freebsd-skq/sys/i386/ibcs2/ibcs2_signal.c
sobomax 1d558007d0 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

442 lines
10 KiB
C

/*-
* Copyright (c) 1995 Scott Bartram
* Copyright (c) 1995 Steven Wallace
* 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.
* 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/signalvar.h>
#include <sys/syscallsubr.h>
#include <sys/sysproto.h>
#include <i386/ibcs2/ibcs2_types.h>
#include <i386/ibcs2/ibcs2_signal.h>
#include <i386/ibcs2/ibcs2_proto.h>
#include <i386/ibcs2/ibcs2_xenix.h>
#include <i386/ibcs2/ibcs2_util.h>
#define sigemptyset(s) SIGEMPTYSET(*(s))
#define sigismember(s, n) SIGISMEMBER(*(s), n)
#define sigaddset(s, n) SIGADDSET(*(s), n)
#define ibcs2_sigmask(n) (1 << ((n) - 1))
#define ibcs2_sigemptyset(s) bzero((s), sizeof(*(s)))
#define ibcs2_sigismember(s, n) (*(s) & ibcs2_sigmask(n))
#define ibcs2_sigaddset(s, n) (*(s) |= ibcs2_sigmask(n))
static void ibcs2_to_bsd_sigset(const ibcs2_sigset_t *, sigset_t *);
static void bsd_to_ibcs2_sigset(const sigset_t *, ibcs2_sigset_t *);
static void ibcs2_to_bsd_sigaction(struct ibcs2_sigaction *,
struct sigaction *);
static void bsd_to_ibcs2_sigaction(struct sigaction *,
struct ibcs2_sigaction *);
int bsd_to_ibcs2_sig[IBCS2_SIGTBLSZ] = {
IBCS2_SIGHUP, /* 1 */
IBCS2_SIGINT, /* 2 */
IBCS2_SIGQUIT, /* 3 */
IBCS2_SIGILL, /* 4 */
IBCS2_SIGTRAP, /* 5 */
IBCS2_SIGABRT, /* 6 */
IBCS2_SIGEMT, /* 7 */
IBCS2_SIGFPE, /* 8 */
IBCS2_SIGKILL, /* 9 */
IBCS2_SIGBUS, /* 10 */
IBCS2_SIGSEGV, /* 11 */
IBCS2_SIGSYS, /* 12 */
IBCS2_SIGPIPE, /* 13 */
IBCS2_SIGALRM, /* 14 */
IBCS2_SIGTERM, /* 15 */
0, /* 16 - SIGURG */
IBCS2_SIGSTOP, /* 17 */
IBCS2_SIGTSTP, /* 18 */
IBCS2_SIGCONT, /* 19 */
IBCS2_SIGCLD, /* 20 */
IBCS2_SIGTTIN, /* 21 */
IBCS2_SIGTTOU, /* 22 */
IBCS2_SIGPOLL, /* 23 */
0, /* 24 - SIGXCPU */
0, /* 25 - SIGXFSZ */
IBCS2_SIGVTALRM, /* 26 */
IBCS2_SIGPROF, /* 27 */
IBCS2_SIGWINCH, /* 28 */
0, /* 29 */
IBCS2_SIGUSR1, /* 30 */
IBCS2_SIGUSR2, /* 31 */
0 /* 32 */
};
static int ibcs2_to_bsd_sig[IBCS2_SIGTBLSZ] = {
SIGHUP, /* 1 */
SIGINT, /* 2 */
SIGQUIT, /* 3 */
SIGILL, /* 4 */
SIGTRAP, /* 5 */
SIGABRT, /* 6 */
SIGEMT, /* 7 */
SIGFPE, /* 8 */
SIGKILL, /* 9 */
SIGBUS, /* 10 */
SIGSEGV, /* 11 */
SIGSYS, /* 12 */
SIGPIPE, /* 13 */
SIGALRM, /* 14 */
SIGTERM, /* 15 */
SIGUSR1, /* 16 */
SIGUSR2, /* 17 */
SIGCHLD, /* 18 */
0, /* 19 - SIGPWR */
SIGWINCH, /* 20 */
0, /* 21 */
SIGIO, /* 22 */
SIGSTOP, /* 23 */
SIGTSTP, /* 24 */
SIGCONT, /* 25 */
SIGTTIN, /* 26 */
SIGTTOU, /* 27 */
SIGVTALRM, /* 28 */
SIGPROF, /* 29 */
0, /* 30 */
0, /* 31 */
0 /* 32 */
};
void
ibcs2_to_bsd_sigset(iss, bss)
const ibcs2_sigset_t *iss;
sigset_t *bss;
{
int i, newsig;
sigemptyset(bss);
for (i = 1; i <= IBCS2_SIGTBLSZ; i++) {
if (ibcs2_sigismember(iss, i)) {
newsig = ibcs2_to_bsd_sig[_SIG_IDX(i)];
if (newsig)
sigaddset(bss, newsig);
}
}
}
static void
bsd_to_ibcs2_sigset(bss, iss)
const sigset_t *bss;
ibcs2_sigset_t *iss;
{
int i, newsig;
ibcs2_sigemptyset(iss);
for (i = 1; i <= IBCS2_SIGTBLSZ; i++) {
if (sigismember(bss, i)) {
newsig = bsd_to_ibcs2_sig[_SIG_IDX(i)];
if (newsig)
ibcs2_sigaddset(iss, newsig);
}
}
}
static void
ibcs2_to_bsd_sigaction(isa, bsa)
struct ibcs2_sigaction *isa;
struct sigaction *bsa;
{
bsa->sa_handler = isa->isa_handler;
ibcs2_to_bsd_sigset(&isa->isa_mask, &bsa->sa_mask);
bsa->sa_flags = 0; /* ??? SA_NODEFER */
if ((isa->isa_flags & IBCS2_SA_NOCLDSTOP) != 0)
bsa->sa_flags |= SA_NOCLDSTOP;
}
static void
bsd_to_ibcs2_sigaction(bsa, isa)
struct sigaction *bsa;
struct ibcs2_sigaction *isa;
{
isa->isa_handler = bsa->sa_handler;
bsd_to_ibcs2_sigset(&bsa->sa_mask, &isa->isa_mask);
isa->isa_flags = 0;
if ((bsa->sa_flags & SA_NOCLDSTOP) != 0)
isa->isa_flags |= IBCS2_SA_NOCLDSTOP;
}
int
ibcs2_sigaction(td, uap)
register struct thread *td;
struct ibcs2_sigaction_args *uap;
{
struct ibcs2_sigaction isa;
struct sigaction nbsa, obsa;
struct sigaction *nbsap;
int error;
if (uap->act != NULL) {
if ((error = copyin(uap->act, &isa, sizeof(isa))) != 0)
return (error);
ibcs2_to_bsd_sigaction(&isa, &nbsa);
nbsap = &nbsa;
} else
nbsap = NULL;
if (uap->sig <= 0 || uap->sig > IBCS2_NSIG)
return (EINVAL);
error = kern_sigaction(td, ibcs2_to_bsd_sig[_SIG_IDX(uap->sig)], &nbsa,
&obsa, 0);
if (error == 0 && uap->oact != NULL) {
bsd_to_ibcs2_sigaction(&obsa, &isa);
error = copyout(&isa, uap->oact, sizeof(isa));
}
return (error);
}
int
ibcs2_sigsys(td, uap)
register struct thread *td;
struct ibcs2_sigsys_args *uap;
{
struct proc *p = td->td_proc;
struct sigaction sa;
int signum = IBCS2_SIGNO(uap->sig);
int error;
if (signum <= 0 || signum > IBCS2_NSIG) {
if (IBCS2_SIGCALL(uap->sig) == IBCS2_SIGNAL_MASK ||
IBCS2_SIGCALL(uap->sig) == IBCS2_SIGSET_MASK)
td->td_retval[0] = (int)IBCS2_SIG_ERR;
return EINVAL;
}
signum = ibcs2_to_bsd_sig[_SIG_IDX(signum)];
switch (IBCS2_SIGCALL(uap->sig)) {
case IBCS2_SIGSET_MASK:
/*
* Check for SIG_HOLD action.
* Otherwise, perform signal() except with different sa_flags.
*/
if (uap->fp != IBCS2_SIG_HOLD) {
/* add sig to mask before exececuting signal handler */
sa.sa_flags = 0;
goto ibcs2_sigset;
}
/* else FALLTHROUGH to sighold */
case IBCS2_SIGHOLD_MASK:
{
sigset_t mask;
SIGEMPTYSET(mask);
SIGADDSET(mask, signum);
return (kern_sigprocmask(td, SIG_BLOCK, &mask, NULL,
0));
}
case IBCS2_SIGNAL_MASK:
{
struct sigaction osa;
/* do not automatically block signal */
sa.sa_flags = SA_NODEFER;
#ifdef SA_RESETHAND
if((signum != IBCS2_SIGILL) &&
(signum != IBCS2_SIGTRAP) &&
(signum != IBCS2_SIGPWR))
/* set to SIG_DFL before executing handler */
sa.sa_flags |= SA_RESETHAND;
#endif
ibcs2_sigset:
sa.sa_handler = uap->fp;
sigemptyset(&sa.sa_mask);
#if 0
if (signum != SIGALRM)
sa.sa_flags |= SA_RESTART;
#endif
error = kern_sigaction(td, signum, &sa, &osa, 0);
if (error != 0) {
DPRINTF(("signal: sigaction failed: %d\n",
error));
td->td_retval[0] = (int)IBCS2_SIG_ERR;
return (error);
}
td->td_retval[0] = (int)osa.sa_handler;
/* special sigset() check */
if(IBCS2_SIGCALL(uap->sig) == IBCS2_SIGSET_MASK) {
PROC_LOCK(p);
/* check to make sure signal is not blocked */
if(sigismember(&td->td_sigmask, signum)) {
/* return SIG_HOLD and unblock signal*/
td->td_retval[0] = (int)IBCS2_SIG_HOLD;
SIGDELSET(td->td_sigmask, signum);
signotify(td);
}
PROC_UNLOCK(p);
}
return 0;
}
case IBCS2_SIGRELSE_MASK:
{
sigset_t mask;
SIGEMPTYSET(mask);
SIGADDSET(mask, signum);
return (kern_sigprocmask(td, SIG_UNBLOCK, &mask, NULL,
0));
}
case IBCS2_SIGIGNORE_MASK:
{
sa.sa_handler = SIG_IGN;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
error = kern_sigaction(td, signum, &sa, NULL, 0);
if (error != 0)
DPRINTF(("sigignore: sigaction failed\n"));
return (error);
}
case IBCS2_SIGPAUSE_MASK:
{
sigset_t mask;
PROC_LOCK(p);
mask = td->td_sigmask;
PROC_UNLOCK(p);
SIGDELSET(mask, signum);
return kern_sigsuspend(td, mask);
}
default:
return ENOSYS;
}
}
int
ibcs2_sigprocmask(td, uap)
register struct thread *td;
struct ibcs2_sigprocmask_args *uap;
{
ibcs2_sigset_t iss;
sigset_t oss, nss;
sigset_t *nssp;
int error, how;
switch (uap->how) {
case IBCS2_SIG_BLOCK:
how = SIG_BLOCK;
break;
case IBCS2_SIG_UNBLOCK:
how = SIG_UNBLOCK;
break;
case IBCS2_SIG_SETMASK:
how = SIG_SETMASK;
break;
default:
return (EINVAL);
}
if (uap->set != NULL) {
if ((error = copyin(uap->set, &iss, sizeof(iss))) != 0)
return error;
ibcs2_to_bsd_sigset(&iss, &nss);
nssp = &nss;
} else
nssp = NULL;
error = kern_sigprocmask(td, how, nssp, &oss, 0);
if (error == 0 && uap->oset != NULL) {
bsd_to_ibcs2_sigset(&oss, &iss);
error = copyout(&iss, uap->oset, sizeof(iss));
}
return (error);
}
int
ibcs2_sigpending(td, uap)
register struct thread *td;
struct ibcs2_sigpending_args *uap;
{
struct proc *p = td->td_proc;
sigset_t bss;
ibcs2_sigset_t iss;
PROC_LOCK(p);
bss = td->td_siglist;
SIGSETOR(bss, p->p_siglist);
SIGSETAND(bss, td->td_sigmask);
PROC_UNLOCK(p);
bsd_to_ibcs2_sigset(&bss, &iss);
return copyout(&iss, uap->mask, sizeof(iss));
}
int
ibcs2_sigsuspend(td, uap)
register struct thread *td;
struct ibcs2_sigsuspend_args *uap;
{
ibcs2_sigset_t sss;
sigset_t bss;
int error;
if ((error = copyin(uap->mask, &sss, sizeof(sss))) != 0)
return error;
ibcs2_to_bsd_sigset(&sss, &bss);
return kern_sigsuspend(td, bss);
}
int
ibcs2_pause(td, uap)
register struct thread *td;
struct ibcs2_pause_args *uap;
{
sigset_t mask;
PROC_LOCK(td->td_proc);
mask = td->td_sigmask;
PROC_UNLOCK(td->td_proc);
return kern_sigsuspend(td, mask);
}
int
ibcs2_kill(td, uap)
register struct thread *td;
struct ibcs2_kill_args *uap;
{
struct kill_args ka;
if (uap->signo <= 0 || uap->signo > IBCS2_NSIG)
return (EINVAL);
ka.pid = uap->pid;
ka.signum = ibcs2_to_bsd_sig[_SIG_IDX(uap->signo)];
return kern_kill(td, &ka, 0);
}