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Diffstat (limited to 'ipc/sem.c')
-rw-r--r--ipc/sem.c142
1 files changed, 101 insertions, 41 deletions
diff --git a/ipc/sem.c b/ipc/sem.c
index a4af04979fd2..06be75d9217a 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -88,13 +88,47 @@
#include <linux/uaccess.h>
#include "util.h"
+/* One semaphore structure for each semaphore in the system. */
+struct sem {
+ int semval; /* current value */
+ /*
+ * PID of the process that last modified the semaphore. For
+ * Linux, specifically these are:
+ * - semop
+ * - semctl, via SETVAL and SETALL.
+ * - at task exit when performing undo adjustments (see exit_sem).
+ */
+ struct pid *sempid;
+ spinlock_t lock; /* spinlock for fine-grained semtimedop */
+ struct list_head pending_alter; /* pending single-sop operations */
+ /* that alter the semaphore */
+ struct list_head pending_const; /* pending single-sop operations */
+ /* that do not alter the semaphore*/
+ time_t sem_otime; /* candidate for sem_otime */
+} ____cacheline_aligned_in_smp;
+
+/* One sem_array data structure for each set of semaphores in the system. */
+struct sem_array {
+ struct kern_ipc_perm sem_perm; /* permissions .. see ipc.h */
+ time64_t sem_ctime; /* create/last semctl() time */
+ struct list_head pending_alter; /* pending operations */
+ /* that alter the array */
+ struct list_head pending_const; /* pending complex operations */
+ /* that do not alter semvals */
+ struct list_head list_id; /* undo requests on this array */
+ int sem_nsems; /* no. of semaphores in array */
+ int complex_count; /* pending complex operations */
+ unsigned int use_global_lock;/* >0: global lock required */
+
+ struct sem sems[];
+} __randomize_layout;
/* One queue for each sleeping process in the system. */
struct sem_queue {
struct list_head list; /* queue of pending operations */
struct task_struct *sleeper; /* this process */
struct sem_undo *undo; /* undo structure */
- int pid; /* process id of requesting process */
+ struct pid *pid; /* process id of requesting process */
int status; /* completion status of operation */
struct sembuf *sops; /* array of pending operations */
struct sembuf *blocking; /* the operation that blocked */
@@ -265,7 +299,7 @@ static void sem_rcu_free(struct rcu_head *head)
struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu);
struct sem_array *sma = container_of(p, struct sem_array, sem_perm);
- security_sem_free(sma);
+ security_sem_free(&sma->sem_perm);
kvfree(sma);
}
@@ -495,7 +529,7 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params)
sma->sem_perm.key = key;
sma->sem_perm.security = NULL;
- retval = security_sem_alloc(sma);
+ retval = security_sem_alloc(&sma->sem_perm);
if (retval) {
kvfree(sma);
return retval;
@@ -533,17 +567,6 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params)
/*
* Called with sem_ids.rwsem and ipcp locked.
*/
-static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg)
-{
- struct sem_array *sma;
-
- sma = container_of(ipcp, struct sem_array, sem_perm);
- return security_sem_associate(sma, semflg);
-}
-
-/*
- * Called with sem_ids.rwsem and ipcp locked.
- */
static inline int sem_more_checks(struct kern_ipc_perm *ipcp,
struct ipc_params *params)
{
@@ -556,12 +579,12 @@ static inline int sem_more_checks(struct kern_ipc_perm *ipcp,
return 0;
}
-SYSCALL_DEFINE3(semget, key_t, key, int, nsems, int, semflg)
+long ksys_semget(key_t key, int nsems, int semflg)
{
struct ipc_namespace *ns;
static const struct ipc_ops sem_ops = {
.getnew = newary,
- .associate = sem_security,
+ .associate = security_sem_associate,
.more_checks = sem_more_checks,
};
struct ipc_params sem_params;
@@ -578,6 +601,11 @@ SYSCALL_DEFINE3(semget, key_t, key, int, nsems, int, semflg)
return ipcget(ns, &sem_ids(ns), &sem_ops, &sem_params);
}
+SYSCALL_DEFINE3(semget, key_t, key, int, nsems, int, semflg)
+{
+ return ksys_semget(key, nsems, semflg);
+}
+
/**
* perform_atomic_semop[_slow] - Attempt to perform semaphore
* operations on a given array.
@@ -597,7 +625,8 @@ SYSCALL_DEFINE3(semget, key_t, key, int, nsems, int, semflg)
*/
static int perform_atomic_semop_slow(struct sem_array *sma, struct sem_queue *q)
{
- int result, sem_op, nsops, pid;
+ int result, sem_op, nsops;
+ struct pid *pid;
struct sembuf *sop;
struct sem *curr;
struct sembuf *sops;
@@ -635,7 +664,7 @@ static int perform_atomic_semop_slow(struct sem_array *sma, struct sem_queue *q)
sop--;
pid = q->pid;
while (sop >= sops) {
- sma->sems[sop->sem_num].sempid = pid;
+ ipc_update_pid(&sma->sems[sop->sem_num].sempid, pid);
sop--;
}
@@ -722,7 +751,7 @@ static int perform_atomic_semop(struct sem_array *sma, struct sem_queue *q)
un->semadj[sop->sem_num] = undo;
}
curr->semval += sem_op;
- curr->sempid = q->pid;
+ ipc_update_pid(&curr->sempid, q->pid);
}
return 0;
@@ -1129,6 +1158,7 @@ static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
unlink_queue(sma, q);
wake_up_sem_queue_prepare(q, -EIDRM, &wake_q);
}
+ ipc_update_pid(&sem->sempid, NULL);
}
/* Remove the semaphore set from the IDR */
@@ -1190,14 +1220,14 @@ static int semctl_stat(struct ipc_namespace *ns, int semid,
memset(semid64, 0, sizeof(*semid64));
rcu_read_lock();
- if (cmd == SEM_STAT) {
+ if (cmd == SEM_STAT || cmd == SEM_STAT_ANY) {
sma = sem_obtain_object(ns, semid);
if (IS_ERR(sma)) {
err = PTR_ERR(sma);
goto out_unlock;
}
id = sma->sem_perm.id;
- } else {
+ } else { /* IPC_STAT */
sma = sem_obtain_object_check(ns, semid);
if (IS_ERR(sma)) {
err = PTR_ERR(sma);
@@ -1205,11 +1235,16 @@ static int semctl_stat(struct ipc_namespace *ns, int semid,
}
}
- err = -EACCES;
- if (ipcperms(ns, &sma->sem_perm, S_IRUGO))
- goto out_unlock;
+ /* see comment for SHM_STAT_ANY */
+ if (cmd == SEM_STAT_ANY)
+ audit_ipc_obj(&sma->sem_perm);
+ else {
+ err = -EACCES;
+ if (ipcperms(ns, &sma->sem_perm, S_IRUGO))
+ goto out_unlock;
+ }
- err = security_sem_semctl(sma, cmd);
+ err = security_sem_semctl(&sma->sem_perm, cmd);
if (err)
goto out_unlock;
@@ -1300,7 +1335,7 @@ static int semctl_setval(struct ipc_namespace *ns, int semid, int semnum,
return -EACCES;
}
- err = security_sem_semctl(sma, SETVAL);
+ err = security_sem_semctl(&sma->sem_perm, SETVAL);
if (err) {
rcu_read_unlock();
return -EACCES;
@@ -1321,7 +1356,7 @@ static int semctl_setval(struct ipc_namespace *ns, int semid, int semnum,
un->semadj[semnum] = 0;
curr->semval = val;
- curr->sempid = task_tgid_vnr(current);
+ ipc_update_pid(&curr->sempid, task_tgid(current));
sma->sem_ctime = ktime_get_real_seconds();
/* maybe some queued-up processes were waiting for this */
do_smart_update(sma, NULL, 0, 0, &wake_q);
@@ -1354,7 +1389,7 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
if (ipcperms(ns, &sma->sem_perm, cmd == SETALL ? S_IWUGO : S_IRUGO))
goto out_rcu_wakeup;
- err = security_sem_semctl(sma, cmd);
+ err = security_sem_semctl(&sma->sem_perm, cmd);
if (err)
goto out_rcu_wakeup;
@@ -1442,7 +1477,7 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
for (i = 0; i < nsems; i++) {
sma->sems[i].semval = sem_io[i];
- sma->sems[i].sempid = task_tgid_vnr(current);
+ ipc_update_pid(&sma->sems[i].sempid, task_tgid(current));
}
ipc_assert_locked_object(&sma->sem_perm);
@@ -1474,7 +1509,7 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
err = curr->semval;
goto out_unlock;
case GETPID:
- err = curr->sempid;
+ err = pid_vnr(curr->sempid);
goto out_unlock;
case GETNCNT:
err = count_semcnt(sma, semnum, 0);
@@ -1545,7 +1580,7 @@ static int semctl_down(struct ipc_namespace *ns, int semid,
sma = container_of(ipcp, struct sem_array, sem_perm);
- err = security_sem_semctl(sma, cmd);
+ err = security_sem_semctl(&sma->sem_perm, cmd);
if (err)
goto out_unlock1;
@@ -1576,7 +1611,7 @@ out_up:
return err;
}
-SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, unsigned long, arg)
+long ksys_semctl(int semid, int semnum, int cmd, unsigned long arg)
{
int version;
struct ipc_namespace *ns;
@@ -1596,6 +1631,7 @@ SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, unsigned long, arg)
return semctl_info(ns, semid, cmd, p);
case IPC_STAT:
case SEM_STAT:
+ case SEM_STAT_ANY:
err = semctl_stat(ns, semid, cmd, &semid64);
if (err < 0)
return err;
@@ -1630,6 +1666,11 @@ SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, unsigned long, arg)
}
}
+SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, unsigned long, arg)
+{
+ return ksys_semctl(semid, semnum, cmd, arg);
+}
+
#ifdef CONFIG_COMPAT
struct compat_semid_ds {
@@ -1678,7 +1719,7 @@ static int copy_compat_semid_to_user(void __user *buf, struct semid64_ds *in,
}
}
-COMPAT_SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, int, arg)
+long compat_ksys_semctl(int semid, int semnum, int cmd, int arg)
{
void __user *p = compat_ptr(arg);
struct ipc_namespace *ns;
@@ -1697,6 +1738,7 @@ COMPAT_SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, int, arg)
return semctl_info(ns, semid, cmd, p);
case IPC_STAT:
case SEM_STAT:
+ case SEM_STAT_ANY:
err = semctl_stat(ns, semid, cmd, &semid64);
if (err < 0)
return err;
@@ -1722,6 +1764,11 @@ COMPAT_SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, int, arg)
return -EINVAL;
}
}
+
+COMPAT_SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, int, arg)
+{
+ return compat_ksys_semctl(semid, semnum, cmd, arg);
+}
#endif
/* If the task doesn't already have a undo_list, then allocate one
@@ -1962,7 +2009,7 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops,
goto out_free;
}
- error = security_sem_semop(sma, sops, nsops, alter);
+ error = security_sem_semop(&sma->sem_perm, sops, nsops, alter);
if (error) {
rcu_read_unlock();
goto out_free;
@@ -1993,7 +2040,7 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops,
queue.sops = sops;
queue.nsops = nsops;
queue.undo = un;
- queue.pid = task_tgid_vnr(current);
+ queue.pid = task_tgid(current);
queue.alter = alter;
queue.dupsop = dupsop;
@@ -2120,8 +2167,8 @@ out_free:
return error;
}
-SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
- unsigned, nsops, const struct timespec __user *, timeout)
+long ksys_semtimedop(int semid, struct sembuf __user *tsops,
+ unsigned int nsops, const struct timespec __user *timeout)
{
if (timeout) {
struct timespec64 ts;
@@ -2132,10 +2179,16 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
return do_semtimedop(semid, tsops, nsops, NULL);
}
+SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
+ unsigned int, nsops, const struct timespec __user *, timeout)
+{
+ return ksys_semtimedop(semid, tsops, nsops, timeout);
+}
+
#ifdef CONFIG_COMPAT
-COMPAT_SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsems,
- unsigned, nsops,
- const struct compat_timespec __user *, timeout)
+long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems,
+ unsigned int nsops,
+ const struct compat_timespec __user *timeout)
{
if (timeout) {
struct timespec64 ts;
@@ -2145,6 +2198,13 @@ COMPAT_SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsems,
}
return do_semtimedop(semid, tsems, nsops, NULL);
}
+
+COMPAT_SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsems,
+ unsigned int, nsops,
+ const struct compat_timespec __user *, timeout)
+{
+ return compat_ksys_semtimedop(semid, tsems, nsops, timeout);
+}
#endif
SYSCALL_DEFINE3(semop, int, semid, struct sembuf __user *, tsops,
@@ -2287,7 +2347,7 @@ void exit_sem(struct task_struct *tsk)
semaphore->semval = 0;
if (semaphore->semval > SEMVMX)
semaphore->semval = SEMVMX;
- semaphore->sempid = task_tgid_vnr(current);
+ ipc_update_pid(&semaphore->sempid, task_tgid(current));
}
}
/* maybe some queued-up processes were waiting for this */
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-13 19:18:21 +0000