1/* $NetBSD$ */ 2 3/*- 4 * Copyright (c) 2011 Reinoud Zandijk <reinoud@NetBSD.org> 5 * Copyright (c) 2012 Jared D. McNeill <jmcneill@invisible.ca> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 18 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 19 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 20 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 21 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 25 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 27 * POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30#include <sys/cdefs.h> 31__KERNEL_RCSID(0, "$NetBSD$"); 32 33#include <sys/param.h> 34#include <sys/proc.h> 35#include <sys/systm.h> 36 37#include <machine/userret.h> 38 39#include "syscallemu.h" 40 41/* 42 * If syscallemu specific data is present for the process, verify that the 43 * caller is allowed to execute system calls. If not, deliver a SIGILL to 44 * the process. When syscallemu specific data is not present, simply defer 45 * to the original syscall handler. 46 */ 47static void 48x86_syscall_emu(struct trapframe *frame) 49{ 50 void (*md_syscall)(struct trapframe *) = NULL; 51 struct syscallemu_data *sce; 52 register_t rip_call; 53 struct proc *p; 54 ksiginfo_t ksi; 55 lwp_t *l; 56 57 l = curlwp; 58 p = l->l_proc; 59 60 rip_call = X86_TF_RIP(frame) - frame->tf_err; 61 62 /* Determine if we need to emulate the system call */ 63 sce = syscallemu_getsce(p); 64 if (sce) { 65 if ((rip_call >= sce->sce_user_start && 66 rip_call < sce->sce_user_end) || 67 (rip_call + frame->tf_err >= sce->sce_user_start && 68 rip_call + frame->tf_err < sce->sce_user_end)) { 69 md_syscall = NULL; 70 } else { 71 md_syscall = sce->sce_md_syscall; 72 } 73 } else { 74 md_syscall = p->p_md.md_syscall; 75 } 76 77 if (md_syscall == NULL) { 78 /* If emulating, deliver SIGILL to process */ 79 X86_TF_RIP(frame) = rip_call; 80 KSI_INIT_TRAP(&ksi); 81 ksi.ksi_signo = SIGILL; 82 ksi.ksi_code = ILL_ILLTRP; 83 ksi.ksi_addr = (void *)X86_TF_RIP(frame); 84 ksi.ksi_trap = 0; 85 trapsignal(l, &ksi); 86 userret(l); 87 } else { 88 /* Not emulating, so treat as a normal syscall */ 89 KASSERT(md_syscall != NULL); 90 md_syscall(frame); 91 } 92} 93 94/* 95 * Set p_md.md_syscall to our syscall filter, and return a pointer to the 96 * original syscall handler. 97 */ 98void * 99md_syscallemu(struct proc *p) 100{ 101 void *osyscall; 102 103 osyscall = p->p_md.md_syscall; 104 p->p_md.md_syscall = x86_syscall_emu; 105 106 return osyscall; 107} 108