Re: [PATCH v17 20/23] Audit: Add a new record for multiple subject LSM attributes
On Thu, May 14, 2020 at 7:30 PM Casey Schaufler <casey(a)schaufler-ca.com> wrote:
Create a new audit record type to contain the subject information
when there are multiple security modules that require such data.
This record is emitted before the other records for the event, but
is linked with the same timestamp and serial number.
Reviewed-by: Kees Cook <keescook(a)chromium.org>
Signed-off-by: Casey Schaufler <casey(a)schaufler-ca.com>
Cc: linux-audit(a)redhat.com
---
With this patch, I see userspace audit records like this one:
type=SYSTEM_BOOT msg=audit(1589816792.181:103): pid=789 uid=0
auid=4294967295 ses=4294967295 subj=? subj=system_u:system_r:init_t:s0
msg=' comm="systemd-update-utmp"
exe="/usr/lib/systemd/systemd-update-utmp" hostname=? addr=?
terminal=? res=success'
I'm guessing that userspace is appending the second subj= field when
it sees subj=? or otherwise is missing subj= information?
Then we have kernel audit records like this:
type=PROCTITLE msg=audit(1589816791.959:101): proctitle=2F7362696E2F617564697463
746C002D52002F6574632F61756469742F61756469742E72756C6573
type=SYSCALL msg=audit(1589816791.959:101): arch=c000003e syscall=44
success=yes exit=1056 a0=3 a1=7fff9ccc98a0 a2=420 a3=0 items=0
ppid=773 pid=783 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0
egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="auditctl"
exe="/usr/sbin/auditctl" subj=? key=(null)
type=UNKNOWN[1420] msg=audit(1589816791.959:101):
subj_selinux=system_u:system_r:unconfined_service_t:s0
subj_apparmor==unconfined
type=CONFIG_CHANGE msg=audit(1589816791.959:101): auid=4294967295
ses=4294967295 subj=? op=add_rule key=(null) list=1 res=1
type=UNKNOWN[1420] msg=audit(1589816791.959:101):
subj_selinux=system_u:system_r:unconfined_service_t:s0
subj_apparmor==unconfined
where we are getting multiple copies of the new record type, one for
each record type that had subj=?.
Not sure what it is the audit folks want here.
This is with multiple LSMs enabled; need to confirm that no change
occurs if only one is enabled.