From d07b846f6200454c50d791796edb82660192513d Mon Sep 17 00:00:00 2001 From: Seth Forshee Date: Wed, 23 Sep 2015 15:16:04 -0500 Subject: fs: Limit file caps to the user namespace of the super block Capability sets attached to files must be ignored except in the user namespaces where the mounter is privileged, i.e. s_user_ns and its descendants. Otherwise a vector exists for gaining privileges in namespaces where a user is not already privileged. Add a new helper function, current_in_user_ns(), to test whether a user namespace is the same as or a descendant of another namespace. Use this helper to determine whether a file's capability set should be applied to the caps constructed during exec. --EWB Replaced in_userns with the simpler current_in_userns. Acked-by: Serge Hallyn Signed-off-by: Seth Forshee Signed-off-by: Eric W. Biederman --- include/linux/user_namespace.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/linux/user_namespace.h') diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index 8297e5b341d8..9217169c64cb 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -72,6 +72,7 @@ extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *); extern int proc_setgroups_show(struct seq_file *m, void *v); extern bool userns_may_setgroups(const struct user_namespace *ns); +extern bool current_in_userns(const struct user_namespace *target_ns); #else static inline struct user_namespace *get_user_ns(struct user_namespace *ns) @@ -100,6 +101,11 @@ static inline bool userns_may_setgroups(const struct user_namespace *ns) { return true; } + +static inline bool current_in_userns(const struct user_namespace *target_ns) +{ + return true; +} #endif #endif /* _LINUX_USER_H */ -- cgit