From 3612c73e7957721bcbf31d0118e2ac210eb46b88 Mon Sep 17 00:00:00 2001
From: Pierre Ossman <pierre@ossman.eu>
Date: Wed, 22 Dec 2010 22:29:03 +0100
Subject: Add host access control support

https://fedorahosted.org/sssd/ticket/746
---
 src/providers/ldap/sdap_access.c | 146 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 146 insertions(+)

(limited to 'src/providers/ldap/sdap_access.c')

diff --git a/src/providers/ldap/sdap_access.c b/src/providers/ldap/sdap_access.c
index 5a6b4a5d..9b598bc5 100644
--- a/src/providers/ldap/sdap_access.c
+++ b/src/providers/ldap/sdap_access.c
@@ -85,6 +85,17 @@ static struct tevent_req *sdap_access_service_send(
 
 static void sdap_account_expired_done(struct tevent_req *subreq);
 
+static errno_t sdap_access_host_recv(struct tevent_req *req,
+                                        int *pam_status);
+static void sdap_access_host_done(struct tevent_req *subreq);
+
+static struct tevent_req *sdap_access_host_send(
+        TALLOC_CTX *mem_ctx,
+        struct tevent_context *ev,
+        struct sdap_access_ctx *access_ctx,
+        struct pam_data *pd,
+        struct ldb_message *user_entry);
+
 static void sdap_access_done(struct tevent_req *req);
 void sdap_pam_access_handler(struct be_req *breq)
 {
@@ -259,6 +270,18 @@ static errno_t select_next_rule(struct tevent_req *req)
             tevent_req_set_callback(subreq, sdap_access_service_done, req);
             return EOK;
 
+        case LDAP_ACCESS_HOST:
+            subreq = sdap_access_host_send(state, state->ev,
+                                              state->access_ctx,
+                                              state->pd,
+                                              state->user_entry);
+            if (subreq == NULL) {
+                DEBUG(1, ("sdap_access_host_send failed.\n"));
+                return ENOMEM;
+            }
+            tevent_req_set_callback(subreq, sdap_access_host_done, req);
+            return EOK;
+
         default:
             DEBUG(1, ("Unexpected access rule type. Access denied.\n"));
     }
@@ -1057,6 +1080,129 @@ static void sdap_access_service_done(struct tevent_req *subreq)
     return;
 }
 
+struct sdap_access_host_ctx {
+    int pam_status;
+};
+
+static struct tevent_req *sdap_access_host_send(
+        TALLOC_CTX *mem_ctx,
+        struct tevent_context *ev,
+        struct sdap_access_ctx *access_ctx,
+        struct pam_data *pd,
+        struct ldb_message *user_entry)
+{
+    errno_t ret;
+    struct tevent_req *req;
+    struct sdap_access_host_ctx *state;
+    struct ldb_message_element *el;
+    unsigned int i;
+    char *host;
+    char hostname[HOST_NAME_MAX+1];
+
+    req = tevent_req_create(mem_ctx, &state, struct sdap_access_host_ctx);
+    if (!req) {
+        return NULL;
+    }
+
+    state->pam_status = PAM_PERM_DENIED;
+
+    el = ldb_msg_find_element(user_entry, SYSDB_AUTHORIZED_HOST);
+    if (!el || el->num_values == 0) {
+        DEBUG(1, ("Missing hosts. Access denied\n"));
+        ret = EOK;
+        goto done;
+    }
+
+    if (gethostname(hostname, sizeof(hostname)) == -1) {
+        DEBUG(1, ("Unable to get system hostname. Access denied\n"));
+        ret = EOK;
+        goto done;
+    }
+
+    /* FIXME: PADL's pam_ldap also calls gethostbyname() on the hostname
+     *        in some attempt to get aliases and/or FQDN for the machine.
+     *        Not sure this is a good idea, but we might want to add it in
+     *        order to be compatible...
+     */
+
+    for (i = 0; i < el->num_values; i++) {
+        host = (char *)el->values[i].data;
+        if (host[0] == '!' &&
+                strcasecmp(hostname, host+1) == 0) {
+            /* This host is explicitly denied */
+            state->pam_status = PAM_PERM_DENIED;
+            DEBUG(4, ("Access denied by [%s]\n", host));
+            /* A denial trumps all. Break here */
+            break;
+
+        } else if (strcasecmp(hostname, host) == 0) {
+            /* This host is explicitly allowed */
+            state->pam_status = PAM_SUCCESS;
+            DEBUG(4, ("Access granted for [%s]\n", host));
+            /* We still need to loop through to make sure
+             * that it's not also explicitly denied
+             */
+        } else if (strcmp("*", host) == 0) {
+            /* This user has access to all hosts */
+            state->pam_status = PAM_SUCCESS;
+            DEBUG(4, ("Access granted to all hosts\n"));
+            /* We still need to loop through to make sure
+             * that it's not also explicitly denied
+             */
+        }
+    }
+
+    if (state->pam_status != PAM_SUCCESS) {
+        DEBUG(4, ("No matching host rule found\n"));
+    }
+
+    ret = EOK;
+
+done:
+    if (ret == EOK) {
+        tevent_req_done(req);
+    } else {
+        tevent_req_error(req, ret);
+    }
+    tevent_req_post(req, ev);
+
+    return req;
+}
+
+static errno_t sdap_access_host_recv(struct tevent_req *req,
+                                        int *pam_status)
+{
+    struct sdap_access_host_ctx *state =
+            tevent_req_data(req, struct sdap_access_host_ctx);
+
+    TEVENT_REQ_RETURN_ON_ERROR(req);
+
+    *pam_status = state->pam_status;
+
+    return EOK;
+}
+
+static void sdap_access_host_done(struct tevent_req *subreq)
+{
+    errno_t ret;
+    struct tevent_req *req = tevent_req_callback_data(subreq, struct tevent_req);
+    struct sdap_access_req_ctx *state =
+            tevent_req_data(req, struct sdap_access_req_ctx);
+
+    ret = sdap_access_host_recv(subreq, &state->pam_status);
+    talloc_zfree(subreq);
+    if (ret != EOK) {
+        DEBUG(1, ("Error retrieving access check result.\n"));
+        state->pam_status = PAM_SYSTEM_ERR;
+        tevent_req_error(req, ret);
+        return;
+    }
+
+    next_access_rule(req);
+
+    return;
+}
+
 static errno_t sdap_access_recv(struct tevent_req *req, int *pam_status)
 {
     struct sdap_access_req_ctx *state =
-- 
cgit