freebsd-dev/sys/compat/svr4/svr4_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

580 lines
13 KiB
C

/*-
* Copyright (c) 1998 Mark Newton
* Copyright (c) 1994 Christos Zoulas
* 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/filedesc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/signal.h>
#include <sys/signalvar.h>
#include <sys/syscallsubr.h>
#include <sys/sysproto.h>
#include <machine/cpu.h>
#include <compat/svr4/svr4.h>
#include <compat/svr4/svr4_types.h>
#include <compat/svr4/svr4_signal.h>
#include <compat/svr4/svr4_proto.h>
#include <compat/svr4/svr4_util.h>
#include <compat/svr4/svr4_ucontext.h>
#define svr4_sigmask(n) (1 << (((n) - 1) & 31))
#define svr4_sigword(n) (((n) - 1) >> 5)
#define svr4_sigemptyset(s) memset((s), 0, sizeof(*(s)))
#define svr4_sigismember(s, n) ((s)->bits[svr4_sigword(n)] & svr4_sigmask(n))
#define svr4_sigaddset(s, n) ((s)->bits[svr4_sigword(n)] |= svr4_sigmask(n))
void svr4_to_bsd_sigaction(const struct svr4_sigaction *, struct sigaction *);
void bsd_to_svr4_sigaction(const struct sigaction *, struct svr4_sigaction *);
void svr4_sigfillset(svr4_sigset_t *);
int bsd_to_svr4_sig[SVR4_SIGTBLSZ] = {
SVR4_SIGHUP,
SVR4_SIGINT,
SVR4_SIGQUIT,
SVR4_SIGILL,
SVR4_SIGTRAP,
SVR4_SIGABRT,
SVR4_SIGEMT,
SVR4_SIGFPE,
SVR4_SIGKILL,
SVR4_SIGBUS,
SVR4_SIGSEGV,
SVR4_SIGSYS,
SVR4_SIGPIPE,
SVR4_SIGALRM,
SVR4_SIGTERM,
SVR4_SIGURG,
SVR4_SIGSTOP,
SVR4_SIGTSTP,
SVR4_SIGCONT,
SVR4_SIGCHLD,
SVR4_SIGTTIN,
SVR4_SIGTTOU,
SVR4_SIGIO,
SVR4_SIGXCPU,
SVR4_SIGXFSZ,
SVR4_SIGVTALRM,
SVR4_SIGPROF,
SVR4_SIGWINCH,
0, /* SIGINFO */
SVR4_SIGUSR1,
SVR4_SIGUSR2,
};
int svr4_to_bsd_sig[SVR4_SIGTBLSZ] = {
SIGHUP,
SIGINT,
SIGQUIT,
SIGILL,
SIGTRAP,
SIGABRT,
SIGEMT,
SIGFPE,
SIGKILL,
SIGBUS,
SIGSEGV,
SIGSYS,
SIGPIPE,
SIGALRM,
SIGTERM,
SIGUSR1,
SIGUSR2,
SIGCHLD,
0, /* XXX NetBSD uses SIGPWR here, but we don't seem to have one */
SIGWINCH,
SIGURG,
SIGIO,
SIGSTOP,
SIGTSTP,
SIGCONT,
SIGTTIN,
SIGTTOU,
SIGVTALRM,
SIGPROF,
SIGXCPU,
SIGXFSZ,
};
void
svr4_sigfillset(s)
svr4_sigset_t *s;
{
int i;
svr4_sigemptyset(s);
for (i = 0; i < SVR4_NSIG; i++)
if (svr4_to_bsd_sig[i] != 0)
svr4_sigaddset(s, i);
}
void
svr4_to_bsd_sigset(sss, bss)
const svr4_sigset_t *sss;
sigset_t *bss;
{
int i, newsig;
SIGEMPTYSET(*bss);
for (i = 0; i < SVR4_NSIG; i++)
if (svr4_sigismember(sss, i + 1)) {
newsig = svr4_to_bsd_sig[i];
if (newsig)
SIGADDSET(*bss, newsig);
}
}
void
bsd_to_svr4_sigset(bss, sss)
const sigset_t *bss;
svr4_sigset_t *sss;
{
int i, newsig;
svr4_sigemptyset(sss);
sss->bits[0] = bss->__bits[0] & ~((1U << SVR4_SIGTBLSZ) - 1);
sss->bits[1] = bss->__bits[1];
sss->bits[2] = bss->__bits[2];
sss->bits[3] = bss->__bits[3];
for (i = 1; i <= SVR4_SIGTBLSZ; i++) {
if (SIGISMEMBER(*bss, i)) {
newsig = bsd_to_svr4_sig[_SIG_IDX(i)];
if (newsig)
svr4_sigaddset(sss, newsig);
}
}
}
/*
* XXX: Only a subset of the flags is currently implemented.
*/
void
svr4_to_bsd_sigaction(ssa, bsa)
const struct svr4_sigaction *ssa;
struct sigaction *bsa;
{
bsa->sa_handler = (sig_t) ssa->ssa_handler;
svr4_to_bsd_sigset(&ssa->ssa_mask, &bsa->sa_mask);
bsa->sa_flags = 0;
if ((ssa->ssa_flags & SVR4_SA_ONSTACK) != 0)
bsa->sa_flags |= SA_ONSTACK;
if ((ssa->ssa_flags & SVR4_SA_RESETHAND) != 0)
bsa->sa_flags |= SA_RESETHAND;
if ((ssa->ssa_flags & SVR4_SA_RESTART) != 0)
bsa->sa_flags |= SA_RESTART;
if ((ssa->ssa_flags & SVR4_SA_SIGINFO) != 0)
DPRINTF(("svr4_to_bsd_sigaction: SA_SIGINFO ignored\n"));
if ((ssa->ssa_flags & SVR4_SA_NOCLDSTOP) != 0)
bsa->sa_flags |= SA_NOCLDSTOP;
if ((ssa->ssa_flags & SVR4_SA_NODEFER) != 0)
bsa->sa_flags |= SA_NODEFER;
if ((ssa->ssa_flags & SVR4_SA_NOCLDWAIT) != 0)
bsa->sa_flags |= SA_NOCLDWAIT;
if ((ssa->ssa_flags & ~SVR4_SA_ALLBITS) != 0)
DPRINTF(("svr4_to_bsd_sigaction: extra bits ignored\n"));
}
void
bsd_to_svr4_sigaction(bsa, ssa)
const struct sigaction *bsa;
struct svr4_sigaction *ssa;
{
ssa->ssa_handler = (svr4_sig_t) bsa->sa_handler;
bsd_to_svr4_sigset(&bsa->sa_mask, &ssa->ssa_mask);
ssa->ssa_flags = 0;
if ((bsa->sa_flags & SA_ONSTACK) != 0)
ssa->ssa_flags |= SVR4_SA_ONSTACK;
if ((bsa->sa_flags & SA_RESETHAND) != 0)
ssa->ssa_flags |= SVR4_SA_RESETHAND;
if ((bsa->sa_flags & SA_RESTART) != 0)
ssa->ssa_flags |= SVR4_SA_RESTART;
if ((bsa->sa_flags & SA_NODEFER) != 0)
ssa->ssa_flags |= SVR4_SA_NODEFER;
if ((bsa->sa_flags & SA_NOCLDSTOP) != 0)
ssa->ssa_flags |= SVR4_SA_NOCLDSTOP;
}
void
svr4_to_bsd_sigaltstack(sss, bss)
const struct svr4_sigaltstack *sss;
struct sigaltstack *bss;
{
bss->ss_sp = sss->ss_sp;
bss->ss_size = sss->ss_size;
bss->ss_flags = 0;
if ((sss->ss_flags & SVR4_SS_DISABLE) != 0)
bss->ss_flags |= SS_DISABLE;
if ((sss->ss_flags & SVR4_SS_ONSTACK) != 0)
bss->ss_flags |= SS_ONSTACK;
if ((sss->ss_flags & ~SVR4_SS_ALLBITS) != 0)
/*XXX*/ uprintf("svr4_to_bsd_sigaltstack: extra bits ignored\n");
}
void
bsd_to_svr4_sigaltstack(bss, sss)
const struct sigaltstack *bss;
struct svr4_sigaltstack *sss;
{
sss->ss_sp = bss->ss_sp;
sss->ss_size = bss->ss_size;
sss->ss_flags = 0;
if ((bss->ss_flags & SS_DISABLE) != 0)
sss->ss_flags |= SVR4_SS_DISABLE;
if ((bss->ss_flags & SS_ONSTACK) != 0)
sss->ss_flags |= SVR4_SS_ONSTACK;
}
int
svr4_sys_sigaction(td, uap)
register struct thread *td;
struct svr4_sys_sigaction_args *uap;
{
struct svr4_sigaction isa;
struct sigaction nbsa, obsa;
struct sigaction *nbsap;
int error;
if (uap->signum < 0 || uap->signum >= SVR4_NSIG)
return (EINVAL);
DPRINTF(("@@@ svr4_sys_sigaction(%d, %d, %d)\n", td->td_proc->p_pid,
uap->signum,
SVR4_SVR42BSD_SIG(uap->signum)));
if (uap->nsa != NULL) {
if ((error = copyin(uap->nsa, &isa, sizeof(isa))) != 0)
return (error);
svr4_to_bsd_sigaction(&isa, &nbsa);
nbsap = &nbsa;
} else
nbsap = NULL;
#if defined(DEBUG_SVR4)
{
int i;
for (i = 0; i < 4; i++)
DPRINTF(("\tssa_mask[%d] = %lx\n", i,
isa.ssa_mask.bits[i]));
DPRINTF(("\tssa_handler = %p\n", isa.ssa_handler));
}
#endif
error = kern_sigaction(td, SVR4_SVR42BSD_SIG(uap->signum), nbsap, &obsa,
0);
if (error == 0 && uap->osa != NULL) {
bsd_to_svr4_sigaction(&obsa, &isa);
error = copyout(&isa, uap->osa, sizeof(isa));
}
return (error);
}
int
svr4_sys_sigaltstack(td, uap)
register struct thread *td;
struct svr4_sys_sigaltstack_args *uap;
{
struct svr4_sigaltstack sss;
struct sigaltstack nbss, obss, *nbssp;
int error;
if (uap->nss != NULL) {
if ((error = copyin(uap->nss, &sss, sizeof(sss))) != 0)
return (error);
svr4_to_bsd_sigaltstack(&sss, &nbss);
nbssp = &nbss;
} else
nbssp = NULL;
error = kern_sigaltstack(td, nbssp, &obss);
if (error == 0 && uap->oss != NULL) {
bsd_to_svr4_sigaltstack(&obss, &sss);
error = copyout(&sss, uap->oss, sizeof(sss));
}
return (error);
}
/*
* Stolen from the ibcs2 one
*/
int
svr4_sys_signal(td, uap)
register struct thread *td;
struct svr4_sys_signal_args *uap;
{
struct proc *p;
int signum;
int error;
p = td->td_proc;
DPRINTF(("@@@ svr4_sys_signal(%d)\n", p->p_pid));
signum = SVR4_SIGNO(uap->signum);
if (signum < 0 || signum >= SVR4_NSIG) {
if (SVR4_SIGCALL(uap->signum) == SVR4_SIGNAL_MASK ||
SVR4_SIGCALL(uap->signum) == SVR4_SIGDEFER_MASK)
td->td_retval[0] = (int)SVR4_SIG_ERR;
return (EINVAL);
}
signum = SVR4_SVR42BSD_SIG(signum);
switch (SVR4_SIGCALL(uap->signum)) {
case SVR4_SIGDEFER_MASK:
if (uap->handler == SVR4_SIG_HOLD)
goto sighold;
/* FALLTHROUGH */
case SVR4_SIGNAL_MASK:
{
struct sigaction nbsa, obsa;
nbsa.sa_handler = (sig_t) uap->handler;
SIGEMPTYSET(nbsa.sa_mask);
nbsa.sa_flags = 0;
if (signum != SIGALRM)
nbsa.sa_flags = SA_RESTART;
error = kern_sigaction(td, signum, &nbsa, &obsa, 0);
if (error != 0) {
DPRINTF(("signal: sigaction failed: %d\n",
error));
td->td_retval[0] = (int)SVR4_SIG_ERR;
return (error);
}
td->td_retval[0] = (int)obsa.sa_handler;
return (0);
}
case SVR4_SIGHOLD_MASK:
sighold:
{
sigset_t set;
SIGEMPTYSET(set);
SIGADDSET(set, signum);
return (kern_sigprocmask(td, SIG_BLOCK, &set, NULL, 0));
}
case SVR4_SIGRELSE_MASK:
{
sigset_t set;
SIGEMPTYSET(set);
SIGADDSET(set, signum);
return (kern_sigprocmask(td, SIG_UNBLOCK, &set, NULL,
0));
}
case SVR4_SIGIGNORE_MASK:
{
struct sigaction sa;
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 SVR4_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
svr4_sys_sigprocmask(td, uap)
struct thread *td;
struct svr4_sys_sigprocmask_args *uap;
{
svr4_sigset_t sss;
sigset_t oss, nss;
sigset_t *nssp;
int error;
if (uap->set != NULL) {
if ((error = copyin(uap->set, &sss, sizeof(sss))) != 0)
return error;
svr4_to_bsd_sigset(&sss, &nss);
nssp = &nss;
} else
nssp = NULL;
/* SVR/4 sigprocmask flag values are the same as the FreeBSD values. */
error = kern_sigprocmask(td, uap->how, nssp, &oss, 0);
if (error == 0 && uap->oset != NULL) {
bsd_to_svr4_sigset(&oss, &sss);
error = copyout(&sss, uap->oset, sizeof(sss));
}
return (error);
}
int
svr4_sys_sigpending(td, uap)
struct thread *td;
struct svr4_sys_sigpending_args *uap;
{
struct proc *p;
sigset_t bss;
svr4_sigset_t sss;
p = td->td_proc;
DPRINTF(("@@@ svr4_sys_sigpending(%d)\n", p->p_pid));
switch (uap->what) {
case 1: /* sigpending */
if (uap->mask == NULL)
return 0;
PROC_LOCK(p);
bss = p->p_siglist;
SIGSETOR(bss, td->td_siglist);
SIGSETAND(bss, td->td_sigmask);
PROC_UNLOCK(p);
bsd_to_svr4_sigset(&bss, &sss);
break;
case 2: /* sigfillset */
svr4_sigfillset(&sss);
#if defined(DEBUG_SVR4)
{
int i;
for (i = 0; i < 4; i++)
DPRINTF(("new sigset[%d] = %lx\n", i, (long)sss.bits[i]));
}
#endif
break;
default:
return EINVAL;
}
return copyout(&sss, uap->mask, sizeof(sss));
}
int
svr4_sys_sigsuspend(td, uap)
register struct thread *td;
struct svr4_sys_sigsuspend_args *uap;
{
svr4_sigset_t sss;
sigset_t bss;
int error;
if ((error = copyin(uap->ss, &sss, sizeof(sss))) != 0)
return error;
svr4_to_bsd_sigset(&sss, &bss);
return kern_sigsuspend(td, bss);
}
int
svr4_sys_kill(td, uap)
register struct thread *td;
struct svr4_sys_kill_args *uap;
{
struct kill_args ka;
if (uap->signum < 0 || uap->signum >= SVR4_NSIG)
return (EINVAL);
ka.pid = uap->pid;
ka.signum = SVR4_SVR42BSD_SIG(uap->signum);
return kern_kill(td, &ka, 0);
}
int
svr4_sys_context(td, uap)
register struct thread *td;
struct svr4_sys_context_args *uap;
{
struct svr4_ucontext uc;
int error, onstack;
switch (uap->func) {
case 0:
DPRINTF(("getcontext(%p)\n", uap->uc));
PROC_LOCK(td->td_proc);
onstack = sigonstack(cpu_getstack(td));
PROC_UNLOCK(td->td_proc);
svr4_getcontext(td, &uc, &td->td_sigmask, onstack);
return copyout(&uc, uap->uc, sizeof(uc));
case 1:
DPRINTF(("setcontext(%p)\n", uap->uc));
if ((error = copyin(uap->uc, &uc, sizeof(uc))) != 0)
return error;
DPRINTF(("uc_flags = %lx\n", uc.uc_flags));
#if defined(DEBUG_SVR4)
{
int i;
for (i = 0; i < 4; i++)
DPRINTF(("uc_sigmask[%d] = %lx\n", i,
uc.uc_sigmask.bits[i]));
}
#endif
return svr4_setcontext(td, &uc);
default:
DPRINTF(("context(%d, %p)\n", uap->func,
uap->uc));
return ENOSYS;
}
return 0;
}
int
svr4_sys_pause(td, uap)
register struct thread *td;
struct svr4_sys_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);
}