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* rollback: Add function to fetch secretNicolas Boichat2017-06-141-0/+10
| | | | | | | | | | | | | | BRANCH=none BUG=b:38486828 TEST=Flash hammer Change-Id: I50088a78e75d6ea8d62e439fdc8bf18d46319462 Reviewed-on: https://chromium-review.googlesource.com/532474 Commit-Ready: Nicolas Boichat <drinkcat@chromium.org> Tested-by: Nicolas Boichat <drinkcat@chromium.org> Reviewed-by: Mattias Nissler <mnissler@chromium.org> Reviewed-by: Randall Spangler <rspangler@chromium.org> Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
* hammer: Add board_get_entropy function (and test)Nicolas Boichat2017-06-061-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | This function will be used to generate some entropy using the Clock Recovery System. BRANCH=none BUG=b:38486828 TEST=make BOARD=hammer -j tests ./util/flash_ec --board=hammer --image=build/hammer/test-entropy.bin EC console: runtest TEST=Test fails when no USB connection is active TEST=Test passes when USB connection is active TEST=Pasting the values into: tr ';' '\n' | awk 'BEGIN { e = 0; tot=16384.0 } { p = $1/tot; if (p > 0) { e -= p*log(p)/log(2) } } END { print e }' shows an entropy > 4 bits per sample. Change-Id: I2363c7bce42c72c33ef0bf3f099d709ee9c13d13 Reviewed-on: https://chromium-review.googlesource.com/518608 Commit-Ready: Nicolas Boichat <drinkcat@chromium.org> Tested-by: Nicolas Boichat <drinkcat@chromium.org> Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
* rollback: Add option to store secret in rollback infoNicolas Boichat2017-05-251-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For pairing purpose, we want to store some secret random number in the base. The most convenient location for this is the rollback region. Since the rollback region can now be updated without incrementing rollback_min_version (when we add entropy to the secret), we need to add an increasing id to tell the code which rollback region is the latest. We also add console commands to manually add entropy. BRANCH=none BUG=b:38486828 TEST=Flash hammer (with or without CONFIG_ROLLBACK_ENTROPY_SIZE set) rollbackinfo => 1 version 0 block, 1 empty block, RW verifies correctly. rollbackupdate 0; rollbackinfo => No change rollbackupdate 1; reboot => RO refuses to jump to RW only when CONFIG_ROLLBACK_ENTROPY_SIZE is set: rollbackinfo => Secret is [00..00] on both blocks (so the data was copied correctly) rollbackupdate 2, 3, 4; rollbackinfo => Writes alternate between the 2 blocks. rollbackupdate 2 => Refuses to downgrade version TEST=From blank secret [00..00], 'rollbackaddent Hello' updates it to [ba..fa], which matches the output of: (dd if=/dev/zero bs=1 count=32; echo -n Hello) | sha256sum Change-Id: I79c3e790e56e21958cc1b4ba05bd4e5f359d3090 Reviewed-on: https://chromium-review.googlesource.com/511985 Commit-Ready: Nicolas Boichat <drinkcat@chromium.org> Tested-by: Nicolas Boichat <drinkcat@chromium.org> Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
* rollback: Update and lock rollback block as part of rwsig verificationNicolas Boichat2017-04-111-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is done at RO stage. If the rollback region is unprotected, update it to match the version in the RW image. If the rollback region is protected, we can't do that update, so we wait for RW to unlock that region (presumably after AP has verified that image is somewhat functional) before updating it. BRANCH=none BUG=b:35586219 TEST=flashwp true; reboot => hammer reboots twice flashinfo shows RO+rollback protected: Flags: wp_gpio_asserted ro_at_boot ro_now rollback_at_boot rollback_now Protected now: YYYYYYYY YYYYYYYY Y....... ........ TEST=Hack version.c to add "+1" to rollback_version, check that RO updates ROLLBACK info block on first boot. TEST=Use hack above, convert rwsig to separate task, add 5000 ms delay in rwsig just before rollback information is updated. Then: Quickly type: flashwp true; reboot; flashwp all; reboot => Wait for system to jump to RW rollbackinfo => minimum version 0 flashwp norb; reboot; wait for jump to RW rollbackinfo => minimum version 1 Change-Id: I78e502315c611c5edaf34b8d70a12fedd3e57bdf Reviewed-on: https://chromium-review.googlesource.com/452816 Commit-Ready: Nicolas Boichat <drinkcat@chromium.org> Tested-by: Nicolas Boichat <drinkcat@chromium.org> Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
* common/rollback: Add support for rollback protectionNicolas Boichat2017-04-061-0/+32
Implement actual rollback protection. First, we add a new field in the version structure, which is an incrementing integer (we'll start by shipping images with version 0, and gradually increase the number as required). This allows us to release new versions of the EC without necessarily bumping the rollback protection. For the rollback protection block itself, it contains 2 sub-blocks of equal size (normally, 2k), that are individually erasable. The rollback code looks at both, and takes the most restrictive one to determine the desired rollback minimum version. The blocks are also allowed to be erased (full of 1's), in which case the rollback minimum version is assumed to be 0. We also add an FMAP entry, in case we later decide to allow the signer to increment the rollback version. Also note that, like any version_data struct change, this change breaks compatibility between old and new RO/RW. Follow-up code will take care of auto-updating the rollback block as required, and properly manage block protection. BRANCH=none BUG=b:35586219 TEST=Flash hammer rollbackinfo => 1 version 0 block, 1 empty block, RW verifies correctly. rollbackupdate 0; rollbackinfo => No change rollbackupdate 1; reboot => RO refuses to jump to RW rollbackupdate 2, 3, 4; rollbackinfo => Writes alternate between the 2 blocks. rollbackupdate 2 => Refuses to downgrade version Change-Id: Ia969afb481a93deb912b9153bdd95ace01ad8fa7 Reviewed-on: https://chromium-review.googlesource.com/452815 Commit-Ready: Nicolas Boichat <drinkcat@chromium.org> Tested-by: Nicolas Boichat <drinkcat@chromium.org> Reviewed-by: Randall Spangler <rspangler@chromium.org> Reviewed-by: Vincent Palatin <vpalatin@chromium.org>