| /* |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs |
| * |
| * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson |
| * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes |
| * 2000-2002 x86-64 support by Andi Kleen |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/sched.h> |
| #include <linux/mm.h> |
| #include <linux/smp.h> |
| #include <linux/kernel.h> |
| #include <linux/errno.h> |
| #include <linux/wait.h> |
| #include <linux/tracehook.h> |
| #include <linux/unistd.h> |
| #include <linux/stddef.h> |
| #include <linux/personality.h> |
| #include <linux/uaccess.h> |
| #include <linux/user-return-notifier.h> |
| #include <linux/uprobes.h> |
| #include <linux/context_tracking.h> |
| |
| #include <asm/processor.h> |
| #include <asm/ucontext.h> |
| #include <asm/fpu/internal.h> |
| #include <asm/fpu/signal.h> |
| #include <asm/vdso.h> |
| #include <asm/mce.h> |
| #include <asm/sighandling.h> |
| #include <asm/vm86.h> |
| |
| #ifdef CONFIG_X86_64 |
| #include <asm/proto.h> |
| #include <asm/ia32_unistd.h> |
| #endif /* CONFIG_X86_64 */ |
| |
| #include <asm/syscall.h> |
| #include <asm/syscalls.h> |
| |
| #include <asm/sigframe.h> |
| #include <asm/signal.h> |
| |
| #define COPY(x) do { \ |
| get_user_ex(regs->x, &sc->x); \ |
| } while (0) |
| |
| #define GET_SEG(seg) ({ \ |
| unsigned short tmp; \ |
| get_user_ex(tmp, &sc->seg); \ |
| tmp; \ |
| }) |
| |
| #define COPY_SEG(seg) do { \ |
| regs->seg = GET_SEG(seg); \ |
| } while (0) |
| |
| #define COPY_SEG_CPL3(seg) do { \ |
| regs->seg = GET_SEG(seg) | 3; \ |
| } while (0) |
| |
| #ifdef CONFIG_X86_64 |
| /* |
| * If regs->ss will cause an IRET fault, change it. Otherwise leave it |
| * alone. Using this generally makes no sense unless |
| * user_64bit_mode(regs) would return true. |
| */ |
| static void force_valid_ss(struct pt_regs *regs) |
| { |
| u32 ar; |
| asm volatile ("lar %[old_ss], %[ar]\n\t" |
| "jz 1f\n\t" /* If invalid: */ |
| "xorl %[ar], %[ar]\n\t" /* set ar = 0 */ |
| "1:" |
| : [ar] "=r" (ar) |
| : [old_ss] "rm" ((u16)regs->ss)); |
| |
| /* |
| * For a valid 64-bit user context, we need DPL 3, type |
| * read-write data or read-write exp-down data, and S and P |
| * set. We can't use VERW because VERW doesn't check the |
| * P bit. |
| */ |
| ar &= AR_DPL_MASK | AR_S | AR_P | AR_TYPE_MASK; |
| if (ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA) && |
| ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA_EXPDOWN)) |
| regs->ss = __USER_DS; |
| } |
| #endif |
| |
| static int restore_sigcontext(struct pt_regs *regs, |
| struct sigcontext __user *sc, |
| unsigned long uc_flags) |
| { |
| unsigned long buf_val; |
| void __user *buf; |
| unsigned int tmpflags; |
| unsigned int err = 0; |
| |
| /* Always make any pending restarted system calls return -EINTR */ |
| current->restart_block.fn = do_no_restart_syscall; |
| |
| get_user_try { |
| |
| #ifdef CONFIG_X86_32 |
| set_user_gs(regs, GET_SEG(gs)); |
| COPY_SEG(fs); |
| COPY_SEG(es); |
| COPY_SEG(ds); |
| #endif /* CONFIG_X86_32 */ |
| |
| COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx); |
| COPY(dx); COPY(cx); COPY(ip); COPY(ax); |
| |
| #ifdef CONFIG_X86_64 |
| COPY(r8); |
| COPY(r9); |
| COPY(r10); |
| COPY(r11); |
| COPY(r12); |
| COPY(r13); |
| COPY(r14); |
| COPY(r15); |
| #endif /* CONFIG_X86_64 */ |
| |
| COPY_SEG_CPL3(cs); |
| COPY_SEG_CPL3(ss); |
| |
| #ifdef CONFIG_X86_64 |
| /* |
| * Fix up SS if needed for the benefit of old DOSEMU and |
| * CRIU. |
| */ |
| if (unlikely(!(uc_flags & UC_STRICT_RESTORE_SS) && |
| user_64bit_mode(regs))) |
| force_valid_ss(regs); |
| #endif |
| |
| get_user_ex(tmpflags, &sc->flags); |
| regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS); |
| regs->orig_ax = -1; /* disable syscall checks */ |
| |
| get_user_ex(buf_val, &sc->fpstate); |
| buf = (void __user *)buf_val; |
| } get_user_catch(err); |
| |
| err |= fpu__restore_sig(buf, IS_ENABLED(CONFIG_X86_32)); |
| |
| force_iret(); |
| |
| return err; |
| } |
| |
| int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate, |
| struct pt_regs *regs, unsigned long mask) |
| { |
| int err = 0; |
| |
| put_user_try { |
| |
| #ifdef CONFIG_X86_32 |
| put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs); |
| put_user_ex(regs->fs, (unsigned int __user *)&sc->fs); |
| put_user_ex(regs->es, (unsigned int __user *)&sc->es); |
| put_user_ex(regs->ds, (unsigned int __user *)&sc->ds); |
| #endif /* CONFIG_X86_32 */ |
| |
| put_user_ex(regs->di, &sc->di); |
| put_user_ex(regs->si, &sc->si); |
| put_user_ex(regs->bp, &sc->bp); |
| put_user_ex(regs->sp, &sc->sp); |
| put_user_ex(regs->bx, &sc->bx); |
| put_user_ex(regs->dx, &sc->dx); |
| put_user_ex(regs->cx, &sc->cx); |
| put_user_ex(regs->ax, &sc->ax); |
| #ifdef CONFIG_X86_64 |
| put_user_ex(regs->r8, &sc->r8); |
| put_user_ex(regs->r9, &sc->r9); |
| put_user_ex(regs->r10, &sc->r10); |
| put_user_ex(regs->r11, &sc->r11); |
| put_user_ex(regs->r12, &sc->r12); |
| put_user_ex(regs->r13, &sc->r13); |
| put_user_ex(regs->r14, &sc->r14); |
| put_user_ex(regs->r15, &sc->r15); |
| #endif /* CONFIG_X86_64 */ |
| |
| put_user_ex(current->thread.trap_nr, &sc->trapno); |
| put_user_ex(current->thread.error_code, &sc->err); |
| put_user_ex(regs->ip, &sc->ip); |
| #ifdef CONFIG_X86_32 |
| put_user_ex(regs->cs, (unsigned int __user *)&sc->cs); |
| put_user_ex(regs->flags, &sc->flags); |
| put_user_ex(regs->sp, &sc->sp_at_signal); |
| put_user_ex(regs->ss, (unsigned int __user *)&sc->ss); |
| #else /* !CONFIG_X86_32 */ |
| put_user_ex(regs->flags, &sc->flags); |
| put_user_ex(regs->cs, &sc->cs); |
| put_user_ex(0, &sc->gs); |
| put_user_ex(0, &sc->fs); |
| put_user_ex(regs->ss, &sc->ss); |
| #endif /* CONFIG_X86_32 */ |
| |
| put_user_ex(fpstate, &sc->fpstate); |
| |
| /* non-iBCS2 extensions.. */ |
| put_user_ex(mask, &sc->oldmask); |
| put_user_ex(current->thread.cr2, &sc->cr2); |
| } put_user_catch(err); |
| |
| return err; |
| } |
| |
| /* |
| * Set up a signal frame. |
| */ |
| |
| /* |
| * Determine which stack to use.. |
| */ |
| static unsigned long align_sigframe(unsigned long sp) |
| { |
| #ifdef CONFIG_X86_32 |
| /* |
| * 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; |
| #else /* !CONFIG_X86_32 */ |
| sp = round_down(sp, 16) - 8; |
| #endif |
| return sp; |
| } |
| |
| static void __user * |
| get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, |
| void __user **fpstate) |
| { |
| /* Default to using normal stack */ |
| unsigned long math_size = 0; |
| unsigned long sp = regs->sp; |
| unsigned long buf_fx = 0; |
| int onsigstack = on_sig_stack(sp); |
| struct fpu *fpu = ¤t->thread.fpu; |
| |
| /* redzone */ |
| if (IS_ENABLED(CONFIG_X86_64)) |
| sp -= 128; |
| |
| /* This is the X/Open sanctioned signal stack switching. */ |
| if (ka->sa.sa_flags & SA_ONSTACK) { |
| if (sas_ss_flags(sp) == 0) |
| sp = current->sas_ss_sp + current->sas_ss_size; |
| } else if (IS_ENABLED(CONFIG_X86_32) && |
| !onsigstack && |
| (regs->ss & 0xffff) != __USER_DS && |
| !(ka->sa.sa_flags & SA_RESTORER) && |
| ka->sa.sa_restorer) { |
| /* This is the legacy signal stack switching. */ |
| sp = (unsigned long) ka->sa.sa_restorer; |
| } |
| |
| if (fpu->fpstate_active) { |
| sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32), |
| &buf_fx, &math_size); |
| *fpstate = (void __user *)sp; |
| } |
| |
| sp = align_sigframe(sp - frame_size); |
| |
| /* |
| * If we are on the alternate signal stack and would overflow it, don't. |
| * Return an always-bogus address instead so we will die with SIGSEGV. |
| */ |
| if (onsigstack && !likely(on_sig_stack(sp))) |
| return (void __user *)-1L; |
| |
| /* save i387 and extended state */ |
| if (fpu->fpstate_active && |
| copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size) < 0) |
| return (void __user *)-1L; |
| |
| return (void __user *)sp; |
| } |
| |
| #ifdef CONFIG_X86_32 |
| static const struct { |
| u16 poplmovl; |
| u32 val; |
| u16 int80; |
| } __attribute__((packed)) retcode = { |
| 0xb858, /* popl %eax; movl $..., %eax */ |
| __NR_sigreturn, |
| 0x80cd, /* int $0x80 */ |
| }; |
| |
| static const struct { |
| u8 movl; |
| u32 val; |
| u16 int80; |
| u8 pad; |
| } __attribute__((packed)) rt_retcode = { |
| 0xb8, /* movl $..., %eax */ |
| __NR_rt_sigreturn, |
| 0x80cd, /* int $0x80 */ |
| 0 |
| }; |
| |
| static int |
| __setup_frame(int sig, struct ksignal *ksig, sigset_t *set, |
| struct pt_regs *regs) |
| { |
| struct sigframe __user *frame; |
| void __user *restorer; |
| int err = 0; |
| void __user *fpstate = NULL; |
| |
| frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); |
| |
| if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) |
| return -EFAULT; |
| |
| if (__put_user(sig, &frame->sig)) |
| return -EFAULT; |
| |
| if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0])) |
| return -EFAULT; |
| |
| if (_NSIG_WORDS > 1) { |
| if (__copy_to_user(&frame->extramask, &set->sig[1], |
| sizeof(frame->extramask))) |
| return -EFAULT; |
| } |
| |
| if (current->mm->context.vdso) |
| restorer = current->mm->context.vdso + |
| vdso_image_32.sym___kernel_sigreturn; |
| else |
| restorer = &frame->retcode; |
| if (ksig->ka.sa.sa_flags & SA_RESTORER) |
| restorer = ksig->ka.sa.sa_restorer; |
| |
| /* Set up to return from userspace. */ |
| err |= __put_user(restorer, &frame->pretcode); |
| |
| /* |
| * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80 |
| * |
| * WE DO NOT USE IT ANY MORE! It's only left here for historical |
| * reasons and because gdb uses it as a signature to notice |
| * signal handler stack frames. |
| */ |
| err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode); |
| |
| if (err) |
| return -EFAULT; |
| |
| /* Set up registers for signal handler */ |
| regs->sp = (unsigned long)frame; |
| regs->ip = (unsigned long)ksig->ka.sa.sa_handler; |
| regs->ax = (unsigned long)sig; |
| regs->dx = 0; |
| regs->cx = 0; |
| |
| regs->ds = __USER_DS; |
| regs->es = __USER_DS; |
| regs->ss = __USER_DS; |
| regs->cs = __USER_CS; |
| |
| return 0; |
| } |
| |
| static int __setup_rt_frame(int sig, struct ksignal *ksig, |
| sigset_t *set, struct pt_regs *regs) |
| { |
| struct rt_sigframe __user *frame; |
| void __user *restorer; |
| int err = 0; |
| void __user *fpstate = NULL; |
| |
| frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); |
| |
| if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) |
| return -EFAULT; |
| |
| put_user_try { |
| put_user_ex(sig, &frame->sig); |
| put_user_ex(&frame->info, &frame->pinfo); |
| put_user_ex(&frame->uc, &frame->puc); |
| |
| /* Create the ucontext. */ |
| if (boot_cpu_has(X86_FEATURE_XSAVE)) |
| put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags); |
| else |
| put_user_ex(0, &frame->uc.uc_flags); |
| put_user_ex(0, &frame->uc.uc_link); |
| save_altstack_ex(&frame->uc.uc_stack, regs->sp); |
| |
| /* Set up to return from userspace. */ |
| restorer = current->mm->context.vdso + |
| vdso_image_32.sym___kernel_rt_sigreturn; |
| if (ksig->ka.sa.sa_flags & SA_RESTORER) |
| restorer = ksig->ka.sa.sa_restorer; |
| put_user_ex(restorer, &frame->pretcode); |
| |
| /* |
| * This is movl $__NR_rt_sigreturn, %ax ; int $0x80 |
| * |
| * WE DO NOT USE IT ANY MORE! It's only left here for historical |
| * reasons and because gdb uses it as a signature to notice |
| * signal handler stack frames. |
| */ |
| put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode); |
| } put_user_catch(err); |
| |
| err |= copy_siginfo_to_user(&frame->info, &ksig->info); |
| err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate, |
| regs, set->sig[0]); |
| err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); |
| |
| if (err) |
| return -EFAULT; |
| |
| /* Set up registers for signal handler */ |
| regs->sp = (unsigned long)frame; |
| regs->ip = (unsigned long)ksig->ka.sa.sa_handler; |
| regs->ax = (unsigned long)sig; |
| regs->dx = (unsigned long)&frame->info; |
| regs->cx = (unsigned long)&frame->uc; |
| |
| regs->ds = __USER_DS; |
| regs->es = __USER_DS; |
| regs->ss = __USER_DS; |
| regs->cs = __USER_CS; |
| |
| return 0; |
| } |
| #else /* !CONFIG_X86_32 */ |
| static unsigned long frame_uc_flags(struct pt_regs *regs) |
| { |
| unsigned long flags; |
| |
| if (boot_cpu_has(X86_FEATURE_XSAVE)) |
| flags = UC_FP_XSTATE | UC_SIGCONTEXT_SS; |
| else |
| flags = UC_SIGCONTEXT_SS; |
| |
| if (likely(user_64bit_mode(regs))) |
| flags |= UC_STRICT_RESTORE_SS; |
| |
| return flags; |
| } |
| |
| static int __setup_rt_frame(int sig, struct ksignal *ksig, |
| sigset_t *set, struct pt_regs *regs) |
| { |
| struct rt_sigframe __user *frame; |
| void __user *fp = NULL; |
| int err = 0; |
| |
| frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp); |
| |
| if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) |
| return -EFAULT; |
| |
| if (ksig->ka.sa.sa_flags & SA_SIGINFO) { |
| if (copy_siginfo_to_user(&frame->info, &ksig->info)) |
| return -EFAULT; |
| } |
| |
| put_user_try { |
| /* Create the ucontext. */ |
| put_user_ex(frame_uc_flags(regs), &frame->uc.uc_flags); |
| put_user_ex(0, &frame->uc.uc_link); |
| save_altstack_ex(&frame->uc.uc_stack, regs->sp); |
| |
| /* Set up to return from userspace. If provided, use a stub |
| already in userspace. */ |
| /* x86-64 should always use SA_RESTORER. */ |
| if (ksig->ka.sa.sa_flags & SA_RESTORER) { |
| put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode); |
| } else { |
| /* could use a vstub here */ |
| err |= -EFAULT; |
| } |
| } put_user_catch(err); |
| |
| err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]); |
| err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); |
| |
| if (err) |
| return -EFAULT; |
| |
| /* Set up registers for signal handler */ |
| regs->di = sig; |
| /* In case the signal handler was declared without prototypes */ |
| regs->ax = 0; |
| |
| /* This also works for non SA_SIGINFO handlers because they expect the |
| next argument after the signal number on the stack. */ |
| regs->si = (unsigned long)&frame->info; |
| regs->dx = (unsigned long)&frame->uc; |
| regs->ip = (unsigned long) ksig->ka.sa.sa_handler; |
| |
| regs->sp = (unsigned long)frame; |
| |
| /* |
| * Set up the CS and SS registers to run signal handlers in |
| * 64-bit mode, even if the handler happens to be interrupting |
| * 32-bit or 16-bit code. |
| * |
| * SS is subtle. In 64-bit mode, we don't need any particular |
| * SS descriptor, but we do need SS to be valid. It's possible |
| * that the old SS is entirely bogus -- this can happen if the |
| * signal we're trying to deliver is #GP or #SS caused by a bad |
| * SS value. We also have a compatbility issue here: DOSEMU |
| * relies on the contents of the SS register indicating the |
| * SS value at the time of the signal, even though that code in |
| * DOSEMU predates sigreturn's ability to restore SS. (DOSEMU |
| * avoids relying on sigreturn to restore SS; instead it uses |
| * a trampoline.) So we do our best: if the old SS was valid, |
| * we keep it. Otherwise we replace it. |
| */ |
| regs->cs = __USER_CS; |
| |
| if (unlikely(regs->ss != __USER_DS)) |
| force_valid_ss(regs); |
| |
| return 0; |
| } |
| #endif /* CONFIG_X86_32 */ |
| |
| static int x32_setup_rt_frame(struct ksignal *ksig, |
| compat_sigset_t *set, |
| struct pt_regs *regs) |
| { |
| #ifdef CONFIG_X86_X32_ABI |
| struct rt_sigframe_x32 __user *frame; |
| void __user *restorer; |
| int err = 0; |
| void __user *fpstate = NULL; |
| |
| frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate); |
| |
| if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) |
| return -EFAULT; |
| |
| if (ksig->ka.sa.sa_flags & SA_SIGINFO) { |
| if (__copy_siginfo_to_user32(&frame->info, &ksig->info, true)) |
| return -EFAULT; |
| } |
| |
| put_user_try { |
| /* Create the ucontext. */ |
| put_user_ex(frame_uc_flags(regs), &frame->uc.uc_flags); |
| put_user_ex(0, &frame->uc.uc_link); |
| compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp); |
| put_user_ex(0, &frame->uc.uc__pad0); |
| |
| if (ksig->ka.sa.sa_flags & SA_RESTORER) { |
| restorer = ksig->ka.sa.sa_restorer; |
| } else { |
| /* could use a vstub here */ |
| restorer = NULL; |
| err |= -EFAULT; |
| } |
| put_user_ex(restorer, &frame->pretcode); |
| } put_user_catch(err); |
| |
| err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate, |
| regs, set->sig[0]); |
| err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); |
| |
| if (err) |
| return -EFAULT; |
| |
| /* Set up registers for signal handler */ |
| regs->sp = (unsigned long) frame; |
| regs->ip = (unsigned long) ksig->ka.sa.sa_handler; |
| |
| /* We use the x32 calling convention here... */ |
| regs->di = ksig->sig; |
| regs->si = (unsigned long) &frame->info; |
| regs->dx = (unsigned long) &frame->uc; |
| |
| loadsegment(ds, __USER_DS); |
| loadsegment(es, __USER_DS); |
| |
| regs->cs = __USER_CS; |
| regs->ss = __USER_DS; |
| #endif /* CONFIG_X86_X32_ABI */ |
| |
| return 0; |
| } |
| |
| /* |
| * Do a signal return; undo the signal stack. |
| */ |
| #ifdef CONFIG_X86_32 |
| asmlinkage unsigned long sys_sigreturn(void) |
| { |
| struct pt_regs *regs = current_pt_regs(); |
| struct sigframe __user *frame; |
| sigset_t set; |
| |
| frame = (struct sigframe __user *)(regs->sp - 8); |
| |
| if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) |
| goto badframe; |
| if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1 |
| && __copy_from_user(&set.sig[1], &frame->extramask, |
| sizeof(frame->extramask)))) |
| goto badframe; |
| |
| set_current_blocked(&set); |
| |
| /* |
| * x86_32 has no uc_flags bits relevant to restore_sigcontext. |
| * Save a few cycles by skipping the __get_user. |
| */ |
| if (restore_sigcontext(regs, &frame->sc, 0)) |
| goto badframe; |
| return regs->ax; |
| |
| badframe: |
| signal_fault(regs, frame, "sigreturn"); |
| |
| return 0; |
| } |
| #endif /* CONFIG_X86_32 */ |
| |
| asmlinkage long sys_rt_sigreturn(void) |
| { |
| struct pt_regs *regs = current_pt_regs(); |
| struct rt_sigframe __user *frame; |
| sigset_t set; |
| unsigned long uc_flags; |
| |
| frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long)); |
| if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) |
| goto badframe; |
| if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) |
| goto badframe; |
| if (__get_user(uc_flags, &frame->uc.uc_flags)) |
| goto badframe; |
| |
| set_current_blocked(&set); |
| |
| if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) |
| goto badframe; |
| |
| if (restore_altstack(&frame->uc.uc_stack)) |
| goto badframe; |
| |
| return regs->ax; |
| |
| badframe: |
| signal_fault(regs, frame, "rt_sigreturn"); |
| return 0; |
| } |
| |
| static inline int is_ia32_compat_frame(struct ksignal *ksig) |
| { |
| return IS_ENABLED(CONFIG_IA32_EMULATION) && |
| ksig->ka.sa.sa_flags & SA_IA32_ABI; |
| } |
| |
| static inline int is_ia32_frame(struct ksignal *ksig) |
| { |
| return IS_ENABLED(CONFIG_X86_32) || is_ia32_compat_frame(ksig); |
| } |
| |
| static inline int is_x32_frame(struct ksignal *ksig) |
| { |
| return IS_ENABLED(CONFIG_X86_X32_ABI) && |
| ksig->ka.sa.sa_flags & SA_X32_ABI; |
| } |
| |
| static int |
| setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) |
| { |
| int usig = ksig->sig; |
| sigset_t *set = sigmask_to_save(); |
| compat_sigset_t *cset = (compat_sigset_t *) set; |
| |
| /* Set up the stack frame */ |
| if (is_ia32_frame(ksig)) { |
| if (ksig->ka.sa.sa_flags & SA_SIGINFO) |
| return ia32_setup_rt_frame(usig, ksig, cset, regs); |
| else |
| return ia32_setup_frame(usig, ksig, cset, regs); |
| } else if (is_x32_frame(ksig)) { |
| return x32_setup_rt_frame(ksig, cset, regs); |
| } else { |
| return __setup_rt_frame(ksig->sig, ksig, set, regs); |
| } |
| } |
| |
| static void |
| handle_signal(struct ksignal *ksig, struct pt_regs *regs) |
| { |
| bool stepping, failed; |
| struct fpu *fpu = ¤t->thread.fpu; |
| |
| if (v8086_mode(regs)) |
| save_v86_state((struct kernel_vm86_regs *) regs, VM86_SIGNAL); |
| |
| /* Are we from a system call? */ |
| if (syscall_get_nr(current, regs) >= 0) { |
| /* If so, check system call restarting.. */ |
| switch (syscall_get_error(current, regs)) { |
| case -ERESTART_RESTARTBLOCK: |
| case -ERESTARTNOHAND: |
| regs->ax = -EINTR; |
| break; |
| |
| case -ERESTARTSYS: |
| if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { |
| regs->ax = -EINTR; |
| break; |
| } |
| /* fallthrough */ |
| case -ERESTARTNOINTR: |
| regs->ax = regs->orig_ax; |
| regs->ip -= 2; |
| break; |
| } |
| } |
| |
| /* |
| * If TF is set due to a debugger (TIF_FORCED_TF), clear TF now |
| * so that register information in the sigcontext is correct and |
| * then notify the tracer before entering the signal handler. |
| */ |
| stepping = test_thread_flag(TIF_SINGLESTEP); |
| if (stepping) |
| user_disable_single_step(current); |
| |
| failed = (setup_rt_frame(ksig, regs) < 0); |
| if (!failed) { |
| /* |
| * Clear the direction flag as per the ABI for function entry. |
| * |
| * Clear RF when entering the signal handler, because |
| * it might disable possible debug exception from the |
| * signal handler. |
| * |
| * Clear TF for the case when it wasn't set by debugger to |
| * avoid the recursive send_sigtrap() in SIGTRAP handler. |
| */ |
| regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF); |
| /* |
| * Ensure the signal handler starts with the new fpu state. |
| */ |
| if (fpu->fpstate_active) |
| fpu__clear(fpu); |
| } |
| signal_setup_done(failed, ksig, stepping); |
| } |
| |
| static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs) |
| { |
| /* |
| * This function is fundamentally broken as currently |
| * implemented. |
| * |
| * The idea is that we want to trigger a call to the |
| * restart_block() syscall and that we want in_ia32_syscall(), |
| * in_x32_syscall(), etc. to match whatever they were in the |
| * syscall being restarted. We assume that the syscall |
| * instruction at (regs->ip - 2) matches whatever syscall |
| * instruction we used to enter in the first place. |
| * |
| * The problem is that we can get here when ptrace pokes |
| * syscall-like values into regs even if we're not in a syscall |
| * at all. |
| * |
| * For now, we maintain historical behavior and guess based on |
| * stored state. We could do better by saving the actual |
| * syscall arch in restart_block or (with caveats on x32) by |
| * checking if regs->ip points to 'int $0x80'. The current |
| * behavior is incorrect if a tracer has a different bitness |
| * than the tracee. |
| */ |
| #ifdef CONFIG_IA32_EMULATION |
| if (current_thread_info()->status & (TS_COMPAT|TS_I386_REGS_POKED)) |
| return __NR_ia32_restart_syscall; |
| #endif |
| #ifdef CONFIG_X86_X32_ABI |
| return __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT); |
| #else |
| return __NR_restart_syscall; |
| #endif |
| } |
| |
| /* |
| * 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. |
| */ |
| void do_signal(struct pt_regs *regs) |
| { |
| struct ksignal ksig; |
| |
| if (get_signal(&ksig)) { |
| /* Whee! Actually deliver the signal. */ |
| handle_signal(&ksig, regs); |
| return; |
| } |
| |
| /* Did we come from a system call? */ |
| if (syscall_get_nr(current, regs) >= 0) { |
| /* Restart the system call - no handlers present */ |
| switch (syscall_get_error(current, regs)) { |
| case -ERESTARTNOHAND: |
| case -ERESTARTSYS: |
| case -ERESTARTNOINTR: |
| regs->ax = regs->orig_ax; |
| regs->ip -= 2; |
| break; |
| |
| case -ERESTART_RESTARTBLOCK: |
| regs->ax = get_nr_restart_syscall(regs); |
| regs->ip -= 2; |
| break; |
| } |
| } |
| |
| /* |
| * If there's no signal to deliver, we just put the saved sigmask |
| * back. |
| */ |
| restore_saved_sigmask(); |
| } |
| |
| void signal_fault(struct pt_regs *regs, void __user *frame, char *where) |
| { |
| struct task_struct *me = current; |
| |
| if (show_unhandled_signals && printk_ratelimit()) { |
| printk("%s" |
| "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx", |
| task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG, |
| me->comm, me->pid, where, frame, |
| regs->ip, regs->sp, regs->orig_ax); |
| print_vma_addr(" in ", regs->ip); |
| pr_cont("\n"); |
| } |
| |
| force_sig(SIGSEGV, me); |
| } |
| |
| #ifdef CONFIG_X86_X32_ABI |
| asmlinkage long sys32_x32_rt_sigreturn(void) |
| { |
| struct pt_regs *regs = current_pt_regs(); |
| struct rt_sigframe_x32 __user *frame; |
| sigset_t set; |
| unsigned long uc_flags; |
| |
| frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8); |
| |
| if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) |
| goto badframe; |
| if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) |
| goto badframe; |
| if (__get_user(uc_flags, &frame->uc.uc_flags)) |
| goto badframe; |
| |
| set_current_blocked(&set); |
| |
| if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) |
| goto badframe; |
| |
| if (compat_restore_altstack(&frame->uc.uc_stack)) |
| goto badframe; |
| |
| return regs->ax; |
| |
| badframe: |
| signal_fault(regs, frame, "x32 rt_sigreturn"); |
| return 0; |
| } |
| #endif |