2011-11-14 15:29:51 -07:00
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#ifndef _LINUX_UIDGID_H
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#define _LINUX_UIDGID_H
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/*
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* A set of types for the internal kernel types representing uids and gids.
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*
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* The types defined in this header allow distinguishing which uids and gids in
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* the kernel are values used by userspace and which uid and gid values are
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* the internal kernel values. With the addition of user namespaces the values
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* can be different. Using the type system makes it possible for the compiler
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* to detect when we overlook these differences.
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*
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*/
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#include <linux/types.h>
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#include <linux/highuid.h>
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struct user_namespace;
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extern struct user_namespace init_user_ns;
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typedef struct {
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uid_t val;
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} kuid_t;
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typedef struct {
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gid_t val;
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} kgid_t;
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#define KUIDT_INIT(value) (kuid_t){ value }
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#define KGIDT_INIT(value) (kgid_t){ value }
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kernel: conditionally support non-root users, groups and capabilities
There are a lot of embedded systems that run most or all of their
functionality in init, running as root:root. For these systems,
supporting multiple users is not necessary.
This patch adds a new symbol, CONFIG_MULTIUSER, that makes support for
non-root users, non-root groups, and capabilities optional. It is enabled
under CONFIG_EXPERT menu.
When this symbol is not defined, UID and GID are zero in any possible case
and processes always have all capabilities.
The following syscalls are compiled out: setuid, setregid, setgid,
setreuid, setresuid, getresuid, setresgid, getresgid, setgroups,
getgroups, setfsuid, setfsgid, capget, capset.
Also, groups.c is compiled out completely.
In kernel/capability.c, capable function was moved in order to avoid
adding two ifdef blocks.
This change saves about 25 KB on a defconfig build. The most minimal
kernels have total text sizes in the high hundreds of kB rather than
low MB. (The 25k goes down a bit with allnoconfig, but not that much.
The kernel was booted in Qemu. All the common functionalities work.
Adding users/groups is not possible, failing with -ENOSYS.
Bloat-o-meter output:
add/remove: 7/87 grow/shrink: 19/397 up/down: 1675/-26325 (-24650)
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Iulia Manda <iulia.manda21@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15 17:16:41 -06:00
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#ifdef CONFIG_MULTIUSER
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2011-11-14 15:29:51 -07:00
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static inline uid_t __kuid_val(kuid_t uid)
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{
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return uid.val;
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}
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static inline gid_t __kgid_val(kgid_t gid)
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{
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return gid.val;
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}
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kernel: conditionally support non-root users, groups and capabilities
There are a lot of embedded systems that run most or all of their
functionality in init, running as root:root. For these systems,
supporting multiple users is not necessary.
This patch adds a new symbol, CONFIG_MULTIUSER, that makes support for
non-root users, non-root groups, and capabilities optional. It is enabled
under CONFIG_EXPERT menu.
When this symbol is not defined, UID and GID are zero in any possible case
and processes always have all capabilities.
The following syscalls are compiled out: setuid, setregid, setgid,
setreuid, setresuid, getresuid, setresgid, getresgid, setgroups,
getgroups, setfsuid, setfsgid, capget, capset.
Also, groups.c is compiled out completely.
In kernel/capability.c, capable function was moved in order to avoid
adding two ifdef blocks.
This change saves about 25 KB on a defconfig build. The most minimal
kernels have total text sizes in the high hundreds of kB rather than
low MB. (The 25k goes down a bit with allnoconfig, but not that much.
The kernel was booted in Qemu. All the common functionalities work.
Adding users/groups is not possible, failing with -ENOSYS.
Bloat-o-meter output:
add/remove: 7/87 grow/shrink: 19/397 up/down: 1675/-26325 (-24650)
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Iulia Manda <iulia.manda21@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15 17:16:41 -06:00
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#else
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static inline uid_t __kuid_val(kuid_t uid)
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{
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return 0;
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}
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static inline gid_t __kgid_val(kgid_t gid)
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{
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return 0;
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}
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#endif
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2011-11-14 15:29:51 -07:00
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#define GLOBAL_ROOT_UID KUIDT_INIT(0)
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#define GLOBAL_ROOT_GID KGIDT_INIT(0)
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#define INVALID_UID KUIDT_INIT(-1)
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#define INVALID_GID KGIDT_INIT(-1)
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static inline bool uid_eq(kuid_t left, kuid_t right)
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{
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return __kuid_val(left) == __kuid_val(right);
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}
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static inline bool gid_eq(kgid_t left, kgid_t right)
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{
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return __kgid_val(left) == __kgid_val(right);
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}
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static inline bool uid_gt(kuid_t left, kuid_t right)
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{
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return __kuid_val(left) > __kuid_val(right);
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}
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static inline bool gid_gt(kgid_t left, kgid_t right)
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{
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return __kgid_val(left) > __kgid_val(right);
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}
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static inline bool uid_gte(kuid_t left, kuid_t right)
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{
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return __kuid_val(left) >= __kuid_val(right);
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}
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static inline bool gid_gte(kgid_t left, kgid_t right)
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{
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return __kgid_val(left) >= __kgid_val(right);
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}
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static inline bool uid_lt(kuid_t left, kuid_t right)
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{
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return __kuid_val(left) < __kuid_val(right);
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}
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static inline bool gid_lt(kgid_t left, kgid_t right)
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{
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return __kgid_val(left) < __kgid_val(right);
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}
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static inline bool uid_lte(kuid_t left, kuid_t right)
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{
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return __kuid_val(left) <= __kuid_val(right);
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}
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static inline bool gid_lte(kgid_t left, kgid_t right)
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{
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return __kgid_val(left) <= __kgid_val(right);
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}
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static inline bool uid_valid(kuid_t uid)
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{
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uidgid: make uid_valid and gid_valid work with !CONFIG_MULTIUSER
{u,g}id_valid call {u,g}id_eq, which calls __k{u,g}id_val on both
arguments and compares. With !CONFIG_MULTIUSER, __k{u,g}id_val return a
constant 0, which makes {u,g}id_valid always return false. Change
{u,g}id_valid to compare their argument against -1 instead. That produces
identical results in the normal CONFIG_MULTIUSER=y case, but with
!CONFIG_MULTIUSER will make {u,g}id_valid constant-fold into "return
true;" rather than "return false;".
This fixes uses of devpts without CONFIG_MULTIUSER.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>,
Cc: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-05-14 16:17:01 -06:00
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return __kuid_val(uid) != (uid_t) -1;
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2011-11-14 15:29:51 -07:00
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}
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static inline bool gid_valid(kgid_t gid)
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{
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uidgid: make uid_valid and gid_valid work with !CONFIG_MULTIUSER
{u,g}id_valid call {u,g}id_eq, which calls __k{u,g}id_val on both
arguments and compares. With !CONFIG_MULTIUSER, __k{u,g}id_val return a
constant 0, which makes {u,g}id_valid always return false. Change
{u,g}id_valid to compare their argument against -1 instead. That produces
identical results in the normal CONFIG_MULTIUSER=y case, but with
!CONFIG_MULTIUSER will make {u,g}id_valid constant-fold into "return
true;" rather than "return false;".
This fixes uses of devpts without CONFIG_MULTIUSER.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>,
Cc: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-05-14 16:17:01 -06:00
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return __kgid_val(gid) != (gid_t) -1;
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2011-11-14 15:29:51 -07:00
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}
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2011-11-17 01:11:58 -07:00
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#ifdef CONFIG_USER_NS
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extern kuid_t make_kuid(struct user_namespace *from, uid_t uid);
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extern kgid_t make_kgid(struct user_namespace *from, gid_t gid);
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extern uid_t from_kuid(struct user_namespace *to, kuid_t uid);
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extern gid_t from_kgid(struct user_namespace *to, kgid_t gid);
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extern uid_t from_kuid_munged(struct user_namespace *to, kuid_t uid);
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extern gid_t from_kgid_munged(struct user_namespace *to, kgid_t gid);
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static inline bool kuid_has_mapping(struct user_namespace *ns, kuid_t uid)
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{
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return from_kuid(ns, uid) != (uid_t) -1;
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}
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static inline bool kgid_has_mapping(struct user_namespace *ns, kgid_t gid)
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{
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return from_kgid(ns, gid) != (gid_t) -1;
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}
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#else
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2011-11-14 15:29:51 -07:00
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static inline kuid_t make_kuid(struct user_namespace *from, uid_t uid)
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{
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return KUIDT_INIT(uid);
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}
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static inline kgid_t make_kgid(struct user_namespace *from, gid_t gid)
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{
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return KGIDT_INIT(gid);
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}
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static inline uid_t from_kuid(struct user_namespace *to, kuid_t kuid)
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{
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return __kuid_val(kuid);
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}
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static inline gid_t from_kgid(struct user_namespace *to, kgid_t kgid)
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{
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return __kgid_val(kgid);
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}
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static inline uid_t from_kuid_munged(struct user_namespace *to, kuid_t kuid)
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{
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uid_t uid = from_kuid(to, kuid);
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if (uid == (uid_t)-1)
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uid = overflowuid;
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return uid;
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}
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static inline gid_t from_kgid_munged(struct user_namespace *to, kgid_t kgid)
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{
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gid_t gid = from_kgid(to, kgid);
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if (gid == (gid_t)-1)
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gid = overflowgid;
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return gid;
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}
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static inline bool kuid_has_mapping(struct user_namespace *ns, kuid_t uid)
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{
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2016-06-27 14:52:48 -06:00
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return uid_valid(uid);
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2011-11-14 15:29:51 -07:00
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}
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static inline bool kgid_has_mapping(struct user_namespace *ns, kgid_t gid)
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{
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2016-06-27 14:52:48 -06:00
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return gid_valid(gid);
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2011-11-14 15:29:51 -07:00
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}
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2011-11-17 01:11:58 -07:00
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#endif /* CONFIG_USER_NS */
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2011-11-14 15:29:51 -07:00
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#endif /* _LINUX_UIDGID_H */
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