WSL2-Linux-Kernel/arch/frv/kernel/signal.c

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C
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/* signal.c: FRV specific bits of signal handling
*
* Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
* - Derived from arch/m68k/kernel/signal.c
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.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/personality.h>
#include <linux/freezer.h>
#include <linux/tracehook.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
#define DEBUG_SIG 0
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
struct fdpic_func_descriptor {
unsigned long text;
unsigned long GOT;
};
/*
* Atomically swap in the new signal mask, and wait for a signal.
*/
asmlinkage int sys_sigsuspend(int history0, int history1, old_sigset_t mask)
{
mask &= _BLOCKABLE;
spin_lock_irq(&current->sighand->siglock);
current->saved_sigmask = current->blocked;
siginitset(&current->blocked, mask);
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
current->state = TASK_INTERRUPTIBLE;
schedule();
set_thread_flag(TIF_RESTORE_SIGMASK);
return -ERESTARTNOHAND;
}
asmlinkage int sys_sigaction(int sig,
const struct old_sigaction __user *act,
struct old_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_restorer, &act->sa_restorer))
return -EFAULT;
__get_user(new_ka.sa.sa_flags, &act->sa_flags);
__get_user(mask, &act->sa_mask);
siginitset(&new_ka.sa.sa_mask, mask);
}
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_restorer, &oact->sa_restorer))
return -EFAULT;
__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
}
return ret;
}
asmlinkage
int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
{
return do_sigaltstack(uss, uoss, __frame->sp);
}
/*
* Do a signal return; undo the signal stack.
*/
struct sigframe
{
__sigrestore_t pretcode;
int sig;
struct sigcontext sc;
unsigned long extramask[_NSIG_WORDS-1];
uint32_t retcode[2];
};
struct rt_sigframe
{
__sigrestore_t pretcode;
int sig;
struct siginfo __user *pinfo;
void __user *puc;
struct siginfo info;
struct ucontext uc;
uint32_t retcode[2];
};
static int restore_sigcontext(struct sigcontext __user *sc, int *_gr8)
{
struct user_context *user = current->thread.user;
unsigned long tbr, psr;
tbr = user->i.tbr;
psr = user->i.psr;
if (copy_from_user(user, &sc->sc_context, sizeof(sc->sc_context)))
goto badframe;
user->i.tbr = tbr;
user->i.psr = psr;
restore_user_regs(user);
user->i.syscallno = -1; /* disable syscall checks */
*_gr8 = user->i.gr[8];
return 0;
badframe:
return 1;
}
asmlinkage int sys_sigreturn(void)
{
struct sigframe __user *frame = (struct sigframe __user *) __frame->sp;
sigset_t set;
int gr8;
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__get_user(set.sig[0], &frame->sc.sc_oldmask))
goto badframe;
if (_NSIG_WORDS > 1 &&
__copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask)))
goto badframe;
sigdelsetmask(&set, ~_BLOCKABLE);
spin_lock_irq(&current->sighand->siglock);
current->blocked = set;
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
if (restore_sigcontext(&frame->sc, &gr8))
goto badframe;
return gr8;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
asmlinkage int sys_rt_sigreturn(void)
{
struct rt_sigframe __user *frame = (struct rt_sigframe __user *) __frame->sp;
sigset_t set;
int gr8;
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
goto badframe;
sigdelsetmask(&set, ~_BLOCKABLE);
spin_lock_irq(&current->sighand->siglock);
current->blocked = set;
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
if (restore_sigcontext(&frame->uc.uc_mcontext, &gr8))
goto badframe;
if (do_sigaltstack(&frame->uc.uc_stack, NULL, __frame->sp) == -EFAULT)
goto badframe;
return gr8;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
/*
* Set up a signal frame
*/
static int setup_sigcontext(struct sigcontext __user *sc, unsigned long mask)
{
save_user_regs(current->thread.user);
if (copy_to_user(&sc->sc_context, current->thread.user, sizeof(sc->sc_context)) != 0)
goto badframe;
/* non-iBCS2 extensions.. */
if (__put_user(mask, &sc->sc_oldmask) < 0)
goto badframe;
return 0;
badframe:
return 1;
}
/*****************************************************************************/
/*
* Determine which stack to use..
*/
static inline void __user *get_sigframe(struct k_sigaction *ka,
size_t frame_size)
{
unsigned long sp;
/* Default to using normal stack */
sp = __frame->sp;
/* This is the X/Open sanctioned signal stack switching. */
if (ka->sa.sa_flags & SA_ONSTACK) {
if (! sas_ss_flags(sp))
sp = current->sas_ss_sp + current->sas_ss_size;
}
return (void __user *) ((sp - frame_size) & ~7UL);
} /* end get_sigframe() */
/*****************************************************************************/
/*
*
*/
static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set)
{
struct sigframe __user *frame;
int rsig;
frame = get_sigframe(ka, sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
goto give_sigsegv;
rsig = sig;
if (sig < 32 &&
__current_thread_info->exec_domain &&
__current_thread_info->exec_domain->signal_invmap)
rsig = __current_thread_info->exec_domain->signal_invmap[sig];
if (__put_user(rsig, &frame->sig) < 0)
goto give_sigsegv;
if (setup_sigcontext(&frame->sc, set->sig[0]))
goto give_sigsegv;
if (_NSIG_WORDS > 1) {
if (__copy_to_user(frame->extramask, &set->sig[1],
sizeof(frame->extramask)))
goto give_sigsegv;
}
/* Set up to return from userspace. If provided, use a stub
* already in userspace. */
if (ka->sa.sa_flags & SA_RESTORER) {
if (__put_user(ka->sa.sa_restorer, &frame->pretcode) < 0)
goto give_sigsegv;
}
else {
/* Set up the following code on the stack:
* setlos #__NR_sigreturn,gr7
* tira gr0,0
*/
if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
__put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) ||
__put_user(0xc0700000, &frame->retcode[1]))
goto give_sigsegv;
flush_icache_range((unsigned long) frame->retcode,
(unsigned long) (frame->retcode + 2));
}
/* set up registers for signal handler */
__frame->sp = (unsigned long) frame;
__frame->lr = (unsigned long) &frame->retcode;
__frame->gr8 = sig;
if (current->personality & FDPIC_FUNCPTRS) {
struct fdpic_func_descriptor __user *funcptr =
(struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
__get_user(__frame->pc, &funcptr->text);
__get_user(__frame->gr15, &funcptr->GOT);
} else {
__frame->pc = (unsigned long) ka->sa.sa_handler;
__frame->gr15 = 0;
}
set_fs(USER_DS);
/* the tracer may want to single-step inside the handler */
if (test_thread_flag(TIF_SINGLESTEP))
ptrace_notify(SIGTRAP);
#if DEBUG_SIG
printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
sig, current->comm, current->pid, frame, __frame->pc,
frame->pretcode);
#endif
return 0;
give_sigsegv:
force_sig(SIGSEGV, current);
return -EFAULT;
} /* end setup_frame() */
/*****************************************************************************/
/*
*
*/
static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set)
{
struct rt_sigframe __user *frame;
int rsig;
frame = get_sigframe(ka, sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
goto give_sigsegv;
rsig = sig;
if (sig < 32 &&
__current_thread_info->exec_domain &&
__current_thread_info->exec_domain->signal_invmap)
rsig = __current_thread_info->exec_domain->signal_invmap[sig];
if (__put_user(rsig, &frame->sig) ||
__put_user(&frame->info, &frame->pinfo) ||
__put_user(&frame->uc, &frame->puc))
goto give_sigsegv;
if (copy_siginfo_to_user(&frame->info, info))
goto give_sigsegv;
/* Create the ucontext. */
if (__put_user(0, &frame->uc.uc_flags) ||
__put_user(NULL, &frame->uc.uc_link) ||
__put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
__put_user(sas_ss_flags(__frame->sp), &frame->uc.uc_stack.ss_flags) ||
__put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size))
goto give_sigsegv;
if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0]))
goto give_sigsegv;
if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
goto give_sigsegv;
/* Set up to return from userspace. If provided, use a stub
* already in userspace. */
if (ka->sa.sa_flags & SA_RESTORER) {
if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
goto give_sigsegv;
}
else {
/* Set up the following code on the stack:
* setlos #__NR_sigreturn,gr7
* tira gr0,0
*/
if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
__put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) ||
__put_user(0xc0700000, &frame->retcode[1]))
goto give_sigsegv;
flush_icache_range((unsigned long) frame->retcode,
(unsigned long) (frame->retcode + 2));
}
/* Set up registers for signal handler */
__frame->sp = (unsigned long) frame;
__frame->lr = (unsigned long) &frame->retcode;
__frame->gr8 = sig;
__frame->gr9 = (unsigned long) &frame->info;
if (current->personality & FDPIC_FUNCPTRS) {
struct fdpic_func_descriptor __user *funcptr =
(struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
__get_user(__frame->pc, &funcptr->text);
__get_user(__frame->gr15, &funcptr->GOT);
} else {
__frame->pc = (unsigned long) ka->sa.sa_handler;
__frame->gr15 = 0;
}
set_fs(USER_DS);
/* the tracer may want to single-step inside the handler */
if (test_thread_flag(TIF_SINGLESTEP))
ptrace_notify(SIGTRAP);
#if DEBUG_SIG
printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
sig, current->comm, current->pid, frame, __frame->pc,
frame->pretcode);
#endif
return 0;
give_sigsegv:
force_sig(SIGSEGV, current);
return -EFAULT;
} /* end setup_rt_frame() */
/*****************************************************************************/
/*
* OK, we're invoking a handler
*/
static int handle_signal(unsigned long sig, siginfo_t *info,
struct k_sigaction *ka, sigset_t *oldset)
{
int ret;
/* Are we from a system call? */
if (in_syscall(__frame)) {
/* If so, check system call restarting.. */
switch (__frame->gr8) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
__frame->gr8 = -EINTR;
break;
case -ERESTARTSYS:
if (!(ka->sa.sa_flags & SA_RESTART)) {
__frame->gr8 = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
__frame->gr8 = __frame->orig_gr8;
__frame->pc -= 4;
}
}
/* Set up the stack frame */
if (ka->sa.sa_flags & SA_SIGINFO)
ret = setup_rt_frame(sig, ka, info, oldset);
else
ret = setup_frame(sig, ka, oldset);
if (ret == 0) {
spin_lock_irq(&current->sighand->siglock);
sigorsets(&current->blocked, &current->blocked,
&ka->sa.sa_mask);
if (!(ka->sa.sa_flags & SA_NODEFER))
sigaddset(&current->blocked, sig);
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
}
return ret;
} /* end handle_signal() */
/*****************************************************************************/
/*
* 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.
*/
static void do_signal(void)
{
struct k_sigaction ka;
siginfo_t info;
sigset_t *oldset;
int signr;
/*
* We want the common case to go fast, which
* is why we may in certain cases get here from
* kernel mode. Just return without doing anything
* if so.
*/
if (!user_mode(__frame))
return;
if (try_to_freeze())
goto no_signal;
if (test_thread_flag(TIF_RESTORE_SIGMASK))
oldset = &current->saved_sigmask;
else
oldset = &current->blocked;
signr = get_signal_to_deliver(&info, &ka, __frame, NULL);
if (signr > 0) {
if (handle_signal(signr, &info, &ka, oldset) == 0) {
/* a signal was successfully delivered; the saved
* sigmask will have been stored in the signal frame,
* and will be restored by sigreturn, so we can simply
* clear the TIF_RESTORE_SIGMASK flag */
if (test_thread_flag(TIF_RESTORE_SIGMASK))
clear_thread_flag(TIF_RESTORE_SIGMASK);
tracehook_signal_handler(signr, &info, &ka, __frame,
test_thread_flag(TIF_SINGLESTEP));
}
return;
}
no_signal:
/* Did we come from a system call? */
if (__frame->syscallno != -1) {
/* Restart the system call - no handlers present */
switch (__frame->gr8) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
__frame->gr8 = __frame->orig_gr8;
__frame->pc -= 4;
break;
case -ERESTART_RESTARTBLOCK:
__frame->gr8 = __NR_restart_syscall;
__frame->pc -= 4;
break;
}
}
/* if there's no signal to deliver, we just put the saved sigmask
* back */
if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
clear_thread_flag(TIF_RESTORE_SIGMASK);
sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
}
} /* end do_signal() */
/*****************************************************************************/
/*
* notification of userspace execution resumption
* - triggered by the TIF_WORK_MASK flags
*/
asmlinkage void do_notify_resume(__u32 thread_info_flags)
{
/* pending single-step? */
if (thread_info_flags & _TIF_SINGLESTEP)
clear_thread_flag(TIF_SINGLESTEP);
/* deal with pending signal delivery */
if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
do_signal();
/* deal with notification on about to resume userspace execution */
if (thread_info_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(__frame);
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 12:14:21 +04:00
if (current->replacement_session_keyring)
key_replace_session_keyring();
}
} /* end do_notify_resume() */