[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>

4 files changed, 42 insertions, 6 deletions

diff --git a/ipc/msg.c b/ipc/msg.c
index 48a7f17..7d1340c 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -13,6 +13,9 @@
  * mostly rewritten, threaded and wake-one semantics added
  * MSGMAX limit removed, sysctl's added
  * (c) 1999 Manfred Spraul <manfred@colorfullife.com>
+ *
+ * support for audit of ipc object properties and permission changes
+ * Dustin Kirkland <dustin.kirkland@us.ibm.com>
  */
 
 #include <linux/capability.h>
@@ -447,6 +450,11 @@ asmlinkage long sys_msgctl (int msqid, int cmd, struct msqid_ds __user *buf)
 	if (msg_checkid(msq,msqid))
 		goto out_unlock_up;
 	ipcp = &msq->q_perm;
+
+	err = audit_ipc_obj(ipcp);
+	if (err)
+		goto out_unlock_up;
+
 	err = -EPERM;
 	if (current->euid != ipcp->cuid && 
 	    current->euid != ipcp->uid && !capable(CAP_SYS_ADMIN))
@@ -460,7 +468,8 @@ asmlinkage long sys_msgctl (int msqid, int cmd, struct msqid_ds __user *buf)
 	switch (cmd) {
 	case IPC_SET:
 	{
-		if ((err = audit_ipc_perms(setbuf.qbytes, setbuf.uid, setbuf.gid, setbuf.mode, ipcp)))
+		err = audit_ipc_set_perm(setbuf.qbytes, setbuf.uid, setbuf.gid, setbuf.mode, ipcp);
+		if (err)
 			goto out_unlock_up;
 
 		err = -EPERM;
diff --git a/ipc/sem.c b/ipc/sem.c
index 642659c..7919f8e 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;
diff --git a/ipc/shm.c b/ipc/shm.c
index 1c2faf6..8098968 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -13,6 +13,8 @@
  * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
  * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
  *
+ * support for audit of ipc object properties and permission changes
+ * Dustin Kirkland <dustin.kirkland@us.ibm.com>
  */
 
 #include <linux/config.h>
@@ -542,6 +544,10 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
 		if(err)
 			goto out_unlock;
 
+		err = audit_ipc_obj(&(shp->shm_perm));
+		if (err)
+			goto out_unlock;
+
 		if (!capable(CAP_IPC_LOCK)) {
 			err = -EPERM;
 			if (current->euid != shp->shm_perm.uid &&
@@ -594,6 +600,10 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
 		if(err)
 			goto out_unlock_up;
 
+		err = audit_ipc_obj(&(shp->shm_perm));
+		if (err)
+			goto out_unlock_up;
+
 		if (current->euid != shp->shm_perm.uid &&
 		    current->euid != shp->shm_perm.cuid && 
 		    !capable(CAP_SYS_ADMIN)) {
@@ -627,12 +637,15 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
 		err=-EINVAL;
 		if(shp==NULL)
 			goto out_up;
-		if ((err = audit_ipc_perms(0, setbuf.uid, setbuf.gid,
-					setbuf.mode, &(shp->shm_perm))))
-			goto out_unlock_up;
 		err = shm_checkid(shp,shmid);
 		if(err)
 			goto out_unlock_up;
+		err = audit_ipc_obj(&(shp->shm_perm));
+		if (err)
+			goto out_unlock_up;
+		err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode, &(shp->shm_perm));
+		if (err)
+			goto out_unlock_up;
 		err=-EPERM;
 		if (current->euid != shp->shm_perm.uid &&
 		    current->euid != shp->shm_perm.cuid && 
diff --git a/ipc/util.c b/ipc/util.c
index b3dcfad..8193299 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -10,6 +10,8 @@
  *	      Manfred Spraul <manfred@colorfullife.com>
  * Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary().
  *            Mingming Cao <cmm@us.ibm.com>
+ * Mar 2006 - support for audit of ipc object properties
+ *            Dustin Kirkland <dustin.kirkland@us.ibm.com>
  */
 
 #include <linux/config.h>
@@ -27,6 +29,7 @@
 #include <linux/workqueue.h>
 #include <linux/seq_file.h>
 #include <linux/proc_fs.h>
+#include <linux/audit.h>
 
 #include <asm/unistd.h>
 
@@ -464,8 +467,10 @@ void ipc_rcu_putref(void *ptr)
  
 int ipcperms (struct kern_ipc_perm *ipcp, short flag)
 {	/* flag will most probably be 0 or S_...UGO from <linux/stat.h> */
-	int requested_mode, granted_mode;
+	int requested_mode, granted_mode, err;
 
+	if (unlikely((err = audit_ipc_obj(ipcp))))
+		return err;
 	requested_mode = (flag >> 6) | (flag >> 3) | flag;
 	granted_mode = ipcp->mode;
 	if (current->euid == ipcp->cuid || current->euid == ipcp->uid)