1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * This is <linux/capability.h> 4 * 5 * Andrew G. Morgan <[email protected]> 6 * Alexander Kjeldaas <[email protected]> 7 * with help from Aleph1, Roland Buresund and Andrew Main. 8 * 9 * See here for the libcap library ("POSIX draft" compliance): 10 * 11 * ftp://www.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.6/ 12 */ 13 #ifndef _LINUX_CAPABILITY_H 14 #define _LINUX_CAPABILITY_H 15 16 #include <uapi/linux/capability.h> 17 #include <linux/uidgid.h> 18 19 #define _KERNEL_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_3 20 #define _KERNEL_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_3 21 22 extern int file_caps_enabled; 23 24 typedef struct kernel_cap_struct { 25 __u32 cap[_KERNEL_CAPABILITY_U32S]; 26 } kernel_cap_t; 27 28 /* same as vfs_ns_cap_data but in cpu endian and always filled completely */ 29 struct cpu_vfs_cap_data { 30 __u32 magic_etc; 31 kernel_cap_t permitted; 32 kernel_cap_t inheritable; 33 kuid_t rootid; 34 }; 35 36 #define _USER_CAP_HEADER_SIZE (sizeof(struct __user_cap_header_struct)) 37 #define _KERNEL_CAP_T_SIZE (sizeof(kernel_cap_t)) 38 39 40 struct file; 41 struct inode; 42 struct dentry; 43 struct task_struct; 44 struct user_namespace; 45 struct mnt_idmap; 46 47 extern const kernel_cap_t __cap_empty_set; 48 extern const kernel_cap_t __cap_init_eff_set; 49 50 /* 51 * Internal kernel functions only 52 */ 53 54 #define CAP_FOR_EACH_U32(__capi) \ 55 for (__capi = 0; __capi < _KERNEL_CAPABILITY_U32S; ++__capi) 56 57 /* 58 * CAP_FS_MASK and CAP_NFSD_MASKS: 59 * 60 * The fs mask is all the privileges that fsuid==0 historically meant. 61 * At one time in the past, that included CAP_MKNOD and CAP_LINUX_IMMUTABLE. 62 * 63 * It has never meant setting security.* and trusted.* xattrs. 64 * 65 * We could also define fsmask as follows: 66 * 1. CAP_FS_MASK is the privilege to bypass all fs-related DAC permissions 67 * 2. The security.* and trusted.* xattrs are fs-related MAC permissions 68 */ 69 70 # define CAP_FS_MASK_B0 (CAP_TO_MASK(CAP_CHOWN) \ 71 | CAP_TO_MASK(CAP_MKNOD) \ 72 | CAP_TO_MASK(CAP_DAC_OVERRIDE) \ 73 | CAP_TO_MASK(CAP_DAC_READ_SEARCH) \ 74 | CAP_TO_MASK(CAP_FOWNER) \ 75 | CAP_TO_MASK(CAP_FSETID)) 76 77 # define CAP_FS_MASK_B1 (CAP_TO_MASK(CAP_MAC_OVERRIDE)) 78 79 #if _KERNEL_CAPABILITY_U32S != 2 80 # error Fix up hand-coded capability macro initializers 81 #else /* HAND-CODED capability initializers */ 82 83 #define CAP_LAST_U32 ((_KERNEL_CAPABILITY_U32S) - 1) 84 #define CAP_LAST_U32_VALID_MASK (CAP_TO_MASK(CAP_LAST_CAP + 1) -1) 85 86 # define CAP_EMPTY_SET ((kernel_cap_t){{ 0, 0 }}) 87 # define CAP_FULL_SET ((kernel_cap_t){{ ~0, CAP_LAST_U32_VALID_MASK }}) 88 # define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \ 89 | CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \ 90 CAP_FS_MASK_B1 } }) 91 # define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \ 92 | CAP_TO_MASK(CAP_SYS_RESOURCE), \ 93 CAP_FS_MASK_B1 } }) 94 95 #endif /* _KERNEL_CAPABILITY_U32S != 2 */ 96 97 # define cap_clear(c) do { (c) = __cap_empty_set; } while (0) 98 99 #define cap_raise(c, flag) ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag)) 100 #define cap_lower(c, flag) ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag)) 101 #define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag)) 102 103 #define CAP_BOP_ALL(c, a, b, OP) \ 104 do { \ 105 unsigned __capi; \ 106 CAP_FOR_EACH_U32(__capi) { \ 107 c.cap[__capi] = a.cap[__capi] OP b.cap[__capi]; \ 108 } \ 109 } while (0) 110 111 #define CAP_UOP_ALL(c, a, OP) \ 112 do { \ 113 unsigned __capi; \ 114 CAP_FOR_EACH_U32(__capi) { \ 115 c.cap[__capi] = OP a.cap[__capi]; \ 116 } \ 117 } while (0) 118 119 static inline kernel_cap_t cap_combine(const kernel_cap_t a, 120 const kernel_cap_t b) 121 { 122 kernel_cap_t dest; 123 CAP_BOP_ALL(dest, a, b, |); 124 return dest; 125 } 126 127 static inline kernel_cap_t cap_intersect(const kernel_cap_t a, 128 const kernel_cap_t b) 129 { 130 kernel_cap_t dest; 131 CAP_BOP_ALL(dest, a, b, &); 132 return dest; 133 } 134 135 static inline kernel_cap_t cap_drop(const kernel_cap_t a, 136 const kernel_cap_t drop) 137 { 138 kernel_cap_t dest; 139 CAP_BOP_ALL(dest, a, drop, &~); 140 return dest; 141 } 142 143 static inline kernel_cap_t cap_invert(const kernel_cap_t c) 144 { 145 kernel_cap_t dest; 146 CAP_UOP_ALL(dest, c, ~); 147 return dest; 148 } 149 150 static inline bool cap_isclear(const kernel_cap_t a) 151 { 152 unsigned __capi; 153 CAP_FOR_EACH_U32(__capi) { 154 if (a.cap[__capi] != 0) 155 return false; 156 } 157 return true; 158 } 159 160 static inline bool cap_isidentical(const kernel_cap_t a, const kernel_cap_t b) 161 { 162 unsigned __capi; 163 CAP_FOR_EACH_U32(__capi) { 164 if (a.cap[__capi] != b.cap[__capi]) 165 return false; 166 } 167 return true; 168 } 169 170 /* 171 * Check if "a" is a subset of "set". 172 * return true if ALL of the capabilities in "a" are also in "set" 173 * cap_issubset(0101, 1111) will return true 174 * return false if ANY of the capabilities in "a" are not in "set" 175 * cap_issubset(1111, 0101) will return false 176 */ 177 static inline bool cap_issubset(const kernel_cap_t a, const kernel_cap_t set) 178 { 179 kernel_cap_t dest; 180 dest = cap_drop(a, set); 181 return cap_isclear(dest); 182 } 183 184 /* Used to decide between falling back on the old suser() or fsuser(). */ 185 186 static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a) 187 { 188 const kernel_cap_t __cap_fs_set = CAP_FS_SET; 189 return cap_drop(a, __cap_fs_set); 190 } 191 192 static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a, 193 const kernel_cap_t permitted) 194 { 195 const kernel_cap_t __cap_fs_set = CAP_FS_SET; 196 return cap_combine(a, 197 cap_intersect(permitted, __cap_fs_set)); 198 } 199 200 static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a) 201 { 202 const kernel_cap_t __cap_fs_set = CAP_NFSD_SET; 203 return cap_drop(a, __cap_fs_set); 204 } 205 206 static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a, 207 const kernel_cap_t permitted) 208 { 209 const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET; 210 return cap_combine(a, 211 cap_intersect(permitted, __cap_nfsd_set)); 212 } 213 214 #ifdef CONFIG_MULTIUSER 215 extern bool has_capability(struct task_struct *t, int cap); 216 extern bool has_ns_capability(struct task_struct *t, 217 struct user_namespace *ns, int cap); 218 extern bool has_capability_noaudit(struct task_struct *t, int cap); 219 extern bool has_ns_capability_noaudit(struct task_struct *t, 220 struct user_namespace *ns, int cap); 221 extern bool capable(int cap); 222 extern bool ns_capable(struct user_namespace *ns, int cap); 223 extern bool ns_capable_noaudit(struct user_namespace *ns, int cap); 224 extern bool ns_capable_setid(struct user_namespace *ns, int cap); 225 #else 226 static inline bool has_capability(struct task_struct *t, int cap) 227 { 228 return true; 229 } 230 static inline bool has_ns_capability(struct task_struct *t, 231 struct user_namespace *ns, int cap) 232 { 233 return true; 234 } 235 static inline bool has_capability_noaudit(struct task_struct *t, int cap) 236 { 237 return true; 238 } 239 static inline bool has_ns_capability_noaudit(struct task_struct *t, 240 struct user_namespace *ns, int cap) 241 { 242 return true; 243 } 244 static inline bool capable(int cap) 245 { 246 return true; 247 } 248 static inline bool ns_capable(struct user_namespace *ns, int cap) 249 { 250 return true; 251 } 252 static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap) 253 { 254 return true; 255 } 256 static inline bool ns_capable_setid(struct user_namespace *ns, int cap) 257 { 258 return true; 259 } 260 #endif /* CONFIG_MULTIUSER */ 261 bool privileged_wrt_inode_uidgid(struct user_namespace *ns, 262 struct mnt_idmap *idmap, 263 const struct inode *inode); 264 bool capable_wrt_inode_uidgid(struct mnt_idmap *idmap, 265 const struct inode *inode, int cap); 266 extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap); 267 extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns); 268 static inline bool perfmon_capable(void) 269 { 270 return capable(CAP_PERFMON) || capable(CAP_SYS_ADMIN); 271 } 272 273 static inline bool bpf_capable(void) 274 { 275 return capable(CAP_BPF) || capable(CAP_SYS_ADMIN); 276 } 277 278 static inline bool checkpoint_restore_ns_capable(struct user_namespace *ns) 279 { 280 return ns_capable(ns, CAP_CHECKPOINT_RESTORE) || 281 ns_capable(ns, CAP_SYS_ADMIN); 282 } 283 284 /* audit system wants to get cap info from files as well */ 285 int get_vfs_caps_from_disk(struct mnt_idmap *idmap, 286 const struct dentry *dentry, 287 struct cpu_vfs_cap_data *cpu_caps); 288 289 int cap_convert_nscap(struct mnt_idmap *idmap, struct dentry *dentry, 290 const void **ivalue, size_t size); 291 292 #endif /* !_LINUX_CAPABILITY_H */ 293