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