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 task_struct; 42 struct user_namespace; 43 44 extern const kernel_cap_t __cap_empty_set; 45 extern const kernel_cap_t __cap_init_eff_set; 46 47 /* 48 * Internal kernel functions only 49 */ 50 51 #define CAP_FOR_EACH_U32(__capi) \ 52 for (__capi = 0; __capi < _KERNEL_CAPABILITY_U32S; ++__capi) 53 54 /* 55 * CAP_FS_MASK and CAP_NFSD_MASKS: 56 * 57 * The fs mask is all the privileges that fsuid==0 historically meant. 58 * At one time in the past, that included CAP_MKNOD and CAP_LINUX_IMMUTABLE. 59 * 60 * It has never meant setting security.* and trusted.* xattrs. 61 * 62 * We could also define fsmask as follows: 63 * 1. CAP_FS_MASK is the privilege to bypass all fs-related DAC permissions 64 * 2. The security.* and trusted.* xattrs are fs-related MAC permissions 65 */ 66 67 # define CAP_FS_MASK_B0 (CAP_TO_MASK(CAP_CHOWN) \ 68 | CAP_TO_MASK(CAP_MKNOD) \ 69 | CAP_TO_MASK(CAP_DAC_OVERRIDE) \ 70 | CAP_TO_MASK(CAP_DAC_READ_SEARCH) \ 71 | CAP_TO_MASK(CAP_FOWNER) \ 72 | CAP_TO_MASK(CAP_FSETID)) 73 74 # define CAP_FS_MASK_B1 (CAP_TO_MASK(CAP_MAC_OVERRIDE)) 75 76 #if _KERNEL_CAPABILITY_U32S != 2 77 # error Fix up hand-coded capability macro initializers 78 #else /* HAND-CODED capability initializers */ 79 80 #define CAP_LAST_U32 ((_KERNEL_CAPABILITY_U32S) - 1) 81 #define CAP_LAST_U32_VALID_MASK (CAP_TO_MASK(CAP_LAST_CAP + 1) -1) 82 83 # define CAP_EMPTY_SET ((kernel_cap_t){{ 0, 0 }}) 84 # define CAP_FULL_SET ((kernel_cap_t){{ ~0, CAP_LAST_U32_VALID_MASK }}) 85 # define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \ 86 | CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \ 87 CAP_FS_MASK_B1 } }) 88 # define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \ 89 | CAP_TO_MASK(CAP_SYS_RESOURCE), \ 90 CAP_FS_MASK_B1 } }) 91 92 #endif /* _KERNEL_CAPABILITY_U32S != 2 */ 93 94 # define cap_clear(c) do { (c) = __cap_empty_set; } while (0) 95 96 #define cap_raise(c, flag) ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag)) 97 #define cap_lower(c, flag) ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag)) 98 #define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag)) 99 100 #define CAP_BOP_ALL(c, a, b, OP) \ 101 do { \ 102 unsigned __capi; \ 103 CAP_FOR_EACH_U32(__capi) { \ 104 c.cap[__capi] = a.cap[__capi] OP b.cap[__capi]; \ 105 } \ 106 } while (0) 107 108 #define CAP_UOP_ALL(c, a, OP) \ 109 do { \ 110 unsigned __capi; \ 111 CAP_FOR_EACH_U32(__capi) { \ 112 c.cap[__capi] = OP a.cap[__capi]; \ 113 } \ 114 } while (0) 115 116 static inline kernel_cap_t cap_combine(const kernel_cap_t a, 117 const kernel_cap_t b) 118 { 119 kernel_cap_t dest; 120 CAP_BOP_ALL(dest, a, b, |); 121 return dest; 122 } 123 124 static inline kernel_cap_t cap_intersect(const kernel_cap_t a, 125 const kernel_cap_t b) 126 { 127 kernel_cap_t dest; 128 CAP_BOP_ALL(dest, a, b, &); 129 return dest; 130 } 131 132 static inline kernel_cap_t cap_drop(const kernel_cap_t a, 133 const kernel_cap_t drop) 134 { 135 kernel_cap_t dest; 136 CAP_BOP_ALL(dest, a, drop, &~); 137 return dest; 138 } 139 140 static inline kernel_cap_t cap_invert(const kernel_cap_t c) 141 { 142 kernel_cap_t dest; 143 CAP_UOP_ALL(dest, c, ~); 144 return dest; 145 } 146 147 static inline bool cap_isclear(const kernel_cap_t a) 148 { 149 unsigned __capi; 150 CAP_FOR_EACH_U32(__capi) { 151 if (a.cap[__capi] != 0) 152 return false; 153 } 154 return true; 155 } 156 157 /* 158 * Check if "a" is a subset of "set". 159 * return true if ALL of the capabilities in "a" are also in "set" 160 * cap_issubset(0101, 1111) will return true 161 * return false if ANY of the capabilities in "a" are not in "set" 162 * cap_issubset(1111, 0101) will return false 163 */ 164 static inline bool cap_issubset(const kernel_cap_t a, const kernel_cap_t set) 165 { 166 kernel_cap_t dest; 167 dest = cap_drop(a, set); 168 return cap_isclear(dest); 169 } 170 171 /* Used to decide between falling back on the old suser() or fsuser(). */ 172 173 static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a) 174 { 175 const kernel_cap_t __cap_fs_set = CAP_FS_SET; 176 return cap_drop(a, __cap_fs_set); 177 } 178 179 static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a, 180 const kernel_cap_t permitted) 181 { 182 const kernel_cap_t __cap_fs_set = CAP_FS_SET; 183 return cap_combine(a, 184 cap_intersect(permitted, __cap_fs_set)); 185 } 186 187 static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a) 188 { 189 const kernel_cap_t __cap_fs_set = CAP_NFSD_SET; 190 return cap_drop(a, __cap_fs_set); 191 } 192 193 static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a, 194 const kernel_cap_t permitted) 195 { 196 const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET; 197 return cap_combine(a, 198 cap_intersect(permitted, __cap_nfsd_set)); 199 } 200 201 #ifdef CONFIG_MULTIUSER 202 extern bool has_capability(struct task_struct *t, int cap); 203 extern bool has_ns_capability(struct task_struct *t, 204 struct user_namespace *ns, int cap); 205 extern bool has_capability_noaudit(struct task_struct *t, int cap); 206 extern bool has_ns_capability_noaudit(struct task_struct *t, 207 struct user_namespace *ns, int cap); 208 extern bool capable(int cap); 209 extern bool ns_capable(struct user_namespace *ns, int cap); 210 extern bool ns_capable_noaudit(struct user_namespace *ns, int cap); 211 #else 212 static inline bool has_capability(struct task_struct *t, int cap) 213 { 214 return true; 215 } 216 static inline bool has_ns_capability(struct task_struct *t, 217 struct user_namespace *ns, int cap) 218 { 219 return true; 220 } 221 static inline bool has_capability_noaudit(struct task_struct *t, int cap) 222 { 223 return true; 224 } 225 static inline bool has_ns_capability_noaudit(struct task_struct *t, 226 struct user_namespace *ns, int cap) 227 { 228 return true; 229 } 230 static inline bool capable(int cap) 231 { 232 return true; 233 } 234 static inline bool ns_capable(struct user_namespace *ns, int cap) 235 { 236 return true; 237 } 238 static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap) 239 { 240 return true; 241 } 242 #endif /* CONFIG_MULTIUSER */ 243 extern bool privileged_wrt_inode_uidgid(struct user_namespace *ns, const struct inode *inode); 244 extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap); 245 extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap); 246 extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns); 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