[v4,0/3] ima: Provide more info about buffer measurement

Message

Roberto Sassu July 23, 2021, 8:53 a.m. UTC

This patch set provides more information about buffer measurement. It
requires the modification of the existing functions
ima_measure_critical_data() and process_buffer_measurement() as, unlike
for files, there is no integrity_iint_cache structure that can be used to
store and retrieve at a later time the buffer measurement (there is no
index, for files it is the inode number).

First, this patch set introduces the new function
ima_get_current_hash_algo(), to obtain the algorithm used to calculate the
buffer digest (patch 1).

Second, it changes the type of return value of ima_measure_critical_data()
and process_buffer_measurement() from void to int, to signal to the callers
whether or not the buffer has been measured, or just the digest has been
calculated and written to the supplied location (patch 2).

Lastly, it adds two new parameters to the functions above ('digest' and
'digest_len'), so that those functions can write the buffer digest to the
location supplied by the callers (patch 3).

This patch set replaces the patch 'ima: Add digest, algo, measured
parameters to ima_measure_critical_data()' in:

https://lore.kernel.org/linux-integrity/[e-mail]/

Changelog

v3:
- explain better the motivation for the patches (suggested by Mimi)

v2:
- remove assignments of ima_measure_critical_data() and
  process_buffer_measurement() return values (suggested by Lakshmi)

v1:
- add digest_len parameter to ima_measure_critical_data() and
  process_buffer_measurement() (suggested by Lakshmi)
- fix doc formatting issues

Huawei Digest Lists patch set:
- introduce ima_get_current_hash_algo() (suggested by Mimi)
- remove algo and measured parameters from ima_measure_critical_data() and
  process_buffer_measurement() (suggested by Mimi)
- return an integer from ima_measure_critical_data() and
  process_buffer_measurement() (suggested by Mimi)
- correctly check when process_buffer_measurement() should return earlier

Roberto Sassu (3):
  ima: Introduce ima_get_current_hash_algo()
  ima: Return int in the functions to measure a buffer
  ima: Add digest and digest_len params to the functions to measure a
    buffer

 include/linux/ima.h                          | 23 +++++--
 security/integrity/ima/ima.h                 | 10 +--
 security/integrity/ima/ima_appraise.c        |  2 +-
 security/integrity/ima/ima_asymmetric_keys.c |  2 +-
 security/integrity/ima/ima_init.c            |  3 +-
 security/integrity/ima/ima_main.c            | 67 ++++++++++++++------
 security/integrity/ima/ima_queue_keys.c      |  2 +-
 security/selinux/ima.c                       |  6 +-
 8 files changed, 78 insertions(+), 37 deletions(-)