* /proc/sysvipc/sem support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
*
* SMP-threaded, sysctl's added
- * (c) 1999 Manfred Spraul <manfreds@colorfullife.com>
+ * (c) 1999 Manfred Spraul <manfred@colorfullife.com>
* Enforced range limit on SEM_UNDO
* (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>
#include <linux/time.h>
#include <linux/smp_lock.h>
#include <linux/security.h>
+#include <linux/syscalls.h>
+#include <linux/audit.h>
+#include <linux/capability.h>
+#include <linux/seq_file.h>
+#include <linux/mutex.h>
+
#include <asm/uaccess.h>
#include "util.h"
static int newary (key_t, int, int);
static void freeary (struct sem_array *sma, int id);
#ifdef CONFIG_PROC_FS
-static int sysvipc_sem_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data);
+static int sysvipc_sem_proc_show(struct seq_file *s, void *it);
#endif
#define SEMMSL_FAST 256 /* 512 bytes on stack */
{
used_sems = 0;
ipc_init_ids(&sem_ids,sc_semmni);
-
-#ifdef CONFIG_PROC_FS
- create_proc_read_entry("sysvipc/sem", 0, 0, sysvipc_sem_read_proc, NULL);
-#endif
+ ipc_init_proc_interface("sysvipc/sem",
+ " key semid perms nsems uid gid cuid cgid otime ctime\n",
+ &sem_ids,
+ sysvipc_sem_proc_show);
}
/*
* * if it's IN_WAKEUP, then it must wait until the value changes
* * if it's not -EINTR, then the operation was completed by
* update_queue. semtimedop can return queue.status without
- * performing any operation on the semaphore array.
+ * performing any operation on the sem array.
* * otherwise it must acquire the spinlock and check what's up.
*
* The two-stage algorithm is necessary to protect against the following
sma->sem_perm.mode = (semflg & S_IRWXUGO);
sma->sem_perm.key = key;
- sma->sem_perm.xid = current->xid;
+ sma->sem_perm.xid = vx_current_xid();
sma->sem_perm.security = NULL;
retval = security_sem_alloc(sma);
if (retval) {
- ipc_rcu_free(sma, size);
+ ipc_rcu_putref(sma);
return retval;
}
id = ipc_addid(&sem_ids, &sma->sem_perm, sc_semmni);
if(id == -1) {
security_sem_free(sma);
- ipc_rcu_free(sma, size);
+ ipc_rcu_putref(sma);
return -ENOSPC;
}
used_sems += nsems;
+ sma->sem_id = sem_buildid(id, sma->sem_perm.seq);
sma->sem_base = (struct sem *) &sma[1];
/* sma->sem_pending = NULL; */
sma->sem_pending_last = &sma->sem_pending;
sma->sem_ctime = get_seconds();
sem_unlock(sma);
- return sem_buildid(id, sma->sem_perm.seq);
+ return sma->sem_id;
}
asmlinkage long sys_semget (key_t key, int nsems, int semflg)
if (nsems < 0 || nsems > sc_semmsl)
return -EINVAL;
- down(&sem_ids.sem);
+ mutex_lock(&sem_ids.mutex);
if (key == IPC_PRIVATE) {
err = newary(key, nsems, semflg);
err = -EEXIST;
} else {
sma = sem_lock(id);
- if(sma==NULL)
- BUG();
+ BUG_ON(sma==NULL);
if (nsems > sma->sem_nsems)
err = -EINVAL;
else if (ipcperms(&sma->sem_perm, semflg))
sem_unlock(sma);
}
- up(&sem_ids.sem);
+ mutex_unlock(&sem_ids.mutex);
return err;
}
-/* doesn't acquire the sem_lock on error! */
-static int sem_revalidate(int semid, struct sem_array* sma, int nsems, short flg)
-{
- struct sem_array* smanew;
-
- smanew = sem_lock(semid);
- if(smanew==NULL)
- return -EIDRM;
- if(smanew != sma || sem_checkid(sma,semid) || sma->sem_nsems != nsems) {
- sem_unlock(smanew);
- return -EIDRM;
- }
-
- if (flg && ipcperms(&sma->sem_perm, flg)) {
- sem_unlock(smanew);
- return -EACCES;
- }
- return 0;
-}
/* Manage the doubly linked list sma->sem_pending as a FIFO:
* insert new queue elements at the tail sma->sem_pending_last.
*/
if (error <= 0) {
struct sem_queue *n;
remove_from_queue(sma,q);
- n = q->next;
q->status = IN_WAKEUP;
+ /*
+ * Continue scanning. The next operation
+ * that must be checked depends on the type of the
+ * completed operation:
+ * - if the operation modified the array, then
+ * restart from the head of the queue and
+ * check for threads that might be waiting
+ * for semaphore values to become 0.
+ * - if the operation didn't modify the array,
+ * then just continue.
+ */
+ if (q->alter)
+ n = sma->sem_pending;
+ else
+ n = q->next;
wake_up_process(q->sleeper);
/* hands-off: q will disappear immediately after
* writing q->status.
*/
+ smp_wmb();
q->status = error;
q = n;
} else {
return semzcnt;
}
-/* Free a semaphore set. freeary() is called with sem_ids.sem down and
- * the spinlock for this semaphore set hold. sem_ids.sem remains locked
+/* Free a semaphore set. freeary() is called with sem_ids.mutex locked and
+ * the spinlock for this semaphore set hold. sem_ids.mutex remains locked
* on exit.
*/
static void freeary (struct sem_array *sma, int id)
n = q->next;
q->status = IN_WAKEUP;
wake_up_process(q->sleeper); /* doesn't sleep */
+ smp_wmb();
q->status = -EIDRM; /* hands-off q */
q = n;
}
used_sems -= sma->sem_nsems;
size = sizeof (*sma) + sma->sem_nsems * sizeof (struct sem);
security_sem_free(sma);
- ipc_rcu_free(sma, size);
+ ipc_rcu_putref(sma);
}
static unsigned long copy_semid_to_user(void __user *buf, struct semid64_ds *in, int version)
seminfo.semmnu = SEMMNU;
seminfo.semmap = SEMMAP;
seminfo.semume = SEMUME;
- down(&sem_ids.sem);
+ mutex_lock(&sem_ids.mutex);
if (cmd == SEM_INFO) {
seminfo.semusz = sem_ids.in_use;
seminfo.semaem = used_sems;
seminfo.semaem = SEMAEM;
}
max_id = sem_ids.max_id;
- up(&sem_ids.sem);
+ mutex_unlock(&sem_ids.mutex);
if (copy_to_user (arg.__buf, &seminfo, sizeof(struct seminfo)))
return -EFAULT;
return (max_id < 0) ? 0: max_id;
struct semid64_ds tbuf;
int id;
- if(semid >= sem_ids.size)
+ if(semid >= sem_ids.entries->size)
return -EINVAL;
memset(&tbuf,0,sizeof(tbuf));
switch (cmd) {
case GETALL:
{
- ushort *array = arg.array;
+ ushort __user *array = arg.array;
int i;
if(nsems > SEMMSL_FAST) {
+ ipc_rcu_getref(sma);
sem_unlock(sma);
+
sem_io = ipc_alloc(sizeof(ushort)*nsems);
- if(sem_io == NULL)
+ if(sem_io == NULL) {
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ sem_unlock(sma);
return -ENOMEM;
- err = sem_revalidate(semid, sma, nsems, S_IRUGO);
- if(err)
+ }
+
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ if (sma->sem_perm.deleted) {
+ sem_unlock(sma);
+ err = -EIDRM;
goto out_free;
+ }
}
for (i = 0; i < sma->sem_nsems; i++)
int i;
struct sem_undo *un;
+ ipc_rcu_getref(sma);
sem_unlock(sma);
if(nsems > SEMMSL_FAST) {
sem_io = ipc_alloc(sizeof(ushort)*nsems);
- if(sem_io == NULL)
+ if(sem_io == NULL) {
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ sem_unlock(sma);
return -ENOMEM;
+ }
}
if (copy_from_user (sem_io, arg.array, nsems*sizeof(ushort))) {
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ sem_unlock(sma);
err = -EFAULT;
goto out_free;
}
for (i = 0; i < nsems; i++) {
if (sem_io[i] > SEMVMX) {
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ sem_unlock(sma);
err = -ERANGE;
goto out_free;
}
}
- err = sem_revalidate(semid, sma, nsems, S_IWUGO);
- if(err)
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ if (sma->sem_perm.deleted) {
+ sem_unlock(sma);
+ err = -EIDRM;
goto out_free;
+ }
for (i = 0; i < nsems; i++)
sma->sem_base[i].semval = sem_io[i];
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;
err = 0;
break;
case IPC_SET:
+ 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;
ipcp->mode = (ipcp->mode & ~S_IRWXUGO)
return err;
case IPC_RMID:
case IPC_SET:
- down(&sem_ids.sem);
+ mutex_lock(&sem_ids.mutex);
err = semctl_down(semid,semnum,cmd,version,arg);
- up(&sem_ids.sem);
+ mutex_unlock(&sem_ids.mutex);
return err;
default:
return -EINVAL;
struct sem_undo_list *undo_list;
undo_list = current->sysvsem.undo_list;
- if ((undo_list != NULL) && (atomic_read(&undo_list->refcnt) != 1))
+ if (undo_list)
spin_lock(&undo_list->lock);
}
struct sem_undo_list *undo_list;
undo_list = current->sysvsem.undo_list;
- if ((undo_list != NULL) && (atomic_read(&undo_list->refcnt) != 1))
+ if (undo_list)
spin_unlock(&undo_list->lock);
}
if (undo_list == NULL)
return -ENOMEM;
memset(undo_list, 0, size);
- /* don't initialize unodhd->lock here. It's done
- * in copy_semundo() instead.
- */
+ spin_lock_init(&undo_list->lock);
atomic_set(&undo_list->refcnt, 1);
current->sysvsem.undo_list = undo_list;
}
goto out;
}
nsems = sma->sem_nsems;
+ ipc_rcu_getref(sma);
sem_unlock(sma);
new = (struct sem_undo *) kmalloc(sizeof(struct sem_undo) + sizeof(short)*nsems, GFP_KERNEL);
- if (!new)
+ if (!new) {
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ sem_unlock(sma);
return ERR_PTR(-ENOMEM);
+ }
memset(new, 0, sizeof(struct sem_undo) + sizeof(short)*nsems);
new->semadj = (short *) &new[1];
new->semid = semid;
if (un) {
unlock_semundo();
kfree(new);
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ sem_unlock(sma);
goto out;
}
- error = sem_revalidate(semid, sma, nsems, 0);
- if (error) {
+ ipc_lock_by_ptr(&sma->sem_perm);
+ ipc_rcu_putref(sma);
+ if (sma->sem_perm.deleted) {
+ sem_unlock(sma);
unlock_semundo();
kfree(new);
- un = ERR_PTR(error);
+ un = ERR_PTR(-EIDRM);
goto out;
}
new->proc_next = ulp->proc_list;
struct sembuf fast_sops[SEMOPM_FAST];
struct sembuf* sops = fast_sops, *sop;
struct sem_undo *un;
- int undos = 0, decrease = 0, alter = 0, max;
+ int undos = 0, alter = 0, max;
struct sem_queue queue;
unsigned long jiffies_left = 0;
if (sop->sem_num >= max)
max = sop->sem_num;
if (sop->sem_flg & SEM_UNDO)
- undos++;
- if (sop->sem_op < 0)
- decrease = 1;
- if (sop->sem_op > 0)
+ undos = 1;
+ if (sop->sem_op != 0)
alter = 1;
}
- alter |= decrease;
retry_undos:
if (undos) {
goto out_unlock_free;
error = try_atomic_semop (sma, sops, nsops, un, current->tgid);
- if (error <= 0)
- goto update;
+ if (error <= 0) {
+ if (alter && error == 0)
+ update_queue (sma);
+ goto out_unlock_free;
+ }
/* We need to sleep on this operation, so we put the current
* task into the pending queue and go to sleep.
queue.undo = un;
queue.pid = current->tgid;
queue.id = semid;
+ queue.alter = alter;
if (alter)
append_to_queue(sma ,&queue);
else
sma = sem_lock(semid);
if(sma==NULL) {
- if(queue.prev != NULL)
- BUG();
+ BUG_ON(queue.prev != NULL);
error = -EIDRM;
goto out_free;
}
remove_from_queue(sma,&queue);
goto out_unlock_free;
-update:
- if (alter)
- update_queue (sma);
out_unlock_free:
sem_unlock(sma);
out_free:
error = get_undo_list(&undo_list);
if (error)
return error;
- if (atomic_read(&undo_list->refcnt) == 1)
- spin_lock_init(&undo_list->lock);
atomic_inc(&undo_list->refcnt);
tsk->sysvsem.undo_list = undo_list;
} else
/* perform adjustments registered in u */
nsems = sma->sem_nsems;
for (i = 0; i < nsems; i++) {
- struct sem * sem = &sma->sem_base[i];
+ struct sem * semaphore = &sma->sem_base[i];
if (u->semadj[i]) {
- sem->semval += u->semadj[i];
- if (sem->semval < 0)
- sem->semval = 0; /* shouldn't happen */
- sem->sempid = current->tgid;
+ semaphore->semval += u->semadj[i];
+ /*
+ * Range checks of the new semaphore value,
+ * not defined by sus:
+ * - Some unices ignore the undo entirely
+ * (e.g. HP UX 11i 11.22, Tru64 V5.1)
+ * - some cap the value (e.g. FreeBSD caps
+ * at 0, but doesn't enforce SEMVMX)
+ *
+ * Linux caps the semaphore value, both at 0
+ * and at SEMVMX.
+ *
+ * Manfred <manfred@colorfullife.com>
+ */
+ if (semaphore->semval < 0)
+ semaphore->semval = 0;
+ if (semaphore->semval > SEMVMX)
+ semaphore->semval = SEMVMX;
+ semaphore->sempid = current->tgid;
}
}
sma->sem_otime = get_seconds();
}
#ifdef CONFIG_PROC_FS
-static int sysvipc_sem_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data)
+static int sysvipc_sem_proc_show(struct seq_file *s, void *it)
{
- off_t pos = 0;
- off_t begin = 0;
- int i, len = 0;
+ struct sem_array *sma = it;
- len += sprintf(buffer, " key semid perms nsems uid gid cuid cgid otime ctime\n");
- down(&sem_ids.sem);
-
- for(i = 0; i <= sem_ids.max_id; i++) {
- struct sem_array *sma;
- sma = sem_lock(i);
- if (sma) {
- if (!vx_check(sma->sem_perm.xid, VX_IDENT)) {
- sem_unlock(sma);
- continue;
- }
- len += sprintf(buffer + len, "%10d %10d %4o %10lu %5u %5u %5u %5u %10lu %10lu\n",
- sma->sem_perm.key,
- sem_buildid(i,sma->sem_perm.seq),
- sma->sem_perm.mode,
- sma->sem_nsems,
- sma->sem_perm.uid,
- sma->sem_perm.gid,
- sma->sem_perm.cuid,
- sma->sem_perm.cgid,
- sma->sem_otime,
- sma->sem_ctime);
- sem_unlock(sma);
+ if (!vx_check(sma->sem_perm.xid, VX_IDENT))
+ return 0;
- pos += len;
- if(pos < offset) {
- len = 0;
- begin = pos;
- }
- if(pos > offset + length)
- goto done;
- }
- }
- *eof = 1;
-done:
- up(&sem_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 %5u %5u %5u %5u %10lu %10lu\n",
+ sma->sem_perm.key,
+ sma->sem_id,
+ sma->sem_perm.mode,
+ sma->sem_nsems,
+ sma->sem_perm.uid,
+ sma->sem_perm.gid,
+ sma->sem_perm.cuid,
+ sma->sem_perm.cgid,
+ sma->sem_otime,
+ sma->sem_ctime);
}
#endif
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