![Heiko Carstens](/assets/img/avatar_default.png)
Consider return value of __put_user() when setting up a signal frame instead of ignoring it. Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
524 lines
14 KiB
C
524 lines
14 KiB
C
/*
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* arch/s390/kernel/signal.c
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*
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* Copyright (C) IBM Corp. 1999,2006
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* Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
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*
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* Based on Intel version
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
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*/
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#include <linux/config.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/smp_lock.h>
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#include <linux/kernel.h>
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#include <linux/signal.h>
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#include <linux/errno.h>
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#include <linux/wait.h>
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#include <linux/ptrace.h>
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#include <linux/unistd.h>
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#include <linux/stddef.h>
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#include <linux/tty.h>
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#include <linux/personality.h>
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#include <linux/binfmts.h>
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#include <asm/ucontext.h>
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#include <asm/uaccess.h>
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#include <asm/lowcore.h>
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#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
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typedef struct
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{
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__u8 callee_used_stack[__SIGNAL_FRAMESIZE];
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struct sigcontext sc;
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_sigregs sregs;
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int signo;
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__u8 retcode[S390_SYSCALL_SIZE];
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} sigframe;
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typedef struct
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{
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__u8 callee_used_stack[__SIGNAL_FRAMESIZE];
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__u8 retcode[S390_SYSCALL_SIZE];
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struct siginfo info;
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struct ucontext uc;
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} rt_sigframe;
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/*
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* Atomically swap in the new signal mask, and wait for a signal.
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*/
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asmlinkage int
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sys_sigsuspend(int history0, int history1, old_sigset_t mask)
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{
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mask &= _BLOCKABLE;
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spin_lock_irq(¤t->sighand->siglock);
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current->saved_sigmask = current->blocked;
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siginitset(¤t->blocked, mask);
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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current->state = TASK_INTERRUPTIBLE;
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schedule();
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set_thread_flag(TIF_RESTORE_SIGMASK);
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return -ERESTARTNOHAND;
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}
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asmlinkage long
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sys_sigaction(int sig, const struct old_sigaction __user *act,
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struct old_sigaction __user *oact)
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{
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struct k_sigaction new_ka, old_ka;
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int ret;
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if (act) {
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old_sigset_t mask;
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if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
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__get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
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__get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
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return -EFAULT;
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__get_user(new_ka.sa.sa_flags, &act->sa_flags);
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__get_user(mask, &act->sa_mask);
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siginitset(&new_ka.sa.sa_mask, mask);
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}
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ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
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if (!ret && oact) {
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if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
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__put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
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__put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
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return -EFAULT;
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__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
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__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
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}
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return ret;
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}
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asmlinkage long
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sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
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struct pt_regs *regs)
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{
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return do_sigaltstack(uss, uoss, regs->gprs[15]);
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}
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/* Returns non-zero on fault. */
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static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
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{
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unsigned long old_mask = regs->psw.mask;
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int err;
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save_access_regs(current->thread.acrs);
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/* Copy a 'clean' PSW mask to the user to avoid leaking
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information about whether PER is currently on. */
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regs->psw.mask = PSW_MASK_MERGE(PSW_USER_BITS, regs->psw.mask);
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err = __copy_to_user(&sregs->regs.psw, ®s->psw,
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sizeof(sregs->regs.psw)+sizeof(sregs->regs.gprs));
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regs->psw.mask = old_mask;
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if (err != 0)
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return err;
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err = __copy_to_user(&sregs->regs.acrs, current->thread.acrs,
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sizeof(sregs->regs.acrs));
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if (err != 0)
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return err;
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/*
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* We have to store the fp registers to current->thread.fp_regs
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* to merge them with the emulated registers.
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*/
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save_fp_regs(¤t->thread.fp_regs);
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return __copy_to_user(&sregs->fpregs, ¤t->thread.fp_regs,
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sizeof(s390_fp_regs));
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}
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/* Returns positive number on error */
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static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
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{
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unsigned long old_mask = regs->psw.mask;
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int err;
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/* Alwys make any pending restarted system call return -EINTR */
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current_thread_info()->restart_block.fn = do_no_restart_syscall;
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err = __copy_from_user(®s->psw, &sregs->regs.psw,
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sizeof(sregs->regs.psw)+sizeof(sregs->regs.gprs));
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regs->psw.mask = PSW_MASK_MERGE(old_mask, regs->psw.mask);
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regs->psw.addr |= PSW_ADDR_AMODE;
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if (err)
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return err;
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err = __copy_from_user(¤t->thread.acrs, &sregs->regs.acrs,
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sizeof(sregs->regs.acrs));
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if (err)
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return err;
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restore_access_regs(current->thread.acrs);
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err = __copy_from_user(¤t->thread.fp_regs, &sregs->fpregs,
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sizeof(s390_fp_regs));
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current->thread.fp_regs.fpc &= FPC_VALID_MASK;
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if (err)
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return err;
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restore_fp_regs(¤t->thread.fp_regs);
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regs->trap = -1; /* disable syscall checks */
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return 0;
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}
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asmlinkage long sys_sigreturn(struct pt_regs *regs)
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{
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sigframe __user *frame = (sigframe __user *)regs->gprs[15];
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sigset_t set;
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if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
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goto badframe;
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if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
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goto badframe;
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sigdelsetmask(&set, ~_BLOCKABLE);
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spin_lock_irq(¤t->sighand->siglock);
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current->blocked = set;
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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if (restore_sigregs(regs, &frame->sregs))
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goto badframe;
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return regs->gprs[2];
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badframe:
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force_sig(SIGSEGV, current);
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return 0;
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}
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asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
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{
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rt_sigframe __user *frame = (rt_sigframe __user *)regs->gprs[15];
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sigset_t set;
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if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
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goto badframe;
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if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
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goto badframe;
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sigdelsetmask(&set, ~_BLOCKABLE);
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spin_lock_irq(¤t->sighand->siglock);
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current->blocked = set;
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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if (restore_sigregs(regs, &frame->uc.uc_mcontext))
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goto badframe;
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if (do_sigaltstack(&frame->uc.uc_stack, NULL,
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regs->gprs[15]) == -EFAULT)
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goto badframe;
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return regs->gprs[2];
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badframe:
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force_sig(SIGSEGV, current);
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return 0;
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}
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/*
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* Set up a signal frame.
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*/
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/*
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* Determine which stack to use..
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*/
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static inline void __user *
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get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
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{
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unsigned long sp;
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/* Default to using normal stack */
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sp = regs->gprs[15];
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/* This is the X/Open sanctioned signal stack switching. */
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if (ka->sa.sa_flags & SA_ONSTACK) {
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if (! sas_ss_flags(sp))
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sp = current->sas_ss_sp + current->sas_ss_size;
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}
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/* This is the legacy signal stack switching. */
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else if (!user_mode(regs) &&
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!(ka->sa.sa_flags & SA_RESTORER) &&
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ka->sa.sa_restorer) {
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sp = (unsigned long) ka->sa.sa_restorer;
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}
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return (void __user *)((sp - frame_size) & -8ul);
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}
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static inline int map_signal(int sig)
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{
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if (current_thread_info()->exec_domain
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&& current_thread_info()->exec_domain->signal_invmap
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&& sig < 32)
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return current_thread_info()->exec_domain->signal_invmap[sig];
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else
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return sig;
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}
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static int setup_frame(int sig, struct k_sigaction *ka,
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sigset_t *set, struct pt_regs * regs)
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{
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sigframe __user *frame;
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frame = get_sigframe(ka, regs, sizeof(sigframe));
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if (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe)))
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goto give_sigsegv;
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if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE))
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goto give_sigsegv;
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if (save_sigregs(regs, &frame->sregs))
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goto give_sigsegv;
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if (__put_user(&frame->sregs, &frame->sc.sregs))
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goto give_sigsegv;
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/* Set up to return from userspace. If provided, use a stub
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already in userspace. */
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if (ka->sa.sa_flags & SA_RESTORER) {
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regs->gprs[14] = (unsigned long)
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ka->sa.sa_restorer | PSW_ADDR_AMODE;
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} else {
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regs->gprs[14] = (unsigned long)
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frame->retcode | PSW_ADDR_AMODE;
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if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn,
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(u16 __user *)(frame->retcode)))
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goto give_sigsegv;
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}
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/* Set up backchain. */
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if (__put_user(regs->gprs[15], (addr_t __user *) frame))
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goto give_sigsegv;
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/* Set up registers for signal handler */
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regs->gprs[15] = (unsigned long) frame;
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regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;
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regs->gprs[2] = map_signal(sig);
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regs->gprs[3] = (unsigned long) &frame->sc;
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/* We forgot to include these in the sigcontext.
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To avoid breaking binary compatibility, they are passed as args. */
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regs->gprs[4] = current->thread.trap_no;
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regs->gprs[5] = current->thread.prot_addr;
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/* Place signal number on stack to allow backtrace from handler. */
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if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
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goto give_sigsegv;
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return 0;
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give_sigsegv:
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force_sigsegv(sig, current);
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return -EFAULT;
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}
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static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
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sigset_t *set, struct pt_regs * regs)
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{
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int err = 0;
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rt_sigframe __user *frame;
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frame = get_sigframe(ka, regs, sizeof(rt_sigframe));
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if (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe)))
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goto give_sigsegv;
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if (copy_siginfo_to_user(&frame->info, info))
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goto give_sigsegv;
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/* Create the ucontext. */
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err |= __put_user(0, &frame->uc.uc_flags);
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err |= __put_user(NULL, &frame->uc.uc_link);
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err |= __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
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err |= __put_user(sas_ss_flags(regs->gprs[15]),
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&frame->uc.uc_stack.ss_flags);
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err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
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err |= save_sigregs(regs, &frame->uc.uc_mcontext);
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err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
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if (err)
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goto give_sigsegv;
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/* Set up to return from userspace. If provided, use a stub
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already in userspace. */
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if (ka->sa.sa_flags & SA_RESTORER) {
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regs->gprs[14] = (unsigned long)
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ka->sa.sa_restorer | PSW_ADDR_AMODE;
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} else {
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regs->gprs[14] = (unsigned long)
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frame->retcode | PSW_ADDR_AMODE;
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if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn,
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(u16 __user *)(frame->retcode)))
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goto give_sigsegv;
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}
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/* Set up backchain. */
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if (__put_user(regs->gprs[15], (addr_t __user *) frame))
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goto give_sigsegv;
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/* Set up registers for signal handler */
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regs->gprs[15] = (unsigned long) frame;
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regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;
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regs->gprs[2] = map_signal(sig);
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regs->gprs[3] = (unsigned long) &frame->info;
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regs->gprs[4] = (unsigned long) &frame->uc;
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return 0;
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give_sigsegv:
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force_sigsegv(sig, current);
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return -EFAULT;
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}
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/*
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* OK, we're invoking a handler
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*/
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static int
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handle_signal(unsigned long sig, struct k_sigaction *ka,
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siginfo_t *info, sigset_t *oldset, struct pt_regs * regs)
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{
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int ret;
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/* Set up the stack frame */
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if (ka->sa.sa_flags & SA_SIGINFO)
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ret = setup_rt_frame(sig, ka, info, oldset, regs);
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else
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ret = setup_frame(sig, ka, oldset, regs);
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if (ret == 0) {
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spin_lock_irq(¤t->sighand->siglock);
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sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask);
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if (!(ka->sa.sa_flags & SA_NODEFER))
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sigaddset(¤t->blocked,sig);
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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}
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return ret;
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}
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/*
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* Note that 'init' is a special process: it doesn't get signals it doesn't
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* want to handle. Thus you cannot kill init even with a SIGKILL even by
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* mistake.
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*
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* Note that we go through the signals twice: once to check the signals that
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* the kernel can handle, and then we build all the user-level signal handling
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* stack-frames in one go after that.
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*/
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void do_signal(struct pt_regs *regs)
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{
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unsigned long retval = 0, continue_addr = 0, restart_addr = 0;
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siginfo_t info;
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int signr;
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struct k_sigaction ka;
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sigset_t *oldset;
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/*
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* We want the common case to go fast, which
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* is why we may in certain cases get here from
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* kernel mode. Just return without doing anything
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* if so.
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*/
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if (!user_mode(regs))
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return;
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if (test_thread_flag(TIF_RESTORE_SIGMASK))
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oldset = ¤t->saved_sigmask;
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else
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oldset = ¤t->blocked;
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/* Are we from a system call? */
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if (regs->trap == __LC_SVC_OLD_PSW) {
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continue_addr = regs->psw.addr;
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restart_addr = continue_addr - regs->ilc;
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retval = regs->gprs[2];
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/* Prepare for system call restart. We do this here so that a
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debugger will see the already changed PSW. */
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switch (retval) {
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case -ERESTARTNOHAND:
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case -ERESTARTSYS:
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case -ERESTARTNOINTR:
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regs->gprs[2] = regs->orig_gpr2;
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regs->psw.addr = restart_addr;
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break;
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case -ERESTART_RESTARTBLOCK:
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regs->gprs[2] = -EINTR;
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}
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}
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/* Get signal to deliver. When running under ptrace, at this point
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the debugger may change all our registers ... */
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signr = get_signal_to_deliver(&info, &ka, regs, NULL);
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/* Depending on the signal settings we may need to revert the
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decision to restart the system call. */
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if (signr > 0 && regs->psw.addr == restart_addr) {
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if (retval == -ERESTARTNOHAND
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|| (retval == -ERESTARTSYS
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&& !(current->sighand->action[signr-1].sa.sa_flags
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& SA_RESTART))) {
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regs->gprs[2] = -EINTR;
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regs->psw.addr = continue_addr;
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}
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}
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if (signr > 0) {
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/* Whee! Actually deliver the signal. */
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#ifdef CONFIG_COMPAT
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if (test_thread_flag(TIF_31BIT)) {
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extern int handle_signal32(unsigned long sig,
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struct k_sigaction *ka,
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siginfo_t *info,
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sigset_t *oldset,
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struct pt_regs *regs);
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if (handle_signal32(
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signr, &ka, &info, oldset, regs) == 0) {
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if (test_thread_flag(TIF_RESTORE_SIGMASK))
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clear_thread_flag(TIF_RESTORE_SIGMASK);
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}
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return;
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}
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#endif
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if (handle_signal(signr, &ka, &info, oldset, regs) == 0) {
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/*
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* A signal was successfully delivered; the saved
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* sigmask will have been stored in the signal frame,
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* and will be restored by sigreturn, so we can simply
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* clear the TIF_RESTORE_SIGMASK flag.
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*/
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if (test_thread_flag(TIF_RESTORE_SIGMASK))
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clear_thread_flag(TIF_RESTORE_SIGMASK);
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}
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return;
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}
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/*
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* If there's no signal to deliver, we just put the saved sigmask back.
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*/
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if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
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clear_thread_flag(TIF_RESTORE_SIGMASK);
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sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
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}
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/* Restart a different system call. */
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if (retval == -ERESTART_RESTARTBLOCK
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&& regs->psw.addr == continue_addr) {
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regs->gprs[2] = __NR_restart_syscall;
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set_thread_flag(TIF_RESTART_SVC);
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}
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}
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