[PATCH 2/4] test: spl: Factor out external-data FIT property checks

Turn spl_test_fit_external_oversize() into a parameterized helper
which builds a FIT with external data, overwrites one property of the
image node with a hostile value and checks that spl_load_simple_fit()
fails with the expected error.

This is in preparation for adding tests for the remaining
external-data properties.

No functional change.

Signed-off-by: Anton Ivanov <[email protected]>
---
 test/image/spl_load.c | 48 +++++++++++++++++++++++++++++-------------------
 1 file changed, 29 insertions(+), 19 deletions(-)

diff --git a/test/image/spl_load.c b/test/image/spl_load.c
index c43c977f784..49bfce15c08 100644
--- a/test/image/spl_load.c
+++ b/test/image/spl_load.c
@@ -368,52 +368,62 @@ SPL_IMG_TEST(spl_test_image, FIT_INTERNAL, 0);
 SPL_IMG_TEST(spl_test_image, FIT_EXTERNAL, 0);
 
 /*
- * A FIT image's data-size property is not covered by the configuration
- * signature, so it is untrusted input. load_simple_fit() must reject a
- * data-size larger than the destination rather than overrun it, because the
- * device read happens before the image hash is verified.
+ * Build a FIT with external data, overwrite one property of the image node
+ * with a hostile value and check that loading fails with the expected error.
+ * The external-data properties are excluded from the configuration signature,
+ * so load_simple_fit() must reject values that would wrap its offset/size
+ * arithmetic rather than read from a bogus location.
  */
-static int spl_test_fit_external_oversize(struct unit_test_state *uts)
+static int check_fit_ext_prop(struct unit_test_state *uts, const char *prop,
+			      u32 value, uint bl_len, spl_load_reader h_read,
+			      ulong fit_offset, int expected)
 {
 	size_t img_size, img_data, data_size = SPL_TEST_DATA_SIZE;
 	struct spl_image_info info_write = {
-		.name = "oversize",
+		.name = "ext-prop",
 		.size = data_size,
 	}, info_read = { };
 	struct spl_load_info load;
 	void *img;
 	int node;
 
-	if (!image_supported(FIT_EXTERNAL))
-		return -EAGAIN;
-
 	img_size = create_image(NULL, FIT_EXTERNAL, &info_write, &img_data);
 	ut_assert(img_size);
 	img = calloc(img_size, 1);
 	ut_assertnonnull(img);
 
-	generate_data(img + img_data, data_size, "oversize");
+	generate_data(img + img_data, data_size, "ext-prop");
 	ut_asserteq(img_size, create_image(img, FIT_EXTERNAL, &info_write,
 					   NULL));
 
-	/*
-	 * Inflate data-size far beyond the image buffer and any plausible
-	 * load region. Without a bounds check, load_simple_fit() reads this
-	 * many bytes off the "device" before the hash is checked.
-	 */
 	node = fdt_path_offset(img, FIT_IMAGES_PATH);
 	ut_assert(node >= 0);
 	node = fdt_first_subnode(img, node);
 	ut_assert(node >= 0);
-	ut_assertok(fdt_setprop_inplace_u32(img, node, FIT_DATA_SIZE_PROP,
-					    0x40000000));
+	ut_assertok(fdt_setprop_inplace_u32(img, node, prop, value));
 
-	spl_load_init(&load, spl_test_read, img, 1);
-	ut_asserteq(-EFBIG, spl_load_simple_fit(&info_read, &load, 0, img));
+	spl_load_init(&load, h_read, img, bl_len);
+	ut_asserteq(expected,
+		    spl_load_simple_fit(&info_read, &load, fit_offset, img));
 
 	free(img);
 	return 0;
 }
+
+/*
+ * A FIT image's data-size property is not covered by the configuration
+ * signature, so it is untrusted input. load_simple_fit() must reject a
+ * data-size larger than the destination rather than overrun it, because the
+ * device read happens before the image hash is verified.
+ */
+static int spl_test_fit_external_oversize(struct unit_test_state *uts)
+{
+	if (!image_supported(FIT_EXTERNAL))
+		return -EAGAIN;
+
+	return check_fit_ext_prop(uts, FIT_DATA_SIZE_PROP, 0x40000000, 1,
+				  spl_test_read, 0, -EFBIG);
+}
 SPL_TEST(spl_test_fit_external_oversize, 0);
 
 /*

-- 
2.51.0