Log information about programs connecting and disconnecting to the audit netlink multicast socket. This is needed so that during investigations a security officer can tell who or what had access to the audit trail. This helps to meet the FAU_SAR.2 requirement for Common Criteria. Signed-off-by: sgrubb <sgrubb(a)redhat.com&gt; --- include/uapi/linux/audit.h | 1 + kernel/audit.c | 31 +++++++++++++++++++++++++++---- 2 files changed, 28 insertions(+), 4 deletions(-) diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h index 82e8aa5..e6dd046 100644 --- a/include/uapi/linux/audit.h +++ b/include/uapi/linux/audit.h @@ -111,6 +111,7 @@ #define AUDIT_PROCTITLE 1327 /* Proctitle emit event */ #define AUDIT_FEATURE_CHANGE 1328 /* audit log listing feature changes */ #define AUDIT_REPLACE 1329 /* Replace auditd if this packet unanswerd */ +#define AUDIT_EVENT_LISTENER 1330 /* 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 22f8c3d..910a7c1 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -1161,22 +1161,45 @@ void audit_log_task_simple(struct audit_buffer *ab, struct task_struct *tsk) } EXPORT_SYMBOL(audit_log_task_simple); +/* Log information about who is connecting to the audit multicast socket */ +static void audit_log_multicast_bind(int group, const char *op, int err) +{ + struct audit_buffer *ab; + + ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_EVENT_LISTENER); + if (!ab) + return; + + audit_log_task_simple(ab, current); + audit_log_format(ab, " nlnk-grp=%d op=%s res=%d", group, op, !err); + audit_log_end(ab); +} + /* Run custom bind function on netlink socket group connect or bind requests. */ -static int audit_bind(struct net *net, int group) +static int audit_multicast_bind(struct net *net, int group) { + int err = 0; + if (!capable(CAP_AUDIT_READ)) - return -EPERM; + err = -EPERM; + audit_log_multicast_bind(group, "connect", err); - return 0; + return err; +} + +static void audit_multicast_unbind(struct net *net, int group) +{ + audit_log_multicast_bind(group, "disconnect", 0); } static int __net_init audit_net_init(struct net *net) { struct netlink_kernel_cfg cfg = { .input = audit_receive, - .bind = audit_bind, + .bind = audit_multicast_bind, .flags = NL_CFG_F_NONROOT_RECV, .groups = AUDIT_NLGRP_MAX, + .unbind = audit_multicast_unbind, }; struct audit_net *aunet = net_generic(net, audit_net_id); -- 2.7.4