Merge patch series "Integrate MbedTLS v3.6 LTS with U-Boot"

Raymond Mao <raymond.mao@linaro.org> says:
Integrate MbedTLS v3.6 LTS (currently v3.6.0) with U-Boot.

Motivations:
------------

1. MbedTLS is well maintained with LTS versions.
2. LWIP is integrated with MbedTLS and easily to enable HTTPS.
3. MbedTLS recently switched license back to GPLv2.

Prerequisite:
-------------

This patch series requires mbedtls git repo to be added as a
subtree to the main U-Boot repo via:
    $ git subtree add --prefix lib/mbedtls/external/mbedtls \
          https://github.com/Mbed-TLS/mbedtls.git \
          v3.6.0 --squash
Moreover, due to the Windows-style files from mbedtls git repo,
we need to convert the CRLF endings to LF and do a commit manually:
    $ git add --renormalize .
    $ git commit

New Kconfig options:
--------------------

`MBEDTLS_LIB` is for MbedTLS general switch.
`MBEDTLS_LIB_CRYPTO` is for replacing original digest and crypto libs with
MbedTLS.
`MBEDTLS_LIB_CRYPTO_ALT` is for using original U-Boot crypto libs as
MbedTLS crypto alternatives.
`MBEDTLS_LIB_X509` is for replacing original X509, PKCS7, MSCode, ASN1,
and Pubkey parser with MbedTLS.
By default `MBEDTLS_LIB_CRYPTO_ALT` and `MBEDTLS_LIB_X509` are selected
when `MBEDTLS_LIB` is enabled.
`LEGACY_CRYPTO` is introduced as a main switch for legacy crypto library.
`LEGACY_CRYPTO_BASIC` is for the basic crypto functionalities and
`LEGACY_CRYPTO_CERT` is for the certificate related functionalities.
For each of the algorithm, a pair of `<alg>_LEGACY` and `<alg>_MBEDTLS`
Kconfig options are introduced. Meanwhile, `SPL_` Kconfig options are
introduced.

In this patch set, MBEDTLS_LIB, MBEDTLS_LIB_CRYPTO and MBEDTLS_LIB_X509
are by default enabled in qemu_arm64_defconfig and sandbox_defconfig
for testing purpose.

Patches for external MbedTLS project:
-------------------------------------

Since U-Boot uses Microsoft Authentication Code to verify PE/COFFs
executables which is not supported by MbedTLS at the moment,
addtional patches for MbedTLS are created to adapt with the EFI loader:
1. Decoding of Microsoft Authentication Code.
2. Decoding of PKCS#9 Authenticate Attributes.
3. Extending MbedTLS PKCS#7 lib to support multiple signer's certificates.
4. MbedTLS native test suites for PKCS#7 signer's info.

All above 4 patches (tagged with `mbedtls/external`) are submitted to
MbedTLS project and being reviewed, eventually they should be part of
MbedTLS LTS release.
But before that, please merge them into U-Boot, otherwise the building
will be broken when MBEDTLS_LIB_X509 is enabled.

See below PR link for the reference:
https://github.com/Mbed-TLS/mbedtls/pull/9001

Miscellaneous:
--------------

Optimized MbedTLS library size by tailoring the config file
and disabling all unnecessary features for EFI loader.
From v2, original libs (rsa, asn1_decoder, rsa_helper, md5, sha1, sha256,
sha512) are completely replaced when MbedTLS is enabled.
From v3, the size-growth is slightly reduced by refactoring Hash functions.
From v6, smaller implementations for SHA256 and SHA512 are enabled and
target size reduce significantly.
Target(QEMU arm64) size-growth when enabling MbedTLS:
v1: 6.03%
v2: 4.66%
v3 - v5: 4.55%
v6: 2.90%

Tests done:
-----------

EFI Secure Boot test (EFI variables loading and verifying, EFI signed image
verifying and booting) via U-Boot console.
EFI Secure Boot and Capsule sandbox test passed.

Known issues:
-------------

None.

Link: https://lore.kernel.org/u-boot/20241003215112.3103601-1-raymond.mao@linaro.org/

1 files changed, 62 insertions, 0 deletions

diff --git a/lib/mbedtls/sha256.c b/lib/mbedtls/sha256.c
new file mode 100644
index 00000000000..24aa58fa674
--- /dev/null
+++ b/lib/mbedtls/sha256.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Hash shim layer on MbedTLS Crypto library
+ *
+ * Copyright (c) 2024 Linaro Limited
+ * Author: Raymond Mao <raymond.mao@linaro.org>
+ */
+#ifndef USE_HOSTCC
+#include <cyclic.h>
+#endif /* USE_HOSTCC */
+#include <u-boot/sha256.h>
+
+const u8 sha256_der_prefix[SHA256_DER_LEN] = {
+	0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86,
+	0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05,
+	0x00, 0x04, 0x20
+};
+
+void sha256_starts(sha256_context *ctx)
+{
+	mbedtls_sha256_init(ctx);
+	mbedtls_sha256_starts(ctx, 0);
+}
+
+void
+sha256_update(sha256_context *ctx, const uint8_t *input, uint32_t length)
+{
+	mbedtls_sha256_update(ctx, input, length);
+}
+
+void sha256_finish(sha256_context *ctx, uint8_t digest[SHA256_SUM_LEN])
+{
+	mbedtls_sha256_finish(ctx, digest);
+	mbedtls_sha256_free(ctx);
+}
+
+void sha256_csum_wd(const unsigned char *input, unsigned int ilen,
+		    unsigned char *output, unsigned int chunk_sz)
+{
+	sha256_context ctx;
+
+	sha256_starts(&ctx);
+
+	if (IS_ENABLED(CONFIG_HW_WATCHDOG) || IS_ENABLED(CONFIG_WATCHDOG)) {
+		const unsigned char *curr = input;
+		const unsigned char *end = input + ilen;
+		int chunk;
+
+		while (curr < end) {
+			chunk = end - curr;
+			if (chunk > chunk_sz)
+				chunk = chunk_sz;
+			sha256_update(&ctx, curr, chunk);
+			curr += chunk;
+			schedule();
+		}
+	} else {
+		sha256_update(&ctx, input, ilen);
+	}
+
+	sha256_finish(&ctx, output);
+}