* 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net>
*/
+#include <linux/audit.h>
#include <linux/capability.h>
#include <linux/mm.h>
-#include <linux/module.h>
+#include <linux/export.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
#include <asm/uaccess.h>
-/*
- * This lock protects task->cap_* for all tasks including current.
- * Locking rule: acquire this prior to tasklist_lock.
- */
-static DEFINE_SPINLOCK(task_capability_lock);
-
/*
* Leveraged for setting/resetting capabilities
*/
const kernel_cap_t __cap_empty_set = CAP_EMPTY_SET;
-const kernel_cap_t __cap_full_set = CAP_FULL_SET;
-const kernel_cap_t __cap_init_eff_set = CAP_INIT_EFF_SET;
EXPORT_SYMBOL(__cap_empty_set);
-EXPORT_SYMBOL(__cap_full_set);
-EXPORT_SYMBOL(__cap_init_eff_set);
+
+int file_caps_enabled = 1;
+
+static int __init file_caps_disable(char *str)
+{
+ file_caps_enabled = 0;
+ return 1;
+}
+__setup("no_file_caps", file_caps_disable);
/*
* More recent versions of libcap are available from:
}
/*
- * 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.
+ * The only thing that can change the capabilities of the current
+ * process is the current process. As such, we can't be in this code
+ * at the same time as we are in the process of setting capabilities
+ * in this process. The net result is that we can limit our use of
+ * locks to when we are reading the caps of another process.
*/
+static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
+ kernel_cap_t *pIp, kernel_cap_t *pPp)
+{
+ int ret;
+
+ if (pid && (pid != task_pid_vnr(current))) {
+ struct task_struct *target;
+
+ rcu_read_lock();
+
+ target = find_task_by_vpid(pid);
+ if (!target)
+ ret = -ESRCH;
+ else
+ ret = security_capget(target, pEp, pIp, pPp);
+
+ rcu_read_unlock();
+ } else
+ ret = security_capget(current, pEp, pIp, pPp);
+
+ return ret;
+}
/**
* sys_capget - get the capabilities of a given process.
*
* Returns 0 on success and < 0 on error.
*/
-asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
+SYSCALL_DEFINE2(capget, cap_user_header_t, header, cap_user_data_t, dataptr)
{
int ret = 0;
pid_t pid;
- struct task_struct *target;
unsigned tocopy;
kernel_cap_t pE, pI, pP;
ret = cap_validate_magic(header, &tocopy);
- if (ret != 0)
- return ret;
+ if ((dataptr == NULL) || (ret != 0))
+ return ((dataptr == NULL) && (ret == -EINVAL)) ? 0 : ret;
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 != task_pid_vnr(current)) {
- target = find_task_by_vpid(pid);
- if (!target) {
- ret = -ESRCH;
- goto out;
- }
- } else
- target = current;
-
- ret = security_capget(target, &pE, &pI, &pP);
-
-out:
- read_unlock(&tasklist_lock);
- spin_unlock(&task_capability_lock);
-
+ ret = cap_get_target_pid(pid, &pE, &pI, &pP);
if (!ret) {
struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
unsigned i;
* before modification is attempted and the application
* fails.
*/
-
if (copy_to_user(dataptr, kdata, tocopy
* sizeof(struct __user_cap_data_struct))) {
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_nr, kernel_cap_t *effective,
- kernel_cap_t *inheritable,
- kernel_cap_t *permitted)
-{
- struct task_struct *g, *target;
- int ret = -EPERM;
- int found = 0;
- struct pid *pgrp;
-
- pgrp = find_vpid(pgrp_nr);
- do_each_pid_task(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_pid_task(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)
-{
- struct task_struct *g, *target;
- int ret = -EPERM;
- int found = 0;
-
- do_each_thread(g, target) {
- if (target == current || is_container_init(target->group_leader))
- 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 process or a group of processes
+ * sys_capset - set capabilities for a process or (*) a group of processes
* @header: pointer to struct that contains capability version and
* target pid data
* @data: pointer to struct that contains the effective, permitted,
* and inheritable capabilities
*
- * Set capabilities for a given process, all processes, or all
- * processes in a given process group.
+ * Set capabilities for the current process only. The ability to any other
+ * process(es) has been deprecated and removed.
*
* 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
+ * I: any raised capabilities must be a subset of the old permitted
+ * P: any raised capabilities must be a subset of the old permitted
+ * E: must be set to a subset of new permitted
*
* Returns 0 on success and < 0 on error.
*/
-asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
+SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data)
{
struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
- unsigned i, tocopy;
+ unsigned i, tocopy, copybytes;
kernel_cap_t inheritable, permitted, effective;
- struct task_struct *target;
+ struct cred *new;
int ret;
pid_t pid;
if (get_user(pid, &header->pid))
return -EFAULT;
- if (pid && pid != task_pid_vnr(current) && !capable(CAP_SETPCAP))
+ /* may only affect current now */
+ if (pid != 0 && pid != task_pid_vnr(current))
return -EPERM;
- if (copy_from_user(&kdata, data, tocopy
- * sizeof(struct __user_cap_data_struct))) {
+ copybytes = tocopy * sizeof(struct __user_cap_data_struct);
+ if (copybytes > sizeof(kdata))
+ return -EFAULT;
+
+ if (copy_from_user(&kdata, data, copybytes))
return -EFAULT;
- }
for (i = 0; i < tocopy; i++) {
effective.cap[i] = kdata[i].effective;
i++;
}
- spin_lock(&task_capability_lock);
- read_lock(&tasklist_lock);
+ new = prepare_creds();
+ if (!new)
+ return -ENOMEM;
- if (pid > 0 && pid != task_pid_vnr(current)) {
- target = find_task_by_vpid(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);
- }
+ ret = security_capset(new, current_cred(),
+ &effective, &inheritable, &permitted);
+ if (ret < 0)
+ goto error;
-out:
- read_unlock(&tasklist_lock);
- spin_unlock(&task_capability_lock);
+ audit_log_capset(pid, new, current_cred());
+ return commit_creds(new);
+
+error:
+ abort_creds(new);
return ret;
}
-int __capable(struct task_struct *t, int cap)
+/**
+ * has_ns_capability - Does a task have a capability in a specific user ns
+ * @t: The task in question
+ * @ns: target user namespace
+ * @cap: The capability to be tested for
+ *
+ * Return true if the specified task has the given superior capability
+ * currently in effect to the specified user namespace, false if not.
+ *
+ * Note that this does not set PF_SUPERPRIV on the task.
+ */
+bool has_ns_capability(struct task_struct *t,
+ struct user_namespace *ns, int cap)
+{
+ int ret;
+
+ rcu_read_lock();
+ ret = security_capable(__task_cred(t), ns, cap);
+ rcu_read_unlock();
+
+ return (ret == 0);
+}
+
+/**
+ * has_capability - Does a task have a capability in init_user_ns
+ * @t: The task in question
+ * @cap: The capability to be tested for
+ *
+ * Return true if the specified task has the given superior capability
+ * currently in effect to the initial user namespace, false if not.
+ *
+ * Note that this does not set PF_SUPERPRIV on the task.
+ */
+bool has_capability(struct task_struct *t, int cap)
+{
+ return has_ns_capability(t, &init_user_ns, cap);
+}
+
+/**
+ * has_ns_capability_noaudit - Does a task have a capability (unaudited)
+ * in a specific user ns.
+ * @t: The task in question
+ * @ns: target user namespace
+ * @cap: The capability to be tested for
+ *
+ * Return true if the specified task has the given superior capability
+ * currently in effect to the specified user namespace, false if not.
+ * Do not write an audit message for the check.
+ *
+ * Note that this does not set PF_SUPERPRIV on the task.
+ */
+bool has_ns_capability_noaudit(struct task_struct *t,
+ struct user_namespace *ns, int cap)
+{
+ int ret;
+
+ rcu_read_lock();
+ ret = security_capable_noaudit(__task_cred(t), ns, cap);
+ rcu_read_unlock();
+
+ return (ret == 0);
+}
+
+/**
+ * has_capability_noaudit - Does a task have a capability (unaudited) in the
+ * initial user ns
+ * @t: The task in question
+ * @cap: The capability to be tested for
+ *
+ * Return true if the specified task has the given superior capability
+ * currently in effect to init_user_ns, false if not. Don't write an
+ * audit message for the check.
+ *
+ * Note that this does not set PF_SUPERPRIV on the task.
+ */
+bool has_capability_noaudit(struct task_struct *t, int cap)
+{
+ return has_ns_capability_noaudit(t, &init_user_ns, cap);
+}
+
+/**
+ * ns_capable - Determine if the current task has a superior capability in effect
+ * @ns: The usernamespace we want the capability in
+ * @cap: The capability to be tested for
+ *
+ * Return true if the current task has the given superior capability currently
+ * available for use, false if not.
+ *
+ * This sets PF_SUPERPRIV on the task if the capability is available on the
+ * assumption that it's about to be used.
+ */
+bool ns_capable(struct user_namespace *ns, int cap)
{
- if (security_capable(t, cap) == 0) {
- t->flags |= PF_SUPERPRIV;
- return 1;
+ if (unlikely(!cap_valid(cap))) {
+ printk(KERN_CRIT "capable() called with invalid cap=%u\n", cap);
+ BUG();
}
- return 0;
+
+ if (security_capable(current_cred(), ns, cap) == 0) {
+ current->flags |= PF_SUPERPRIV;
+ return true;
+ }
+ return false;
}
+EXPORT_SYMBOL(ns_capable);
-int capable(int cap)
+/**
+ * capable - Determine if the current task has a superior capability in effect
+ * @cap: The capability to be tested for
+ *
+ * Return true if the current task has the given superior capability currently
+ * available for use, false if not.
+ *
+ * This sets PF_SUPERPRIV on the task if the capability is available on the
+ * assumption that it's about to be used.
+ */
+bool capable(int cap)
{
- return __capable(current, cap);
+ return ns_capable(&init_user_ns, cap);
}
EXPORT_SYMBOL(capable);
+
+/**
+ * nsown_capable - Check superior capability to one's own user_ns
+ * @cap: The capability in question
+ *
+ * Return true if the current task has the given superior capability
+ * targeted at its own user namespace.
+ */
+bool nsown_capable(int cap)
+{
+ return ns_capable(current_user_ns(), cap);
+}
Code Review / linux-2.6.git / blobdiff