Hi Simon, On Sat, 17 Aug 2024 at 11:58, Simon Glass <s...@chromium.org> wrote:
> Hi Raymond, > > On Fri, 16 Aug 2024 at 15:44, Raymond Mao <raymond....@linaro.org> wrote: > > > > 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_X509` is for replacing original X509, PKCS7, MSCode, ASN1, > > and Pubkey parser with MbedTLS. > > `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% > > > > Please see the latest output from buildman for size-growth on QEMU arm64, > > Sandbox and Nanopi A64. [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. > > I wonder if we could leave out the SHA stuff? The algorithms are > stable and this would seem to avoid much of the size growth, and all > the pain of trying to integrate another yet another hashing layer (we > already have normal, progressive and h/w acceleration, plus > UCLASS_HASH which h/w acceleration should use but that migration never > happened). I struggle to see any benefit in replacing U-Boot's very > solid hashing infra with something else, particularly as this series > adds yet another. Better to invest the time to refactor it. I asked > about this before and was told that it would happen 'later'. Let's > just not change it at all, then it is more likely someone will sort it > out. > > Unfortunately, MbedTLS depends on its own digest layer. Unless we patch MbedTLS to allow an external digest library from U-Boot ... > Also, if MbedTLS is wanting to be a general library for TLS (I assume > transport-local security, not thread-local storage) perhaps it might > consider changing to non-Windows newlines, or perhaps even kernel code > style? > > We can feedback this to the MbedTLS project when the first series are accepted. Regards, Raymond
