b03df41906
parent, user_id, and group_id are unused. Signed-off-by: Serge Hallyn <shallyn@cisco.com>
187 lines
5.3 KiB
C
187 lines
5.3 KiB
C
/*
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* Copyright (c) 2013 Eric Biederman
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the copyright holders or contributors may not be used to
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* endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <config.h>
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#include <stdio.h>
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#include <string.h>
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#include <errno.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include "defines.h"
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#include "prototypes.h"
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#include "subordinateio.h"
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#include "idmapping.h"
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/*
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* Global variables
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*/
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const char *Prog;
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static bool verify_range(struct passwd *pw, struct map_range *range)
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{
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/* An empty range is invalid */
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if (range->count == 0)
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return false;
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/* Test /etc/subuid */
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if (have_sub_uids(pw->pw_name, range->lower, range->count))
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return true;
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/* Allow a process to map its own uid */
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if ((range->count == 1) && (pw->pw_uid == range->lower))
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return true;
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return false;
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}
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static void verify_ranges(struct passwd *pw, int ranges,
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struct map_range *mappings)
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{
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struct map_range *mapping;
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int idx;
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mapping = mappings;
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for (idx = 0; idx < ranges; idx++, mapping++) {
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if (!verify_range(pw, mapping)) {
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fprintf(stderr, _( "%s: uid range [%lu-%lu) -> [%lu-%lu) not allowed\n"),
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Prog,
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mapping->upper,
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mapping->upper + mapping->count,
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mapping->lower,
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mapping->lower + mapping->count);
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exit(EXIT_FAILURE);
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}
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}
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}
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void usage(void)
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{
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fprintf(stderr, _("usage: %s <pid> <uid> <loweruid> <count> [ <uid> <loweruid> <count> ] ... \n"), Prog);
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exit(EXIT_FAILURE);
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}
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/*
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* newuidmap - Set the uid_map for the specified process
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*/
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int main(int argc, char **argv)
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{
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char proc_dir_name[32];
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char *target_str;
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pid_t target;
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int proc_dir_fd;
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int ranges;
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struct map_range *mappings;
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struct stat st;
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struct passwd *pw;
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int written;
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Prog = Basename (argv[0]);
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/*
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* The valid syntax are
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* newuidmap target_pid
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*/
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if (argc < 2)
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usage();
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/* Find the process that needs its user namespace
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* uid mapping set.
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*/
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target_str = argv[1];
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if (!get_pid(target_str, &target))
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usage();
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/* max string length is 6 + 10 + 1 + 1 = 18, allocate 32 bytes */
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written = snprintf(proc_dir_name, sizeof(proc_dir_name), "/proc/%u/",
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target);
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if ((written <= 0) || (written >= sizeof(proc_dir_name))) {
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fprintf(stderr, "%s: snprintf of proc path failed: %s\n",
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Prog, strerror(errno));
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}
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proc_dir_fd = open(proc_dir_name, O_DIRECTORY);
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if (proc_dir_fd < 0) {
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fprintf(stderr, _("%s: Could not open proc directory for target %u\n"),
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Prog, target);
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return EXIT_FAILURE;
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}
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/* Who am i? */
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pw = get_my_pwent ();
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if (NULL == pw) {
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fprintf (stderr,
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_("%s: Cannot determine your user name.\n"),
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Prog);
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SYSLOG ((LOG_WARN, "Cannot determine the user name of the caller (UID %lu)",
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(unsigned long) getuid ()));
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return EXIT_FAILURE;
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}
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/* Get the effective uid and effective gid of the target process */
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if (fstat(proc_dir_fd, &st) < 0) {
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fprintf(stderr, _("%s: Could not stat directory for target %u\n"),
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Prog, target);
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return EXIT_FAILURE;
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}
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/* Verify real user and real group matches the password entry
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* and the effective user and group of the program whose
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* mappings we have been asked to set.
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*/
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if ((getuid() != pw->pw_uid) ||
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(getgid() != pw->pw_gid) ||
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(pw->pw_uid != st.st_uid) ||
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(pw->pw_gid != st.st_gid)) {
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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" ),
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Prog, target,
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(unsigned long int)getuid(), (unsigned long int)pw->pw_uid, (unsigned long int)st.st_uid,
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(unsigned long int)getgid(), (unsigned long int)pw->pw_gid, (unsigned long int)st.st_gid);
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return EXIT_FAILURE;
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}
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if (!sub_uid_open(O_RDONLY)) {
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return EXIT_FAILURE;
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}
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ranges = ((argc - 2) + 2) / 3;
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mappings = get_map_ranges(ranges, argc - 2, argv + 2);
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if (!mappings)
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usage();
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verify_ranges(pw, ranges, mappings);
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write_mapping(proc_dir_fd, ranges, mappings, "uid_map", pw->pw_uid);
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sub_uid_close();
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return EXIT_SUCCESS;
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}
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