Branch data Line data Source code
1 : : /*
2 : : * Copyright (c) 2002 Andi Kleen <ak@suse.de>
3 : : * Copyright (c) 2002 Michal Ludvig <mludvig@suse.cz>
4 : : * Copyright (c) 2002 Roland McGrath <roland@redhat.com>
5 : : * Copyright (c) 2008-2013 Denys Vlasenko <vda.linux@googlemail.com>
6 : : * Copyright (c) 2012 H.J. Lu <hongjiu.lu@intel.com>
7 : : * Copyright (c) 2010-2015 Dmitry V. Levin <ldv@altlinux.org>
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 : : #ifdef X86_64
34 : : # define X32_PERSONALITY_NUMBER 2
35 : : #else
36 : : # define X32_PERSONALITY_NUMBER 0
37 : : #endif
38 : :
39 : : /* Return codes: 1 - ok, 0 - ignore, other - error. */
40 : : static int
41 : 11667255 : arch_get_scno(struct tcb *tcp)
42 : : {
43 : 11667255 : kernel_ulong_t scno = 0;
44 : : unsigned int currpers;
45 : :
46 : : #ifndef __X32_SYSCALL_BIT
47 : : # define __X32_SYSCALL_BIT 0x40000000
48 : : #endif
49 : :
50 : : #if 1
51 : : /*
52 : : * GETREGSET of NT_PRSTATUS tells us regset size,
53 : : * which unambiguously detects i386.
54 : : *
55 : : * Linux kernel distinguishes x86-64 and x32 processes
56 : : * solely by looking at __X32_SYSCALL_BIT:
57 : : * arch/x86/include/asm/compat.h::is_x32_task():
58 : : * if (task_pt_regs(current)->orig_ax & __X32_SYSCALL_BIT)
59 : : * return true;
60 : : */
61 [ + + ]: 11667255 : if (x86_io.iov_len == sizeof(i386_regs)) {
62 : 103356 : scno = i386_regs.orig_eax;
63 : 103356 : currpers = 1;
64 : : } else {
65 : 11563899 : scno = x86_64_regs.orig_rax;
66 : 11563899 : currpers = 0;
67 [ + + ]: 11563899 : if (scno & __X32_SYSCALL_BIT) {
68 : : /*
69 : : * Syscall number -1 requires special treatment:
70 : : * it might be a side effect of SECCOMP_RET_ERRNO
71 : : * filtering that sets orig_rax to -1
72 : : * in some versions of linux kernel.
73 : : * If that is the case, then
74 : : * __X32_SYSCALL_BIT logic does not apply.
75 : : */
76 [ + - ]: 5 : if ((long long) x86_64_regs.orig_rax != -1) {
77 : 5 : scno -= __X32_SYSCALL_BIT;
78 : 5 : currpers = 2;
79 : : } else {
80 : : # ifdef X32
81 : : currpers = 2;
82 : : # endif
83 : : }
84 : : }
85 : : }
86 : :
87 : : #elif 0
88 : : /*
89 : : * cs = 0x33 for long mode (native 64 bit and x32)
90 : : * cs = 0x23 for compatibility mode (32 bit)
91 : : * ds = 0x2b for x32 mode (x86-64 in 32 bit)
92 : : */
93 : : scno = x86_64_regs.orig_rax;
94 : : switch (x86_64_regs.cs) {
95 : : case 0x23: currpers = 1; break;
96 : : case 0x33:
97 : : if (x86_64_regs.ds == 0x2b) {
98 : : currpers = 2;
99 : : scno &= ~__X32_SYSCALL_BIT;
100 : : } else
101 : : currpers = 0;
102 : : break;
103 : : default:
104 : : error_msg("Unknown value CS=0x%08X while "
105 : : "detecting personality of process PID=%d",
106 : : (int)x86_64_regs.cs, tcp->pid);
107 : : currpers = current_personality;
108 : : break;
109 : : }
110 : : #elif 0
111 : : /*
112 : : * This version analyzes the opcode of a syscall instruction.
113 : : * (int 0x80 on i386 vs. syscall on x86-64)
114 : : * It works, but is too complicated, and strictly speaking, unreliable.
115 : : */
116 : : unsigned long call, rip = x86_64_regs.rip;
117 : : /* sizeof(syscall) == sizeof(int 0x80) == 2 */
118 : : rip -= 2;
119 : : errno = 0;
120 : : call = ptrace(PTRACE_PEEKTEXT, tcp->pid, (char *)rip, (char *)0);
121 : : if (errno)
122 : : perror_msg("ptrace_peektext failed");
123 : : switch (call & 0xffff) {
124 : : /* x86-64: syscall = 0x0f 0x05 */
125 : : case 0x050f: currpers = 0; break;
126 : : /* i386: int 0x80 = 0xcd 0x80 */
127 : : case 0x80cd: currpers = 1; break;
128 : : default:
129 : : currpers = current_personality;
130 : : error_msg("Unknown syscall opcode (0x%04X) while "
131 : : "detecting personality of process PID=%d",
132 : : (int)call, tcp->pid);
133 : : break;
134 : : }
135 : : #endif
136 : :
137 : : #ifdef X32
138 : : /*
139 : : * If we are built for a x32 system, then personality 0 is x32
140 : : * (not x86_64), and stracing of x86_64 apps is not supported.
141 : : * Stracing of i386 apps is still supported.
142 : : */
143 : : if (currpers == 0) {
144 : : error_msg("syscall_%" PRI_klu "(...) in unsupported "
145 : : "64-bit mode of process PID=%d", scno, tcp->pid);
146 : : return 0;
147 : : }
148 : : currpers &= ~2; /* map 2,1 to 0,1 */
149 : : #endif /* X32 */
150 : :
151 : 11667255 : update_personality(tcp, currpers);
152 : 11667255 : tcp->scno = scno;
153 : 11667255 : return 1;
154 : : }
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