[PATCH 3/3] mkimage: fit: don't cipher ciphered data

[patrick.oppenlander at gmail.com <patrick.oppenlander@gmail.com>]

From: Patrick Oppenlander <patrick.oppenlander@gmail.com>

Previously, mkimage -F could be run multiple times causing already
ciphered image data to be ciphered again.

Signed-off-by: Patrick Oppenlander <patrick.oppenlander@gmail.com>
---
 tools/image-host.c | 47 +++++++++++++++++++++++++++++++---------------
 1 file changed, 32 insertions(+), 15 deletions(-)

diff --git a/tools/image-host.c b/tools/image-host.c
index 87ef79ef53..12de9b5ec0 100644
--- a/tools/image-host.c
+++ b/tools/image-host.c
@@ -397,33 +397,43 @@ int fit_image_write_cipher(void *fit, int image_noffset, int noffset,
 			   const void *data, size_t size,
 			   unsigned char *data_ciphered, int data_ciphered_len)
 {
-	int ret = -1;
+	/*
+	 * fit_image_cipher_data() uses the presence of the data-size-unciphered
+	 * property as a sentinel to detect whether the data for this image is
+	 * already encrypted. This is important as:
+	 * - 'mkimage -F' can be run multiple times on a FIT image
+	 * - This function is in a retry loop to handle ENOSPC
+	 */
 
-	/* add non ciphered data size */
+	int ret;
+
+	/* Add unciphered data size */
 	ret = fdt_setprop_u32(fit, image_noffset, "data-size-unciphered", size);
-	if (ret == -FDT_ERR_NOSPACE) {
-		ret = -ENOSPC;
-		goto out;
-	}
+	if (ret == -FDT_ERR_NOSPACE)
+		return -ENOSPC;
 	if (ret) {
 		printf("Can't add unciphered data size (err = %d)\n", ret);
-		goto out;
+		return -EIO;
 	}
 
-	/* Add ciphered data */
+	/* Replace contents of data property with data_ciphered */
 	ret = fdt_setprop(fit, image_noffset, FIT_DATA_PROP,
 			  data_ciphered, data_ciphered_len);
 	if (ret == -FDT_ERR_NOSPACE) {
-		ret = -ENOSPC;
-		goto out;
+		/* Remove data-size-unciphered; data is not ciphered */
+		ret = fdt_delprop(fit, image_noffset, "data-size-unciphered");
+		if (ret) {
+			printf("Can't remove unciphered data size (err = %d)\n", ret);
+			return -EIO;
+		}
+		return -ENOSPC;
 	}
 	if (ret) {
-		printf("Can't add ciphered data (err = %d)\n", ret);
-		goto out;
+		printf("Can't replace data with ciphered data (err = %d)\n", ret);
+		return -EIO;
 	}
 
- out:
-	return ret;
+	return 0;
 }
 
 static int
@@ -482,7 +492,7 @@ int fit_image_cipher_data(const char *keydir, void *keydest,
 	const char *image_name;
 	const void *data;
 	size_t size;
-	int cipher_node_offset;
+	int cipher_node_offset, len;
 
 	/* Get image name */
 	image_name = fit_get_name(fit, image_noffset, NULL);
@@ -497,6 +507,13 @@ int fit_image_cipher_data(const char *keydir, void *keydest,
 		return -1;
 	}
 
+	/* Don't cipher ciphered data */
+	if (fdt_getprop(fit, image_noffset, "data-size-unciphered", &len))
+		return 0;
+	if (len != -FDT_ERR_NOTFOUND) {
+		printf("Failure testing for data-size-unciphered\n");
+		return -1;
+	}
 
 	/* Process cipher node if present */
 	cipher_node_offset = fdt_subnode_offset(fit, image_noffset, "cipher");
-- 
2.27.0