tests: add libFuzzer based tests

LibFuzzer is in-process, coverage-guided, evolutionary fuzzing engine.

LibFuzzer is linked with the library under test, and feeds fuzzed inputs
to the library via a specific fuzzing entrypoint (aka "target
function"); the fuzzer then tracks which areas of the code are reached,
and generates mutations on the corpus of input data in order to maximize
the code coverage.

Lets use libFuzzer to fuzz blob and blobmsg parsing for the start.

Ref: https://llvm.org/docs/LibFuzzer.html
Signed-off-by: Petr Štetiar <ynezz@true.cz>

7 files changed, 99 insertions, 0 deletions

diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index bd22057..0cb3342 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -12,3 +12,7 @@ FOREACH(test_case ${test_cases})
   ADD_UNIT_TEST(${test_case})
   ADD_UNIT_TEST_SAN(${test_case})
 ENDFOREACH(test_case)
+
+IF(CMAKE_C_COMPILER_ID STREQUAL "Clang")
+  ADD_SUBDIRECTORY(fuzz)
+ENDIF()
diff --git a/tests/fuzz/CMakeLists.txt b/tests/fuzz/CMakeLists.txt
new file mode 100644
index 0000000..cca74fd
--- /dev/null
+++ b/tests/fuzz/CMakeLists.txt
@@ -0,0 +1,18 @@
+FILE(GLOB test_cases "test-*.c")
+
+MACRO(ADD_FUZZER_TEST name)
+  ADD_EXECUTABLE(${name} ${name}.c)
+  TARGET_COMPILE_OPTIONS(${name} PRIVATE -g -O1 -fno-omit-frame-pointer -fsanitize=fuzzer,address,leak,undefined)
+  TARGET_INCLUDE_DIRECTORIES(${name} PRIVATE ${PROJECT_SOURCE_DIR})
+  TARGET_LINK_OPTIONS(${name} PRIVATE -stdlib=libc++ -fsanitize=fuzzer,address,leak,undefined)
+  TARGET_LINK_LIBRARIES(${name} ubox blobmsg_json json_script ${json})
+  ADD_TEST(
+    NAME ${name}
+    COMMAND ${name} -max_len=256 -timeout=10 -max_total_time=300 ${CMAKE_CURRENT_SOURCE_DIR}/corpus
+  )
+ENDMACRO(ADD_FUZZER_TEST)
+
+FOREACH(test_case ${test_cases})
+  GET_FILENAME_COMPONENT(test_case ${test_case} NAME_WE)
+  ADD_FUZZER_TEST(${test_case})
+ENDFOREACH(test_case)
diff --git a/tests/fuzz/corpus/71520a5c4b5ca73903216857abbad54a8002d44a b/tests/fuzz/corpus/71520a5c4b5ca73903216857abbad54a8002d44a
new file mode 100644
index 0000000..b4e009d
--- /dev/null
+++ b/tests/fuzz/corpus/71520a5c4b5ca73903216857abbad54a8002d44a
diff --git a/tests/fuzz/corpus/c1dfd96eea8cc2b62785275bca38ac261256e278 b/tests/fuzz/corpus/c1dfd96eea8cc2b62785275bca38ac261256e278
new file mode 100644
index 0000000..62f9457
--- /dev/null
+++ b/tests/fuzz/corpus/c1dfd96eea8cc2b62785275bca38ac261256e278
@@ -0,0 +1 @@
+6
\ No newline at end of file
diff --git a/tests/fuzz/corpus/c42ac1c46f1d4e211c735cc7dfad4ff8391110e9 b/tests/fuzz/corpus/c42ac1c46f1d4e211c735cc7dfad4ff8391110e9
new file mode 100644
index 0000000..3d70d85
--- /dev/null
+++ b/tests/fuzz/corpus/c42ac1c46f1d4e211c735cc7dfad4ff8391110e9
diff --git a/tests/fuzz/corpus/valid-blobmsg.bin b/tests/fuzz/corpus/valid-blobmsg.bin
new file mode 100644
index 0000000..2d0c68e
--- /dev/null
+++ b/tests/fuzz/corpus/valid-blobmsg.bin
diff --git a/tests/fuzz/test-fuzz.c b/tests/fuzz/test-fuzz.c
new file mode 100644
index 0000000..7153847
--- /dev/null
+++ b/tests/fuzz/test-fuzz.c
@@ -0,0 +1,76 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <stddef.h>
+
+#include "blob.h"
+#include "blobmsg.h"
+
+static void fuzz_blobmsg_parse(const uint8_t *data, size_t size)
+{
+	enum {
+		FOO_MESSAGE,
+		FOO_LIST,
+		FOO_TESTDATA,
+		__FOO_MAX
+	};
+
+	static const struct blobmsg_policy foo_policy[] = {
+		[FOO_MESSAGE] = {
+			.name = "message",
+			.type = BLOBMSG_TYPE_STRING,
+		},
+		[FOO_LIST] = {
+			.name = "list",
+			.type = BLOBMSG_TYPE_ARRAY,
+		},
+		[FOO_TESTDATA] = {
+			.name = "testdata",
+			.type = BLOBMSG_TYPE_TABLE,
+		},
+	};
+
+	struct blob_attr *tb[__FOO_MAX];
+
+	blobmsg_parse(foo_policy, __FOO_MAX, tb, (uint8_t *)data, size);
+	blobmsg_parse_array(foo_policy, __FOO_MAX, tb, (uint8_t *)data, size);
+}
+
+static void fuzz_blob_parse(const uint8_t *data, size_t size)
+{
+	enum {
+		FOO_ATTR_NESTED,
+		FOO_ATTR_BINARY,
+		FOO_ATTR_STRING,
+		FOO_ATTR_INT8,
+		FOO_ATTR_INT16,
+		FOO_ATTR_INT32,
+		FOO_ATTR_INT64,
+		FOO_ATTR_DOUBLE,
+		__FOO_ATTR_MAX
+	};
+
+
+	static const struct blob_attr_info foo_policy[__FOO_ATTR_MAX] = {
+		[FOO_ATTR_NESTED] = { .type = BLOB_ATTR_NESTED },
+		[FOO_ATTR_BINARY] = { .type = BLOB_ATTR_BINARY },
+		[FOO_ATTR_STRING] = { .type = BLOB_ATTR_STRING },
+		[FOO_ATTR_INT8] = { .type = BLOB_ATTR_INT8 },
+		[FOO_ATTR_INT16] = { .type = BLOB_ATTR_INT16 },
+		[FOO_ATTR_INT32] = { .type = BLOB_ATTR_INT32 },
+		[FOO_ATTR_INT64] = { .type = BLOB_ATTR_INT64 },
+		[FOO_ATTR_DOUBLE] = { .type = BLOB_ATTR_DOUBLE },
+	};
+
+	struct blob_attr *foo[__FOO_ATTR_MAX];
+	struct blob_attr *buf = (struct blob_attr *)data;
+
+	blob_parse(buf, foo, foo_policy, __FOO_ATTR_MAX);
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+	fuzz_blob_parse(data, size);
+	fuzz_blobmsg_parse(data, size);
+
+	return 0;
+}