[PATCH ghau90 v1] sig_info: use standard template for log messages
Steve Grubb
sgrubb at redhat.com
Mon Apr 15 21:10:37 UTC 2019
On Monday, April 15, 2019 12:21:49 PM EDT Richard Guy Briggs wrote:
> On 2019-04-15 10:58, Steve Grubb wrote:
> > On Monday, April 15, 2019 9:02:36 AM EDT Richard Guy Briggs wrote:
> > > Records that are triggered by an AUDIT_SIGNAL_INFO message including
> > > AUDIT_DAEMON_CONFIG (HUP), AUDIT_DAEMON_ROTATE (USR1),
> > > AUDIT_DAEMON_RESUME (USR2) and AUDIT_DAEMON_END (TERM) have
> > > inconsistent reporting of signal info and swinging field "state".
> >
> > This is crusty old code that has things in it that were for migrations
> > with very old kernels. It's not readily obvious because those kernel
> > transitions were quite some time ago. There was also a fake
> >
> > > They also assume that an empty security context implies there is no
> > > other useful information in the AUDIT_SIGNAL_INFO message so don't use
> > > the information that is there.
> >
> > How are you generating the events that trigger this? If this is based on
> > reading the source code, I think its because of an ancient kernel change.
> > If you can generate this condition, then I'd like to replicate the
> > problem on my system to see what's happening.
>
> I used a current audit/next kernel, compiled with AUDIT_CONFIG, but with
> and without AUDIT_CONFIGSYSCALL
Is this a configuration that we really want to support? :-) This really will
not work as anything except for gathering AVC's or other LSM events. And I
think those go to syslog anyways. I'd say that with this kernel configuration,
they likely would not run auditd as there's no point in it.
> and simply signalled the audit daemon with the four signals and then ran
> ausearch on the most recent messages.
>
> I did not generate errors, but I could have by creating a custom kernel
> that returned errors upon request for AUDIT_SIGNAL_INFO.
>
> > > Normalize AUDIT_DAEMON_CONFIG to use the value "reconfigure" and add
> > > the "state" field where missing.
> > >
> > > Use audit_sig_info values when available, not making assumptions about
> > > their availability when the security context is absent.
> > >
> > > See: https://github.com/linux-audit/audit-userspace/issues/90
> >
> > I had made changes to the git repo Saturday. I suspect this patch does
> > not apply. I like the op value changes. That part I can go along with.
> > Shall I just make that adjustment in the upstream repo and we can talk
> > more about how you are creating these events?
>
> This patch was rebased on your patch so it is current.
One thing I should mention, the audit events are created with and without the
subj field because for common criteria, a DAC based system should have no
notion of MAC fields. This is why we alway branch on the "ctx" variables and
create the event with or without subj.
> I wanted it all in one function so that the format was consistent rather
> than open coded for anything that could use the AUDIT_SIGNAL_INFO
> contents. This will also help once there is also a cid (contid) to
> report.
OK.
-Steve
> > > Signed-off-by: Richard Guy Briggs <rgb at redhat.com>
> > > ---
> > >
> > > docs/audit_request_signal_info.3 | 2 +-
> > > lib/libaudit.c | 12 +++++++++
> > > lib/libaudit.h | 1 +
> > > src/auditd-reconfig.c | 9 +++----
> > > src/auditd.c | 54
> > >
> > > ++++++++++++++-------------------------- 5 files changed, 36
> > > insertions(+), 42 deletions(-)
> > >
> > > diff --git a/docs/audit_request_signal_info.3
> > > b/docs/audit_request_signal_info.3 index 873deb58bef3..b68d7bbefeed
> > > 100644
> > > --- a/docs/audit_request_signal_info.3
> > > +++ b/docs/audit_request_signal_info.3
> > > @@ -8,7 +8,7 @@ int audit_request_signal_info(int fd);
> > >
> > > .SH "DESCRIPTION"
> > >
> > > -audit_request_signal_info requests that the kernel send information
> > > about
> > > the sender of a signal to the audit daemon. The sinal info structure is
> > > as
> > > follows: +audit_request_signal_info requests that the kernel send
> > > information about the sender of a signal to the audit daemon. The
> > > signal
> > >
> > > info structure is as follows:
> > > .nf
> > > struct audit_sig_info {
> > >
> > > diff --git a/lib/libaudit.c b/lib/libaudit.c
> > > index 2af017a0e520..e9c4f9cad6df 100644
> > > --- a/lib/libaudit.c
> > > +++ b/lib/libaudit.c
> > > @@ -674,6 +674,18 @@ int audit_request_signal_info(int fd)
> > >
> > > return rc;
> > >
> > > }
> > >
> > > +char *audit_format_signal_info(char *buf, int len, char *op, struct
> > > audit_reply *rep, char *res) +{
> > > + snprintf(buf, len,
> > > + "op=%s auid=%u pid=%d subj=%s res=%s",
> > > + op,
> > > + rep->signal_info->uid,
> > > + rep->signal_info->pid,
> > > + rep->len == 24 ? "?" : rep->signal_info->ctx,
> > > + res);
> > > + return buf;
> > > +}
> > > +
> > >
> > > int audit_update_watch_perms(struct audit_rule_data *rule, int perms)
> > > {
> > >
> > > unsigned int i, done=0;
> > >
> > > diff --git a/lib/libaudit.h b/lib/libaudit.h
> > > index ca7aa63e354e..63a5e948d00e 100644
> > > --- a/lib/libaudit.h
> > > +++ b/lib/libaudit.h
> > > @@ -562,6 +562,7 @@ extern int audit_setloginuid(uid_t uid);
> > >
> > > extern uint32_t audit_get_session(void);
> > > extern int audit_detect_machine(void);
> > > extern int audit_determine_machine(const char *arch);
> > >
> > > +extern char *audit_format_signal_info(char *buf, int len, char *op,
> > > struct audit_reply *rep, char *res);
> > >
> > > /* Translation functions */
> > > extern int audit_name_to_field(const char *field);
> > >
> > > diff --git a/src/auditd-reconfig.c b/src/auditd-reconfig.c
> > > index a03e29aa57ab..f5b00e6d1dc7 100644
> > > --- a/src/auditd-reconfig.c
> > > +++ b/src/auditd-reconfig.c
> > > @@ -115,12 +115,9 @@ static void *config_thread_main(void *arg)
> > >
> > > } else {
> > >
> > > // need to send a failed event message
> > > char txt[MAX_AUDIT_MESSAGE_LENGTH];
> > >
> > > - snprintf(txt, sizeof(txt),
> > > - "op=reconfigure state=no-change auid=%u pid=%d subj=%s
> >
> > res=failed",
> >
> > > - e->reply.signal_info->uid,
> > > - e->reply.signal_info->pid,
> > > - (e->reply.len > 24) ?
> > > - e->reply.signal_info->ctx : "?");
> > > + audit_format_signal_info(txt, sizeof(txt),
> > > + "reconfigure state=no-change",
> > > + &e->reply, "failed");
> > >
> > > // FIXME: need to figure out sending this
> > > //send_audit_event(AUDIT_DAEMON_CONFIG, txt);
> > > free_config(&new_config);
> > >
> > > diff --git a/src/auditd.c b/src/auditd.c
> > > index c04a1c9ce93f..5c31583a49c6 100644
> > > --- a/src/auditd.c
> > > +++ b/src/auditd.c
> > > @@ -131,7 +131,7 @@ static void hup_handler( struct ev_loop *loop,
> > > struct
> > > ev_signal *sig, int revent rc = audit_request_signal_info(fd);
> > >
> > > if (rc < 0)
> > >
> > > send_audit_event(AUDIT_DAEMON_CONFIG,
> > >
> > > - "op=hup-info state=request-siginfo auid=-1 pid=-1 subj=?
> >
> > res=failed");
> >
> > > + "op=reconfigure state=no-change auid=-1 pid=-1 subj=? res=failed");
> > >
> > > else
> > >
> > > hup_info_requested = 1;
> > >
> > > }
> > >
> > > @@ -147,7 +147,7 @@ static void user1_handler(struct ev_loop *loop,
> > > struct
> > > ev_signal *sig, rc = audit_request_signal_info(fd);
> > >
> > > if (rc < 0)
> > >
> > > send_audit_event(AUDIT_DAEMON_ROTATE,
> > >
> > > - "op=usr1-info auid=-1 pid=-1 subj=? res=failed");
> > > + "op=rotate-logs auid=-1 pid=-1 subj=? res=failed");
> > >
> > > else
> > >
> > > usr1_info_requested = 1;
> > >
> > > }
> > >
> > > @@ -163,7 +163,7 @@ static void user2_handler( struct ev_loop *loop,
> > > struct ev_signal *sig, int reve if (rc < 0) {
> > >
> > > resume_logging();
> > > send_audit_event(AUDIT_DAEMON_RESUME,
> > >
> > > - "op=resume-logging auid=-1 pid=-1 subj=?
> >
> > res=success");
> >
> > > + "op=resume-logging auid=-1 pid=-1 subj=?
res=failed");
> > >
> > > } else
> > >
> > > usr2_info_requested = 1;
> > >
> > > }
> > >
> > > @@ -515,45 +515,33 @@ static void netlink_handler(struct ev_loop *loop,
> > > struct ev_io *io, break;
> > >
> > > case AUDIT_SIGNAL_INFO:
> > > if (hup_info_requested) {
> > >
> > > + char hup[MAX_AUDIT_MESSAGE_LENGTH];
> > >
> > > audit_msg(LOG_DEBUG,
> > >
> > > "HUP detected, starting config manager");
> > >
> > > reconfig_ev = cur_event;
> > > if (start_config_manager(cur_event)) {
> > >
> > > - send_audit_event(
> > > - AUDIT_DAEMON_CONFIG,
> > > - "op=reconfigure state=no-change "
> > > - "auid=-1 pid=-1 subj=? res=failed");
> > > + audit_format_signal_info(hup,
sizeof(hup),
> > > + "reconfigure
> >
> > state=no-change",
> >
> > > + &cur_event->reply,
> > > + "failed");
> > > + send_audit_event(AUDIT_DAEMON_CONFIG,
> >
> > hup);
> >
> > > }
> > > cur_event = NULL;
> > > hup_info_requested = 0;
> > >
> > > } else if (usr1_info_requested) {
> > >
> > > char usr1[MAX_AUDIT_MESSAGE_LENGTH];
> > >
> > > - if (cur_event->reply.len == 24) {
> > > - snprintf(usr1, sizeof(usr1),
> > > - "op=rotate-logs auid=-1 pid=-1 subj=?");
> > > - } else {
> > > - snprintf(usr1, sizeof(usr1),
> > > - "op=rotate-logs auid=%u pid=%d subj=%s",
> > > - cur_event->reply.signal_info->uid,
> > > - cur_event->reply.signal_info->pid,
> > > - cur_event->reply.signal_info->ctx);
> > > - }
> > > + audit_format_signal_info(usr1, sizeof(usr1),
> > > + "rotate-logs",
> > > + &cur_event->reply,
> > > + "success");
> > >
> > > send_audit_event(AUDIT_DAEMON_ROTATE, usr1);
> > > usr1_info_requested = 0;
> > >
> > > } else if (usr2_info_requested) {
> > >
> > > char usr2[MAX_AUDIT_MESSAGE_LENGTH];
> > >
> > > - if (cur_event->reply.len == 24) {
> > > - snprintf(usr2, sizeof(usr2),
> > > - "op=resume-logging auid=-1 "
> > > - "pid=-1 subj=? res=success");
> > > - } else {
> > > - snprintf(usr2, sizeof(usr2),
> > > - "op=resume-logging "
> > > - "auid=%u pid=%d subj=%s res=success",
> > > - cur_event->reply.signal_info->uid,
> > > - cur_event->reply.signal_info->pid,
> > > - cur_event->reply.signal_info->ctx);
> > > - }
> > > + audit_format_signal_info(usr2, sizeof(usr2),
> > > + "resume-logging",
> > > + &cur_event->reply,
> > > + "success");
> > >
> > > resume_logging();
> > > libdisp_resume();
> > > send_audit_event(AUDIT_DAEMON_RESUME, usr2);
> > >
> > > @@ -993,12 +981,8 @@ int main(int argc, char *argv[])
> > >
> > > rc = get_reply(fd, &trep, rc);
> > > if (rc > 0) {
> > >
> > > char txt[MAX_AUDIT_MESSAGE_LENGTH];
> > >
> > > - snprintf(txt, sizeof(txt),
> > > - "op=terminate auid=%u "
> > > - "pid=%d subj=%s res=success",
> > > - trep.signal_info->uid,
> > > - trep.signal_info->pid,
> > > - trep.signal_info->ctx);
> > > + audit_format_signal_info(txt, sizeof(txt),
"terminate",
> > > + &trep, "success");
> > >
> > > send_audit_event(AUDIT_DAEMON_END, txt);
> > >
> > > }
> > >
> > > }
> >
> > --
> > Linux-audit mailing list
> > Linux-audit at redhat.com
> > https://www.redhat.com/mailman/listinfo/linux-audit
>
> - RGB
>
> --
> Richard Guy Briggs <rgb at redhat.com>
> 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
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