ptrace.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  4 */
  5
  6#include <linux/audit.h>
  7#include <linux/ptrace.h>
  8#include <linux/sched.h>
  9#include <linux/uaccess.h>
 10#include <asm/ptrace-abi.h>
 11
 12#define CREATE_TRACE_POINTS
 13#include <trace/events/syscalls.h>
 14
 15void user_enable_single_step(struct task_struct *child)
 16{
 17	set_tsk_thread_flag(child, TIF_SINGLESTEP);
 18
 19#ifdef SUBARCH_SET_SINGLESTEPPING
 20	SUBARCH_SET_SINGLESTEPPING(child, 1);
 21#endif
 22}
 23
 24void user_disable_single_step(struct task_struct *child)
 25{
 26	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
 27
 28#ifdef SUBARCH_SET_SINGLESTEPPING
 29	SUBARCH_SET_SINGLESTEPPING(child, 0);
 30#endif
 31}
 32
 33/*
 34 * Called by kernel/ptrace.c when detaching..
 35 */
 36void ptrace_disable(struct task_struct *child)
 37{
 38	user_disable_single_step(child);
 39}
 40
 41long arch_ptrace(struct task_struct *child, long request,
 42		 unsigned long addr, unsigned long data)
 43{
 44	int i, ret;
 45	unsigned long __user *p = (void __user *)data;
 46	void __user *vp = p;
 47
 48	switch (request) {
 49	/* read the word at location addr in the USER area. */
 50	case PTRACE_PEEKUSR:
 51		ret = peek_user(child, addr, data);
 52		break;
 53
 54	/* write the word at location addr in the USER area */
 55	case PTRACE_POKEUSR:
 56		ret = poke_user(child, addr, data);
 57		break;
 58
 59	case PTRACE_SYSEMU:
 60	case PTRACE_SYSEMU_SINGLESTEP:
 61		ret = -EIO;
 62		break;
 63
 64#ifdef PTRACE_GETREGS
 65	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 66		if (!access_ok(p, MAX_REG_OFFSET)) {
 67			ret = -EIO;
 68			break;
 69		}
 70		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 71			__put_user(getreg(child, i), p);
 72			p++;
 73		}
 74		ret = 0;
 75		break;
 76	}
 77#endif
 78#ifdef PTRACE_SETREGS
 79	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 80		unsigned long tmp = 0;
 81		if (!access_ok(p, MAX_REG_OFFSET)) {
 82			ret = -EIO;
 83			break;
 84		}
 85		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 86			__get_user(tmp, p);
 87			putreg(child, i, tmp);
 88			p++;
 89		}
 90		ret = 0;
 91		break;
 92	}
 93#endif
 94	case PTRACE_GET_THREAD_AREA:
 95		ret = ptrace_get_thread_area(child, addr, vp);
 96		break;
 97
 98	case PTRACE_SET_THREAD_AREA:
 99		ret = ptrace_set_thread_area(child, addr, vp);
100		break;
101
102	default:
103		ret = ptrace_request(child, request, addr, data);
104		if (ret == -EIO)
105			ret = subarch_ptrace(child, request, addr, data);
106		break;
107	}
108
109	return ret;
110}
111
112static void send_sigtrap(struct uml_pt_regs *regs, int error_code)
113{
114	/* Send us the fake SIGTRAP */
115	force_sig_fault(SIGTRAP, TRAP_BRKPT,
116			/* User-mode eip? */
117			UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL);
118}
119
120/*
121 * XXX Check TIF_SINGLESTEP for singlestepping check and
122 * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
123 */
124int syscall_trace_enter(struct pt_regs *regs)
125{
126	audit_syscall_entry(UPT_SYSCALL_NR(&regs->regs),
127			    UPT_SYSCALL_ARG1(&regs->regs),
128			    UPT_SYSCALL_ARG2(&regs->regs),
129			    UPT_SYSCALL_ARG3(&regs->regs),
130			    UPT_SYSCALL_ARG4(&regs->regs));
131
132	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
133		trace_sys_enter(regs, UPT_SYSCALL_NR(&regs->regs));
134
135	if (!test_thread_flag(TIF_SYSCALL_TRACE))
136		return 0;
137
138	return ptrace_report_syscall_entry(regs);
139}
140
141void syscall_trace_leave(struct pt_regs *regs)
142{
143	int ptraced = current->ptrace;
144
145	audit_syscall_exit(regs);
146
147	/* Fake a debug trap */
148	if (test_thread_flag(TIF_SINGLESTEP))
149		send_sigtrap(&regs->regs, 0);
150
151	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
152		trace_sys_exit(regs, PT_REGS_SYSCALL_RET(regs));
153
154	if (!test_thread_flag(TIF_SYSCALL_TRACE))
155		return;
156
157	ptrace_report_syscall_exit(regs, 0);
158	/* force do_signal() --> is_syscall() */
159	if (ptraced & PT_PTRACED)
160		set_thread_flag(TIF_SIGPENDING);
161}