fuzz: add fuzz_dcerpc_parse_binding

We parse a binding and do a few tricks with it, including turning it
into a tower and back.

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

2 files changed, 73 insertions, 0 deletions

diff --git a/lib/fuzzing/fuzz_dcerpc_parse_binding.c b/lib/fuzzing/fuzz_dcerpc_parse_binding.c
new file mode 100644
index 00000000000..5f1c68707ed
--- /dev/null
+++ b/lib/fuzzing/fuzz_dcerpc_parse_binding.c
@@ -0,0 +1,68 @@
+/*
+  Fuzz NMB parse_packet
+  Copyright (C) Catalyst IT 2020
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 3 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#include "includes.h"
+#include "librpc/gen_ndr/ndr_epmapper.h"
+#include "librpc/rpc/dcerpc.h"
+#include "fuzzing/fuzzing.h"
+
+#define MAX_LENGTH (1024 * 10)
+char buf[MAX_LENGTH + 1];
+
+
+int LLVMFuzzerTestOneInput(uint8_t *input, size_t len)
+{
+	TALLOC_CTX *mem_ctx = talloc_new(NULL);
+	struct dcerpc_binding *binding = NULL;
+	struct dcerpc_binding *dup = NULL;
+	struct epm_tower tower;
+	NTSTATUS status;
+	struct GUID guid;
+
+	if (len > MAX_LENGTH) {
+		return 0;
+	}
+	memcpy(buf, input, len);
+	buf[len]  = '\0';
+
+	status = dcerpc_parse_binding(mem_ctx, buf, &binding);
+
+	if (! NT_STATUS_IS_OK(status)) {
+		talloc_free(mem_ctx);
+		return 0;
+	}
+
+	/* If the string parses, we try manipulating it a bit */
+
+	dcerpc_binding_string(mem_ctx, binding);
+	dcerpc_binding_get_abstract_syntax(binding);
+	dup = dcerpc_binding_dup(mem_ctx, binding);
+
+	status = dcerpc_binding_build_tower(mem_ctx,
+					    binding,
+					    &tower);
+	if (NT_STATUS_IS_OK(status)) {
+		status = dcerpc_binding_from_tower(mem_ctx,
+						   &tower,
+						   &dup);
+	}
+
+	guid = dcerpc_binding_get_object(binding);
+
+	talloc_free(mem_ctx);
+	return 0;
+}
diff --git a/lib/fuzzing/wscript_build b/lib/fuzzing/wscript_build
index f8b3886d3da..8bf0db000cf 100644
--- a/lib/fuzzing/wscript_build
+++ b/lib/fuzzing/wscript_build
@@ -72,6 +72,11 @@ bld.SAMBA_BINARY('fuzz_ldb_parse_tree',
                  deps='fuzzing ldb afl-fuzz-main',
                  fuzzer=True)
 
+bld.SAMBA_BINARY('fuzz_dcerpc_parse_binding',
+                 source='fuzz_dcerpc_parse_binding.c',
+                 deps='fuzzing dcerpc afl-fuzz-main',
+                 fuzzer=True)
+
 # The fuzz_type and fuzz_function parameters make the built
 # fuzzer take the same input as ndrdump and so the same that
 # could be sent to the client or server as the stub data.