mirror of
https://github.com/LineageOS/android_kernel_samsung_msm8226.git
synced 2026-09-29 00:00:25 +02:00
Eric W. Biederman
80f4b770f4
Assign a unique proc inode to each namespace, and use that inode number to ensure we only allocate at most one proc inode for every namespace in proc. A single proc inode per namespace allows userspace to test to see if two processes are in the same namespace. This has been a long requested feature and only blocked because a naive implementation would put the id in a global space and would ultimately require having a namespace for the names of namespaces, making migration and certain virtualization tricks impossible. We still don't have per superblock inode numbers for proc, which appears necessary for application unaware checkpoint/restart and migrations (if the application is using namespace file descriptors) but that is now allowd by the design if it becomes important. I have preallocated the ipc and uts initial proc inode numbers so their structures can be statically initialized. Change-Id: I01d42c2f051fd74b1474d9d8378ccc78174cf3cf Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Git-commit: f80cd4676998eb352d1a8b9df0f3663537a9ce93 Git-repo: https://android.googlesource.com/kernel/common/ [schikk@codeaurora.org: Resolved merge conflicts ] CRs-Fixed: 901628 Signed-off-by: Swetha Chikkaboraiah <schikk@codeaurora.org>
73 lines
1.5 KiB
C
73 lines
1.5 KiB
C
#ifndef _LINUX_USER_NAMESPACE_H
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#define _LINUX_USER_NAMESPACE_H
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#include <linux/kref.h>
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#include <linux/nsproxy.h>
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#include <linux/sched.h>
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#include <linux/err.h>
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#define UIDHASH_BITS (CONFIG_BASE_SMALL ? 3 : 7)
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#define UIDHASH_SZ (1 << UIDHASH_BITS)
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struct user_namespace {
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struct kref kref;
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struct hlist_head uidhash_table[UIDHASH_SZ];
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struct user_struct *creator;
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struct work_struct destroyer;
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unsigned int proc_inum;
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};
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extern struct user_namespace init_user_ns;
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#ifdef CONFIG_USER_NS
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static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
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{
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if (ns)
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kref_get(&ns->kref);
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return ns;
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}
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extern int create_user_ns(struct cred *new);
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extern void free_user_ns(struct kref *kref);
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static inline void put_user_ns(struct user_namespace *ns)
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{
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if (ns)
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kref_put(&ns->kref, free_user_ns);
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}
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uid_t user_ns_map_uid(struct user_namespace *to, const struct cred *cred, uid_t uid);
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gid_t user_ns_map_gid(struct user_namespace *to, const struct cred *cred, gid_t gid);
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#else
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static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
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{
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return &init_user_ns;
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}
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static inline int create_user_ns(struct cred *new)
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{
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return -EINVAL;
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}
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static inline void put_user_ns(struct user_namespace *ns)
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{
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}
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static inline uid_t user_ns_map_uid(struct user_namespace *to,
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const struct cred *cred, uid_t uid)
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{
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return uid;
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}
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static inline gid_t user_ns_map_gid(struct user_namespace *to,
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const struct cred *cred, gid_t gid)
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{
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return gid;
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}
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#endif
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#endif /* _LINUX_USER_H */
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