diff options
Diffstat (limited to 'arch/x86/ia32/ia32_signal.c')
| -rw-r--r-- | arch/x86/ia32/ia32_signal.c | 374 |
1 files changed, 374 insertions, 0 deletions
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c new file mode 100644 index 000000000..c9c385932 --- /dev/null +++ b/arch/x86/ia32/ia32_signal.c @@ -0,0 +1,374 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/arch/x86_64/ia32/ia32_signal.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson + * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes + * 2000-12-* x86-64 compatibility mode signal handling by Andi Kleen + */ + +#include <linux/sched.h> +#include <linux/sched/task_stack.h> +#include <linux/mm.h> +#include <linux/smp.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/wait.h> +#include <linux/unistd.h> +#include <linux/stddef.h> +#include <linux/personality.h> +#include <linux/compat.h> +#include <linux/binfmts.h> +#include <linux/syscalls.h> +#include <asm/ucontext.h> +#include <linux/uaccess.h> +#include <asm/fpu/signal.h> +#include <asm/ptrace.h> +#include <asm/ia32_unistd.h> +#include <asm/user32.h> +#include <uapi/asm/sigcontext.h> +#include <asm/proto.h> +#include <asm/vdso.h> +#include <asm/sigframe.h> +#include <asm/sighandling.h> +#include <asm/smap.h> + +static inline void reload_segments(struct sigcontext_32 *sc) +{ + unsigned int cur; + + savesegment(gs, cur); + if ((sc->gs | 0x03) != cur) + load_gs_index(sc->gs | 0x03); + savesegment(fs, cur); + if ((sc->fs | 0x03) != cur) + loadsegment(fs, sc->fs | 0x03); + savesegment(ds, cur); + if ((sc->ds | 0x03) != cur) + loadsegment(ds, sc->ds | 0x03); + savesegment(es, cur); + if ((sc->es | 0x03) != cur) + loadsegment(es, sc->es | 0x03); +} + +/* + * Do a signal return; undo the signal stack. + */ +static bool ia32_restore_sigcontext(struct pt_regs *regs, + struct sigcontext_32 __user *usc) +{ + struct sigcontext_32 sc; + + /* Always make any pending restarted system calls return -EINTR */ + current->restart_block.fn = do_no_restart_syscall; + + if (unlikely(copy_from_user(&sc, usc, sizeof(sc)))) + return false; + + /* Get only the ia32 registers. */ + regs->bx = sc.bx; + regs->cx = sc.cx; + regs->dx = sc.dx; + regs->si = sc.si; + regs->di = sc.di; + regs->bp = sc.bp; + regs->ax = sc.ax; + regs->sp = sc.sp; + regs->ip = sc.ip; + + /* Get CS/SS and force CPL3 */ + regs->cs = sc.cs | 0x03; + regs->ss = sc.ss | 0x03; + + regs->flags = (regs->flags & ~FIX_EFLAGS) | (sc.flags & FIX_EFLAGS); + /* disable syscall checks */ + regs->orig_ax = -1; + + /* + * Reload fs and gs if they have changed in the signal + * handler. This does not handle long fs/gs base changes in + * the handler, but does not clobber them at least in the + * normal case. + */ + reload_segments(&sc); + return fpu__restore_sig(compat_ptr(sc.fpstate), 1); +} + +COMPAT_SYSCALL_DEFINE0(sigreturn) +{ + struct pt_regs *regs = current_pt_regs(); + struct sigframe_ia32 __user *frame = (struct sigframe_ia32 __user *)(regs->sp-8); + sigset_t set; + + if (!access_ok(frame, sizeof(*frame))) + goto badframe; + if (__get_user(set.sig[0], &frame->sc.oldmask) + || __get_user(((__u32 *)&set)[1], &frame->extramask[0])) + goto badframe; + + set_current_blocked(&set); + + if (!ia32_restore_sigcontext(regs, &frame->sc)) + goto badframe; + return regs->ax; + +badframe: + signal_fault(regs, frame, "32bit sigreturn"); + return 0; +} + +COMPAT_SYSCALL_DEFINE0(rt_sigreturn) +{ + struct pt_regs *regs = current_pt_regs(); + struct rt_sigframe_ia32 __user *frame; + sigset_t set; + + frame = (struct rt_sigframe_ia32 __user *)(regs->sp - 4); + + if (!access_ok(frame, sizeof(*frame))) + goto badframe; + if (__get_user(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask)) + goto badframe; + + set_current_blocked(&set); + + if (!ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext)) + goto badframe; + + if (compat_restore_altstack(&frame->uc.uc_stack)) + goto badframe; + + return regs->ax; + +badframe: + signal_fault(regs, frame, "32bit rt sigreturn"); + return 0; +} + +/* + * Set up a signal frame. + */ + +#define get_user_seg(seg) ({ unsigned int v; savesegment(seg, v); v; }) + +static __always_inline int +__unsafe_setup_sigcontext32(struct sigcontext_32 __user *sc, + void __user *fpstate, + struct pt_regs *regs, unsigned int mask) +{ + unsafe_put_user(get_user_seg(gs), (unsigned int __user *)&sc->gs, Efault); + unsafe_put_user(get_user_seg(fs), (unsigned int __user *)&sc->fs, Efault); + unsafe_put_user(get_user_seg(ds), (unsigned int __user *)&sc->ds, Efault); + unsafe_put_user(get_user_seg(es), (unsigned int __user *)&sc->es, Efault); + + unsafe_put_user(regs->di, &sc->di, Efault); + unsafe_put_user(regs->si, &sc->si, Efault); + unsafe_put_user(regs->bp, &sc->bp, Efault); + unsafe_put_user(regs->sp, &sc->sp, Efault); + unsafe_put_user(regs->bx, &sc->bx, Efault); + unsafe_put_user(regs->dx, &sc->dx, Efault); + unsafe_put_user(regs->cx, &sc->cx, Efault); + unsafe_put_user(regs->ax, &sc->ax, Efault); + unsafe_put_user(current->thread.trap_nr, &sc->trapno, Efault); + unsafe_put_user(current->thread.error_code, &sc->err, Efault); + unsafe_put_user(regs->ip, &sc->ip, Efault); + unsafe_put_user(regs->cs, (unsigned int __user *)&sc->cs, Efault); + unsafe_put_user(regs->flags, &sc->flags, Efault); + unsafe_put_user(regs->sp, &sc->sp_at_signal, Efault); + unsafe_put_user(regs->ss, (unsigned int __user *)&sc->ss, Efault); + + unsafe_put_user(ptr_to_compat(fpstate), &sc->fpstate, Efault); + + /* non-iBCS2 extensions.. */ + unsafe_put_user(mask, &sc->oldmask, Efault); + unsafe_put_user(current->thread.cr2, &sc->cr2, Efault); + return 0; + +Efault: + return -EFAULT; +} + +#define unsafe_put_sigcontext32(sc, fp, regs, set, label) \ +do { \ + if (__unsafe_setup_sigcontext32(sc, fp, regs, set->sig[0])) \ + goto label; \ +} while(0) + +/* + * Determine which stack to use.. + */ +static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, + size_t frame_size, + void __user **fpstate) +{ + unsigned long sp, fx_aligned, math_size; + + /* Default to using normal stack */ + sp = regs->sp; + + /* This is the X/Open sanctioned signal stack switching. */ + if (ksig->ka.sa.sa_flags & SA_ONSTACK) + sp = sigsp(sp, ksig); + /* This is the legacy signal stack switching. */ + else if (regs->ss != __USER32_DS && + !(ksig->ka.sa.sa_flags & SA_RESTORER) && + ksig->ka.sa.sa_restorer) + sp = (unsigned long) ksig->ka.sa.sa_restorer; + + sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size); + *fpstate = (struct _fpstate_32 __user *) sp; + if (!copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned, + math_size)) + return (void __user *) -1L; + + sp -= frame_size; + /* Align the stack pointer according to the i386 ABI, + * i.e. so that on function entry ((sp + 4) & 15) == 0. */ + sp = ((sp + 4) & -16ul) - 4; + return (void __user *) sp; +} + +int ia32_setup_frame(int sig, struct ksignal *ksig, + compat_sigset_t *set, struct pt_regs *regs) +{ + struct sigframe_ia32 __user *frame; + void __user *restorer; + void __user *fp = NULL; + + /* copy_to_user optimizes that into a single 8 byte store */ + static const struct { + u16 poplmovl; + u32 val; + u16 int80; + } __attribute__((packed)) code = { + 0xb858, /* popl %eax ; movl $...,%eax */ + __NR_ia32_sigreturn, + 0x80cd, /* int $0x80 */ + }; + + frame = get_sigframe(ksig, regs, sizeof(*frame), &fp); + + if (ksig->ka.sa.sa_flags & SA_RESTORER) { + restorer = ksig->ka.sa.sa_restorer; + } else { + /* Return stub is in 32bit vsyscall page */ + if (current->mm->context.vdso) + restorer = current->mm->context.vdso + + vdso_image_32.sym___kernel_sigreturn; + else + restorer = &frame->retcode; + } + + if (!user_access_begin(frame, sizeof(*frame))) + return -EFAULT; + + unsafe_put_user(sig, &frame->sig, Efault); + unsafe_put_sigcontext32(&frame->sc, fp, regs, set, Efault); + unsafe_put_user(set->sig[1], &frame->extramask[0], Efault); + unsafe_put_user(ptr_to_compat(restorer), &frame->pretcode, Efault); + /* + * These are actually not used anymore, but left because some + * gdb versions depend on them as a marker. + */ + unsafe_put_user(*((u64 *)&code), (u64 __user *)frame->retcode, Efault); + user_access_end(); + + /* 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 = 0; + regs->cx = 0; + + loadsegment(ds, __USER32_DS); + loadsegment(es, __USER32_DS); + + regs->cs = __USER32_CS; + regs->ss = __USER32_DS; + + return 0; +Efault: + user_access_end(); + return -EFAULT; +} + +int ia32_setup_rt_frame(int sig, struct ksignal *ksig, + compat_sigset_t *set, struct pt_regs *regs) +{ + struct rt_sigframe_ia32 __user *frame; + void __user *restorer; + void __user *fp = NULL; + + /* unsafe_put_user optimizes that into a single 8 byte store */ + static const struct { + u8 movl; + u32 val; + u16 int80; + u8 pad; + } __attribute__((packed)) code = { + 0xb8, + __NR_ia32_rt_sigreturn, + 0x80cd, + 0, + }; + + frame = get_sigframe(ksig, regs, sizeof(*frame), &fp); + + if (!user_access_begin(frame, sizeof(*frame))) + return -EFAULT; + + unsafe_put_user(sig, &frame->sig, Efault); + unsafe_put_user(ptr_to_compat(&frame->info), &frame->pinfo, Efault); + unsafe_put_user(ptr_to_compat(&frame->uc), &frame->puc, Efault); + + /* Create the ucontext. */ + if (static_cpu_has(X86_FEATURE_XSAVE)) + unsafe_put_user(UC_FP_XSTATE, &frame->uc.uc_flags, Efault); + else + unsafe_put_user(0, &frame->uc.uc_flags, Efault); + unsafe_put_user(0, &frame->uc.uc_link, Efault); + unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->sp, Efault); + + if (ksig->ka.sa.sa_flags & SA_RESTORER) + restorer = ksig->ka.sa.sa_restorer; + else + restorer = current->mm->context.vdso + + vdso_image_32.sym___kernel_rt_sigreturn; + unsafe_put_user(ptr_to_compat(restorer), &frame->pretcode, Efault); + + /* + * Not actually used anymore, but left because some gdb + * versions need it. + */ + unsafe_put_user(*((u64 *)&code), (u64 __user *)frame->retcode, Efault); + unsafe_put_sigcontext32(&frame->uc.uc_mcontext, fp, regs, set, Efault); + unsafe_put_user(*(__u64 *)set, (__u64 __user *)&frame->uc.uc_sigmask, Efault); + user_access_end(); + + if (__copy_siginfo_to_user32(&frame->info, &ksig->info)) + 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; +} |