efi_capsule: Move signature from DTB to .rodata
The capsule signature is now part of our DTB. This is problematic when a
user is allowed to change/fixup that DTB from U-Boots command line since he
can overwrite the signature as well.
So Instead of adding the key on the DTB, embed it in the u-boot binary it
self as part of it's .rodata. This assumes that the U-Boot binary we load
is authenticated by a previous boot stage loader.
Reviewed-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>
Tested-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>
Tested-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/lib/efi_loader/efi_capsule_key.S b/lib/efi_loader/efi_capsule_key.S
new file mode 100644
index 0000000..58f00b8
--- /dev/null
+++ b/lib/efi_loader/efi_capsule_key.S
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * .esl cert for capsule authentication
+ *
+ * Copyright (c) 2021, Ilias Apalodimas <ilias.apalodimas@linaro.org>
+ */
+
+#include <config.h>
+
+.section .rodata.capsule_key.init,"a"
+.balign 16
+.global __efi_capsule_sig_begin
+__efi_capsule_sig_begin:
+.incbin CONFIG_EFI_CAPSULE_KEY_PATH
+__efi_capsule_sig_end:
+.global __efi_capsule_sig_end
+.balign 16