* 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/syscalls.h>
#include <linux/pid_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);
+#include "cred-internals.h"
/*
* Leveraged for setting/resetting capabilities
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.
+ * Version 2 capabilities worked fine, but the linux/capability.h file
+ * that accompanied their introduction encouraged their use without
+ * the necessary user-space source code changes. As such, we have
+ * created a version 3 with equivalent functionality to version 2, but
+ * with a header change to protect legacy source code from using
+ * version 2 when it wanted to use version 1. If your system has code
+ * that trips the following warning, it is using version 2 specific
+ * capabilities and may be doing so insecurely.
+ *
+ * The remedy is to either upgrade your version of libcap (to 2.10+,
+ * if the application is linked against it), or recompile your
+ * application with modern kernel headers and this warning will go
+ * away.
*/
-/**
- * sys_capget - get the capabilities of a given process.
- * @header: pointer to struct that contains capability version and
- * target pid data
- * @dataptr: pointer to struct that contains the effective, permitted,
- * and inheritable capabilities that are returned
- *
- * Returns 0 on success and < 0 on error.
+static void warn_deprecated_v2(void)
+{
+ static int warned;
+
+ if (!warned) {
+ char name[sizeof(current->comm)];
+
+ printk(KERN_INFO "warning: `%s' uses deprecated v2"
+ " capabilities in a way that may be insecure.\n",
+ get_task_comm(name, current));
+ warned = 1;
+ }
+}
+
+/*
+ * Version check. Return the number of u32s in each capability flag
+ * array, or a negative value on error.
*/
-asmlinkage long sys_capget(cap_user_header_t header, cap_user_data_t dataptr)
+static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy)
{
- int ret = 0;
- pid_t pid;
__u32 version;
- struct task_struct *target;
- unsigned tocopy;
- kernel_cap_t pE, pI, pP;
if (get_user(version, &header->version))
return -EFAULT;
switch (version) {
case _LINUX_CAPABILITY_VERSION_1:
warn_legacy_capability_use();
- tocopy = _LINUX_CAPABILITY_U32S_1;
+ *tocopy = _LINUX_CAPABILITY_U32S_1;
break;
case _LINUX_CAPABILITY_VERSION_2:
- tocopy = _LINUX_CAPABILITY_U32S_2;
+ warn_deprecated_v2();
+ /*
+ * fall through - v3 is otherwise equivalent to v2.
+ */
+ case _LINUX_CAPABILITY_VERSION_3:
+ *tocopy = _LINUX_CAPABILITY_U32S_3;
break;
default:
- if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
+ if (put_user((u32)_KERNEL_CAPABILITY_VERSION, &header->version))
return -EFAULT;
return -EINVAL;
}
- if (get_user(pid, &header->pid))
- return -EFAULT;
+ return 0;
+}
- if (pid < 0)
- return -EINVAL;
+/*
+ * 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;
- spin_lock(&task_capability_lock);
- read_lock(&tasklist_lock);
+ read_lock(&tasklist_lock);
- if (pid && pid != task_pid_vnr(current)) {
target = find_task_by_vpid(pid);
- if (!target) {
+ if (!target)
ret = -ESRCH;
- goto out;
- }
+ else
+ ret = security_capget(target, pEp, pIp, pPp);
+
+ read_unlock(&tasklist_lock);
} else
- target = current;
+ ret = security_capget(current, pEp, pIp, pPp);
- ret = security_capget(target, &pE, &pI, &pP);
+ return ret;
+}
-out:
- read_unlock(&tasklist_lock);
- spin_unlock(&task_capability_lock);
+/**
+ * sys_capget - get the capabilities of a given process.
+ * @header: pointer to struct that contains capability version and
+ * target pid data
+ * @dataptr: pointer to struct that contains the effective, permitted,
+ * and inheritable capabilities that are returned
+ *
+ * Returns 0 on success and < 0 on error.
+ */
+SYSCALL_DEFINE2(capget, cap_user_header_t, header, cap_user_data_t, dataptr)
+{
+ int ret = 0;
+ pid_t pid;
+ unsigned tocopy;
+ kernel_cap_t pE, pI, pP;
+
+ ret = cap_validate_magic(header, &tocopy);
+ 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;
+
+ ret = cap_get_target_pid(pid, &pE, &pI, &pP);
if (!ret) {
- struct __user_cap_data_struct kdata[_LINUX_CAPABILITY_U32S];
+ struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
unsigned i;
for (i = 0; i < tocopy; i++) {
}
/*
- * Note, in the case, tocopy < _LINUX_CAPABILITY_U32S,
+ * Note, in the case, tocopy < _KERNEL_CAPABILITY_U32S,
* we silently drop the upper capabilities here. This
* has the effect of making older libcap
* implementations implicitly drop upper capability
* 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[_LINUX_CAPABILITY_U32S];
- unsigned i, tocopy;
+ struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
+ unsigned i, tocopy, copybytes;
kernel_cap_t inheritable, permitted, effective;
- __u32 version;
- struct task_struct *target;
+ struct cred *new;
int ret;
pid_t pid;
- if (get_user(version, &header->version))
- return -EFAULT;
-
- switch (version) {
- case _LINUX_CAPABILITY_VERSION_1:
- warn_legacy_capability_use();
- tocopy = _LINUX_CAPABILITY_U32S_1;
- break;
- case _LINUX_CAPABILITY_VERSION_2:
- tocopy = _LINUX_CAPABILITY_U32S_2;
- break;
- default:
- if (put_user(_LINUX_CAPABILITY_VERSION, &header->version))
- return -EFAULT;
- return -EINVAL;
- }
+ ret = cap_validate_magic(header, &tocopy);
+ if (ret != 0)
+ return ret;
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;
permitted.cap[i] = kdata[i].permitted;
inheritable.cap[i] = kdata[i].inheritable;
}
- while (i < _LINUX_CAPABILITY_U32S) {
+ while (i < _KERNEL_CAPABILITY_U32S) {
effective.cap[i] = 0;
permitted.cap[i] = 0;
inheritable.cap[i] = 0;
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)
+/**
+ * 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.
+ */
+int capable(int cap)
{
- if (security_capable(t, cap) == 0) {
- t->flags |= PF_SUPERPRIV;
+ if (unlikely(!cap_valid(cap))) {
+ printk(KERN_CRIT "capable() called with invalid cap=%u\n", cap);
+ BUG();
+ }
+
+ if (security_capable(cap) == 0) {
+ current->flags |= PF_SUPERPRIV;
return 1;
}
return 0;
}
-
-int capable(int cap)
-{
- return __capable(current, cap);
-}
EXPORT_SYMBOL(capable);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff