Re: [PATCH ghak90 (was ghak32) V4 03/10] audit: log container info of syscalls

On 2018-10-24 16:55, Paul Moore wrote: > On Wed, Oct 24, 2018 at 11:15 AM Richard Guy Briggs > <rgb(a)redhat.com&gt; wrote: > > On 2018-10-19 19:16, Paul Moore wrote: > > > On Sun, Aug 5, 2018 at 4:32 AM Richard Guy Briggs > > > <rgb(a)redhat.com&gt; wrote: > > > > Create a new audit record AUDIT_CONTAINER to document the > > > > audit container identifier of a process if it is present. > > > > > > > > Called from audit_log_exit(), syscalls are covered. > > > > > > > > A sample raw event: > > > > type=SYSCALL msg=audit(1519924845.499:257): arch=c000003e > > > > syscall=257 success=yes exit=3 a0=ffffff9c a1=56374e1cef30 > > > > a2=241 a3=1b6 items=2 ppid=606 pid=635 auid=0 uid=0 gid=0 > > > > euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=3 > > > > comm="bash" exe="/usr/bin/bash" > > > > subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 > > > > key="tmpcontainerid" type=CWD msg=audit(1519924845.499:257): > > > > cwd="/root" type=PATH msg=audit(1519924845.499:257): item=0 > > > > name="/tmp/" inode=13863 dev=00:27 mode=041777 ouid=0 ogid=0 > > > > rdev=00:00 obj=system_u:object_r:tmp_t:s0 nametype= PARENT > > > > cap_fp=0000000000000000 cap_fi=0000000000000000 cap_fe=0 > > > > cap_fver=0 type=PATH msg=audit(1519924845.499:257): item=1 > > > > name="/tmp/tmpcontainerid" inode=17729 dev=00:27 mode=0100644 > > > > ouid=0 ogid=0 rdev=00:00 > > > > obj=unconfined_u:object_r:user_tmp_t:s0 nametype=CREATE > > > > cap_fp=0000000000000000 cap_fi=0000000000000000 cap_fe=0 > > > > cap_fver=0 type=PROCTITLE msg=audit(1519924845.499:257): > > > > proctitle=62617368002D6300736C65657020313B206563686F2074657374203E202F746D702F746D70636F6E7461696E65726964 > > > > type=CONTAINER msg=audit(1519924845.499:257): op=task > > > > contid=123458 > > > > > > > > See: https://github.com/linux-audit/audit-kernel/issues/90 > > > > See: https://github.com/linux-audit/audit-userspace/issues/51 > > > > See: https://github.com/linux-audit/audit-testsuite/issues/64 > > > > See: > > > > https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID > > > > Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com&gt; Acked-by: > > > > Serge Hallyn <serge(a)hallyn.com&gt; Acked-by: Steve Grubb > > > > <sgrubb(a)redhat.com&gt; --- > > > > include/linux/audit.h | 7 +++++++ > > > > include/uapi/linux/audit.h | 1 + > > > > kernel/audit.c | 24 ++++++++++++++++++++++++ > > > > kernel/auditsc.c | 3 +++ > > > > 4 files changed, 35 insertions(+) > > > > > > ... > > > > > > > @@ -2045,6 +2045,30 @@ void audit_log_session_info(struct > > > > audit_buffer *ab) audit_log_format(ab, " auid=%u ses=%u", > > > > auid, sessionid); } > > > > > > > > +/* > > > > + * audit_log_contid - report container info > > > > + * @tsk: task to be recorded > > > > + * @context: task or local context for record > > > > + * @op: contid string description > > > > + */ > > > > +int audit_log_contid(struct task_struct *tsk, > > > > + struct audit_context *context, > > > > char *op) +{ > > > > + struct audit_buffer *ab; > > > > + > > > > + if (!audit_contid_set(tsk)) > > > > + return 0; > > > > + /* Generate AUDIT_CONTAINER record with container ID > > > > */ > > > > + ab = audit_log_start(context, GFP_KERNEL, > > > > AUDIT_CONTAINER); > > > > + if (!ab) > > > > + return -ENOMEM; > > > > + audit_log_format(ab, "op=%s contid=%llu", > > > > + op, audit_get_contid(tsk)); > > > > + audit_log_end(ab); > > > > + return 0; > > > > +} > > > > +EXPORT_SYMBOL(audit_log_contid); > > > > > > As discussed in the previous iteration of the patch, I prefer > > > AUDIT_CONTAINER_ID here over AUDIT_CONTAINER. If you feel > > > strongly about keeping it as-is with AUDIT_CONTAINER I suppose > > > I could live with that, but it is isn't my first choice. > > > > I don't have a strong opinion on this one, mildly preferring the > > shorter one only because it is shorter. > > We already have multiple AUDIT_CONTAINER* record types, so it seems > as though we should use "AUDIT_CONTAINER" as a prefix of sorts, > rather than a type itself. I'm fine with that. I'd still like to hear Steve's input. He had stronger opinions than me.

> > > However, I do care about the "op" field in this record. It just > > > doesn't make any sense; the way you are using it it is more of a > > > context field than an operations field, and even then why is the > > > context important from a logging and/or security perspective? > > > Drop it please. > > > > I'll rename it to whatever you like. I'd suggest "ref=". The > > reason I think it is important is there are multiple sources that > > aren't always obvious from the other records to which it is > > associated. In the case of ptrace and signals, there can be many > > target tasks listed (OBJ_PID) with no other way to distinguish > > the matching audit container identifier records all for one > > event. This is in addition to the default syscall container > > identifier record. I'm not currently happy with the text content > > to link the two, but that should be solvable (most obvious is > > taret PID). Throwing away this information seems shortsighted. > > It would be helpful if you could generate real audit events > demonstrating the problems you are describing, as well as a more > standard syscall event, so we can discuss some possible solutions. If the auditted process is in a container and it ptraces or signals another process in a container, there will be two AUDIT_CONTAINER records for the same event that won't be identified as to which record belongs to which process or other record (SYSCALL vs 1+ OBJ_PID records). There could be many signals recorded, each with their own OBJ_PID record. The first is stored in the audit context and additional ones are stored in a chained struct that can accommodate 16 entries each. (See audit_signal_info(), __audit_ptrace().) (As a side note, on code inspection it appears that a signal target would get overwritten by a ptrace action if they were to happen in that order.) > paul moore - RGB -- Richard Guy Briggs <rgb(a)redhat.com&gt; Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635 -- Linux-audit mailing list Linux-audit(a)redhat.com https://www.redhat.com/mailman/listinfo/linux-audit