aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/cred.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/cred.c')
-rw-r--r--kernel/cred.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/kernel/cred.c b/kernel/cred.c
index ecf03657e71c..efd04b2ec84c 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -448,6 +448,15 @@ int commit_creds(struct cred *new)
if (task->mm)
set_dumpable(task->mm, suid_dumpable);
task->pdeath_signal = 0;
+ /*
+ * If a task drops privileges and becomes nondumpable,
+ * the dumpability change must become visible before
+ * the credential change; otherwise, a __ptrace_may_access()
+ * racing with this change may be able to attach to a task it
+ * shouldn't be able to attach to (as if the task had dropped
+ * privileges without becoming nondumpable).
+ * Pairs with a read barrier in __ptrace_may_access().
+ */
smp_wmb();
}