freebsd-dev/lib/libcapsicum/libcapsicum_pwd.c
Pawel Jakub Dawidek 42a8595256 Please welcome casperd daemon. It (and its services) will be responsible for
giving access to functionality that is not available in capability mode
sandbox. The functionality can be precisely restricted.

Start with the following services:
- system.dns - provides API compatible to:
	- gethostbyname(3),
	- gethostbyname2(3),
	- gethostbyaddr(3),
	- getaddrinfo(3),
	- getnameinfo(3),
- system.grp - provides getgrent(3)-compatible API,
- system.pwd - provides getpwent(3)-compatible API,
- system.random - allows to obtain entropy from /dev/random,
- system.sysctl - provides sysctlbyname(3-compatible API.

Sponsored by:	The FreeBSD Foundation
2013-12-02 08:21:28 +00:00

385 lines
9.0 KiB
C

/*-
* Copyright (c) 2013 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Pawel Jakub Dawidek under sponsorship from
* the FreeBSD Foundation.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <assert.h>
#include <errno.h>
#include <pwd.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <nv.h>
#include "libcapsicum.h"
#include "libcapsicum_pwd.h"
static struct passwd gpwd;
static char *gbuffer;
static size_t gbufsize;
static int
passwd_resize(void)
{
char *buf;
if (gbufsize == 0)
gbufsize = 1024;
else
gbufsize *= 2;
buf = gbuffer;
gbuffer = realloc(buf, gbufsize);
if (gbuffer == NULL) {
free(buf);
gbufsize = 0;
return (ENOMEM);
}
memset(gbuffer, 0, gbufsize);
return (0);
}
static int
passwd_unpack_string(const nvlist_t *nvl, const char *fieldname, char **fieldp,
char **bufferp, size_t *bufsizep)
{
const char *str;
size_t len;
str = nvlist_get_string(nvl, fieldname);
len = strlcpy(*bufferp, str, *bufsizep);
if (len >= *bufsizep)
return (ERANGE);
*fieldp = *bufferp;
*bufferp += len + 1;
*bufsizep -= len + 1;
return (0);
}
static int
passwd_unpack(const nvlist_t *nvl, struct passwd *pwd, char *buffer,
size_t bufsize)
{
int error;
if (!nvlist_exists_string(nvl, "pw_name"))
return (EINVAL);
memset(pwd, 0, sizeof(*pwd));
error = passwd_unpack_string(nvl, "pw_name", &pwd->pw_name, &buffer,
&bufsize);
if (error != 0)
return (error);
pwd->pw_uid = (uid_t)nvlist_get_number(nvl, "pw_uid");
pwd->pw_gid = (gid_t)nvlist_get_number(nvl, "pw_gid");
pwd->pw_change = (time_t)nvlist_get_number(nvl, "pw_change");
error = passwd_unpack_string(nvl, "pw_passwd", &pwd->pw_passwd, &buffer,
&bufsize);
if (error != 0)
return (error);
error = passwd_unpack_string(nvl, "pw_class", &pwd->pw_class, &buffer,
&bufsize);
if (error != 0)
return (error);
error = passwd_unpack_string(nvl, "pw_gecos", &pwd->pw_gecos, &buffer,
&bufsize);
if (error != 0)
return (error);
error = passwd_unpack_string(nvl, "pw_dir", &pwd->pw_dir, &buffer,
&bufsize);
if (error != 0)
return (error);
error = passwd_unpack_string(nvl, "pw_shell", &pwd->pw_shell, &buffer,
&bufsize);
if (error != 0)
return (error);
pwd->pw_expire = (time_t)nvlist_get_number(nvl, "pw_expire");
pwd->pw_fields = (int)nvlist_get_number(nvl, "pw_fields");
return (0);
}
static int
cap_getpwcommon_r(cap_channel_t *chan, const char *cmd, const char *login,
uid_t uid, struct passwd *pwd, char *buffer, size_t bufsize,
struct passwd **result)
{
nvlist_t *nvl;
bool getpw_r;
int error;
nvl = nvlist_create(0);
nvlist_add_string(nvl, "cmd", cmd);
if (strcmp(cmd, "getpwent") == 0 || strcmp(cmd, "getpwent_r") == 0) {
/* Add nothing. */
} else if (strcmp(cmd, "getpwnam") == 0 ||
strcmp(cmd, "getpwnam_r") == 0) {
nvlist_add_string(nvl, "name", login);
} else if (strcmp(cmd, "getpwuid") == 0 ||
strcmp(cmd, "getpwuid_r") == 0) {
nvlist_add_number(nvl, "uid", (uint64_t)uid);
} else {
abort();
}
nvl = cap_xfer_nvlist(chan, nvl);
if (nvl == NULL) {
assert(errno != 0);
*result = NULL;
return (errno);
}
error = (int)nvlist_get_number(nvl, "error");
if (error != 0) {
nvlist_destroy(nvl);
*result = NULL;
return (error);
}
if (!nvlist_exists_string(nvl, "pw_name")) {
/* Not found. */
nvlist_destroy(nvl);
*result = NULL;
return (0);
}
getpw_r = (strcmp(cmd, "getpwent_r") == 0 ||
strcmp(cmd, "getpwnam_r") == 0 || strcmp(cmd, "getpwuid_r") == 0);
for (;;) {
error = passwd_unpack(nvl, pwd, buffer, bufsize);
if (getpw_r || error != ERANGE)
break;
assert(buffer == gbuffer);
assert(bufsize == gbufsize);
error = passwd_resize();
if (error != 0)
break;
/* Update pointers after resize. */
buffer = gbuffer;
bufsize = gbufsize;
}
nvlist_destroy(nvl);
if (error == 0)
*result = pwd;
else
*result = NULL;
return (error);
}
static struct passwd *
cap_getpwcommon(cap_channel_t *chan, const char *cmd, const char *login,
uid_t uid)
{
struct passwd *result;
int error, serrno;
serrno = errno;
error = cap_getpwcommon_r(chan, cmd, login, uid, &gpwd, gbuffer,
gbufsize, &result);
if (error != 0) {
errno = error;
return (NULL);
}
errno = serrno;
return (result);
}
struct passwd *
cap_getpwent(cap_channel_t *chan)
{
return (cap_getpwcommon(chan, "getpwent", NULL, 0));
}
struct passwd *
cap_getpwnam(cap_channel_t *chan, const char *login)
{
return (cap_getpwcommon(chan, "getpwnam", login, 0));
}
struct passwd *
cap_getpwuid(cap_channel_t *chan, uid_t uid)
{
return (cap_getpwcommon(chan, "getpwuid", NULL, uid));
}
int
cap_getpwent_r(cap_channel_t *chan, struct passwd *pwd, char *buffer,
size_t bufsize, struct passwd **result)
{
return (cap_getpwcommon_r(chan, "getpwent_r", NULL, 0, pwd, buffer,
bufsize, result));
}
int
cap_getpwnam_r(cap_channel_t *chan, const char *name, struct passwd *pwd,
char *buffer, size_t bufsize, struct passwd **result)
{
return (cap_getpwcommon_r(chan, "getpwnam_r", name, 0, pwd, buffer,
bufsize, result));
}
int
cap_getpwuid_r(cap_channel_t *chan, uid_t uid, struct passwd *pwd, char *buffer,
size_t bufsize, struct passwd **result)
{
return (cap_getpwcommon_r(chan, "getpwuid_r", NULL, uid, pwd, buffer,
bufsize, result));
}
int
cap_setpassent(cap_channel_t *chan, int stayopen)
{
nvlist_t *nvl;
nvl = nvlist_create(0);
nvlist_add_string(nvl, "cmd", "setpassent");
nvlist_add_bool(nvl, "stayopen", stayopen != 0);
nvl = cap_xfer_nvlist(chan, nvl);
if (nvl == NULL)
return (0);
if (nvlist_get_number(nvl, "error") != 0) {
errno = nvlist_get_number(nvl, "error");
nvlist_destroy(nvl);
return (0);
}
nvlist_destroy(nvl);
return (1);
}
static void
cap_set_end_pwent(cap_channel_t *chan, const char *cmd)
{
nvlist_t *nvl;
nvl = nvlist_create(0);
nvlist_add_string(nvl, "cmd", cmd);
/* Ignore any errors, we have no way to report them. */
nvlist_destroy(cap_xfer_nvlist(chan, nvl));
}
void
cap_setpwent(cap_channel_t *chan)
{
cap_set_end_pwent(chan, "setpwent");
}
void
cap_endpwent(cap_channel_t *chan)
{
cap_set_end_pwent(chan, "endpwent");
}
int
cap_pwd_limit_cmds(cap_channel_t *chan, const char * const *cmds, size_t ncmds)
{
nvlist_t *limits, *nvl;
unsigned int i;
if (cap_limit_get(chan, &limits) < 0)
return (-1);
if (limits == NULL) {
limits = nvlist_create(0);
} else {
if (nvlist_exists_nvlist(limits, "cmds"))
nvlist_free_nvlist(limits, "cmds");
}
nvl = nvlist_create(0);
for (i = 0; i < ncmds; i++)
nvlist_add_null(nvl, cmds[i]);
nvlist_move_nvlist(limits, "cmds", nvl);
return (cap_limit_set(chan, limits));
}
int
cap_pwd_limit_fields(cap_channel_t *chan, const char * const *fields,
size_t nfields)
{
nvlist_t *limits, *nvl;
unsigned int i;
if (cap_limit_get(chan, &limits) < 0)
return (-1);
if (limits == NULL) {
limits = nvlist_create(0);
} else {
if (nvlist_exists_nvlist(limits, "fields"))
nvlist_free_nvlist(limits, "fields");
}
nvl = nvlist_create(0);
for (i = 0; i < nfields; i++)
nvlist_add_null(nvl, fields[i]);
nvlist_move_nvlist(limits, "fields", nvl);
return (cap_limit_set(chan, limits));
}
int
cap_pwd_limit_users(cap_channel_t *chan, const char * const *names,
size_t nnames, uid_t *uids, size_t nuids)
{
nvlist_t *limits, *users;
unsigned int i;
if (cap_limit_get(chan, &limits) < 0)
return (-1);
if (limits == NULL) {
limits = nvlist_create(0);
} else {
if (nvlist_exists_nvlist(limits, "users"))
nvlist_free_nvlist(limits, "users");
}
users = nvlist_create(0);
for (i = 0; i < nuids; i++)
nvlist_addf_number(users, (uint64_t)uids[i], "uid%u", i);
for (i = 0; i < nnames; i++)
nvlist_addf_string(users, names[i], "name%u", i);
nvlist_move_nvlist(limits, "users", users);
return (cap_limit_set(chan, limits));
}