linux/arch/alpha/kernel/signal.c

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/*
* linux/arch/alpha/kernel/signal.c
*
* Copyright (C) 1995 Linus Torvalds
*
* 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/stddef.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/bitops.h>
#include <linux/syscalls.h>
#include <linux/tracehook.h>
#include <asm/uaccess.h>
#include <asm/sigcontext.h>
#include <asm/ucontext.h>
#include "proto.h"
#define DEBUG_SIG 0
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
asmlinkage void ret_from_sys_call(void);
static void do_signal(struct pt_regs *, struct switch_stack *,
unsigned long, unsigned long);
/*
* The OSF/1 sigprocmask calling sequence is different from the
* C sigprocmask() sequence..
*/
SYSCALL_DEFINE2(osf_sigprocmask, int, how, unsigned long, newmask)
{
sigset_t oldmask;
sigset_t mask;
unsigned long res;
siginitset(&mask, newmask & _BLOCKABLE);
res = sigprocmask(how, &mask, &oldmask);
if (!res) {
force_successful_syscall_return();
res = oldmask.sig[0];
}
return res;
}
SYSCALL_DEFINE3(osf_sigaction, int, sig,
const struct osf_sigaction __user *, act,
struct osf_sigaction __user *, oact)
{
struct k_sigaction new_ka, old_ka;
int ret;
if (act) {
old_sigset_t mask;
if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
__get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
__get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
__get_user(mask, &act->sa_mask))
return -EFAULT;
siginitset(&new_ka.sa.sa_mask, mask);
new_ka.ka_restorer = NULL;
}
ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
if (!ret && oact) {
if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
__put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
__put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
return -EFAULT;
}
return ret;
}
SYSCALL_DEFINE5(rt_sigaction, int, sig, const struct sigaction __user *, act,
struct sigaction __user *, oact,
size_t, sigsetsize, void __user *, restorer)
{
struct k_sigaction new_ka, old_ka;
int ret;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
if (act) {
new_ka.ka_restorer = restorer;
if (copy_from_user(&new_ka.sa, act, sizeof(*act)))
return -EFAULT;
}
ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
if (!ret && oact) {
if (copy_to_user(oact, &old_ka.sa, sizeof(*oact)))
return -EFAULT;
}
return ret;
}
/*
* Atomically swap in the new signal mask, and wait for a signal.
*/
SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
{
sigset_t blocked;
siginitset(&blocked, mask);
return sigsuspend(&blocked);
}
asmlinkage int
sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
{
return do_sigaltstack(uss, uoss, rdusp());
}
/*
* Do a signal return; undo the signal stack.
*/
#if _NSIG_WORDS > 1
# error "Non SA_SIGINFO frame needs rearranging"
#endif
struct sigframe
{
struct sigcontext sc;
unsigned int retcode[3];
};
struct rt_sigframe
{
struct siginfo info;
struct ucontext uc;
unsigned int retcode[3];
};
/* If this changes, userland unwinders that Know Things about our signal
frame will break. Do not undertake lightly. It also implies an ABI
change wrt the size of siginfo_t, which may cause some pain. */
extern char compile_time_assert
[offsetof(struct rt_sigframe, uc.uc_mcontext) == 176 ? 1 : -1];
#define INSN_MOV_R30_R16 0x47fe0410
#define INSN_LDI_R0 0x201f0000
#define INSN_CALLSYS 0x00000083
static long
restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
struct switch_stack *sw)
{
unsigned long usp;
long i, err = __get_user(regs->pc, &sc->sc_pc);
current_thread_info()->restart_block.fn = do_no_restart_syscall;
sw->r26 = (unsigned long) ret_from_sys_call;
err |= __get_user(regs->r0, sc->sc_regs+0);
err |= __get_user(regs->r1, sc->sc_regs+1);
err |= __get_user(regs->r2, sc->sc_regs+2);
err |= __get_user(regs->r3, sc->sc_regs+3);
err |= __get_user(regs->r4, sc->sc_regs+4);
err |= __get_user(regs->r5, sc->sc_regs+5);
err |= __get_user(regs->r6, sc->sc_regs+6);
err |= __get_user(regs->r7, sc->sc_regs+7);
err |= __get_user(regs->r8, sc->sc_regs+8);
err |= __get_user(sw->r9, sc->sc_regs+9);
err |= __get_user(sw->r10, sc->sc_regs+10);
err |= __get_user(sw->r11, sc->sc_regs+11);
err |= __get_user(sw->r12, sc->sc_regs+12);
err |= __get_user(sw->r13, sc->sc_regs+13);
err |= __get_user(sw->r14, sc->sc_regs+14);
err |= __get_user(sw->r15, sc->sc_regs+15);
err |= __get_user(regs->r16, sc->sc_regs+16);
err |= __get_user(regs->r17, sc->sc_regs+17);
err |= __get_user(regs->r18, sc->sc_regs+18);
err |= __get_user(regs->r19, sc->sc_regs+19);
err |= __get_user(regs->r20, sc->sc_regs+20);
err |= __get_user(regs->r21, sc->sc_regs+21);
err |= __get_user(regs->r22, sc->sc_regs+22);
err |= __get_user(regs->r23, sc->sc_regs+23);
err |= __get_user(regs->r24, sc->sc_regs+24);
err |= __get_user(regs->r25, sc->sc_regs+25);
err |= __get_user(regs->r26, sc->sc_regs+26);
err |= __get_user(regs->r27, sc->sc_regs+27);
err |= __get_user(regs->r28, sc->sc_regs+28);
err |= __get_user(regs->gp, sc->sc_regs+29);
err |= __get_user(usp, sc->sc_regs+30);
wrusp(usp);
for (i = 0; i < 31; i++)
err |= __get_user(sw->fp[i], sc->sc_fpregs+i);
err |= __get_user(sw->fp[31], &sc->sc_fpcr);
return err;
}
/* Note that this syscall is also used by setcontext(3) to install
a given sigcontext. This because it's impossible to set *all*
registers and transfer control from userland. */
asmlinkage void
do_sigreturn(struct sigcontext __user *sc, struct pt_regs *regs,
struct switch_stack *sw)
{
sigset_t set;
/* Verify that it's a good sigcontext before using it */
if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
goto give_sigsegv;
if (__get_user(set.sig[0], &sc->sc_mask))
goto give_sigsegv;
sigdelsetmask(&set, ~_BLOCKABLE);
set_current_blocked(&set);
if (restore_sigcontext(sc, regs, sw))
goto give_sigsegv;
/* Send SIGTRAP if we're single-stepping: */
if (ptrace_cancel_bpt (current)) {
siginfo_t info;
info.si_signo = SIGTRAP;
info.si_errno = 0;
info.si_code = TRAP_BRKPT;
info.si_addr = (void __user *) regs->pc;
info.si_trapno = 0;
send_sig_info(SIGTRAP, &info, current);
}
return;
give_sigsegv:
force_sig(SIGSEGV, current);
}
asmlinkage void
do_rt_sigreturn(struct rt_sigframe __user *frame, struct pt_regs *regs,
struct switch_stack *sw)
{
sigset_t set;
/* Verify that it's a good ucontext_t before using it */
if (!access_ok(VERIFY_READ, &frame->uc, sizeof(frame->uc)))
goto give_sigsegv;
if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
goto give_sigsegv;
sigdelsetmask(&set, ~_BLOCKABLE);
set_current_blocked(&set);
if (restore_sigcontext(&frame->uc.uc_mcontext, regs, sw))
goto give_sigsegv;
/* Send SIGTRAP if we're single-stepping: */
if (ptrace_cancel_bpt (current)) {
siginfo_t info;
info.si_signo = SIGTRAP;
info.si_errno = 0;
info.si_code = TRAP_BRKPT;
info.si_addr = (void __user *) regs->pc;
info.si_trapno = 0;
send_sig_info(SIGTRAP, &info, current);
}
return;
give_sigsegv:
force_sig(SIGSEGV, current);
}
/*
* Set up a signal frame.
*/
static inline void __user *
get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
{
if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
sp = current->sas_ss_sp + current->sas_ss_size;
return (void __user *)((sp - frame_size) & -32ul);
}
static long
setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
struct switch_stack *sw, unsigned long mask, unsigned long sp)
{
long i, err = 0;
err |= __put_user(on_sig_stack((unsigned long)sc), &sc->sc_onstack);
err |= __put_user(mask, &sc->sc_mask);
err |= __put_user(regs->pc, &sc->sc_pc);
err |= __put_user(8, &sc->sc_ps);
err |= __put_user(regs->r0 , sc->sc_regs+0);
err |= __put_user(regs->r1 , sc->sc_regs+1);
err |= __put_user(regs->r2 , sc->sc_regs+2);
err |= __put_user(regs->r3 , sc->sc_regs+3);
err |= __put_user(regs->r4 , sc->sc_regs+4);
err |= __put_user(regs->r5 , sc->sc_regs+5);
err |= __put_user(regs->r6 , sc->sc_regs+6);
err |= __put_user(regs->r7 , sc->sc_regs+7);
err |= __put_user(regs->r8 , sc->sc_regs+8);
err |= __put_user(sw->r9 , sc->sc_regs+9);
err |= __put_user(sw->r10 , sc->sc_regs+10);
err |= __put_user(sw->r11 , sc->sc_regs+11);
err |= __put_user(sw->r12 , sc->sc_regs+12);
err |= __put_user(sw->r13 , sc->sc_regs+13);
err |= __put_user(sw->r14 , sc->sc_regs+14);
err |= __put_user(sw->r15 , sc->sc_regs+15);
err |= __put_user(regs->r16, sc->sc_regs+16);
err |= __put_user(regs->r17, sc->sc_regs+17);
err |= __put_user(regs->r18, sc->sc_regs+18);
err |= __put_user(regs->r19, sc->sc_regs+19);
err |= __put_user(regs->r20, sc->sc_regs+20);
err |= __put_user(regs->r21, sc->sc_regs+21);
err |= __put_user(regs->r22, sc->sc_regs+22);
err |= __put_user(regs->r23, sc->sc_regs+23);
err |= __put_user(regs->r24, sc->sc_regs+24);
err |= __put_user(regs->r25, sc->sc_regs+25);
err |= __put_user(regs->r26, sc->sc_regs+26);
err |= __put_user(regs->r27, sc->sc_regs+27);
err |= __put_user(regs->r28, sc->sc_regs+28);
err |= __put_user(regs->gp , sc->sc_regs+29);
err |= __put_user(sp, sc->sc_regs+30);
err |= __put_user(0, sc->sc_regs+31);
for (i = 0; i < 31; i++)
err |= __put_user(sw->fp[i], sc->sc_fpregs+i);
err |= __put_user(0, sc->sc_fpregs+31);
err |= __put_user(sw->fp[31], &sc->sc_fpcr);
err |= __put_user(regs->trap_a0, &sc->sc_traparg_a0);
err |= __put_user(regs->trap_a1, &sc->sc_traparg_a1);
err |= __put_user(regs->trap_a2, &sc->sc_traparg_a2);
return err;
}
static int
setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
struct pt_regs *regs, struct switch_stack * sw)
{
unsigned long oldsp, r26, err = 0;
struct sigframe __user *frame;
oldsp = rdusp();
frame = get_sigframe(ka, oldsp, sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
goto give_sigsegv;
err |= setup_sigcontext(&frame->sc, regs, sw, set->sig[0], oldsp);
if (err)
goto give_sigsegv;
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
if (ka->ka_restorer) {
r26 = (unsigned long) ka->ka_restorer;
} else {
err |= __put_user(INSN_MOV_R30_R16, frame->retcode+0);
err |= __put_user(INSN_LDI_R0+__NR_sigreturn, frame->retcode+1);
err |= __put_user(INSN_CALLSYS, frame->retcode+2);
imb();
r26 = (unsigned long) frame->retcode;
}
/* Check that everything was written properly. */
if (err)
goto give_sigsegv;
/* "Return" to the handler */
regs->r26 = r26;
regs->r27 = regs->pc = (unsigned long) ka->sa.sa_handler;
regs->r16 = sig; /* a0: signal number */
regs->r17 = 0; /* a1: exception code */
regs->r18 = (unsigned long) &frame->sc; /* a2: sigcontext pointer */
wrusp((unsigned long) frame);
#if DEBUG_SIG
printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
current->comm, current->pid, frame, regs->pc, regs->r26);
#endif
return 0;
give_sigsegv:
force_sigsegv(sig, current);
return -EFAULT;
}
static int
setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs *regs, struct switch_stack * sw)
{
unsigned long oldsp, r26, err = 0;
struct rt_sigframe __user *frame;
oldsp = rdusp();
frame = get_sigframe(ka, oldsp, sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
goto give_sigsegv;
err |= copy_siginfo_to_user(&frame->info, info);
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(0, &frame->uc.uc_link);
err |= __put_user(set->sig[0], &frame->uc.uc_osf_sigmask);
err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
err |= __put_user(sas_ss_flags(oldsp), &frame->uc.uc_stack.ss_flags);
err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, sw,
set->sig[0], oldsp);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (err)
goto give_sigsegv;
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
if (ka->ka_restorer) {
r26 = (unsigned long) ka->ka_restorer;
} else {
err |= __put_user(INSN_MOV_R30_R16, frame->retcode+0);
err |= __put_user(INSN_LDI_R0+__NR_rt_sigreturn,
frame->retcode+1);
err |= __put_user(INSN_CALLSYS, frame->retcode+2);
imb();
r26 = (unsigned long) frame->retcode;
}
if (err)
goto give_sigsegv;
/* "Return" to the handler */
regs->r26 = r26;
regs->r27 = regs->pc = (unsigned long) ka->sa.sa_handler;
regs->r16 = sig; /* a0: signal number */
regs->r17 = (unsigned long) &frame->info; /* a1: siginfo pointer */
regs->r18 = (unsigned long) &frame->uc; /* a2: ucontext pointer */
wrusp((unsigned long) frame);
#if DEBUG_SIG
printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
current->comm, current->pid, frame, regs->pc, regs->r26);
#endif
return 0;
give_sigsegv:
force_sigsegv(sig, current);
return -EFAULT;
}
/*
* OK, we're invoking a handler.
*/
static inline int
handle_signal(int sig, struct k_sigaction *ka, siginfo_t *info,
sigset_t *oldset, struct pt_regs * regs, struct switch_stack *sw)
{
int ret;
if (ka->sa.sa_flags & SA_SIGINFO)
ret = setup_rt_frame(sig, ka, info, oldset, regs, sw);
else
ret = setup_frame(sig, ka, oldset, regs, sw);
if (ret == 0)
block_sigmask(ka, sig);
return ret;
}
static inline void
syscall_restart(unsigned long r0, unsigned long r19,
struct pt_regs *regs, struct k_sigaction *ka)
{
switch (regs->r0) {
case ERESTARTSYS:
if (!(ka->sa.sa_flags & SA_RESTART)) {
case ERESTARTNOHAND:
regs->r0 = EINTR;
break;
}
/* fallthrough */
case ERESTARTNOINTR:
regs->r0 = r0; /* reset v0 and a3 and replay syscall */
regs->r19 = r19;
regs->pc -= 4;
break;
case ERESTART_RESTARTBLOCK:
regs->r0 = EINTR;
break;
}
}
/*
* Note that 'init' is a special process: it doesn't get signals it doesn't
* want to handle. Thus you cannot kill init even with a SIGKILL even by
* mistake.
*
* Note that we go through the signals twice: once to check the signals that
* the kernel can handle, and then we build all the user-level signal handling
* stack-frames in one go after that.
*
* "r0" and "r19" are the registers we need to restore for system call
* restart. "r0" is also used as an indicator whether we can restart at
* all (if we get here from anything but a syscall return, it will be 0)
*/
static void
do_signal(struct pt_regs * regs, struct switch_stack * sw,
unsigned long r0, unsigned long r19)
{
siginfo_t info;
int signr;
unsigned long single_stepping = ptrace_cancel_bpt(current);
struct k_sigaction ka;
sigset_t *oldset;
if (test_thread_flag(TIF_RESTORE_SIGMASK))
oldset = &current->saved_sigmask;
else
oldset = &current->blocked;
/* This lets the debugger run, ... */
signr = get_signal_to_deliver(&info, &ka, regs, NULL);
/* ... so re-check the single stepping. */
single_stepping |= ptrace_cancel_bpt(current);
if (signr > 0) {
/* Whee! Actually deliver the signal. */
if (r0)
syscall_restart(r0, r19, regs, &ka);
if (handle_signal(signr, &ka, &info, oldset, regs, sw) == 0) {
/* A signal was successfully delivered, and the
saved sigmask was stored on the signal frame,
and will be restored by sigreturn. So we can
simply clear the restore sigmask flag. */
if (test_thread_flag(TIF_RESTORE_SIGMASK))
clear_thread_flag(TIF_RESTORE_SIGMASK);
}
if (single_stepping)
ptrace_set_bpt(current); /* re-set bpt */
return;
}
if (r0) {
switch (regs->r0) {
case ERESTARTNOHAND:
case ERESTARTSYS:
case ERESTARTNOINTR:
/* Reset v0 and a3 and replay syscall. */
regs->r0 = r0;
regs->r19 = r19;
regs->pc -= 4;
break;
case ERESTART_RESTARTBLOCK:
/* Force v0 to the restart syscall and reply. */
regs->r0 = __NR_restart_syscall;
regs->pc -= 4;
break;
}
}
/* If there's no signal to deliver, we just restore the saved mask. */
if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
clear_thread_flag(TIF_RESTORE_SIGMASK);
sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
}
if (single_stepping)
ptrace_set_bpt(current); /* re-set breakpoint */
}
void
do_notify_resume(struct pt_regs *regs, struct switch_stack *sw,
unsigned long thread_info_flags,
unsigned long r0, unsigned long r19)
{
if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
do_signal(regs, sw, r0, r19);
if (thread_info_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
KEYS: Add a keyctl to install a process's session keyring on its parent [try #6] Add a keyctl to install a process's session keyring onto its parent. This replaces the parent's session keyring. Because the COW credential code does not permit one process to change another process's credentials directly, the change is deferred until userspace next starts executing again. Normally this will be after a wait*() syscall. To support this, three new security hooks have been provided: cred_alloc_blank() to allocate unset security creds, cred_transfer() to fill in the blank security creds and key_session_to_parent() - which asks the LSM if the process may replace its parent's session keyring. The replacement may only happen if the process has the same ownership details as its parent, and the process has LINK permission on the session keyring, and the session keyring is owned by the process, and the LSM permits it. Note that this requires alteration to each architecture's notify_resume path. This has been done for all arches barring blackfin, m68k* and xtensa, all of which need assembly alteration to support TIF_NOTIFY_RESUME. This allows the replacement to be performed at the point the parent process resumes userspace execution. This allows the userspace AFS pioctl emulation to fully emulate newpag() and the VIOCSETTOK and VIOCSETTOK2 pioctls, all of which require the ability to alter the parent process's PAG membership. However, since kAFS doesn't use PAGs per se, but rather dumps the keys into the session keyring, the session keyring of the parent must be replaced if, for example, VIOCSETTOK is passed the newpag flag. This can be tested with the following program: #include <stdio.h> #include <stdlib.h> #include <keyutils.h> #define KEYCTL_SESSION_TO_PARENT 18 #define OSERROR(X, S) do { if ((long)(X) == -1) { perror(S); exit(1); } } while(0) int main(int argc, char **argv) { key_serial_t keyring, key; long ret; keyring = keyctl_join_session_keyring(argv[1]); OSERROR(keyring, "keyctl_join_session_keyring"); key = add_key("user", "a", "b", 1, keyring); OSERROR(key, "add_key"); ret = keyctl(KEYCTL_SESSION_TO_PARENT); OSERROR(ret, "KEYCTL_SESSION_TO_PARENT"); return 0; } Compiled and linked with -lkeyutils, you should see something like: [dhowells@andromeda ~]$ keyctl show Session Keyring -3 --alswrv 4043 4043 keyring: _ses 355907932 --alswrv 4043 -1 \_ keyring: _uid.4043 [dhowells@andromeda ~]$ /tmp/newpag [dhowells@andromeda ~]$ keyctl show Session Keyring -3 --alswrv 4043 4043 keyring: _ses 1055658746 --alswrv 4043 4043 \_ user: a [dhowells@andromeda ~]$ /tmp/newpag hello [dhowells@andromeda ~]$ keyctl show Session Keyring -3 --alswrv 4043 4043 keyring: hello 340417692 --alswrv 4043 4043 \_ user: a Where the test program creates a new session keyring, sticks a user key named 'a' into it and then installs it on its parent. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-09-02 10:14:21 +02:00
if (current->replacement_session_keyring)
key_replace_session_keyring();
}
}