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selftests/ptrace: add test cases for dead-locks 

[ Upstream commit 2de4e82318 ]

This adds test cases for ptrace deadlocks.

Additionally fixes a compile problem in get_syscall_info.c,
observed with gcc-4.8.4:

get_syscall_info.c: In function 'get_syscall_info':
get_syscall_info.c:93:3: error: 'for' loop initial declarations are only
                                 allowed in C99 mode
   for (unsigned int i = 0; i < ARRAY_SIZE(args); ++i) {
   ^
get_syscall_info.c:93:3: note: use option -std=c99 or -std=gnu99 to compile
                               your code

Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
5.4-rM2-2.2.x-imx-squashed
Bernd Edlinger 2020-03-20 21:26:19 +01:00 committed by Greg Kroah-Hartman
parent d8d15a4c44
commit 2f7a0de4e5
2 changed files with 88 additions and 2 deletions
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4
tools/testing/selftests/ptrace/Makefile
View File

@ -1,6 +1,6 @@
# SPDX-License-Identifier: GPL-2.0-only
CFLAGS += -iquote../../../../include/uapi -Wall
CFLAGS += -std=c99 -pthread -iquote../../../../include/uapi -Wall
TEST_GEN_PROGS := get_syscall_info peeksiginfo
TEST_GEN_PROGS := get_syscall_info peeksiginfo vmaccess
include ../lib.mk

86
tools/testing/selftests/ptrace/vmaccess.c 100644
View File

@ -0,0 +1,86 @@
// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2020 Bernd Edlinger <bernd.edlinger@hotmail.de>
* All rights reserved.
*
* Check whether /proc/$pid/mem can be accessed without causing deadlocks
* when de_thread is blocked with ->cred_guard_mutex held.
*/
#include "../kselftest_harness.h"
#include <stdio.h>
#include <fcntl.h>
#include <pthread.h>
#include <signal.h>
#include <unistd.h>
#include <sys/ptrace.h>
static void *thread(void *arg)
{
ptrace(PTRACE_TRACEME, 0, 0L, 0L);
return NULL;
}
TEST(vmaccess)
{
int f, pid = fork();
char mm[64];
if (!pid) {
pthread_t pt;
pthread_create(&pt, NULL, thread, NULL);
pthread_join(pt, NULL);
execlp("true", "true", NULL);
}
sleep(1);
sprintf(mm, "/proc/%d/mem", pid);
f = open(mm, O_RDONLY);
ASSERT_GE(f, 0);
close(f);
f = kill(pid, SIGCONT);
ASSERT_EQ(f, 0);
}
TEST(attach)
{
int s, k, pid = fork();
if (!pid) {
pthread_t pt;
pthread_create(&pt, NULL, thread, NULL);
pthread_join(pt, NULL);
execlp("sleep", "sleep", "2", NULL);
}
sleep(1);
k = ptrace(PTRACE_ATTACH, pid, 0L, 0L);
ASSERT_EQ(errno, EAGAIN);
ASSERT_EQ(k, -1);
k = waitpid(-1, &s, WNOHANG);
ASSERT_NE(k, -1);
ASSERT_NE(k, 0);
ASSERT_NE(k, pid);
ASSERT_EQ(WIFEXITED(s), 1);
ASSERT_EQ(WEXITSTATUS(s), 0);
sleep(1);
k = ptrace(PTRACE_ATTACH, pid, 0L, 0L);
ASSERT_EQ(k, 0);
k = waitpid(-1, &s, 0);
ASSERT_EQ(k, pid);
ASSERT_EQ(WIFSTOPPED(s), 1);
ASSERT_EQ(WSTOPSIG(s), SIGSTOP);
k = ptrace(PTRACE_DETACH, pid, 0L, 0L);
ASSERT_EQ(k, 0);
k = waitpid(-1, &s, 0);
ASSERT_EQ(k, pid);
ASSERT_EQ(WIFEXITED(s), 1);
ASSERT_EQ(WEXITSTATUS(s), 0);
k = waitpid(-1, NULL, 0);
ASSERT_EQ(k, -1);
ASSERT_EQ(errno, ECHILD);
}
TEST_HARNESS_MAIN