repo_path| when the host of the OSS-Fuzz builder container is not
   another container."""
   return ['-v', f'{host_repo_path}:{host_repo_path}']
-
-
-def _get_docker_build_fuzzers_args_msan(work_dir):
-  """Returns arguments to the docker build command that are needed to use
-  MSAN."""
-  # TODO(metzman): MSAN is broken, fix.
-  msan_libs_path = os.path.join(work_dir, 'msan')
-  return ['-e', f'MSAN_LIBS_PATH={msan_libs_path}']

infra/cifuzz/build_fuzzers_test.py

@@ -369,16 +369,5 @@ def test_get_docker_build_fuzzers_args_no_container(self):
     self.assertEqual(result, expected_result)
 
 
-class GetDockerBuildFuzzersArgsMsanTest(unittest.TestCase):
-  """Tests that _get_docker_build_fuzzers_args_msan works as intended."""
-
-  def test_get_docker_build_fuzzers_args_msan(self):
-    """Tests that _get_docker_build_fuzzers_args_msan works as intended."""
-    work_dir = '/work_dir'
-    result = build_fuzzers._get_docker_build_fuzzers_args_msan(work_dir)
-    expected_result = ['-e', 'MSAN_LIBS_PATH=/work_dir/msan']
-    self.assertEqual(result, expected_result)
-
-
 if __name__ == '__main__':
   unittest.main()

infra/cifuzz/docker.py

@@ -23,7 +23,6 @@
 import utils
 
 BASE_BUILDER_TAG = 'gcr.io/oss-fuzz-base/base-builder'
-MSAN_LIBS_BUILDER_TAG = 'gcr.io/oss-fuzz-base/msan-libs-builder'
 PROJECT_TAG_PREFIX = 'gcr.io/oss-fuzz/'
 
 # Default fuzz configuration.

infra/cifuzz/run_fuzzers_entrypoint.py

@@ -36,7 +36,6 @@ def delete_unneeded_docker_images(config):
   project_image = docker.get_project_image_name(config.oss_fuzz_project_name)
   images = [
       project_image,
-      docker.MSAN_LIBS_BUILDER_TAG,
   ]
   docker.delete_images(images)