1 /*
2 * Copyright (c) 1999-2000 Wichert Akkerman <wichert@cistron.nl>
3 * Copyright (c) 2002-2005 Roland McGrath <roland@redhat.com>
4 * Copyright (c) 2008 Jan Kratochvil <jan.kratochvil@redhat.com>
5 * Copyright (c) 2009-2013 Denys Vlasenko <dvlasenk@redhat.com>
6 * Copyright (c) 2006-2015 Dmitry V. Levin <ldv@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
print_tls_arg(struct tcb * const tcp,const kernel_ulong_t addr)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
SYS_FUNC(clone)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
SYS_FUNC(setns)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
SYS_FUNC(unshare)156 SYS_FUNC(unshare)
157 {
158 printflags64(unshare_flags, tcp->u_arg[0], "CLONE_???");
159 return RVAL_DECODED;
160 }
161
SYS_FUNC(fork)162 SYS_FUNC(fork)
163 {
164 return RVAL_DECODED | RVAL_UDECIMAL;
165 }
166