]> Pileus Git - ~andy/linux/blobdiff - kernel/audit.c
audit: audit feature to only allow unsetting the loginuid
[~andy/linux] / kernel / audit.c
index 91e53d04b6a9e8841e697dcb290f1206468da21a..fbfa3a74decb43820ee67b2e127c0256d8b5c62a 100644 (file)
@@ -60,7 +60,6 @@
 #ifdef CONFIG_SECURITY
 #include <linux/security.h>
 #endif
-#include <net/netlink.h>
 #include <linux/freezer.h>
 #include <linux/tty.h>
 #include <linux/pid_namespace.h>
@@ -140,6 +139,16 @@ static struct task_struct *kauditd_task;
 static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
 static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
 
+static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
+                                  .mask = -1,
+                                  .features = 0,
+                                  .lock = 0,};
+
+static char *audit_feature_names[1] = {
+       "only_unset_loginuid",
+};
+
+
 /* Serialize requests from userspace. */
 DEFINE_MUTEX(audit_cmd_mutex);
 
@@ -584,6 +593,8 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
                return -EOPNOTSUPP;
        case AUDIT_GET:
        case AUDIT_SET:
+       case AUDIT_GET_FEATURE:
+       case AUDIT_SET_FEATURE:
        case AUDIT_LIST_RULES:
        case AUDIT_ADD_RULE:
        case AUDIT_DEL_RULE:
@@ -613,7 +624,7 @@ static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
        int rc = 0;
        uid_t uid = from_kuid(&init_user_ns, current_uid());
 
-       if (!audit_enabled) {
+       if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
                *ab = NULL;
                return rc;
        }
@@ -628,6 +639,94 @@ static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
        return rc;
 }
 
+int is_audit_feature_set(int i)
+{
+       return af.features & AUDIT_FEATURE_TO_MASK(i);
+}
+
+
+static int audit_get_feature(struct sk_buff *skb)
+{
+       u32 seq;
+
+       seq = nlmsg_hdr(skb)->nlmsg_seq;
+
+       audit_send_reply(NETLINK_CB(skb).portid, seq, AUDIT_GET, 0, 0,
+                        &af, sizeof(af));
+
+       return 0;
+}
+
+static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
+                                    u32 old_lock, u32 new_lock, int res)
+{
+       struct audit_buffer *ab;
+
+       ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE);
+       audit_log_format(ab, "feature=%s new=%d old=%d old_lock=%d new_lock=%d res=%d",
+                        audit_feature_names[which], !!old_feature, !!new_feature,
+                        !!old_lock, !!new_lock, res);
+       audit_log_end(ab);
+}
+
+static int audit_set_feature(struct sk_buff *skb)
+{
+       struct audit_features *uaf;
+       int i;
+
+       BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > sizeof(audit_feature_names)/sizeof(audit_feature_names[0]));
+       uaf = nlmsg_data(nlmsg_hdr(skb));
+
+       /* if there is ever a version 2 we should handle that here */
+
+       for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
+               u32 feature = AUDIT_FEATURE_TO_MASK(i);
+               u32 old_feature, new_feature, old_lock, new_lock;
+
+               /* if we are not changing this feature, move along */
+               if (!(feature & uaf->mask))
+                       continue;
+
+               old_feature = af.features & feature;
+               new_feature = uaf->features & feature;
+               new_lock = (uaf->lock | af.lock) & feature;
+               old_lock = af.lock & feature;
+
+               /* are we changing a locked feature? */
+               if ((af.lock & feature) && (new_feature != old_feature)) {
+                       audit_log_feature_change(i, old_feature, new_feature,
+                                                old_lock, new_lock, 0);
+                       return -EPERM;
+               }
+       }
+       /* nothing invalid, do the changes */
+       for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
+               u32 feature = AUDIT_FEATURE_TO_MASK(i);
+               u32 old_feature, new_feature, old_lock, new_lock;
+
+               /* if we are not changing this feature, move along */
+               if (!(feature & uaf->mask))
+                       continue;
+
+               old_feature = af.features & feature;
+               new_feature = uaf->features & feature;
+               old_lock = af.lock & feature;
+               new_lock = (uaf->lock | af.lock) & feature;
+
+               if (new_feature != old_feature)
+                       audit_log_feature_change(i, old_feature, new_feature,
+                                                old_lock, new_lock, 1);
+
+               if (new_feature)
+                       af.features |= feature;
+               else
+                       af.features &= ~feature;
+               af.lock |= new_lock;
+       }
+
+       return 0;
+}
+
 static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
        u32                     seq;
@@ -699,6 +798,16 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT)
                        err = audit_set_backlog_limit(status_get->backlog_limit);
                break;
+       case AUDIT_GET_FEATURE:
+               err = audit_get_feature(skb);
+               if (err)
+                       return err;
+               break;
+       case AUDIT_SET_FEATURE:
+               err = audit_set_feature(skb);
+               if (err)
+                       return err;
+               break;
        case AUDIT_USER:
        case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
        case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
@@ -715,7 +824,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                        }
                        audit_log_common_recv_msg(&ab, msg_type);
                        if (msg_type != AUDIT_USER_TTY)
-                               audit_log_format(ab, " msg='%.1024s'",
+                               audit_log_format(ab, " msg='%.*s'",
+                                                AUDIT_MESSAGE_TEXT_MAX,
                                                 (char *)data);
                        else {
                                int size;
@@ -1067,13 +1177,6 @@ static void wait_for_auditd(unsigned long sleep_time)
        remove_wait_queue(&audit_backlog_wait, &wait);
 }
 
-/* Obtain an audit buffer.  This routine does locking to obtain the
- * audit buffer, but then no locking is required for calls to
- * audit_log_*format.  If the tsk is a task that is currently in a
- * syscall, then the syscall is marked as auditable and an audit record
- * will be written at syscall exit.  If there is no associated task, tsk
- * should be NULL. */
-
 /**
  * audit_log_start - obtain an audit buffer
  * @ctx: audit_context (may be NULL)
@@ -1388,7 +1491,7 @@ void audit_log_session_info(struct audit_buffer *ab)
        u32 sessionid = audit_get_sessionid(current);
        uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
 
-       audit_log_format(ab, " auid=%u ses=%u\n", auid, sessionid);
+       audit_log_format(ab, " auid=%u ses=%u", auid, sessionid);
 }
 
 void audit_log_key(struct audit_buffer *ab, char *key)