/*
* Copyright (C) Igor Sysoev
* Copyright (C) NGINX, Inc.
*/
#include <nxt_main.h>
#include <sys/types.h>
#include <nxt_conf.h>
#include <nxt_clone.h>
#if (NXT_HAVE_CLONE)
pid_t
nxt_clone(nxt_int_t flags)
{
#if defined(__s390x__) || defined(__s390__) || defined(__CRIS__)
return syscall(__NR_clone, NULL, flags);
#else
return syscall(__NR_clone, flags, NULL);
#endif
}
#endif
#if (NXT_HAVE_CLONE_NEWUSER)
/* map uid 65534 to unit pid */
#define NXT_DEFAULT_UNPRIV_MAP "65534 %d 1"
nxt_int_t nxt_clone_proc_setgroups(nxt_task_t *task, pid_t child_pid,
const char *str);
nxt_int_t nxt_clone_proc_map_set(nxt_task_t *task, const char* mapfile,
pid_t pid, nxt_int_t defval, nxt_conf_value_t *mapobj);
nxt_int_t nxt_clone_proc_map_write(nxt_task_t *task, const char *mapfile,
pid_t pid, u_char *mapinfo);
typedef struct {
nxt_int_t container;
nxt_int_t host;
nxt_int_t size;
} nxt_clone_procmap_t;
nxt_int_t
nxt_clone_proc_setgroups(nxt_task_t *task, pid_t child_pid, const char *str)
{
int fd, n;
u_char *p, *end;
u_char path[PATH_MAX];
end = path + PATH_MAX;
p = nxt_sprintf(path, end, "/proc/%d/setgroups", child_pid);
*p = '\0';
if (nxt_slow_path(p == end)) {
nxt_alert(task, "error write past the buffer: %s", path);
return NXT_ERROR;
}
fd = open((char *)path, O_RDWR);
if (fd == -1) {
/*
* If the /proc/pid/setgroups doesn't exists, we are
* safe to set uid/gid maps. But if the error is anything
* other than ENOENT, then we should abort and let user know.
*/
if (errno != ENOENT) {
nxt_alert(task, "open(%s): %E", path, nxt_errno);
return NXT_ERROR;
}
return NXT_OK;
}
n = write(fd, str, strlen(str));
close(fd);
if (nxt_slow_path(n == -1)) {
nxt_alert(task, "write(%s): %E", path, nxt_errno);
return NXT_ERROR;
}
return NXT_OK;
}
nxt_int_t
nxt_clone_proc_map_write(nxt_task_t *task, const char *mapfile, pid_t pid,
u_char *mapinfo)
{
int len, mapfd;
u_char *p, *end;
ssize_t n;
u_char buf[256];
end = buf + sizeof(buf);
p = nxt_sprintf(buf, end, "/proc/%d/%s", pid, mapfile);
if (nxt_slow_path(p == end)) {
nxt_alert(task, "writing past the buffer");
return NXT_ERROR;
}
*p = '\0';
mapfd = open((char*)buf, O_RDWR);
if (nxt_slow_path(mapfd == -1)) {
nxt_alert(task, "failed to open proc map (%s) %E", buf, nxt_errno);
return NXT_ERROR;
}
len = nxt_strlen(mapinfo);
n = write(mapfd, (char *)mapinfo, len);
if (nxt_slow_path(n != len)) {
if (n == -1 && nxt_errno == EINVAL) {
nxt_alert(task, "failed to write %s: Check kernel maximum " \
"allowed lines %E", buf, nxt_errno);
} else {
nxt_alert(task, "failed to write proc map (%s) %E", buf,
nxt_errno);
}
close(mapfd);
return NXT_ERROR;
}
close(mapfd);
return NXT_OK;
}
nxt_int_t
nxt_clone_proc_map_set(nxt_task_t *task, const char* mapfile, pid_t pid,
nxt_int_t defval, nxt_conf_value_t *mapobj)
{
u_char *p, *end, *mapinfo;
nxt_int_t container, host, size;
nxt_int_t ret, len, count, i;
nxt_conf_value_t *obj, *value;
static nxt_str_t str_cont = nxt_string("container");
static nxt_str_t str_host = nxt_string("host");
static nxt_str_t str_size = nxt_string("size");
/*
* uid_map one-entry size:
* alloc space for 3 numbers (32bit) plus 2 spaces and \n.
*/
len = sizeof(u_char) * (10 + 10 + 10 + 2 + 1);
if (mapobj != NULL) {
count = nxt_conf_array_elements_count(mapobj);
if (count == 0) {
goto default_map;
}
len = len * count + 1;
mapinfo = nxt_malloc(len);
if (nxt_slow_path(mapinfo == NULL)) {
nxt_alert(task, "failed to allocate uid_map buffer");
return NXT_ERROR;
}
p = mapinfo;
end = mapinfo + len;
for (i = 0; i < count; i++) {
obj = nxt_conf_get_array_element(mapobj, i);
value = nxt_conf_get_object_member(obj, &str_cont, NULL);
container = nxt_conf_get_integer(value);
value = nxt_conf_get_object_member(obj, &str_host, NULL);
host = nxt_conf_get_integer(value);
value = nxt_conf_get_object_member(obj, &str_size, NULL);
size = nxt_conf_get_integer(value);
p = nxt_sprintf(p, end, "%d %d %d", container, host, size);
if (nxt_slow_path(p == end)) {
nxt_alert(task, "write past the uid_map buffer");
nxt_free(mapinfo);
return NXT_ERROR;
}
if (i+1 < count) {
*p++ = '\n';
} else {
*p = '\0';
}
}
} else {
default_map:
mapinfo = nxt_malloc(len);
if (nxt_slow_path(mapinfo == NULL)) {
nxt_alert(task, "failed to allocate uid_map buffer");
return NXT_ERROR;
}
end = mapinfo + len;
p = nxt_sprintf(mapinfo, end, NXT_DEFAULT_UNPRIV_MAP, defval);
*p = '\0';
if (nxt_slow_path(p == end)) {
nxt_alert(task, "write past the %s buffer", mapfile);
nxt_free(mapinfo);
return NXT_ERROR;
}
}
ret = nxt_clone_proc_map_write(task, mapfile, pid, mapinfo);
nxt_free(mapinfo);
return ret;
}
nxt_int_t
nxt_clone_proc_map(nxt_task_t *task, pid_t pid, nxt_process_clone_t *clone)
{
nxt_int_t ret;
nxt_int_t uid, gid;
const char *rule;
nxt_runtime_t *rt;
rt = task->thread->runtime;
uid = geteuid();
gid = getegid();
rule = rt->capabilities.setid ? "allow" : "deny";
ret = nxt_clone_proc_map_set(task, "uid_map", pid, uid, clone->uidmap);
if (nxt_slow_path(ret != NXT_OK)) {
return NXT_ERROR;
}
ret = nxt_clone_proc_setgroups(task, pid, rule);
if (nxt_slow_path(ret != NXT_OK)) {
nxt_alert(task, "failed to write /proc/%d/setgroups", pid);
return NXT_ERROR;
}
ret = nxt_clone_proc_map_set(task, "gid_map", pid, gid, clone->gidmap);
if (nxt_slow_path(ret != NXT_OK)) {
return NXT_ERROR;
}
return NXT_OK;
}
#endif
