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/*
* SPDX-FileCopyrightText: 2013 Eric Biederman
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <config.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <stdbool.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "defines.h"
#include "prototypes.h"
#include "subordinateio.h"
#include "getdef.h"
#include "idmapping.h"
#include "shadowlog.h"
/*
* Global variables
*/
const char *Prog;
static bool verify_range(struct passwd *pw, struct map_range *range)
{
/* An empty range is invalid */
if (range->count == 0)
return false;
/* Test /etc/subuid */
if (have_sub_uids(pw->pw_name, range->lower, range->count))
return true;
/* Allow a process to map its own uid */
if ((range->count == 1) && (pw->pw_uid == range->lower))
return true;
return false;
}
static void verify_ranges(struct passwd *pw, int ranges,
struct map_range *mappings)
{
struct map_range *mapping;
int idx;
mapping = mappings;
for (idx = 0; idx < ranges; idx++, mapping++) {
if (!verify_range(pw, mapping)) {
fprintf(stderr, _( "%s: uid range [%lu-%lu) -> [%lu-%lu) not allowed\n"),
Prog,
mapping->upper,
mapping->upper + mapping->count,
mapping->lower,
mapping->lower + mapping->count);
exit(EXIT_FAILURE);
}
}
}
static void usage(void)
{
fprintf(stderr, _("usage: %s <pid> <uid> <loweruid> <count> [ <uid> <loweruid> <count> ] ... \n"), Prog);
exit(EXIT_FAILURE);
}
/*
* newuidmap - Set the uid_map for the specified process
*/
int main(int argc, char **argv)
{
char proc_dir_name[32];
char *target_str;
pid_t target;
int proc_dir_fd;
int ranges;
struct map_range *mappings;
struct stat st;
struct passwd *pw;
int written;
Prog = Basename (argv[0]);
log_set_progname(Prog);
log_set_logfd(stderr);
/*
* The valid syntax are
* newuidmap target_pid
*/
if (argc < 2)
usage();
/* Find the process that needs its user namespace
* uid mapping set.
*/
target_str = argv[1];
if (!get_pid(target_str, &target))
usage();
/* max string length is 6 + 10 + 1 + 1 = 18, allocate 32 bytes */
written = snprintf(proc_dir_name, sizeof(proc_dir_name), "/proc/%u/",
target);
if ((written <= 0) || (written >= sizeof(proc_dir_name))) {
fprintf(stderr, "%s: snprintf of proc path failed: %s\n",
Prog, strerror(errno));
}
proc_dir_fd = open(proc_dir_name, O_DIRECTORY);
if (proc_dir_fd < 0) {
fprintf(stderr, _("%s: Could not open proc directory for target %u\n"),
Prog, target);
return EXIT_FAILURE;
}
/* Who am i? */
pw = get_my_pwent ();
if (NULL == pw) {
fprintf (stderr,
_("%s: Cannot determine your user name.\n"),
Prog);
SYSLOG ((LOG_WARN, "Cannot determine the user name of the caller (UID %lu)",
(unsigned long) getuid ()));
return EXIT_FAILURE;
}
/* Get the effective uid and effective gid of the target process */
if (fstat(proc_dir_fd, &st) < 0) {
fprintf(stderr, _("%s: Could not stat directory for target %u\n"),
Prog, target);
return EXIT_FAILURE;
}
/* Verify real user and real group matches the password entry
* and the effective user and group of the program whose
* mappings we have been asked to set.
*/
if ((getuid() != pw->pw_uid) ||
(!getdef_bool("GRANT_AUX_GROUP_SUBIDS") && (getgid() != pw->pw_gid)) ||
(pw->pw_uid != st.st_uid) ||
(getgid() != st.st_gid)) {
fprintf(stderr, _( "%s: Target process %u is owned by a different user: uid:%lu pw_uid:%lu st_uid:%lu, gid:%lu pw_gid:%lu st_gid:%lu\n" ),
Prog, target,
(unsigned long int)getuid(), (unsigned long int)pw->pw_uid, (unsigned long int)st.st_uid,
(unsigned long int)getgid(), (unsigned long int)pw->pw_gid, (unsigned long int)st.st_gid);
return EXIT_FAILURE;
}
if (!sub_uid_open(O_RDONLY)) {
return EXIT_FAILURE;
}
ranges = ((argc - 2) + 2) / 3;
mappings = get_map_ranges(ranges, argc - 2, argv + 2);
if (!mappings)
usage();
verify_ranges(pw, ranges, mappings);
write_mapping(proc_dir_fd, ranges, mappings, "uid_map", pw->pw_uid);
sub_uid_close();
return EXIT_SUCCESS;
}
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