Hi Raymond,
On Wed, 24 Jul 2024 at 08:35, Raymond Mao raymond.mao@linaro.org wrote:
Hi Tom,
On Tue, 2 Jul 2024 at 21:26, Tom Rini trini@konsulko.com wrote:
On Tue, Jul 02, 2024 at 11:22:36AM -0700, Raymond Mao wrote:
Integrate MbedTLS v3.6 LTS (currently v3.6.0-RC1) with U-Boot.
Motivations:
- MbedTLS is well maintained with LTS versions.
- LWIP is integrated with MbedTLS and easily to enable HTTPS.
- 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_X509` is for replacing original X509, PKCS7, MSCode, ASN1, and Pubkey parser with MbedTLS. `MBEDTLS_LIB_TLS` is for SSL/TLS (Disabled until LWIP port for MbedTLS is ready). `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 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:
- Decoding of Microsoft Authentication Code.
- Decoding of PKCS#9 Authenticate Attributes.
- Extending MbedTLS PKCS#7 lib to support multiple signer's certificates.
- 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.
Target(QEMU arm64) size-growth when enabling MbedTLS: v1: 6.03% v2: 4.66% v3 & v4: 4.55%
Please see the latest output of bloat-o-meter for the reference of the size-growth on QEMU arm64 target [1].
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.
[1]: bloat-o-meter output between disabling/enabling MbedTLS (QEMU arm64)
add/remove: 206/81 grow/shrink: 19/17 up/down: 55548/-17495 (38053)bloat-o-meter is a bit off then, since buildman shows: u-boot: add: 243/-17, grow: 18/-17 bytes: 65723/-8480 (57243)
(Please use buildman for the size comparisons in the future).
The reason that buildman is showing more growth is because I enable "CONFIG_EFI_SECURE_BOOT=y" in my patch, which is off by default for qemu_arm64. Since the buildman is always comparing one local branch with the 'upstream' (I didn't find a way to let it compare two local branches or maybe I am wrong), I guess I have to first merge one commit with just enabling CONFIG_EFI_SECURE_BOOT to solve this. But I get this makes less value...
Yes, that's one way to do it. It cannot compare two branches. It only compares one commit with the next.
I think it is better to use sandbox for comparison from v5, and I will add one more platform (e.g. imx8mp) for reference.
Regards, Simon