fuzz: add virtio-9p configurations for fuzzing

virtio-9p devices are often used to expose a virtual-filesystem to the
guest. There have been some bugs reported in this device, such as
CVE-2018-19364, and CVE-2021-20181. We should fuzz this device

This patch adds two virtio-9p configurations:
 * One with the widely used -fsdev local driver. This driver leaks some
   state in the form of files/directories created in the shared dir.
 * One with the synth driver. While it is not used in the real world, this
   driver won't leak leak state between fuzz inputs.

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20210117230924.449676-4-alxndr@bu.edu>

diff --git a/tests/qtest/fuzz/generic_fuzz_configs.h b/tests/qtest/fuzz/generic_fuzz_configs.h
index 51e69c6e42368fa75ebd6e662158a3cc5fa37a9a..5d599765c4bfe06adf30f5dbad5d653f5af9c69d 100644 (file)
--- a/tests/qtest/fuzz/generic_fuzz_configs.h
+++ b/tests/qtest/fuzz/generic_fuzz_configs.h
@@ -19,6 +19,16 @@ typedef struct generic_fuzz_config {
     gchar* (*argfunc)(void); /* Result must be freeable by g_free() */
 } generic_fuzz_config;
 
+static inline gchar *generic_fuzzer_virtio_9p_args(void){
+    char tmpdir[] = "/tmp/qemu-fuzz.XXXXXX";
+    g_assert_nonnull(mkdtemp(tmpdir));
+
+    return g_strdup_printf("-machine q35 -nodefaults "
+    "-device virtio-9p,fsdev=hshare,mount_tag=hshare "
+    "-fsdev local,id=hshare,path=%s,security_model=mapped-xattr,"
+    "writeout=immediate,fmode=0600,dmode=0700", tmpdir);
+}
+
 const generic_fuzz_config predefined_configs[] = {
     {
         .name = "virtio-net-pci-slirp",
@@ -60,6 +70,16 @@ const generic_fuzz_config predefined_configs[] = {
         .name = "virtio-mouse",
         .args = "-machine q35 -nodefaults -device virtio-mouse",
         .objects = "virtio*",
+    },{
+        .name = "virtio-9p",
+        .argfunc = generic_fuzzer_virtio_9p_args,
+        .objects = "virtio*",
+    },{
+        .name = "virtio-9p-synth",
+        .args = "-machine q35 -nodefaults "
+        "-device virtio-9p,fsdev=hshare,mount_tag=hshare "
+        "-fsdev synth,id=hshare",
+        .objects = "virtio*",
     },{
         .name = "e1000",
         .args = "-M q35 -nodefaults "