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-rw-r--r--ipc/util.c31
1 files changed, 26 insertions, 5 deletions
diff --git a/ipc/util.c b/ipc/util.c
index 813804ebdeba..3df0af3158a5 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -824,11 +824,28 @@ struct kern_ipc_perm *ipcctl_pre_down(struct ipc_namespace *ns,
struct ipc64_perm *perm, int extra_perm)
{
struct kern_ipc_perm *ipcp;
+
+ ipcp = ipcctl_pre_down_nolock(ns, ids, id, cmd, perm, extra_perm);
+ if (IS_ERR(ipcp))
+ goto out;
+
+ spin_lock(&ipcp->lock);
+out:
+ return ipcp;
+}
+
+struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns,
+ struct ipc_ids *ids, int id, int cmd,
+ struct ipc64_perm *perm, int extra_perm)
+{
kuid_t euid;
- int err;
+ int err = -EPERM;
+ struct kern_ipc_perm *ipcp;
down_write(&ids->rw_mutex);
- ipcp = ipc_lock_check(ids, id);
+ rcu_read_lock();
+
+ ipcp = ipc_obtain_object_check(ids, id);
if (IS_ERR(ipcp)) {
err = PTR_ERR(ipcp);
goto out_up;
@@ -837,17 +854,21 @@ struct kern_ipc_perm *ipcctl_pre_down(struct ipc_namespace *ns,
audit_ipc_obj(ipcp);
if (cmd == IPC_SET)
audit_ipc_set_perm(extra_perm, perm->uid,
- perm->gid, perm->mode);
+ perm->gid, perm->mode);
euid = current_euid();
if (uid_eq(euid, ipcp->cuid) || uid_eq(euid, ipcp->uid) ||
ns_capable(ns->user_ns, CAP_SYS_ADMIN))
return ipcp;
- err = -EPERM;
- ipc_unlock(ipcp);
out_up:
+ /*
+ * Unsuccessful lookup, unlock and return
+ * the corresponding error.
+ */
+ rcu_read_unlock();
up_write(&ids->rw_mutex);
+
return ERR_PTR(err);
}

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