X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fnsproxy.c;h=adc785146a1cb81d6f7b3d676877921f10bb59e7;hb=9aef85cc58f54f01bbbafdb3c87af4465f4257c0;hp=f5d332cf8c631704b1ee440c35317644e4f6eff9;hpb=03054de1e0b90b33e9974107d84dabd2509f5898;p=linux-2.6

diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index f5d332cf8c..adc785146a 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -139,6 +139,18 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
 		goto out;
 	}
 
+	/*
+	 * CLONE_NEWIPC must detach from the undolist: after switching
+	 * to a new ipc namespace, the semaphore arrays from the old
+	 * namespace are unreachable.  In clone parlance, CLONE_SYSVSEM
+	 * means share undolist with parent, so we must forbid using
+	 * it along with CLONE_NEWIPC.
+	 */
+	if ((flags & CLONE_NEWIPC) && (flags & CLONE_SYSVSEM)) {
+		err = -EINVAL;
+		goto out;
+	}
+
 	new_ns = create_new_namespaces(flags, tsk, tsk->fs);
 	if (IS_ERR(new_ns)) {
 		err = PTR_ERR(new_ns);