ITS#8007 Add maxentrysize config option

doc/man/man5/slapd-mdb.5

@@ -140,6 +140,11 @@ changing \fBindex\fP settings
 dynamically by LDAPModifying "cn=config" automatically causes rebuilding
 of the indices online in a background task.
 .TP
+.BI maxentrysize \ <bytes>
+Specify the maximum size of an entry in bytes. Attempts to store
+an entry larger than this size will be rejected with the error
+LDAP_ADMINLIMIT_EXCEEDED. The default is 0, which is unlimited.
+.TP
 .BI maxreaders \ <integer>
 Specify the maximum number of threads that may have concurrent read access
 to the database. Tools such as slapcat count as a single thread,

servers/slapd/back-mdb/add.c

@@ -335,8 +335,12 @@ mdb_add(Operation *op, SlapReply *rs )
 		Debug( LDAP_DEBUG_TRACE,
 			LDAP_XSTRING(mdb_add) ": id2entry_add failed\n",
 			0, 0, 0 );
-		rs->sr_err = LDAP_OTHER;
+		if ( rs->sr_err == LDAP_ADMINLIMIT_EXCEEDED ) {
-		rs->sr_text = "entry store failed";
+			rs->sr_text = "entry is too big";
+		} else {
+			rs->sr_err = LDAP_OTHER;
+			rs->sr_text = "entry store failed";
+		}
 		goto return_results;
 	}
 

servers/slapd/back-mdb/back-mdb.h

@@ -61,13 +61,13 @@ struct mdb_info {
 	MDB_env		*mi_dbenv;
 
 	/* DB_ENV parameters */
-	/* The DB_ENV can be tuned via DB_CONFIG */
 	char		*mi_dbenv_home;
 	uint32_t	mi_dbenv_flags;
 	int			mi_dbenv_mode;
 
 	size_t		mi_mapsize;
 	ID			mi_nextid;
+	size_t		mi_maxentrysize;
 
 	slap_mask_t	mi_defaultmask;
 	int			mi_nattrs;

servers/slapd/back-mdb/config.c

@@ -39,7 +39,8 @@ enum {
 	MDB_MAXREADERS,
 	MDB_MAXSIZE,
 	MDB_MODE,
-	MDB_SSTACK
+	MDB_SSTACK,
+	MDB_MAXENTSZ
 };
 
 static ConfigTable mdbcfg[] = {
@@ -66,6 +67,10 @@ static ConfigTable mdbcfg[] = {
 		"DESC 'Attribute index parameters' "
 		"EQUALITY caseIgnoreMatch "
 		"SYNTAX OMsDirectoryString )", NULL, NULL },
+	{ "maxentrysize", "size", 2, 2, 0, ARG_ULONG|ARG_MAGIC|MDB_MAXENTSZ,
+		mdb_cf_gen, "( OLcfgDbAt:12.3 NAME 'olcDbMaxEntrySize' "
+		"DESC 'Maximum size of an entry in bytes' "
+		"SYNTAX OMsInteger SINGLE-VALUE )", NULL, NULL },
 	{ "maxreaders", "num", 2, 2, 0, ARG_UINT|ARG_MAGIC|MDB_MAXREADERS,
 		mdb_cf_gen, "( OLcfgDbAt:12.1 NAME 'olcDbMaxReaders' "
 		"DESC 'Maximum number of threads that may access the DB concurrently' "
@@ -95,7 +100,7 @@ static ConfigOCs mdbocs[] = {
 		"MUST olcDbDirectory "
 		"MAY ( olcDbCheckpoint $ olcDbEnvFlags $ "
 		"olcDbNoSync $ olcDbIndex $ olcDbMaxReaders $ olcDbMaxsize $ "
-		"olcDbMode $ olcDbSearchStack ) )",
+		"olcDbMode $ olcDbSearchStack $ olcDbMaxEntrySize ) )",
 		 	Cft_Database, mdbcfg },
 	{ NULL, 0, NULL }
 };
@@ -329,6 +334,10 @@ mdb_cf_gen( ConfigArgs *c )
 			c->value_int = mdb->mi_search_stack_depth;
 			break;
 
+		case MDB_MAXENTSZ:
+			c->value_ulong = mdb->mi_maxentrysize;
+			break;
+
 		case MDB_MAXREADERS:
 			c->value_int = mdb->mi_readers;
 			break;
@@ -355,6 +364,10 @@ mdb_cf_gen( ConfigArgs *c )
 		case MDB_MAXSIZE:
 			break;
 
+		case MDB_MAXENTSZ:
+			mdb->mi_maxentrysize = 0;
+			break;
+
 		case MDB_CHKPT:
 			if ( mdb->mi_txn_cp_task ) {
 				struct re_s *re = mdb->mi_txn_cp_task;
@@ -651,6 +664,10 @@ mdb_cf_gen( ConfigArgs *c )
 		mdb->mi_search_stack_depth = c->value_int;
 		break;
 
+	case MDB_MAXENTSZ:
+		mdb->mi_maxentrysize = c->value_ulong;
+		break;
+
 	case MDB_MAXREADERS:
 		mdb->mi_readers = c->value_int;
 		if ( mdb->mi_flags & MDB_IS_OPEN ) {

servers/slapd/back-mdb/id2entry.c

@@ -63,6 +63,9 @@ static int mdb_id2entry_put(
 	if (e->e_id < mdb->mi_nextid)
 		flag &= ~MDB_APPEND;
 
+	if (mdb->mi_maxentrysize && ec.len > mdb->mi_maxentrysize)
+		return LDAP_ADMINLIMIT_EXCEEDED;
+
 again:
 	data.mv_size = ec.len;
 	if ( mc )

servers/slapd/back-mdb/modify.c

@@ -601,7 +601,12 @@ mdb_modify( Operation *op, SlapReply *rs )
 		Debug( LDAP_DEBUG_TRACE,
 			LDAP_XSTRING(mdb_modify) ": id2entry update failed " "(%d)\n",
 			rs->sr_err, 0, 0 );
-		rs->sr_text = "entry update failed";
+		if ( rs->sr_err == LDAP_ADMINLIMIT_EXCEEDED ) {
+			rs->sr_text = "entry too big";
+		} else {
+			rs->sr_err = LDAP_OTHER;
+			rs->sr_text = "entry update failed";
+		}
 		goto return_results;
 	}
 

servers/slapd/back-mdb/modrdn.c

@@ -487,8 +487,12 @@ mdb_modrdn( Operation	*op, SlapReply *rs )
 			"<=- " LDAP_XSTRING(mdb_modrdn)
 			": id2entry failed: %s (%d)\n",
 			mdb_strerror(rs->sr_err), rs->sr_err, 0 );
-		rs->sr_err = LDAP_OTHER;
+		if ( rs->sr_err == LDAP_ADMINLIMIT_EXCEEDED ) {
-		rs->sr_text = "entry update failed";
+			rs->sr_text = "entry too big";
+		} else {
+			rs->sr_err = LDAP_OTHER;
+			rs->sr_text = "entry update failed";
+		}
 		goto return_results;
 	}