270 lines
8.0 KiB
C
270 lines
8.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* This is <linux/capability.h>
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*
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* Andrew G. Morgan <morgan@kernel.org>
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* Alexander Kjeldaas <astor@guardian.no>
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* with help from Aleph1, Roland Buresund and Andrew Main.
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*
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* See here for the libcap library ("POSIX draft" compliance):
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*
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* ftp://www.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.6/
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*/
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#ifndef _LINUX_CAPABILITY_H
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#define _LINUX_CAPABILITY_H
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#include <uapi/linux/capability.h>
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#include <linux/uidgid.h>
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#define _KERNEL_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_3
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#define _KERNEL_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_3
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extern int file_caps_enabled;
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typedef struct kernel_cap_struct {
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__u32 cap[_KERNEL_CAPABILITY_U32S];
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} kernel_cap_t;
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/* same as vfs_ns_cap_data but in cpu endian and always filled completely */
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struct cpu_vfs_cap_data {
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__u32 magic_etc;
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kernel_cap_t permitted;
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kernel_cap_t inheritable;
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kuid_t rootid;
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};
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#define _USER_CAP_HEADER_SIZE (sizeof(struct __user_cap_header_struct))
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#define _KERNEL_CAP_T_SIZE (sizeof(kernel_cap_t))
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struct file;
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struct inode;
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struct dentry;
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struct task_struct;
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struct user_namespace;
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extern const kernel_cap_t __cap_empty_set;
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extern const kernel_cap_t __cap_init_eff_set;
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/*
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* Internal kernel functions only
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*/
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#define CAP_FOR_EACH_U32(__capi) \
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for (__capi = 0; __capi < _KERNEL_CAPABILITY_U32S; ++__capi)
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/*
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* CAP_FS_MASK and CAP_NFSD_MASKS:
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*
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* The fs mask is all the privileges that fsuid==0 historically meant.
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* At one time in the past, that included CAP_MKNOD and CAP_LINUX_IMMUTABLE.
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*
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* It has never meant setting security.* and trusted.* xattrs.
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*
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* We could also define fsmask as follows:
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* 1. CAP_FS_MASK is the privilege to bypass all fs-related DAC permissions
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* 2. The security.* and trusted.* xattrs are fs-related MAC permissions
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*/
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# define CAP_FS_MASK_B0 (CAP_TO_MASK(CAP_CHOWN) \
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| CAP_TO_MASK(CAP_MKNOD) \
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| CAP_TO_MASK(CAP_DAC_OVERRIDE) \
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| CAP_TO_MASK(CAP_DAC_READ_SEARCH) \
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| CAP_TO_MASK(CAP_FOWNER) \
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| CAP_TO_MASK(CAP_FSETID))
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# define CAP_FS_MASK_B1 (CAP_TO_MASK(CAP_MAC_OVERRIDE))
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#if _KERNEL_CAPABILITY_U32S != 2
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# error Fix up hand-coded capability macro initializers
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#else /* HAND-CODED capability initializers */
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#define CAP_LAST_U32 ((_KERNEL_CAPABILITY_U32S) - 1)
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#define CAP_LAST_U32_VALID_MASK (CAP_TO_MASK(CAP_LAST_CAP + 1) -1)
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# define CAP_EMPTY_SET ((kernel_cap_t){{ 0, 0 }})
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# define CAP_FULL_SET ((kernel_cap_t){{ ~0, CAP_LAST_U32_VALID_MASK }})
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# define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
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| CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \
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CAP_FS_MASK_B1 } })
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# define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
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| CAP_TO_MASK(CAP_SYS_RESOURCE), \
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CAP_FS_MASK_B1 } })
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#endif /* _KERNEL_CAPABILITY_U32S != 2 */
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# define cap_clear(c) do { (c) = __cap_empty_set; } while (0)
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#define cap_raise(c, flag) ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag))
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#define cap_lower(c, flag) ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag))
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#define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag))
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#define CAP_BOP_ALL(c, a, b, OP) \
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do { \
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unsigned __capi; \
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CAP_FOR_EACH_U32(__capi) { \
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c.cap[__capi] = a.cap[__capi] OP b.cap[__capi]; \
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} \
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} while (0)
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#define CAP_UOP_ALL(c, a, OP) \
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do { \
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unsigned __capi; \
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CAP_FOR_EACH_U32(__capi) { \
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c.cap[__capi] = OP a.cap[__capi]; \
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} \
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} while (0)
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static inline kernel_cap_t cap_combine(const kernel_cap_t a,
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const kernel_cap_t b)
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{
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kernel_cap_t dest;
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CAP_BOP_ALL(dest, a, b, |);
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return dest;
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}
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static inline kernel_cap_t cap_intersect(const kernel_cap_t a,
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const kernel_cap_t b)
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{
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kernel_cap_t dest;
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CAP_BOP_ALL(dest, a, b, &);
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return dest;
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}
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static inline kernel_cap_t cap_drop(const kernel_cap_t a,
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const kernel_cap_t drop)
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{
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kernel_cap_t dest;
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CAP_BOP_ALL(dest, a, drop, &~);
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return dest;
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}
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static inline kernel_cap_t cap_invert(const kernel_cap_t c)
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{
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kernel_cap_t dest;
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CAP_UOP_ALL(dest, c, ~);
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return dest;
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}
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static inline bool cap_isclear(const kernel_cap_t a)
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{
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unsigned __capi;
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CAP_FOR_EACH_U32(__capi) {
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if (a.cap[__capi] != 0)
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return false;
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}
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return true;
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}
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/*
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* Check if "a" is a subset of "set".
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* return true if ALL of the capabilities in "a" are also in "set"
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* cap_issubset(0101, 1111) will return true
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* return false if ANY of the capabilities in "a" are not in "set"
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* cap_issubset(1111, 0101) will return false
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*/
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static inline bool cap_issubset(const kernel_cap_t a, const kernel_cap_t set)
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{
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kernel_cap_t dest;
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dest = cap_drop(a, set);
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return cap_isclear(dest);
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}
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/* Used to decide between falling back on the old suser() or fsuser(). */
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static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a)
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{
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const kernel_cap_t __cap_fs_set = CAP_FS_SET;
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return cap_drop(a, __cap_fs_set);
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}
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static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a,
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const kernel_cap_t permitted)
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{
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const kernel_cap_t __cap_fs_set = CAP_FS_SET;
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return cap_combine(a,
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cap_intersect(permitted, __cap_fs_set));
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}
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static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a)
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{
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const kernel_cap_t __cap_fs_set = CAP_NFSD_SET;
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return cap_drop(a, __cap_fs_set);
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}
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static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a,
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const kernel_cap_t permitted)
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{
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const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET;
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return cap_combine(a,
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cap_intersect(permitted, __cap_nfsd_set));
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}
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#ifdef CONFIG_MULTIUSER
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extern bool has_capability(struct task_struct *t, int cap);
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extern bool has_ns_capability(struct task_struct *t,
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struct user_namespace *ns, int cap);
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extern bool has_capability_noaudit(struct task_struct *t, int cap);
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extern bool has_ns_capability_noaudit(struct task_struct *t,
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struct user_namespace *ns, int cap);
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extern bool capable(int cap);
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extern bool ns_capable(struct user_namespace *ns, int cap);
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extern bool ns_capable_noaudit(struct user_namespace *ns, int cap);
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extern bool ns_capable_setid(struct user_namespace *ns, int cap);
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#else
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static inline bool has_capability(struct task_struct *t, int cap)
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{
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return true;
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}
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static inline bool has_ns_capability(struct task_struct *t,
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struct user_namespace *ns, int cap)
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{
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return true;
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}
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static inline bool has_capability_noaudit(struct task_struct *t, int cap)
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{
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return true;
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}
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static inline bool has_ns_capability_noaudit(struct task_struct *t,
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struct user_namespace *ns, int cap)
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{
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return true;
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}
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static inline bool capable(int cap)
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{
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return true;
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}
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static inline bool ns_capable(struct user_namespace *ns, int cap)
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{
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return true;
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}
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static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap)
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{
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return true;
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}
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static inline bool ns_capable_setid(struct user_namespace *ns, int cap)
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{
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return true;
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}
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#endif /* CONFIG_MULTIUSER */
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extern bool privileged_wrt_inode_uidgid(struct user_namespace *ns, const struct inode *inode);
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extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap);
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extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
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extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns);
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static inline bool perfmon_capable(void)
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{
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return capable(CAP_PERFMON) || capable(CAP_SYS_ADMIN);
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}
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static inline bool bpf_capable(void)
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{
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return capable(CAP_BPF) || capable(CAP_SYS_ADMIN);
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}
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/* audit system wants to get cap info from files as well */
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extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
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extern int cap_convert_nscap(struct dentry *dentry, const void **ivalue, size_t size);
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#endif /* !_LINUX_CAPABILITY_H */
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