There are several kernel components that contain critical data which if accidentally or maliciously altered, can compromise the security of the kernel. Example of such components would include LSMs like SELinux, or AppArmor; or device-mapper targets like dm-crypt, dm-verity etc. Many of these components do not use the capabilities provided by kernel integrity subsystem (IMA), and thus they don't use the benefits of extended TPM PCR quotes and ultimately the benefits of remote attestation. This series bridges this gap, so that potential kernel components that contain data critical to the security of the kernel could take advantage of IMA's measuring and quoting abilities - thus ultimately enabling remote attestation for their specific data. System administrators may want to pick and choose which kernel components they would want to enable for measurements, quoting, and remote attestation. To enable that, a new IMA policy is introduced. And lastly, the functionality is exposed through a function ima_measure_critical_data(). The functionality is generic enough to measure the data of any kernel component at run-time. To ensure that only data from supported sources are measured, the kernel component needs to be added to a compile-time list of supported sources (an "allowed list of components"). IMA validates the source passed to ima_measure_critical_data() against this allowed list at run-time. This series is based on the following repo/branch: repo: https://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git branch: next-integrity commit aa662fc04f5b ("ima: Fix NULL pointer dereference in ima_file_hash") Change Log v4: Incorporated feedback from Mimi on v3. - Split patch #1 into two patches to move introduction of bool allow_empty_opt_list into the 2nd patch. - Reverted return type of process_buffer_measurement() from int to void which got rid of patch #2 from the v3 of the series. - Renamed the policy "critical_kernel_data_sources" to "data_sources". - Updated process_buffer_measurement() to avoid code and variable duplication in the if(measure_buf_hash) block. - Changed return type of ima_measure_critical_data() from int to void. - Updated patch description for patch #3 and #4 as per Mimi's feedback. Change Log v3: Incorporated feedback from Mimi on v2. - Renamed the policy "data_sources" to "critical_kernel_data_sources". - Added "critical_kernel_data_sources" description in Documentation/ima-policy. - Split CRITICAL_DATA + critical_kernel_data_sources into two separate patches. - Merged hook ima_measure_critical_data() + CRITICAL_DATA into a single patch. - Added functionality to validate data sources before measurement. Change Log v2: - Reverted the unnecessary indentations in existing #define. - Updated the description to replace the word 'enlightened' with 'supported'. - Reverted the unnecessary rename of attribute size to buf_len. - Introduced a boolean parameter measure_buf_hash as per community feedback to support measuring hash of the buffer, instead of the buffer itself. Tushar Sugandhi (6): IMA: generalize keyring specific measurement constructs IMA: conditionally allow empty rule data IMA: update process_buffer_measurement to measure buffer hash IMA: add policy to measure critical data from kernel components IMA: add hook to measure critical data from kernel components IMA: validate supported kernel data sources before measurement Documentation/ABI/testing/ima_policy | 11 +- include/linux/ima.h | 8 ++ security/integrity/ima/ima.h | 37 ++++++- 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 | 61 ++++++++++- security/integrity/ima/ima_policy.c | 101 +++++++++++++++---- security/integrity/ima/ima_queue_keys.c | 3 +- 9 files changed, 196 insertions(+), 37 deletions(-) -- 2.17.1
