[PATCH v3 05/13] sbsign.bbclass: Add class to sign binaries

[Javier Tia <javier.tia@linaro.org>]

A lot of recipes are using these same steps to sign binaries
for UEFI secure boot.

Authored-by: Mikko Rapeli <mikko.rapeli@linaro.org>
Signed-off-by: Javier Tia <javier.tia@linaro.org>
---
 meta-arm/classes/sbsign.bbclass | 39 +++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 meta-arm/classes/sbsign.bbclass

diff --git a/meta-arm/classes/sbsign.bbclass b/meta-arm/classes/sbsign.bbclass
new file mode 100644
index 00000000..a99c0218
--- /dev/null
+++ b/meta-arm/classes/sbsign.bbclass
@@ -0,0 +1,39 @@
+# Sign binaries for UEFI secure boot
+# Usage in recipes:
+#
+# Set key and cert files in recipe or machine/distro config:
+# SBSIGN_KEY = "db.key"
+# SBSIGN_CERT = "db.crt"
+#
+# Set binary to sign per recipe:
+# SBSIGN_TARGET_BINARY = "${B}/binary_to_sign"
+#
+# Then call do_sbsign() in correct stage of the build
+# do_compile:append() {
+#     do_sbsign
+# }
+
+DEPENDS += "sbsigntool-native"
+
+SBSIGN_KEY ?= "db.key"
+SBSIGN_CERT ?= "db.crt"
+SBSIGN_TARGET_BINARY ?= "binary_to_sign"
+
+# makes sure changed keys trigger rebuild/re-signing
+SRC_URI += "\
+    file://${SBSIGN_KEY} \
+    file://${SBSIGN_CERT} \
+"
+
+# not adding as task since recipes may need to sign binaries at different
+# stages. Instead they can call this function when needed by calling this function
+do_sbsign() {
+    bbnote "Signing ${PN} binary ${SBSIGN_TARGET_BINARY} with ${SBSIGN_KEY} and ${SBSIGN_CERT}"
+    ${STAGING_BINDIR_NATIVE}/sbsign \
+        --key "${UNPACKDIR}/${SBSIGN_KEY}" \
+        --cert "${UNPACKDIR}/${SBSIGN_CERT}" \
+        --output  "${SBSIGN_TARGET_BINARY}.signed" \
+        "${SBSIGN_TARGET_BINARY}"
+    cp "${SBSIGN_TARGET_BINARY}" "${SBSIGN_TARGET_BINARY}.unsigned"
+    cp "${SBSIGN_TARGET_BINARY}.signed" "${SBSIGN_TARGET_BINARY}"
+}
\ No newline at end of file
-- 
2.46.0