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_EMPTY_SET ((kernel_cap_t){{ 0, 0 }}) 82 # define CAP_FULL_SET ((kernel_cap_t){{ ~0, ~0 }}) 83 # define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \ 84 | CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \ 85 CAP_FS_MASK_B1 } }) 86 # define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \ 87 | CAP_TO_MASK(CAP_SYS_RESOURCE), \ 88 CAP_FS_MASK_B1 } }) 89 90 #endif /* _KERNEL_CAPABILITY_U32S != 2 */ 91 92 # define cap_clear(c) do { (c) = __cap_empty_set; } while (0) 93 94 #define cap_raise(c, flag) ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag)) 95 #define cap_lower(c, flag) ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag)) 96 #define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag)) 97 98 #define CAP_BOP_ALL(c, a, b, OP) \ 99 do { \ 100 unsigned __capi; \ 101 CAP_FOR_EACH_U32(__capi) { \ 102 c.cap[__capi] = a.cap[__capi] OP b.cap[__capi]; \ 103 } \ 104 } while (0) 105 106 #define CAP_UOP_ALL(c, a, OP) \ 107 do { \ 108 unsigned __capi; \ 109 CAP_FOR_EACH_U32(__capi) { \ 110 c.cap[__capi] = OP a.cap[__capi]; \ 111 } \ 112 } while (0) 113 114 static inline kernel_cap_t cap_combine(const kernel_cap_t a, 115 const kernel_cap_t b) 116 { 117 kernel_cap_t dest; 118 CAP_BOP_ALL(dest, a, b, |); 119 return dest; 120 } 121 122 static inline kernel_cap_t cap_intersect(const kernel_cap_t a, 123 const kernel_cap_t b) 124 { 125 kernel_cap_t dest; 126 CAP_BOP_ALL(dest, a, b, &); 127 return dest; 128 } 129 130 static inline kernel_cap_t cap_drop(const kernel_cap_t a, 131 const kernel_cap_t drop) 132 { 133 kernel_cap_t dest; 134 CAP_BOP_ALL(dest, a, drop, &~); 135 return dest; 136 } 137 138 static inline kernel_cap_t cap_invert(const kernel_cap_t c) 139 { 140 kernel_cap_t dest; 141 CAP_UOP_ALL(dest, c, ~); 142 return dest; 143 } 144 145 static inline int cap_isclear(const kernel_cap_t a) 146 { 147 unsigned __capi; 148 CAP_FOR_EACH_U32(__capi) { 149 if (a.cap[__capi] != 0) 150 return 0; 151 } 152 return 1; 153 } 154 155 /* 156 * Check if "a" is a subset of "set". 157 * return 1 if ALL of the capabilities in "a" are also in "set" 158 * cap_issubset(0101, 1111) will return 1 159 * return 0 if ANY of the capabilities in "a" are not in "set" 160 * cap_issubset(1111, 0101) will return 0 161 */ 162 static inline int cap_issubset(const kernel_cap_t a, const kernel_cap_t set) 163 { 164 kernel_cap_t dest; 165 dest = cap_drop(a, set); 166 return cap_isclear(dest); 167 } 168 169 /* Used to decide between falling back on the old suser() or fsuser(). */ 170 171 static inline int cap_is_fs_cap(int cap) 172 { 173 const kernel_cap_t __cap_fs_set = CAP_FS_SET; 174 return !!(CAP_TO_MASK(cap) & __cap_fs_set.cap[CAP_TO_INDEX(cap)]); 175 } 176 177 static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a) 178 { 179 const kernel_cap_t __cap_fs_set = CAP_FS_SET; 180 return cap_drop(a, __cap_fs_set); 181 } 182 183 static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a, 184 const kernel_cap_t permitted) 185 { 186 const kernel_cap_t __cap_fs_set = CAP_FS_SET; 187 return cap_combine(a, 188 cap_intersect(permitted, __cap_fs_set)); 189 } 190 191 static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a) 192 { 193 const kernel_cap_t __cap_fs_set = CAP_NFSD_SET; 194 return cap_drop(a, __cap_fs_set); 195 } 196 197 static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a, 198 const kernel_cap_t permitted) 199 { 200 const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET; 201 return cap_combine(a, 202 cap_intersect(permitted, __cap_nfsd_set)); 203 } 204 205 extern bool has_capability(struct task_struct *t, int cap); 206 extern bool has_ns_capability(struct task_struct *t, 207 struct user_namespace *ns, int cap); 208 extern bool has_capability_noaudit(struct task_struct *t, int cap); 209 extern bool has_ns_capability_noaudit(struct task_struct *t, 210 struct user_namespace *ns, int cap); 211 extern bool capable(int cap); 212 extern bool ns_capable(struct user_namespace *ns, int cap); 213 extern bool inode_capable(const struct inode *inode, int cap); 214 extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap); 215 216 /* audit system wants to get cap info from files as well */ 217 extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps); 218 219 #endif /* !_LINUX_CAPABILITY_H */ 220