src/fuzz/fuzz-unit-file.c

/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include "conf-parser.h"
#include "fd-util.h"
#include "fileio.h"
#include "fuzz.h"
#include "install.h"
#include "load-fragment.h"
#include "string-util.h"
#include "unit.h"
#include "utf8.h"

int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
        _cleanup_free_ char *out = NULL; /* out should be freed after g */
        size_t out_size;
        _cleanup_fclose_ FILE *f = NULL, *g = NULL;
        _cleanup_free_ char *p = NULL;
        UnitType t;
        _cleanup_(manager_freep) Manager *m = NULL;
        Unit *u;
        const char *name;
        long offset;

        if (size == 0)
                return 0;

        f = fmemopen_unlocked((char*) data, size, "re");
        assert_se(f);

        if (read_line(f, LINE_MAX, &p) < 0)
                return 0;

        t = unit_type_from_string(p);
        if (t < 0)
                return 0;

        if (!unit_vtable[t]->load)
                return 0;

        offset = ftell(f);
        assert_se(offset >= 0);

        for (;;) {
                _cleanup_free_ char *l = NULL;
                const char *ll;

                if (read_line(f, LONG_LINE_MAX, &l) <= 0)
                        break;

                ll = startswith(l, UTF8_BYTE_ORDER_MARK) ?: l;
                ll = ll + strspn(ll, WHITESPACE);

                if (HAS_FEATURE_MEMORY_SANITIZER && startswith(ll, "ListenNetlink")) {
                        /* ListenNetlink causes a false positive in msan,
                         * let's skip this for now. */
                        log_notice("Skipping test because ListenNetlink= is present");
                        return 0;
                }
        }

        assert_se(fseek(f, offset, SEEK_SET) == 0);

        /* We don't want to fill the logs with messages about parse errors.
         * Disable most logging if not running standalone */
        if (!getenv("SYSTEMD_LOG_LEVEL"))
                log_set_max_level(LOG_CRIT);

        assert_se(manager_new(UNIT_FILE_SYSTEM, MANAGER_TEST_RUN_MINIMAL, &m) >= 0);

        name = strjoina("a.", unit_type_to_string(t));
        assert_se(unit_new_for_name(m, unit_vtable[t]->object_size, name, &u) >= 0);

        (void) config_parse(
                        name, name, f,
                        UNIT_VTABLE(u)->sections,
                        config_item_perf_lookup, load_fragment_gperf_lookup,
                        0,
                        u,
                        NULL);

        g = open_memstream_unlocked(&out, &out_size);
        assert_se(g);

        unit_dump(u, g, "");
        manager_dump(m, g, ">>>");

        return 0;
}