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/*
* linux/kernel/sys.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/utsname.h>
#include <linux/mman.h>
#include <linux/smp_lock.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/prctl.h>
#include <linux/init.h>
#include <linux/highuid.h>
#include <asm/uaccess.h>
#include <asm/io.h>
/*
* 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;
/*
* 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;
/*
* this indicates whether you can reboot with ctrl-alt-del: the default is yes
*/
int C_A_D = 1;
int cad_pid = 1;
/*
* Notifier list for kernel code which wants to be called
* at shutdown. This is used to stop any idling DMA operations
* and the like.
*/
static struct notifier_block *reboot_notifier_list;
rwlock_t notifier_lock = RW_LOCK_UNLOCKED;
/**
* notifier_chain_register - Add notifier to a notifier chain
* @list: Pointer to root list pointer
* @n: New entry in notifier chain
*
* Adds a notifier to a notifier chain.
*
* Currently always returns zero.
*/
int notifier_chain_register(struct notifier_block **list, struct notifier_block *n)
{
write_lock(¬ifier_lock);
while(*list)
{
if(n->priority > (*list)->priority)
break;
list= &((*list)->next);
}
n->next = *list;
*list=n;
write_unlock(¬ifier_lock);
return 0;
}
/**
* notifier_chain_unregister - Remove notifier from a notifier chain
* @nl: Pointer to root list pointer
* @n: New entry in notifier chain
*
* Removes a notifier from a notifier chain.
*
* Returns zero on success, or %-ENOENT on failure.
*/
int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n)
{
write_lock(¬ifier_lock);
while((*nl)!=NULL)
{
if((*nl)==n)
{
*nl=n->next;
write_unlock(¬ifier_lock);
return 0;
}
nl=&((*nl)->next);
}
write_unlock(¬ifier_lock);
return -ENOENT;
}
/**
* notifier_call_chain - Call functions in a notifier chain
* @n: Pointer to root pointer of notifier chain
* @val: Value passed unmodified to notifier function
* @v: Pointer passed unmodified to notifier function
*
* Calls each function in a notifier chain in turn.
*
* If the return value of the notifier can be and'd
* with %NOTIFY_STOP_MASK, then notifier_call_chain
* will return immediately, with the return value of
* the notifier function which halted execution.
* Otherwise, the return value is the return value
* of the last notifier function called.
*/
int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v)
{
int ret=NOTIFY_DONE;
struct notifier_block *nb = *n;
while(nb)
{
ret=nb->notifier_call(nb,val,v);
if(ret&NOTIFY_STOP_MASK)
{
return ret;
}
nb=nb->next;
}
return ret;
}
/**
* register_reboot_notifier - Register function to be called at reboot time
* @nb: Info about notifier function to be called
*
* Registers a function with the list of functions
* to be called at reboot time.
*
* Currently always returns zero, as notifier_chain_register
* always returns zero.
*/
int register_reboot_notifier(struct notifier_block * nb)
{
return notifier_chain_register(&reboot_notifier_list, nb);
}
/**
* unregister_reboot_notifier - Unregister previously registered reboot notifier
* @nb: Hook to be unregistered
*
* Unregisters a previously registered reboot
* notifier function.
*
* Returns zero on success, or %-ENOENT on failure.
*/
int unregister_reboot_notifier(struct notifier_block * nb)
{
return notifier_chain_unregister(&reboot_notifier_list, nb);
}
asmlinkage long sys_ni_syscall(void)
{
return -ENOSYS;
}
static int proc_sel(struct task_struct *p, int which, int who)
{
if(p->pid)
{
switch (which) {
case PRIO_PROCESS:
if (!who && p == current)
return 1;
return(p->pid == who);
case PRIO_PGRP:
if (!who)
who = current->pgrp;
return(p->pgrp == who);
case PRIO_USER:
if (!who)
who = current->uid;
return(p->uid == who);
}
}
return 0;
}
asmlinkage long sys_setpriority(int which, int who, int niceval)
{
struct task_struct *p;
int error;
if (which > 2 || which < 0)
return -EINVAL;
/* normalize: avoid signed division (rounding problems) */
error = -ESRCH;
if (niceval < -20)
niceval = -20;
if (niceval > 19)
niceval = 19;
read_lock(&tasklist_lock);
for_each_task(p) {
if (!proc_sel(p, which, who))
continue;
if (p->uid != current->euid &&
p->uid != current->uid && !capable(CAP_SYS_NICE)) {
error = -EPERM;
continue;
}
if (error == -ESRCH)
error = 0;
if (niceval < p->nice && !capable(CAP_SYS_NICE))
error = -EACCES;
else
p->nice = niceval;
}
read_unlock(&tasklist_lock);
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.
*/
asmlinkage long sys_getpriority(int which, int who)
{
struct task_struct *p;
long retval = -ESRCH;
if (which > 2 || which < 0)
return -EINVAL;
read_lock(&tasklist_lock);
for_each_task (p) {
long niceval;
if (!proc_sel(p, which, who))
continue;
niceval = 20 - p->nice;
if (niceval > retval)
retval = niceval;
}
read_unlock(&tasklist_lock);
return retval;
}
/*
* Reboot system call: for obvious reasons only root may call it,
* and even root needs to set up some magic numbers in the registers
* so that some mistake won't make this reboot the whole machine.
* You can also set the meaning of the ctrl-alt-del-key here.
*
* reboot doesn't sync: do that yourself before calling this.
*/
asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void * arg)
{
char buffer[256];
/* We only trust the superuser with rebooting the system. */
if (!capable(CAP_SYS_BOOT))
return -EPERM;
/* For safety, we require "magic" arguments. */
if (magic1 != LINUX_REBOOT_MAGIC1 ||
(magic2 != LINUX_REBOOT_MAGIC2 && magic2 != LINUX_REBOOT_MAGIC2A &&
magic2 != LINUX_REBOOT_MAGIC2B))
return -EINVAL;
lock_kernel();
switch (cmd) {
case LINUX_REBOOT_CMD_RESTART:
notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
printk(KERN_EMERG "Restarting system.\n");
machine_restart(NULL);
break;
case LINUX_REBOOT_CMD_CAD_ON:
C_A_D = 1;
break;
case LINUX_REBOOT_CMD_CAD_OFF:
C_A_D = 0;
break;
case LINUX_REBOOT_CMD_HALT:
notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL);
printk(KERN_EMERG "System halted.\n");
machine_halt();
do_exit(0);
break;
case LINUX_REBOOT_CMD_POWER_OFF:
notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL);
printk(KERN_EMERG "Power down.\n");
machine_power_off();
do_exit(0);
break;
case LINUX_REBOOT_CMD_RESTART2:
if (strncpy_from_user(&buffer[0], (char *)arg, sizeof(buffer) - 1) < 0) {
unlock_kernel();
return -EFAULT;
}
buffer[sizeof(buffer) - 1] = '\0';
notifier_call_chain(&reboot_notifier_list, SYS_RESTART, buffer);
printk(KERN_EMERG "Restarting system with command '%s'.\n", buffer);
machine_restart(buffer);
break;
default:
unlock_kernel();
return -EINVAL;
}
unlock_kernel();
return 0;
}
static void deferred_cad(void *dummy)
{
notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
machine_restart(NULL);
}
/*
* This function gets called by ctrl-alt-del - ie the keyboard interrupt.
* As it's called within an interrupt, it may NOT sync: the only choice
* is whether to reboot at once, or just ignore the ctrl-alt-del.
*/
void ctrl_alt_del(void)
{
static struct tq_struct cad_tq = {
routine: deferred_cad,
};
if (C_A_D)
schedule_task(&cad_tq);
else
kill_proc(cad_pid, SIGINT, 1);
}
/*
* 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).
*/
asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
{
int old_rgid = current->gid;
int old_egid = current->egid;
int new_rgid = old_rgid;
int new_egid = old_egid;
if (rgid != (gid_t) -1) {
if ((old_rgid == rgid) ||
(current->egid==rgid) ||
capable(CAP_SETGID))
new_rgid = rgid;
else
return -EPERM;
}
if (egid != (gid_t) -1) {
if ((old_rgid == egid) ||
(current->egid == egid) ||
(current->sgid == egid) ||
capable(CAP_SETGID))
new_egid = egid;
else {
return -EPERM;
}
}
if (new_egid != old_egid)
{
current->mm->dumpable = 0;
wmb();
}
if (rgid != (gid_t) -1 ||
(egid != (gid_t) -1 && egid != old_rgid))
current->sgid = new_egid;
current->fsgid = new_egid;
current->egid = new_egid;
current->gid = new_rgid;
return 0;
}
/*
* setgid() is implemented like SysV w/ SAVED_IDS
*
* SMP: Same implicit races as above.
*/
asmlinkage long sys_setgid(gid_t gid)
{
int old_egid = current->egid;
if (capable(CAP_SETGID))
{
if(old_egid != gid)
{
current->mm->dumpable=0;
wmb();
}
current->gid = current->egid = current->sgid = current->fsgid = gid;
}
else if ((gid == current->gid) || (gid == current->sgid))
{
if(old_egid != gid)
{
current->mm->dumpable=0;
wmb();
}
current->egid = current->fsgid = gid;
}
else
return -EPERM;
return 0;
}
/*
* cap_emulate_setxuid() fixes the effective / permitted capabilities of
* a process after a call to setuid, setreuid, or setresuid.
*
* 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of
* {r,e,s}uid != 0, the permitted and effective capabilities are
* cleared.
*
* 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective
* capabilities of the process are cleared.
*
* 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective
* capabilities are set to the permitted capabilities.
*
* fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
* never happen.
*
* -astor
*
* cevans - New behaviour, Oct '99
* A process may, via prctl(), elect to keep its capabilities when it
* calls setuid() and switches away from uid==0. Both permitted and
* effective sets will be retained.
* Without this change, it was impossible for a daemon to drop only some
* of its privilege. The call to setuid(!=0) would drop all privileges!
* Keeping uid 0 is not an option because uid 0 owns too many vital
* files..
* Thanks to Olaf Kirch and Peter Benie for spotting this.
*/
static inline void cap_emulate_setxuid(int old_ruid, int old_euid,
int old_suid)
{
if ((old_ruid == 0 || old_euid == 0 || old_suid == 0) &&
(current->uid != 0 && current->euid != 0 && current->suid != 0) &&
!current->keep_capabilities) {
cap_clear(current->cap_permitted);
cap_clear(current->cap_effective);
}
if (old_euid == 0 && current->euid != 0) {
cap_clear(current->cap_effective);
}
if (old_euid != 0 && current->euid == 0) {
current->cap_effective = current->cap_permitted;
}
}
static int set_user(uid_t new_ruid, int dumpclear)
{
struct user_struct *new_user, *old_user;
/* What if a process setreuid()'s and this brings the
* new uid over his NPROC rlimit? We can check this now
* cheaply with the new uid cache, so if it matters
* we should be checking for it. -DaveM
*/
new_user = alloc_uid(new_ruid);
if (!new_user)
return -EAGAIN;
old_user = current->user;
atomic_dec(&old_user->processes);
atomic_inc(&new_user->processes);
if(dumpclear)
{
current->mm->dumpable = 0;
wmb();
}
current->uid = new_ruid;
current->user = new_user;
free_uid(old_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.
*/
asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
{
int old_ruid, old_euid, old_suid, new_ruid, new_euid;
new_ruid = old_ruid = current->uid;
new_euid = old_euid = current->euid;
old_suid = current->suid;
if (ruid != (uid_t) -1) {
new_ruid = ruid;
if ((old_ruid != ruid) &&
(current->euid != ruid) &&
!capable(CAP_SETUID))
return -EPERM;
}
if (euid != (uid_t) -1) {
new_euid = euid;
if ((old_ruid != euid) &&
(current->euid != euid) &&
(current->suid != euid) &&
!capable(CAP_SETUID))
return -EPERM;
}
if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
return -EAGAIN;
if (new_euid != old_euid)
{
current->mm->dumpable=0;
wmb();
}
current->fsuid = current->euid = new_euid;
if (ruid != (uid_t) -1 ||
(euid != (uid_t) -1 && euid != old_ruid))
current->suid = current->euid;
current->fsuid = current->euid;
if (!issecure(SECURE_NO_SETUID_FIXUP)) {
cap_emulate_setxuid(old_ruid, old_euid, old_suid);
}
return 0;
}
/*
* 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.
*/
asmlinkage long sys_setuid(uid_t uid)
{
int old_euid = current->euid;
int old_ruid, old_suid, new_ruid, new_suid;
old_ruid = new_ruid = current->uid;
old_suid = current->suid;
new_suid = old_suid;
if (capable(CAP_SETUID)) {
if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
return -EAGAIN;
new_suid = uid;
} else if ((uid != current->uid) && (uid != new_suid))
return -EPERM;
if (old_euid != uid)
{
current->mm->dumpable = 0;
wmb();
}
current->fsuid = current->euid = uid;
current->suid = new_suid;
if (!issecure(SECURE_NO_SETUID_FIXUP)) {
cap_emulate_setxuid(old_ruid, old_euid, old_suid);
}
return 0;
}
/*
* This function implements a generic ability to update ruid, euid,
* and suid. This allows you to implement the 4.4 compatible seteuid().
*/
asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
{
int old_ruid = current->uid;
int old_euid = current->euid;
int old_suid = current->suid;
if (!capable(CAP_SETUID)) {
if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
(ruid != current->euid) && (ruid != current->suid))
return -EPERM;
if ((euid != (uid_t) -1) && (euid != current->uid) &&
(euid != current->euid) && (euid != current->suid))
return -EPERM;
if ((suid != (uid_t) -1) && (suid != current->uid) &&
(suid != current->euid) && (suid != current->suid))
return -EPERM;
}
if (ruid != (uid_t) -1) {
if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
return -EAGAIN;
}
if (euid != (uid_t) -1) {
if (euid != current->euid)
{
current->mm->dumpable = 0;
wmb();
}
current->euid = euid;
current->fsuid = euid;
}
if (suid != (uid_t) -1)
current->suid = suid;
if (!issecure(SECURE_NO_SETUID_FIXUP)) {
cap_emulate_setxuid(old_ruid, old_euid, old_suid);
}
return 0;
}
asmlinkage long sys_getresuid(uid_t *ruid, uid_t *euid, uid_t *suid)
{
int retval;
if (!(retval = put_user(current->uid, ruid)) &&
!(retval = put_user(current->euid, euid)))
retval = put_user(current->suid, suid);
return retval;
}
/*
* Same as above, but for rgid, egid, sgid.
*/
asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
{
if (!capable(CAP_SETGID)) {
if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
(rgid != current->egid) && (rgid != current->sgid))
return -EPERM;
if ((egid != (gid_t) -1) && (egid != current->gid) &&
(egid != current->egid) && (egid != current->sgid))
return -EPERM;
if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
(sgid != current->egid) && (sgid != current->sgid))
return -EPERM;
}
if (egid != (gid_t) -1) {
if (egid != current->egid)
{
current->mm->dumpable = 0;
wmb();
}
current->egid = egid;
current->fsgid = egid;
}
if (rgid != (gid_t) -1)
current->gid = rgid;
if (sgid != (gid_t) -1)
current->sgid = sgid;
return 0;
}
asmlinkage long sys_getresgid(gid_t *rgid, gid_t *egid, gid_t *sgid)
{
int retval;
if (!(retval = put_user(current->gid, rgid)) &&
!(retval = put_user(current->egid, egid)))
retval = put_user(current->sgid, sgid);
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..
*/
asmlinkage long sys_setfsuid(uid_t uid)
{
int old_fsuid;
old_fsuid = current->fsuid;
if (uid == current->uid || uid == current->euid ||
uid == current->suid || uid == current->fsuid ||
capable(CAP_SETUID))
{
if (uid != old_fsuid)
{
current->mm->dumpable = 0;
wmb();
}
current->fsuid = uid;
}
/* We emulate fsuid by essentially doing a scaled-down version
* of what we did in setresuid and friends. However, we only
* operate on the fs-specific bits of the process' effective
* capabilities
*
* FIXME - is fsuser used for all CAP_FS_MASK capabilities?
* if not, we might be a bit too harsh here.
*/
if (!issecure(SECURE_NO_SETUID_FIXUP)) {
if (old_fsuid == 0 && current->fsuid != 0) {
cap_t(current->cap_effective) &= ~CAP_FS_MASK;
}
if (old_fsuid != 0 && current->fsuid == 0) {
cap_t(current->cap_effective) |=
(cap_t(current->cap_permitted) & CAP_FS_MASK);
}
}
return old_fsuid;
}
/*
* Samma på svenska..
*/
asmlinkage long sys_setfsgid(gid_t gid)
{
int old_fsgid;
old_fsgid = current->fsgid;
if (gid == current->gid || gid == current->egid ||
gid == current->sgid || gid == current->fsgid ||
capable(CAP_SETGID))
{
if (gid != old_fsgid)
{
current->mm->dumpable = 0;
wmb();
}
current->fsgid = gid;
}
return old_fsgid;
}
asmlinkage long sys_times(struct tms * tbuf)
{
/*
* In the SMP world we might just be unlucky and have one of
* the times increment as we use it. Since the value is an
* atomically safe type this is just fine. Conceptually its
* as if the syscall took an instant longer to occur.
*/
if (tbuf)
if (copy_to_user(tbuf, ¤t->times, sizeof(struct tms)))
return -EFAULT;
return jiffies;
}
/*
* 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
*
* Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
* LBT 04.03.94
*/
asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
{
struct task_struct * p;
int err = -EINVAL;
if (!pid)
pid = current->pid;
if (!pgid)
pgid = pid;
if (pgid < 0)
return -EINVAL;
/* From this point forward we keep holding onto the tasklist lock
* so that our parent does not change from under us. -DaveM
*/
read_lock(&tasklist_lock);
err = -ESRCH;
p = find_task_by_pid(pid);
if (!p)
goto out;
if (p->p_pptr == current || p->p_opptr == current) {
err = -EPERM;
if (p->session != current->session)
goto out;
err = -EACCES;
if (p->did_exec)
goto out;
} else if (p != current)
goto out;
err = -EPERM;
if (p->leader)
goto out;
if (pgid != pid) {
struct task_struct * tmp;
for_each_task (tmp) {
if (tmp->pgrp == pgid &&
tmp->session == current->session)
goto ok_pgid;
}
goto out;
}
ok_pgid:
p->pgrp = pgid;
err = 0;
out:
/* All paths lead to here, thus we are safe. -DaveM */
read_unlock(&tasklist_lock);
return err;
}
asmlinkage long sys_getpgid(pid_t pid)
{
if (!pid) {
return current->pgrp;
} else {
int retval;
struct task_struct *p;
read_lock(&tasklist_lock);
p = find_task_by_pid(pid);
retval = -ESRCH;
if (p)
retval = p->pgrp;
read_unlock(&tasklist_lock);
return retval;
}
}
asmlinkage long sys_getpgrp(void)
{
/* SMP - assuming writes are word atomic this is fine */
return current->pgrp;
}
asmlinkage long sys_getsid(pid_t pid)
{
if (!pid) {
return current->session;
} else {
int retval;
struct task_struct *p;
read_lock(&tasklist_lock);
p = find_task_by_pid(pid);
retval = -ESRCH;
if(p)
retval = p->session;
read_unlock(&tasklist_lock);
return retval;
}
}
asmlinkage long sys_setsid(void)
{
struct task_struct * p;
int err = -EPERM;
read_lock(&tasklist_lock);
for_each_task(p) {
if (p->pgrp == current->pid)
goto out;
}
current->leader = 1;
current->session = current->pgrp = current->pid;
current->tty = NULL;
current->tty_old_pgrp = 0;
err = current->pgrp;
out:
read_unlock(&tasklist_lock);
return err;
}
/*
* Supplementary group IDs
*/
asmlinkage long sys_getgroups(int gidsetsize, gid_t *grouplist)
{
int i;
/*
* SMP: Nobody else can change our grouplist. Thus we are
* safe.
*/
if (gidsetsize < 0)
return -EINVAL;
i = current->ngroups;
if (gidsetsize) {
if (i > gidsetsize)
return -EINVAL;
if (copy_to_user(grouplist, current->groups, sizeof(gid_t)*i))
return -EFAULT;
}
return i;
}
/*
* SMP: Our groups are not shared. We can copy to/from them safely
* without another task interfering.
*/
asmlinkage long sys_setgroups(int gidsetsize, gid_t *grouplist)
{
if (!capable(CAP_SETGID))
return -EPERM;
if ((unsigned) gidsetsize > NGROUPS)
return -EINVAL;
if(copy_from_user(current->groups, grouplist, gidsetsize * sizeof(gid_t)))
return -EFAULT;
current->ngroups = gidsetsize;
return 0;
}
static int supplemental_group_member(gid_t grp)
{
int i = current->ngroups;
if (i) {
gid_t *groups = current->groups;
do {
if (*groups == grp)
return 1;
groups++;
i--;
} while (i);
}
return 0;
}
/*
* Check whether we're fsgid/egid or in the supplemental group..
*/
int in_group_p(gid_t grp)
{
int retval = 1;
if (grp != current->fsgid)
retval = supplemental_group_member(grp);
return retval;
}
int in_egroup_p(gid_t grp)
{
int retval = 1;
if (grp != current->egid)
retval = supplemental_group_member(grp);
return retval;
}
DECLARE_RWSEM(uts_sem);
asmlinkage long sys_newuname(struct new_utsname * name)
{
int errno = 0;
down_read(&uts_sem);
if (copy_to_user(name,&system_utsname,sizeof *name))
errno = -EFAULT;
up_read(&uts_sem);
return errno;
}
asmlinkage long sys_sethostname(char *name, int len)
{
int errno;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (len < 0 || len > __NEW_UTS_LEN)
return -EINVAL;
down_write(&uts_sem);
errno = -EFAULT;
if (!copy_from_user(system_utsname.nodename, name, len)) {
system_utsname.nodename[len] = 0;
errno = 0;
}
up_write(&uts_sem);
return errno;
}
asmlinkage long sys_gethostname(char *name, int len)
{
int i, errno;
if (len < 0)
return -EINVAL;
down_read(&uts_sem);
i = 1 + strlen(system_utsname.nodename);
if (i > len)
i = len;
errno = 0;
if (copy_to_user(name, system_utsname.nodename, i))
errno = -EFAULT;
up_read(&uts_sem);
return errno;
}
/*
* Only setdomainname; getdomainname can be implemented by calling
* uname()
*/
asmlinkage long sys_setdomainname(char *name, int len)
{
int errno;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (len < 0 || len > __NEW_UTS_LEN)
return -EINVAL;
down_write(&uts_sem);
errno = -EFAULT;
if (!copy_from_user(system_utsname.domainname, name, len)) {
errno = 0;
system_utsname.domainname[len] = 0;
}
up_write(&uts_sem);
return errno;
}
asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit *rlim)
{
if (resource >= RLIM_NLIMITS)
return -EINVAL;
else
return copy_to_user(rlim, current->rlim + resource, sizeof(*rlim))
? -EFAULT : 0;
}
#if !defined(__ia64__)
/*
* Back compatibility for getrlimit. Needed for some apps.
*/
asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit *rlim)
{
struct rlimit x;
if (resource >= RLIM_NLIMITS)
return -EINVAL;
memcpy(&x, current->rlim + resource, sizeof(*rlim));
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
asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit *rlim)
{
struct rlimit new_rlim, *old_rlim;
if (resource >= RLIM_NLIMITS)
return -EINVAL;
if(copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
return -EFAULT;
old_rlim = current->rlim + resource;
if (((new_rlim.rlim_cur > old_rlim->rlim_max) ||
(new_rlim.rlim_max > old_rlim->rlim_max)) &&
!capable(CAP_SYS_RESOURCE))
return -EPERM;
if (resource == RLIMIT_NOFILE) {
if (new_rlim.rlim_cur > NR_OPEN || new_rlim.rlim_max > NR_OPEN)
return -EPERM;
}
*old_rlim = new_rlim;
return 0;
}
/*
* 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).
*
* This is SMP safe. Either we are called from sys_getrusage on ourselves
* below (we know we aren't going to exit/disappear and only we change our
* rusage counters), or we are called from wait4() on a process which is
* either stopped or zombied. In the zombied case the task won't get
* reaped till shortly after the call to getrusage(), in both cases the
* task being examined is in a frozen state so the counters won't change.
*
* FIXME! Get the fault counts properly!
*/
int getrusage(struct task_struct *p, int who, struct rusage *ru)
{
struct rusage r;
memset((char *) &r, 0, sizeof(r));
switch (who) {
case RUSAGE_SELF:
r.ru_utime.tv_sec = CT_TO_SECS(p->times.tms_utime);
r.ru_utime.tv_usec = CT_TO_USECS(p->times.tms_utime);
r.ru_stime.tv_sec = CT_TO_SECS(p->times.tms_stime);
r.ru_stime.tv_usec = CT_TO_USECS(p->times.tms_stime);
r.ru_minflt = p->min_flt;
r.ru_majflt = p->maj_flt;
r.ru_nswap = p->nswap;
break;
case RUSAGE_CHILDREN:
r.ru_utime.tv_sec = CT_TO_SECS(p->times.tms_cutime);
r.ru_utime.tv_usec = CT_TO_USECS(p->times.tms_cutime);
r.ru_stime.tv_sec = CT_TO_SECS(p->times.tms_cstime);
r.ru_stime.tv_usec = CT_TO_USECS(p->times.tms_cstime);
r.ru_minflt = p->cmin_flt;
r.ru_majflt = p->cmaj_flt;
r.ru_nswap = p->cnswap;
break;
default:
r.ru_utime.tv_sec = CT_TO_SECS(p->times.tms_utime + p->times.tms_cutime);
r.ru_utime.tv_usec = CT_TO_USECS(p->times.tms_utime + p->times.tms_cutime);
r.ru_stime.tv_sec = CT_TO_SECS(p->times.tms_stime + p->times.tms_cstime);
r.ru_stime.tv_usec = CT_TO_USECS(p->times.tms_stime + p->times.tms_cstime);
r.ru_minflt = p->min_flt + p->cmin_flt;
r.ru_majflt = p->maj_flt + p->cmaj_flt;
r.ru_nswap = p->nswap + p->cnswap;
break;
}
return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
}
asmlinkage long sys_getrusage(int who, struct rusage *ru)
{
if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
return -EINVAL;
return getrusage(current, who, ru);
}
asmlinkage long sys_umask(int mask)
{
mask = xchg(¤t->fs->umask, mask & S_IRWXUGO);
return mask;
}
asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
unsigned long arg4, unsigned long arg5)
{
int error = 0;
int sig;
switch (option) {
case PR_SET_PDEATHSIG:
sig = arg2;
if (sig < 0 || sig > _NSIG) {
error = -EINVAL;
break;
}
current->pdeath_signal = sig;
break;
case PR_GET_PDEATHSIG:
error = put_user(current->pdeath_signal, (int *)arg2);
break;
case PR_GET_DUMPABLE:
if (current->mm->dumpable)
error = 1;
break;
case PR_SET_DUMPABLE:
if (arg2 != 0 && arg2 != 1) {
error = -EINVAL;
break;
}
current->mm->dumpable = arg2;
break;
case PR_SET_UNALIGN:
#ifdef SET_UNALIGN_CTL
error = SET_UNALIGN_CTL(current, arg2);
#else
error = -EINVAL;
#endif
break;
case PR_GET_UNALIGN:
#ifdef GET_UNALIGN_CTL
error = GET_UNALIGN_CTL(current, arg2);
#else
error = -EINVAL;
#endif
break;
case PR_SET_FPEMU:
#ifdef SET_FPEMU_CTL
error = SET_FPEMU_CTL(current, arg2);
#else
error = -EINVAL;
#endif
break;
case PR_GET_FPEMU:
#ifdef GET_FPEMU_CTL
error = GET_FPEMU_CTL(current, arg2);
#else
error = -EINVAL;
#endif
break;
case PR_GET_KEEPCAPS:
if (current->keep_capabilities)
error = 1;
break;
case PR_SET_KEEPCAPS:
if (arg2 != 0 && arg2 != 1) {
error = -EINVAL;
break;
}
current->keep_capabilities = arg2;
break;
default:
error = -EINVAL;
break;
}
return error;
}
EXPORT_SYMBOL(notifier_chain_register);
EXPORT_SYMBOL(notifier_chain_unregister);
EXPORT_SYMBOL(notifier_call_chain);
EXPORT_SYMBOL(register_reboot_notifier);
EXPORT_SYMBOL(unregister_reboot_notifier);
EXPORT_SYMBOL(in_group_p);
EXPORT_SYMBOL(in_egroup_p);
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