From 24e6dc35ccd825de7c71751610ff8f3295347e5b Mon Sep 17 00:00:00 2001 From: Brian Gerst Date: Mon, 6 Jun 2022 16:38:01 -0400 Subject: x86/signal/32: Merge native and compat 32-bit signal code There are significant differences between signal handling on 32-bit vs. 64-bit, like different structure layouts and legacy syscalls. Instead of duplicating that code for native and compat, merge both versions into one file. Signed-off-by: Brian Gerst Signed-off-by: Borislav Petkov Acked-by: "Eric W. Biederman" Link: https://lore.kernel.org/r/20220606203802.158958-8-brgerst@gmail.com Signed-off-by: Borislav Petkov --- arch/x86/ia32/Makefile | 2 - arch/x86/ia32/ia32_signal.c | 340 -------------------------------------------- 2 files changed, 342 deletions(-) delete mode 100644 arch/x86/ia32/ia32_signal.c (limited to 'arch/x86/ia32') diff --git a/arch/x86/ia32/Makefile b/arch/x86/ia32/Makefile index e481056698de..333556a86b2a 100644 --- a/arch/x86/ia32/Makefile +++ b/arch/x86/ia32/Makefile @@ -3,7 +3,5 @@ # Makefile for the ia32 kernel emulation subsystem. # -obj-$(CONFIG_IA32_EMULATION) := ia32_signal.o - audit-class-$(CONFIG_AUDIT) := audit.o obj-$(CONFIG_IA32_EMULATION) += $(audit-class-y) diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c deleted file mode 100644 index e28421f53d44..000000000000 --- a/arch/x86/ia32/ia32_signal.c +++ /dev/null @@ -1,340 +0,0 @@ -// 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 -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -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) - -int ia32_setup_frame(struct ksignal *ksig, struct pt_regs *regs) -{ - compat_sigset_t *set = (compat_sigset_t *) sigmask_to_save(); - 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(ksig->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 = ksig->sig; - regs->dx = 0; - regs->cx = 0; - - loadsegment(ds, __USER_DS); - loadsegment(es, __USER_DS); - - regs->cs = __USER32_CS; - regs->ss = __USER_DS; - - return 0; -Efault: - user_access_end(); - return -EFAULT; -} - -int ia32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) -{ - compat_sigset_t *set = (compat_sigset_t *) sigmask_to_save(); - 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(ksig->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 = ksig->sig; - regs->dx = (unsigned long) &frame->info; - regs->cx = (unsigned long) &frame->uc; - - loadsegment(ds, __USER_DS); - loadsegment(es, __USER_DS); - - regs->cs = __USER32_CS; - regs->ss = __USER_DS; - - return 0; -Efault: - user_access_end(); - return -EFAULT; -} -- cgit v1.2.3