[gnome-continuous-yocto/gnomeostree-3.28-rocko: 91/8267] kernel: fitimage: basic support for fitimage signature

[Emmanuele Bassi <ebassi src gnome org>]

commit f088e693b2bf960ce027be75e835371abfe74e95
Author: Yannick Gicquel <yannick gicquel iot bzh>
Date:   Wed Apr 27 16:20:56 2016 +0200

    kernel: fitimage: basic support for fitimage signature
    
    This is an initial support of fitImage signature to enable U-Boot verified
    boot. This feature is implemented by adding a signature tag to the
    configuration section of the generated fit-image.its file.
    
    When a UBOOT_SIGN_ENABLE variable is set to "1", the signature procedure is
    activated and performs a second call to mkimage to sign the fitImage file and
    to include the public key in the deployed U-Boot device tree blob. (This
    implementation depends on the use of CONFIG_OF_SEPARATE in U-Boot.)
    
    As the U-Boot device tree blob is appended in the deploy dir, a dependency
    on 'u-boot:do_deploy' is added when the feature is activated.
    
    (From OE-Core rev: 38d675f568ed67505896f20dd9738ce80feece08)
    
    Signed-off-by: Yannick Gicquel <yannick gicquel iot bzh>
    Signed-off-by: Richard Purdie <richard purdie linuxfoundation org>

 meta/classes/kernel-fitimage.bbclass |   45 ++++++++++++++++++++++++++++++++-
 1 files changed, 43 insertions(+), 2 deletions(-)
---
diff --git a/meta/classes/kernel-fitimage.bbclass b/meta/classes/kernel-fitimage.bbclass
index 62e0017..809bd4d 100644
--- a/meta/classes/kernel-fitimage.bbclass
+++ b/meta/classes/kernel-fitimage.bbclass
@@ -1,4 +1,4 @@
-inherit kernel-uboot
+inherit kernel-uboot uboot-sign
 
 python __anonymous () {
     kerneltype = d.getVar('KERNEL_IMAGETYPE', True)
@@ -15,6 +15,13 @@ python __anonymous () {
         image = d.getVar('INITRAMFS_IMAGE', True)
         if image:
             d.appendVarFlag('do_assemble_fitimage', 'depends', ' ${INITRAMFS_IMAGE}:do_image_complete')
+
+        # Verified boot will sign the fitImage and append the public key to
+        # U-boot dtb. We ensure the U-Boot dtb is deployed before assembling
+        # the fitImage:
+        if d.getVar('UBOOT_SIGN_ENABLE', True):
+            uboot_pn = d.getVar('PREFERRED_PROVIDER_u-boot', True) or 'u-boot'
+            d.appendVarFlag('do_assemble_fitimage', 'depends', ' %s:do_deploy' % uboot_pn)
 }
 
 # Options for the device tree compiler passed to mkimage '-D' feature:
@@ -132,6 +139,9 @@ EOF
 fitimage_emit_section_config() {
 
        conf_csum="sha1"
+       if [ -n "${UBOOT_SIGN_ENABLE}" ] ; then
+               conf_sign_keyname="${UBOOT_SIGN_KEYNAME}"
+       fi
 
        # Test if we have any DTBs at all
        if [ -z "${2}" ] ; then
@@ -152,6 +162,26 @@ fitimage_emit_section_config() {
                         hash@1 {
                                 algo = "${conf_csum}";
                         };
+EOF
+
+       if [ ! -z "${conf_sign_keyname}" ] ; then
+
+               if [ -z "${2}" ] ; then
+                       sign_line="sign-images = \"kernel\";"
+               else
+                       sign_line="sign-images = \"fdt\", \"kernel\";"
+               fi
+
+               cat << EOF >> fit-image.its
+                        signature@1 {
+                                algo = "${conf_csum},rsa2048";
+                                key-name-hint = "${conf_sign_keyname}";
+                                sign-images = "fdt", "kernel";
+                        };
+EOF
+       fi
+
+       cat << EOF >> fit-image.its
                 };
 EOF
 }
@@ -160,7 +190,7 @@ do_assemble_fitimage() {
        if test "x${KERNEL_IMAGETYPE}" = "xfitImage" ; then
                kernelcount=1
                dtbcount=""
-               rm -f fit-image.its
+               rm -f fit-image.its arch/${ARCH}/boot/fitImage
 
                fitimage_emit_fit_header
 
@@ -216,6 +246,17 @@ do_assemble_fitimage() {
                        ${@'-D "${UBOOT_MKIMAGE_DTCOPTS}"' if len('${UBOOT_MKIMAGE_DTCOPTS}') else ''} \
                        -f fit-image.its \
                        arch/${ARCH}/boot/fitImage
+
+               #
+               # Step 5: Sign the image and add public key to U-Boot dtb
+               #
+               if test -n "${UBOOT_SIGN_ENABLE}"; then
+                       uboot-mkimage \
+                               ${@'-D "${UBOOT_MKIMAGE_DTCOPTS}"' if len('${UBOOT_MKIMAGE_DTCOPTS}') else 
''} \
+                               -F -k "${UBOOT_SIGN_KEYDIR}" \
+                               -K "${DEPLOY_DIR_IMAGE}/${UBOOT_DTB_BINARY}" \
+                               -r arch/${ARCH}/boot/fitImage
+               fi
        fi
 }