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linux/kernel/sys.c
Linus Torvalds 4a87b197c1 Add additional LSM hooks for SafeSetID 
SafeSetID is capable of making allow/deny decisions for set*uid calls
 on a system, and we want to add similar functionality for set*gid
 calls. The work to do that is not yet complete, so probably won't make
 it in for v5.8, but we are looking to get this simple patch in for
 v5.8 since we have it ready. We are planning on the rest of the work
 for extending the SafeSetID LSM being merged during the v5.9 merge
 window.
 
 This patch was sent to the security mailing list and there were no objections.
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Merge tag 'LSM-add-setgid-hook-5.8-author-fix' of git://github.com/micah-morton/linux

Pull SafeSetID update from Micah Morton:
 "Add additional LSM hooks for SafeSetID

  SafeSetID is capable of making allow/deny decisions for set*uid calls
  on a system, and we want to add similar functionality for set*gid
  calls.

  The work to do that is not yet complete, so probably won't make it in
  for v5.8, but we are looking to get this simple patch in for v5.8
  since we have it ready.

  We are planning on the rest of the work for extending the SafeSetID
  LSM being merged during the v5.9 merge window"

* tag 'LSM-add-setgid-hook-5.8-author-fix' of git://github.com/micah-morton/linux:
  security: Add LSM hooks to set*gid syscalls
2020-06-14 11:39:31 -07:00

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// SPDX-License-Identifier: GPL-2.0
/*
* linux/kernel/sys.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/utsname.h>
#include <linux/mman.h>
#include <linux/reboot.h>
#include <linux/prctl.h>
#include <linux/highuid.h>
#include <linux/fs.h>
#include <linux/kmod.h>
#include <linux/perf_event.h>
#include <linux/resource.h>
#include <linux/kernel.h>
#include <linux/workqueue.h>
#include <linux/capability.h>
#include <linux/device.h>
#include <linux/key.h>
#include <linux/times.h>
#include <linux/posix-timers.h>
#include <linux/security.h>
#include <linux/dcookies.h>
#include <linux/suspend.h>
#include <linux/tty.h>
#include <linux/signal.h>
#include <linux/cn_proc.h>
#include <linux/getcpu.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/seccomp.h>
#include <linux/cpu.h>
#include <linux/personality.h>
#include <linux/ptrace.h>
#include <linux/fs_struct.h>
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/gfp.h>
#include <linux/syscore_ops.h>
#include <linux/version.h>
#include <linux/ctype.h>
#include <linux/compat.h>
#include <linux/syscalls.h>
#include <linux/kprobes.h>
#include <linux/user_namespace.h>
#include <linux/time_namespace.h>
#include <linux/binfmts.h>
#include <linux/sched.h>
#include <linux/sched/autogroup.h>
#include <linux/sched/loadavg.h>
#include <linux/sched/stat.h>
#include <linux/sched/mm.h>
#include <linux/sched/coredump.h>
#include <linux/sched/task.h>
#include <linux/sched/cputime.h>
#include <linux/rcupdate.h>
#include <linux/uidgid.h>
#include <linux/cred.h>
#include <linux/nospec.h>
#include <linux/kmsg_dump.h>
/* Move somewhere else to avoid recompiling? */
#include <generated/utsrelease.h>
#include <linux/uaccess.h>
#include <asm/io.h>
#include <asm/unistd.h>
#include "uid16.h"
#ifndef SET_UNALIGN_CTL
# define SET_UNALIGN_CTL(a, b) (-EINVAL)
#endif
#ifndef GET_UNALIGN_CTL
# define GET_UNALIGN_CTL(a, b) (-EINVAL)
#endif
#ifndef SET_FPEMU_CTL
# define SET_FPEMU_CTL(a, b) (-EINVAL)
#endif
#ifndef GET_FPEMU_CTL
# define GET_FPEMU_CTL(a, b) (-EINVAL)
#endif
#ifndef SET_FPEXC_CTL
# define SET_FPEXC_CTL(a, b) (-EINVAL)
#endif
#ifndef GET_FPEXC_CTL
# define GET_FPEXC_CTL(a, b) (-EINVAL)
#endif
#ifndef GET_ENDIAN
# define GET_ENDIAN(a, b) (-EINVAL)
#endif
#ifndef SET_ENDIAN
# define SET_ENDIAN(a, b) (-EINVAL)
#endif
#ifndef GET_TSC_CTL
# define GET_TSC_CTL(a) (-EINVAL)
#endif
#ifndef SET_TSC_CTL
# define SET_TSC_CTL(a) (-EINVAL)
#endif
#ifndef GET_FP_MODE
# define GET_FP_MODE(a) (-EINVAL)
#endif
#ifndef SET_FP_MODE
# define SET_FP_MODE(a,b) (-EINVAL)
#endif
#ifndef SVE_SET_VL
# define SVE_SET_VL(a) (-EINVAL)
#endif
#ifndef SVE_GET_VL
# define SVE_GET_VL() (-EINVAL)
#endif
#ifndef PAC_RESET_KEYS
# define PAC_RESET_KEYS(a, b) (-EINVAL)
#endif
#ifndef SET_TAGGED_ADDR_CTRL
# define SET_TAGGED_ADDR_CTRL(a) (-EINVAL)
#endif
#ifndef GET_TAGGED_ADDR_CTRL
# define GET_TAGGED_ADDR_CTRL() (-EINVAL)
#endif
/*
* this is where the system-wide overflow UID and GID are defined, for
* architectures that now have 32-bit UID/GID but didn't in the past
*/
int overflowuid = DEFAULT_OVERFLOWUID;
int overflowgid = DEFAULT_OVERFLOWGID;
EXPORT_SYMBOL(overflowuid);
EXPORT_SYMBOL(overflowgid);
/*
* the same as above, but for filesystems which can only store a 16-bit
* UID and GID. as such, this is needed on all architectures
*/
int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
int fs_overflowgid = DEFAULT_FS_OVERFLOWGID;
EXPORT_SYMBOL(fs_overflowuid);
EXPORT_SYMBOL(fs_overflowgid);
/*
* Returns true if current's euid is same as p's uid or euid,
* or has CAP_SYS_NICE to p's user_ns.
*
* Called with rcu_read_lock, creds are safe
*/
static bool set_one_prio_perm(struct task_struct *p)
{
const struct cred *cred = current_cred(), *pcred = __task_cred(p);
if (uid_eq(pcred->uid, cred->euid) ||
uid_eq(pcred->euid, cred->euid))
return true;
if (ns_capable(pcred->user_ns, CAP_SYS_NICE))
return true;
return false;
}
/*
* set the priority of a task
* - the caller must hold the RCU read lock
*/
static int set_one_prio(struct task_struct *p, int niceval, int error)
{
int no_nice;
if (!set_one_prio_perm(p)) {
error = -EPERM;
goto out;
}
if (niceval < task_nice(p) && !can_nice(p, niceval)) {
error = -EACCES;
goto out;
}
no_nice = security_task_setnice(p, niceval);
if (no_nice) {
error = no_nice;
goto out;
}
if (error == -ESRCH)
error = 0;
set_user_nice(p, niceval);
out:
return error;
}
SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
{
struct task_struct *g, *p;
struct user_struct *user;
const struct cred *cred = current_cred();
int error = -EINVAL;
struct pid *pgrp;
kuid_t uid;
if (which > PRIO_USER || which < PRIO_PROCESS)
goto out;
/* normalize: avoid signed division (rounding problems) */
error = -ESRCH;
if (niceval < MIN_NICE)
niceval = MIN_NICE;
if (niceval > MAX_NICE)
niceval = MAX_NICE;
rcu_read_lock();
read_lock(&tasklist_lock);
switch (which) {
case PRIO_PROCESS:
if (who)
p = find_task_by_vpid(who);
else
p = current;
if (p)
error = set_one_prio(p, niceval, error);
break;
case PRIO_PGRP:
if (who)
pgrp = find_vpid(who);
else
pgrp = task_pgrp(current);
do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
error = set_one_prio(p, niceval, error);
} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
break;
case PRIO_USER:
uid = make_kuid(cred->user_ns, who);
user = cred->user;
if (!who)
uid = cred->uid;
else if (!uid_eq(uid, cred->uid)) {
user = find_user(uid);
if (!user)
goto out_unlock; /* No processes for this user */
}
do_each_thread(g, p) {
if (uid_eq(task_uid(p), uid) && task_pid_vnr(p))
error = set_one_prio(p, niceval, error);
} while_each_thread(g, p);
if (!uid_eq(uid, cred->uid))
free_uid(user); /* For find_user() */
break;
}
out_unlock:
read_unlock(&tasklist_lock);
rcu_read_unlock();
out:
return error;
}
/*
* Ugh. To avoid negative return values, "getpriority()" will
* not return the normal nice-value, but a negated value that
* has been offset by 20 (ie it returns 40..1 instead of -20..19)
* to stay compatible.
*/
SYSCALL_DEFINE2(getpriority, int, which, int, who)
{
struct task_struct *g, *p;
struct user_struct *user;
const struct cred *cred = current_cred();
long niceval, retval = -ESRCH;
struct pid *pgrp;
kuid_t uid;
if (which > PRIO_USER || which < PRIO_PROCESS)
return -EINVAL;
rcu_read_lock();
read_lock(&tasklist_lock);
switch (which) {
case PRIO_PROCESS:
if (who)
p = find_task_by_vpid(who);
else
p = current;
if (p) {
niceval = nice_to_rlimit(task_nice(p));
if (niceval > retval)
retval = niceval;
}
break;
case PRIO_PGRP:
if (who)
pgrp = find_vpid(who);
else
pgrp = task_pgrp(current);
do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
niceval = nice_to_rlimit(task_nice(p));
if (niceval > retval)
retval = niceval;
} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
break;
case PRIO_USER:
uid = make_kuid(cred->user_ns, who);
user = cred->user;
if (!who)
uid = cred->uid;
else if (!uid_eq(uid, cred->uid)) {
user = find_user(uid);
if (!user)
goto out_unlock; /* No processes for this user */
}
do_each_thread(g, p) {
if (uid_eq(task_uid(p), uid) && task_pid_vnr(p)) {
niceval = nice_to_rlimit(task_nice(p));
if (niceval > retval)
retval = niceval;
}
} while_each_thread(g, p);
if (!uid_eq(uid, cred->uid))
free_uid(user); /* for find_user() */
break;
}
out_unlock:
read_unlock(&tasklist_lock);
rcu_read_unlock();
return retval;
}
/*
* Unprivileged users may change the real gid to the effective gid
* or vice versa. (BSD-style)
*
* If you set the real gid at all, or set the effective gid to a value not
* equal to the real gid, then the saved gid is set to the new effective gid.
*
* This makes it possible for a setgid program to completely drop its
* privileges, which is often a useful assertion to make when you are doing
* a security audit over a program.
*
* The general idea is that a program which uses just setregid() will be
* 100% compatible with BSD. A program which uses just setgid() will be
* 100% compatible with POSIX with saved IDs.
*
* SMP: There are not races, the GIDs are checked only by filesystem
* operations (as far as semantic preservation is concerned).
*/
#ifdef CONFIG_MULTIUSER
long __sys_setregid(gid_t rgid, gid_t egid)
{
struct user_namespace *ns = current_user_ns();
const struct cred *old;
struct cred *new;
int retval;
kgid_t krgid, kegid;
krgid = make_kgid(ns, rgid);
kegid = make_kgid(ns, egid);
if ((rgid != (gid_t) -1) && !gid_valid(krgid))
return -EINVAL;
if ((egid != (gid_t) -1) && !gid_valid(kegid))
return -EINVAL;
new = prepare_creds();
if (!new)
return -ENOMEM;
old = current_cred();
retval = -EPERM;
if (rgid != (gid_t) -1) {
if (gid_eq(old->gid, krgid) ||
gid_eq(old->egid, krgid) ||
ns_capable(old->user_ns, CAP_SETGID))
new->gid = krgid;
else
goto error;
}
if (egid != (gid_t) -1) {
if (gid_eq(old->gid, kegid) ||
gid_eq(old->egid, kegid) ||
gid_eq(old->sgid, kegid) ||
ns_capable(old->user_ns, CAP_SETGID))
new->egid = kegid;
else
goto error;
}
if (rgid != (gid_t) -1 ||
(egid != (gid_t) -1 && !gid_eq(kegid, old->gid)))
new->sgid = new->egid;
new->fsgid = new->egid;
retval = security_task_fix_setgid(new, old, LSM_SETID_RE);
if (retval < 0)
goto error;
return commit_creds(new);
error:
abort_creds(new);
return retval;
}
SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
{
return __sys_setregid(rgid, egid);
}
/*
* setgid() is implemented like SysV w/ SAVED_IDS
*
* SMP: Same implicit races as above.
*/
long __sys_setgid(gid_t gid)
{
struct user_namespace *ns = current_user_ns();
const struct cred *old;
struct cred *new;
int retval;
kgid_t kgid;
kgid = make_kgid(ns, gid);
if (!gid_valid(kgid))
return -EINVAL;
new = prepare_creds();
if (!new)
return -ENOMEM;
old = current_cred();
retval = -EPERM;
if (ns_capable(old->user_ns, CAP_SETGID))
new->gid = new->egid = new->sgid = new->fsgid = kgid;
else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
new->egid = new->fsgid = kgid;
else
goto error;
retval = security_task_fix_setgid(new, old, LSM_SETID_ID);
if (retval < 0)
goto error;
return commit_creds(new);
error:
abort_creds(new);
return retval;
}
SYSCALL_DEFINE1(setgid, gid_t, gid)
{
return __sys_setgid(gid);
}
/*
* change the user struct in a credentials set to match the new UID
*/
static int set_user(struct cred *new)
{
struct user_struct *new_user;
new_user = alloc_uid(new->uid);
if (!new_user)
return -EAGAIN;
/*
* We don't fail in case of NPROC limit excess here because too many
* poorly written programs don't check set*uid() return code, assuming
* it never fails if called by root. We may still enforce NPROC limit
* for programs doing set*uid()+execve() by harmlessly deferring the
* failure to the execve() stage.
*/
if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
new_user != INIT_USER)
current->flags |= PF_NPROC_EXCEEDED;
else
current->flags &= ~PF_NPROC_EXCEEDED;
free_uid(new->user);
new->user = new_user;
return 0;
}
/*
* Unprivileged users may change the real uid to the effective uid
* or vice versa. (BSD-style)
*
* If you set the real uid at all, or set the effective uid to a value not
* equal to the real uid, then the saved uid is set to the new effective uid.
*
* This makes it possible for a setuid program to completely drop its
* privileges, which is often a useful assertion to make when you are doing
* a security audit over a program.
*
* The general idea is that a program which uses just setreuid() will be
* 100% compatible with BSD. A program which uses just setuid() will be
* 100% compatible with POSIX with saved IDs.
*/
long __sys_setreuid(uid_t ruid, uid_t euid)
{
struct user_namespace *ns = current_user_ns();
const struct cred *old;
struct cred *new;
int retval;
kuid_t kruid, keuid;
kruid = make_kuid(ns, ruid);
keuid = make_kuid(ns, euid);
if ((ruid != (uid_t) -1) && !uid_valid(kruid))
return -EINVAL;
if ((euid != (uid_t) -1) && !uid_valid(keuid))
return -EINVAL;
new = prepare_creds();
if (!new)
return -ENOMEM;
old = current_cred();
retval = -EPERM;
if (ruid != (uid_t) -1) {
new->uid = kruid;
if (!uid_eq(old->uid, kruid) &&
!uid_eq(old->euid, kruid) &&
!ns_capable_setid(old->user_ns, CAP_SETUID))
goto error;
}
if (euid != (uid_t) -1) {
new->euid = keuid;
if (!uid_eq(old->uid, keuid) &&
!uid_eq(old->euid, keuid) &&
!uid_eq(old->suid, keuid) &&
!ns_capable_setid(old->user_ns, CAP_SETUID))
goto error;
}
if (!uid_eq(new->uid, old->uid)) {
retval = set_user(new);
if (retval < 0)
goto error;
}
if (ruid != (uid_t) -1 ||
(euid != (uid_t) -1 && !uid_eq(keuid, old->uid)))
new->suid = new->euid;
new->fsuid = new->euid;
retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
if (retval < 0)
goto error;
return commit_creds(new);
error:
abort_creds(new);
return retval;
}
SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
{
return __sys_setreuid(ruid, euid);
}
/*
* setuid() is implemented like SysV with SAVED_IDS
*
* Note that SAVED_ID's is deficient in that a setuid root program
* like sendmail, for example, cannot set its uid to be a normal
* user and then switch back, because if you're root, setuid() sets
* the saved uid too. If you don't like this, blame the bright people
* in the POSIX committee and/or USG. Note that the BSD-style setreuid()
* will allow a root program to temporarily drop privileges and be able to
* regain them by swapping the real and effective uid.
*/
long __sys_setuid(uid_t uid)
{
struct user_namespace *ns = current_user_ns();
const struct cred *old;
struct cred *new;
int retval;
kuid_t kuid;
kuid = make_kuid(ns, uid);
if (!uid_valid(kuid))
return -EINVAL;
new = prepare_creds();
if (!new)
return -ENOMEM;
old = current_cred();
retval = -EPERM;
if (ns_capable_setid(old->user_ns, CAP_SETUID)) {
new->suid = new->uid = kuid;
if (!uid_eq(kuid, old->uid)) {
retval = set_user(new);
if (retval < 0)
goto error;
}
} else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) {
goto error;
}
new->fsuid = new->euid = kuid;
retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
if (retval < 0)
goto error;
return commit_creds(new);
error:
abort_creds(new);
return retval;
}
SYSCALL_DEFINE1(setuid, uid_t, uid)
{
return __sys_setuid(uid);
}
/*
* This function implements a generic ability to update ruid, euid,
* and suid. This allows you to implement the 4.4 compatible seteuid().
*/
long __sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
{
struct user_namespace *ns = current_user_ns();
const struct cred *old;
struct cred *new;
int retval;
kuid_t kruid, keuid, ksuid;
kruid = make_kuid(ns, ruid);
keuid = make_kuid(ns, euid);
ksuid = make_kuid(ns, suid);
if ((ruid != (uid_t) -1) && !uid_valid(kruid))
return -EINVAL;
if ((euid != (uid_t) -1) && !uid_valid(keuid))
return -EINVAL;
if ((suid != (uid_t) -1) && !uid_valid(ksuid))
return -EINVAL;
new = prepare_creds();
if (!new)
return -ENOMEM;
old = current_cred();
retval = -EPERM;
if (!ns_capable_setid(old->user_ns, CAP_SETUID)) {
if (ruid != (uid_t) -1 && !uid_eq(kruid, old->uid) &&
!uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid))
goto error;
if (euid != (uid_t) -1 && !uid_eq(keuid, old->uid) &&
!uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid))
goto error;
if (suid != (uid_t) -1 && !uid_eq(ksuid, old->uid) &&
!uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid))
goto error;
}
if (ruid != (uid_t) -1) {
new->uid = kruid;
if (!uid_eq(kruid, old->uid)) {
retval = set_user(new);
if (retval < 0)
goto error;
}
}
if (euid != (uid_t) -1)
new->euid = keuid;
if (suid != (uid_t) -1)
new->suid = ksuid;
new->fsuid = new->euid;
retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
if (retval < 0)
goto error;
return commit_creds(new);
error:
abort_creds(new);
return retval;
}
SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
{
return __sys_setresuid(ruid, euid, suid);
}
SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp)
{
const struct cred *cred = current_cred();
int retval;
uid_t ruid, euid, suid;
ruid = from_kuid_munged(cred->user_ns, cred->uid);
euid = from_kuid_munged(cred->user_ns, cred->euid);
suid = from_kuid_munged(cred->user_ns, cred->suid);
retval = put_user(ruid, ruidp);
if (!retval) {
retval = put_user(euid, euidp);
if (!retval)
return put_user(suid, suidp);
}
return retval;
}
/*
* Same as above, but for rgid, egid, sgid.
*/
long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
{
struct user_namespace *ns = current_user_ns();
const struct cred *old;
struct cred *new;
int retval;
kgid_t krgid, kegid, ksgid;
krgid = make_kgid(ns, rgid);
kegid = make_kgid(ns, egid);
ksgid = make_kgid(ns, sgid);
if ((rgid != (gid_t) -1) && !gid_valid(krgid))
return -EINVAL;
if ((egid != (gid_t) -1) && !gid_valid(kegid))
return -EINVAL;
if ((sgid != (gid_t) -1) && !gid_valid(ksgid))
return -EINVAL;
new = prepare_creds();
if (!new)
return -ENOMEM;
old = current_cred();
retval = -EPERM;
if (!ns_capable(old->user_ns, CAP_SETGID)) {
if (rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) &&
!gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
goto error;
if (egid != (gid_t) -1 && !gid_eq(kegid, old->gid) &&
!gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid))
goto error;
if (sgid != (gid_t) -1 && !gid_eq(ksgid, old->gid) &&
!gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid))
goto error;
}
if (rgid != (gid_t) -1)
new->gid = krgid;
if (egid != (gid_t) -1)
new->egid = kegid;
if (sgid != (gid_t) -1)
new->sgid = ksgid;
new->fsgid = new->egid;
retval = security_task_fix_setgid(new, old, LSM_SETID_RES);
if (retval < 0)
goto error;
return commit_creds(new);
error:
abort_creds(new);
return retval;
}
SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
{
return __sys_setresgid(rgid, egid, sgid);
}
SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp)
{
const struct cred *cred = current_cred();
int retval;
gid_t rgid, egid, sgid;
rgid = from_kgid_munged(cred->user_ns, cred->gid);
egid = from_kgid_munged(cred->user_ns, cred->egid);
sgid = from_kgid_munged(cred->user_ns, cred->sgid);
retval = put_user(rgid, rgidp);
if (!retval) {
retval = put_user(egid, egidp);
if (!retval)
retval = put_user(sgid, sgidp);
}
return retval;
}
/*
* "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
* is used for "access()" and for the NFS daemon (letting nfsd stay at
* whatever uid it wants to). It normally shadows "euid", except when
* explicitly set by setfsuid() or for access..
*/
long __sys_setfsuid(uid_t uid)
{
const struct cred *old;
struct cred *new;
uid_t old_fsuid;
kuid_t kuid;
old = current_cred();
old_fsuid = from_kuid_munged(old->user_ns, old->fsuid);
kuid = make_kuid(old->user_ns, uid);
if (!uid_valid(kuid))
return old_fsuid;
new = prepare_creds();
if (!new)
return old_fsuid;
if (uid_eq(kuid, old->uid) || uid_eq(kuid, old->euid) ||
uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) ||
ns_capable_setid(old->user_ns, CAP_SETUID)) {
if (!uid_eq(kuid, old->fsuid)) {
new->fsuid = kuid;
if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
goto change_okay;
}
}
abort_creds(new);
return old_fsuid;
change_okay:
commit_creds(new);
return old_fsuid;
}
SYSCALL_DEFINE1(setfsuid, uid_t, uid)
{
return __sys_setfsuid(uid);
}
/*
* Samma på svenska..
*/
long __sys_setfsgid(gid_t gid)
{
const struct cred *old;
struct cred *new;
gid_t old_fsgid;
kgid_t kgid;
old = current_cred();
old_fsgid = from_kgid_munged(old->user_ns, old->fsgid);
kgid = make_kgid(old->user_ns, gid);
if (!gid_valid(kgid))
return old_fsgid;
new = prepare_creds();
if (!new)
return old_fsgid;
if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->egid) ||
gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
ns_capable(old->user_ns, CAP_SETGID)) {
if (!gid_eq(kgid, old->fsgid)) {
new->fsgid = kgid;
if (security_task_fix_setgid(new,old,LSM_SETID_FS) == 0)
goto change_okay;
}
}
abort_creds(new);
return old_fsgid;
change_okay:
commit_creds(new);
return old_fsgid;
}
SYSCALL_DEFINE1(setfsgid, gid_t, gid)
{
return __sys_setfsgid(gid);
}
#endif /* CONFIG_MULTIUSER */
/**
* sys_getpid - return the thread group id of the current process
*
* Note, despite the name, this returns the tgid not the pid. The tgid and
* the pid are identical unless CLONE_THREAD was specified on clone() in
* which case the tgid is the same in all threads of the same group.
*
* This is SMP safe as current->tgid does not change.
*/
SYSCALL_DEFINE0(getpid)
{
return task_tgid_vnr(current);
}
/* Thread ID - the internal kernel "pid" */
SYSCALL_DEFINE0(gettid)
{
return task_pid_vnr(current);
}
/*
* Accessing ->real_parent is not SMP-safe, it could
* change from under us. However, we can use a stale
* value of ->real_parent under rcu_read_lock(), see
* release_task()->call_rcu(delayed_put_task_struct).
*/
SYSCALL_DEFINE0(getppid)
{
int pid;
rcu_read_lock();
pid = task_tgid_vnr(rcu_dereference(current->real_parent));
rcu_read_unlock();
return pid;
}
SYSCALL_DEFINE0(getuid)
{
/* Only we change this so SMP safe */
return from_kuid_munged(current_user_ns(), current_uid());
}
SYSCALL_DEFINE0(geteuid)
{
/* Only we change this so SMP safe */
return from_kuid_munged(current_user_ns(), current_euid());
}
SYSCALL_DEFINE0(getgid)
{
/* Only we change this so SMP safe */
return from_kgid_munged(current_user_ns(), current_gid());
}
SYSCALL_DEFINE0(getegid)
{
/* Only we change this so SMP safe */
return from_kgid_munged(current_user_ns(), current_egid());
}
static void do_sys_times(struct tms *tms)
{
u64 tgutime, tgstime, cutime, cstime;
thread_group_cputime_adjusted(current, &tgutime, &tgstime);
cutime = current->signal->cutime;
cstime = current->signal->cstime;
tms->tms_utime = nsec_to_clock_t(tgutime);
tms->tms_stime = nsec_to_clock_t(tgstime);
tms->tms_cutime = nsec_to_clock_t(cutime);
tms->tms_cstime = nsec_to_clock_t(cstime);
}
SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
{
if (tbuf) {
struct tms tmp;
do_sys_times(&tmp);
if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
return -EFAULT;
}
force_successful_syscall_return();
return (long) jiffies_64_to_clock_t(get_jiffies_64());
}
#ifdef CONFIG_COMPAT
static compat_clock_t clock_t_to_compat_clock_t(clock_t x)
{
return compat_jiffies_to_clock_t(clock_t_to_jiffies(x));
}
COMPAT_SYSCALL_DEFINE1(times, struct compat_tms __user *, tbuf)
{
if (tbuf) {
struct tms tms;
struct compat_tms tmp;
do_sys_times(&tms);
/* Convert our struct tms to the compat version. */
tmp.tms_utime = clock_t_to_compat_clock_t(tms.tms_utime);
tmp.tms_stime = clock_t_to_compat_clock_t(tms.tms_stime);
tmp.tms_cutime = clock_t_to_compat_clock_t(tms.tms_cutime);
tmp.tms_cstime = clock_t_to_compat_clock_t(tms.tms_cstime);
if (copy_to_user(tbuf, &tmp, sizeof(tmp)))
return -EFAULT;
}
force_successful_syscall_return();
return compat_jiffies_to_clock_t(jiffies);
}
#endif
/*
* This needs some heavy checking ...
* I just haven't the stomach for it. I also don't fully
* understand sessions/pgrp etc. Let somebody who does explain it.
*
* OK, I think I have the protection semantics right.... this is really
* only important on a multi-user system anyway, to make sure one user
* can't send a signal to a process owned by another. -TYT, 12/12/91
*
* !PF_FORKNOEXEC check to conform completely to POSIX.
*/
SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
{
struct task_struct *p;
struct task_struct *group_leader = current->group_leader;
struct pid *pgrp;
int err;
if (!pid)
pid = task_pid_vnr(group_leader);
if (!pgid)
pgid = pid;
if (pgid < 0)
return -EINVAL;
rcu_read_lock();
/* From this point forward we keep holding onto the tasklist lock
* so that our parent does not change from under us. -DaveM
*/
write_lock_irq(&tasklist_lock);
err = -ESRCH;
p = find_task_by_vpid(pid);
if (!p)
goto out;
err = -EINVAL;
if (!thread_group_leader(p))
goto out;
if (same_thread_group(p->real_parent, group_leader)) {
err = -EPERM;
if (task_session(p) != task_session(group_leader))
goto out;
err = -EACCES;
if (!(p->flags & PF_FORKNOEXEC))
goto out;
} else {
err = -ESRCH;
if (p != group_leader)
goto out;
}
err = -EPERM;
if (p->signal->leader)
goto out;
pgrp = task_pid(p);
if (pgid != pid) {
struct task_struct *g;
pgrp = find_vpid(pgid);
g = pid_task(pgrp, PIDTYPE_PGID);
if (!g || task_session(g) != task_session(group_leader))
goto out;
}
err = security_task_setpgid(p, pgid);
if (err)
goto out;
if (task_pgrp(p) != pgrp)
change_pid(p, PIDTYPE_PGID, pgrp);
err = 0;
out:
/* All paths lead to here, thus we are safe. -DaveM */
write_unlock_irq(&tasklist_lock);
rcu_read_unlock();
return err;
}
static int do_getpgid(pid_t pid)
{
struct task_struct *p;
struct pid *grp;
int retval;
rcu_read_lock();
if (!pid)
grp = task_pgrp(current);
else {
retval = -ESRCH;
p = find_task_by_vpid(pid);
if (!p)
goto out;
grp = task_pgrp(p);
if (!grp)
goto out;
retval = security_task_getpgid(p);
if (retval)
goto out;
}
retval = pid_vnr(grp);
out:
rcu_read_unlock();
return retval;
}
SYSCALL_DEFINE1(getpgid, pid_t, pid)
{
return do_getpgid(pid);
}
#ifdef __ARCH_WANT_SYS_GETPGRP
SYSCALL_DEFINE0(getpgrp)
{
return do_getpgid(0);
}
#endif
SYSCALL_DEFINE1(getsid, pid_t, pid)
{
struct task_struct *p;
struct pid *sid;
int retval;
rcu_read_lock();
if (!pid)
sid = task_session(current);
else {
retval = -ESRCH;
p = find_task_by_vpid(pid);
if (!p)
goto out;
sid = task_session(p);
if (!sid)
goto out;
retval = security_task_getsid(p);
if (retval)
goto out;
}
retval = pid_vnr(sid);
out:
rcu_read_unlock();
return retval;
}
static void set_special_pids(struct pid *pid)
{
struct task_struct *curr = current->group_leader;
if (task_session(curr) != pid)
change_pid(curr, PIDTYPE_SID, pid);
if (task_pgrp(curr) != pid)
change_pid(curr, PIDTYPE_PGID, pid);
}
int ksys_setsid(void)
{
struct task_struct *group_leader = current->group_leader;
struct pid *sid = task_pid(group_leader);
pid_t session = pid_vnr(sid);
int err = -EPERM;
write_lock_irq(&tasklist_lock);
/* Fail if I am already a session leader */
if (group_leader->signal->leader)
goto out;
/* Fail if a process group id already exists that equals the
* proposed session id.
*/
if (pid_task(sid, PIDTYPE_PGID))
goto out;
group_leader->signal->leader = 1;
set_special_pids(sid);
proc_clear_tty(group_leader);
err = session;
out:
write_unlock_irq(&tasklist_lock);
if (err > 0) {
proc_sid_connector(group_leader);
sched_autogroup_create_attach(group_leader);
}
return err;
}
SYSCALL_DEFINE0(setsid)
{
return ksys_setsid();
}
DECLARE_RWSEM(uts_sem);
#ifdef COMPAT_UTS_MACHINE
#define override_architecture(name) \
(personality(current->personality) == PER_LINUX32 && \
copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
sizeof(COMPAT_UTS_MACHINE)))
#else
#define override_architecture(name) 0
#endif
/*
* Work around broken programs that cannot handle "Linux 3.0".
* Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
* And we map 4.x and later versions to 2.6.60+x, so 4.0/5.0/6.0/... would be
* 2.6.60.
*/
static int override_release(char __user *release, size_t len)
{
int ret = 0;
if (current->personality & UNAME26) {
const char *rest = UTS_RELEASE;
char buf[65] = { 0 };
int ndots = 0;
unsigned v;
size_t copy;
while (*rest) {
if (*rest == '.' && ++ndots >= 3)
break;
if (!isdigit(*rest) && *rest != '.')
break;
rest++;
}
v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 60;
copy = clamp_t(size_t, len, 1, sizeof(buf));
copy = scnprintf(buf, copy, "2.6.%u%s", v, rest);
ret = copy_to_user(release, buf, copy + 1);
}
return ret;
}
SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
{
struct new_utsname tmp;
down_read(&uts_sem);
memcpy(&tmp, utsname(), sizeof(tmp));
up_read(&uts_sem);
if (copy_to_user(name, &tmp, sizeof(tmp)))
return -EFAULT;
if (override_release(name->release, sizeof(name->release)))
return -EFAULT;
if (override_architecture(name))
return -EFAULT;
return 0;
}
#ifdef __ARCH_WANT_SYS_OLD_UNAME
/*
* Old cruft
*/
SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
{
struct old_utsname tmp;
if (!name)
return -EFAULT;
down_read(&uts_sem);
memcpy(&tmp, utsname(), sizeof(tmp));
up_read(&uts_sem);
if (copy_to_user(name, &tmp, sizeof(tmp)))
return -EFAULT;
if (override_release(name->release, sizeof(name->release)))
return -EFAULT;
if (override_architecture(name))
return -EFAULT;
return 0;
}
SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
{
struct oldold_utsname tmp;
if (!name)
return -EFAULT;
memset(&tmp, 0, sizeof(tmp));
down_read(&uts_sem);
memcpy(&tmp.sysname, &utsname()->sysname, __OLD_UTS_LEN);
memcpy(&tmp.nodename, &utsname()->nodename, __OLD_UTS_LEN);
memcpy(&tmp.release, &utsname()->release, __OLD_UTS_LEN);
memcpy(&tmp.version, &utsname()->version, __OLD_UTS_LEN);
memcpy(&tmp.machine, &utsname()->machine, __OLD_UTS_LEN);
up_read(&uts_sem);
if (copy_to_user(name, &tmp, sizeof(tmp)))
return -EFAULT;
if (override_architecture(name))
return -EFAULT;
if (override_release(name->release, sizeof(name->release)))
return -EFAULT;
return 0;
}
#endif
SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
{
int errno;
char tmp[__NEW_UTS_LEN];
if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
if (len < 0 || len > __NEW_UTS_LEN)
return -EINVAL;
errno = -EFAULT;
if (!copy_from_user(tmp, name, len)) {
struct new_utsname *u;
down_write(&uts_sem);
u = utsname();
memcpy(u->nodename, tmp, len);
memset(u->nodename + len, 0, sizeof(u->nodename) - len);
errno = 0;
uts_proc_notify(UTS_PROC_HOSTNAME);
up_write(&uts_sem);
}
return errno;
}
#ifdef __ARCH_WANT_SYS_GETHOSTNAME
SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
{
int i;
struct new_utsname *u;
char tmp[__NEW_UTS_LEN + 1];
if (len < 0)
return -EINVAL;
down_read(&uts_sem);
u = utsname();
i = 1 + strlen(u->nodename);
if (i > len)
i = len;
memcpy(tmp, u->nodename, i);
up_read(&uts_sem);
if (copy_to_user(name, tmp, i))
return -EFAULT;
return 0;
}
#endif
/*
* Only setdomainname; getdomainname can be implemented by calling
* uname()
*/
SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
{
int errno;
char tmp[__NEW_UTS_LEN];
if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
if (len < 0 || len > __NEW_UTS_LEN)
return -EINVAL;
errno = -EFAULT;
if (!copy_from_user(tmp, name, len)) {
struct new_utsname *u;
down_write(&uts_sem);
u = utsname();
memcpy(u->domainname, tmp, len);
memset(u->domainname + len, 0, sizeof(u->domainname) - len);
errno = 0;
uts_proc_notify(UTS_PROC_DOMAINNAME);
up_write(&uts_sem);
}
return errno;
}
SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
{
struct rlimit value;
int ret;
ret = do_prlimit(current, resource, NULL, &value);
if (!ret)
ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
return ret;
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE2(setrlimit, unsigned int, resource,
struct compat_rlimit __user *, rlim)
{
struct rlimit r;
struct compat_rlimit r32;
if (copy_from_user(&r32, rlim, sizeof(struct compat_rlimit)))
return -EFAULT;
if (r32.rlim_cur == COMPAT_RLIM_INFINITY)
r.rlim_cur = RLIM_INFINITY;
else
r.rlim_cur = r32.rlim_cur;
if (r32.rlim_max == COMPAT_RLIM_INFINITY)
r.rlim_max = RLIM_INFINITY;
else
r.rlim_max = r32.rlim_max;
return do_prlimit(current, resource, &r, NULL);
}
COMPAT_SYSCALL_DEFINE2(getrlimit, unsigned int, resource,
struct compat_rlimit __user *, rlim)
{
struct rlimit r;
int ret;
ret = do_prlimit(current, resource, NULL, &r);
if (!ret) {
struct compat_rlimit r32;
if (r.rlim_cur > COMPAT_RLIM_INFINITY)
r32.rlim_cur = COMPAT_RLIM_INFINITY;
else
r32.rlim_cur = r.rlim_cur;
if (r.rlim_max > COMPAT_RLIM_INFINITY)
r32.rlim_max = COMPAT_RLIM_INFINITY;
else
r32.rlim_max = r.rlim_max;
if (copy_to_user(rlim, &r32, sizeof(struct compat_rlimit)))
return -EFAULT;
}
return ret;
}
#endif
#ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
/*
* Back compatibility for getrlimit. Needed for some apps.
*/
SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
struct rlimit __user *, rlim)
{
struct rlimit x;
if (resource >= RLIM_NLIMITS)
return -EINVAL;
resource = array_index_nospec(resource, RLIM_NLIMITS);
task_lock(current->group_leader);
x = current->signal->rlim[resource];
task_unlock(current->group_leader);
if (x.rlim_cur > 0x7FFFFFFF)
x.rlim_cur = 0x7FFFFFFF;
if (x.rlim_max > 0x7FFFFFFF)
x.rlim_max = 0x7FFFFFFF;
return copy_to_user(rlim, &x, sizeof(x)) ? -EFAULT : 0;
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
struct compat_rlimit __user *, rlim)
{
struct rlimit r;
if (resource >= RLIM_NLIMITS)
return -EINVAL;
resource = array_index_nospec(resource, RLIM_NLIMITS);
task_lock(current->group_leader);
r = current->signal->rlim[resource];
task_unlock(current->group_leader);
if (r.rlim_cur > 0x7FFFFFFF)
r.rlim_cur = 0x7FFFFFFF;
if (r.rlim_max > 0x7FFFFFFF)
r.rlim_max = 0x7FFFFFFF;
if (put_user(r.rlim_cur, &rlim->rlim_cur) ||
put_user(r.rlim_max, &rlim->rlim_max))
return -EFAULT;
return 0;
}
#endif
#endif
static inline bool rlim64_is_infinity(__u64 rlim64)
{
#if BITS_PER_LONG < 64
return rlim64 >= ULONG_MAX;
#else
return rlim64 == RLIM64_INFINITY;
#endif
}
static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
{
if (rlim->rlim_cur == RLIM_INFINITY)
rlim64->rlim_cur = RLIM64_INFINITY;
else
rlim64->rlim_cur = rlim->rlim_cur;
if (rlim->rlim_max == RLIM_INFINITY)
rlim64->rlim_max = RLIM64_INFINITY;
else
rlim64->rlim_max = rlim->rlim_max;
}
static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
{
if (rlim64_is_infinity(rlim64->rlim_cur))
rlim->rlim_cur = RLIM_INFINITY;
else
rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
if (rlim64_is_infinity(rlim64->rlim_max))
rlim->rlim_max = RLIM_INFINITY;
else
rlim->rlim_max = (unsigned long)rlim64->rlim_max;
}
/* make sure you are allowed to change @tsk limits before calling this */
int do_prlimit(struct task_struct *tsk, unsigned int resource,
struct rlimit *new_rlim, struct rlimit *old_rlim)
{
struct rlimit *rlim;
int retval = 0;
if (resource >= RLIM_NLIMITS)
return -EINVAL;
if (new_rlim) {
if (new_rlim->rlim_cur > new_rlim->rlim_max)
return -EINVAL;
if (resource == RLIMIT_NOFILE &&
new_rlim->rlim_max > sysctl_nr_open)
return -EPERM;
}
/* protect tsk->signal and tsk->sighand from disappearing */
read_lock(&tasklist_lock);
if (!tsk->sighand) {
retval = -ESRCH;
goto out;
}
rlim = tsk->signal->rlim + resource;
task_lock(tsk->group_leader);
if (new_rlim) {
/* Keep the capable check against init_user_ns until
cgroups can contain all limits */
if (new_rlim->rlim_max > rlim->rlim_max &&
!capable(CAP_SYS_RESOURCE))
retval = -EPERM;
if (!retval)
retval = security_task_setrlimit(tsk, resource, new_rlim);
}
if (!retval) {
if (old_rlim)
*old_rlim = *rlim;
if (new_rlim)
*rlim = *new_rlim;
}
task_unlock(tsk->group_leader);
/*
* RLIMIT_CPU handling. Arm the posix CPU timer if the limit is not
* infite. In case of RLIM_INFINITY the posix CPU timer code
* ignores the rlimit.
*/
if (!retval && new_rlim && resource == RLIMIT_CPU &&
new_rlim->rlim_cur != RLIM_INFINITY &&
IS_ENABLED(CONFIG_POSIX_TIMERS))
update_rlimit_cpu(tsk, new_rlim->rlim_cur);
out:
read_unlock(&tasklist_lock);
return retval;
}
/* rcu lock must be held */
static int check_prlimit_permission(struct task_struct *task,
unsigned int flags)
{
const struct cred *cred = current_cred(), *tcred;
bool id_match;
if (current == task)
return 0;
tcred = __task_cred(task);
id_match = (uid_eq(cred->uid, tcred->euid) &&
uid_eq(cred->uid, tcred->suid) &&
uid_eq(cred->uid, tcred->uid) &&
gid_eq(cred->gid, tcred->egid) &&
gid_eq(cred->gid, tcred->sgid) &&
gid_eq(cred->gid, tcred->gid));
if (!id_match && !ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
return -EPERM;
return security_task_prlimit(cred, tcred, flags);
}
SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
const struct rlimit64 __user *, new_rlim,
struct rlimit64 __user *, old_rlim)
{
struct rlimit64 old64, new64;
struct rlimit old, new;
struct task_struct *tsk;
unsigned int checkflags = 0;
int ret;
if (old_rlim)
checkflags |= LSM_PRLIMIT_READ;
if (new_rlim) {
if (copy_from_user(&new64, new_rlim, sizeof(new64)))
return -EFAULT;
rlim64_to_rlim(&new64, &new);
checkflags |= LSM_PRLIMIT_WRITE;
}
rcu_read_lock();
tsk = pid ? find_task_by_vpid(pid) : current;
if (!tsk) {
rcu_read_unlock();
return -ESRCH;
}
ret = check_prlimit_permission(tsk, checkflags);
if (ret) {
rcu_read_unlock();
return ret;
}
get_task_struct(tsk);
rcu_read_unlock();
ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
old_rlim ? &old : NULL);
if (!ret && old_rlim) {
rlim_to_rlim64(&old, &old64);
if (copy_to_user(old_rlim, &old64, sizeof(old64)))
ret = -EFAULT;
}
put_task_struct(tsk);
return ret;
}
SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
{
struct rlimit new_rlim;
if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
return -EFAULT;
return do_prlimit(current, resource, &new_rlim, NULL);
}
/*
* It would make sense to put struct rusage in the task_struct,
* except that would make the task_struct be *really big*. After
* task_struct gets moved into malloc'ed memory, it would
* make sense to do this. It will make moving the rest of the information
* a lot simpler! (Which we're not doing right now because we're not
* measuring them yet).
*
* When sampling multiple threads for RUSAGE_SELF, under SMP we might have
* races with threads incrementing their own counters. But since word
* reads are atomic, we either get new values or old values and we don't
* care which for the sums. We always take the siglock to protect reading
* the c* fields from p->signal from races with exit.c updating those
* fields when reaping, so a sample either gets all the additions of a
* given child after it's reaped, or none so this sample is before reaping.
*
* Locking:
* We need to take the siglock for CHILDEREN, SELF and BOTH
* for the cases current multithreaded, non-current single threaded
* non-current multithreaded. Thread traversal is now safe with
* the siglock held.
* Strictly speaking, we donot need to take the siglock if we are current and
* single threaded, as no one else can take our signal_struct away, no one
* else can reap the children to update signal->c* counters, and no one else
* can race with the signal-> fields. If we do not take any lock, the
* signal-> fields could be read out of order while another thread was just
* exiting. So we should place a read memory barrier when we avoid the lock.
* On the writer side, write memory barrier is implied in __exit_signal
* as __exit_signal releases the siglock spinlock after updating the signal->
* fields. But we don't do this yet to keep things simple.
*
*/
static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
{
r->ru_nvcsw += t->nvcsw;
r->ru_nivcsw += t->nivcsw;
r->ru_minflt += t->min_flt;
r->ru_majflt += t->maj_flt;
r->ru_inblock += task_io_get_inblock(t);
r->ru_oublock += task_io_get_oublock(t);
}
void getrusage(struct task_struct *p, int who, struct rusage *r)
{
struct task_struct *t;
unsigned long flags;
u64 tgutime, tgstime, utime, stime;
unsigned long maxrss = 0;
memset((char *)r, 0, sizeof (*r));
utime = stime = 0;
if (who == RUSAGE_THREAD) {
task_cputime_adjusted(current, &utime, &stime);
accumulate_thread_rusage(p, r);
maxrss = p->signal->maxrss;
goto out;
}
if (!lock_task_sighand(p, &flags))
return;
switch (who) {
case RUSAGE_BOTH:
case RUSAGE_CHILDREN:
utime = p->signal->cutime;
stime = p->signal->cstime;
r->ru_nvcsw = p->signal->cnvcsw;
r->ru_nivcsw = p->signal->cnivcsw;
r->ru_minflt = p->signal->cmin_flt;
r->ru_majflt = p->signal->cmaj_flt;
r->ru_inblock = p->signal->cinblock;
r->ru_oublock = p->signal->coublock;
maxrss = p->signal->cmaxrss;
if (who == RUSAGE_CHILDREN)
break;
/* fall through */
case RUSAGE_SELF:
thread_group_cputime_adjusted(p, &tgutime, &tgstime);
utime += tgutime;
stime += tgstime;
r->ru_nvcsw += p->signal->nvcsw;
r->ru_nivcsw += p->signal->nivcsw;
r->ru_minflt += p->signal->min_flt;
r->ru_majflt += p->signal->maj_flt;
r->ru_inblock += p->signal->inblock;
r->ru_oublock += p->signal->oublock;
if (maxrss < p->signal->maxrss)
maxrss = p->signal->maxrss;
t = p;
do {
accumulate_thread_rusage(t, r);
} while_each_thread(p, t);
break;
default:
BUG();
}
unlock_task_sighand(p, &flags);
out:
r->ru_utime = ns_to_kernel_old_timeval(utime);
r->ru_stime = ns_to_kernel_old_timeval(stime);
if (who != RUSAGE_CHILDREN) {
struct mm_struct *mm = get_task_mm(p);
if (mm) {
setmax_mm_hiwater_rss(&maxrss, mm);
mmput(mm);
}
}
r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
}
SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
{
struct rusage r;
if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
who != RUSAGE_THREAD)
return -EINVAL;
getrusage(current, who, &r);
return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE2(getrusage, int, who, struct compat_rusage __user *, ru)
{
struct rusage r;
if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
who != RUSAGE_THREAD)
return -EINVAL;
getrusage(current, who, &r);
return put_compat_rusage(&r, ru);
}
#endif
SYSCALL_DEFINE1(umask, int, mask)
{
mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
return mask;
}
static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
{
struct fd exe;
struct file *old_exe, *exe_file;
struct inode *inode;
int err;
exe = fdget(fd);
if (!exe.file)
return -EBADF;
inode = file_inode(exe.file);
/*
* Because the original mm->exe_file points to executable file, make
* sure that this one is executable as well, to avoid breaking an
* overall picture.
*/
err = -EACCES;
if (!S_ISREG(inode->i_mode) || path_noexec(&exe.file->f_path))
goto exit;
err = inode_permission(inode, MAY_EXEC);
if (err)
goto exit;
/*
* Forbid mm->exe_file change if old file still mapped.
*/
exe_file = get_mm_exe_file(mm);
err = -EBUSY;
if (exe_file) {
struct vm_area_struct *vma;
mmap_read_lock(mm);
for (vma = mm->mmap; vma; vma = vma->vm_next) {
if (!vma->vm_file)
continue;
if (path_equal(&vma->vm_file->f_path,
&exe_file->f_path))
goto exit_err;
}
mmap_read_unlock(mm);
fput(exe_file);
}
err = 0;
/* set the new file, lockless */
get_file(exe.file);
old_exe = xchg(&mm->exe_file, exe.file);
if (old_exe)
fput(old_exe);
exit:
fdput(exe);
return err;
exit_err:
mmap_read_unlock(mm);
fput(exe_file);
goto exit;
}
/*
* Check arithmetic relations of passed addresses.
*
* WARNING: we don't require any capability here so be very careful
* in what is allowed for modification from userspace.
*/
static int validate_prctl_map_addr(struct prctl_mm_map *prctl_map)
{
unsigned long mmap_max_addr = TASK_SIZE;
int error = -EINVAL, i;
static const unsigned char offsets[] = {
offsetof(struct prctl_mm_map, start_code),
offsetof(struct prctl_mm_map, end_code),
offsetof(struct prctl_mm_map, start_data),
offsetof(struct prctl_mm_map, end_data),
offsetof(struct prctl_mm_map, start_brk),
offsetof(struct prctl_mm_map, brk),
offsetof(struct prctl_mm_map, start_stack),
offsetof(struct prctl_mm_map, arg_start),
offsetof(struct prctl_mm_map, arg_end),
offsetof(struct prctl_mm_map, env_start),
offsetof(struct prctl_mm_map, env_end),
};
/*
* Make sure the members are not somewhere outside
* of allowed address space.
*/
for (i = 0; i < ARRAY_SIZE(offsets); i++) {
u64 val = *(u64 *)((char *)prctl_map + offsets[i]);
if ((unsigned long)val >= mmap_max_addr ||
(unsigned long)val < mmap_min_addr)
goto out;
}
/*
* Make sure the pairs are ordered.
*/
#define __prctl_check_order(__m1, __op, __m2) \
((unsigned long)prctl_map->__m1 __op \
(unsigned long)prctl_map->__m2) ? 0 : -EINVAL
error = __prctl_check_order(start_code, <, end_code);
error |= __prctl_check_order(start_data,<=, end_data);
error |= __prctl_check_order(start_brk, <=, brk);
error |= __prctl_check_order(arg_start, <=, arg_end);
error |= __prctl_check_order(env_start, <=, env_end);
if (error)
goto out;
#undef __prctl_check_order
error = -EINVAL;
/*
* @brk should be after @end_data in traditional maps.
*/
if (prctl_map->start_brk <= prctl_map->end_data ||
prctl_map->brk <= prctl_map->end_data)
goto out;
/*
* Neither we should allow to override limits if they set.
*/
if (check_data_rlimit(rlimit(RLIMIT_DATA), prctl_map->brk,
prctl_map->start_brk, prctl_map->end_data,
prctl_map->start_data))
goto out;
error = 0;
out:
return error;
}
#ifdef CONFIG_CHECKPOINT_RESTORE
static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data_size)
{
struct prctl_mm_map prctl_map = { .exe_fd = (u32)-1, };
unsigned long user_auxv[AT_VECTOR_SIZE];
struct mm_struct *mm = current->mm;
int error;
BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
BUILD_BUG_ON(sizeof(struct prctl_mm_map) > 256);
if (opt == PR_SET_MM_MAP_SIZE)
return put_user((unsigned int)sizeof(prctl_map),
(unsigned int __user *)addr);
if (data_size != sizeof(prctl_map))
return -EINVAL;
if (copy_from_user(&prctl_map, addr, sizeof(prctl_map)))
return -EFAULT;
error = validate_prctl_map_addr(&prctl_map);
if (error)
return error;
if (prctl_map.auxv_size) {
/*
* Someone is trying to cheat the auxv vector.
*/
if (!prctl_map.auxv ||
prctl_map.auxv_size > sizeof(mm->saved_auxv))
return -EINVAL;
memset(user_auxv, 0, sizeof(user_auxv));
if (copy_from_user(user_auxv,
(const void __user *)prctl_map.auxv,
prctl_map.auxv_size))
return -EFAULT;
/* Last entry must be AT_NULL as specification requires */
user_auxv[AT_VECTOR_SIZE - 2] = AT_NULL;
user_auxv[AT_VECTOR_SIZE - 1] = AT_NULL;
}
if (prctl_map.exe_fd != (u32)-1) {
/*
* Make sure the caller has the rights to
* change /proc/pid/exe link: only local sys admin should
* be allowed to.
*/
if (!ns_capable(current_user_ns(), CAP_SYS_ADMIN))
return -EINVAL;
error = prctl_set_mm_exe_file(mm, prctl_map.exe_fd);
if (error)
return error;
}
/*
* arg_lock protects concurent updates but we still need mmap_lock for
* read to exclude races with sys_brk.
*/
mmap_read_lock(mm);
/*
* We don't validate if these members are pointing to
* real present VMAs because application may have correspond
* VMAs already unmapped and kernel uses these members for statistics
* output in procfs mostly, except
*
* - @start_brk/@brk which are used in do_brk but kernel lookups
* for VMAs when updating these memvers so anything wrong written
* here cause kernel to swear at userspace program but won't lead
* to any problem in kernel itself
*/
spin_lock(&mm->arg_lock);
mm->start_code = prctl_map.start_code;
mm->end_code = prctl_map.end_code;
mm->start_data = prctl_map.start_data;
mm->end_data = prctl_map.end_data;
mm->start_brk = prctl_map.start_brk;
mm->brk = prctl_map.brk;
mm->start_stack = prctl_map.start_stack;
mm->arg_start = prctl_map.arg_start;
mm->arg_end = prctl_map.arg_end;
mm->env_start = prctl_map.env_start;
mm->env_end = prctl_map.env_end;
spin_unlock(&mm->arg_lock);
/*
* Note this update of @saved_auxv is lockless thus
* if someone reads this member in procfs while we're
* updating -- it may get partly updated results. It's
* known and acceptable trade off: we leave it as is to
* not introduce additional locks here making the kernel
* more complex.
*/
if (prctl_map.auxv_size)
memcpy(mm->saved_auxv, user_auxv, sizeof(user_auxv));
mmap_read_unlock(mm);
return 0;
}
#endif /* CONFIG_CHECKPOINT_RESTORE */
static int prctl_set_auxv(struct mm_struct *mm, unsigned long addr,
unsigned long len)
{
/*
* This doesn't move the auxiliary vector itself since it's pinned to
* mm_struct, but it permits filling the vector with new values. It's
* up to the caller to provide sane values here, otherwise userspace
* tools which use this vector might be unhappy.
*/
unsigned long user_auxv[AT_VECTOR_SIZE];
if (len > sizeof(user_auxv))
return -EINVAL;
if (copy_from_user(user_auxv, (const void __user *)addr, len))
return -EFAULT;
/* Make sure the last entry is always AT_NULL */
user_auxv[AT_VECTOR_SIZE - 2] = 0;
user_auxv[AT_VECTOR_SIZE - 1] = 0;
BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
task_lock(current);
memcpy(mm->saved_auxv, user_auxv, len);
task_unlock(current);
return 0;
}
static int prctl_set_mm(int opt, unsigned long addr,
unsigned long arg4, unsigned long arg5)
{
struct mm_struct *mm = current->mm;
struct prctl_mm_map prctl_map = {
.auxv = NULL,
.auxv_size = 0,
.exe_fd = -1,
};
struct vm_area_struct *vma;
int error;
if (arg5 || (arg4 && (opt != PR_SET_MM_AUXV &&
opt != PR_SET_MM_MAP &&
opt != PR_SET_MM_MAP_SIZE)))
return -EINVAL;
#ifdef CONFIG_CHECKPOINT_RESTORE
if (opt == PR_SET_MM_MAP || opt == PR_SET_MM_MAP_SIZE)
return prctl_set_mm_map(opt, (const void __user *)addr, arg4);
#endif
if (!capable(CAP_SYS_RESOURCE))
return -EPERM;
if (opt == PR_SET_MM_EXE_FILE)
return prctl_set_mm_exe_file(mm, (unsigned int)addr);
if (opt == PR_SET_MM_AUXV)
return prctl_set_auxv(mm, addr, arg4);
if (addr >= TASK_SIZE || addr < mmap_min_addr)
return -EINVAL;
error = -EINVAL;
/*
* arg_lock protects concurent updates of arg boundaries, we need
* mmap_lock for a) concurrent sys_brk, b) finding VMA for addr
* validation.
*/
mmap_read_lock(mm);
vma = find_vma(mm, addr);
spin_lock(&mm->arg_lock);
prctl_map.start_code = mm->start_code;
prctl_map.end_code = mm->end_code;
prctl_map.start_data = mm->start_data;
prctl_map.end_data = mm->end_data;
prctl_map.start_brk = mm->start_brk;
prctl_map.brk = mm->brk;
prctl_map.start_stack = mm->start_stack;
prctl_map.arg_start = mm->arg_start;
prctl_map.arg_end = mm->arg_end;
prctl_map.env_start = mm->env_start;
prctl_map.env_end = mm->env_end;
switch (opt) {
case PR_SET_MM_START_CODE:
prctl_map.start_code = addr;
break;
case PR_SET_MM_END_CODE:
prctl_map.end_code = addr;
break;
case PR_SET_MM_START_DATA:
prctl_map.start_data = addr;
break;
case PR_SET_MM_END_DATA:
prctl_map.end_data = addr;
break;
case PR_SET_MM_START_STACK:
prctl_map.start_stack = addr;
break;
case PR_SET_MM_START_BRK:
prctl_map.start_brk = addr;
break;
case PR_SET_MM_BRK:
prctl_map.brk = addr;
break;
case PR_SET_MM_ARG_START:
prctl_map.arg_start = addr;
break;
case PR_SET_MM_ARG_END:
prctl_map.arg_end = addr;
break;
case PR_SET_MM_ENV_START:
prctl_map.env_start = addr;
break;
case PR_SET_MM_ENV_END:
prctl_map.env_end = addr;
break;
default:
goto out;
}
error = validate_prctl_map_addr(&prctl_map);
if (error)
goto out;
switch (opt) {
/*
* If command line arguments and environment
* are placed somewhere else on stack, we can
* set them up here, ARG_START/END to setup
* command line argumets and ENV_START/END
* for environment.
*/
case PR_SET_MM_START_STACK:
case PR_SET_MM_ARG_START:
case PR_SET_MM_ARG_END:
case PR_SET_MM_ENV_START:
case PR_SET_MM_ENV_END:
if (!vma) {
error = -EFAULT;
goto out;
}
}
mm->start_code = prctl_map.start_code;
mm->end_code = prctl_map.end_code;
mm->start_data = prctl_map.start_data;
mm->end_data = prctl_map.end_data;
mm->start_brk = prctl_map.start_brk;
mm->brk = prctl_map.brk;
mm->start_stack = prctl_map.start_stack;
mm->arg_start = prctl_map.arg_start;
mm->arg_end = prctl_map.arg_end;
mm->env_start = prctl_map.env_start;
mm->env_end = prctl_map.env_end;
error = 0;
out:
spin_unlock(&mm->arg_lock);
mmap_read_unlock(mm);
return error;
}
#ifdef CONFIG_CHECKPOINT_RESTORE
static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
{
return put_user(me->clear_child_tid, tid_addr);
}
#else
static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
{
return -EINVAL;
}
#endif
static int propagate_has_child_subreaper(struct task_struct *p, void *data)
{
/*
* If task has has_child_subreaper - all its decendants
* already have these flag too and new decendants will
* inherit it on fork, skip them.
*
* If we've found child_reaper - skip descendants in
* it's subtree as they will never get out pidns.
*/
if (p->signal->has_child_subreaper ||
is_child_reaper(task_pid(p)))
return 0;
p->signal->has_child_subreaper = 1;
return 1;
}
int __weak arch_prctl_spec_ctrl_get(struct task_struct *t, unsigned long which)
{
return -EINVAL;
}
int __weak arch_prctl_spec_ctrl_set(struct task_struct *t, unsigned long which,
unsigned long ctrl)
{
return -EINVAL;
}
#define PR_IO_FLUSHER (PF_MEMALLOC_NOIO | PF_LOCAL_THROTTLE)
SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
unsigned long, arg4, unsigned long, arg5)
{
struct task_struct *me = current;
unsigned char comm[sizeof(me->comm)];
long error;
error = security_task_prctl(option, arg2, arg3, arg4, arg5);
if (error != -ENOSYS)
return error;
error = 0;
switch (option) {
case PR_SET_PDEATHSIG:
if (!valid_signal(arg2)) {
error = -EINVAL;
break;
}
me->pdeath_signal = arg2;
break;
case PR_GET_PDEATHSIG:
error = put_user(me->pdeath_signal, (int __user *)arg2);
break;
case PR_GET_DUMPABLE:
error = get_dumpable(me->mm);
break;
case PR_SET_DUMPABLE:
if (arg2 != SUID_DUMP_DISABLE && arg2 != SUID_DUMP_USER) {
error = -EINVAL;
break;
}
set_dumpable(me->mm, arg2);
break;
case PR_SET_UNALIGN:
error = SET_UNALIGN_CTL(me, arg2);
break;
case PR_GET_UNALIGN:
error = GET_UNALIGN_CTL(me, arg2);
break;
case PR_SET_FPEMU:
error = SET_FPEMU_CTL(me, arg2);
break;
case PR_GET_FPEMU:
error = GET_FPEMU_CTL(me, arg2);
break;
case PR_SET_FPEXC:
error = SET_FPEXC_CTL(me, arg2);
break;
case PR_GET_FPEXC:
error = GET_FPEXC_CTL(me, arg2);
break;
case PR_GET_TIMING:
error = PR_TIMING_STATISTICAL;
break;
case PR_SET_TIMING:
if (arg2 != PR_TIMING_STATISTICAL)
error = -EINVAL;
break;
case PR_SET_NAME:
comm[sizeof(me->comm) - 1] = 0;
if (strncpy_from_user(comm, (char __user *)arg2,
sizeof(me->comm) - 1) < 0)
return -EFAULT;
set_task_comm(me, comm);
proc_comm_connector(me);
break;
case PR_GET_NAME:
get_task_comm(comm, me);
if (copy_to_user((char __user *)arg2, comm, sizeof(comm)))
return -EFAULT;
break;
case PR_GET_ENDIAN:
error = GET_ENDIAN(me, arg2);
break;
case PR_SET_ENDIAN:
error = SET_ENDIAN(me, arg2);
break;
case PR_GET_SECCOMP:
error = prctl_get_seccomp();
break;
case PR_SET_SECCOMP:
error = prctl_set_seccomp(arg2, (char __user *)arg3);
break;
case PR_GET_TSC:
error = GET_TSC_CTL(arg2);
break;
case PR_SET_TSC:
error = SET_TSC_CTL(arg2);
break;
case PR_TASK_PERF_EVENTS_DISABLE:
error = perf_event_task_disable();
break;
case PR_TASK_PERF_EVENTS_ENABLE:
error = perf_event_task_enable();
break;
case PR_GET_TIMERSLACK:
if (current->timer_slack_ns > ULONG_MAX)
error = ULONG_MAX;
else
error = current->timer_slack_ns;
break;
case PR_SET_TIMERSLACK:
if (arg2 <= 0)
current->timer_slack_ns =
current->default_timer_slack_ns;
else
current->timer_slack_ns = arg2;
break;
case PR_MCE_KILL:
if (arg4 | arg5)
return -EINVAL;
switch (arg2) {
case PR_MCE_KILL_CLEAR:
if (arg3 != 0)
return -EINVAL;
current->flags &= ~PF_MCE_PROCESS;
break;
case PR_MCE_KILL_SET:
current->flags |= PF_MCE_PROCESS;
if (arg3 == PR_MCE_KILL_EARLY)
current->flags |= PF_MCE_EARLY;
else if (arg3 == PR_MCE_KILL_LATE)
current->flags &= ~PF_MCE_EARLY;
else if (arg3 == PR_MCE_KILL_DEFAULT)
current->flags &=
~(PF_MCE_EARLY|PF_MCE_PROCESS);
else
return -EINVAL;
break;
default:
return -EINVAL;
}
break;
case PR_MCE_KILL_GET:
if (arg2 | arg3 | arg4 | arg5)
return -EINVAL;
if (current->flags & PF_MCE_PROCESS)
error = (current->flags & PF_MCE_EARLY) ?
PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
else
error = PR_MCE_KILL_DEFAULT;
break;
case PR_SET_MM:
error = prctl_set_mm(arg2, arg3, arg4, arg5);
break;
case PR_GET_TID_ADDRESS:
error = prctl_get_tid_address(me, (int __user **)arg2);
break;
case PR_SET_CHILD_SUBREAPER:
me->signal->is_child_subreaper = !!arg2;
if (!arg2)
break;
walk_process_tree(me, propagate_has_child_subreaper, NULL);
break;
case PR_GET_CHILD_SUBREAPER:
error = put_user(me->signal->is_child_subreaper,
(int __user *)arg2);
break;
case PR_SET_NO_NEW_PRIVS:
if (arg2 != 1 || arg3 || arg4 || arg5)
return -EINVAL;
task_set_no_new_privs(current);
break;
case PR_GET_NO_NEW_PRIVS:
if (arg2 || arg3 || arg4 || arg5)
return -EINVAL;
return task_no_new_privs(current) ? 1 : 0;
case PR_GET_THP_DISABLE:
if (arg2 || arg3 || arg4 || arg5)
return -EINVAL;
error = !!test_bit(MMF_DISABLE_THP, &me->mm->flags);
break;
case PR_SET_THP_DISABLE:
if (arg3 || arg4 || arg5)
return -EINVAL;
if (mmap_write_lock_killable(me->mm))
return -EINTR;
if (arg2)
set_bit(MMF_DISABLE_THP, &me->mm->flags);
else
clear_bit(MMF_DISABLE_THP, &me->mm->flags);
mmap_write_unlock(me->mm);
break;
case PR_MPX_ENABLE_MANAGEMENT:
case PR_MPX_DISABLE_MANAGEMENT:
/* No longer implemented: */
return -EINVAL;
case PR_SET_FP_MODE:
error = SET_FP_MODE(me, arg2);
break;
case PR_GET_FP_MODE:
error = GET_FP_MODE(me);
break;
case PR_SVE_SET_VL:
error = SVE_SET_VL(arg2);
break;
case PR_SVE_GET_VL:
error = SVE_GET_VL();
break;
case PR_GET_SPECULATION_CTRL:
if (arg3 || arg4 || arg5)
return -EINVAL;
error = arch_prctl_spec_ctrl_get(me, arg2);
break;
case PR_SET_SPECULATION_CTRL:
if (arg4 || arg5)
return -EINVAL;
error = arch_prctl_spec_ctrl_set(me, arg2, arg3);
break;
case PR_PAC_RESET_KEYS:
if (arg3 || arg4 || arg5)
return -EINVAL;
error = PAC_RESET_KEYS(me, arg2);
break;
case PR_SET_TAGGED_ADDR_CTRL:
if (arg3 || arg4 || arg5)
return -EINVAL;
error = SET_TAGGED_ADDR_CTRL(arg2);
break;
case PR_GET_TAGGED_ADDR_CTRL:
if (arg2 || arg3 || arg4 || arg5)
return -EINVAL;
error = GET_TAGGED_ADDR_CTRL();
break;
case PR_SET_IO_FLUSHER:
if (!capable(CAP_SYS_RESOURCE))
return -EPERM;
if (arg3 || arg4 || arg5)
return -EINVAL;
if (arg2 == 1)
current->flags |= PR_IO_FLUSHER;
else if (!arg2)
current->flags &= ~PR_IO_FLUSHER;
else
return -EINVAL;
break;
case PR_GET_IO_FLUSHER:
if (!capable(CAP_SYS_RESOURCE))
return -EPERM;
if (arg2 || arg3 || arg4 || arg5)
return -EINVAL;
error = (current->flags & PR_IO_FLUSHER) == PR_IO_FLUSHER;
break;
default:
error = -EINVAL;
break;
}
return error;
}
SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
struct getcpu_cache __user *, unused)
{
int err = 0;
int cpu = raw_smp_processor_id();
if (cpup)
err |= put_user(cpu, cpup);
if (nodep)
err |= put_user(cpu_to_node(cpu), nodep);
return err ? -EFAULT : 0;
}
/**
* do_sysinfo - fill in sysinfo struct
* @info: pointer to buffer to fill
*/
static int do_sysinfo(struct sysinfo *info)
{
unsigned long mem_total, sav_total;
unsigned int mem_unit, bitcount;
struct timespec64 tp;
memset(info, 0, sizeof(struct sysinfo));
ktime_get_boottime_ts64(&tp);
timens_add_boottime(&tp);
info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT);
info->procs = nr_threads;
si_meminfo(info);
si_swapinfo(info);
/*
* If the sum of all the available memory (i.e. ram + swap)
* is less than can be stored in a 32 bit unsigned long then
* we can be binary compatible with 2.2.x kernels. If not,
* well, in that case 2.2.x was broken anyways...
*
* -Erik Andersen <andersee@debian.org>
*/
mem_total = info->totalram + info->totalswap;
if (mem_total < info->totalram || mem_total < info->totalswap)
goto out;
bitcount = 0;
mem_unit = info->mem_unit;
while (mem_unit > 1) {
bitcount++;
mem_unit >>= 1;
sav_total = mem_total;
mem_total <<= 1;
if (mem_total < sav_total)
goto out;
}
/*
* If mem_total did not overflow, multiply all memory values by
* info->mem_unit and set it to 1. This leaves things compatible
* with 2.2.x, and also retains compatibility with earlier 2.4.x
* kernels...
*/
info->mem_unit = 1;
info->totalram <<= bitcount;
info->freeram <<= bitcount;
info->sharedram <<= bitcount;
info->bufferram <<= bitcount;
info->totalswap <<= bitcount;
info->freeswap <<= bitcount;
info->totalhigh <<= bitcount;
info->freehigh <<= bitcount;
out:
return 0;
}
SYSCALL_DEFINE1(sysinfo, struct sysinfo __user *, info)
{
struct sysinfo val;
do_sysinfo(&val);
if (copy_to_user(info, &val, sizeof(struct sysinfo)))
return -EFAULT;
return 0;
}
#ifdef CONFIG_COMPAT
struct compat_sysinfo {
s32 uptime;
u32 loads[3];
u32 totalram;
u32 freeram;
u32 sharedram;
u32 bufferram;
u32 totalswap;
u32 freeswap;
u16 procs;
u16 pad;
u32 totalhigh;
u32 freehigh;
u32 mem_unit;
char _f[20-2*sizeof(u32)-sizeof(int)];
};
COMPAT_SYSCALL_DEFINE1(sysinfo, struct compat_sysinfo __user *, info)
{
struct sysinfo s;
struct compat_sysinfo s_32;
do_sysinfo(&s);
/* Check to see if any memory value is too large for 32-bit and scale
* down if needed
*/
if (upper_32_bits(s.totalram) || upper_32_bits(s.totalswap)) {
int bitcount = 0;
while (s.mem_unit < PAGE_SIZE) {
s.mem_unit <<= 1;
bitcount++;
}
s.totalram >>= bitcount;
s.freeram >>= bitcount;
s.sharedram >>= bitcount;
s.bufferram >>= bitcount;
s.totalswap >>= bitcount;
s.freeswap >>= bitcount;
s.totalhigh >>= bitcount;
s.freehigh >>= bitcount;
}
memset(&s_32, 0, sizeof(s_32));
s_32.uptime = s.uptime;
s_32.loads[0] = s.loads[0];
s_32.loads[1] = s.loads[1];
s_32.loads[2] = s.loads[2];
s_32.totalram = s.totalram;
s_32.freeram = s.freeram;
s_32.sharedram = s.sharedram;
s_32.bufferram = s.bufferram;
s_32.totalswap = s.totalswap;
s_32.freeswap = s.freeswap;
s_32.procs = s.procs;
s_32.totalhigh = s.totalhigh;
s_32.freehigh = s.freehigh;
s_32.mem_unit = s.mem_unit;
if (copy_to_user(info, &s_32, sizeof(s_32)))
return -EFAULT;
return 0;
}
#endif /* CONFIG_COMPAT */
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