gluten: check limits

Add bounds checking:
  - if offset is larger then the maximum per offset type
  - if memcpy is reading/writing inside gluten

3 files changed, 130 insertions, 0 deletions

diff --git a/tests/unit/Makefile b/tests/unit/Makefile
index 202e198..966ae7d 100644
--- a/tests/unit/Makefile
+++ b/tests/unit/Makefile
@@ -23,6 +23,10 @@ HEADERS_OP := $(COMMON_DIR)/gluten.h  $(OP_DIR)/operations.h \
 		   $(COMMON_DIR)/common.h testutil.h $(COMMON_DIR)/util.h
 SRCS_OP := $(COMMON_DIR)/common.c $(OP_DIR)/operations.c util.c $(COMMON_DIR)/util.c
 
+HEADERS_ERROR := $(COMMON_DIR)/gluten.h  $(OP_DIR)/operations.h \
+		   $(COMMON_DIR)/common.h testutil.h $(COMMON_DIR)/util.h
+SRCS_ERROR := $(COMMON_DIR)/common.c $(OP_DIR)/operations.c util.c $(COMMON_DIR)/util.c
+
 TARGET := $(shell $(CC) -dumpmachine)
 TARGET_ARCH := $(shell echo $(TARGET) | cut -f1 -d- | tr [A-Z] [a-z])
 TARGET_ARCH := $(shell echo $(TARGET_ARCH) | sed 's/powerpc/ppc/')
@@ -67,5 +71,11 @@ build-operations: test_operations.c $(SRCS_OP) $(HEADERS_OP)
 test-operations: build-operations
 	./operations
 
+build-error-checks: test_errors.c $(SRCS_ERROR) $(HEADERS_ERROR)
+	$(CC) $(CFLAGS) -o error_checks $(SRCS_ERROR) \
+		test_errors.c
+
+test-error-checks: build-error-checks
+	./error_checks
 clean:
 	rm -f operations  op-call filter filter-build
diff --git a/tests/unit/test_errors.c b/tests/unit/test_errors.c
new file mode 100644
index 0000000..d00d42e
--- /dev/null
+++ b/tests/unit/test_errors.c
@@ -0,0 +1,118 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/syscall.h>
+
+#include <check.h>
+
+#include "operations.h"
+#include "common/common.h"
+#include "common/gluten.h"
+#include "testutil.h"
+
+static void setup_error_check()
+{
+	at = mmap(NULL, sizeof(struct args_target), PROT_READ | PROT_WRITE,
+		  MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+	at->check_fd = false;
+	at->nr = __NR_getpid;
+	at->install_filter = install_notification_filter;
+	setup();
+}
+
+struct gluten_offset test_max_size_data[] = {
+	{ OFFSET_DATA, DATA_SIZE },
+	{ OFFSET_RO_DATA, RO_DATA_SIZE },
+	{ OFFSET_SECCOMP_DATA, 6 },
+	{ OFFSET_INSTRUCTION, INST_SIZE },
+};
+
+START_TEST(test_bound_check)
+{
+	struct op ops[] = {
+		{ OP_RETURN, { { 0 } } },
+	};
+	ops[0].op.ret.val.offset = test_max_size_data[_i].offset;
+	ops[0].op.ret.val.type = test_max_size_data[_i].type;
+
+	eval(&gluten, ops, &req, notifyfd);
+}
+
+START_TEST(test_write_op_return)
+{
+	struct op ops[] = {
+		{ OP_CALL,
+		  { .call = { .nr = __NR_getpid,
+			      .has_ret = true,
+			      .ret = { OFFSET_DATA, DATA_SIZE - 1 } } } },
+	};
+
+	eval(&gluten, ops, &req, notifyfd);
+}
+
+START_TEST(test_write_op_load)
+{
+	char a[30];
+	struct op ops[] = {
+		{ OP_LOAD,
+		  { .load = { { OFFSET_SECCOMP_DATA, 1 },
+			      { OFFSET_DATA, DATA_SIZE - 1 },
+			      sizeof(a) } } },
+	};
+
+	eval(&gluten, ops, &req, notifyfd);
+}
+
+START_TEST(test_read_op_return)
+{
+	struct op ops[] = {
+		{ OP_RETURN, { { 0 } } },
+	};
+	ops[0].op.ret.val.offset = test_max_size_data[_i].offset - 1;
+	ops[0].op.ret.val.type = test_max_size_data[_i].type;
+
+	eval(&gluten, ops, &req, notifyfd);
+}
+
+Suite *error_suite(void)
+{
+	Suite *s;
+	TCase *bounds, *gwrite, *gread;
+
+	s = suite_create("Error handling");
+
+	bounds = tcase_create("bound checks");
+	tcase_add_loop_exit_test(bounds, test_bound_check, EXIT_FAILURE, 0,
+				 sizeof(test_max_size_data) /
+					 sizeof(test_max_size_data[0]));
+	suite_add_tcase(s, bounds);
+
+	gwrite = tcase_create("write gluten");
+	tcase_add_checked_fixture(gwrite, setup_error_check, teardown);
+	tcase_add_exit_test(gwrite, test_write_op_return, EXIT_FAILURE);
+	tcase_add_exit_test(gwrite, test_write_op_load, EXIT_FAILURE);
+	suite_add_tcase(s, gwrite);
+
+	gread = tcase_create("read gluten");
+	tcase_add_loop_exit_test(gread, test_read_op_return, EXIT_FAILURE, 0,
+				 sizeof(test_max_size_data) /
+					 sizeof(test_max_size_data[0]));
+	suite_add_tcase(s, gread);
+
+	return s;
+}
+
+int main(void)
+{
+	int no_failed = 0;
+	Suite *s;
+	SRunner *runner;
+
+	s = error_suite();
+	runner = srunner_create(s);
+
+	srunner_run_all(runner, CK_VERBOSE);
+	no_failed = srunner_ntests_failed(runner);
+	srunner_free(runner);
+	return (no_failed == 0) ? EXIT_SUCCESS : EXIT_FAILURE;
+}
diff --git a/tests/unit/testutil.h b/tests/unit/testutil.h
index 45fe08f..ec881c7 100644
--- a/tests/unit/testutil.h
+++ b/tests/unit/testutil.h
@@ -20,6 +20,8 @@
 static inline void *test_gluten_write_ptr(struct gluten *g,
 					  const struct gluten_offset x)
 {
+	ck_assert_msg(is_offset_valid(x), "offset out of bounds");
+
 	switch (x.type) {
 	case OFFSET_DATA:
 		return (char *)g->data + x.offset;