freebsd-dev/sys/compat/linux/linux_signal.c
Maxim Sobolev d8ff44b79f Split out kill(2) syscall service routine into user-level and kernel part, the
former is callable from user space and the latter from the kernel one. Make
kernel version take additional argument which tells if the respective call
should check for additional restrictions for sending signals to suid/sugid
applications or not.

Make all emulation layers using non-checked version, since signal numbers in
emulation layers can have different meaning that in native mode and such
protection can cause misbehaviour.

As a result remove LIBTHR from the signals allowed to be delivered to a
suid/sugid application.

Requested (sorta) by:	rwatson
MFC after:	2 weeks
2005-02-13 16:42:08 +00:00

440 lines
10 KiB
C

/*-
* Copyright (c) 1994-1995 Søren Schmidt
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
#include <sys/syscallsubr.h>
#include <sys/sysproto.h>
#include "opt_compat.h"
#ifdef COMPAT_LINUX32
#include <machine/../linux32/linux.h>
#include <machine/../linux32/linux32_proto.h>
#else
#include <machine/../linux/linux.h>
#include <machine/../linux/linux_proto.h>
#endif
#include <compat/linux/linux_signal.h>
#include <compat/linux/linux_util.h>
void
linux_to_bsd_sigset(l_sigset_t *lss, sigset_t *bss)
{
int b, l;
SIGEMPTYSET(*bss);
bss->__bits[0] = lss->__bits[0] & ~((1U << LINUX_SIGTBLSZ) - 1);
bss->__bits[1] = lss->__bits[1];
for (l = 1; l <= LINUX_SIGTBLSZ; l++) {
if (LINUX_SIGISMEMBER(*lss, l)) {
#ifdef __alpha__
b = _SIG_IDX(l);
#else
b = linux_to_bsd_signal[_SIG_IDX(l)];
#endif
if (b)
SIGADDSET(*bss, b);
}
}
}
void
bsd_to_linux_sigset(sigset_t *bss, l_sigset_t *lss)
{
int b, l;
LINUX_SIGEMPTYSET(*lss);
lss->__bits[0] = bss->__bits[0] & ~((1U << LINUX_SIGTBLSZ) - 1);
lss->__bits[1] = bss->__bits[1];
for (b = 1; b <= LINUX_SIGTBLSZ; b++) {
if (SIGISMEMBER(*bss, b)) {
#if __alpha__
l = _SIG_IDX(b);
#else
l = bsd_to_linux_signal[_SIG_IDX(b)];
#endif
if (l)
LINUX_SIGADDSET(*lss, l);
}
}
}
static void
linux_to_bsd_sigaction(l_sigaction_t *lsa, struct sigaction *bsa)
{
linux_to_bsd_sigset(&lsa->lsa_mask, &bsa->sa_mask);
bsa->sa_handler = PTRIN(lsa->lsa_handler);
bsa->sa_flags = 0;
if (lsa->lsa_flags & LINUX_SA_NOCLDSTOP)
bsa->sa_flags |= SA_NOCLDSTOP;
if (lsa->lsa_flags & LINUX_SA_NOCLDWAIT)
bsa->sa_flags |= SA_NOCLDWAIT;
if (lsa->lsa_flags & LINUX_SA_SIGINFO)
bsa->sa_flags |= SA_SIGINFO;
if (lsa->lsa_flags & LINUX_SA_ONSTACK)
bsa->sa_flags |= SA_ONSTACK;
if (lsa->lsa_flags & LINUX_SA_RESTART)
bsa->sa_flags |= SA_RESTART;
if (lsa->lsa_flags & LINUX_SA_ONESHOT)
bsa->sa_flags |= SA_RESETHAND;
if (lsa->lsa_flags & LINUX_SA_NOMASK)
bsa->sa_flags |= SA_NODEFER;
}
static void
bsd_to_linux_sigaction(struct sigaction *bsa, l_sigaction_t *lsa)
{
bsd_to_linux_sigset(&bsa->sa_mask, &lsa->lsa_mask);
#ifdef COMPAT_LINUX32
lsa->lsa_handler = (uintptr_t)bsa->sa_handler;
#else
lsa->lsa_handler = bsa->sa_handler;
#endif
lsa->lsa_restorer = 0; /* unsupported */
lsa->lsa_flags = 0;
if (bsa->sa_flags & SA_NOCLDSTOP)
lsa->lsa_flags |= LINUX_SA_NOCLDSTOP;
if (bsa->sa_flags & SA_NOCLDWAIT)
lsa->lsa_flags |= LINUX_SA_NOCLDWAIT;
if (bsa->sa_flags & SA_SIGINFO)
lsa->lsa_flags |= LINUX_SA_SIGINFO;
if (bsa->sa_flags & SA_ONSTACK)
lsa->lsa_flags |= LINUX_SA_ONSTACK;
if (bsa->sa_flags & SA_RESTART)
lsa->lsa_flags |= LINUX_SA_RESTART;
if (bsa->sa_flags & SA_RESETHAND)
lsa->lsa_flags |= LINUX_SA_ONESHOT;
if (bsa->sa_flags & SA_NODEFER)
lsa->lsa_flags |= LINUX_SA_NOMASK;
}
int
linux_do_sigaction(struct thread *td, int linux_sig, l_sigaction_t *linux_nsa,
l_sigaction_t *linux_osa)
{
struct sigaction act, oact, *nsa, *osa;
int error, sig;
if (linux_sig <= 0 || linux_sig > LINUX_NSIG)
return (EINVAL);
osa = (linux_osa != NULL) ? &oact : NULL;
if (linux_nsa != NULL) {
nsa = &act;
linux_to_bsd_sigaction(linux_nsa, nsa);
} else
nsa = NULL;
#ifndef __alpha__
if (linux_sig <= LINUX_SIGTBLSZ)
sig = linux_to_bsd_signal[_SIG_IDX(linux_sig)];
else
#endif
sig = linux_sig;
error = kern_sigaction(td, sig, nsa, osa, 0);
if (error)
return (error);
if (linux_osa != NULL)
bsd_to_linux_sigaction(osa, linux_osa);
return (0);
}
#ifndef __alpha__
int
linux_signal(struct thread *td, struct linux_signal_args *args)
{
l_sigaction_t nsa, osa;
int error;
#ifdef DEBUG
if (ldebug(signal))
printf(ARGS(signal, "%d, %p"),
args->sig, (void *)(uintptr_t)args->handler);
#endif
nsa.lsa_handler = args->handler;
nsa.lsa_flags = LINUX_SA_ONESHOT | LINUX_SA_NOMASK;
LINUX_SIGEMPTYSET(nsa.lsa_mask);
error = linux_do_sigaction(td, args->sig, &nsa, &osa);
td->td_retval[0] = (int)(intptr_t)osa.lsa_handler;
return (error);
}
#endif /*!__alpha__*/
int
linux_rt_sigaction(struct thread *td, struct linux_rt_sigaction_args *args)
{
l_sigaction_t nsa, osa;
int error;
#ifdef DEBUG
if (ldebug(rt_sigaction))
printf(ARGS(rt_sigaction, "%ld, %p, %p, %ld"),
(long)args->sig, (void *)args->act,
(void *)args->oact, (long)args->sigsetsize);
#endif
if (args->sigsetsize != sizeof(l_sigset_t))
return (EINVAL);
if (args->act != NULL) {
error = copyin(args->act, &nsa, sizeof(l_sigaction_t));
if (error)
return (error);
}
error = linux_do_sigaction(td, args->sig,
args->act ? &nsa : NULL,
args->oact ? &osa : NULL);
if (args->oact != NULL && !error) {
error = copyout(&osa, args->oact, sizeof(l_sigaction_t));
}
return (error);
}
static int
linux_do_sigprocmask(struct thread *td, int how, l_sigset_t *new,
l_sigset_t *old)
{
sigset_t omask, nmask;
sigset_t *nmaskp;
int error;
td->td_retval[0] = 0;
switch (how) {
case LINUX_SIG_BLOCK:
how = SIG_BLOCK;
break;
case LINUX_SIG_UNBLOCK:
how = SIG_UNBLOCK;
break;
case LINUX_SIG_SETMASK:
how = SIG_SETMASK;
break;
default:
return (EINVAL);
}
if (new != NULL) {
linux_to_bsd_sigset(new, &nmask);
nmaskp = &nmask;
} else
nmaskp = NULL;
error = kern_sigprocmask(td, how, nmaskp, &omask, 0);
if (error == 0 && old != NULL)
bsd_to_linux_sigset(&omask, old);
return (error);
}
#ifndef __alpha__
int
linux_sigprocmask(struct thread *td, struct linux_sigprocmask_args *args)
{
l_osigset_t mask;
l_sigset_t set, oset;
int error;
#ifdef DEBUG
if (ldebug(sigprocmask))
printf(ARGS(sigprocmask, "%d, *, *"), args->how);
#endif
if (args->mask != NULL) {
error = copyin(args->mask, &mask, sizeof(l_osigset_t));
if (error)
return (error);
LINUX_SIGEMPTYSET(set);
set.__bits[0] = mask;
}
error = linux_do_sigprocmask(td, args->how,
args->mask ? &set : NULL,
args->omask ? &oset : NULL);
if (args->omask != NULL && !error) {
mask = oset.__bits[0];
error = copyout(&mask, args->omask, sizeof(l_osigset_t));
}
return (error);
}
#endif /*!__alpha__*/
int
linux_rt_sigprocmask(struct thread *td, struct linux_rt_sigprocmask_args *args)
{
l_sigset_t set, oset;
int error;
#ifdef DEBUG
if (ldebug(rt_sigprocmask))
printf(ARGS(rt_sigprocmask, "%d, %p, %p, %ld"),
args->how, (void *)args->mask,
(void *)args->omask, (long)args->sigsetsize);
#endif
if (args->sigsetsize != sizeof(l_sigset_t))
return EINVAL;
if (args->mask != NULL) {
error = copyin(args->mask, &set, sizeof(l_sigset_t));
if (error)
return (error);
}
error = linux_do_sigprocmask(td, args->how,
args->mask ? &set : NULL,
args->omask ? &oset : NULL);
if (args->omask != NULL && !error) {
error = copyout(&oset, args->omask, sizeof(l_sigset_t));
}
return (error);
}
#ifndef __alpha__
int
linux_sgetmask(struct thread *td, struct linux_sgetmask_args *args)
{
struct proc *p = td->td_proc;
l_sigset_t mask;
#ifdef DEBUG
if (ldebug(sgetmask))
printf(ARGS(sgetmask, ""));
#endif
PROC_LOCK(p);
bsd_to_linux_sigset(&td->td_sigmask, &mask);
PROC_UNLOCK(p);
td->td_retval[0] = mask.__bits[0];
return (0);
}
int
linux_ssetmask(struct thread *td, struct linux_ssetmask_args *args)
{
struct proc *p = td->td_proc;
l_sigset_t lset;
sigset_t bset;
#ifdef DEBUG
if (ldebug(ssetmask))
printf(ARGS(ssetmask, "%08lx"), (unsigned long)args->mask);
#endif
PROC_LOCK(p);
bsd_to_linux_sigset(&td->td_sigmask, &lset);
td->td_retval[0] = lset.__bits[0];
LINUX_SIGEMPTYSET(lset);
lset.__bits[0] = args->mask;
linux_to_bsd_sigset(&lset, &bset);
td->td_sigmask = bset;
SIG_CANTMASK(td->td_sigmask);
signotify(td);
PROC_UNLOCK(p);
return (0);
}
/*
* MPSAFE
*/
int
linux_sigpending(struct thread *td, struct linux_sigpending_args *args)
{
struct proc *p = td->td_proc;
sigset_t bset;
l_sigset_t lset;
l_osigset_t mask;
#ifdef DEBUG
if (ldebug(sigpending))
printf(ARGS(sigpending, "*"));
#endif
PROC_LOCK(p);
bset = p->p_siglist;
SIGSETOR(bset, td->td_siglist);
SIGSETAND(bset, td->td_sigmask);
PROC_UNLOCK(p);
bsd_to_linux_sigset(&bset, &lset);
mask = lset.__bits[0];
return (copyout(&mask, args->mask, sizeof(mask)));
}
#endif /*!__alpha__*/
int
linux_kill(struct thread *td, struct linux_kill_args *args)
{
struct kill_args /* {
int pid;
int signum;
} */ tmp;
#ifdef DEBUG
if (ldebug(kill))
printf(ARGS(kill, "%d, %d"), args->pid, args->signum);
#endif
/*
* Allow signal 0 as a means to check for privileges
*/
if (args->signum < 0 || args->signum > LINUX_NSIG)
return EINVAL;
#ifndef __alpha__
if (args->signum > 0 && args->signum <= LINUX_SIGTBLSZ)
tmp.signum = linux_to_bsd_signal[_SIG_IDX(args->signum)];
else
#endif
tmp.signum = args->signum;
tmp.pid = args->pid;
return (kern_kill(td, &tmp, 0));
}