375 lines
10 KiB
C
375 lines
10 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/arch/x86_64/ia32/ia32_signal.c
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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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* 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
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* 2000-12-* x86-64 compatibility mode signal handling by Andi Kleen
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*/
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#include <linux/sched.h>
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#include <linux/sched/task_stack.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/wait.h>
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#include <linux/unistd.h>
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#include <linux/stddef.h>
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#include <linux/personality.h>
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#include <linux/compat.h>
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#include <linux/binfmts.h>
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#include <linux/syscalls.h>
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#include <asm/ucontext.h>
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#include <linux/uaccess.h>
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#include <asm/fpu/signal.h>
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#include <asm/ptrace.h>
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#include <asm/ia32_unistd.h>
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#include <asm/user32.h>
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#include <uapi/asm/sigcontext.h>
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#include <asm/proto.h>
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#include <asm/vdso.h>
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#include <asm/sigframe.h>
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#include <asm/sighandling.h>
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#include <asm/smap.h>
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static inline void reload_segments(struct sigcontext_32 *sc)
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{
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unsigned int cur;
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savesegment(gs, cur);
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if ((sc->gs | 0x03) != cur)
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load_gs_index(sc->gs | 0x03);
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savesegment(fs, cur);
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if ((sc->fs | 0x03) != cur)
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loadsegment(fs, sc->fs | 0x03);
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savesegment(ds, cur);
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if ((sc->ds | 0x03) != cur)
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loadsegment(ds, sc->ds | 0x03);
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savesegment(es, cur);
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if ((sc->es | 0x03) != cur)
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loadsegment(es, sc->es | 0x03);
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}
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/*
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* Do a signal return; undo the signal stack.
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*/
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static bool ia32_restore_sigcontext(struct pt_regs *regs,
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struct sigcontext_32 __user *usc)
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{
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struct sigcontext_32 sc;
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/* Always make any pending restarted system calls return -EINTR */
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current->restart_block.fn = do_no_restart_syscall;
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if (unlikely(copy_from_user(&sc, usc, sizeof(sc))))
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return false;
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/* Get only the ia32 registers. */
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regs->bx = sc.bx;
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regs->cx = sc.cx;
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regs->dx = sc.dx;
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regs->si = sc.si;
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regs->di = sc.di;
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regs->bp = sc.bp;
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regs->ax = sc.ax;
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regs->sp = sc.sp;
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regs->ip = sc.ip;
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/* Get CS/SS and force CPL3 */
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regs->cs = sc.cs | 0x03;
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regs->ss = sc.ss | 0x03;
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regs->flags = (regs->flags & ~FIX_EFLAGS) | (sc.flags & FIX_EFLAGS);
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/* disable syscall checks */
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regs->orig_ax = -1;
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/*
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* Reload fs and gs if they have changed in the signal
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* handler. This does not handle long fs/gs base changes in
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* the handler, but does not clobber them at least in the
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* normal case.
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*/
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reload_segments(&sc);
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return fpu__restore_sig(compat_ptr(sc.fpstate), 1);
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}
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COMPAT_SYSCALL_DEFINE0(sigreturn)
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{
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struct pt_regs *regs = current_pt_regs();
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struct sigframe_ia32 __user *frame = (struct sigframe_ia32 __user *)(regs->sp-8);
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sigset_t set;
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if (!access_ok(frame, sizeof(*frame)))
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goto badframe;
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if (__get_user(set.sig[0], &frame->sc.oldmask)
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|| __get_user(((__u32 *)&set)[1], &frame->extramask[0]))
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goto badframe;
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set_current_blocked(&set);
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if (!ia32_restore_sigcontext(regs, &frame->sc))
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goto badframe;
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return regs->ax;
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badframe:
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signal_fault(regs, frame, "32bit sigreturn");
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return 0;
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}
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COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
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{
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struct pt_regs *regs = current_pt_regs();
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struct rt_sigframe_ia32 __user *frame;
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sigset_t set;
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frame = (struct rt_sigframe_ia32 __user *)(regs->sp - 4);
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if (!access_ok(frame, sizeof(*frame)))
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goto badframe;
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if (__get_user(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask))
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goto badframe;
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set_current_blocked(&set);
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if (!ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext))
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goto badframe;
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if (compat_restore_altstack(&frame->uc.uc_stack))
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goto badframe;
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return regs->ax;
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badframe:
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signal_fault(regs, frame, "32bit rt sigreturn");
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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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#define get_user_seg(seg) ({ unsigned int v; savesegment(seg, v); v; })
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static __always_inline int
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__unsafe_setup_sigcontext32(struct sigcontext_32 __user *sc,
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void __user *fpstate,
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struct pt_regs *regs, unsigned int mask)
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{
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unsafe_put_user(get_user_seg(gs), (unsigned int __user *)&sc->gs, Efault);
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unsafe_put_user(get_user_seg(fs), (unsigned int __user *)&sc->fs, Efault);
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unsafe_put_user(get_user_seg(ds), (unsigned int __user *)&sc->ds, Efault);
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unsafe_put_user(get_user_seg(es), (unsigned int __user *)&sc->es, Efault);
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unsafe_put_user(regs->di, &sc->di, Efault);
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unsafe_put_user(regs->si, &sc->si, Efault);
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unsafe_put_user(regs->bp, &sc->bp, Efault);
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unsafe_put_user(regs->sp, &sc->sp, Efault);
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unsafe_put_user(regs->bx, &sc->bx, Efault);
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unsafe_put_user(regs->dx, &sc->dx, Efault);
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unsafe_put_user(regs->cx, &sc->cx, Efault);
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unsafe_put_user(regs->ax, &sc->ax, Efault);
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unsafe_put_user(current->thread.trap_nr, &sc->trapno, Efault);
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unsafe_put_user(current->thread.error_code, &sc->err, Efault);
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unsafe_put_user(regs->ip, &sc->ip, Efault);
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unsafe_put_user(regs->cs, (unsigned int __user *)&sc->cs, Efault);
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unsafe_put_user(regs->flags, &sc->flags, Efault);
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unsafe_put_user(regs->sp, &sc->sp_at_signal, Efault);
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unsafe_put_user(regs->ss, (unsigned int __user *)&sc->ss, Efault);
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unsafe_put_user(ptr_to_compat(fpstate), &sc->fpstate, Efault);
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/* non-iBCS2 extensions.. */
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unsafe_put_user(mask, &sc->oldmask, Efault);
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unsafe_put_user(current->thread.cr2, &sc->cr2, Efault);
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return 0;
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Efault:
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return -EFAULT;
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}
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#define unsafe_put_sigcontext32(sc, fp, regs, set, label) \
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do { \
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if (__unsafe_setup_sigcontext32(sc, fp, regs, set->sig[0])) \
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goto label; \
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} while(0)
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/*
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* Determine which stack to use..
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*/
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static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
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size_t frame_size,
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void __user **fpstate)
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{
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unsigned long sp, fx_aligned, math_size;
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/* Default to using normal stack */
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sp = regs->sp;
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/* This is the X/Open sanctioned signal stack switching. */
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if (ksig->ka.sa.sa_flags & SA_ONSTACK)
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sp = sigsp(sp, ksig);
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/* This is the legacy signal stack switching. */
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else if (regs->ss != __USER32_DS &&
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!(ksig->ka.sa.sa_flags & SA_RESTORER) &&
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ksig->ka.sa.sa_restorer)
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sp = (unsigned long) ksig->ka.sa.sa_restorer;
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sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size);
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*fpstate = (struct _fpstate_32 __user *) sp;
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if (!copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned,
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math_size))
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return (void __user *) -1L;
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sp -= frame_size;
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/* Align the stack pointer according to the i386 ABI,
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* i.e. so that on function entry ((sp + 4) & 15) == 0. */
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sp = ((sp + 4) & -16ul) - 4;
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return (void __user *) sp;
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}
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int ia32_setup_frame(int sig, struct ksignal *ksig,
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compat_sigset_t *set, struct pt_regs *regs)
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{
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struct sigframe_ia32 __user *frame;
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void __user *restorer;
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void __user *fp = NULL;
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/* copy_to_user optimizes that into a single 8 byte store */
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static const struct {
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u16 poplmovl;
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u32 val;
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u16 int80;
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} __attribute__((packed)) code = {
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0xb858, /* popl %eax ; movl $...,%eax */
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__NR_ia32_sigreturn,
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0x80cd, /* int $0x80 */
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};
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frame = get_sigframe(ksig, regs, sizeof(*frame), &fp);
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if (ksig->ka.sa.sa_flags & SA_RESTORER) {
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restorer = ksig->ka.sa.sa_restorer;
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} else {
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/* Return stub is in 32bit vsyscall page */
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if (current->mm->context.vdso)
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restorer = current->mm->context.vdso +
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vdso_image_32.sym___kernel_sigreturn;
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else
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restorer = &frame->retcode;
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}
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if (!user_access_begin(frame, sizeof(*frame)))
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return -EFAULT;
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unsafe_put_user(sig, &frame->sig, Efault);
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unsafe_put_sigcontext32(&frame->sc, fp, regs, set, Efault);
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unsafe_put_user(set->sig[1], &frame->extramask[0], Efault);
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unsafe_put_user(ptr_to_compat(restorer), &frame->pretcode, Efault);
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/*
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* These are actually not used anymore, but left because some
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* gdb versions depend on them as a marker.
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*/
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unsafe_put_user(*((u64 *)&code), (u64 __user *)frame->retcode, Efault);
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user_access_end();
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/* Set up registers for signal handler */
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regs->sp = (unsigned long) frame;
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regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
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/* Make -mregparm=3 work */
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regs->ax = sig;
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regs->dx = 0;
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regs->cx = 0;
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loadsegment(ds, __USER32_DS);
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loadsegment(es, __USER32_DS);
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regs->cs = __USER32_CS;
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regs->ss = __USER32_DS;
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return 0;
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Efault:
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user_access_end();
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return -EFAULT;
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}
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int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
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compat_sigset_t *set, struct pt_regs *regs)
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{
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struct rt_sigframe_ia32 __user *frame;
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void __user *restorer;
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void __user *fp = NULL;
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/* unsafe_put_user optimizes that into a single 8 byte store */
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static const struct {
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u8 movl;
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u32 val;
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u16 int80;
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u8 pad;
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} __attribute__((packed)) code = {
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0xb8,
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__NR_ia32_rt_sigreturn,
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0x80cd,
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0,
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};
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frame = get_sigframe(ksig, regs, sizeof(*frame), &fp);
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if (!user_access_begin(frame, sizeof(*frame)))
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return -EFAULT;
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unsafe_put_user(sig, &frame->sig, Efault);
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unsafe_put_user(ptr_to_compat(&frame->info), &frame->pinfo, Efault);
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unsafe_put_user(ptr_to_compat(&frame->uc), &frame->puc, Efault);
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/* Create the ucontext. */
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if (static_cpu_has(X86_FEATURE_XSAVE))
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unsafe_put_user(UC_FP_XSTATE, &frame->uc.uc_flags, Efault);
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else
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unsafe_put_user(0, &frame->uc.uc_flags, Efault);
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unsafe_put_user(0, &frame->uc.uc_link, Efault);
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unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
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if (ksig->ka.sa.sa_flags & SA_RESTORER)
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restorer = ksig->ka.sa.sa_restorer;
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else
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restorer = current->mm->context.vdso +
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vdso_image_32.sym___kernel_rt_sigreturn;
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unsafe_put_user(ptr_to_compat(restorer), &frame->pretcode, Efault);
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/*
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* Not actually used anymore, but left because some gdb
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* versions need it.
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*/
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unsafe_put_user(*((u64 *)&code), (u64 __user *)frame->retcode, Efault);
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unsafe_put_sigcontext32(&frame->uc.uc_mcontext, fp, regs, set, Efault);
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unsafe_put_user(*(__u64 *)set, (__u64 __user *)&frame->uc.uc_sigmask, Efault);
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user_access_end();
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if (__copy_siginfo_to_user32(&frame->info, &ksig->info))
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return -EFAULT;
|
||
|
|
|
||
|
|
/* Set up registers for signal handler */
|
||
|
|
regs->sp = (unsigned long) frame;
|
||
|
|
regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
|
||
|
|
|
||
|
|
/* Make -mregparm=3 work */
|
||
|
|
regs->ax = sig;
|
||
|
|
regs->dx = (unsigned long) &frame->info;
|
||
|
|
regs->cx = (unsigned long) &frame->uc;
|
||
|
|
|
||
|
|
loadsegment(ds, __USER32_DS);
|
||
|
|
loadsegment(es, __USER32_DS);
|
||
|
|
|
||
|
|
regs->cs = __USER32_CS;
|
||
|
|
regs->ss = __USER32_DS;
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
Efault:
|
||
|
|
user_access_end();
|
||
|
|
return -EFAULT;
|
||
|
|
}
|