[PATCH v15 17/28] x86: Add early SHA-1 support for Secure Launch early measurements

Ross Philipson
2025-12-15T23:41:42Z

From: "Daniel P. Smith" <dpsmith@apertussolutions.com>

Secure Launch is written to be compliant with the Intel TXT Measured Launch
Developer's Guide. The MLE Guide dictates that the system can be configured to
use both the SHA-1 and SHA-2 hashing algorithms.

Regardless of the preference towards SHA-2, if the firmware elected to start
with the SHA-1 and SHA-2 banks active and the dynamic launch was configured to
include SHA-1, Secure Launch is obligated to record measurements for all
algorithms requested in the launch configuration.

The user environment or the integrity management does not desire to use SHA-1,
it is free to just ignore the SHA-1 bank in any integrity operation with the
TPM. If there is a larger concern about the SHA-1 bank being active, it is free
to deliberately cap the SHA-1 PCRs, recording the event in the D-RTM log.

Signed-off-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Signed-off-by: Ross Philipson <ross.philipson@oracle.com>
---
arch/x86/boot/compressed/Makefile | 4 ++++
arch/x86/boot/compressed/sha1.c | 7 +++++++
2 files changed, 11 insertions(+)
create mode 100644 arch/x86/boot/compressed/sha1.c

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 74657589264d..69592146ced7 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -112,6 +112,10 @@ ifdef CONFIG_EFI_SBAT
$(obj)/sbat.o: $(CONFIG_EFI_SBAT_FILE)
endif

+slaunch-objs += $(obj)/sha1.o
+
+vmlinux-objs-$(CONFIG_SECURE_LAUNCH) += $(slaunch-objs)
+
$(obj)/vmlinux: $(vmlinux-objs-y) $(vmlinux-libs-y) FORCE
$(call if_changed,ld)

diff --git a/arch/x86/boot/compressed/sha1.c b/arch/x86/boot/compressed/sha1.c
new file mode 100644
index 000000000000..dd1b4cf5caf5
--- /dev/null
+++ b/arch/x86/boot/compressed/sha1.c
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2025 Apertus Solutions, LLC.
+ */
+
+#undef CONFIG_CRYPTO_LIB_SHA1_ARCH
+#include "../../../../lib/crypto/sha1.c"
--
2.43.7