1/* 2 * This is <linux/capability.h> 3 * 4 * Andrew G. Morgan <morgan@kernel.org> 5 * Alexander Kjeldaas <astor@guardian.no> 6 * with help from Aleph1, Roland Buresund and Andrew Main. 7 * 8 * See here for the libcap library ("POSIX draft" compliance): 9 * 10 * ftp://www.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.6/ 11 */ 12#ifndef _LINUX_CAPABILITY_H 13#define _LINUX_CAPABILITY_H 14 15#include <uapi/linux/capability.h> 16 17 18#define _KERNEL_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_3 19#define _KERNEL_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_3 20 21extern int file_caps_enabled; 22 23typedef struct kernel_cap_struct { 24 __u32 cap[_KERNEL_CAPABILITY_U32S]; 25} kernel_cap_t; 26 27/* exact same as vfs_cap_data but in cpu endian and always filled completely */ 28struct cpu_vfs_cap_data { 29 __u32 magic_etc; 30 kernel_cap_t permitted; 31 kernel_cap_t inheritable; 32}; 33 34#define _USER_CAP_HEADER_SIZE (sizeof(struct __user_cap_header_struct)) 35#define _KERNEL_CAP_T_SIZE (sizeof(kernel_cap_t)) 36 37 38struct file; 39struct inode; 40struct dentry; 41struct user_namespace; 42 43struct user_namespace *current_user_ns(void); 44 45extern const kernel_cap_t __cap_empty_set; 46extern const kernel_cap_t __cap_init_eff_set; 47 48/* 49 * Internal kernel functions only 50 */ 51 52#define CAP_FOR_EACH_U32(__capi) \ 53 for (__capi = 0; __capi < _KERNEL_CAPABILITY_U32S; ++__capi) 54 55/* 56 * CAP_FS_MASK and CAP_NFSD_MASKS: 57 * 58 * The fs mask is all the privileges that fsuid==0 historically meant. 59 * At one time in the past, that included CAP_MKNOD and CAP_LINUX_IMMUTABLE. 60 * 61 * It has never meant setting security.* and trusted.* xattrs. 62 * 63 * We could also define fsmask as follows: 64 * 1. CAP_FS_MASK is the privilege to bypass all fs-related DAC permissions 65 * 2. The security.* and trusted.* xattrs are fs-related MAC permissions 66 */ 67 68# define CAP_FS_MASK_B0 (CAP_TO_MASK(CAP_CHOWN) \ 69 | CAP_TO_MASK(CAP_MKNOD) \ 70 | CAP_TO_MASK(CAP_DAC_OVERRIDE) \ 71 | CAP_TO_MASK(CAP_DAC_READ_SEARCH) \ 72 | CAP_TO_MASK(CAP_FOWNER) \ 73 | CAP_TO_MASK(CAP_FSETID)) 74 75# define CAP_FS_MASK_B1 (CAP_TO_MASK(CAP_MAC_OVERRIDE)) 76 77#if _KERNEL_CAPABILITY_U32S != 2 78# error Fix up hand-coded capability macro initializers 79#else /* HAND-CODED capability initializers */ 80 81#define CAP_LAST_U32 ((_KERNEL_CAPABILITY_U32S) - 1) 82#define CAP_LAST_U32_VALID_MASK (CAP_TO_MASK(CAP_LAST_CAP + 1) -1) 83 84# define CAP_EMPTY_SET ((kernel_cap_t){{ 0, 0 }}) 85# define CAP_FULL_SET ((kernel_cap_t){{ ~0, CAP_LAST_U32_VALID_MASK }}) 86# define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \ 87 | CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \ 88 CAP_FS_MASK_B1 } }) 89# define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \ 90 | CAP_TO_MASK(CAP_SYS_RESOURCE), \ 91 CAP_FS_MASK_B1 } }) 92 93#endif /* _KERNEL_CAPABILITY_U32S != 2 */ 94 95# define cap_clear(c) do { (c) = __cap_empty_set; } while (0) 96 97#define cap_raise(c, flag) ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag)) 98#define cap_lower(c, flag) ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag)) 99#define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag)) 100 101#define CAP_BOP_ALL(c, a, b, OP) \ 102do { \ 103 unsigned __capi; \ 104 CAP_FOR_EACH_U32(__capi) { \ 105 c.cap[__capi] = a.cap[__capi] OP b.cap[__capi]; \ 106 } \ 107} while (0) 108 109#define CAP_UOP_ALL(c, a, OP) \ 110do { \ 111 unsigned __capi; \ 112 CAP_FOR_EACH_U32(__capi) { \ 113 c.cap[__capi] = OP a.cap[__capi]; \ 114 } \ 115} while (0) 116 117static inline kernel_cap_t cap_combine(const kernel_cap_t a, 118 const kernel_cap_t b) 119{ 120 kernel_cap_t dest; 121 CAP_BOP_ALL(dest, a, b, |); 122 return dest; 123} 124 125static inline kernel_cap_t cap_intersect(const kernel_cap_t a, 126 const kernel_cap_t b) 127{ 128 kernel_cap_t dest; 129 CAP_BOP_ALL(dest, a, b, &); 130 return dest; 131} 132 133static inline kernel_cap_t cap_drop(const kernel_cap_t a, 134 const kernel_cap_t drop) 135{ 136 kernel_cap_t dest; 137 CAP_BOP_ALL(dest, a, drop, &~); 138 return dest; 139} 140 141static inline kernel_cap_t cap_invert(const kernel_cap_t c) 142{ 143 kernel_cap_t dest; 144 CAP_UOP_ALL(dest, c, ~); 145 return dest; 146} 147 148static inline int cap_isclear(const kernel_cap_t a) 149{ 150 unsigned __capi; 151 CAP_FOR_EACH_U32(__capi) { 152 if (a.cap[__capi] != 0) 153 return 0; 154 } 155 return 1; 156} 157 158/* 159 * Check if "a" is a subset of "set". 160 * return 1 if ALL of the capabilities in "a" are also in "set" 161 * cap_issubset(0101, 1111) will return 1 162 * return 0 if ANY of the capabilities in "a" are not in "set" 163 * cap_issubset(1111, 0101) will return 0 164 */ 165static inline int cap_issubset(const kernel_cap_t a, const kernel_cap_t set) 166{ 167 kernel_cap_t dest; 168 dest = cap_drop(a, set); 169 return cap_isclear(dest); 170} 171 172/* Used to decide between falling back on the old suser() or fsuser(). */ 173 174static inline int cap_is_fs_cap(int cap) 175{ 176 const kernel_cap_t __cap_fs_set = CAP_FS_SET; 177 return !!(CAP_TO_MASK(cap) & __cap_fs_set.cap[CAP_TO_INDEX(cap)]); 178} 179 180static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a) 181{ 182 const kernel_cap_t __cap_fs_set = CAP_FS_SET; 183 return cap_drop(a, __cap_fs_set); 184} 185 186static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a, 187 const kernel_cap_t permitted) 188{ 189 const kernel_cap_t __cap_fs_set = CAP_FS_SET; 190 return cap_combine(a, 191 cap_intersect(permitted, __cap_fs_set)); 192} 193 194static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a) 195{ 196 const kernel_cap_t __cap_fs_set = CAP_NFSD_SET; 197 return cap_drop(a, __cap_fs_set); 198} 199 200static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a, 201 const kernel_cap_t permitted) 202{ 203 const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET; 204 return cap_combine(a, 205 cap_intersect(permitted, __cap_nfsd_set)); 206} 207 208#ifdef CONFIG_MULTIUSER 209extern bool has_capability(struct task_struct *t, int cap); 210extern bool has_ns_capability(struct task_struct *t, 211 struct user_namespace *ns, int cap); 212extern bool has_capability_noaudit(struct task_struct *t, int cap); 213extern bool has_ns_capability_noaudit(struct task_struct *t, 214 struct user_namespace *ns, int cap); 215extern bool capable(int cap); 216extern bool ns_capable(struct user_namespace *ns, int cap); 217#else 218static inline bool has_capability(struct task_struct *t, int cap) 219{ 220 return true; 221} 222static inline bool has_ns_capability(struct task_struct *t, 223 struct user_namespace *ns, int cap) 224{ 225 return true; 226} 227static inline bool has_capability_noaudit(struct task_struct *t, int cap) 228{ 229 return true; 230} 231static inline bool has_ns_capability_noaudit(struct task_struct *t, 232 struct user_namespace *ns, int cap) 233{ 234 return true; 235} 236static inline bool capable(int cap) 237{ 238 return true; 239} 240static inline bool ns_capable(struct user_namespace *ns, int cap) 241{ 242 return true; 243} 244#endif /* CONFIG_MULTIUSER */ 245extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap); 246extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap); 247 248/* audit system wants to get cap info from files as well */ 249extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps); 250 251#endif /* !_LINUX_CAPABILITY_H */ 252