[U-Boot,v2,39/45] mkimage: Add -r option to specify keys that must be verified

Message ID 1363650725-30459-40-git-send-email-sjg@chromium.org
State Deferred
Delegated to: Tom Rini
Headers show

Commit Message

Simon Glass March 18, 2013, 11:51 p.m.
Normally, multiple public keys can be provided and U-Boot is not
required to use all of them for verification. This is because some
images may not be signed, or may be optionally signed.

But we still need a mechanism to determine when a key must be used.
This feature cannot be implemented in the FIT itself, since anyone
could change it to mark a key as optional. The requirement for
key verification must go in with the public keys, in a place that
is protected from modification.

Add a -r option which tells mkimage to mark all keys that it uses
for signing as 'required'.

If some keys are optional and some are required, run mkimage several
times (perhaps with different key directories if some keys are very
secret) using the -F flag to update an existing FIT.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Marek Vasut <marex@denx.de>
Changes in v2:
- Adjust mkimage help to separate out signing options
- Rebase on previous patches

 doc/mkimage.1     | 6 ++++++
 tools/fit_image.c | 9 +++++----
 tools/mkimage.c   | 8 ++++++--
 tools/mkimage.h   | 1 +
 4 files changed, 18 insertions(+), 6 deletions(-)


diff --git a/doc/mkimage.1 b/doc/mkimage.1
index b67a351..14374da 100644
--- a/doc/mkimage.1
+++ b/doc/mkimage.1
@@ -133,6 +133,12 @@  the corresponding public key is written into this file for for run-time
 verification. Typically the file here is the device tree binary used by
+.BI "\-r
+Specifies that keys used to sign the FIT are required. This means that they
+must be verified for the image to boot. Without this option, the verification
+will be optional (useful for testing but not for release).
 List image information:
diff --git a/tools/fit_image.c b/tools/fit_image.c
index d48f571..281c2bd 100644
--- a/tools/fit_image.c
+++ b/tools/fit_image.c
@@ -152,10 +152,11 @@  static int fit_handle_file (struct mkimage_params *params)
 		goto err_mmap;
 	/* set hashes for images in the blob */
-	if (fit_add_verification_data(params->keydir, dest_blob, ptr,
-				      params->comment, 0)) {
-		fprintf (stderr, "%s Can't add hashes to FIT blob",
-			 params->cmdname);
+	if (fit_add_verification_data(params->keydir,
+				      dest_blob, ptr, params->comment,
+				      params->require_keys)) {
+		fprintf(stderr, "%s Can't add hashes to FIT blob\n",
+			params->cmdname);
 		goto err_add_hashes;
diff --git a/tools/mkimage.c b/tools/mkimage.c
index b3b45a4..d312844 100644
--- a/tools/mkimage.c
+++ b/tools/mkimage.c
@@ -270,6 +270,9 @@  main (int argc, char **argv)
 					usage ();
 				params.imagename = *++argv;
 				goto NXTARG;
+			case 'r':
+				params.require_keys = 1;
+				break;
 			case 'R':
 				if (--argc <= 0)
@@ -645,11 +648,12 @@  usage ()
 	fprintf(stderr, "          -D => set options for device tree compiler\n"
 			"          -f => input filename for FIT source\n");
-	fprintf(stderr, "Signing / verified boot options: [-k keydir] [-K dtb] [ -c <comment>]\n"
+	fprintf(stderr, "Signing / verified boot options: [-k keydir] [-K dtb] [ -c <comment>] [-r]\n"
 			"          -k => set directory containing private keys\n"
 			"          -K => write public keys to this .dtb file\n"
 			"          -c => add comment in signature node\n"
-			"          -F => re-sign existing FIT image\n");
+			"          -F => re-sign existing FIT image\n"
+			"          -r => mark keys used as 'required' in dtb\n");
 	fprintf(stderr, "Signing / verified boot not supported (CONFIG_FIT_SIGNATURE undefined)\n");
diff --git a/tools/mkimage.h b/tools/mkimage.h
index 4391ca8..d82be17 100644
--- a/tools/mkimage.h
+++ b/tools/mkimage.h
@@ -78,6 +78,7 @@  struct mkimage_params {
 	const char *keydir;	/* Directory holding private keys */
 	const char *keydest;	/* Destination .dtb for public key */
 	const char *comment;	/* Comment to add to signature node */
+	int require_keys;	/* 1 to mark signing keys as 'required' */