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-rw-r--r--server/providers/krb5/krb5_auth.c567
1 files changed, 567 insertions, 0 deletions
diff --git a/server/providers/krb5/krb5_auth.c b/server/providers/krb5/krb5_auth.c
new file mode 100644
index 000000000..5206bd088
--- /dev/null
+++ b/server/providers/krb5/krb5_auth.c
@@ -0,0 +1,567 @@
+/*
+ SSSD
+
+ Kerberos 5 Backend Module
+
+ 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 <errno.h>
+#include <sys/time.h>
+#include <krb5/krb5.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <pwd.h>
+
+#include <security/pam_modules.h>
+
+#include "util/util.h"
+#include "providers/dp_backend.h"
+#include "db/sysdb.h"
+#include "../sss_client/sss_cli.h"
+#include "krb5_plugin/sssd_krb5_locator_plugin.h"
+#include "providers/krb5/krb5_auth.h"
+
+static void fd_nonblocking(int fd) {
+ int flags;
+
+ flags = fcntl(fd, F_GETFL, 0);
+ if (flags == -1) {
+ DEBUG(1, ("F_GETFL failed [%d][%s].\n", errno, strerror(errno)));
+ return;
+ }
+
+ if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1) {
+ DEBUG(1, ("F_SETFL failed [%d][%s].\n", errno, strerror(errno)));
+ }
+
+ return;
+}
+
+static void krb5_cleanup(struct krb5_req *kr)
+{
+ if (kr == NULL) return;
+
+ /* FIXME: is it safe to drop the "!= NULL" checks? */
+ if (kr->options != NULL)
+ krb5_get_init_creds_opt_free(kr->ctx, kr->options);
+ if (kr->creds != NULL)
+ krb5_free_cred_contents(kr->ctx, kr->creds);
+ if (kr->name != NULL)
+ krb5_free_unparsed_name(kr->ctx, kr->name);
+ if (kr->princ != NULL)
+ krb5_free_principal(kr->ctx, kr->princ);
+ if (kr->cc != NULL)
+ krb5_cc_close(kr->ctx, kr->cc);
+ if (kr->ctx != NULL)
+ krb5_free_context(kr->ctx);
+
+ talloc_free(kr);
+}
+
+static int krb5_setup(struct be_req *req, struct krb5_req **krb5_req)
+{
+ struct krb5_req *kr = NULL;
+ struct krb5_ctx *krb5_ctx;
+ struct pam_data *pd;
+ krb5_error_code kerr = 0;
+ char *user_princ_str = NULL;
+
+ pd = talloc_get_type(req->req_data, struct pam_data);
+
+ krb5_ctx = talloc_get_type(req->be_ctx->pvt_auth_data, struct krb5_ctx);
+
+ kr = talloc_zero(req, struct krb5_req);
+ if (kr == NULL) {
+ DEBUG(1, ("talloc failed.\n"));
+ kerr = ENOMEM;
+ goto failed;
+ }
+
+ kr->pd = pd;
+ kr->req = req;
+
+ kerr = krb5_init_context(&kr->ctx);
+ if (kerr != 0) {
+ KRB5_DEBUG(1, kerr);
+ goto failed;
+ }
+
+/* TODO: try to read user principal from id backend, use user + realm as a
+ fallback */
+ if (kr->pd->user != NULL && krb5_ctx->realm != NULL) {
+ user_princ_str = talloc_asprintf(kr, "%s@%s", kr->pd->user,
+ krb5_ctx->realm);
+ }
+ if (user_princ_str == NULL) {
+ DEBUG(1, ("talloc_asprintf failed.\n"));
+ kerr = ENOMEM;
+ goto failed;
+ }
+
+ kerr = krb5_parse_name(kr->ctx, user_princ_str, &kr->princ);
+ if (kerr != 0) {
+ KRB5_DEBUG(1, kerr);
+ goto failed;
+ }
+
+ kerr = krb5_unparse_name(kr->ctx, kr->princ, &kr->name);
+ if (kerr != 0) {
+ KRB5_DEBUG(1, kerr);
+ goto failed;
+ }
+
+ kr->creds = talloc_zero(kr, krb5_creds);
+ if (kr->creds == NULL) {
+ DEBUG(1, ("talloc_zero failed.\n"));
+ kerr = ENOMEM;
+ goto failed;
+ }
+
+ kerr = krb5_get_init_creds_opt_alloc(kr->ctx, &kr->options);
+ if (kerr != 0) {
+ KRB5_DEBUG(1, kerr);
+ goto failed;
+ }
+
+/* TODO: set options, e.g.
+ * krb5_get_init_creds_opt_set_tkt_life
+ * krb5_get_init_creds_opt_set_renew_life
+ * krb5_get_init_creds_opt_set_forwardable
+ * krb5_get_init_creds_opt_set_proxiable
+ * krb5_get_init_creds_opt_set_etype_list
+ * krb5_get_init_creds_opt_set_address_list
+ * krb5_get_init_creds_opt_set_preauth_list
+ * krb5_get_init_creds_opt_set_salt
+ * krb5_get_init_creds_opt_set_change_password_prompt
+ * krb5_get_init_creds_opt_set_pa
+ */
+
+ *krb5_req = kr;
+ return EOK;
+
+failed:
+ krb5_cleanup(kr);
+
+ return kerr;
+}
+
+/* TODO: remove later
+ * These functions are available in the latest tevent and are the ones that
+ * should be used as tevent_req is rightfully opaque there */
+#ifndef tevent_req_data
+#define tevent_req_data(req, type) ((type *)req->private_state)
+#endif
+
+#ifndef tevent_req_set_callback
+#define tevent_req_set_callback(req, func, data) \
+ do { req->async.fn = func; req->async.private_data = data; } while(0)
+#endif
+
+#ifndef tevent_req_callback_data
+#define tevent_req_callback_data(req, type) ((type *)req->async.private_data)
+#endif
+
+static void wait_for_child_handler(struct tevent_context *ev,
+ struct tevent_signal *sige, int signum,
+ int count, void *__siginfo, void *pvt)
+{
+ int ret;
+ int child_status;
+ siginfo_t *siginfo = (siginfo_t *)__siginfo;
+
+ errno = 0;
+ do {
+ ret = waitpid(siginfo->si_pid, &child_status, WNOHANG);
+ } while (ret == -1 && errno == EINTR);
+ if (ret == siginfo->si_pid) {
+ DEBUG(4, ("child status [%d].\n", child_status));
+ if (WEXITSTATUS(child_status) != 0) {
+ DEBUG(1, ("child failed.\n"));
+ }
+ } else if (ret == 0) {
+ DEBUG(1, ("waitpid did not found a child with changed status.\n", ret));
+ } else if (ret >= 0 && ret != siginfo->si_pid) {
+ DEBUG(1, ("waitpid returned wrong child pid [%d], continue waiting.\n", ret));
+ } else if (ret == -1 && errno == ECHILD) {
+ DEBUG(1, ("no child with pid [%d].\n", siginfo->si_pid));
+ } else {
+ DEBUG(1, ("waitpid failed [%s].\n", strerror(errno)));
+ }
+
+ return;
+}
+
+static int fork_tgt_req_child(struct krb5_req *kr)
+{
+ int pipefd[2];
+ pid_t pid;
+ int ret;
+
+ ret = pipe(pipefd);
+ if (ret == -1) {
+ DEBUG(1, ("pipe failed [%d][%s].\n", errno, strerror(errno)));
+ return -1;
+ }
+ pid = fork();
+
+ if (pid == 0) { /* child */
+ close(pipefd[0]);
+ tgt_req_child(pipefd[1], kr);
+ } else if (pid > 0) { /* parent */
+ kr->child_pid = pid;
+ kr->fd = pipefd[0];
+ close(pipefd[1]);
+
+ fd_nonblocking(kr->fd);
+
+ } else { /* error */
+ DEBUG(1, ("fork failed [%d][%s].\n", errno, strerror(errno)));
+ return -1;
+ }
+
+ return EOK;
+}
+
+
+struct read_pipe_state {
+ int fd;
+ uint8_t *buf;
+ size_t len;
+};
+
+static void read_pipe_done(struct tevent_context *ev, struct tevent_fd *fde,
+ uint16_t flags, void *pvt);
+
+static struct tevent_req *read_pipe_send(TALLOC_CTX *memctx,
+ struct tevent_context *ev,
+ int fd)
+{
+ struct tevent_req *req;
+ struct read_pipe_state *state;
+ struct tevent_fd *fde;
+
+
+ req = tevent_req_create(memctx, &state, struct read_pipe_state);
+ if (req == NULL) return NULL;
+
+ state->fd = fd;
+ state->buf = talloc_array(state, uint8_t, MAX_CHILD_MSG_SIZE);
+ if (state->buf == NULL) goto fail;
+
+ fde = tevent_add_fd(ev, state, fd, TEVENT_FD_READ,
+ read_pipe_done, req);
+ if (fde == NULL) {
+ DEBUG(1, ("tevent_add_fd failed.\n"));
+ goto fail;
+ }
+
+ return req;
+
+fail:
+ talloc_zfree(req);
+ return NULL;
+}
+
+static void read_pipe_done(struct tevent_context *ev, struct tevent_fd *fde,
+ uint16_t flags, void *pvt)
+{
+ ssize_t size;
+ struct tevent_req *req = talloc_get_type(pvt, struct tevent_req);
+ struct read_pipe_state *state = tevent_req_data(req, struct read_pipe_state);
+
+ if (flags & TEVENT_FD_WRITE) {
+ DEBUG(1, ("client_response_handler called with TEVENT_FD_WRITE, this should not happen.\n"));
+ tevent_req_error(req, EINVAL);
+ return;
+ }
+
+ size = read(state->fd, state->buf, talloc_get_size(state->buf));
+ if (size == -1) {
+ if (errno == EAGAIN || errno == EINTR) return;
+ DEBUG(1, ("read failed [%d][%s].\n", errno, strerror(errno)));
+ tevent_req_error(req, errno);
+ return;
+ }
+ state->len = size;
+
+ tevent_req_done(req);
+ return;
+}
+
+static ssize_t read_pipe_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
+ uint8_t **buf, uint64_t *error) {
+ struct read_pipe_state *state = tevent_req_data(req,
+ struct read_pipe_state);
+ enum tevent_req_state tstate;
+
+ if (tevent_req_is_error(req, &tstate, error)) {
+ return -1;
+ }
+
+ *buf = talloc_move(mem_ctx, &state->buf);
+ return state->len;
+}
+
+struct tgt_req_state {
+ struct krb5_req *kr;
+ ssize_t len;
+ uint8_t *buf;
+};
+
+static void tgt_req_done(struct tevent_req *subreq);
+
+static struct tevent_req *tgt_req_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
+ struct krb5_req *kr)
+{
+ int ret;
+ struct tevent_req *req;
+ struct tevent_req *subreq;
+ struct tgt_req_state *state;
+
+ ret = fork_tgt_req_child(kr);
+ if (ret != EOK) {
+ DEBUG(1, ("fork_tgt_req_child failed.\n"));
+ return NULL;
+ }
+
+ req = tevent_req_create(mem_ctx, &state, struct tgt_req_state);
+ if (req == NULL) {
+ return NULL;
+ }
+
+ state->kr = kr;
+
+ subreq = read_pipe_send(state, ev, kr->fd);
+ if (tevent_req_nomem(subreq, req)) {
+ return tevent_req_post(req, ev);
+ }
+ tevent_req_set_callback(subreq, tgt_req_done, req);
+ return req;
+}
+
+static void tgt_req_done(struct tevent_req *subreq)
+{
+ struct tevent_req *req = tevent_req_callback_data(subreq,
+ struct tevent_req);
+ struct tgt_req_state *state = tevent_req_data(req, struct tgt_req_state);
+ uint64_t error;
+
+ state->len = read_pipe_recv(subreq, state, &state->buf, &error);
+ talloc_zfree(subreq);
+ close(state->kr->fd);
+ if (state->len == -1) {
+ tevent_req_error(req, error);
+ return;
+ }
+
+ tevent_req_done(req);
+ return;
+}
+
+static ssize_t tgt_req_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
+ uint8_t **buf, uint64_t *error) {
+ struct tgt_req_state *state = tevent_req_data(req, struct tgt_req_state);
+ enum tevent_req_state tstate;
+
+ if (tevent_req_is_error(req, &tstate, error)) {
+ return -1;
+ }
+
+ *buf = talloc_move(mem_ctx, &state->buf);
+ return state->len;
+}
+
+static void krb5_pam_handler_done(struct tevent_req *req);
+
+static void krb5_pam_handler(struct be_req *be_req)
+{
+ struct krb5_req *kr = NULL;
+ struct tevent_req *req;
+ int ret;
+ struct pam_data *pd;
+ int pam_status=PAM_SYSTEM_ERR;
+
+ pd = talloc_get_type(be_req->req_data, struct pam_data);
+
+ if (pd->cmd != SSS_PAM_AUTHENTICATE) {
+ DEBUG(4, ("krb5 does not handles pam task %d.\n", pd->cmd));
+ pam_status = PAM_SUCCESS;
+ goto done;
+ }
+
+ ret = krb5_setup(be_req, &kr);
+ if (ret != EOK) {
+ DEBUG(1, ("krb5_setup failed.\n"));
+ goto done;
+ }
+
+ req = tgt_req_send(be_req, be_req->be_ctx->ev, kr);
+ if (req == NULL) {
+ DEBUG(1, ("tgt_req_send failed.\n"));
+ goto done;
+ }
+
+ tevent_req_set_callback(req, krb5_pam_handler_done, kr);
+ return;
+
+done:
+ krb5_cleanup(kr);
+
+ pd->pam_status = pam_status;
+
+ be_req->fn(be_req, pam_status, NULL);
+}
+
+static void krb5_pam_handler_done(struct tevent_req *req)
+{
+ struct krb5_req *kr = tevent_req_callback_data(req, struct krb5_req);
+ struct pam_data *pd = kr->pd;
+ struct be_req *be_req = kr->req;
+ struct krb5_ctx *krb5_ctx = talloc_get_type(be_req->be_ctx->pvt_auth_data,
+ struct krb5_ctx);
+ struct tgt_req_state *state = tevent_req_data(req, struct tgt_req_state);
+ int ret;
+ uint8_t *buf;
+ ssize_t len;
+ uint64_t error;
+ int p;
+ int32_t *msg_status;
+ int32_t *msg_type;
+ int32_t *msg_len;
+
+ pd->pam_status = PAM_SYSTEM_ERR;
+ krb5_cleanup(kr);
+
+ len = tgt_req_recv(req, state, &buf, &error);
+ talloc_zfree(req);
+ if (len == -1) {
+ DEBUG(1, ("tgt_req request failed\n"));
+ goto done;
+ }
+
+ if ((size_t) len < 3*sizeof(int32_t)) {
+ DEBUG(1, ("message too short.\n"));
+ goto done;
+ }
+
+ p=0;
+ msg_status = ((int32_t *)(buf+p));
+ p += sizeof(int32_t);
+
+ msg_type = ((int32_t *)(buf+p));
+ p += sizeof(int32_t);
+
+ msg_len = ((int32_t *)(buf+p));
+ p += sizeof(int32_t);
+
+ DEBUG(4, ("child response [%d][%d][%d].\n", *msg_status, *msg_type,
+ *msg_len));
+
+ if ((p + *msg_len) != len) {
+ DEBUG(1, ("message format error.\n"));
+ goto done;
+ }
+
+ ret=pam_add_response(kr->pd, *msg_type, *msg_len, &buf[p]);
+ if (ret != EOK) {
+ DEBUG(1, ("pam_add_response failed.\n"));
+ goto done;
+ }
+
+ pd->pam_status = *msg_status;
+
+done:
+ be_req->fn(be_req, pd->pam_status, NULL);
+}
+
+
+struct be_auth_ops krb5_auth_ops = {
+ .pam_handler = krb5_pam_handler,
+ .finalize = NULL,
+};
+
+
+int sssm_krb5_auth_init(struct be_ctx *bectx, struct be_auth_ops **ops,
+ void **pvt_auth_data)
+{
+ struct krb5_ctx *ctx = NULL;
+ bool bool_value = FALSE;
+ char *value = NULL;
+ int ret;
+ struct tevent_signal *sige;
+
+ ctx = talloc_zero(bectx, struct krb5_ctx);
+ if (!ctx) {
+ DEBUG(1, ("talloc failed.\n"));
+ return ENOMEM;
+ }
+
+ ctx->action = INIT_PW;
+
+ ret = confdb_get_string(bectx->cdb, ctx, bectx->conf_path,
+ "krb5KDCIP", NULL, &value);
+ if (ret != EOK) goto fail;
+ if (value == NULL) {
+ DEBUG(2, ("Missing krb5KDCIP, authentication might fail.\n"));
+ } else {
+ ret = setenv(SSSD_KDC, value, 1);
+ if (ret != EOK) {
+ DEBUG(2, ("setenv %s failed, authentication might fail.\n",
+ SSSD_KDC));
+ }
+ }
+ ctx->kdcip = value;
+
+ ret = confdb_get_string(bectx->cdb, ctx, bectx->conf_path,
+ "krb5REALM", NULL, &value);
+ if (ret != EOK) goto fail;
+ if (value == NULL) {
+ DEBUG(4, ("Missing krb5REALM authentication might fail.\n"));
+ } else {
+ ret = setenv(SSSD_REALM, value, 1);
+ if (ret != EOK) {
+ DEBUG(2, ("setenv %s failed, authentication might fail.\n",
+ SSSD_REALM));
+ }
+ }
+ ctx->realm = value;
+
+/* TODO: set options */
+
+ sige = tevent_add_signal(bectx->ev, ctx, SIGCHLD, SA_SIGINFO,
+ wait_for_child_handler, NULL);
+ if (sige == NULL) {
+ DEBUG(1, ("tevent_add_signal failed.\n"));
+ ret = ENOMEM;
+ goto fail;
+ }
+
+
+ *ops = &krb5_auth_ops;
+ *pvt_auth_data = ctx;
+ return EOK;
+
+fail:
+ talloc_free(ctx);
+ return ret;
+}
generated by cgit (git 2.34.1) at 2024-04-30 17:19:32 +0000