1 /* 2 * This is <linux/capability.h> 3 * 4 * Andrew G. Morgan <[email protected]> 5 * Alexander Kjeldaas <[email protected]> 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 21 extern int file_caps_enabled; 22 23 typedef 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 */ 28 struct 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 38 struct file; 39 struct inode; 40 struct dentry; 41 struct user_namespace; 42 43 struct user_namespace *current_user_ns(void); 44 45 extern const kernel_cap_t __cap_empty_set; 46 extern 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) \ 102 do { \ 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) \ 110 do { \ 111 unsigned __capi; \ 112 CAP_FOR_EACH_U32(__capi) { \ 113 c.cap[__capi] = OP a.cap[__capi]; \ 114 } \ 115 } while (0) 116 117 static 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 } 124 125 static 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 } 132 133 static 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 } 140 141 static 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 } 147 148 static 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 */ 165 static 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(). */ 173 174 static 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 } 179 180 static 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 } 185 186 static 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 } 193 194 static 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 } 199 200 static 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 209 extern bool has_capability(struct task_struct *t, int cap); 210 extern bool has_ns_capability(struct task_struct *t, 211 struct user_namespace *ns, int cap); 212 extern bool has_capability_noaudit(struct task_struct *t, int cap); 213 extern bool has_ns_capability_noaudit(struct task_struct *t, 214 struct user_namespace *ns, int cap); 215 extern bool capable(int cap); 216 extern bool ns_capable(struct user_namespace *ns, int cap); 217 #else 218 static inline bool has_capability(struct task_struct *t, int cap) 219 { 220 return true; 221 } 222 static inline bool has_ns_capability(struct task_struct *t, 223 struct user_namespace *ns, int cap) 224 { 225 return true; 226 } 227 static inline bool has_capability_noaudit(struct task_struct *t, int cap) 228 { 229 return true; 230 } 231 static inline bool has_ns_capability_noaudit(struct task_struct *t, 232 struct user_namespace *ns, int cap) 233 { 234 return true; 235 } 236 static inline bool capable(int cap) 237 { 238 return true; 239 } 240 static inline bool ns_capable(struct user_namespace *ns, int cap) 241 { 242 return true; 243 } 244 #endif /* CONFIG_MULTIUSER */ 245 extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap); 246 extern 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 */ 249 extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps); 250 251 #endif /* !_LINUX_CAPABILITY_H */ 252