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