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-rw-r--r--security/commoncap.c25
1 files changed, 17 insertions, 8 deletions
diff --git a/security/commoncap.c b/security/commoncap.c
index 6dbae4650abe..7ee08c756d6b 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -76,24 +76,33 @@ int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
int cap_capable(const struct cred *cred, struct user_namespace *targ_ns,
int cap, int audit)
{
- for (;;) {
- /* The owner of the user namespace has all caps. */
- if (targ_ns != &init_user_ns && uid_eq(targ_ns->owner, cred->euid))
- return 0;
+ struct user_namespace *ns = targ_ns;
+ /* See if cred has the capability in the target user namespace
+ * by examining the target user namespace and all of the target
+ * user namespace's parents.
+ */
+ for (;;) {
/* Do we have the necessary capabilities? */
- if (targ_ns == cred->user_ns)
+ if (ns == cred->user_ns)
return cap_raised(cred->cap_effective, cap) ? 0 : -EPERM;
/* Have we tried all of the parent namespaces? */
- if (targ_ns == &init_user_ns)
+ if (ns == &init_user_ns)
return -EPERM;
+ /*
+ * The owner of the user namespace in the parent of the
+ * user namespace has all caps.
+ */
+ if ((ns->parent == cred->user_ns) && uid_eq(ns->owner, cred->euid))
+ return 0;
+
/*
- *If you have a capability in a parent user ns, then you have
+ * If you have a capability in a parent user ns, then you have
* it over all children user namespaces as well.
*/
- targ_ns = targ_ns->parent;
+ ns = ns->parent;
}
/* We never get here */