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semctl(): separate all layout-dependent copyin/copyout
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Signed-off-by: Al Viro <[email protected]>
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Al Viro committed Jul 16, 2017
1 parent 4693916 commit 45a4a64
Showing 1 changed file with 94 additions and 98 deletions.
192 changes: 94 additions & 98 deletions ipc/sem.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1177,112 +1177,95 @@ static time_t get_semotime(struct sem_array *sma)
return res;
}

static int semctl_nolock(struct ipc_namespace *ns, int semid,
int cmd, int version, void __user *p)
static int semctl_stat(struct ipc_namespace *ns, int semid,
int cmd, struct semid64_ds *semid64)
{
int err;
struct sem_array *sma;
int id = 0;
int err;

switch (cmd) {
case IPC_INFO:
case SEM_INFO:
{
struct seminfo seminfo;
int max_id;

err = security_sem_semctl(NULL, cmd);
if (err)
return err;
memset(semid64, 0, sizeof(*semid64));

memset(&seminfo, 0, sizeof(seminfo));
seminfo.semmni = ns->sc_semmni;
seminfo.semmns = ns->sc_semmns;
seminfo.semmsl = ns->sc_semmsl;
seminfo.semopm = ns->sc_semopm;
seminfo.semvmx = SEMVMX;
seminfo.semmnu = SEMMNU;
seminfo.semmap = SEMMAP;
seminfo.semume = SEMUME;
down_read(&sem_ids(ns).rwsem);
if (cmd == SEM_INFO) {
seminfo.semusz = sem_ids(ns).in_use;
seminfo.semaem = ns->used_sems;
} else {
seminfo.semusz = SEMUSZ;
seminfo.semaem = SEMAEM;
rcu_read_lock();
if (cmd == SEM_STAT) {
sma = sem_obtain_object(ns, semid);
if (IS_ERR(sma)) {
err = PTR_ERR(sma);
goto out_unlock;
}
id = sma->sem_perm.id;
} else {
sma = sem_obtain_object_check(ns, semid);
if (IS_ERR(sma)) {
err = PTR_ERR(sma);
goto out_unlock;
}
max_id = ipc_get_maxid(&sem_ids(ns));
up_read(&sem_ids(ns).rwsem);
if (copy_to_user(p, &seminfo, sizeof(struct seminfo)))
return -EFAULT;
return (max_id < 0) ? 0 : max_id;
}
case IPC_STAT:
case SEM_STAT:
{
struct semid64_ds tbuf;
int id = 0;

memset(&tbuf, 0, sizeof(tbuf));

rcu_read_lock();
if (cmd == SEM_STAT) {
sma = sem_obtain_object(ns, semid);
if (IS_ERR(sma)) {
err = PTR_ERR(sma);
goto out_unlock;
}
id = sma->sem_perm.id;
} else {
sma = sem_obtain_object_check(ns, semid);
if (IS_ERR(sma)) {
err = PTR_ERR(sma);
goto out_unlock;
}
}
err = -EACCES;
if (ipcperms(ns, &sma->sem_perm, S_IRUGO))
goto out_unlock;

err = -EACCES;
if (ipcperms(ns, &sma->sem_perm, S_IRUGO))
goto out_unlock;
err = security_sem_semctl(sma, cmd);
if (err)
goto out_unlock;

err = security_sem_semctl(sma, cmd);
if (err)
goto out_unlock;
kernel_to_ipc64_perm(&sma->sem_perm, &semid64->sem_perm);
semid64->sem_otime = get_semotime(sma);
semid64->sem_ctime = sma->sem_ctime;
semid64->sem_nsems = sma->sem_nsems;
rcu_read_unlock();
return id;

kernel_to_ipc64_perm(&sma->sem_perm, &tbuf.sem_perm);
tbuf.sem_otime = get_semotime(sma);
tbuf.sem_ctime = sma->sem_ctime;
tbuf.sem_nsems = sma->sem_nsems;
rcu_read_unlock();
if (copy_semid_to_user(p, &tbuf, version))
return -EFAULT;
return id;
}
default:
return -EINVAL;
}
out_unlock:
rcu_read_unlock();
return err;
}

static int semctl_info(struct ipc_namespace *ns, int semid,
int cmd, void __user *p)
{
struct seminfo seminfo;
int max_id;
int err;

err = security_sem_semctl(NULL, cmd);
if (err)
return err;

memset(&seminfo, 0, sizeof(seminfo));
seminfo.semmni = ns->sc_semmni;
seminfo.semmns = ns->sc_semmns;
seminfo.semmsl = ns->sc_semmsl;
seminfo.semopm = ns->sc_semopm;
seminfo.semvmx = SEMVMX;
seminfo.semmnu = SEMMNU;
seminfo.semmap = SEMMAP;
seminfo.semume = SEMUME;
down_read(&sem_ids(ns).rwsem);
if (cmd == SEM_INFO) {
seminfo.semusz = sem_ids(ns).in_use;
seminfo.semaem = ns->used_sems;
} else {
seminfo.semusz = SEMUSZ;
seminfo.semaem = SEMAEM;
}
max_id = ipc_get_maxid(&sem_ids(ns));
up_read(&sem_ids(ns).rwsem);
if (copy_to_user(p, &seminfo, sizeof(struct seminfo)))
return -EFAULT;
return (max_id < 0) ? 0 : max_id;
}

static int semctl_setval(struct ipc_namespace *ns, int semid, int semnum,
unsigned long arg)
int val)
{
struct sem_undo *un;
struct sem_array *sma;
struct sem *curr;
int err, val;
int err;
DEFINE_WAKE_Q(wake_q);

#if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN)
/* big-endian 64bit */
val = arg >> 32;
#else
/* 32bit or little-endian 64bit */
val = arg;
#endif

if (val > SEMVMX || val < 0)
return -ERANGE;

Expand Down Expand Up @@ -1531,23 +1514,17 @@ copy_semid_from_user(struct semid64_ds *out, void __user *buf, int version)
* NOTE: no locks must be held, the rwsem is taken inside this function.
*/
static int semctl_down(struct ipc_namespace *ns, int semid,
int cmd, int version, void __user *p)
int cmd, struct semid64_ds *semid64)
{
struct sem_array *sma;
int err;
struct semid64_ds semid64;
struct kern_ipc_perm *ipcp;

if (cmd == IPC_SET) {
if (copy_semid_from_user(&semid64, p, version))
return -EFAULT;
}

down_write(&sem_ids(ns).rwsem);
rcu_read_lock();

ipcp = ipcctl_pre_down_nolock(ns, &sem_ids(ns), semid, cmd,
&semid64.sem_perm, 0);
&semid64->sem_perm, 0);
if (IS_ERR(ipcp)) {
err = PTR_ERR(ipcp);
goto out_unlock1;
Expand All @@ -1567,7 +1544,7 @@ static int semctl_down(struct ipc_namespace *ns, int semid,
goto out_up;
case IPC_SET:
sem_lock(sma, NULL, -1);
err = ipc_update_perm(&semid64.sem_perm, ipcp);
err = ipc_update_perm(&semid64->sem_perm, ipcp);
if (err)
goto out_unlock0;
sma->sem_ctime = get_seconds();
Expand All @@ -1591,6 +1568,8 @@ SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, unsigned long, arg)
int version;
struct ipc_namespace *ns;
void __user *p = (void __user *)arg;
struct semid64_ds semid64;
int err;

if (semid < 0)
return -EINVAL;
Expand All @@ -1601,21 +1580,38 @@ SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, unsigned long, arg)
switch (cmd) {
case IPC_INFO:
case SEM_INFO:
return semctl_info(ns, semid, cmd, p);
case IPC_STAT:
case SEM_STAT:
return semctl_nolock(ns, semid, cmd, version, p);
err = semctl_stat(ns, semid, cmd, &semid64);
if (err < 0)
return err;
if (copy_semid_to_user(p, &semid64, version))
err = -EFAULT;
return err;
case GETALL:
case GETVAL:
case GETPID:
case GETNCNT:
case GETZCNT:
case SETALL:
return semctl_main(ns, semid, semnum, cmd, p);
case SETVAL:
return semctl_setval(ns, semid, semnum, arg);
case IPC_RMID:
case SETVAL: {
int val;
#if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN)
/* big-endian 64bit */
val = arg >> 32;
#else
/* 32bit or little-endian 64bit */
val = arg;
#endif
return semctl_setval(ns, semid, semnum, val);
}
case IPC_SET:
return semctl_down(ns, semid, cmd, version, p);
if (copy_semid_from_user(&semid64, p, version))
return -EFAULT;
case IPC_RMID:
return semctl_down(ns, semid, cmd, &semid64);
default:
return -EINVAL;
}
Expand Down

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