From: Krzysztof Struczynski <krzysztof.struczynski@xxxxxxxxxx>
Add function that checks if the UID map is defined. It will be used by
ima to check if ID remapping in subject-based rules is necessary.
Signed-off-by: Krzysztof Struczynski <krzysztof.struczynski@xxxxxxxxxx>
---
include/linux/user_namespace.h | 6 ++++++
kernel/user_namespace.c | 11 +++++++++++
2 files changed, 17 insertions(+)
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index d9759c54fead..bcb21c41c910 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -138,6 +138,7 @@ extern bool in_userns(const struct user_namespace *ancestor,
const struct user_namespace *child);
extern bool current_in_userns(const struct user_namespace *target_ns);
struct ns_common *ns_get_owner(struct ns_common *ns);
+extern bool userns_set_uidmap(const struct user_namespace *ns);
#else
static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
@@ -182,6 +183,11 @@ static inline struct ns_common *ns_get_owner(struct ns_common *ns)
{
return ERR_PTR(-EPERM);
}
+
+static inline bool userns_set_uidmap(const struct user_namespace *ns)
+{
+ return true;
+}
#endif
#endif /* _LINUX_USER_H */
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 87804e0371fe..e38f9f11a589 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -1232,6 +1232,17 @@ bool current_in_userns(const struct user_namespace *target_ns)
}
EXPORT_SYMBOL(current_in_userns);
+bool userns_set_uidmap(const struct user_namespace *ns)
+{
+ bool mapping_defined;
+
+ mutex_lock(&userns_state_mutex);
+ mapping_defined = ns->uid_map.nr_extents != 0;
+ mutex_unlock(&userns_state_mutex);
+
+ return mapping_defined;
+}
+
static inline struct user_namespace *to_user_ns(struct ns_common *ns)
{
return container_of(ns, struct user_namespace, ns);
--
2.20.1
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