PAC responder: add some utility functions

2 files changed, 549 insertions, 0 deletions

diff --git a/src/responder/pac/pacsrv.h b/src/responder/pac/pacsrv.h
index 0dfe7f9e..f0ffea29 100644
--- a/src/responder/pac/pacsrv.h
+++ b/src/responder/pac/pacsrv.h
@@ -21,6 +21,11 @@
 
 #ifndef __PACSRV_H__
 #define __PACSRV_H__
+#include <stdbool.h>
+#include <util/data_blob.h>
+#include <ndr.h>
+#include <gen_ndr/krb5pac.h>
+#include <gen_ndr/ndr_krb5pac.h>
 
 #include <stdint.h>
 #include <sys/un.h>
@@ -33,6 +38,8 @@
 #include "responder/common/responder_packet.h"
 #include "responder/common/responder.h"
 #include "lib/idmap/sss_idmap.h"
+#include "util/sss_nss.h"
+#include "db/sysdb.h"
 
 #define PAC_SBUS_SERVICE_VERSION 0x0001
 #define PAC_SBUS_SERVICE_NAME "pac"
@@ -40,13 +47,61 @@
 #define PAC_PACKET_MAX_RECV_SIZE 1024
 
 struct getent_ctx;
+struct dom_sid;
 
 struct pac_ctx {
     struct resp_ctx *rctx;
+    struct sss_idmap_ctx *idmap_ctx;
+    struct dom_sid *my_dom_sid;
+    struct local_mapping_ranges *range_map;
+};
+
+struct range {
+    uint32_t min;
+    uint32_t max;
+};
+
+struct local_mapping_ranges {
+    struct range local_ids;
+    struct range primary_rids;
+    struct range secondary_rids;
 };
 
 int pac_cmd_execute(struct cli_ctx *cctx);
 
 struct sss_cmd_table *get_pac_cmds(void);
 
+errno_t local_sid_to_id(struct local_mapping_ranges *map, struct dom_sid *sid,
+                        uint32_t *id);
+
+errno_t add_idmap_domain(struct sss_idmap_ctx *idmap_ctx,
+                         struct sysdb_ctx *sysdb,
+                         const char *domain_name,
+                         const char *dom_sid_str);
+
+errno_t domsid_rid_to_uid(struct pac_ctx *pac_ctx,
+                          struct sysdb_ctx *sysdb,
+                          const char *domain_name,
+                          struct dom_sid2 *domsid, uint32_t rid,
+                          uid_t *uid);
+
+errno_t get_my_domain_sid(struct pac_ctx *pac_ctx,
+                          struct sss_domain_info *dom,
+                          struct dom_sid **_sid);
+
+errno_t get_gids_from_pac(TALLOC_CTX *mem_ctx,
+                          struct local_mapping_ranges *range_map,
+                          struct dom_sid *domain_sid,
+                          struct PAC_LOGON_INFO *logon_info,
+                          size_t *_gid_count, gid_t **_gids);
+
+errno_t get_data_from_pac(TALLOC_CTX *mem_ctx,
+                          uint8_t *pac_blob, size_t pac_len,
+                          struct PAC_LOGON_INFO **_logon_info);
+
+errno_t get_pwd_from_pac(TALLOC_CTX *mem_ctx,
+                         struct pac_ctx *pac_ctx,
+                         struct sss_domain_info *dom,
+                         struct PAC_LOGON_INFO *logon_info,
+                         struct passwd **_pwd);
 #endif /* __PACSRV_H__ */
diff --git a/src/responder/pac/pacsrv_utils.c b/src/responder/pac/pacsrv_utils.c
new file mode 100644
index 00000000..43d84121
--- /dev/null
+++ b/src/responder/pac/pacsrv_utils.c
@@ -0,0 +1,494 @@
+/*
+   SSSD
+
+   PAC Responder - utility finctions
+
+   Copyright (C) Sumit Bose <sbose@redhat.com> 2012
+
+   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 <stdbool.h>
+#include <util/data_blob.h>
+#include <gen_ndr/security.h>
+
+#include "util/util.h"
+#include "responder/pac/pacsrv.h"
+
+static errno_t get_rid(struct dom_sid *sid, uint32_t *rid)
+{
+    if (sid == NULL || sid->num_auths < 1 || rid == NULL) {
+        return EINVAL;
+    }
+
+    *rid = sid->sub_auths[sid->num_auths - 1];
+
+    return EOK;
+}
+
+/**
+ * Find the Posix ID to a SID from the local IPA domain
+ */
+errno_t local_sid_to_id(struct local_mapping_ranges *map, struct dom_sid *sid,
+                        uint32_t *id)
+{
+    int ret;
+    uint32_t rid;
+
+    if (map == NULL || sid == NULL || id == NULL) {
+        return EINVAL;
+    }
+
+    ret = get_rid(sid, &rid);
+    if (ret != EOK) {
+        DEBUG(SSSDBG_OP_FAILURE, ("get_rid failed.\n"));
+        return ret;
+    }
+
+    if (rid >= map->primary_rids.min && rid <= map->primary_rids.max) {
+        *id = map->local_ids.min + (rid -  map->primary_rids.min);
+    } else if (rid >= map->secondary_rids.min &&
+               rid <= map->secondary_rids.max) {
+        *id = map->local_ids.min + (rid -  map->secondary_rids.min);
+    } else {
+        return ENOENT;
+    }
+
+    if (*id < map->local_ids.min || *id > map->local_ids.max) {
+        return ERANGE;
+    }
+
+    return EOK;
+}
+
+/**
+ * Add a new remote domain and the corresponding ID range to the context of
+ * the libsss_idmap. Without this it is not possible to find the Posix UID for
+ * a user fo the remote domain.
+ */
+errno_t add_idmap_domain(struct sss_idmap_ctx *idmap_ctx,
+                         struct sysdb_ctx *sysdb,
+                         const char *domain_name,
+                         const char *dom_sid_str)
+{
+    struct sss_idmap_range range;
+    enum idmap_error_code err;
+
+    /* TODO: read range form sysdb if
+     * https://fedorahosted.org/freeipa/ticket/2185 is fixed */
+    range.min = 200000;
+    range.max = 400000;
+
+    err = sss_idmap_add_domain(idmap_ctx, domain_name, dom_sid_str, &range);
+    if (err != IDMAP_SUCCESS) {
+        DEBUG(SSSDBG_OP_FAILURE, ("sss_idmap_add_domain failed.\n"));
+        return EFAULT;
+    }
+
+    return EOK;
+}
+
+/**
+ * Find the corresponding UID for a user from a remote domain based on the
+ * domain SID of the remote domain and the RID of the user.
+ */
+errno_t domsid_rid_to_uid(struct pac_ctx *pac_ctx,
+                          struct sysdb_ctx *sysdb,
+                          const char *domain_name,
+                          struct dom_sid2 *domsid, uint32_t rid,
+                          uid_t *uid)
+{
+    enum idmap_error_code err;
+    char *sid_str = NULL;
+    char *dom_sid_str = NULL;
+    uint32_t id;
+    int ret;
+
+    err = sss_idmap_smb_sid_to_sid(pac_ctx->idmap_ctx, domsid,
+                                   &dom_sid_str);
+    if (err != IDMAP_SUCCESS) {
+        DEBUG(SSSDBG_OP_FAILURE, ("sss_idmap_smb_sid_to_sid failed.\n"));
+        ret = EFAULT;
+        goto done;
+    }
+
+    sid_str = talloc_asprintf(NULL, "%s-%lu", dom_sid_str, (unsigned long) rid);
+    if (sid_str == NULL) {
+        DEBUG(SSSDBG_OP_FAILURE, ("dom_sid_and_rid_string failed.\n"));
+        return ENOMEM;
+    }
+
+    err = sss_idmap_smb_sid_to_sid(pac_ctx->idmap_ctx, domsid, &sid_str);
+    if (err != IDMAP_SUCCESS) {
+        DEBUG(SSSDBG_OP_FAILURE, ("sss_idmap_smb_sid_to_sid failed.\n"));
+        ret = EFAULT;
+        goto done;
+    }
+
+    err = sss_idmap_sid_to_unix(pac_ctx->idmap_ctx, sid_str, &id);
+    if (err == IDMAP_NO_DOMAIN) {
+        ret = add_idmap_domain(pac_ctx->idmap_ctx, sysdb, domain_name,
+                               dom_sid_str);
+        if (ret != EOK) {
+            DEBUG(SSSDBG_OP_FAILURE, ("add_idmap_domain failed.\n"));
+            goto done;
+        }
+
+        err = sss_idmap_sid_to_unix(pac_ctx->idmap_ctx, sid_str, &id);
+        if (err != IDMAP_SUCCESS) {
+            DEBUG(SSSDBG_FATAL_FAILURE, ("sss_idmap_sid_to_unix failed "
+                                         "even in the second attempt.\n"));
+            ret = ENOENT;
+            goto done;
+        }
+    } else if (err != IDMAP_SUCCESS && err != IDMAP_NO_DOMAIN) {
+        DEBUG(SSSDBG_OP_FAILURE, ("sss_idmap_sid_to_unix failed.\n"));
+        ret = EFAULT;
+        goto done;
+    }
+
+    *uid = (uid_t) id;
+
+    ret = EOK;
+
+done:
+    talloc_free(dom_sid_str);
+    talloc_free(sid_str);
+    return ret;
+}
+
+/**
+ * Return information about the local domain from the main PAC responder
+ * context or try to read it from cache and store it in the context.
+ */
+errno_t get_my_domain_sid(struct pac_ctx *pac_ctx,
+                          struct sss_domain_info *dom,
+                          struct dom_sid **_sid)
+{
+    struct sysdb_ctx *sysdb;
+    int ret;
+    struct ldb_dn *basedn;
+    const char *attrs[] = {SYSDB_SUBDOMAIN_ID,
+                           NULL};
+    size_t msgs_count;
+    const char *sid_str;
+    struct ldb_message **msgs;
+    TALLOC_CTX *tmp_ctx = NULL;
+    struct dom_sid *sid = NULL;
+    char *dom_name;
+    enum idmap_error_code err;
+
+    if (pac_ctx->my_dom_sid == NULL) {
+        if (dom->parent != NULL) {
+            sysdb = dom->parent->sysdb;
+            dom_name = dom->parent->name;
+        } else {
+            sysdb = dom->sysdb;
+            dom_name = dom->name;
+        }
+
+        if (sysdb == NULL) {
+            DEBUG(SSSDBG_FATAL_FAILURE, ("Missing sysdb context.\n"));
+            ret = EINVAL;
+            goto done;
+        }
+
+        tmp_ctx = talloc_new(NULL);
+        if (tmp_ctx == NULL) {
+            DEBUG(SSSDBG_OP_FAILURE, ("talloc_new failed.\n"));
+            ret = ENOMEM;
+            goto done;
+        }
+
+        basedn = sysdb_domain_dn(sysdb, tmp_ctx, dom_name);
+        if (basedn == NULL) {
+            ret = ENOMEM;
+            goto done;
+        }
+
+        ret = sysdb_search_entry(tmp_ctx, sysdb, basedn, LDB_SCOPE_BASE, NULL,
+                                 attrs, &msgs_count, &msgs);
+        if (ret != LDB_SUCCESS) {
+            ret = EIO;
+            goto done;
+        }
+
+        if (msgs_count != 1) {
+            DEBUG(SSSDBG_OP_FAILURE, ("Base search returned [%d] results, "
+                                     "expected 1.\n", msgs_count));
+            ret = EINVAL;
+            goto done;
+        }
+
+        sid_str = ldb_msg_find_attr_as_string(msgs[0], SYSDB_SUBDOMAIN_ID, NULL);
+        if (sid_str == NULL) {
+            DEBUG(SSSDBG_OP_FAILURE, ("SID of my domain is not available.\n"));
+            ret = EINVAL;
+            goto done;
+        }
+
+        err = sss_idmap_sid_to_smb_sid(pac_ctx->idmap_ctx, sid_str, &sid);
+        if (err != IDMAP_SUCCESS) {
+            DEBUG(SSSDBG_OP_FAILURE, ("sss_idmap_sid_to_smb_sid failed.\n"));
+            ret = EFAULT;
+            goto done;
+        }
+
+        pac_ctx->my_dom_sid = talloc_memdup(pac_ctx, sid,
+                                            sizeof(struct dom_sid));
+        if (pac_ctx->my_dom_sid == NULL) {
+            DEBUG(SSSDBG_OP_FAILURE, ("talloc_memdup failed.\n"));
+            ret = ENOMEM;
+            goto done;
+        }
+    }
+
+    *_sid = pac_ctx->my_dom_sid;
+
+    ret = EOK;
+
+done:
+    talloc_free(sid);
+    talloc_free(tmp_ctx);
+
+    return ret;
+}
+
+/**
+ * Check if a given SID belongs to a domain identified by the domain SID.
+ */
+bool dom_sid_in_domain(const struct dom_sid *domain_sid,
+                       const struct dom_sid *sid)
+{
+    size_t c;
+
+    if (!domain_sid || !sid) {
+        return false;
+    }
+
+    if (domain_sid->sid_rev_num != sid->sid_rev_num) {
+        return false;
+    }
+
+    for (c = 0; c < 6; c++) {
+        if (domain_sid->id_auth[c] != sid->id_auth[c]) {
+            return false;
+        }
+    }
+
+    if (domain_sid->num_auths > sid->num_auths) {
+        return false;
+    }
+
+    for (c = 0; c < domain_sid->num_auths-1; c++) {
+        if (domain_sid->sub_auths[c] != sid->sub_auths[c]) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+/**
+ * Find all Posix GIDs from a PAC by searching for group SIDs from the local
+ * domain and convert them to GIDs.
+ */
+errno_t get_gids_from_pac(TALLOC_CTX *mem_ctx,
+                          struct local_mapping_ranges *range_map,
+                          struct dom_sid *domain_sid,
+                          struct PAC_LOGON_INFO *logon_info,
+                          size_t *_gid_count, gid_t **_gids)
+{
+    int ret;
+    size_t g = 0;
+    size_t s;
+    struct netr_SamInfo3 *info3;
+    gid_t *gids = NULL;
+
+    info3 = &logon_info->info3;
+
+    if (info3->sidcount == 0) {
+        DEBUG(SSSDBG_TRACE_ALL, ("No extra groups found.\n"));
+        ret = EOK;
+        goto done;
+    }
+
+    gids = talloc_array(mem_ctx, gid_t, info3->sidcount);
+    if (gids == NULL) {
+        DEBUG(SSSDBG_OP_FAILURE, ("talloc_array failed.\n"));
+        ret = ENOMEM;
+        goto done;
+    }
+
+    for(s = 0; s < info3->sidcount; s++) {
+        if (dom_sid_in_domain(domain_sid, info3->sids[s].sid)) {
+            ret = local_sid_to_id(range_map, info3->sids[s].sid, &gids[g]);
+            if (ret != EOK) {
+                DEBUG(SSSDBG_OP_FAILURE, ("get_rid failed.\n"));
+                goto done;
+            }
+            DEBUG(SSSDBG_TRACE_ALL, ("Found extra group "
+                                     "with gid [%d].\n", gids[g]));
+            g++;
+        }
+    }
+
+    ret = EOK;
+
+done:
+    if (ret == EOK) {
+        *_gid_count = g;
+        *_gids = gids;
+    } else {
+        talloc_free(gids);
+    }
+
+    return ret;
+}
+
+/**
+ * Extract the PAC logon data from an NDR blob.
+ */
+errno_t get_data_from_pac(TALLOC_CTX *mem_ctx,
+                          uint8_t *pac_blob, size_t pac_len,
+                          struct PAC_LOGON_INFO **_logon_info)
+{
+    DATA_BLOB blob;
+    struct ndr_pull *ndr_pull;
+    struct PAC_DATA *pac_data;
+    enum ndr_err_code ndr_err;
+    size_t c;
+    int ret;
+
+    blob.data = pac_blob;
+    blob.length = pac_len;
+
+    ndr_pull = ndr_pull_init_blob(&blob, mem_ctx);
+    if (ndr_pull == NULL) {
+        DEBUG(SSSDBG_OP_FAILURE, ("ndr_pull_init_blob failed.\n"));
+        return ENOMEM;
+    }
+    ndr_pull->flags |= LIBNDR_FLAG_REF_ALLOC; /* FIXME: is this really needed ? */
+
+    pac_data = talloc_zero(mem_ctx, struct PAC_DATA);
+    if (pac_data == NULL) {
+        DEBUG(SSSDBG_OP_FAILURE, ("talloc_zero failed.\n"));
+        return ENOMEM;
+    }
+
+    ndr_err = ndr_pull_PAC_DATA(ndr_pull, NDR_SCALARS|NDR_BUFFERS, pac_data);
+    if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+        DEBUG(SSSDBG_OP_FAILURE, ("ndr_pull_PAC_DATA failed [%d]\n", ndr_err));
+        return EBADMSG;
+    }
+
+    for(c = 0; c < pac_data->num_buffers; c++) {
+        if (pac_data->buffers[c].type == PAC_TYPE_LOGON_INFO) {
+            *_logon_info = pac_data->buffers[c].info->logon_info.info;
+
+            return EOK;
+        }
+    }
+
+    ret = EINVAL;
+
+    talloc_free(pac_data);
+    return ret;
+}
+
+/**
+ * Fill up the passwd struct with data from the PAC logon info
+ */
+errno_t get_pwd_from_pac(TALLOC_CTX *mem_ctx,
+                         struct pac_ctx *pac_ctx,
+                         struct sss_domain_info *dom,
+                         struct PAC_LOGON_INFO *logon_info,
+                         struct passwd **_pwd)
+{
+    struct passwd *pwd = NULL;
+    struct netr_SamBaseInfo *base_info;
+    int ret;
+
+    pwd = talloc_zero(mem_ctx, struct passwd);
+    if (pwd == NULL) {
+        DEBUG(SSSDBG_OP_FAILURE, ("talloc_zero failed.\n"));
+        return ENOMEM;
+    }
+
+    base_info = &logon_info->info3.base;
+
+    if (base_info->account_name.size != 0) {
+        pwd->pw_name = talloc_strdup(pwd,
+                                     base_info->account_name.string);
+        if (pwd->pw_name == NULL) {
+            DEBUG(SSSDBG_OP_FAILURE, ("talloc_strdup failed.\n"));
+            ret = ENOMEM;
+            goto done;
+        }
+    } else {
+        DEBUG(SSSDBG_OP_FAILURE, ("Missing account name in PAC.\n"));
+        ret = EINVAL;
+        goto done;
+    }
+
+    if (base_info->rid > 0) {
+        ret = domsid_rid_to_uid(pac_ctx, dom->sysdb, dom->name,
+                                base_info->domain_sid,
+                                base_info->rid, &pwd->pw_uid);
+        if (ret != EOK) {
+            DEBUG(SSSDBG_OP_FAILURE, ("domsid_rid_to_uid failed.\n"));
+            goto done;
+        }
+    } else {
+        DEBUG(SSSDBG_OP_FAILURE, ("Missing user RID in PAC.\n"));
+        ret = EINVAL;
+        goto done;
+    }
+
+    pwd->pw_gid = 0; /* We use MPGs for sub-domains */
+
+    if (base_info->full_name.size != 0) {
+        pwd->pw_gecos = talloc_strdup(pwd, base_info->full_name.string);
+        if (pwd->pw_gecos == NULL) {
+            DEBUG(SSSDBG_OP_FAILURE, ("talloc_strdup failed.\n"));
+            ret = ENOMEM;
+            goto done;
+        }
+    } else {
+        DEBUG(SSSDBG_OP_FAILURE, ("Missing full name in PAC, "
+                                  "gecos field will by empty.\n "));
+    }
+
+    if (dom->subdomain_homedir) {
+        pwd->pw_dir = expand_homedir_template(pwd, dom->subdomain_homedir,
+                                              pwd->pw_name, pwd->pw_uid,
+                                              dom->name);
+        if (pwd->pw_dir == NULL) {
+            ret = ENOMEM;
+            goto done;
+        }
+    }
+
+    pwd->pw_shell = NULL; /* Using default */
+
+    *_pwd = pwd;
+
+    ret = EOK;
+
+done:
+    if (ret != EOK) {
+        talloc_free(pwd);
+    }
+
+    return ret;
+}