Add fuzzer for the bootspec parser

3 files changed, 128 insertions, 0 deletions

diff --git a/src/fuzz/fuzz-bootspec-gen.py b/src/fuzz/fuzz-bootspec-gen.py
new file mode 100644
index 0000000000..aaacbbe7f5
--- /dev/null
+++ b/src/fuzz/fuzz-bootspec-gen.py
@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+"""Generate sample input for fuzz-bootspec"""
+
+import json
+import os
+import sys
+
+config = open(sys.argv[1]).read()
+entries = [(os.path.basename(name), open(name).read())
+           for name in sys.argv[2:]]
+
+data = {
+    'config': config,
+    'entries': entries,
+}
+
+print(json.dumps(data, indent=4))
diff --git a/src/fuzz/fuzz-bootspec.c b/src/fuzz/fuzz-bootspec.c
new file mode 100644
index 0000000000..9907457450
--- /dev/null
+++ b/src/fuzz/fuzz-bootspec.c
@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <string.h>
+
+#include "bootspec.h"
+#include "env-util.h"
+#include "escape.h"
+#include "fuzz.h"
+#include "fd-util.h"
+#include "json.h"
+
+static int json_dispatch_config(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata) {
+        BootConfig *config = ASSERT_PTR(userdata);
+
+        const char *s = json_variant_string(variant);
+        if (!s)
+                return -EINVAL;
+
+        _cleanup_fclose_ FILE *f = NULL;
+        assert_se(f = data_to_file((const uint8_t*) s, strlen(s)));
+
+        (void) boot_loader_read_conf(config, f, "memstream");
+        return 0;
+}
+
+static int json_dispatch_entries(const char *name, JsonVariant *variant, JsonDispatchFlags flags, void *userdata) {
+        BootConfig *config = ASSERT_PTR(userdata);
+        JsonVariant *entry;
+
+        JSON_VARIANT_ARRAY_FOREACH(entry, variant) {
+                if (!json_variant_is_array(entry) ||
+                    json_variant_elements(entry) < 1)
+                        return -EINVAL;
+
+                JsonVariant *v;
+                const char *id = NULL, *raw = NULL;
+                _cleanup_free_ char *data = NULL;
+                ssize_t len = -ENODATA;
+
+                v = json_variant_by_index(entry, 0);
+                if (v)
+                        id = json_variant_string(v);
+                if (!id)
+                        continue;
+
+                v = json_variant_by_index(entry, 1);
+                if (v)
+                        raw = json_variant_string(v);
+                if (raw)
+                        len = cunescape(raw, UNESCAPE_RELAX | UNESCAPE_ACCEPT_NUL, &data);
+                if (len >= 0) {
+                        _cleanup_fclose_ FILE *f = NULL;
+                        assert_se(f = data_to_file((const uint8_t*) data, len));
+
+                        assert_se(boot_config_load_type1(config, f, "/", "/entries", id) != -ENOMEM);
+                }
+        }
+
+        return 0;
+}
+
+static const JsonDispatch data_dispatch[] = {
+        { "config",  JSON_VARIANT_STRING, json_dispatch_config,  0, 0 },
+        { "entries", JSON_VARIANT_ARRAY,  json_dispatch_entries, 0, 0 },
+        {}
+};
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+        _cleanup_free_ const char *datadup = NULL;
+        _cleanup_(boot_config_free) BootConfig config = BOOT_CONFIG_NULL;
+        int r;
+
+        /* Disable most logging if not running standalone */
+        if (!getenv("SYSTEMD_LOG_LEVEL"))
+                log_set_max_level(LOG_CRIT);
+
+        assert_se(datadup = memdup_suffix0(data, size));
+
+        _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
+        r = json_parse(datadup, 0, &v, NULL, NULL);
+        if (r < 0)
+                return 0;
+
+        r = json_dispatch(v, data_dispatch, NULL, 0, &config);
+        if (r < 0)
+                return 0;
+
+        assert_se(boot_config_finalize(&config) >= 0);
+
+        (void) boot_config_select_special_entries(&config);
+
+        _cleanup_close_ int orig_stdout_fd = -1;
+        if (getenv_bool("SYSTEMD_FUZZ_OUTPUT") <= 0) {
+                orig_stdout_fd = fcntl(fileno(stdout), F_DUPFD_CLOEXEC, 3);
+                if (orig_stdout_fd < 0)
+                        log_warning_errno(orig_stdout_fd, "Failed to duplicate fd 1: %m");
+                else
+                        assert_se(freopen("/dev/null", "w", stdout));
+        }
+
+        (void) show_boot_entries(&config, JSON_FORMAT_OFF);
+        (void) show_boot_entries(&config, JSON_FORMAT_PRETTY);
+
+        if (orig_stdout_fd >= 0)
+                assert_se(freopen(FORMAT_PROC_FD_PATH(orig_stdout_fd), "w", stdout));
+
+        return 0;
+}
diff --git a/src/fuzz/meson.build b/src/fuzz/meson.build
index b92fb95e8a..6f36536f1b 100644
--- a/src/fuzz/meson.build
+++ b/src/fuzz/meson.build
@@ -1,6 +1,8 @@
 # SPDX-License-Identifier: LGPL-2.1-or-later
 
 fuzzers += [
+        [files('fuzz-bootspec.c')],
+
         [files('fuzz-bus-label.c')],
 
         [files('fuzz-calendarspec.c')],