diff --git a/src/resolve/fuzz-resource-record.c b/src/resolve/fuzz-resource-record.c new file mode 100644 index 0000000000..15c465933d --- /dev/null +++ b/src/resolve/fuzz-resource-record.c @@ -0,0 +1,35 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include "fd-util.h" +#include "fuzz.h" +#include "memory-util.h" +#include "resolved-dns-packet.h" + +int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) { + _cleanup_free_ char *out = NULL; /* out should be freed after f */ + size_t out_size; + _cleanup_fclose_ FILE *f = NULL; + _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL, *copy = NULL; + _cleanup_(json_variant_unrefp) JsonVariant *v = NULL; + + if (outside_size_range(size, 0, DNS_PACKET_SIZE_MAX)) + return 0; + + if (dns_resource_record_new_from_raw(&rr, data, size) < 0) + return 0; + + assert_se(copy = dns_resource_record_copy(rr)); + assert_se(dns_resource_record_equal(copy, rr) > 0); + + assert_se(f = open_memstream_unlocked(&out, &out_size)); + (void) fprintf(f, "%s", strna(dns_resource_record_to_string(rr))); + + if (dns_resource_record_to_json(rr, &v) < 0) + return 0; + + (void) json_variant_dump(v, JSON_FORMAT_PRETTY|JSON_FORMAT_COLOR|JSON_FORMAT_SOURCE, f, NULL); + (void) dns_resource_record_to_wire_format(rr, false); + (void) dns_resource_record_to_wire_format(rr, true); + + return 0; +} diff --git a/src/resolve/meson.build b/src/resolve/meson.build index e11aefce7a..cd02c88039 100644 --- a/src/resolve/meson.build +++ b/src/resolve/meson.build @@ -237,6 +237,11 @@ fuzzers += [ libshared], [lib_openssl_or_gcrypt, libm]], + [files('fuzz-resource-record.c'), + [libsystemd_resolve_core, + libshared], + [lib_openssl_or_gcrypt, + libm]], ] systemd_resolved_sources += files('resolved.c') diff --git a/src/resolve/resolved-dns-rr.c b/src/resolve/resolved-dns-rr.c index d47cdbbd8e..f4fa219ab7 100644 --- a/src/resolve/resolved-dns-rr.c +++ b/src/resolve/resolved-dns-rr.c @@ -1137,12 +1137,15 @@ const char *dns_resource_record_to_string(DnsResourceRecord *rr) { break; default: - t = hexmem(rr->generic.data, rr->generic.data_size); - if (!t) - return NULL; - /* Format as documented in RFC 3597, Section 5 */ - r = asprintf(&s, "%s \\# %zu %s", k, rr->generic.data_size, t); + if (rr->generic.data_size == 0) + r = asprintf(&s, "%s \\# 0", k); + else { + t = hexmem(rr->generic.data, rr->generic.data_size); + if (!t) + return NULL; + r = asprintf(&s, "%s \\# %zu %s", k, rr->generic.data_size, t); + } if (r < 0) return NULL; break; diff --git a/test/fuzz/fuzz-resource-record/crash-type-bitmap-to-json b/test/fuzz/fuzz-resource-record/crash-type-bitmap-to-json new file mode 100644 index 0000000000..a7d5b430dd Binary files /dev/null and b/test/fuzz/fuzz-resource-record/crash-type-bitmap-to-json differ diff --git a/test/fuzz/fuzz-resource-record/ub-zero-length-rdata b/test/fuzz/fuzz-resource-record/ub-zero-length-rdata new file mode 100644 index 0000000000..b5301ee20c Binary files /dev/null and b/test/fuzz/fuzz-resource-record/ub-zero-length-rdata differ