Re: [RFC][PATCH] audit: log join and part events to the read-only multicast log socket

On Tue, 2014-10-07 at 14:23 -0400, Richard Guy Briggs wrote: > Log the event when a client attempts to connect to the netlink audit multicast > socket, requiring CAP_AUDIT_READ capability, binding to the AUDIT_NLGRP_READLOG > group. Log the disconnect too. > > Sample output: > time->Tue Oct 7 14:15:19 2014 > type=UNKNOWN[1348] msg=audit(1412705719.316:117): auid=0 uid=0 gid=0 ses=1 pid=3552 comm="audit-multicast" exe="/home/rgb/rgb/git/audit-multicast-listen/audit-multicast-listen" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 group=0 op=connect res=1 > > Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com&gt; > --- > For some reason unbind isn't being called on disconnect. I suspect missing > plumbing in netlink. Investigation needed... > > include/uapi/linux/audit.h | 1 + > kernel/audit.c | 46 ++++++++++++++++++++++++++++++++++++++++++- > 2 files changed, 45 insertions(+), 2 deletions(-) > > diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h > index 4d100c8..7fa6e8f 100644 > --- a/include/uapi/linux/audit.h > +++ b/include/uapi/linux/audit.h > @@ -110,6 +110,7 @@ > #define AUDIT_SECCOMP 1326 /* Secure Computing event */ > #define AUDIT_PROCTITLE 1327 /* Proctitle emit event */ > #define AUDIT_FEATURE_CHANGE 1328 /* audit log listing feature changes */ > +#define AUDIT_EVENT_LISTENER 1348 /* task joined multicast read socket */ > > #define AUDIT_AVC 1400 /* SE Linux avc denial or grant */ > #define AUDIT_SELINUX_ERR 1401 /* Internal SE Linux Errors */ > diff --git a/kernel/audit.c b/kernel/audit.c > index 53bb39b..74c81a7 100644 > --- a/kernel/audit.c > +++ b/kernel/audit.c > @@ -1108,13 +1108,54 @@ static void audit_receive(struct sk_buff *skb) > mutex_unlock(&audit_cmd_mutex); > } > > +static void audit_log_bind(int group, char *op, int err) > +{ > + struct audit_buffer *ab; > + char comm[sizeof(current->comm)]; > + struct mm_struct *mm = current->mm; > + > + ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_EVENT_LISTENER); > + if (!ab) > + return; > + > + audit_log_format(ab, "auid=%d", > + from_kuid(&init_user_ns, audit_get_loginuid(current))); > + audit_log_format(ab, " uid=%d", > + from_kuid(&init_user_ns, current_uid())); > + audit_log_format(ab, " gid=%d", > + from_kgid(&init_user_ns, current_gid())); > + audit_log_format(ab, " ses=%d", audit_get_sessionid(current)); > + audit_log_format(ab, " pid=%d", task_pid_nr(current)); > + audit_log_format(ab, " comm="); > + audit_log_untrustedstring(ab, get_task_comm(comm, current)); > + if (mm) { > + down_read(&mm->mmap_sem); > + if (mm->exe_file) > + audit_log_d_path(ab, " exe=", &mm->exe_file->f_path); > + up_read(&mm->mmap_sem); > + } else > + audit_log_format(ab, " exe=(null)"); > + audit_log_task_context(ab); /* subj= */ super crazy yuck. audit_log_task_info() ??

> + audit_log_format(ab, " group=%d", group); group seems like too easily confused a name.

> + audit_log_format(ab, " op=%s", op); > + audit_log_format(ab, " res=%d", !err); > + audit_log_end(ab); > +} > + > /* Run custom bind function on netlink socket group connect or bind requests. */ > static int audit_bind(int group) > { > + int err = 0; > + > if (!capable(CAP_AUDIT_READ)) > - return -EPERM; > + err = -EPERM; > + audit_log_bind(group, "connect", err); > + return err; > +} > > - return 0; > +static void audit_unbind(int group) > +{ > + audit_log_bind(group, "disconnect", 0); > } > > static int __net_init audit_net_init(struct net *net) > @@ -1124,6 +1165,7 @@ static int __net_init audit_net_init(struct net *net) > .bind = audit_bind, > .flags = NL_CFG_F_NONROOT_RECV, > .groups = AUDIT_NLGRP_MAX, > + .unbind = audit_unbind, > }; > > struct audit_net *aunet = net_generic(net, audit_net_id);