*
* mostly rewritten, threaded and wake-one semantics added
* MSGMAX limit removed, sysctl's added
- * (c) 1999 Manfred Spraul <manfreds@colorfullife.com>
+ * (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>
#include <linux/config.h>
#include <linux/slab.h>
#include <linux/msg.h>
#include <linux/list.h>
#include <linux/security.h>
#include <linux/sched.h>
-#include <linux/vs_base.h>
+#include <linux/syscalls.h>
+#include <linux/audit.h>
+#include <linux/seq_file.h>
+#include <linux/mutex.h>
#include <asm/current.h>
#include <asm/uaccess.h>
static void freeque (struct msg_queue *msq, int id);
static int newque (key_t key, int msgflg);
#ifdef CONFIG_PROC_FS
-static int sysvipc_msg_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data);
+static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
#endif
void __init msg_init (void)
{
ipc_init_ids(&msg_ids,msg_ctlmni);
-
-#ifdef CONFIG_PROC_FS
- create_proc_read_entry("sysvipc/msg", 0, 0, sysvipc_msg_read_proc, NULL);
-#endif
+ ipc_init_proc_interface("sysvipc/msg",
+ " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
+ &msg_ids,
+ sysvipc_msg_proc_show);
}
static int newque (key_t key, int msgflg)
msq->q_perm.mode = (msgflg & S_IRWXUGO);
msq->q_perm.key = key;
- msq->q_perm.xid = current->xid;
+ msq->q_perm.xid = vx_current_xid();
msq->q_perm.security = NULL;
retval = security_msg_queue_alloc(msq);
if (retval) {
- ipc_rcu_free(msq, sizeof(*msq));
+ ipc_rcu_putref(msq);
return retval;
}
id = ipc_addid(&msg_ids, &msq->q_perm, msg_ctlmni);
if(id == -1) {
security_msg_queue_free(msq);
- ipc_rcu_free(msq, sizeof(*msq));
+ ipc_rcu_putref(msq);
return -ENOSPC;
}
+ msq->q_id = msg_buildid(id,msq->q_perm.seq);
msq->q_stime = msq->q_rtime = 0;
msq->q_ctime = get_seconds();
msq->q_cbytes = msq->q_qnum = 0;
INIT_LIST_HEAD(&msq->q_senders);
msg_unlock(msq);
- return msg_buildid(id,msq->q_perm.seq);
+ return msq->q_id;
}
static inline void ss_add(struct msg_queue* msq, struct msg_sender* mss)
msr = list_entry(tmp,struct msg_receiver,r_list);
tmp = tmp->next;
- msr->r_msg = ERR_PTR(res);
+ msr->r_msg = NULL;
wake_up_process(msr->r_tsk);
+ smp_mb();
+ msr->r_msg = ERR_PTR(res);
}
}
/*
* removes the message queue from message queue ID
* array, and cleans up all the messages associated with this queue.
*
- * msg_ids.sem and the spinlock for this message queue is hold
- * before freeque() is called. msg_ids.sem remains locked on exit.
+ * msg_ids.mutex and the spinlock for this message queue is hold
+ * before freeque() is called. msg_ids.mutex remains locked on exit.
*/
static void freeque (struct msg_queue *msq, int id)
{
}
atomic_sub(msq->q_cbytes, &msg_bytes);
security_msg_queue_free(msq);
- ipc_rcu_free(msq, sizeof(struct msg_queue));
+ ipc_rcu_putref(msq);
}
asmlinkage long sys_msgget (key_t key, int msgflg)
int id, ret = -EPERM;
struct msg_queue *msq;
- down(&msg_ids.sem);
+ mutex_lock(&msg_ids.mutex);
if (key == IPC_PRIVATE)
ret = newque(key, msgflg);
else if ((id = ipc_findkey(&msg_ids, key)) == -1) { /* key not used */
ret = -EEXIST;
} else {
msq = msg_lock(id);
- if(msq==NULL)
- BUG();
+ BUG_ON(msq==NULL);
if (ipcperms(&msq->q_perm, msgflg))
ret = -EACCES;
else {
}
msg_unlock(msq);
}
- up(&msg_ids.sem);
+ mutex_unlock(&msg_ids.mutex);
return ret;
}
msginfo.msgmnb = msg_ctlmnb;
msginfo.msgssz = MSGSSZ;
msginfo.msgseg = MSGSEG;
- down(&msg_ids.sem);
+ mutex_lock(&msg_ids.mutex);
if (cmd == MSG_INFO) {
msginfo.msgpool = msg_ids.in_use;
msginfo.msgmap = atomic_read(&msg_hdrs);
msginfo.msgtql = MSGTQL;
}
max_id = msg_ids.max_id;
- up(&msg_ids.sem);
+ mutex_unlock(&msg_ids.mutex);
if (copy_to_user (buf, &msginfo, sizeof(struct msginfo)))
return -EFAULT;
return (max_id < 0) ? 0: max_id;
int success_return;
if (!buf)
return -EFAULT;
- if(cmd == MSG_STAT && msqid >= msg_ids.size)
+ if(cmd == MSG_STAT && msqid >= msg_ids.entries->size)
return -EINVAL;
memset(&tbuf,0,sizeof(tbuf));
return -EINVAL;
}
- down(&msg_ids.sem);
+ mutex_lock(&msg_ids.mutex);
msq = msg_lock(msqid);
err=-EINVAL;
if (msq == NULL)
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))
switch (cmd) {
case IPC_SET:
{
+ err = audit_ipc_set_perm(setbuf.qbytes, setbuf.uid, setbuf.gid, setbuf.mode, ipcp);
+ if (err)
+ goto out_unlock_up;
+
err = -EPERM;
if (setbuf.qbytes > msg_ctlmnb && !capable(CAP_SYS_RESOURCE))
goto out_unlock_up;
}
err = 0;
out_up:
- up(&msg_ids.sem);
+ mutex_unlock(&msg_ids.mutex);
return err;
out_unlock_up:
msg_unlock(msq);
!security_msg_queue_msgrcv(msq, msg, msr->r_tsk, msr->r_msgtype, msr->r_mode)) {
list_del(&msr->r_list);
if(msr->r_maxsize < msg->m_ts) {
- msr->r_msg = ERR_PTR(-E2BIG);
+ msr->r_msg = NULL;
wake_up_process(msr->r_tsk);
+ smp_mb();
+ msr->r_msg = ERR_PTR(-E2BIG);
} else {
- msr->r_msg = msg;
+ msr->r_msg = NULL;
msq->q_lrpid = msr->r_tsk->pid;
msq->q_rtime = get_seconds();
wake_up_process(msr->r_tsk);
+ smp_mb();
+ msr->r_msg = msg;
return 1;
}
}
err=-EINVAL;
if(msq==NULL)
goto out_free;
-retry:
+
err= -EIDRM;
if (msg_checkid(msq,msqid))
goto out_unlock_free;
- err=-EACCES;
- if (ipcperms(&msq->q_perm, S_IWUGO))
- goto out_unlock_free;
+ for (;;) {
+ struct msg_sender s;
- err = security_msg_queue_msgsnd(msq, msg, msgflg);
- if (err)
- goto out_unlock_free;
+ err=-EACCES;
+ if (ipcperms(&msq->q_perm, S_IWUGO))
+ goto out_unlock_free;
- if(msgsz + msq->q_cbytes > msq->q_qbytes ||
- 1 + msq->q_qnum > msq->q_qbytes) {
- struct msg_sender s;
+ err = security_msg_queue_msgsnd(msq, msg, msgflg);
+ if (err)
+ goto out_unlock_free;
+
+ if(msgsz + msq->q_cbytes <= msq->q_qbytes &&
+ 1 + msq->q_qnum <= msq->q_qbytes) {
+ break;
+ }
+ /* queue full, wait: */
if(msgflg&IPC_NOWAIT) {
err=-EAGAIN;
goto out_unlock_free;
}
ss_add(msq, &s);
+ ipc_rcu_getref(msq);
msg_unlock(msq);
schedule();
- current->state= TASK_RUNNING;
- msq = msg_lock(msqid);
- err = -EIDRM;
- if(msq==NULL)
- goto out_free;
+ ipc_lock_by_ptr(&msq->q_perm);
+ ipc_rcu_putref(msq);
+ if (msq->q_perm.deleted) {
+ err = -EIDRM;
+ goto out_unlock_free;
+ }
ss_del(&s);
if (signal_pending(current)) {
- err=-EINTR;
+ err=-ERESTARTNOHAND;
goto out_unlock_free;
}
- goto retry;
}
msq->q_lspid = current->tgid;
long msgtyp, int msgflg)
{
struct msg_queue *msq;
- struct msg_receiver msr_d;
- struct list_head* tmp;
- struct msg_msg* msg, *found_msg;
- int err;
+ struct msg_msg *msg;
int mode;
if (msqid < 0 || (long) msgsz < 0)
msq = msg_lock(msqid);
if(msq==NULL)
return -EINVAL;
-retry:
- err = -EIDRM;
+
+ msg = ERR_PTR(-EIDRM);
if (msg_checkid(msq,msqid))
goto out_unlock;
- err=-EACCES;
- if (ipcperms (&msq->q_perm, S_IRUGO))
- goto out_unlock;
+ for (;;) {
+ struct msg_receiver msr_d;
+ struct list_head* tmp;
- tmp = msq->q_messages.next;
- found_msg=NULL;
- while (tmp != &msq->q_messages) {
- msg = list_entry(tmp,struct msg_msg,m_list);
- if(testmsg(msg,msgtyp,mode) &&
- !security_msg_queue_msgrcv(msq, msg, current, msgtyp, mode)) {
- found_msg = msg;
- if(mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
- found_msg=msg;
- msgtyp=msg->m_type-1;
- } else {
- found_msg=msg;
- break;
- }
- }
- tmp = tmp->next;
- }
- if(found_msg) {
- msg=found_msg;
- if ((msgsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
- err=-E2BIG;
+ msg = ERR_PTR(-EACCES);
+ if (ipcperms (&msq->q_perm, S_IRUGO))
goto out_unlock;
+
+ msg = ERR_PTR(-EAGAIN);
+ tmp = msq->q_messages.next;
+ while (tmp != &msq->q_messages) {
+ struct msg_msg *walk_msg;
+ walk_msg = list_entry(tmp,struct msg_msg,m_list);
+ if(testmsg(walk_msg,msgtyp,mode) &&
+ !security_msg_queue_msgrcv(msq, walk_msg, current, msgtyp, mode)) {
+ msg = walk_msg;
+ if(mode == SEARCH_LESSEQUAL && walk_msg->m_type != 1) {
+ msg=walk_msg;
+ msgtyp=walk_msg->m_type-1;
+ } else {
+ msg=walk_msg;
+ break;
+ }
+ }
+ tmp = tmp->next;
}
- list_del(&msg->m_list);
- msq->q_qnum--;
- msq->q_rtime = get_seconds();
- msq->q_lrpid = current->tgid;
- msq->q_cbytes -= msg->m_ts;
- atomic_sub(msg->m_ts,&msg_bytes);
- atomic_dec(&msg_hdrs);
- ss_wakeup(&msq->q_senders,0);
- msg_unlock(msq);
-out_success:
- msgsz = (msgsz > msg->m_ts) ? msg->m_ts : msgsz;
- if (put_user (msg->m_type, &msgp->mtype) ||
- store_msg(msgp->mtext, msg, msgsz)) {
- msgsz = -EFAULT;
+ if(!IS_ERR(msg)) {
+ /* Found a suitable message. Unlink it from the queue. */
+ if ((msgsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
+ msg = ERR_PTR(-E2BIG);
+ goto out_unlock;
+ }
+ list_del(&msg->m_list);
+ msq->q_qnum--;
+ msq->q_rtime = get_seconds();
+ msq->q_lrpid = current->tgid;
+ msq->q_cbytes -= msg->m_ts;
+ atomic_sub(msg->m_ts,&msg_bytes);
+ atomic_dec(&msg_hdrs);
+ ss_wakeup(&msq->q_senders,0);
+ msg_unlock(msq);
+ break;
}
- free_msg(msg);
- return msgsz;
- } else
- {
- /* no message waiting. Prepare for pipelined
- * receive.
- */
+ /* No message waiting. Wait for a message */
if (msgflg & IPC_NOWAIT) {
- err=-ENOMSG;
+ msg = ERR_PTR(-ENOMSG);
goto out_unlock;
}
list_add_tail(&msr_d.r_list,&msq->q_receivers);
if(msgflg & MSG_NOERROR)
msr_d.r_maxsize = INT_MAX;
else
- msr_d.r_maxsize = msgsz;
+ msr_d.r_maxsize = msgsz;
msr_d.r_msg = ERR_PTR(-EAGAIN);
current->state = TASK_INTERRUPTIBLE;
msg_unlock(msq);
schedule();
- /*
- * The below optimisation is buggy. A sleeping thread that is
- * woken up checks if it got a message and if so, copies it to
- * userspace and just returns without taking any locks.
- * But this return to user space can be faster than the message
- * send, and if the receiver immediately exits the
- * wake_up_process performed by the sender will oops.
+ /* Lockless receive, part 1:
+ * Disable preemption. We don't hold a reference to the queue
+ * and getting a reference would defeat the idea of a lockless
+ * operation, thus the code relies on rcu to guarantee the
+ * existance of msq:
+ * Prior to destruction, expunge_all(-EIRDM) changes r_msg.
+ * Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
+ * rcu_read_lock() prevents preemption between reading r_msg
+ * and the spin_lock() inside ipc_lock_by_ptr().
+ */
+ rcu_read_lock();
+
+ /* Lockless receive, part 2:
+ * Wait until pipelined_send or expunge_all are outside of
+ * wake_up_process(). There is a race with exit(), see
+ * ipc/mqueue.c for the details.
*/
-#if 0
msg = (struct msg_msg*) msr_d.r_msg;
- if(!IS_ERR(msg))
- goto out_success;
-#endif
+ while (msg == NULL) {
+ cpu_relax();
+ msg = (struct msg_msg*) msr_d.r_msg;
+ }
- msq = msg_lock(msqid);
- msg = (struct msg_msg*)msr_d.r_msg;
- if(!IS_ERR(msg)) {
- /* our message arived while we waited for
- * the spinlock. Process it.
- */
- if(msq)
- msg_unlock(msq);
- goto out_success;
+ /* Lockless receive, part 3:
+ * If there is a message or an error then accept it without
+ * locking.
+ */
+ if(msg != ERR_PTR(-EAGAIN)) {
+ rcu_read_unlock();
+ break;
}
- err = PTR_ERR(msg);
- if(err == -EAGAIN) {
- if(!msq)
- BUG();
- list_del(&msr_d.r_list);
- if (signal_pending(current))
- err=-EINTR;
- else
- goto retry;
+
+ /* Lockless receive, part 3:
+ * Acquire the queue spinlock.
+ */
+ ipc_lock_by_ptr(&msq->q_perm);
+ rcu_read_unlock();
+
+ /* Lockless receive, part 4:
+ * Repeat test after acquiring the spinlock.
+ */
+ msg = (struct msg_msg*)msr_d.r_msg;
+ if(msg != ERR_PTR(-EAGAIN))
+ goto out_unlock;
+
+ list_del(&msr_d.r_list);
+ if (signal_pending(current)) {
+ msg = ERR_PTR(-ERESTARTNOHAND);
+out_unlock:
+ msg_unlock(msq);
+ break;
}
}
-out_unlock:
- if(msq)
- msg_unlock(msq);
- return err;
+ if (IS_ERR(msg))
+ return PTR_ERR(msg);
+
+ msgsz = (msgsz > msg->m_ts) ? msg->m_ts : msgsz;
+ if (put_user (msg->m_type, &msgp->mtype) ||
+ store_msg(msgp->mtext, msg, msgsz)) {
+ msgsz = -EFAULT;
+ }
+ free_msg(msg);
+ return msgsz;
}
#ifdef CONFIG_PROC_FS
-static int sysvipc_msg_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data)
+static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
{
- off_t pos = 0;
- off_t begin = 0;
- int i, len = 0;
-
- down(&msg_ids.sem);
- len += sprintf(buffer, " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n");
-
- for(i = 0; i <= msg_ids.max_id; i++) {
- struct msg_queue * msq;
- msq = msg_lock(i);
- if (msq) {
- if (!vx_check(msq->q_perm.xid, VX_IDENT)) {
- msg_unlock(msq);
- continue;
- }
- len += sprintf(buffer + len, "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n",
- msq->q_perm.key,
- msg_buildid(i,msq->q_perm.seq),
- msq->q_perm.mode,
- msq->q_cbytes,
- msq->q_qnum,
- msq->q_lspid,
- msq->q_lrpid,
- msq->q_perm.uid,
- msq->q_perm.gid,
- msq->q_perm.cuid,
- msq->q_perm.cgid,
- msq->q_stime,
- msq->q_rtime,
- msq->q_ctime);
- msg_unlock(msq);
+ struct msg_queue *msq = it;
- pos += len;
- if(pos < offset) {
- len = 0;
- begin = pos;
- }
- if(pos > offset + length)
- goto done;
- }
+ if (!vx_check(msq->q_perm.xid, VX_IDENT))
+ return 0;
- }
- *eof = 1;
-done:
- up(&msg_ids.sem);
- *start = buffer + (offset - begin);
- len -= (offset - begin);
- if(len > length)
- len = length;
- if(len < 0)
- len = 0;
- return len;
+ return seq_printf(s,
+ "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n",
+ msq->q_perm.key,
+ msq->q_id,
+ msq->q_perm.mode,
+ msq->q_cbytes,
+ msq->q_qnum,
+ msq->q_lspid,
+ msq->q_lrpid,
+ msq->q_perm.uid,
+ msq->q_perm.gid,
+ msq->q_perm.cuid,
+ msq->q_perm.cgid,
+ msq->q_stime,
+ msq->q_rtime,
+ msq->q_ctime);
}
#endif
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