1 /* 2 * Copyright (c) 1999-2000 Wichert Akkerman <wichert (at) cistron.nl> 3 * Copyright (c) 2002-2005 Roland McGrath <roland (at) redhat.com> 4 * Copyright (c) 2008 Jan Kratochvil <jan.kratochvil (at) redhat.com> 5 * Copyright (c) 2009-2013 Denys Vlasenko <dvlasenk (at) redhat.com> 6 * Copyright (c) 2006-2015 Dmitry V. Levin <ldv (at) altlinux.org> 7 * Copyright (c) 2014-2017 The strace developers. 8 * All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #include "defs.h" 34 #include <sched.h> 35 #include <asm/unistd.h> 36 37 #ifndef CSIGNAL 38 # define CSIGNAL 0x000000ff 39 #endif 40 41 #include "xlat/clone_flags.h" 42 #include "xlat/setns_types.h" 43 #include "xlat/unshare_flags.h" 44 45 #if defined IA64 46 # define ARG_FLAGS 0 47 # define ARG_STACK 1 48 # define ARG_STACKSIZE (tcp->scno == __NR_clone2 ? 2 : -1) 49 # define ARG_PTID (tcp->scno == __NR_clone2 ? 3 : 2) 50 # define ARG_CTID (tcp->scno == __NR_clone2 ? 4 : 3) 51 # define ARG_TLS (tcp->scno == __NR_clone2 ? 5 : 4) 52 #elif defined S390 || defined S390X || defined CRISV10 || defined CRISV32 53 # define ARG_STACK 0 54 # define ARG_FLAGS 1 55 # define ARG_PTID 2 56 # define ARG_CTID 3 57 # define ARG_TLS 4 58 #elif defined X86_64 || defined X32 59 /* x86 personality processes have the last two arguments flipped. */ 60 # define ARG_FLAGS 0 61 # define ARG_STACK 1 62 # define ARG_PTID 2 63 # define ARG_CTID ((current_personality != 1) ? 3 : 4) 64 # define ARG_TLS ((current_personality != 1) ? 4 : 3) 65 #elif defined ALPHA || defined TILE || defined OR1K || defined RISCV 66 # define ARG_FLAGS 0 67 # define ARG_STACK 1 68 # define ARG_PTID 2 69 # define ARG_CTID 3 70 # define ARG_TLS 4 71 #else 72 # define ARG_FLAGS 0 73 # define ARG_STACK 1 74 # define ARG_PTID 2 75 # define ARG_TLS 3 76 # define ARG_CTID 4 77 #endif 78 79 static void 80 print_tls_arg(struct tcb *const tcp, const kernel_ulong_t addr) 81 { 82 #ifdef HAVE_STRUCT_USER_DESC 83 # if SUPPORTED_PERSONALITIES > 1 84 if (current_personality == 1) 85 # endif 86 { 87 print_user_desc(tcp, tcp->u_arg[ARG_TLS]); 88 } 89 # if SUPPORTED_PERSONALITIES > 1 90 else 91 # endif 92 #endif /* HAVE_STRUCT_USER_DESC */ 93 { 94 printaddr(tcp->u_arg[ARG_TLS]); 95 } 96 } 97 98 SYS_FUNC(clone) 99 { 100 if (exiting(tcp)) { 101 const char *sep = "|"; 102 kernel_ulong_t flags = tcp->u_arg[ARG_FLAGS]; 103 tprints("child_stack="); 104 printaddr(tcp->u_arg[ARG_STACK]); 105 tprints(", "); 106 #ifdef ARG_STACKSIZE 107 if (ARG_STACKSIZE != -1) 108 tprintf("stack_size=%#" PRI_klx ", ", 109 tcp->u_arg[ARG_STACKSIZE]); 110 #endif 111 tprints("flags="); 112 if (!printflags64(clone_flags, flags & ~CSIGNAL, NULL)) 113 sep = ""; 114 if ((flags & CSIGNAL) != 0) 115 tprintf("%s%s", sep, signame(flags & CSIGNAL)); 116 if ((flags & (CLONE_PARENT_SETTID|CLONE_CHILD_SETTID 117 |CLONE_CHILD_CLEARTID|CLONE_SETTLS)) == 0) 118 return 0; 119 if (flags & CLONE_PARENT_SETTID) { 120 tprints(", parent_tidptr="); 121 printaddr(tcp->u_arg[ARG_PTID]); 122 } 123 if (flags & CLONE_SETTLS) { 124 tprints(", tls="); 125 print_tls_arg(tcp, tcp->u_arg[ARG_TLS]); 126 } 127 if (flags & (CLONE_CHILD_SETTID|CLONE_CHILD_CLEARTID)) { 128 tprints(", child_tidptr="); 129 printaddr(tcp->u_arg[ARG_CTID]); 130 } 131 } 132 /* TODO on syscall entry: 133 * We can clear CLONE_PTRACE here since it is an ancient hack 134 * to allow us to catch children, and we use another hack for that. 135 * But CLONE_PTRACE can conceivably be used by malicious programs 136 * to subvert us. By clearing this bit, we can defend against it: 137 * in untraced execution, CLONE_PTRACE should have no effect. 138 * 139 * We can also clear CLONE_UNTRACED, since it allows to start 140 * children outside of our control. At the moment 141 * I'm trying to figure out whether there is a *legitimate* 142 * use of this flag which we should respect. 143 */ 144 return 0; 145 } 146 147 SYS_FUNC(setns) 148 { 149 printfd(tcp, tcp->u_arg[0]); 150 tprints(", "); 151 printxval(setns_types, tcp->u_arg[1], "CLONE_NEW???"); 152 153 return RVAL_DECODED; 154 } 155 156 SYS_FUNC(unshare) 157 { 158 printflags64(unshare_flags, tcp->u_arg[0], "CLONE_???"); 159 return RVAL_DECODED; 160 } 161 162 SYS_FUNC(fork) 163 { 164 return RVAL_DECODED | RVAL_UDECIMAL; 165 } 166
