diff options
Diffstat (limited to 'include/linux/capability.h')
| -rw-r--r-- | include/linux/capability.h | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/include/linux/capability.h b/include/linux/capability.h new file mode 100644 index 000000000..65efb74c3 --- /dev/null +++ b/include/linux/capability.h @@ -0,0 +1,281 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * This is <linux/capability.h> + * + * Andrew G. Morgan <morgan@kernel.org> + * Alexander Kjeldaas <astor@guardian.no> + * with help from Aleph1, Roland Buresund and Andrew Main. + * + * See here for the libcap library ("POSIX draft" compliance): + * + * ftp://www.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.6/ + */ +#ifndef _LINUX_CAPABILITY_H +#define _LINUX_CAPABILITY_H + +#include <uapi/linux/capability.h> +#include <linux/uidgid.h> + +#define _KERNEL_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_3 +#define _KERNEL_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_3 + +extern int file_caps_enabled; + +typedef struct kernel_cap_struct { + __u32 cap[_KERNEL_CAPABILITY_U32S]; +} kernel_cap_t; + +/* same as vfs_ns_cap_data but in cpu endian and always filled completely */ +struct cpu_vfs_cap_data { + __u32 magic_etc; + kernel_cap_t permitted; + kernel_cap_t inheritable; + kuid_t rootid; +}; + +#define _USER_CAP_HEADER_SIZE (sizeof(struct __user_cap_header_struct)) +#define _KERNEL_CAP_T_SIZE (sizeof(kernel_cap_t)) + + +struct file; +struct inode; +struct dentry; +struct task_struct; +struct user_namespace; + +extern const kernel_cap_t __cap_empty_set; +extern const kernel_cap_t __cap_init_eff_set; + +/* + * Internal kernel functions only + */ + +#define CAP_FOR_EACH_U32(__capi) \ + for (__capi = 0; __capi < _KERNEL_CAPABILITY_U32S; ++__capi) + +/* + * CAP_FS_MASK and CAP_NFSD_MASKS: + * + * The fs mask is all the privileges that fsuid==0 historically meant. + * At one time in the past, that included CAP_MKNOD and CAP_LINUX_IMMUTABLE. + * + * It has never meant setting security.* and trusted.* xattrs. + * + * We could also define fsmask as follows: + * 1. CAP_FS_MASK is the privilege to bypass all fs-related DAC permissions + * 2. The security.* and trusted.* xattrs are fs-related MAC permissions + */ + +# define CAP_FS_MASK_B0 (CAP_TO_MASK(CAP_CHOWN) \ + | CAP_TO_MASK(CAP_MKNOD) \ + | CAP_TO_MASK(CAP_DAC_OVERRIDE) \ + | CAP_TO_MASK(CAP_DAC_READ_SEARCH) \ + | CAP_TO_MASK(CAP_FOWNER) \ + | CAP_TO_MASK(CAP_FSETID)) + +# define CAP_FS_MASK_B1 (CAP_TO_MASK(CAP_MAC_OVERRIDE)) + +#if _KERNEL_CAPABILITY_U32S != 2 +# error Fix up hand-coded capability macro initializers +#else /* HAND-CODED capability initializers */ + +#define CAP_LAST_U32 ((_KERNEL_CAPABILITY_U32S) - 1) +#define CAP_LAST_U32_VALID_MASK (CAP_TO_MASK(CAP_LAST_CAP + 1) -1) + +# define CAP_EMPTY_SET ((kernel_cap_t){{ 0, 0 }}) +# define CAP_FULL_SET ((kernel_cap_t){{ ~0, CAP_LAST_U32_VALID_MASK }}) +# define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \ + | CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \ + CAP_FS_MASK_B1 } }) +# define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \ + | CAP_TO_MASK(CAP_SYS_RESOURCE), \ + CAP_FS_MASK_B1 } }) + +#endif /* _KERNEL_CAPABILITY_U32S != 2 */ + +# define cap_clear(c) do { (c) = __cap_empty_set; } while (0) + +#define cap_raise(c, flag) ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag)) +#define cap_lower(c, flag) ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag)) +#define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag)) + +#define CAP_BOP_ALL(c, a, b, OP) \ +do { \ + unsigned __capi; \ + CAP_FOR_EACH_U32(__capi) { \ + c.cap[__capi] = a.cap[__capi] OP b.cap[__capi]; \ + } \ +} while (0) + +#define CAP_UOP_ALL(c, a, OP) \ +do { \ + unsigned __capi; \ + CAP_FOR_EACH_U32(__capi) { \ + c.cap[__capi] = OP a.cap[__capi]; \ + } \ +} while (0) + +static inline kernel_cap_t cap_combine(const kernel_cap_t a, + const kernel_cap_t b) +{ + kernel_cap_t dest; + CAP_BOP_ALL(dest, a, b, |); + return dest; +} + +static inline kernel_cap_t cap_intersect(const kernel_cap_t a, + const kernel_cap_t b) +{ + kernel_cap_t dest; + CAP_BOP_ALL(dest, a, b, &); + return dest; +} + +static inline kernel_cap_t cap_drop(const kernel_cap_t a, + const kernel_cap_t drop) +{ + kernel_cap_t dest; + CAP_BOP_ALL(dest, a, drop, &~); + return dest; +} + +static inline kernel_cap_t cap_invert(const kernel_cap_t c) +{ + kernel_cap_t dest; + CAP_UOP_ALL(dest, c, ~); + return dest; +} + +static inline bool cap_isclear(const kernel_cap_t a) +{ + unsigned __capi; + CAP_FOR_EACH_U32(__capi) { + if (a.cap[__capi] != 0) + return false; + } + return true; +} + +/* + * Check if "a" is a subset of "set". + * return true if ALL of the capabilities in "a" are also in "set" + * cap_issubset(0101, 1111) will return true + * return false if ANY of the capabilities in "a" are not in "set" + * cap_issubset(1111, 0101) will return false + */ +static inline bool cap_issubset(const kernel_cap_t a, const kernel_cap_t set) +{ + kernel_cap_t dest; + dest = cap_drop(a, set); + return cap_isclear(dest); +} + +/* Used to decide between falling back on the old suser() or fsuser(). */ + +static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a) +{ + const kernel_cap_t __cap_fs_set = CAP_FS_SET; + return cap_drop(a, __cap_fs_set); +} + +static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a, + const kernel_cap_t permitted) +{ + const kernel_cap_t __cap_fs_set = CAP_FS_SET; + return cap_combine(a, + cap_intersect(permitted, __cap_fs_set)); +} + +static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a) +{ + const kernel_cap_t __cap_fs_set = CAP_NFSD_SET; + return cap_drop(a, __cap_fs_set); +} + +static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a, + const kernel_cap_t permitted) +{ + const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET; + return cap_combine(a, + cap_intersect(permitted, __cap_nfsd_set)); +} + +#ifdef CONFIG_MULTIUSER +extern bool has_capability(struct task_struct *t, int cap); +extern bool has_ns_capability(struct task_struct *t, + struct user_namespace *ns, int cap); +extern bool has_capability_noaudit(struct task_struct *t, int cap); +extern bool has_ns_capability_noaudit(struct task_struct *t, + struct user_namespace *ns, int cap); +extern bool capable(int cap); +extern bool ns_capable(struct user_namespace *ns, int cap); +extern bool ns_capable_noaudit(struct user_namespace *ns, int cap); +extern bool ns_capable_setid(struct user_namespace *ns, int cap); +#else +static inline bool has_capability(struct task_struct *t, int cap) +{ + return true; +} +static inline bool has_ns_capability(struct task_struct *t, + struct user_namespace *ns, int cap) +{ + return true; +} +static inline bool has_capability_noaudit(struct task_struct *t, int cap) +{ + return true; +} +static inline bool has_ns_capability_noaudit(struct task_struct *t, + struct user_namespace *ns, int cap) +{ + return true; +} +static inline bool capable(int cap) +{ + return true; +} +static inline bool ns_capable(struct user_namespace *ns, int cap) +{ + return true; +} +static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap) +{ + return true; +} +static inline bool ns_capable_setid(struct user_namespace *ns, int cap) +{ + return true; +} +#endif /* CONFIG_MULTIUSER */ +bool privileged_wrt_inode_uidgid(struct user_namespace *ns, + struct user_namespace *mnt_userns, + const struct inode *inode); +bool capable_wrt_inode_uidgid(struct user_namespace *mnt_userns, + const struct inode *inode, int cap); +extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap); +extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns); +static inline bool perfmon_capable(void) +{ + return capable(CAP_PERFMON) || capable(CAP_SYS_ADMIN); +} + +static inline bool bpf_capable(void) +{ + return capable(CAP_BPF) || capable(CAP_SYS_ADMIN); +} + +static inline bool checkpoint_restore_ns_capable(struct user_namespace *ns) +{ + return ns_capable(ns, CAP_CHECKPOINT_RESTORE) || + ns_capable(ns, CAP_SYS_ADMIN); +} + +/* audit system wants to get cap info from files as well */ +int get_vfs_caps_from_disk(struct user_namespace *mnt_userns, + const struct dentry *dentry, + struct cpu_vfs_cap_data *cpu_caps); + +int cap_convert_nscap(struct user_namespace *mnt_userns, struct dentry *dentry, + const void **ivalue, size_t size); + +#endif /* !_LINUX_CAPABILITY_H */ |