88 lines
2.2 KiB
C++
88 lines
2.2 KiB
C++
/*
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nsjail - CLONE_PID routines
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-----------------------------------------
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Copyright 2014 Google Inc. All Rights Reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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#include "pid.h"
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#include <linux/sched.h>
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#include <sched.h>
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#include <signal.h>
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#include <stddef.h>
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#include <sys/prctl.h>
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#include <unistd.h>
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#include "logs.h"
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#include "subproc.h"
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namespace pid {
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bool initNs(nsjconf_t* nsjconf) {
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if (nsjconf->mode != MODE_STANDALONE_EXECVE) {
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return true;
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}
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if (!nsjconf->clone_newpid) {
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return true;
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}
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LOG_D("Creating a dummy 'init' process");
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/*
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* If -Me is used then we need to create permanent init inside PID ns, otherwise only the
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* first clone/fork will work, and the rest will fail with ENOMEM (see 'man pid_namespaces'
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* for details on this behavior)
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*/
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pid_t pid = subproc::cloneProc(CLONE_FS, 0);
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if (pid == -1) {
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PLOG_E("Couldn't create a dummy init process");
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return false;
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}
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if (pid > 0) {
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LOG_D("Created a dummy 'init' process with PID=%d", pid);
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return true;
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}
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if (prctl(PR_SET_PDEATHSIG, SIGKILL, 0UL, 0UL, 0UL) == -1) {
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PLOG_W("(prctl(PR_SET_PDEATHSIG, SIGKILL) failed");
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}
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if (prctl(PR_SET_NAME, "ns-init", 0UL, 0UL, 0UL) == -1) {
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PLOG_W("(prctl(PR_SET_NAME, 'init') failed");
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}
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if (prctl(PR_SET_DUMPABLE, 0UL, 0UL, 0UL, 0UL) == -1) {
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PLOG_W("(prctl(PR_SET_DUMPABLE, 0) failed");
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}
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/* Act sort-a like a init by reaping zombie processes */
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struct sigaction sa = {};
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sa.sa_handler = SIG_DFL;
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sa.sa_flags = SA_NOCLDWAIT | SA_NOCLDSTOP;
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sa.sa_restorer = NULL;
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sigemptyset(&sa.sa_mask);
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if (sigaction(SIGCHLD, &sa, NULL) == -1) {
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PLOG_W("Couldn't set sighandler for SIGCHLD");
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}
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for (;;) {
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pause();
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}
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}
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} // namespace pid
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