e3cadcacd798effe83b1593dba1ee0e3d84cf6e4 |
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23-Feb-2017 |
David Zeuthen <zeuthen@google.com> |
Rework how versioning work. Instead of listing the version of avbtool that generated the struct (which is not very useful), convey the minimum required libavb version needed to parse the structure. This is a lot more useful as it can be used at runtime to reject updates requiring a newer libavb than what is on the device (conveyed via androidboot.vbmeta.avb_version). Also add a human-readable release-string field that describes what tool (typically avbtool) was used to generate the data. Emphasize that one cannot make assumptions about the format and it's only there to aid in debugging. Also make it possible to easily append build-specific information to this string. Add a third version number field that can be bumped when doing bug-fix releases that don't add any new features. This is groundwork needed for a release process. Document all this in the README file. Also rename androidboot.vbmeta.version to androidboot.vbmeta.avb_version since it conveys the version of libavb used in the bootloader. Add avb_version_string() and suggest that this should be used in bootloaders to convey what version of libavb is being used on the device in debug/diagnostics output. Update examples/uefi to use this. Bug: 35322304 Bug: 32414650 Test: New unit tests and all unit tests pass. Test: Manually tested on UEFI based bootloader. Change-Id: Iae52a751c84fe4ea4473803d6f4e978720737511
/external/avb/test/avb_vbmeta_image_unittest.cc
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4b6a634e48353da1e119ebe0287299f7b919d778 |
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03-Jan-2017 |
David Zeuthen <zeuthen@google.com> |
Fix-up coding style and add PREUPLOAD.cfg file. Previous commits broke the style specified our .clang-format file - fixed this by running it through clang-format(1). During this process discovered that I've been invoking clang-format(1) without the --style=file option meaning that our .clang-format file actually hadn't been used at all. So there's a rather big amount of formatting changes in this CL. Also replaced the .clang-format symlink target to ../../build/tools/brillo-clang-format with our own file since the brillo one may go away in the future or not exist at all. Finally, added a PREULOAD.cfg file to do this on every commit. See https://android.googlesource.com/platform/tools/repohooks/ for more information about how this works. Bug: None Test: Manually tested. Test: All unit tests pass. Change-Id: I6461478a62efd81689bc4316c22f758e7f98f59f
/external/avb/test/avb_vbmeta_image_unittest.cc
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72d5790de1e0e6ee5e8b185e59d102cbb46a986a |
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13-Dec-2016 |
Darren Krahn <dkrahn@google.com> |
test: Add abstract delegate and better rollback indexes to FakeAvbOps The abstract delegate allows tests to override and set their own delegate, effectively customizing the fake behavior with minimal fuss. A test could even use gmock to implement a delegate. Rollback indexes will not necessarily be contiguous (0, 1, 2, ...) going forward so handling them via a index-to-value map is better than a strict vector. Also, this CL moves C++ code, including tests, into a namespace. Bug: 33553097 Test: unit Change-Id: Ib53637c8b9320d9847b079aad79ce4fbd8ffc701
/external/avb/test/avb_vbmeta_image_unittest.cc
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fd41eb9a7848ad8d2ae0a80186e461741bf134f1 |
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17-Nov-2016 |
David Zeuthen <zeuthen@google.com> |
Add way to disable dm-verity allowing rootfs to be writable. This feature already exist in Android's current verified boot implementation and can be enabled by running 'adb disable-verity'. As it's very useful for developers (it allows replacing e.g. binaries on the root filesystem) we want AVB to have this feature as well. First, add a 'flags' field in the VBMeta struct with a single possible flag value HASHTREE_DISABLED (we can add more flags in the future). Second, to enable the feature we essentially need to pass root=PARTUUID=$(ANDROID_SYSTEM_PARTUUID) instead of dm="1 vroot ... PARTUUID=$(ANDROID_SYSTEM_PARTUUID) ... " root=0xfd00 To do this cleanly and keep all the details about dm-verity setup outside the bootloader binary, introduce a flags field to the command-line descriptor allowing the bootloader to skip the command-line snippet depending on whether HASHTREE_DISABLED is set or not. With this in place, modify avbtool to generate two kernel command-line descriptors - one if HASHTREE_DISABLED is set and one if it's not. One note is that the VBMeta flag HASHTREE_DISABLED will never be used at image build time. Instead, it's expected that 'adb disable-verity' will set the flag by writing to vbmeta_a or vbmeta_b directly. This will of course cause the image to not be verified but if the device is unlocked the bootloader will boot it anyway .. this is because of the previous CL with subject "Enable operations on unlocked devices." I tried all this using my toy UEFI-based bootloader using libavb and here's the result. First the bootloader output when processing a freshly built image (with lots of thing deleted for brevity): ab_result=OK, slot_suffix=_a, command-line='dm="1 vroot none ro 1,0 [...]" root=0xfd00 androidboot.slot_suffix=_a androidboot.vbmeta.device_state=unlocked [...]' and once we've get a shell remounting rootfs rw fails: $ su # mount -orw,remount / '/dev/root' is read-only It's possible however to set the new HASHTREE_DISABLED flag by writing to vbmeta_a: # echo -n -e \\x01 | dd bs=1 oseek=123 count=1 \ of=/dev/block/pci/pci0000\:00/0000\:00\:01.1/by-name/vbmeta_a 1+0 records in 1+0 records out 1 bytes transferred in 0.001 secs (1000 bytes/sec) When rebooting the bootloader now outputs the following: ab_result=OK_WITH_VERIFICATION_ERROR, slot_suffix=_a, command-line='root=PARTUUID=c2531a08-1ff2-4c3e-9d9d-a50e5abd02c8 androidboot.slot_suffix=_a androidboot.vbmeta.device_state=unlocked [...]' and it's now possible to remount the root filesystem and write to it: $ su # mount -orw,remount / # echo foo > /bar # cat /bar foo with changes persisting across reboots. Needless to say, disabling hashtree verification like this will ONLY work if the device is unlocked. This is because the HASHTREE_DISABLED flag is in the verified data. Test: New unit tests and unit tests pass. Test: Manually tested on UEFI based bootloader, see above. Bug: 32949911 Change-Id: I9474ddd5f442be369cb0a551f03ac181cc41a265
/external/avb/test/avb_vbmeta_image_unittest.cc
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18666abc5d8276a743111e6c3608e66f6c85fb51 |
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15-Nov-2016 |
David Zeuthen <zeuthen@google.com> |
Make it possible to include public key metadata. A new option --public_key_metadata can be used at image build time to include a "public key metadata" blob in the vbmeta struct and this data is passed to the validate_vbmeta_public_key() AvbOps operation along with the public key. The use-case for this option is a device where the root-of-trust embedded in the device is different from the key used to sign AVB metadata. Specifically, the public key metadata blob can be data signed by the device root-of-trust and the data could assert the trust chain between this root-of-trust and the AVB public key used to sign the AVB metadata. (This change breaks the on-disk image format but that's OK because we're still pre-1.0 with respect to image format stability guarantees.) Bug: 32736356 Test: New unit tests and all unit tests pass. Test: Tested in UEFI-based bootloader in qemu. Change-Id: I7b9c3bf2f9326b5bb5659b2a431a59a5c9016aff
/external/avb/test/avb_vbmeta_image_unittest.cc
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baf59e232e48d0111e4b38f74c60c89e6f8f0b14 |
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14-Nov-2016 |
David Zeuthen <zeuthen@google.com> |
libavb: Move all A/B functionality into separate libavb_ab/ directory. This new libavb_ab "library" depends on libavb "library" insofar that it's using the same abstractions (system dependencies and operations). For easy integration the newly introduced AvbABOps struct extends the AvbOps struct so users can build just a single struct and use that for both. Also emphasize in README that libavb_ab usage is optional and that it's possible to integrate libavb with another A/B stack. (The quotes in use for "library" above is because these are not really libraries from a system-integration perspective. That is, 3rd party is expected to integrate this source-code with their own build-system and toolchain.) Since we now have multiple libraries - at least from the point of view of how it's used in unit tests - change Android.mk such that library users need to use libavb/libavb.h and libavb_ab/libavb_ab.h instead of just e.g. libavb.h. Test: Unit tests pass Test: Tested in UEFI-based bootloader in qemu. Test: Tested boot_control.avb.so in same UEFI-based system. Bug: None Change-Id: I19ea8f6bd1e63b2617b0e9fa9fc3b2a68ac4a92e
/external/avb/test/avb_vbmeta_image_unittest.cc
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c612e2e353444f6ad714e43702c2afd057516254 |
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16-Sep-2016 |
David Zeuthen <zeuthen@google.com> |
Switch to MIT license. BUG=31508897 TEST=Unit tests pass. Change-Id: I790afce2889e3dfaf6a53c02ccaaec3544229a9c
/external/avb/test/avb_vbmeta_image_unittest.cc
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21e95266704e572ced1c633bbc4aea9f42afa0a5 |
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27-Jul-2016 |
David Zeuthen <zeuthen@google.com> |
Add common verified boot tools and library. This code is originally from the Brillo project but has been adapted for use in all of Android. It consists of a tool - avbtool - for working with images (e.g. boot.img, system.img). See the README file for how it's integrated into the Android build system and how to enable it. The main job of avbtool is to create vbmeta.img which is the top-level object for verified boot. This image is designed to go into the vbmeta partition (or, if using A/B, the slot in question e.g. vbmeta_a or vbmeta_b) and be of minimal size (for out-of-band updates). The vbmeta image is cryptographically signed and contains verification data (e.g. cryptographic digests) for verifying boot.img, system.img, and other partitions/images. The vbmeta image can also contain references to other partitions where verification data is stored as well as a public key indicating who should sign the verification data. This indirection provides delegation, that is, it allows a 3rd party to control content on a given partition by including the public key said 3rd party is using to sign the data with, in vbmeta.img. By design, this authority can be easily revoked by simply updating vbmeta.img with new descriptors for the partition in question. Storing signed verification data on other images - for example boot.img and system.img - is also done with avbtool. In addition to avbtool, a library - libavb - is provided. This library performs all verification on the device side e.g. it starts by loading the vbmeta partition, checks the signature, and then goes on to load the boot partition for verification. The libavb library is intended to be used in both boot loaders and inside Android. It has a simple abstraction for system dependencies (see libavb/avb_sysdeps.h) as well as operations that the boot loader or OS is expected to implement (see libavb/avb_ops.h). In addition to handling verified boot, libavb will in the future be extended to handle A/B selection in a way that can be used in the device's fastboot implementation, its boot loader, and its boot_control HAL implementation. This will be implemented in a future CL. BUG=29414516 TEST=Unit tests for avbtool and libavb + unit tests pass. Change-Id: I69ee86878e21fa718faccfc56eb0b1f40707d847
/external/avb/test/avb_vbmeta_image_unittest.cc
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