1 /* 2 * linux/kernel/capability.c 3 * 4 * Copyright (C) 1997 Andrew Main <zefram@fysh.org> 5 * 6 * Integrated into 2.1.97+, Andrew G. Morgan <morgan@transmeta.com> 7 * 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net> 8 */ 9 10 #include <linux/capability.h> 11 #include <linux/mm.h> 12 #include <linux/module.h> 13 #include <linux/security.h> 14 #include <linux/syscalls.h> 15 #include <asm/uaccess.h> 16 17 unsigned securebits = SECUREBITS_DEFAULT; /* systemwide security settings */ 18 kernel_cap_t cap_bset = CAP_INIT_EFF_SET; 19 20 EXPORT_SYMBOL(securebits); 21 EXPORT_SYMBOL(cap_bset); 22 23 /* 24 * This lock protects task->cap_* for all tasks including current. 25 * Locking rule: acquire this prior to tasklist_lock. 26 */ 27 static DEFINE_SPINLOCK(task_capability_lock); 28 29 /* 30 * For sys_getproccap() and sys_setproccap(), any of the three 31 * capability set pointers may be NULL -- indicating that that set is 32 * uninteresting and/or not to be changed. 33 */ 34 35 /** 36 * sys_capget - get the capabilities of a given process. 37 * @header: pointer to struct that contains capability version and 38 * target pid data 39 * @dataptr: pointer to struct that contains the effective, permitted, 40 * and inheritable capabilities that are returned 41 * 42 * Returns 0 on success and < 0 on error. 43 */ 44 asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr) 45 { 46 int ret = 0; 47 pid_t pid; 48 __u32 version; 49 task_t *target; 50 struct __user_cap_data_struct data; 51 52 if (get_user(version, &header->version)) 53 return -EFAULT; 54 55 if (version != _LINUX_CAPABILITY_VERSION) { 56 if (put_user(_LINUX_CAPABILITY_VERSION, &header->version)) 57 return -EFAULT; 58 return -EINVAL; 59 } 60 61 if (get_user(pid, &header->pid)) 62 return -EFAULT; 63 64 if (pid < 0) 65 return -EINVAL; 66 67 spin_lock(&task_capability_lock); 68 read_lock(&tasklist_lock); 69 70 if (pid && pid != current->pid) { 71 target = find_task_by_pid(pid); 72 if (!target) { 73 ret = -ESRCH; 74 goto out; 75 } 76 } else 77 target = current; 78 79 ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted); 80 81 out: 82 read_unlock(&tasklist_lock); 83 spin_unlock(&task_capability_lock); 84 85 if (!ret && copy_to_user(dataptr, &data, sizeof data)) 86 return -EFAULT; 87 88 return ret; 89 } 90 91 /* 92 * cap_set_pg - set capabilities for all processes in a given process 93 * group. We call this holding task_capability_lock and tasklist_lock. 94 */ 95 static inline int cap_set_pg(int pgrp, kernel_cap_t *effective, 96 kernel_cap_t *inheritable, 97 kernel_cap_t *permitted) 98 { 99 task_t *g, *target; 100 int ret = -EPERM; 101 int found = 0; 102 103 do_each_task_pid(pgrp, PIDTYPE_PGID, g) { 104 target = g; 105 while_each_thread(g, target) { 106 if (!security_capset_check(target, effective, 107 inheritable, 108 permitted)) { 109 security_capset_set(target, effective, 110 inheritable, 111 permitted); 112 ret = 0; 113 } 114 found = 1; 115 } 116 } while_each_task_pid(pgrp, PIDTYPE_PGID, g); 117 118 if (!found) 119 ret = 0; 120 return ret; 121 } 122 123 /* 124 * cap_set_all - set capabilities for all processes other than init 125 * and self. We call this holding task_capability_lock and tasklist_lock. 126 */ 127 static inline int cap_set_all(kernel_cap_t *effective, 128 kernel_cap_t *inheritable, 129 kernel_cap_t *permitted) 130 { 131 task_t *g, *target; 132 int ret = -EPERM; 133 int found = 0; 134 135 do_each_thread(g, target) { 136 if (target == current || target->pid == 1) 137 continue; 138 found = 1; 139 if (security_capset_check(target, effective, inheritable, 140 permitted)) 141 continue; 142 ret = 0; 143 security_capset_set(target, effective, inheritable, permitted); 144 } while_each_thread(g, target); 145 146 if (!found) 147 ret = 0; 148 return ret; 149 } 150 151 /** 152 * sys_capset - set capabilities for a process or a group of processes 153 * @header: pointer to struct that contains capability version and 154 * target pid data 155 * @data: pointer to struct that contains the effective, permitted, 156 * and inheritable capabilities 157 * 158 * Set capabilities for a given process, all processes, or all 159 * processes in a given process group. 160 * 161 * The restrictions on setting capabilities are specified as: 162 * 163 * [pid is for the 'target' task. 'current' is the calling task.] 164 * 165 * I: any raised capabilities must be a subset of the (old current) permitted 166 * P: any raised capabilities must be a subset of the (old current) permitted 167 * E: must be set to a subset of (new target) permitted 168 * 169 * Returns 0 on success and < 0 on error. 170 */ 171 asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data) 172 { 173 kernel_cap_t inheritable, permitted, effective; 174 __u32 version; 175 task_t *target; 176 int ret; 177 pid_t pid; 178 179 if (get_user(version, &header->version)) 180 return -EFAULT; 181 182 if (version != _LINUX_CAPABILITY_VERSION) { 183 if (put_user(_LINUX_CAPABILITY_VERSION, &header->version)) 184 return -EFAULT; 185 return -EINVAL; 186 } 187 188 if (get_user(pid, &header->pid)) 189 return -EFAULT; 190 191 if (pid && pid != current->pid && !capable(CAP_SETPCAP)) 192 return -EPERM; 193 194 if (copy_from_user(&effective, &data->effective, sizeof(effective)) || 195 copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) || 196 copy_from_user(&permitted, &data->permitted, sizeof(permitted))) 197 return -EFAULT; 198 199 spin_lock(&task_capability_lock); 200 read_lock(&tasklist_lock); 201 202 if (pid > 0 && pid != current->pid) { 203 target = find_task_by_pid(pid); 204 if (!target) { 205 ret = -ESRCH; 206 goto out; 207 } 208 } else 209 target = current; 210 211 ret = 0; 212 213 /* having verified that the proposed changes are legal, 214 we now put them into effect. */ 215 if (pid < 0) { 216 if (pid == -1) /* all procs other than current and init */ 217 ret = cap_set_all(&effective, &inheritable, &permitted); 218 219 else /* all procs in process group */ 220 ret = cap_set_pg(-pid, &effective, &inheritable, 221 &permitted); 222 } else { 223 ret = security_capset_check(target, &effective, &inheritable, 224 &permitted); 225 if (!ret) 226 security_capset_set(target, &effective, &inheritable, 227 &permitted); 228 } 229 230 out: 231 read_unlock(&tasklist_lock); 232 spin_unlock(&task_capability_lock); 233 234 return ret; 235 } 236