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newuidmap,newgidmap: New suid helpers for using subordinate uids and gids

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Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
This commit is contained in:
Eric W. Biederman
2013-01-22 01:20:07 -08:00
committed by Serge Hallyn
parent 2cffa14105
commit 673c2a6f9a
9 changed files with 856 additions and 2 deletions
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5
src/Makefile.am
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@@ -24,7 +24,8 @@ INCLUDES = \
bin_PROGRAMS = groups login su
sbin_PROGRAMS = nologin
ubin_PROGRAMS = faillog lastlog chage chfn chsh expiry gpasswd newgrp passwd
ubin_PROGRAMS = faillog lastlog chage chfn chsh expiry gpasswd newgrp passwd \
newgidmap newuidmap
usbin_PROGRAMS = \
chgpasswd \
chpasswd \
@@ -49,7 +50,7 @@ usbin_PROGRAMS = \
noinst_PROGRAMS = id sulogin
suidbins = su
suidubins = chage chfn chsh expiry gpasswd newgrp passwd
suidubins = chage chfn chsh expiry gpasswd newgrp passwd newuidmap newgidmap
if ACCT_TOOLS_SETUID
suidubins += chage chgpasswd chpasswd groupadd groupdel groupmod newusers useradd userdel usermod
endif

183
src/newgidmap.c Normal file
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@@ -0,0 +1,183 @@
/*
* Copyright (c) 2013 Eric Biederman
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the copyright holders or contributors may not be used to
* endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#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 "idmapping.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/subgid */
if (have_sub_gids(pw->pw_name, range->lower, range->count))
return true;
/* Allow a process to map it's own gid */
if ((range->count == 1) && (pw->pw_gid == 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: gid 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> <gid> <lowergid> <count> [ <gid> <lowergid> <count> ] ... \n"), Prog);
exit(EXIT_FAILURE);
}
/*
* newgidmap - Set the gid_map for the specified process
*/
int main(int argc, char **argv)
{
char proc_dir_name[PATH_MAX];
char *target_str;
pid_t target, parent;
int proc_dir_fd;
int ranges;
struct map_range *mappings;
struct stat st;
struct passwd *pw;
int written;
Prog = Basename (argv[0]);
/*
* The valid syntax are
* newgidmap target_pid
*/
if (argc < 2)
usage();
/* Find the process that needs it's user namespace
* gid mapping set.
*/
target_str = argv[1];
if (!get_pid(target_str, &target))
usage();
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) ||
(getgid() != pw->pw_gid) ||
(pw->pw_uid != st.st_uid) ||
(pw->pw_gid != st.st_gid)) {
fprintf(stderr, _( "%s: Target %u is owned by a different user\n" ),
Prog, target);
return EXIT_FAILURE;
}
if (!sub_gid_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, "gid_map");
sub_gid_close();
return EXIT_SUCCESS;
}

183
src/newuidmap.c Normal file
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@@ -0,0 +1,183 @@
/*
* Copyright (c) 2013 Eric Biederman
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the copyright holders or contributors may not be used to
* endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#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 "idmapping.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 it's 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);
}
}
}
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[PATH_MAX];
char *target_str;
pid_t target, parent;
int proc_dir_fd;
int ranges;
struct map_range *mappings;
struct stat st;
struct passwd *pw;
int written;
Prog = Basename (argv[0]);
/*
* The valid syntax are
* newuidmap target_pid
*/
if (argc < 2)
usage();
/* Find the process that needs it's user namespace
* uid mapping set.
*/
target_str = argv[1];
if (!get_pid(target_str, &target))
usage();
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) ||
(getgid() != pw->pw_gid) ||
(pw->pw_uid != st.st_uid) ||
(pw->pw_gid != st.st_gid)) {
fprintf(stderr, _( "%s: Target %u is owned by a different user\n" ),
Prog, target);
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");
sub_uid_close();
return EXIT_SUCCESS;
}