test: test that an unprivileged user cannot access the storage

Signed-off-by: Ed Santiago <[email protected]>
Signed-off-by: Giuseppe Scrivano <[email protected]>

test/system/400-unprivileged-access.bats

@@ -0,0 +1,91 @@
+#!/usr/bin/env bats   -*- bats -*-
+#
+# Tests #2730 - regular users are not able to read/write container storage
+#
+
+load helpers
+
+@test "podman container storage is not accessible by unprivileged users" {
+    skip_if_rootless "test meaningless without suid"
+
+    run_podman run --name c_uidmap   --uidmap 0:10000:10000 $IMAGE true
+    run_podman run --name c_uidmap_v --uidmap 0:10000:10000 -v foo:/foo $IMAGE true
+
+    run_podman run --name c_mount $IMAGE \
+               sh -c "echo hi > /myfile;mkdir -p /mydir/mysubdir; chmod 777 /myfile /mydir /mydir/mysubdir"
+
+    run_podman mount c_mount
+    mount_path=$output
+
+    # Do all the work from within a test script. Since we'll be invoking it
+    # as a user, the parent directory must be world-readable.
+    test_script=$PODMAN_TMPDIR/fail-if-writable
+    cat >$test_script <<"EOF"
+#!/bin/sh
+
+path="$1"
+
+die() {
+    echo "#/vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv"  >&2
+    echo "#| FAIL: $*"                                           >&2
+    echo "#\\^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^" >&2
+
+    exit 1
+}
+
+parent=$(dirname "$path")
+if chmod +w $parent; then
+    die "Able to chmod $parent"
+fi
+if chmod +w "$path"; then
+    die "Able to chmod $path"
+fi
+
+if [ -d "$path" ]; then
+    if ls "$path" >/dev/null; then
+        die "Able to run 'ls $path' without error"
+    fi
+    if echo hi >"$path"/test; then
+        die "Able to write to file under $path"
+    fi
+else
+    # Plain file
+    if cat "$path" >/dev/null; then
+        die "Able to read $path"
+    fi
+    if echo hi >"$path"; then
+        die "Able to write to $path"
+    fi
+fi
+
+exit 0
+EOF
+    chmod 755 $PODMAN_TMPDIR $test_script
+
+    # get podman image and container storage directories
+    run_podman info --format '{{.store.GraphRoot}}'
+    GRAPH_ROOT="$output"
+    run_podman info --format '{{.store.RunRoot}}'
+    RUN_ROOT="$output"
+
+    # The main test: find all world-writable files or directories underneath
+    # container storage, run the test script as a nonroot user, and try to
+    # access each path.
+    find $GRAPH_ROOT $RUN_ROOT \! -type l -perm -o+w -print | while read i; do
+        dprint " o+w: $i"
+
+        # use chroot because su fails if uid/gid don't exist or have no shell
+        # For development: test all this by removing the "--userspec x:x"
+        chroot --userspec 1000:1000 / $test_script "$i"
+    done
+
+    # Done. Clean up.
+    rm -f $test_script
+
+    run_podman umount c_mount
+    run_podman rm c_mount
+
+    run_podman rm c_uidmap c_uidmap_v
+}
+
+# vim: filetype=sh