[PATCH] tests/qtest/fuzz: Add generic fuzzer for VNC

[Navid Emamdoost <navidem@google.com>]

Add a new generic fuzz target for the QEMU VNC server. This allows the
generic fuzzer to directly exercise the VNC protocol implementation by
connecting to a VNC unix socket.

---

This new target increases code coverage in the VNC subsystem
and related networking and I/O code.
The baseline coverage below was generated by running all existing fuzz
targets with the oss-fuzz corpus. The new target shows significant gains:

----------------------------------------------------------------------------
File                       New Target                Baseline        Change
----------------------------------------------------------------------------
vnc.c                      339/3212 (10.6%)     3/3212 (0.1%)        +336
keymaps.c                  91/184 (49.5%)       0/184 (0.0%)         +91
net-listener.c             76/198 (38.4%)       3/198 (1.5%)         +73
channel-socket.c           73/575 (12.7%)       19/575 (3.3%)        +54
qemu-sockets.c             44/1019 (4.3%)       0/1019 (0.0%)        +44
vnc-jobs.c                 41/219 (18.7%)       0/219 (0.0%)         +41
dns-resolver.c             28/145 (19.3%)       3/145 (2.1%)         +25

Signed-off-by: Navid Emamdoost <navidem@google.com>
---
 tests/qtest/fuzz/generic_fuzz_configs.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tests/qtest/fuzz/generic_fuzz_configs.h b/tests/qtest/fuzz/generic_fuzz_configs.h
index ef0ad95712..2e802ab226 100644
--- a/tests/qtest/fuzz/generic_fuzz_configs.h
+++ b/tests/qtest/fuzz/generic_fuzz_configs.h
@@ -247,6 +247,10 @@ const generic_fuzz_config predefined_configs[] = {
         .args = "-machine q35 -nodefaults "
         "-parallel file:/dev/null",
         .objects = "parallel*",
+    },{
+        .name = "vnc",
+        .args = "-machine q35 -nodefaults -vnc vnc=unix:/tmp/qemu-vnc.sock",
+        .objects = "*",
     }
 };
 
-- 
2.51.0.740.g6adb054d12-goog