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2020-12-03cbfs: Add verification for RO CBFS metadata hashJulius Werner
This patch adds the first stage of the new CONFIG_CBFS_VERIFICATION feature. It's not useful to end-users in this stage so it cannot be selected in menuconfig (and should not be used other than for development) yet. With this patch coreboot can verify the metadata hash of the RO CBFS when it starts booting, but it does not verify individual files yet. Likewise, verifying RW CBFSes with vboot is not yet supported. Verification is bootstrapped from a "metadata hash anchor" structure that is embedded in the bootblock code and marked by a unique magic number. This anchor contains both the CBFS metadata hash and a separate hash for the FMAP which is required to find the primary CBFS. Both are verified on first use in the bootblock (and halt the system on failure). The CONFIG_TOCTOU_SAFETY option is also added for illustrative purposes to show some paths that need to be different when full protection against TOCTOU (time-of-check vs. time-of-use) attacks is desired. For normal verification it is sufficient to check the FMAP and the CBFS metadata hash only once in the bootblock -- for TOCTOU verification we do the same, but we need to be extra careful that we do not re-read the FMAP or any CBFS metadata in later stages. This is mostly achieved by depending on the CBFS metadata cache and FMAP cache features, but we allow for one edge case in case the RW CBFS metadata cache overflows (which may happen during an RW update and could otherwise no longer be fixed because mcache size is defined by RO code). This code is added to demonstrate design intent but won't really matter until RW CBFS verification can be supported. Signed-off-by: Julius Werner <jwerner@chromium.org> Change-Id: I8930434de55eb938b042fdada9aa90218c0b5a34 Reviewed-on: https://review.coreboot.org/c/coreboot/+/41120 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2020-12-03cbfstool: Use cbfs_serialized.h and standard vboot helpersJulius Werner
This patch reduces some code duplication in cbfstool by switching it to use the CBFS data structure definitions in commonlib rather than its own private copy. In addition, replace a few custom helpers related to hash algorithms with the official vboot APIs of the same purpose. Signed-off-by: Julius Werner <jwerner@chromium.org> Change-Id: I22eae1bcd76d85fff17749617cfe4f1de55603f4 Reviewed-on: https://review.coreboot.org/c/coreboot/+/41117 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Aaron Durbin <adurbin@chromium.org> Reviewed-by: Wim Vervoorn <wvervoorn@eltan.com>
2020-12-02cbfs: Port cbfs_load() and cbfs_map() to new APIJulius Werner
This patch adapts cbfs_load() and cbfs_map() to use the new CBFS API directly, rather than through cbfs_boot_locate(). For cbfs_load() this means that attribute metadata does not need to be read twice. Change-Id: I754cc34b1c1471129e15475aa0f1891e02439a02 Signed-off-by: Julius Werner <jwerner@chromium.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/39305 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Aaron Durbin <adurbin@chromium.org>
2020-11-21cbfs: Add metadata cacheJulius Werner
This patch adds a new CBFS "mcache" (metadata cache) -- a memory buffer that stores the headers of all CBFS files. Similar to the existing FMAP cache, this cache should reduce the amount of SPI accesses we need to do every boot: rather than having to re-read all CBFS headers from SPI flash every time we're looking for a file, we can just walk the same list in this in-memory copy and finally use it to directly access the flash at the right position for the file data. This patch adds the code to support the cache but doesn't enable it on any platform. The next one will turn it on by default. Change-Id: I5b1084bfdad1c6ab0ee1b143ed8dd796827f4c65 Signed-off-by: Julius Werner <jwerner@chromium.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/38423 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Aaron Durbin <adurbin@chromium.org>
2020-10-30commonlib/bsd: Add new CBFS core implementationJulius Werner
This patch adds a new CBFS implementation that is intended to replace the existing commonlib/cbfs.c. The new implementation is designed to meet a bunch of current and future goals that in aggregate make it easier to start from scratch than to adapt the exisiting implementation: 1. Be BSD-licensed so it can evetually be shared with libpayload. 2. Allow generating/verifying a metadata hash for future CBFS per-file verification (see [1][2]). 3. Be very careful about reading (not mmaping) all data only once, to be suitable for eventual TOCTOU-safe verification. 4. Make it possible to efficiently implement all current and future firmware use cases (both with and without verification). The main primitive is the cbfs_walk() function which will traverse a CBFS and call a callback for every file. cbfs_lookup() uses this to implement the most common use case of finding a file so that it can be read. A host application using this code (e.g. coreboot, libpayload, cbfstool) will need to provide a <cbfs_glue.h> header to provide the glue to access the respective CBFS storage backend implementation. This patch merely adds the code, the next patch will integrate it into coreboot. [1]: https://www.youtube.com/watch?v=Hs_EhewBgtM [2]: https://osfc.io/uploads/talk/paper/47/The_future_of_firmware_verification_in_coreboot.pdf (Note: In early discussions the metadata hash was called "master hash".) Change-Id: Ica64c1751fa37686814c0247460c399261d5814c Signed-off-by: Julius Werner <jwerner@chromium.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/38421 Reviewed-by: Aaron Durbin <adurbin@chromium.org> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2020-09-21src/commonlib: Drop unneeded empty linesElyes HAOUAS
Change-Id: Ib3db132aa649b6895f41290df049f87a9f36dc52 Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr> Reviewed-on: https://review.coreboot.org/c/coreboot/+/44606 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>
2020-09-14util/cbfstool: extend includes in commonlibIdwer Vollering
Certain non-Linux OSes require an include file in different places. Build tested on Linux, FreeBSD. Change-Id: Icd81c2a96c608589ce2ec8f4b883fd4e584776b1 Signed-off-by: Idwer Vollering <vidwer@gmail.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/38648 Reviewed-by: Angel Pons <th3fanbus@gmail.com> Reviewed-by: Julius Werner <jwerner@chromium.org> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2020-06-02commonlib: Add CBFS_TYPE_BOOTBLOCKWim Vervoorn
Add CBFS_TYPE_BOOTBLOCK to allow accessing the bootblock as a CBFS file. BUG=N/A TEST=build Change-Id: Ibb03ac3a6cd8711e0402e47335bb8e110c6ef61a Signed-off-by: Wim Vervoorn <wvervoorn@eltan.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/41824 Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com> Reviewed-by: Frans Hendriks <fhendriks@eltan.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2020-03-30helpers: Add a helper macro for calculating power of 2Furquan Shaikh
This change adds a helper macro POWER_OF_2 that is useful for calculating the requested power of 2. Change-Id: Ie70f93b6ac175699c11cae7d8f023a52cce01e88 Signed-off-by: Furquan Shaikh <furquan@google.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/39881 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Aaron Durbin <adurbin@chromium.org>
2020-01-28commonlib: Add commonlib/bsdJulius Werner
This patch creates a new commonlib/bsd subdirectory with a similar purpose to the existing commonlib, with the difference that all files under this subdirectory shall be licensed under the BSD-3-Clause license (or compatible permissive license). The goal is to allow more code to be shared with libpayload in the future. Initially, I'm going to move a few files there that have already been BSD-licensed in the existing commonlib. I am also exracting most contents of the often-needed <commonlib/helpers.h> as long as they have either been written by me (and are hereby relicensed) or have an existing equivalent in BSD-licensed libpayload code. I am also relicensing <commonlib/compression.h> (written by me) and <commonlib/compiler.h> (same stuff exists in libpayload). Finally, I am extracting the cb_err error code definitions from <types.h> into a new BSD-licensed header so that future commonlib/bsd code can build upon a common set of error values. I am making the assumption here that the enum constants and the half-sentence fragments of documentation next to them by themselves do not meet the threshold of copyrightability. Change-Id: I316cea70930f131e8e93d4218542ddb5ae4b63a2 Signed-off-by: Julius Werner <jwerner@chromium.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/38420 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Patrick Rudolph <siro@das-labor.org>