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authorDavidlohr Bueso <davidlohr.bueso@hp.com>2013-09-11 14:26:21 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-11 15:59:41 -0700
commit2caacaa82a51b78fc0c800e206473874094287ed (patch)
tree07dfe1f340d35d907de80f4a80296c72896cef2c /ipc
parentc97cb9ccab8c85428ec21eff690642ad2ce1fa8a (diff)
downloadlinux-2caacaa82a51b78fc0c800e206473874094287ed.tar.gz
ipc,shm: shorten critical region for shmctl
With the *_INFO, *_STAT, IPC_RMID and IPC_SET commands already optimized, deal with the remaining SHM_LOCK and SHM_UNLOCK commands. Take the shm_perm lock after doing the initial auditing and security checks. The rest of the logic remains unchanged. Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'ipc')
-rw-r--r--ipc/shm.c49
1 files changed, 25 insertions, 24 deletions
diff --git a/ipc/shm.c b/ipc/shm.c
index a493639550d..8ec381085de 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -940,10 +940,8 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
int err, version;
struct ipc_namespace *ns;
- if (cmd < 0 || shmid < 0) {
- err = -EINVAL;
- goto out;
- }
+ if (cmd < 0 || shmid < 0)
+ return -EINVAL;
version = ipc_parse_version(&cmd);
ns = current->nsproxy->ipc_ns;
@@ -954,36 +952,40 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
case SHM_STAT:
case IPC_STAT:
return shmctl_nolock(ns, shmid, cmd, version, buf);
+ case IPC_RMID:
+ case IPC_SET:
+ return shmctl_down(ns, shmid, cmd, buf, version);
case SHM_LOCK:
case SHM_UNLOCK:
{
struct file *shm_file;
- shp = shm_lock_check(ns, shmid);
+ rcu_read_lock();
+ shp = shm_obtain_object_check(ns, shmid);
if (IS_ERR(shp)) {
err = PTR_ERR(shp);
- goto out;
+ goto out_unlock1;
}
audit_ipc_obj(&(shp->shm_perm));
+ err = security_shm_shmctl(shp, cmd);
+ if (err)
+ goto out_unlock1;
+ ipc_lock_object(&shp->shm_perm);
if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
kuid_t euid = current_euid();
err = -EPERM;
if (!uid_eq(euid, shp->shm_perm.uid) &&
!uid_eq(euid, shp->shm_perm.cuid))
- goto out_unlock;
+ goto out_unlock0;
if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
- goto out_unlock;
+ goto out_unlock0;
}
- err = security_shm_shmctl(shp, cmd);
- if (err)
- goto out_unlock;
-
shm_file = shp->shm_file;
if (is_file_hugepages(shm_file))
- goto out_unlock;
+ goto out_unlock0;
if (cmd == SHM_LOCK) {
struct user_struct *user = current_user();
@@ -992,32 +994,31 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
shp->shm_perm.mode |= SHM_LOCKED;
shp->mlock_user = user;
}
- goto out_unlock;
+ goto out_unlock0;
}
/* SHM_UNLOCK */
if (!(shp->shm_perm.mode & SHM_LOCKED))
- goto out_unlock;
+ goto out_unlock0;
shmem_lock(shm_file, 0, shp->mlock_user);
shp->shm_perm.mode &= ~SHM_LOCKED;
shp->mlock_user = NULL;
get_file(shm_file);
- shm_unlock(shp);
+ ipc_unlock_object(&shp->shm_perm);
+ rcu_read_unlock();
shmem_unlock_mapping(shm_file->f_mapping);
+
fput(shm_file);
- goto out;
- }
- case IPC_RMID:
- case IPC_SET:
- err = shmctl_down(ns, shmid, cmd, buf, version);
return err;
+ }
default:
return -EINVAL;
}
-out_unlock:
- shm_unlock(shp);
-out:
+out_unlock0:
+ ipc_unlock_object(&shp->shm_perm);
+out_unlock1:
+ rcu_read_unlock();
return err;
}