On 05/21/2018 12:58 PM, Steve Grubb wrote:
On Thursday, May 17, 2018 10:18:13 AM EDT Stefan Berger wrote:
audit_log_container_info() then releasing the local context. This
version of the record has additional concerns covered here:
https://github.com/linux-audit/audit-kernel/issues/52
Following the discussion there and the concern with breaking user space,
how can we split up the AUDIT_INTEGRITY_RULE that is used in
ima_audit_measurement() and ima_parse_rule(), without 'breaking user
space'?
A message produced by ima_parse_rule() looks like this here:
type=INTEGRITY_RULE msg=audit(1526566213.870:305): action="dont_measure"
fsmagic="0x9fa0" res=1
Why is action and fsmagic being logged as untrusted strings? Untrusted
strings are used when an unprivileged user can affect the contents of the
field such as creating a file with space or special characters in the name.
Also, subject and object information is missing. Who loaded this rule?
in contrast to that an INTEGRITY_PCR record type:
type=INTEGRITY_PCR msg=audit(1526566235.193:334): pid=1615 uid=0 auid=0
ses=2 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
op="invalid_pcr" cause="open_writers" comm="scp"
name="/var/log/audit/audit.log" dev="dm-0" ino=1962625 res=1
Why is op & cause being logged as an untrusted string? This also has
incomplete subject information.
It's calling audit_log_string() in both cases:
https://elixir.bootlin.com/linux/latest/source/security/integrity/integrity_audit.c#L48
Should some of the fields from INTEGRITY_PCR also appear in
INTEGRITY_RULE? If so, which ones?
pid, uid, auid, tty, session, subj, comm, exe, res. <- these are required to
be searchable
We could probably refactor the current integrity_audit_message() and have
ima_parse_rule() call into it to get those fields as well. I suppose adding
new fields to it wouldn't be considered breaking user space?
The audit user space utilities pretty much expects those fields in that order
for any IMA originating events. You can add things like op or cause before
We will call into audit_log_task, which will put the parameters into
correct order:
auid uid gid ses subj pid comm exe
https://elixir.bootlin.com/linux/latest/source/kernel/auditsc.c#L2433
that. The reason why you can do that is those additional fields are not
required to be searchable by common criteria.
-Steve
