/* * Copyright (c) 2002 Andi Kleen <ak@suse.de> * Copyright (c) 2002 Michal Ludvig <mludvig@suse.cz> * Copyright (c) 2002 Roland McGrath <roland@redhat.com> * Copyright (c) 2008-2013 Denys Vlasenko <vda.linux@googlemail.com> * Copyright (c) 2012 H.J. Lu <hongjiu.lu@intel.com> * Copyright (c) 2010-2015 Dmitry V. Levin <ldv@altlinux.org> * Copyright (c) 2015-2018 The strace developers. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifdef X86_64 # define X32_PERSONALITY_NUMBER 2 #else # define X32_PERSONALITY_NUMBER 0 #endif /* Return codes: 1 - ok, 0 - ignore, other - error. */ static int arch_get_scno(struct tcb *tcp) { kernel_ulong_t scno = 0; unsigned int currpers; #ifndef __X32_SYSCALL_BIT # define __X32_SYSCALL_BIT 0x40000000 #endif #if 1 /* * GETREGSET of NT_PRSTATUS tells us regset size, * which unambiguously detects i386. * * Linux kernel distinguishes x86-64 and x32 processes * solely by looking at __X32_SYSCALL_BIT: * arch/x86/include/asm/compat.h::is_x32_task(): * if (task_pt_regs(current)->orig_ax & __X32_SYSCALL_BIT) * return true; */ if (x86_io.iov_len == sizeof(i386_regs)) { scno = i386_regs.orig_eax; currpers = 1; } else { scno = x86_64_regs.orig_rax; currpers = 0; if (scno & __X32_SYSCALL_BIT) { /* * Syscall number -1 requires special treatment: * it might be a side effect of SECCOMP_RET_ERRNO * filtering that sets orig_rax to -1 * in some versions of linux kernel. * If that is the case, then * __X32_SYSCALL_BIT logic does not apply. */ if ((long long) x86_64_regs.orig_rax != -1) { currpers = 2; } else { # ifdef X32 currpers = 2; # endif } } } #elif 0 /* * cs = 0x33 for long mode (native 64 bit and x32) * cs = 0x23 for compatibility mode (32 bit) * ds = 0x2b for x32 mode (x86-64 in 32 bit) */ scno = x86_64_regs.orig_rax; switch (x86_64_regs.cs) { case 0x23: currpers = 1; break; case 0x33: if (x86_64_regs.ds == 0x2b) { currpers = 2; } else currpers = 0; break; default: error_msg("Unknown value CS=0x%08X while " "detecting personality of process PID=%d", (int)x86_64_regs.cs, tcp->pid); currpers = current_personality; break; } #elif 0 /* * This version analyzes the opcode of a syscall instruction. * (int 0x80 on i386 vs. syscall on x86-64) * It works, but is too complicated, and strictly speaking, unreliable. */ unsigned long call, rip = x86_64_regs.rip; /* sizeof(syscall) == sizeof(int 0x80) == 2 */ rip -= 2; errno = 0; call = ptrace(PTRACE_PEEKTEXT, tcp->pid, (char *)rip, (char *)0); if (errno) perror_msg("ptrace_peektext failed"); switch (call & 0xffff) { /* x86-64: syscall = 0x0f 0x05 */ case 0x050f: currpers = 0; break; /* i386: int 0x80 = 0xcd 0x80 */ case 0x80cd: currpers = 1; break; default: currpers = current_personality; error_msg("Unknown syscall opcode (0x%04X) while " "detecting personality of process PID=%d", (int)call, tcp->pid); break; } #endif #ifdef X32 /* * If we are built for a x32 system, then personality 0 is x32 * (not x86_64), and stracing of x86_64 apps is not supported. * Stracing of i386 apps is still supported. */ if (currpers == 0) { error_msg("syscall_%" PRI_klu "(...) in unsupported " "64-bit mode of process PID=%d", scno, tcp->pid); return 0; } currpers &= ~2; /* map 2,1 to 0,1 */ #endif /* X32 */ update_personality(tcp, currpers); tcp->scno = scno; return 1; }