GitHub-Mirror/Star64_linux
2
0
Fork 0
mirror of https://github.com/Fishwaldo/Star64_linux.git synced 2025-07-01 11:21:51 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

userns: Don't allow setgroups until a gid mapping has been setablished

Browse source 
setgroups is unique in not needing a valid mapping before it can be called,
in the case of setgroups(0, NULL) which drops all supplemental groups.

The design of the user namespace assumes that CAP_SETGID can not actually
be used until a gid mapping is established.  Therefore add a helper function
to see if the user namespace gid mapping has been established and call
that function in the setgroups permission check.

This is part of the fix for CVE-2014-8989, being able to drop groups
without privilege using user namespaces.

Cc: stable@vger.kernel.org
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
This commit is contained in:
Eric W. Biederman 2014-12-05 18:01:11 -06:00
parent 0542f17bf2
commit 273d2c67c3
3 changed files with 22 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

5
include/linux/user_namespace.h
View file

@ -63,6 +63,7 @@ extern const struct seq_operations proc_projid_seq_operations;
extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
extern bool userns_may_setgroups(const struct user_namespace *ns);
#else
static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
@ -87,6 +88,10 @@ static inline void put_user_ns(struct user_namespace *ns)
{
}
static inline bool userns_may_setgroups(const struct user_namespace *ns)
{
return true;
}
#endif
#endif /* _LINUX_USER_H */