Add test for metadata validation

This tests for invalid metadata, missing xa.metadata and mismatched
values in xa.metadata and the real metadata, including the embedded
null leading to the hidden permissions of CVE-2021-43860.

(cherry picked from commit 2c2ce58c54b3e6c62f9c21c15efa0ba22f4bc09b)

tests/Makefile-test-matrix.am.inc

@@ -36,6 +36,7 @@ TEST_MATRIX_DIST= \
 	tests/test-build-update-repo.sh \
 	tests/test-http-utils.sh \
 	tests/test-default-remotes.sh \
+	tests/test-metadata-validation.sh \
 	tests/test-extensions.sh \
 	tests/test-oci.sh \
 	tests/test-override.sh \

tests/Makefile.am.inc

@@ -216,6 +216,7 @@ TEST_MATRIX_SOURCE = \
 	tests/test-repo.sh{{user+system+system-norevokefs}+{{user+system},oldsummary}} \
 	tests/test-sideload.sh{user+system} \
 	tests/test-default-remotes.sh \
+	tests/test-metadata-validation.sh \
 	tests/test-extensions.sh \
 	tests/test-bundle.sh{user+system+system-norevokefs} \
 	tests/test-oci.sh \

tests/test-metadata-validation.sh

@@ -0,0 +1,158 @@
+#!/bin/bash
+#
+# Copyright (C) 2021 Matthew Leeds <mwleeds@protonmail.com>
+#
+# SPDX-License-Identifier: LGPL-2.0-or-later
+
+set -euo pipefail
+
+. $(dirname $0)/libtest.sh
+
+echo "1..7"
+
+setup_repo
+
+COUNTER=1
+
+create_app () {
+    local OPTIONS="$1"
+    local DIR=`mktemp -d`
+
+    mkdir ${DIR}/files
+    echo $COUNTER > ${DIR}/files/counter
+    let COUNTER=COUNTER+1
+
+    local INVALID=""
+    if [[ $OPTIONS =~ "invalid" ]]; then
+        INVALID=invalidkeyfileline
+    fi
+    cat > ${DIR}/metadata <<EOF
+[Application]
+name=org.test.Malicious
+runtime=org.test.Platform/${ARCH}/master
+$INVALID
+
+[Context]
+EOF
+    if [[ $OPTIONS =~ "mismatch" ]]; then
+        echo -e "filesystems=host;" >> ${DIR}/metadata
+    fi
+    if [[ $OPTIONS =~ "hidden" ]]; then
+        echo -ne "\0" >> ${DIR}/metadata
+        echo -e "\nfilesystems=home;" >> ${DIR}/metadata
+    fi
+    local XA_METADATA=--add-metadata-string=xa.metadata="$(head -n6 ${DIR}/metadata)"$'\n'
+    if [[ $OPTIONS =~ "no-xametadata" ]]; then
+        XA_METADATA="--add-metadata-string=xa.nometadata=1"
+    fi
+    ostree commit --repo=repos/test --branch=app/org.test.Malicious/${ARCH}/master ${FL_GPGARGS} "$XA_METADATA" ${DIR}/
+    if [[ $OPTIONS =~ "no-cache-in-summary" ]]; then
+        ostree --repo=repos/test ${FL_GPGARGS} summary -u
+        # force use of legacy summary format
+        rm -rf repos/test/summary.idx repos/test/summaries
+    else
+        update_repo
+    fi
+    rm -rf ${DIR}
+}
+
+cleanup_repo () {
+    ostree refs --repo=repos/test --delete app/org.test.Malicious/${ARCH}/master
+    update_repo
+}
+
+create_app "hidden"
+
+if ${FLATPAK} ${U} install -y test-repo org.test.Malicious 2>install-error-log; then
+    assert_not_reached "Should not be able to install app with hidden permissions"
+fi
+
+assert_file_has_content install-error-log "not matching expected metadata"
+
+assert_not_has_dir $FL_DIR/app/org.test.Malicious/current/active
+
+cleanup_repo
+
+ok "app with hidden permissions can't be installed (CVE-2021-43860)"
+
+create_app no-xametadata
+
+# The install will fail because the metadata in the summary doesn't match the metadata on the commit
+# The missing xa.metadata in the commit got turned into "" in the xa.cache
+if ${FLATPAK} ${U} install -y test-repo org.test.Malicious 2>install-error-log; then
+    assert_not_reached "Should not be able to install app with missing xa.metadata"
+fi
+
+assert_file_has_content install-error-log "not matching expected metadata"
+
+assert_not_has_dir $FL_DIR/app/org.test.Malicious/current/active
+
+cleanup_repo
+
+ok "app with no xa.metadata can't be installed"
+
+create_app "no-xametadata no-cache-in-summary"
+
+# The install will fail because there's no metadata in the summary or on the commit
+if ${FLATPAK} ${U} install -y test-repo org.test.Malicious 2>install-error-log; then
+    assert_not_reached "Should not be able to install app with missing metadata"
+fi
+assert_file_has_content install-error-log "No xa.metadata in local commit"
+
+assert_not_has_dir $FL_DIR/app/org.test.Malicious/current/active
+
+cleanup_repo
+
+ok "app with no xa.metadata and no metadata in summary can't be installed"
+
+create_app "invalid"
+
+if ${FLATPAK} ${U} install -y test-repo org.test.Malicious 2>install-error-log; then
+    assert_not_reached "Should not be able to install app with invalid metadata"
+fi
+assert_file_has_content install-error-log "Metadata for .* is invalid"
+
+assert_not_has_dir $FL_DIR/app/org.test.Malicious/current/active
+
+cleanup_repo
+
+ok "app with invalid metadata (in summary) can't be installed"
+
+create_app "invalid no-cache-in-summary"
+
+if ${FLATPAK} ${U} install -y test-repo org.test.Malicious 2>install-error-log; then
+    assert_not_reached "Should not be able to install app with invalid metadata"
+fi
+assert_file_has_content install-error-log "Metadata for .* is invalid"
+
+assert_not_has_dir $FL_DIR/app/org.test.Malicious/current/active
+
+cleanup_repo
+
+ok "app with invalid metadata (in commit) can't be installed"
+
+create_app "mismatch no-cache-in-summary"
+
+if ${FLATPAK} ${U} install -y test-repo org.test.Malicious 2>install-error-log; then
+    assert_not_reached "Should not be able to install app with non-matching metadata"
+fi
+assert_file_has_content install-error-log "Commit metadata for .* not matching expected metadata"
+
+assert_not_has_dir $FL_DIR/app/org.test.Malicious/current/active
+
+cleanup_repo
+
+ok "app with mismatched metadata (in commit) can't be installed"
+
+create_app "mismatch"
+
+if ${FLATPAK} ${U} install -y test-repo org.test.Malicious 2>install-error-log; then
+    assert_not_reached "Should not be able to install app with non-matching metadata"
+fi
+assert_file_has_content install-error-log "Commit metadata for .* not matching expected metadata"
+
+assert_not_has_dir $FL_DIR/app/org.test.Malicious/current/active
+
+cleanup_repo
+
+ok "app with mismatched metadata (in summary) can't be installed"