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