1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
|
/*
* Copyright (C) 2000-2003, Axis Communications AB.
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/signal.h>
#include <linux/security.h>
#include <asm/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
/*
* Determines which bits in DCCR the user has access to.
* 1 = access, 0 = no access.
*/
#define DCCR_MASK 0x0000001f /* XNZVC */
/*
* Get contents of register REGNO in task TASK.
*/
inline long get_reg(struct task_struct *task, unsigned int regno)
{
/* USP is a special case, it's not in the pt_regs struct but
* in the tasks thread struct
*/
if (regno == PT_USP)
return task->thread.usp;
else if (regno < PT_MAX)
return ((unsigned long *)task_pt_regs(task))[regno];
else
return 0;
}
/*
* Write contents of register REGNO in task TASK.
*/
inline int put_reg(struct task_struct *task, unsigned int regno,
unsigned long data)
{
if (regno == PT_USP)
task->thread.usp = data;
else if (regno < PT_MAX)
((unsigned long *)task_pt_regs(task))[regno] = data;
else
return -1;
return 0;
}
/*
* Called by kernel/ptrace.c when detaching.
*
* Make sure the single step bit is not set.
*/
void
ptrace_disable(struct task_struct *child)
{
/* Todo - pending singlesteps? */
}
/*
* Note that this implementation of ptrace behaves differently from vanilla
* ptrace. Contrary to what the man page says, in the PTRACE_PEEKTEXT,
* PTRACE_PEEKDATA, and PTRACE_PEEKUSER requests the data variable is not
* ignored. Instead, the data variable is expected to point at a location
* (in user space) where the result of the ptrace call is written (instead of
* being returned).
*/
long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
int ret;
unsigned long __user *datap = (unsigned long __user *)data;
switch (request) {
/* Read word at location address. */
case PTRACE_PEEKTEXT:
case PTRACE_PEEKDATA:
ret = generic_ptrace_peekdata(child, addr, data);
break;
/* Read the word at location address in the USER area. */
case PTRACE_PEEKUSR: {
unsigned long tmp;
ret = -EIO;
if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
break;
tmp = get_reg(child, addr >> 2);
ret = put_user(tmp, datap);
break;
}
/* Write the word at location address. */
case PTRACE_POKETEXT:
case PTRACE_POKEDATA:
ret = 0;
if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
break;
ret = -EIO;
break;
/* Write the word at location address in the USER area. */
case PTRACE_POKEUSR:
ret = -EIO;
if ((addr & 3) || addr < 0 || addr > PT_MAX << 2)
break;
addr >>= 2;
if (addr == PT_DCCR) {
/* don't allow the tracing process to change stuff like
* interrupt enable, kernel/user bit, dma enables etc.
*/
data &= DCCR_MASK;
data |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
}
if (put_reg(child, addr, data))
break;
ret = 0;
break;
case PTRACE_SYSCALL:
case PTRACE_CONT:
ret = -EIO;
if (!valid_signal(data))
break;
if (request == PTRACE_SYSCALL) {
set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
}
else {
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
}
child->exit_code = data;
/* TODO: make sure any pending breakpoint is killed */
wake_up_process(child);
ret = 0;
break;
/* Make the child exit by sending it a sigkill. */
case PTRACE_KILL:
ret = 0;
if (child->exit_state == EXIT_ZOMBIE)
break;
child->exit_code = SIGKILL;
/* TODO: make sure any pending breakpoint is killed */
wake_up_process(child);
break;
/* Set the trap flag. */
case PTRACE_SINGLESTEP:
ret = -EIO;
if (!valid_signal(data))
break;
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
/* TODO: set some clever breakpoint mechanism... */
child->exit_code = data;
wake_up_process(child);
ret = 0;
break;
case PTRACE_DETACH:
ret = ptrace_detach(child, data);
break;
/* Get all GP registers from the child. */
case PTRACE_GETREGS: {
int i;
unsigned long tmp;
ret = 0;
for (i = 0; i <= PT_MAX; i++) {
tmp = get_reg(child, i);
if (put_user(tmp, datap)) {
ret = -EFAULT;
break;
}
data += sizeof(long);
}
break;
}
/* Set all GP registers in the child. */
case PTRACE_SETREGS: {
int i;
unsigned long tmp;
ret = 0;
for (i = 0; i <= PT_MAX; i++) {
if (get_user(tmp, datap)) {
ret = -EFAULT;
break;
}
if (i == PT_DCCR) {
tmp &= DCCR_MASK;
tmp |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
}
put_reg(child, i, tmp);
data += sizeof(long);
}
break;
}
default:
ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}
void do_syscall_trace(void)
{
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
if (!(current->ptrace & PT_PTRACED))
return;
/* the 0x80 provides a way for the tracing parent to distinguish
between a syscall stop and SIGTRAP delivery */
ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
? 0x80 : 0));
/*
* This isn't the same as continuing with a signal, but it will do for
* normal use.
*/
if (current->exit_code) {
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
}
}
|
