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1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2020 Cyril Hrubis <chrbis@suse.cz>
4  *
5  * After fix for CVE-2018-1000199 (see ptrace08.c) subsequent calls to POKEUSER
6  * for x86 debug registers were ignored silently.
7  *
8  * This is a regression test for commit:
9  *
10  * commit bd14406b78e6daa1ea3c1673bda1ffc9efdeead0
11  * Author: Jiri Olsa <jolsa@kernel.org>
12  * Date:   Mon Aug 27 11:12:25 2018 +0200
13  *
14  *     perf/hw_breakpoint: Modify breakpoint even if the new attr has disabled set
15  */
16 
17 #include <stdlib.h>
18 #include <stdio.h>
19 #include <stddef.h>
20 #include <sys/ptrace.h>
21 #include <sys/user.h>
22 #include <signal.h>
23 #include "tst_test.h"
24 
25 static pid_t child_pid;
26 
child_main(void)27 static void child_main(void)
28 {
29 	raise(SIGSTOP);
30 	exit(0);
31 }
32 
run(void)33 static void run(void)
34 {
35 	int status;
36 	unsigned long addr;
37 
38 	child_pid = SAFE_FORK();
39 
40 	if (!child_pid)
41 		child_main();
42 
43 	if (SAFE_WAITPID(child_pid, &status, WUNTRACED) != child_pid)
44 		tst_brk(TBROK, "Received event from unexpected PID");
45 
46 #if defined(__i386__) || defined(__x86_64__)
47 	SAFE_PTRACE(PTRACE_ATTACH, child_pid, NULL, NULL);
48 	SAFE_PTRACE(PTRACE_POKEUSER, child_pid,
49 		(void *)offsetof(struct user, u_debugreg[0]), (void *)1);
50 	SAFE_PTRACE(PTRACE_POKEUSER, child_pid,
51 		(void *)offsetof(struct user, u_debugreg[0]), (void *)2);
52 
53 	addr = ptrace(PTRACE_PEEKUSER, child_pid,
54 	              (void*)offsetof(struct user, u_debugreg[0]), NULL);
55 #endif
56 
57 	if (addr == 2)
58 		tst_res(TPASS, "The rd0 was set on second PTRACE_POKEUSR");
59 	else
60 		tst_res(TFAIL, "The rd0 wasn't set on second PTRACE_POKEUSER");
61 
62 	SAFE_PTRACE(PTRACE_DETACH, child_pid, NULL, NULL);
63 	SAFE_KILL(child_pid, SIGCONT);
64 	child_pid = 0;
65 	tst_reap_children();
66 }
67 
cleanup(void)68 static void cleanup(void)
69 {
70 	/* Main process terminated by tst_brk() with child still paused */
71 	if (child_pid)
72 		SAFE_KILL(child_pid, SIGKILL);
73 }
74 
75 static struct tst_test test = {
76 	.test_all = run,
77 	.cleanup = cleanup,
78 	.forks_child = 1,
79 	.supported_archs = (const char *const []) {
80 		"x86",
81 		"x86_64",
82 		NULL
83 	},
84 	.tags = (const struct tst_tag[]) {
85 		{"linux-git", "bd14406b78e6"},
86 		{}
87 	}
88 };
89