- 根目录:
- kernel
- sys.c
/*
* 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/mm.h>
#include <linux/mempolicy.h>
#include <linux/compat.h>
#include <linux/syscalls.h>
#include <linux/kprobes.h>
#include <linux/user_namespace.h>
#include <linux/binfmts.h>
#include <linux/sched.h>
#include <linux/rcupdate.h>
#include <linux/uidgid.h>
#include <linux/cred.h>
#include <linux/kmsg_dump.h>
/* Move somewhere else to avoid recompiling? */
#include <generated/utsrelease.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/unistd.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 MPX_ENABLE_MANAGEMENT
# define MPX_ENABLE_MANAGEMENT(a) (-EINVAL)
#endif
#ifndef MPX_DISABLE_MANAGEMENT
# define MPX_DISABLE_MANAGEMENT(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
/*
* 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_OVERFLOWUID;
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))
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)) {
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
SYSCALL_DEFINE2(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;
return commit_creds(new);
error:
abort_creds(new);
return retval;
}
/*
* setgid() is implemented like SysV w/ SAVED_IDS
*
* SMP: Same implicit races as above.
*/
SYSCALL_DEFINE1(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;
return commit_creds(new);
error:
abort_creds(new);
return retval;
}
/*
* 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.
*/
SYSCALL_DEFINE2(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(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(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;
}
/*
* 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.
*/
SYSCALL_DEFINE1(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(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;
}
/*
* This function implements a generic ability to update ruid, euid,
* and suid. This allows you to implement the 4.4 compatible seteuid().
*/
SYSCALL_DEFINE3(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(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(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.
*/
SYSCALL_DEFINE3(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;
return commit_creds(new);
error:
abort_creds(new);
return retval;
}
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..
*/
SYSCALL_DEFINE1(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(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;
}
/*
* Samma på svenska..
*/
SYSCALL_DEFINE1(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;
goto change_okay;
}
}
abort_creds(new);
return old_fsgid;
change_okay:
commit_creds(new);
return old_fsgid;
}
#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());
}
void do_sys_times(struct tms *tms)
{
cputime_t tgutime, tgstime, cutime, cstime;
thread_group_cputime_adjusted(current, &tgutime, &tgstime);
cutime = current->signal->cutime;
cstime = current->signal->cstime;
tms->tms_utime = cputime_to_clock_t(tgutime);
tms->tms_stime = cputime_to_clock_t(tgstime);
tms->tms_cutime = cputime_to_clock_t(cutime);
tms->tms_cstime = cputime_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());
}
/*
* 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;
}
SYSCALL_DEFINE1(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;
}
#ifdef __ARCH_WANT_SYS_GETPGRP
SYSCALL_DEFINE0(getpgrp)
{
return sys_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);
}
SYSCALL_DEFINE0(setsid)
{
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;
}
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 to 2.6.60+x, so 4.0 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)
{
int errno = 0;
down_read(&uts_sem);
if (copy_to_user(name, utsname(), sizeof *name))
errno = -EFAULT;
up_read(&uts_sem);
if (!errno && override_release(name->release, sizeof(name->release)))
errno = -EFAULT;
if (!errno && override_architecture(name))
errno = -EFAULT;
return errno;
}
#ifdef __ARCH_WANT_SYS_OLD_UNAME
/*
* Old cruft
*/
SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
{
int error = 0;
if (!name)
return -EFAULT;
down_read(&uts_sem);
if (copy_to_user(name, utsname(), sizeof(*name)))
error = -EFAULT;
up_read(&uts_sem);
if (!error && override_release(name->release, sizeof(name->release)))
error = -EFAULT;
if (!error && override_architecture(name))
error = -EFAULT;
return error;
}
SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
{
int error;
if (!name)
return -EFAULT;
if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
return -EFAULT;
down_read(&uts_sem);
error = __copy_to_user(&name->sysname, &utsname()->sysname,
__OLD_UTS_LEN);
error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
error |= __copy_to_user(&name->nodename, &utsname()->nodename,
__OLD_UTS_LEN);
error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
error |= __copy_to_user(&name->release, &utsname()->release,
__OLD_UTS_LEN);
error |= __put_user(0, name->release + __OLD_UTS_LEN);
error |= __copy_to_user(&name->version, &utsname()->version,
__OLD_UTS_LEN);
error |= __put_user(0, name->version + __OLD_UTS_LEN);
error |= __copy_to_user(&name->machine, &utsname()->machine,
__OLD_UTS_LEN);
error |= __put_user(0, name->machine + __OLD_UTS_LEN);
up_read(&uts_sem);
if (!error && override_architecture(name))
error = -EFAULT;
if (!error && override_release(name->release, sizeof(name->release)))
error = -EFAULT;
return error ? -EFAULT : 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;
down_write(&uts_sem);
errno = -EFAULT;
if (!copy_from_user(tmp, name, len)) {
struct new_utsname *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, errno;
struct new_utsname *u;
if (len < 0)
return -EINVAL;
down_read(&uts_sem);
u = utsname();
i = 1 + strlen(u->nodename);
if (i > len)
i = len;
errno = 0;
if (copy_to_user(name, u->nodename, i))
errno = -EFAULT;
up_read(&uts_sem);
return errno;
}
#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;
down_write(&uts_sem);
errno = -EFAULT;
if (!copy_from_user(tmp, name, len)) {
struct new_utsname *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 __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;
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;
}
#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->group_leader,
resource, new_rlim);
if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
/*
* The caller is asking for an immediate RLIMIT_CPU
* expiry. But we use the zero value to mean "it was
* never set". So let's cheat and make it one second
* instead
*/
new_rlim->rlim_cur = 1;
}
}
if (!retval) {
if (old_rlim)
*old_rlim = *rlim;
if (new_rlim)
*rlim = *new_rlim;
}
task_unlock(tsk->group_leader);
/*
* RLIMIT_CPU handling. Note that the kernel fails to return an error
* code if it rejected the user's attempt to set RLIMIT_CPU. This is a
* very long-standing error, and fixing it now risks breakage of
* applications, so we live with it
*/
if (!retval && new_rlim && resource == RLIMIT_CPU &&
new_rlim->rlim_cur != RLIM_INFINITY)
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)
{
const struct cred *cred = current_cred(), *tcred;
if (current == task)
return 0;
tcred = __task_cred(task);
if (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))
return 0;
if (ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
return 0;
return -EPERM;
}
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;
int ret;
if (new_rlim) {
if (copy_from_user(&new64, new_rlim, sizeof(new64)))
return -EFAULT;
rlim64_to_rlim(&new64, &new);
}
rcu_read_lock();
tsk = pid ? find_task_by_vpid(pid) : current;
if (!tsk) {
rcu_read_unlock();
return -ESRCH;
}
ret = check_prlimit_permission(tsk);
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);
}
static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
{
struct task_struct *t;
unsigned long flags;
cputime_t 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;
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:
cputime_to_timeval(utime, &r->ru_utime);
cputime_to_timeval(stime, &r->ru_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 */
}
int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
{
struct rusage r;
k_getrusage(p, who, &r);
return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
}
SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
{
if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
who != RUSAGE_THREAD)
return -EINVAL;
return getrusage(current, who, ru);
}
#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;
k_getrusage(current, who, &r);
return put_compat_rusage(&r, ru);
}
#endif
SYSCALL_DEFINE1(umask, int, mask)
{
mask = xchg(¤t->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) ||
exe.file->f_path.mnt->mnt_flags & MNT_NOEXEC)
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;
down_read(&mm->mmap_sem);
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;
}
up_read(&mm->mmap_sem);
fput(exe_file);
}
/*
* The symlink can be changed only once, just to disallow arbitrary
* transitions malicious software might bring in. This means one
* could make a snapshot over all processes running and monitor
* /proc/pid/exe changes to notice unusual activity if needed.
*/
err = -EPERM;
if (test_and_set_bit(MMF_EXE_FILE_CHANGED, &mm->flags))
goto exit;
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:
up_read(&mm->mmap_sem);
fput(exe_file);
goto exit;
}
#ifdef CONFIG_CHECKPOINT_RESTORE
/*
* 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(struct prctl_mm_map *prctl_map)
{
unsigned long mmap_max_addr = TASK_SIZE;
struct mm_struct *mm = current->mm;
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;
/*
* Someone is trying to cheat the auxv vector.
*/
if (prctl_map->auxv_size) {
if (!prctl_map->auxv || prctl_map->auxv_size > sizeof(mm->saved_auxv))
goto out;
}
/*
* Finally, make sure the caller has the rights to
* change /proc/pid/exe link: only local root should
* be allowed to.
*/
if (prctl_map->exe_fd != (u32)-1) {
struct user_namespace *ns = current_user_ns();
const struct cred *cred = current_cred();
if (!uid_eq(cred->uid, make_kuid(ns, 0)) ||
!gid_eq(cred->gid, make_kgid(ns, 0)))
goto out;
}
error = 0;
out:
return error;
}
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(&prctl_map);
if (error)
return error;
if (prctl_map.auxv_size) {
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)
error = prctl_set_mm_exe_file(mm, prctl_map.exe_fd);
down_read(&mm->mmap_sem);
if (error)
goto out;
/*
* 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
*/
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;
/*
* 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));
error = 0;
out:
up_read(&mm->mmap_sem);
return error;
}
#endif /* CONFIG_CHECKPOINT_RESTORE */
static int prctl_set_mm(int opt, unsigned long addr,
unsigned long arg4, unsigned long arg5)
{
struct mm_struct *mm = current->mm;
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 (addr >= TASK_SIZE || addr < mmap_min_addr)
return -EINVAL;
error = -EINVAL;
down_read(&mm->mmap_sem);
vma = find_vma(mm, addr);
switch (opt) {
case PR_SET_MM_START_CODE:
mm->start_code = addr;
break;
case PR_SET_MM_END_CODE:
mm->end_code = addr;
break;
case PR_SET_MM_START_DATA:
mm->start_data = addr;
break;
case PR_SET_MM_END_DATA:
mm->end_data = addr;
break;
case PR_SET_MM_START_BRK:
if (addr <= mm->end_data)
goto out;
if (check_data_rlimit(rlimit(RLIMIT_DATA), mm->brk, addr,
mm->end_data, mm->start_data))
goto out;
mm->start_brk = addr;
break;
case PR_SET_MM_BRK:
if (addr <= mm->end_data)
goto out;
if (check_data_rlimit(rlimit(RLIMIT_DATA), addr, mm->start_brk,
mm->end_data, mm->start_data))
goto out;
mm->brk = addr;
break;
/*
* 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;
}
if (opt == PR_SET_MM_START_STACK)
mm->start_stack = addr;
else if (opt == PR_SET_MM_ARG_START)
mm->arg_start = addr;
else if (opt == PR_SET_MM_ARG_END)
mm->arg_end = addr;
else if (opt == PR_SET_MM_ENV_START)
mm->env_start = addr;
else if (opt == PR_SET_MM_ENV_END)
mm->env_end = addr;
break;
/*
* This doesn't move auxiliary vector itself
* since it's pinned to mm_struct, but allow
* to fill vector with new values. It's up
* to a caller to provide sane values here
* otherwise user space tools which use this
* vector might be unhappy.
*/
case PR_SET_MM_AUXV: {
unsigned long user_auxv[AT_VECTOR_SIZE];
if (arg4 > sizeof(user_auxv))
goto out;
up_read(&mm->mmap_sem);
if (copy_from_user(user_auxv, (const void __user *)addr, arg4))
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, arg4);
task_unlock(current);
return 0;
}
default:
goto out;
}
error = 0;
out:
up_read(&mm->mmap_sem);
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
#ifdef CONFIG_MMU
static int prctl_update_vma_anon_name(struct vm_area_struct *vma,
struct vm_area_struct **prev,
unsigned long start, unsigned long end,
const char __user *name_addr)
{
struct mm_struct *mm = vma->vm_mm;
int error = 0;
pgoff_t pgoff;
if (name_addr == vma_get_anon_name(vma)) {
*prev = vma;
goto out;
}
pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
*prev = vma_merge(mm, *prev, start, end, vma->vm_flags, vma->anon_vma,
vma->vm_file, pgoff, vma_policy(vma),
name_addr);
if (*prev) {
vma = *prev;
goto success;
}
*prev = vma;
if (start != vma->vm_start) {
error = split_vma(mm, vma, start, 1);
if (error)
goto out;
}
if (end != vma->vm_end) {
error = split_vma(mm, vma, end, 0);
if (error)
goto out;
}
success:
if (!vma->vm_file)
vma->anon_name = name_addr;
out:
if (error == -ENOMEM)
error = -EAGAIN;
return error;
}
static int prctl_set_vma_anon_name(unsigned long start, unsigned long end,
unsigned long arg)
{
unsigned long tmp;
struct vm_area_struct *vma, *prev;
int unmapped_error = 0;
int error = -EINVAL;
/*
* If the interval [start,end) covers some unmapped address
* ranges, just ignore them, but return -ENOMEM at the end.
* - this matches the handling in madvise.
*/
vma = find_vma_prev(current->mm, start, &prev);
if (vma && start > vma->vm_start)
prev = vma;
for (;;) {
/* Still start < end. */
error = -ENOMEM;
if (!vma)
return error;
/* Here start < (end|vma->vm_end). */
if (start < vma->vm_start) {
unmapped_error = -ENOMEM;
start = vma->vm_start;
if (start >= end)
return error;
}
/* Here vma->vm_start <= start < (end|vma->vm_end) */
tmp = vma->vm_end;
if (end < tmp)
tmp = end;
/* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */
error = prctl_update_vma_anon_name(vma, &prev, start, tmp,
(const char __user *)arg);
if (error)
return error;
start = tmp;
if (prev && start < prev->vm_end)
start = prev->vm_end;
error = unmapped_error;
if (start >= end)
return error;
if (prev)
vma = prev->vm_next;
else /* madvise_remove dropped mmap_sem */
vma = find_vma(current->mm, start);
}
}
static int prctl_set_vma(unsigned long opt, unsigned long start,
unsigned long len_in, unsigned long arg)
{
struct mm_struct *mm = current->mm;
int error;
unsigned long len;
unsigned long end;
if (start & ~PAGE_MASK)
return -EINVAL;
len = (len_in + ~PAGE_MASK) & PAGE_MASK;
/* Check to see whether len was rounded up from small -ve to zero */
if (len_in && !len)
return -EINVAL;
end = start + len;
if (end < start)
return -EINVAL;
if (end == start)
return 0;
down_write(&mm->mmap_sem);
switch (opt) {
case PR_SET_VMA_ANON_NAME:
error = prctl_set_vma_anon_name(start, end, arg);
break;
default:
error = -EINVAL;
}
up_write(&mm->mmap_sem);
return error;
}
#else /* CONFIG_MMU */
static int prctl_set_vma(unsigned long opt, unsigned long start,
unsigned long len_in, unsigned long arg)
{
return -EINVAL;
}
#endif
SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
unsigned long, arg4, unsigned long, arg5)
{
struct task_struct *me = current;
struct task_struct *tsk;
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:
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_TIMERSLACK_PID:
if (task_pid_vnr(current) != (pid_t)arg3 &&
!capable(CAP_SYS_NICE))
return -EPERM;
rcu_read_lock();
tsk = find_task_by_vpid((pid_t)arg3);
if (tsk == NULL) {
rcu_read_unlock();
return -EINVAL;
}
get_task_struct(tsk);
rcu_read_unlock();
if (arg2 <= 0)
tsk->timer_slack_ns =
tsk->default_timer_slack_ns;
else
tsk->timer_slack_ns = arg2;
put_task_struct(tsk);
error = 0;
break;
case PR_SET_CHILD_SUBREAPER:
me->signal->is_child_subreaper = !!arg2;
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 = !!(me->mm->def_flags & VM_NOHUGEPAGE);
break;
case PR_SET_THP_DISABLE:
if (arg3 || arg4 || arg5)
return -EINVAL;
down_write(&me->mm->mmap_sem);
if (arg2)
me->mm->def_flags |= VM_NOHUGEPAGE;
else
me->mm->def_flags &= ~VM_NOHUGEPAGE;
up_write(&me->mm->mmap_sem);
break;
case PR_MPX_ENABLE_MANAGEMENT:
if (arg2 || arg3 || arg4 || arg5)
return -EINVAL;
error = MPX_ENABLE_MANAGEMENT(me);
break;
case PR_MPX_DISABLE_MANAGEMENT:
if (arg2 || arg3 || arg4 || arg5)
return -EINVAL;
error = MPX_DISABLE_MANAGEMENT(me);
break;
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_SET_VMA:
error = prctl_set_vma(arg2, arg3, arg4, arg5);
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 timespec tp;
memset(info, 0, sizeof(struct sysinfo));
get_monotonic_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;
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;
}
if (!access_ok(VERIFY_WRITE, info, sizeof(struct compat_sysinfo)) ||
__put_user(s.uptime, &info->uptime) ||
__put_user(s.loads[0], &info->loads[0]) ||
__put_user(s.loads[1], &info->loads[1]) ||
__put_user(s.loads[2], &info->loads[2]) ||
__put_user(s.totalram, &info->totalram) ||
__put_user(s.freeram, &info->freeram) ||
__put_user(s.sharedram, &info->sharedram) ||
__put_user(s.bufferram, &info->bufferram) ||
__put_user(s.totalswap, &info->totalswap) ||
__put_user(s.freeswap, &info->freeswap) ||
__put_user(s.procs, &info->procs) ||
__put_user(s.totalhigh, &info->totalhigh) ||
__put_user(s.freehigh, &info->freehigh) ||
__put_user(s.mem_unit, &info->mem_unit))
return -EFAULT;
return 0;
}
#endif /* CONFIG_COMPAT */