diff options
Diffstat (limited to 'kernel/capability.c')
| -rw-r--r-- | kernel/capability.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/kernel/capability.c b/kernel/capability.c new file mode 100644 index 00000000000..64db1ee820c --- /dev/null +++ b/kernel/capability.c @@ -0,0 +1,220 @@ +/* + * linux/kernel/capability.c + * + * Copyright (C) 1997 Andrew Main <zefram@fysh.org> + * + * Integrated into 2.1.97+, Andrew G. Morgan <morgan@transmeta.com> + * 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net> + */ + +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/security.h> +#include <linux/syscalls.h> +#include <asm/uaccess.h> + +unsigned securebits = SECUREBITS_DEFAULT; /* systemwide security settings */ +kernel_cap_t cap_bset = CAP_INIT_EFF_SET; + +EXPORT_SYMBOL(securebits); +EXPORT_SYMBOL(cap_bset); + +/* + * This lock protects task->cap_* for all tasks including current. + * Locking rule: acquire this prior to tasklist_lock. + */ +static DEFINE_SPINLOCK(task_capability_lock); + +/* + * For sys_getproccap() and sys_setproccap(), any of the three + * capability set pointers may be NULL -- indicating that that set is + * uninteresting and/or not to be changed. + */ + +/* + * sys_capget - get the capabilities of a given process. + */ +asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr) +{ + int ret = 0; + pid_t pid; + __u32 version; + task_t *target; + struct __user_cap_data_struct data; + + if (get_user(version, &header->version)) + return -EFAULT; + + if (version != _LINUX_CAPABILITY_VERSION) { + if (put_user(_LINUX_CAPABILITY_VERSION, &header->version)) + return -EFAULT; + return -EINVAL; + } + + if (get_user(pid, &header->pid)) + return -EFAULT; + + if (pid < 0) + return -EINVAL; + + spin_lock(&task_capability_lock); + read_lock(&tasklist_lock); + + if (pid && pid != current->pid) { + target = find_task_by_pid(pid); + if (!target) { + ret = -ESRCH; + goto out; + } + } else + target = current; + + ret = security_capget(target, &data.effective, &data.inheritable, &data.permitted); + +out: + read_unlock(&tasklist_lock); + spin_unlock(&task_capability_lock); + + if (!ret && copy_to_user(dataptr, &data, sizeof data)) + return -EFAULT; + + return ret; +} + +/* + * cap_set_pg - set capabilities for all processes in a given process + * group. We call this holding task_capability_lock and tasklist_lock. + */ +static inline int cap_set_pg(int pgrp, kernel_cap_t *effective, + kernel_cap_t *inheritable, + kernel_cap_t *permitted) +{ + task_t *g, *target; + int ret = -EPERM; + int found = 0; + + do_each_task_pid(pgrp, PIDTYPE_PGID, g) { + target = g; + while_each_thread(g, target) { + if (!security_capset_check(target, effective, + inheritable, + permitted)) { + security_capset_set(target, effective, + inheritable, + permitted); + ret = 0; + } + found = 1; + } + } while_each_task_pid(pgrp, PIDTYPE_PGID, g); + + if (!found) + ret = 0; + return ret; +} + +/* + * cap_set_all - set capabilities for all processes other than init + * and self. We call this holding task_capability_lock and tasklist_lock. + */ +static inline int cap_set_all(kernel_cap_t *effective, + kernel_cap_t *inheritable, + kernel_cap_t *permitted) +{ + task_t *g, *target; + int ret = -EPERM; + int found = 0; + + do_each_thread(g, target) { + if (target == current || target->pid == 1) + continue; + found = 1; + if (security_capset_check(target, effective, inheritable, + permitted)) + continue; + ret = 0; + security_capset_set(target, effective, inheritable, permitted); + } while_each_thread(g, target); + + if (!found) + ret = 0; + return ret; +} + +/* + * sys_capset - set capabilities for a given process, all processes, or all + * processes in a given process group. + * + * The restrictions on setting capabilities are specified as: + * + * [pid is for the 'target' task. 'current' is the calling task.] + * + * I: any raised capabilities must be a subset of the (old current) permitted + * P: any raised capabilities must be a subset of the (old current) permitted + * E: must be set to a subset of (new target) permitted + */ +asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data) +{ + kernel_cap_t inheritable, permitted, effective; + __u32 version; + task_t *target; + int ret; + pid_t pid; + + if (get_user(version, &header->version)) + return -EFAULT; + + if (version != _LINUX_CAPABILITY_VERSION) { + if (put_user(_LINUX_CAPABILITY_VERSION, &header->version)) + return -EFAULT; + return -EINVAL; + } + + if (get_user(pid, &header->pid)) + return -EFAULT; + + if (pid && pid != current->pid && !capable(CAP_SETPCAP)) + return -EPERM; + + if (copy_from_user(&effective, &data->effective, sizeof(effective)) || + copy_from_user(&inheritable, &data->inheritable, sizeof(inheritable)) || + copy_from_user(&permitted, &data->permitted, sizeof(permitted))) + return -EFAULT; + + spin_lock(&task_capability_lock); + read_lock(&tasklist_lock); + + if (pid > 0 && pid != current->pid) { + target = find_task_by_pid(pid); + if (!target) { + ret = -ESRCH; + goto out; + } + } else + target = current; + + ret = 0; + + /* having verified that the proposed changes are legal, + we now put them into effect. */ + if (pid < 0) { + if (pid == -1) /* all procs other than current and init */ + ret = cap_set_all(&effective, &inheritable, &permitted); + + else /* all procs in process group */ + ret = cap_set_pg(-pid, &effective, &inheritable, + &permitted); + } else { + ret = security_capset_check(target, &effective, &inheritable, + &permitted); + if (!ret) + security_capset_set(target, &effective, &inheritable, + &permitted); + } + +out: + read_unlock(&tasklist_lock); + spin_unlock(&task_capability_lock); + + return ret; +} |