Kernel integrity critical data can be defined as the in-memory kernel data which if accidentally or maliciously altered, can compromise the integrity of the system. There are several kernel subsystems that contain integrity critical data - e.g. LSMs like SELinux, or AppArmor; or device-mapper targets like dm-crypt, dm-verity etc. Examples of critical data could be kernel in-memory r/o structures, hash of the memory structures, or data that represents a linux kernel subsystem state. This patch set defines a new IMA hook namely ima_measure_critical_data() to measure the critical data. Kernel subsystems can use this functionality, to take advantage of IMA's measuring and quoting abilities - thus ultimately enabling remote attestation for the subsystem specific information stored in the kernel memory. The functionality is generic enough to measure the data, from the kernel subsystems, that is required to protect the integrity of the kernel at runtime. System administrators may want to limit the critical data being measured, quoted, and attested. To enable that, a new IMA policy condition is defined. This patch set also addresses the need for measuring kernel critical data early, before a custom IMA policy is loaded - by providing a builtin IMA policy. And lastly, the series provides the first consumer of the new IMA hook - namely SeLinux. This series is based on the following repo/branch: repo: https://github.com/torvalds/linux branch: master commit 09162bc32c88 ("Linux 5.10-rc4") This series also has a dependency on the following patch https://patchwork.kernel.org/patch/11901423/ Change Log v6: Incorporated feedback from Mimi on v5 of this series. - Got rid of patch 5 from the v5 of the series.(the allow list for data sources) - Updated function descriptions, changed variable names etc. - Moved the input param event_data_source in ima_measure_critical_data() to a new patch. (patch 6/8 of this series) - Split patch 4 from v5 of the series into two patches (patch 4/8 and patch 5/8) - Updated cover letter and patch descriptions as per feedback. Change Log v5: (1) Incorporated feedback from Stephen on the last SeLinux patch. SeLinux Patch: https://patchwork.kernel.org/patch/11801585/ - Freed memory in the reverse order of allocation in selinux_measure_state(). - Used scnprintf() instead of snprintf() to create the string for selinux state. - Allocated event name passed to ima_measure_critical_data() before gathering selinux state and policy information for measuring. (2) Incorporated feedback from Mimi on v4 of this series. V4 of this Series: https://patchwork.kernel.org/project/linux-integrity/list/?series=354437 - Removed patch "[v4,2/6] IMA: conditionally allow empty rule data" - Reversed the order of following patches. [v4,4/6] IMA: add policy to measure critical data from kernel components [v4,5/6] IMA: add hook to measure critical data from kernel components and renamed them to remove "from kernel components" - Added a new patch to this series - IMA: add critical_data to built-in policy rules - Added the next version of SeLinux patch (mentioned above) to this series selinux: measure state and hash of the policy using IMA - Updated cover-letter description to give broader perspective of the feature, rearranging paragraphs, removing unnecessary info, clarifying terms etc. - Got rid of opt_list param from ima_match_rule_data(). - Updated the documentation to remove sources that don't yet exist. - detailed IMA hook description added to ima_measure_critical_data(), as well as elaborating terms event_name, event_data_source. - "data_sources:=" is not a mandatory policy option for func=CRITICAL_DATA anymore. If not present, all the data sources specified in __ima_supported_kernel_data_sources will be measured. Lakshmi Ramasubramanian (2): IMA: add a built-in policy rule for critical data measurement selinux: measure state and hash of the policy using IMA Tushar Sugandhi (6): IMA: generalize keyring specific measurement constructs IMA: add support to measure buffer data hash IMA: define a hook to measure kernel integrity critical data IMA: add policy rule to measure critical data IMA: extend policy to add data sources as a critical data measurement constraint IMA: add support to critical data hook to limit data sources for measurement Documentation/ABI/testing/ima_policy | 10 +- include/linux/ima.h | 8 + security/integrity/ima/ima.h | 8 +- security/integrity/ima/ima_api.c | 8 +- security/integrity/ima/ima_appraise.c | 2 +- security/integrity/ima/ima_asymmetric_keys.c | 2 +- security/integrity/ima/ima_main.c | 81 +++++++++- security/integrity/ima/ima_policy.c | 123 ++++++++++++--- security/integrity/ima/ima_queue_keys.c | 3 +- security/selinux/Makefile | 2 + security/selinux/hooks.c | 3 + security/selinux/include/security.h | 11 +- security/selinux/measure.c | 157 +++++++++++++++++++ security/selinux/selinuxfs.c | 8 + security/selinux/ss/services.c | 71 +++++++-- 15 files changed, 448 insertions(+), 49 deletions(-) create mode 100644 security/selinux/measure.c -- 2.17.1
