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authorYannick Gicquel <yannick.gicquel@iot.bzh>2016-04-27 16:20:56 +0200
committerRichard Purdie <richard.purdie@linuxfoundation.org>2016-05-06 10:30:57 +0100
commit38d675f568ed67505896f20dd9738ce80feece08 (patch)
treea9c2d182ae7bba823b88e7b2eab5836b40456114
parent9a3f541da305c75418c2eec75ade902717a01b69 (diff)
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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. Signed-off-by: Yannick Gicquel <yannick.gicquel@iot.bzh> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
-rw-r--r--meta/classes/kernel-fitimage.bbclass45
1 files changed, 43 insertions, 2 deletions
diff --git a/meta/classes/kernel-fitimage.bbclass b/meta/classes/kernel-fitimage.bbclass
index 62e0017617..809bd4d698 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
}