[PATCH] Rework of IPC auditing

1) The audit_ipc_perms() function has been split into two different
functions:
        - audit_ipc_obj()
        - audit_ipc_set_perm()

There's a key shift here...  The audit_ipc_obj() collects the uid, gid,
mode, and SElinux context label of the current ipc object.  This
audit_ipc_obj() hook is now found in several places.  Most notably, it
is hooked in ipcperms(), which is called in various places around the
ipc code permforming a MAC check.  Additionally there are several places
where *checkid() is used to validate that an operation is being
performed on a valid object while not necessarily having a nearby
ipcperms() call.  In these locations, audit_ipc_obj() is called to
ensure that the information is captured by the audit system.

The audit_set_new_perm() function is called any time the permissions on
the ipc object changes.  In this case, the NEW permissions are recorded
(and note that an audit_ipc_obj() call exists just a few lines before
each instance).

2) Support for an AUDIT_IPC_SET_PERM audit message type.  This allows
for separate auxiliary audit records for normal operations on an IPC
object and permissions changes.  Note that the same struct
audit_aux_data_ipcctl is used and populated, however there are separate
audit_log_format statements based on the type of the message.  Finally,
the AUDIT_IPC block of code in audit_free_aux() was extended to handle
aux messages of this new type.  No more mem leaks I hope ;-)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 10 insertions, 1 deletions

diff --git a/ipc/sem.c b/ipc/sem.c
index 642659cd596b..7919f8ece6ba 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -61,6 +61,9 @@
  * (c) 2001 Red Hat Inc <alan@redhat.com>
  * Lockless wakeup
  * (c) 2003 Manfred Spraul <manfred@colorfullife.com>
+ *
+ * support for audit of ipc object properties and permission changes
+ * Dustin Kirkland <dustin.kirkland@us.ibm.com>
  */
 
 #include <linux/config.h>
@@ -820,6 +823,11 @@ static int semctl_down(int semid, int semnum, int cmd, int version, union semun
                 goto out_unlock;
         }       
         ipcp = &sma->sem_perm;
+
+        err = audit_ipc_obj(ipcp);
+        if (err)
+                goto out_unlock;
+
         if (current->euid != ipcp->cuid && 
             current->euid != ipcp->uid && !capable(CAP_SYS_ADMIN)) {
                 err=-EPERM;
@@ -836,7 +844,8 @@ static int semctl_down(int semid, int semnum, int cmd, int version, union semun
                 err = 0;
                 break;
         case IPC_SET:
-                if ((err = audit_ipc_perms(0, setbuf.uid, setbuf.gid, setbuf.mode, ipcp)))
+                err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode, ipcp);
+                if (err)
                         goto out_unlock;
                 ipcp->uid = setbuf.uid;
                 ipcp->gid = setbuf.gid;