Ticket 50790 - Add result text when filter is invalid

Bug Description: As a result of the change in 50727
we need to communicate to users/admins when queries they issue
may be incomplete due to rfc compliance of filter processing.

Fix Description: When we use idl_alloc(0) on attributes, we set
a result text (if none already set) warning that the result set
may be incomplete.

https://pagure.io/389-ds-base/issue/50790

Author: William Brown <william@blackhats.net.au>

Review by: tbordaz (Thanks!)

ldap/servers/slapd/pblock.c

@@ -4369,6 +4369,15 @@ slapi_pblock_set_flag_operation_notes(Slapi_PBlock *pb, uint32_t opflag) {
     pb->pb_intop->pb_operation_notes |= opflag;
 }
 
+/* Set result text if it's NULL */
+void
+slapi_pblock_set_result_text_if_empty(Slapi_PBlock *pb, char *text) {
+    _pblock_assert_pb_intop(pb);
+    if (pb->pb_intop->pb_result_text == NULL) {
+        pb->pb_intop->pb_result_text = slapi_ch_strdup(text);
+    }
+}
+
 /*
  * Clear and then set the bind DN and related credentials for the
  * connection `conn'.

ldap/servers/slapd/schema.c

@@ -760,7 +760,7 @@ slapi_filter_schema_check_inner(Slapi_Filter *f) {
  *
  */
 Slapi_Filter_Result
-slapi_filter_schema_check(Slapi_Filter *f, Slapi_Filter_Policy fp) {
+slapi_filter_schema_check(Slapi_PBlock *pb, Slapi_Filter *f, Slapi_Filter_Policy fp) {
     if (f == NULL) {
         return FILTER_SCHEMA_FAILURE;
     }
@@ -780,6 +780,9 @@ slapi_filter_schema_check(Slapi_Filter *f, Slapi_Filter_Policy fp) {
     /* If any warning occured, ensure we fail it. */
     if (fp == FILTER_POLICY_STRICT && r != FILTER_SCHEMA_SUCCESS) {
         r = FILTER_SCHEMA_FAILURE;
+    } else if (fp == FILTER_POLICY_PROTECT && r == FILTER_SCHEMA_WARNING) {
+        /* Or, make sure we setup text to warn the user submitting the query */
+        slapi_pblock_set_result_text_if_empty(pb, "Invalid attribute in filter - results may not be complete.");
     }
     return r;
 }

ldap/servers/slapd/search.c

@@ -203,7 +203,7 @@ do_search(Slapi_PBlock *pb)
      * or reject. A question is the location of this and if we should try to work with
      * internal searches too ...
      */
-    Slapi_Filter_Result r = slapi_filter_schema_check(filter, config_get_verify_filter_schema());
+    Slapi_Filter_Result r = slapi_filter_schema_check(pb, filter, config_get_verify_filter_schema());
     if (r == FILTER_SCHEMA_FAILURE) {
         char *errtxt = "The filter provided contains invalid attributes not found in schema";
         err = LDAP_UNWILLING_TO_PERFORM;

ldap/servers/slapd/slapi-plugin.h

@@ -1592,7 +1592,7 @@ typedef enum {
  * WARNING - return SUCCESS, and flag filter elements that are not in schema.
  * STRICT - return SUCCESS only if all elements are found - else return FAILURE.
  */
-Slapi_Filter_Result slapi_filter_schema_check(Slapi_Filter *f, Slapi_Filter_Policy fp);
+Slapi_Filter_Result slapi_filter_schema_check(Slapi_PBlock *pb, Slapi_Filter *f, Slapi_Filter_Policy fp);
 
 /**
  * Determines if the DN violates the Distinguished Name syntax rules.

ldap/servers/slapd/slapi-private.h

@@ -1456,6 +1456,7 @@ void slapi_pblock_set_pw_entry(Slapi_PBlock *pb, struct slapi_entry *entry);
 uint32_t slapi_pblock_get_operation_notes(Slapi_PBlock *pb);
 void slapi_pblock_set_operation_notes(Slapi_PBlock *pb, uint32_t opnotes);
 void slapi_pblock_set_flag_operation_notes(Slapi_PBlock *pb, uint32_t opflag);
+void slapi_pblock_set_result_text_if_empty(Slapi_PBlock *pb, char *text);
 
 #ifdef __cplusplus
 }

test/libslapd/schema/filter_validate.c

@@ -52,11 +52,13 @@ validate_filter(char *fstr, Slapi_Filter_Policy policy) {
     char fdup[256] = {0};
     strcpy(fdup, fstr);
     struct slapi_filter *f = slapi_str2filter(fdup);
+    Slapi_PBlock *pb = slapi_pblock_new();
     assert_true(f != NULL);
 
-    Slapi_Filter_Result r = slapi_filter_schema_check(f, policy);
+    Slapi_Filter_Result r = slapi_filter_schema_check(pb, f, policy);
     // Based on policy, we could assert if flags are set.
 
+    slapi_pblock_destroy(pb);
     slapi_filter_free(f, 1);
     return r;
 }
@@ -86,7 +88,9 @@ test_libslapd_schema_filter_validate_simple(void **state __attribute__((unused))
     /* Did they pass given the policy and expectations? */
 
     /* simple error cases */
-    assert_true(slapi_filter_schema_check(NULL, FILTER_POLICY_OFF) == FILTER_SCHEMA_FAILURE);
+    Slapi_PBlock *pb = slapi_pblock_new();
+    assert_true(slapi_filter_schema_check(pb, NULL, FILTER_POLICY_OFF) == FILTER_SCHEMA_FAILURE);
+    slapi_pblock_destroy(pb);
 
     /* policy off, always success no matter what */
     assert_true(validate_filter(invalid, FILTER_POLICY_OFF) == FILTER_SCHEMA_SUCCESS);