1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * This is <linux/capability.h> 4 * 5 * Andrew G. Morgan <morgan@kernel.org> 6 * Alexander Kjeldaas <astor@guardian.no> 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 46 extern const kernel_cap_t __cap_empty_set; 47 extern const kernel_cap_t __cap_init_eff_set; 48 49 /* 50 * Internal kernel functions only 51 */ 52 53 #define CAP_FOR_EACH_U32(__capi) \ 54 for (__capi = 0; __capi < _KERNEL_CAPABILITY_U32S; ++__capi) 55 56 /* 57 * CAP_FS_MASK and CAP_NFSD_MASKS: 58 * 59 * The fs mask is all the privileges that fsuid==0 historically meant. 60 * At one time in the past, that included CAP_MKNOD and CAP_LINUX_IMMUTABLE. 61 * 62 * It has never meant setting security.* and trusted.* xattrs. 63 * 64 * We could also define fsmask as follows: 65 * 1. CAP_FS_MASK is the privilege to bypass all fs-related DAC permissions 66 * 2. The security.* and trusted.* xattrs are fs-related MAC permissions 67 */ 68 69 # define CAP_FS_MASK_B0 (CAP_TO_MASK(CAP_CHOWN) \ 70 | CAP_TO_MASK(CAP_MKNOD) \ 71 | CAP_TO_MASK(CAP_DAC_OVERRIDE) \ 72 | CAP_TO_MASK(CAP_DAC_READ_SEARCH) \ 73 | CAP_TO_MASK(CAP_FOWNER) \ 74 | CAP_TO_MASK(CAP_FSETID)) 75 76 # define CAP_FS_MASK_B1 (CAP_TO_MASK(CAP_MAC_OVERRIDE)) 77 78 #if _KERNEL_CAPABILITY_U32S != 2 79 # error Fix up hand-coded capability macro initializers 80 #else /* HAND-CODED capability initializers */ 81 82 #define CAP_LAST_U32 ((_KERNEL_CAPABILITY_U32S) - 1) 83 #define CAP_LAST_U32_VALID_MASK (CAP_TO_MASK(CAP_LAST_CAP + 1) -1) 84 85 # define CAP_EMPTY_SET ((kernel_cap_t){{ 0, 0 }}) 86 # define CAP_FULL_SET ((kernel_cap_t){{ ~0, CAP_LAST_U32_VALID_MASK }}) 87 # define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \ 88 | CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \ 89 CAP_FS_MASK_B1 } }) 90 # define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \ 91 | CAP_TO_MASK(CAP_SYS_RESOURCE), \ 92 CAP_FS_MASK_B1 } }) 93 94 #endif /* _KERNEL_CAPABILITY_U32S != 2 */ 95 96 # define cap_clear(c) do { (c) = __cap_empty_set; } while (0) 97 98 #define cap_raise(c, flag) ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag)) 99 #define cap_lower(c, flag) ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag)) 100 #define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag)) 101 102 #define CAP_BOP_ALL(c, a, b, OP) \ 103 do { \ 104 unsigned __capi; \ 105 CAP_FOR_EACH_U32(__capi) { \ 106 c.cap[__capi] = a.cap[__capi] OP b.cap[__capi]; \ 107 } \ 108 } while (0) 109 110 #define CAP_UOP_ALL(c, a, OP) \ 111 do { \ 112 unsigned __capi; \ 113 CAP_FOR_EACH_U32(__capi) { \ 114 c.cap[__capi] = OP a.cap[__capi]; \ 115 } \ 116 } while (0) 117 118 static inline kernel_cap_t cap_combine(const kernel_cap_t a, 119 const kernel_cap_t b) 120 { 121 kernel_cap_t dest; 122 CAP_BOP_ALL(dest, a, b, |); 123 return dest; 124 } 125 126 static inline kernel_cap_t cap_intersect(const kernel_cap_t a, 127 const kernel_cap_t b) 128 { 129 kernel_cap_t dest; 130 CAP_BOP_ALL(dest, a, b, &); 131 return dest; 132 } 133 134 static inline kernel_cap_t cap_drop(const kernel_cap_t a, 135 const kernel_cap_t drop) 136 { 137 kernel_cap_t dest; 138 CAP_BOP_ALL(dest, a, drop, &~); 139 return dest; 140 } 141 142 static inline kernel_cap_t cap_invert(const kernel_cap_t c) 143 { 144 kernel_cap_t dest; 145 CAP_UOP_ALL(dest, c, ~); 146 return dest; 147 } 148 149 static inline bool cap_isclear(const kernel_cap_t a) 150 { 151 unsigned __capi; 152 CAP_FOR_EACH_U32(__capi) { 153 if (a.cap[__capi] != 0) 154 return false; 155 } 156 return true; 157 } 158 159 /* 160 * Check if "a" is a subset of "set". 161 * return true if ALL of the capabilities in "a" are also in "set" 162 * cap_issubset(0101, 1111) will return true 163 * return false if ANY of the capabilities in "a" are not in "set" 164 * cap_issubset(1111, 0101) will return false 165 */ 166 static inline bool cap_issubset(const kernel_cap_t a, const kernel_cap_t set) 167 { 168 kernel_cap_t dest; 169 dest = cap_drop(a, set); 170 return cap_isclear(dest); 171 } 172 173 /* Used to decide between falling back on the old suser() or fsuser(). */ 174 175 static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a) 176 { 177 const kernel_cap_t __cap_fs_set = CAP_FS_SET; 178 return cap_drop(a, __cap_fs_set); 179 } 180 181 static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a, 182 const kernel_cap_t permitted) 183 { 184 const kernel_cap_t __cap_fs_set = CAP_FS_SET; 185 return cap_combine(a, 186 cap_intersect(permitted, __cap_fs_set)); 187 } 188 189 static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a) 190 { 191 const kernel_cap_t __cap_fs_set = CAP_NFSD_SET; 192 return cap_drop(a, __cap_fs_set); 193 } 194 195 static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a, 196 const kernel_cap_t permitted) 197 { 198 const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET; 199 return cap_combine(a, 200 cap_intersect(permitted, __cap_nfsd_set)); 201 } 202 203 #ifdef CONFIG_MULTIUSER 204 extern bool has_capability(struct task_struct *t, int cap); 205 extern bool has_ns_capability(struct task_struct *t, 206 struct user_namespace *ns, int cap); 207 extern bool has_capability_noaudit(struct task_struct *t, int cap); 208 extern bool has_ns_capability_noaudit(struct task_struct *t, 209 struct user_namespace *ns, int cap); 210 extern bool capable(int cap); 211 extern bool ns_capable(struct user_namespace *ns, int cap); 212 extern bool ns_capable_noaudit(struct user_namespace *ns, int cap); 213 extern bool ns_capable_setid(struct user_namespace *ns, int cap); 214 #else 215 static inline bool has_capability(struct task_struct *t, int cap) 216 { 217 return true; 218 } 219 static inline bool has_ns_capability(struct task_struct *t, 220 struct user_namespace *ns, int cap) 221 { 222 return true; 223 } 224 static inline bool has_capability_noaudit(struct task_struct *t, int cap) 225 { 226 return true; 227 } 228 static inline bool has_ns_capability_noaudit(struct task_struct *t, 229 struct user_namespace *ns, int cap) 230 { 231 return true; 232 } 233 static inline bool capable(int cap) 234 { 235 return true; 236 } 237 static inline bool ns_capable(struct user_namespace *ns, int cap) 238 { 239 return true; 240 } 241 static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap) 242 { 243 return true; 244 } 245 static inline bool ns_capable_setid(struct user_namespace *ns, int cap) 246 { 247 return true; 248 } 249 #endif /* CONFIG_MULTIUSER */ 250 extern bool privileged_wrt_inode_uidgid(struct user_namespace *ns, const struct inode *inode); 251 extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap); 252 extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap); 253 extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns); 254 static inline bool perfmon_capable(void) 255 { 256 return capable(CAP_PERFMON) || capable(CAP_SYS_ADMIN); 257 } 258 259 static inline bool bpf_capable(void) 260 { 261 return capable(CAP_BPF) || capable(CAP_SYS_ADMIN); 262 } 263 264 static inline bool checkpoint_restore_ns_capable(struct user_namespace *ns) 265 { 266 return ns_capable(ns, CAP_CHECKPOINT_RESTORE) || 267 ns_capable(ns, CAP_SYS_ADMIN); 268 } 269 270 /* audit system wants to get cap info from files as well */ 271 extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps); 272 273 extern int cap_convert_nscap(struct dentry *dentry, const void **ivalue, size_t size); 274 275 #endif /* !_LINUX_CAPABILITY_H */ 276