1 files changed, 212 insertions, 1 deletions

diff --git a/src/providers/ad/ad_access.c b/src/providers/ad/ad_access.c
index 51c872c3b..c16f04942 100644
--- a/src/providers/ad/ad_access.c
+++ b/src/providers/ad/ad_access.c
@@ -33,6 +33,196 @@ ad_access_done(struct tevent_req *req);
 static errno_t
 ad_access_step(struct tevent_req *req, struct sdap_id_conn_ctx *conn);
 
+/*
+ * More advanced format can be used to restrict the filter to a specific
+ * domain or a specific forest. This format is KEYWORD:NAME:FILTER
+ *
+ *  KEYWORD can be one of DOM or FOREST
+ *      KEYWORD can be missing
+ *  NAME is a label.
+ *      - if KEYWORD equals DOM or missing completely, the filter is applied
+ *        for users from domain named NAME only
+ *      - if KEYWORD equals FOREST, the filter is applied on users from
+ *        forest named NAME only
+ *  examples of valid filters are:
+ *      apply filter on domain called dom1 only:
+ *          dom1:(memberOf=cn=admins,ou=groups,dc=dom1,dc=com)
+ *      apply filter on domain called dom2 only:
+ *          DOM:dom2:(memberOf=cn=admins,ou=groups,dc=dom2,dc=com)
+ *      apply filter on forest called EXAMPLE.COM only:
+ *          FOREST:EXAMPLE.COM:(memberOf=cn=admins,ou=groups,dc=example,dc=com)
+ *
+ * If any of the extended formats are used, the filter MUST be enclosed
+ * already.
+ */
+
+/* From least specific */
+#define AD_FILTER_GENERIC 0x01
+#define AD_FILTER_FOREST  0x02
+#define AD_FILTER_DOMAIN  0x04
+
+#define KW_FOREST "FOREST"
+#define KW_DOMAIN "DOM"
+
+/* parse filter in the format domain_name:filter */
+static errno_t
+parse_sub_filter(TALLOC_CTX *mem_ctx, const char *full_filter,
+                 char **filter, char **sub_name, int *flags,
+                 const int flagconst)
+{
+    char *specdelim;
+
+    specdelim = strchr(full_filter, ':');
+    if (specdelim == NULL) return EINVAL;
+
+    /* Make sure the filter is already enclosed in brackets */
+    if (*(specdelim+1) != '(') return EINVAL;
+
+    *sub_name = talloc_strndup(mem_ctx, full_filter, specdelim - full_filter);
+    *filter = talloc_strdup(mem_ctx, specdelim+1);
+    if (*sub_name == NULL || *filter == NULL) return ENOMEM;
+
+    *flags = flagconst;
+    return EOK;
+}
+
+static inline errno_t
+parse_dom_filter(TALLOC_CTX *mem_ctx, const char *dom_filter,
+                 char **filter, char **domname, int *flags)
+{
+    return parse_sub_filter(mem_ctx, dom_filter, filter, domname,
+                            flags, AD_FILTER_DOMAIN);
+}
+
+static inline errno_t
+parse_forest_filter(TALLOC_CTX *mem_ctx, const char *forest_filter,
+                    char **filter, char **forest_name, int *flags)
+{
+    return parse_sub_filter(mem_ctx, forest_filter, filter, forest_name,
+                            flags, AD_FILTER_FOREST);
+}
+
+
+static errno_t
+parse_filter(TALLOC_CTX *mem_ctx, const char *full_filter,
+             char **filter, char **spec, int *flags)
+{
+    char *kwdelim, *specdelim;
+
+    if (filter == NULL || spec == NULL || flags == NULL) return EINVAL;
+
+    kwdelim = strchr(full_filter, ':');
+    if (kwdelim != NULL) {
+        specdelim = strchr(kwdelim+1, ':');
+
+        if (specdelim == NULL) {
+            /* There is a single keyword. Treat it as a domain name */
+            return parse_dom_filter(mem_ctx, full_filter, filter, spec, flags);
+        } else if (strncmp(full_filter, "DOM", kwdelim-full_filter) == 0) {
+            /* The format must be DOM:domain_name:filter */
+            if (specdelim && specdelim-kwdelim <= 1) {
+                /* Check if there is some domain_name */
+                return EINVAL;
+            }
+
+            return parse_dom_filter(mem_ctx, kwdelim + 1, filter, spec, flags);
+        } else if (strncmp(full_filter, "FOREST", kwdelim-full_filter) == 0) {
+            /* The format must be FOREST:forest_name:filter */
+            if (specdelim && specdelim-kwdelim <= 1) {
+                /* Check if there is some domain_name */
+                return EINVAL;
+            }
+
+            return parse_forest_filter(mem_ctx, kwdelim + 1,
+                                       filter, spec, flags);
+        }
+
+        /* Malformed option */
+        DEBUG(SSSDBG_CRIT_FAILURE,
+              ("Keyword in filter [%s] did not match expected format\n",
+               full_filter));
+        return EINVAL;
+    }
+
+    /* No keyword. Easy. */
+    *filter = talloc_strdup(mem_ctx, full_filter);
+    if (*filter == NULL) return ENOMEM;
+
+    *spec = NULL;
+    *flags = AD_FILTER_GENERIC;
+    return EOK;
+}
+
+static errno_t
+ad_parse_access_filter(TALLOC_CTX *mem_ctx,
+                       struct sss_domain_info *dom,
+                       const char *filter_list,
+                       char **_filter)
+{
+    char **filters;
+    int nfilters;
+    errno_t ret;
+    char *best_match;
+    int best_flags;
+    char *filter;
+    char *spec;
+    int flags;
+    TALLOC_CTX *tmp_ctx;
+
+    tmp_ctx = talloc_new(mem_ctx);
+    if (tmp_ctx == NULL) {
+        ret = ENOMEM;
+        goto done;
+    }
+
+    ret = split_on_separator(tmp_ctx, filter_list, '?', true, true,
+                             &filters, &nfilters);
+    if (ret != EOK) {
+        DEBUG(SSSDBG_CRIT_FAILURE,
+              ("Cannot parse the list of ad_access_filters\n"));
+        goto done;
+    }
+
+    best_match = NULL;
+    best_flags = 0;
+    for (int i=0; i < nfilters; i++) {
+        ret = parse_filter(tmp_ctx, filters[i], &filter, &spec, &flags);
+        if (ret != EOK) {
+            /* Skip the faulty filter. At worst, the user won't be
+             * allowed access */
+            DEBUG(SSSDBG_MINOR_FAILURE, ("Access filter [%s] could not be "
+                  "parsed, skipping\n", filters[i]));
+            continue;
+        }
+
+        if (flags & AD_FILTER_DOMAIN && strcasecmp(spec, dom->name) != 0) {
+            /* If the filter specifies a domain, it must match the
+             * domain the user comes from
+             */
+            continue;
+        }
+
+        if (flags & AD_FILTER_FOREST && strcasecmp(spec, dom->forest) != 0) {
+            /* If the filter specifies a forest, it must match the
+             * forest the user comes from
+             */
+            continue;
+        }
+
+        if (flags > best_flags) {
+            best_flags = flags;
+            best_match = filter;
+        }
+    }
+
+    ret = EOK;
+    /* Make sure the result is enclosed in brackets */
+    *_filter = sdap_get_access_filter(mem_ctx, best_match);
+done:
+    talloc_free(tmp_ctx);
+    return ret;
+}
+
 struct ad_access_state {
     struct tevent_context *ev;
     struct ad_access_ctx *ctx;
@@ -40,6 +230,7 @@ struct ad_access_state {
     struct be_ctx *be_ctx;
     struct sss_domain_info *domain;
 
+    char *filter;
     struct sdap_id_conn_ctx **clist;
     int cindex;
 };
@@ -67,6 +258,14 @@ ad_access_send(TALLOC_CTX *mem_ctx,
     state->be_ctx = be_ctx;
     state->domain = domain;
 
+    ret = ad_parse_access_filter(state, domain, ctx->sdap_access_ctx->filter,
+                                 &state->filter);
+    if (ret != EOK) {
+        DEBUG(SSSDBG_CRIT_FAILURE, ("Could not determine the best filter\n"));
+        ret = ERR_ACCESS_DENIED;
+        goto done;
+    }
+
     state->clist = talloc_zero_array(state, struct sdap_id_conn_ctx *, 3);
     if (state->clist == NULL) {
         ret = ENOMEM;
@@ -106,13 +305,25 @@ ad_access_step(struct tevent_req *req, struct sdap_id_conn_ctx *conn)
 {
     struct tevent_req *subreq;
     struct ad_access_state *state;
+    struct sdap_access_ctx *req_ctx;
 
     state = tevent_req_data(req, struct ad_access_state);
 
+    req_ctx = talloc(state, struct sdap_access_ctx);
+    if (req_ctx == NULL) {
+        return ENOMEM;
+    }
+    req_ctx->id_ctx = state->ctx->sdap_access_ctx->id_ctx;
+    req_ctx->filter = state->filter;
+    memcpy(&req_ctx->access_rule,
+           state->ctx->sdap_access_ctx->access_rule,
+           sizeof(int) * LDAP_ACCESS_LAST);
+
     subreq = sdap_access_send(req, state->ev, state->be_ctx,
-                              state->domain, state->ctx->sdap_access_ctx,
+                              state->domain, req_ctx,
                               conn, state->pd);
     if (req == NULL) {
+        talloc_free(req_ctx);
         return ENOMEM;
     }
     tevent_req_set_callback(subreq, ad_access_done, req);