[PATCH v2 0/2] support to read and tune appraise mode in runtime

[Tianjia Zhang]

Support the read and write operations of ima_appraise by adding a
securifyfs file 'appraise_mode'.

In order to tune appraise mode in runtime, writing a PKCS#7 signature
corresponding the signed content is required. The content should be off,
enforce, log or fix. Given a simple way to archive this:

$ echo -n off > mode
$ openssl smime -sign -nocerts -noattr -binary \
    -in mode -inkey <system_trusted_key> \
    -signer <cert> -outform der -out mode.p7s
$ sudo cat mode.p7s \
    > /sys/kernel/security/ima/appraise_mode

Note that the signing key must be a trust key located in
system trusted keyring. So even the root privilege cannot
simply disable the enforcement.

---
v2 change: fix build error.

Tianjia Zhang (2):
  ima: support to read appraise mode
  ima: support to tune appraise mode in runtime

 security/integrity/ima/ima_fs.c | 140 +++++++++++++++++++++++++++++++-
 1 file changed, 139 insertions(+), 1 deletion(-)

-- 
2.17.1