[Qemu-devel] [PATCH v3 19/22] fuzz: add support for qos-assisted fuzz targets

From: "Oleinik, Alexander" <alxndr@bu.edu>
To: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Cc: "pbonzini@redhat.com" <pbonzini@redhat.com>,
	"bsd@redhat.com" <bsd@redhat.com>,
	"stefanha@redhat.com" <stefanha@redhat.com>,
	"Oleinik, Alexander" <alxndr@bu.edu>
Subject: [Qemu-devel] [PATCH v3 19/22] fuzz: add support for qos-assisted fuzz targets
Date: Wed, 18 Sep 2019 23:19:46 +0000	[thread overview]
Message-ID: <20190918231846.22538-20-alxndr@bu.edu> (raw)
In-Reply-To: <20190918231846.22538-1-alxndr@bu.edu>

Signed-off-by: Alexander Oleinik <alxndr@bu.edu>
---
 tests/fuzz/qos_fuzz.c | 212 ++++++++++++++++++++++++++++++++++++++++++
 tests/fuzz/qos_fuzz.h |  19 ++++
 2 files changed, 231 insertions(+)
 create mode 100644 tests/fuzz/qos_fuzz.c
 create mode 100644 tests/fuzz/qos_fuzz.h

diff --git a/tests/fuzz/qos_fuzz.c b/tests/fuzz/qos_fuzz.c
new file mode 100644
index 0000000000..b08c8b37ba
--- /dev/null
+++ b/tests/fuzz/qos_fuzz.c
@@ -0,0 +1,212 @@
+#include "qemu/osdep.h"
+#include "qemu/units.h"
+#include "qapi/error.h"
+#include "qemu-common.h"
+#include "exec/memory.h"
+#include "exec/address-spaces.h"
+#include "sysemu/sysemu.h"
+#include "qemu/main-loop.h"
+
+#include <wordexp.h>
+
+#include "libqos/malloc.h"
+#include "libqos/qgraph.h"
+#include "libqos/qgraph_internal.h"
+
+#include "fuzz.h"
+#include "qos_fuzz.h"
+#include "tests/libqos/qgraph.h"
+#include "tests/libqos/qos_external.h"
+#include "tests/libqtest.h"
+
+#include "qapi/qapi-commands-machine.h"
+#include "qapi/qapi-commands-qom.h"
+#include "qapi/qmp/qlist.h"
+
+/*
+ * Replaced the qmp commands with direct qmp_marshal calls.
+ * Probably there is a better way to do this
+ */
+static void qos_set_machines_devices_available(void)
+{
+    QDict *req = qdict_new();
+    QObject *response;
+    QDict *args = qdict_new();
+    QList *lst;
+    Error *err = NULL;
+
+    qmp_marshal_query_machines(NULL, &response, &err);
+    assert(!err);
+    lst = qobject_to(QList, response);
+    apply_to_qlist(lst, true);
+
+    qobject_unref(response);
+
+
+    qdict_put_str(req, "execute", "qom-list-types");
+    qdict_put_str(args, "implements", "device");
+    qdict_put_bool(args, "abstract", true);
+    qdict_put_obj(req, "arguments", (QObject *) args);
+
+    qmp_marshal_qom_list_types(args, &response, &err);
+    assert(!err);
+    lst = qobject_to(QList, response);
+    apply_to_qlist(lst, false);
+    qobject_unref(response);
+    qobject_unref(req);
+}
+
+void *fuzz_qos_obj;
+QGuestAllocator *fuzz_qos_alloc;
+
+static char **fuzz_path_vec;
+static char **current_path;
+
+
+void *qos_allocate_objects(QTestState *qts, QGuestAllocator **p_alloc)
+{
+    return allocate_objects(qts, current_path + 1, p_alloc);
+}
+
+
+static void qos_build_main_args()
+{
+    char **path = fuzz_path_vec;
+    QOSGraphNode *test_node;
+    GString *cmd_line = g_string_new(path[0]);
+    void *test_arg;
+
+    /* Before test */
+    current_path = path;
+    test_node = qos_graph_get_node(path[(g_strv_length(path) - 1)]);
+    test_arg = test_node->u.test.arg;
+    if (test_node->u.test.before) {
+        test_arg = test_node->u.test.before(cmd_line, test_arg);
+    }
+    /* Prepend the arguments that we need */
+    g_string_prepend(cmd_line,
+            "qemu-system-i386 -display none -machine accel=qtest -m 128 ");
+    wordexp_t result;
+    wordexp(cmd_line->str, &result, 0);
+    set_fuzz_target_args(result.we_wordc, result.we_wordv);
+
+    g_string_free(cmd_line, true);
+}
+
+/*
+ * This function is largely a copy of qos-test.c:walk_path. Since walk_path
+ * is itself a callback, its a little annoying to add another argument/layer of
+ * indirection
+ */
+static void walk_path(QOSGraphNode *orig_path, int len)
+{
+    QOSGraphNode *path;
+    QOSGraphEdge *edge;
+
+    /* etype set to QEDGE_CONSUMED_BY so that machine can add to the command line */
+    QOSEdgeType etype = QEDGE_CONSUMED_BY;
+
+    /* twice QOS_PATH_MAX_ELEMENT_SIZE since each edge can have its arg */
+    char **path_vec = g_new0(char *, (QOS_PATH_MAX_ELEMENT_SIZE * 2));
+    int path_vec_size = 0;
+
+    char *after_cmd, *before_cmd, *after_device;
+    GString *after_device_str = g_string_new("");
+    char *node_name = orig_path->name, *path_str;
+
+    GString *cmd_line = g_string_new("");
+    GString *cmd_line2 = g_string_new("");
+
+    path = qos_graph_get_node(node_name); /* root */
+    node_name = qos_graph_edge_get_dest(path->path_edge); /* machine name */
+
+    path_vec[path_vec_size++] = node_name;
+    path_vec[path_vec_size++] = qos_get_machine_type(node_name);
+
+    for (;;) {
+        path = qos_graph_get_node(node_name);
+        if (!path->path_edge) {
+            break;
+        }
+
+        node_name = qos_graph_edge_get_dest(path->path_edge);
+
+        /* append node command line + previous edge command line */
+        if (path->command_line && etype == QEDGE_CONSUMED_BY) {
+            g_string_append(cmd_line, path->command_line);
+            g_string_append(cmd_line, after_device_str->str);
+            g_string_truncate(after_device_str, 0);
+        }
+
+        path_vec[path_vec_size++] = qos_graph_edge_get_name(path->path_edge);
+        /* detect if edge has command line args */
+        after_cmd = qos_graph_edge_get_after_cmd_line(path->path_edge);
+        after_device = qos_graph_edge_get_extra_device_opts(path->path_edge);
+        before_cmd = qos_graph_edge_get_before_cmd_line(path->path_edge);
+        edge = qos_graph_get_edge(path->name, node_name);
+        etype = qos_graph_edge_get_type(edge);
+
+        if (before_cmd) {
+            g_string_append(cmd_line, before_cmd);
+        }
+        if (after_cmd) {
+            g_string_append(cmd_line2, after_cmd);
+        }
+        if (after_device) {
+            g_string_append(after_device_str, after_device);
+        }
+    }
+
+    path_vec[path_vec_size++] = NULL;
+    g_string_append(cmd_line, after_device_str->str);
+    g_string_free(after_device_str, true);
+
+    g_string_append(cmd_line, cmd_line2->str);
+    g_string_free(cmd_line2, true);
+
+    /*
+     * here position 0 has <arch>/<machine>, position 1 has <machine>.
+     * The path must not have the <arch>, qtest_add_data_func adds it.
+     */
+    path_str = g_strjoinv("/", path_vec + 1);
+
+    /* Check that this is the test we care about: */
+    char *test_name = strrchr(path_str, '/') + 1;
+    if (strcmp(test_name, get_fuzz_target_name()) == 0) {
+        /*
+         * put arch/machine in position 1 so run_one_test can do its work
+         * and add the command line at position 0.
+         */
+        path_vec[1] = path_vec[0];
+        path_vec[0] = g_string_free(cmd_line, false);
+
+        fuzz_path_vec = path_vec;
+    } else {
+        g_free(path_vec);
+    }
+
+    g_free(path_str);
+}
+
+void fuzz_add_qos_target(const char *name,
+        const char *description,
+        const char *interface,
+        QOSGraphTestOptions *opts,
+        FuzzTarget *fuzz_opts
+        )
+{
+    qos_add_test(name, interface, NULL, opts);
+    fuzz_add_target(name, description, fuzz_opts);
+}
+
+/* Do what is normally done in qos_test.c:main */
+void qos_setup(void){
+    qos_set_machines_devices_available();
+    qos_graph_foreach_test_path(walk_path);
+    qos_build_main_args();
+}
+
+void qos_init_path(QTestState *s)
+{
+    fuzz_qos_obj = qos_allocate_objects(s , &fuzz_qos_alloc);
+}
diff --git a/tests/fuzz/qos_fuzz.h b/tests/fuzz/qos_fuzz.h
new file mode 100644
index 0000000000..4ae775972a
--- /dev/null
+++ b/tests/fuzz/qos_fuzz.h
@@ -0,0 +1,19 @@
+#ifndef _QOS_FUZZ_H_
+#define _QOS_FUZZ_H_
+
+#include "tests/libqos/qgraph.h"
+
+int qos_fuzz(const unsigned char *Data, size_t Size);
+void qos_setup(void);
+
+extern void *fuzz_qos_obj;
+extern QGuestAllocator *fuzz_qos_alloc;
+
+void fuzz_add_qos_target(const char *name,
+        const char *description,
+        const char *interface,
+        QOSGraphTestOptions *opts,
+        FuzzTarget *fuzz_opts);
+
+void qos_init_path(QTestState *);
+#endif
-- 
2.23.0


