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/*
SSSD
Kerberos 5 Backend Module -- tgt_req child
Authors:
Sumit Bose <sbose@redhat.com>
Copyright (C) 2009 Red Hat
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <krb5/krb5.h>
#include <sys/types.h>
#include <security/pam_modules.h>
#include "util/util.h"
#include "providers/dp_backend.h"
#include "providers/krb5/krb5_auth.h"
static int pack_response_packet(uint8_t *buf, int status, int type,
const char *data)
{
int len;
int p=0;
if ((3*sizeof(int32_t) + strlen(data)+1) > MAX_CHILD_MSG_SIZE) {
return -1;
}
((int32_t *)(&buf[p]))[0] = status;
p += sizeof(int32_t);
((int32_t *)(&buf[p]))[0] = type;
p += sizeof(int32_t);
len = strlen(data)+1;
((int32_t *)(&buf[p]))[0] = len;
p += sizeof(int32_t);
memcpy(&buf[p], data, len);
p += len;
return p;
}
void tgt_req_child(int fd, struct krb5_req *kr)
{
int ret;
krb5_error_code kerr = 0;
char *pass_str = NULL;
uint8_t buf[MAX_CHILD_MSG_SIZE];
int size = 0;
const char *cc_name;
char *env;
const char *krb5_error_msg;
int pam_status = PAM_SYSTEM_ERR;
ret = setgid(kr->pd->gr_gid);
if (ret == -1) {
DEBUG(1, ("setgid failed [%d][%s].\n", errno, strerror(errno)));
_exit(-1);
}
ret = setuid(kr->pd->pw_uid);
if (ret == -1) {
DEBUG(1, ("setuid failed [%d][%s].\n", errno, strerror(errno)));
_exit(-1);
}
ret = setegid(kr->pd->gr_gid);
if (ret == -1) {
DEBUG(1, ("setegid failed [%d][%s].\n", errno, strerror(errno)));
_exit(-1);
}
ret = seteuid(kr->pd->pw_uid);
if (ret == -1) {
DEBUG(1, ("seteuid failed [%d][%s].\n", errno, strerror(errno)));
_exit(-1);
}
pass_str = talloc_strndup(kr, (const char *) kr->pd->authtok,
kr->pd->authtok_size);
if (pass_str == NULL) {
DEBUG(1, ("talloc_strndup failed.\n"));
_exit(-1);
}
kerr = krb5_get_init_creds_password(kr->ctx, kr->creds, kr->princ,
pass_str, NULL, NULL, 0, NULL,
kr->options);
if (kerr != 0) {
KRB5_DEBUG(1, kerr);
if (kerr == KRB5_KDC_UNREACH) {
pam_status = PAM_AUTHINFO_UNAVAIL;
}
goto childfailed;
}
memset(pass_str, 0, kr->pd->authtok_size);
talloc_free(pass_str);
memset(kr->pd->authtok, 0, kr->pd->authtok_size);
kerr = krb5_cc_default(kr->ctx, &kr->cc);
if (kerr != 0) {
KRB5_DEBUG(1, kerr);
goto childfailed;
}
kerr = krb5_cc_initialize(kr->ctx, kr->cc, kr->princ);
if (kerr != 0) {
KRB5_DEBUG(1, kerr);
goto childfailed;
}
kerr = krb5_cc_store_cred(kr->ctx, kr->cc, kr->creds);
if (kerr != 0) {
KRB5_DEBUG(1, kerr);
krb5_cc_destroy(kr->ctx, kr->cc);
goto childfailed;
}
cc_name = krb5_cc_get_name(kr->ctx, kr->cc);
if (cc_name == NULL) {
DEBUG(1, ("krb5_cc_get_name failed.\n"));
krb5_cc_destroy(kr->ctx, kr->cc);
_exit(-1);
}
env = talloc_asprintf(kr, "%s=%s",CCACHE_ENV_NAME, cc_name);
if (env == NULL) {
DEBUG(1, ("talloc_asprintf failed.\n"));
krb5_cc_destroy(kr->ctx, kr->cc);
_exit(-1);
}
size = pack_response_packet(buf, PAM_SUCCESS, PAM_ENV_ITEM, env);
if (size < 0) {
DEBUG(1, ("failed to create response message.\n"));
krb5_cc_destroy(kr->ctx, kr->cc);
_exit(-1);
}
kerr = 0;
childfailed:
if (kerr != 0 ) {
krb5_error_msg = krb5_get_error_message(krb5_error_ctx, kerr);
size = pack_response_packet(buf, pam_status, PAM_USER_INFO,
krb5_error_msg);
if (size < 0) {
DEBUG(1, ("failed to create response message.\n"));
krb5_cc_destroy(kr->ctx, kr->cc);
_exit(-1);
}
krb5_free_error_message(krb5_error_ctx, krb5_error_msg);
}
ret = write(fd, buf, size);
if (ret == -1) {
DEBUG(1, ("write failed [%d][%s].\n", errno, strerror(errno)));
krb5_cc_destroy(kr->ctx, kr->cc);
_exit(ret);
}
krb5_cc_close(kr->ctx, kr->cc);
_exit(0);
}
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