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[PATCH] Rework of IPC auditing

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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>
This commit is contained in:
Steve Grubb 2006-04-02 17:07:33 -04:00 committed by Al Viro
parent ce29b682e2
commit 073115d6b2
6 changed files with 98 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
include/linux/audit.h
View file

@ -83,6 +83,7 @@
#define AUDIT_CONFIG_CHANGE 1305 /* Audit system configuration change */
#define AUDIT_SOCKADDR 1306 /* sockaddr copied as syscall arg */
#define AUDIT_CWD 1307 /* Current working directory */
#define AUDIT_IPC_SET_PERM 1311 /* IPC new permissions record type */
#define AUDIT_AVC 1400 /* SE Linux avc denial or grant */
#define AUDIT_SELINUX_ERR 1401 /* Internal SE Linux Errors */
@ -319,7 +320,8 @@ extern void auditsc_get_stamp(struct audit_context *ctx,
struct timespec *t, unsigned int *serial);
extern int audit_set_loginuid(struct task_struct *task, uid_t loginuid);
extern uid_t audit_get_loginuid(struct audit_context *ctx);
extern int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode, struct kern_ipc_perm *ipcp);
extern int audit_ipc_obj(struct kern_ipc_perm *ipcp);
extern int audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode, struct kern_ipc_perm *ipcp);
extern int audit_socketcall(int nargs, unsigned long *args);
extern int audit_sockaddr(int len, void *addr);
extern int audit_avc_path(struct dentry *dentry, struct vfsmount *mnt);
@ -338,7 +340,8 @@ extern int audit_set_macxattr(const char *name);
#define audit_inode_child(d,i,p) do { ; } while (0)
#define auditsc_get_stamp(c,t,s) do { BUG(); } while (0)
#define audit_get_loginuid(c) ({ -1; })
#define audit_ipc_perms(q,u,g,m,i) ({ 0; })
#define audit_ipc_obj(i) ({ 0; })
#define audit_ipc_set_perm(q,u,g,m,i) ({ 0; })
#define audit_socketcall(n,a) ({ 0; })
#define audit_sockaddr(len, addr) ({ 0; })
#define audit_avc_path(dentry, mnt) ({ 0; })

11
ipc/msg.c
View file

@ -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;

11
ipc/sem.c
View file

@ -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;

19
ipc/shm.c
View file

@ -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 &&

7
ipc/util.c
View file

@ -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)

54
kernel/auditsc.c
View file

@ -646,6 +646,25 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
}
break; }
case AUDIT_IPC_SET_PERM: {
struct audit_aux_data_ipcctl *axi = (void *)aux;
audit_log_format(ab,
" new qbytes=%lx new iuid=%u new igid=%u new mode=%x",
axi->qbytes, axi->uid, axi->gid, axi->mode);
if (axi->osid != 0) {
char *ctx = NULL;
u32 len;
if (selinux_ctxid_to_string(
axi->osid, &ctx, &len)) {
audit_log_format(ab, " osid=%u",
axi->osid);
call_panic = 1;
} else
audit_log_format(ab, " obj=%s", ctx);
kfree(ctx);
}
break; }
case AUDIT_SOCKETCALL: {
int i;
struct audit_aux_data_socketcall *axs = (void *)aux;
@ -1148,7 +1167,36 @@ uid_t audit_get_loginuid(struct audit_context *ctx)
}
/**
* audit_ipc_perms - record audit data for ipc
* audit_ipc_obj - record audit data for ipc object
* @ipcp: ipc permissions
*
* Returns 0 for success or NULL context or < 0 on error.
*/
int audit_ipc_obj(struct kern_ipc_perm *ipcp)
{
struct audit_aux_data_ipcctl *ax;
struct audit_context *context = current->audit_context;
if (likely(!context))
return 0;
ax = kmalloc(sizeof(*ax), GFP_ATOMIC);
if (!ax)
return -ENOMEM;
ax->uid = ipcp->uid;
ax->gid = ipcp->gid;
ax->mode = ipcp->mode;
selinux_get_ipc_sid(ipcp, &ax->osid);
ax->d.type = AUDIT_IPC;
ax->d.next = context->aux;
context->aux = (void *)ax;
return 0;
}
/**
* audit_ipc_set_perm - record audit data for new ipc permissions
* @qbytes: msgq bytes
* @uid: msgq user id
* @gid: msgq group id
@ -1156,7 +1204,7 @@ uid_t audit_get_loginuid(struct audit_context *ctx)
*
* Returns 0 for success or NULL context or < 0 on error.
*/
int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode, struct kern_ipc_perm *ipcp)
int audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode, struct kern_ipc_perm *ipcp)
{
struct audit_aux_data_ipcctl *ax;
struct audit_context *context = current->audit_context;
@ -1174,7 +1222,7 @@ int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode, str
ax->mode = mode;
selinux_get_ipc_sid(ipcp, &ax->osid);
ax->d.type = AUDIT_IPC;
ax->d.type = AUDIT_IPC_SET_PERM;
ax->d.next = context->aux;
context->aux = (void *)ax;
return 0;