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#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <sched.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/wait.h>
#include <linux/seccomp.h>
#include <linux/filter.h>
#include <linux/audit.h>
#include <errno.h>
#include "gluten.h"
#include "actions.h"
static bool is_cookie_valid(int notifyFd, uint64_t id)
{
return ioctl(notifyFd, SECCOMP_IOCTL_NOTIF_ID_VALID, &id) == 0;
}
static int send_target(const struct seccomp_notif_resp *resp, int notifyfd)
{
if (!is_cookie_valid(notifyfd, resp->id)) {
fprintf(stderr, "the response id isn't valid\ncheck if the targets has already terminated\n");
return -1;
}
if (ioctl(notifyfd, SECCOMP_IOCTL_NOTIF_SEND, resp) < 0) {
if (errno != EINPROGRESS) {
perror("sending the response");
return -1;
}
}
return 0;
}
static int send_inject_target(const struct seccomp_notif_addfd *resp,
int notifyfd)
{
if (!is_cookie_valid(notifyfd, resp->id)) {
fprintf(stderr, "the response id isn't valid\ncheck if the targets has already terminated\n");
return -1;
}
if (ioctl(notifyfd, SECCOMP_IOCTL_NOTIF_ADDFD, resp) < 0) {
if (errno != EINPROGRESS) {
perror("sending the response");
return -1;
}
}
return 0;
}
static void proc_ns_name(unsigned i, char *ns)
{
switch (i) {
case NS_CGROUP:
snprintf(ns, PATH_MAX + 1, "cgroup");
break;
case NS_IPC:
snprintf(ns, PATH_MAX + 1, "ipc");
break;
case NS_NET:
snprintf(ns, PATH_MAX + 1, "net");
break;
case NS_MOUNT:
snprintf(ns, PATH_MAX + 1, "mnt");
break;
case NS_PID:
snprintf(ns, PATH_MAX + 1, "pid");
break;
case NS_USER:
snprintf(ns, PATH_MAX + 1, "user");
break;
case NS_UTS:
snprintf(ns, PATH_MAX + 1, "uts");
break;
case NS_TIME:
snprintf(ns, PATH_MAX + 1, "time");
break;
default:
fprintf(stderr, "unrecognized namespace index %d\n", i);
}
}
static int set_namespaces(const struct act_call *a, int tpid)
{
char path[PATH_MAX + 1];
char ns_name[PATH_MAX / 2];
struct ns_spec ns;
int fd;
unsigned int i;
for (i = 0, ns = (a->context).ns[i]; i < sizeof(enum ns_type);
i++, ns = (a->context).ns[i]) {
proc_ns_name(i, ns_name);
switch (ns.type) {
case NS_NONE:
continue;
case NS_SPEC_TARGET:
snprintf(path, sizeof(path), "/proc/%d/ns/%s", tpid,
ns_name);
break;
case NS_SPEC_PID:
snprintf(path, sizeof(path), "/proc/%d/ns/%s", ns.pid,
ns_name);
break;
case NS_SPEC_PATH:
snprintf(path, sizeof(path), "%s", ns.path);
break;
}
if ((fd = open(path, O_CLOEXEC)) < 0) {
fprintf(stderr, "open for file %s: %s", path,
strerror(errno));
return -1;
}
if (setns(fd, 0) != 0) {
perror("setns");
return -1;
}
}
return 0;
}
static int execute_syscall(void *args)
{
struct arg_clone *a = (struct arg_clone *)args;
const struct act_call *c = a->args;
if (set_namespaces(a->args, a->pid) < 0) {
exit(EXIT_FAILURE);
}
/* execute syscall */
a->ret = syscall(c->nr, c->args[0], c->args[1], c->args[2], c->args[3],
c->args[4], c->args[5]);
a->err = errno;
if (a->ret < 0) {
perror("syscall");
exit(EXIT_FAILURE);
}
exit(0);
}
int do_call(struct arg_clone *c)
{
char stack[STACK_SIZE];
pid_t child;
c->ret = -1;
c->err = 0;
/* Create a process that will be moved to the namespace */
child = clone(execute_syscall, stack + sizeof(stack),
CLONE_FILES | CLONE_VM | SIGCHLD, (void *)c);
if (child == -1) {
perror("clone");
return -1;
}
wait(NULL);
return 0;
}
int do_actions(struct action actions[], unsigned int n_actions, int pid,
int notifyfd, uint64_t id)
{
struct seccomp_notif_resp resp;
struct arg_clone c;
unsigned int i;
for (i = 0; i < n_actions; i++) {
switch (actions[i].type) {
case A_CALL:
resp.id = id;
resp.val = 0;
resp.flags = 0;
c.args = &actions[i].call;
c.pid = pid;
if (do_call(&c) == -1) {
resp.error = c.err;
if (send_target(&resp, notifyfd) == -1)
return -1;
}
break;
case A_BLOCK:
resp.id = id;
resp.val = 0;
resp.flags = 0;
resp.error = actions[i].block.error;
if (send_target(&resp, notifyfd) == -1)
return -1;
break;
case A_RETURN:
resp.id = id;
resp.flags = 0;
resp.error = 0;
resp.val = actions[i].ret.value;
if (send_target(&resp, notifyfd) == -1)
return -1;
break;
case A_CONT:
resp.id = id;
resp.flags |= SECCOMP_USER_NOTIF_FLAG_CONTINUE;
resp.error = 0;
resp.val = 0;
if (send_target(&resp, notifyfd) == -1)
return -1;
break;
default:
fprintf(stderr, "unknow action %d \n", actions[i].type);
}
}
return 0;
}
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