tests: add a fuzzer for journald streams

src/fuzz/fuzz-journald-stream.c

@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <linux/sockios.h>
+
+#include "fd-util.h"
+#include "fuzz.h"
+#include "fuzz-journald.h"
+#include "journald-stream.h"
+
+static int stream_fds[2] = { -1, -1 };
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+        Server s;
+        StdoutStream *stream;
+        int v;
+
+        if (size == 0)
+                return 0;
+
+        if (!getenv("SYSTEMD_LOG_LEVEL"))
+                log_set_max_level(LOG_CRIT);
+
+        assert_se(socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0, stream_fds) >= 0);
+        dummy_server_init(&s, NULL, 0);
+        assert_se(stdout_stream_install(&s, stream_fds[0], &stream) >= 0);
+        assert_se(write(stream_fds[1], data, size) == (ssize_t) size);
+        while (ioctl(stream_fds[0], SIOCINQ, &v) == 0 && v)
+                sd_event_run(s.event, (uint64_t) -1);
+        if (s.n_stdout_streams)
+                stdout_stream_destroy(stream);
+        server_done(&s);
+        stream_fds[1] = safe_close(stream_fds[1]);
+
+        return 0;
+}

src/fuzz/fuzz-journald.c

@@ -15,11 +15,15 @@ void dummy_server_init(Server *s, const uint8_t *buffer, size_t size) {
                 .hostname_fd = -1,
                 .notify_fd = -1,
                 .storage = STORAGE_NONE,
+                .line_max = 64,
         };
         assert_se(sd_event_default(&s->event) >= 0);
-        s->buffer = memdup_suffix0(buffer, size);
-        assert_se(s->buffer);
-        s->buffer_size = size + 1;
+
+        if (buffer) {
+                s->buffer = memdup_suffix0(buffer, size);
+                assert_se(s->buffer);
+                s->buffer_size = size + 1;
+        }
 }
 
 void fuzz_journald_processing_function(

src/fuzz/meson.build

@@ -69,6 +69,12 @@ fuzzers += [
           libshared],
          [libselinux]],
 
+        [['src/fuzz/fuzz-journald-stream.c',
+          'src/fuzz/fuzz-journald.c'],
+         [libjournal_core,
+          libshared],
+         [libselinux]],
+
         [['src/fuzz/fuzz-journald-syslog.c',
           'src/fuzz/fuzz-journald.c'],
          [libjournal_core,

src/journal/journald-stream.c

@@ -125,7 +125,7 @@ void stdout_stream_free(StdoutStream *s) {
 
 DEFINE_TRIVIAL_CLEANUP_FUNC(StdoutStream*, stdout_stream_free);
 
-static void stdout_stream_destroy(StdoutStream *s) {
+void stdout_stream_destroy(StdoutStream *s) {
         if (!s)
                 return;
 
@@ -534,7 +534,7 @@ terminate:
         return 0;
 }
 
-static int stdout_stream_install(Server *s, int fd, StdoutStream **ret) {
+int stdout_stream_install(Server *s, int fd, StdoutStream **ret) {
         _cleanup_(stdout_stream_freep) StdoutStream *stream = NULL;
         sd_id128_t id;
         int r;

src/journal/journald-stream.h

@@ -10,4 +10,6 @@ int server_open_stdout_socket(Server *s);
 int server_restore_streams(Server *s, FDSet *fds);
 
 void stdout_stream_free(StdoutStream *s);
+int stdout_stream_install(Server *s, int fd, StdoutStream **ret);
+void stdout_stream_destroy(StdoutStream *s);
 void stdout_stream_send_notify(StdoutStream *s);

test/fuzz/fuzz-journald-stream/basic

@@ -0,0 +1,8 @@
+
+
+6
+1
+0
+0
+0
+hey