s4:ldb: add infrastructure for extended dn handlers

This introduces a new set of pluggable syntax, for use on the
extended DN, and uses them when parsing the DN.

If the DN appears to be in the extended form, we no longer return the
full DN 'as is', but only return the normal part from
ldb_dn_get_linearized().

When validating/parsing the DN we validate not only the format of the
DN, but also the contents of the GUID or SID (to ensure they are
plausable).

We also have functions to set and get the extended components on the DN.

For now, extended_dn_get_linearized() returns a newly constructed and
allocated string each time.

Signed-off-by: Stefan Metzmacher <metze@samba.org>

2 files changed, 82 insertions, 2 deletions

diff --git a/source4/lib/ldb/include/ldb.h b/source4/lib/ldb/include/ldb.h
index 9bc5c183d8..cd7eb06b4d 100644
--- a/source4/lib/ldb/include/ldb.h
+++ b/source4/lib/ldb/include/ldb.h
@@ -350,6 +350,16 @@ struct ldb_schema_attribute {
 const struct ldb_schema_attribute *ldb_schema_attribute_by_name(struct ldb_context *ldb,
 								const char *name);
 
+struct ldb_dn_extended_syntax {
+	const char *name;
+	ldb_attr_handler_t read_fn;
+	ldb_attr_handler_t write_clear_fn;
+	ldb_attr_handler_t write_hex_fn;
+};
+
+const struct ldb_dn_extended_syntax *ldb_dn_extended_syntax_by_name(struct ldb_context *ldb,
+								    const char *name);
+
 /**
    The attribute is not returned by default
 */
@@ -1421,15 +1431,82 @@ int ldb_base64_decode(char *s);
 
 /* The following definitions come from lib/ldb/common/ldb_dn.c  */
 
+/**
+  Get the linear form of a DN (without any extended components)
+  
+  \param dn The DN to linearize
+*/
+
+const char *ldb_dn_get_linearized(struct ldb_dn *dn);
+
+/**
+  Allocate a copy of the linear form of a DN (without any extended components) onto the supplied memory context 
+  
+  \param dn The DN to linearize
+  \param mem_ctx TALLOC context to return result on
+*/
+
+char *ldb_dn_alloc_linearized(TALLOC_CTX *mem_ctx, struct ldb_dn *dn);
+
+/**
+  Get the linear form of a DN (with any extended components)
+  
+  \param mem_ctx TALLOC context to return result on
+  \param dn The DN to linearize
+  \param mode Style of extended DN to return (0 is HEX representation of binary form, 1 is a string form)
+*/
+char *ldb_dn_get_extended_linearized(void *mem_ctx, struct ldb_dn *dn, int mode);
+const struct ldb_val *ldb_dn_get_extended_component(struct ldb_dn *dn, const char *name);
+int ldb_dn_set_extended_component(struct ldb_dn *dn, const char *name, const struct ldb_val *val);
+
+void ldb_dn_remove_extended_components(struct ldb_dn *dn);
+bool ldb_dn_has_extended(struct ldb_dn *dn);
+
+int ldb_dn_extended_add_syntax(struct ldb_context *ldb, 
+			       unsigned flags,
+			       const struct ldb_dn_extended_syntax *syntax);
+
+/** 
+  Allocate a new DN from a string
+
+  \param mem_ctx TALLOC context to return resulting ldb_dn structure on
+  \param dn The new DN 
+
+  \note The DN will not be parsed at this time.  Use ldb_dn_validate to tell if the DN is syntacticly correct
+*/
+
 struct ldb_dn *ldb_dn_new(TALLOC_CTX *mem_ctx, struct ldb_context *ldb, const char *dn);
+/** 
+  Allocate a new DN from a printf style format string and arguments
+
+  \param mem_ctx TALLOC context to return resulting ldb_dn structure on
+  \param new_fms The new DN as a format string (plus arguments)
+
+  \note The DN will not be parsed at this time.  Use ldb_dn_validate to tell if the DN is syntacticly correct
+*/
+
 struct ldb_dn *ldb_dn_new_fmt(TALLOC_CTX *mem_ctx, struct ldb_context *ldb, const char *new_fmt, ...) PRINTF_ATTRIBUTE(3,4);
+/** 
+  Allocate a new DN from a struct ldb_val (useful to avoid buffer overrun)
+
+  \param mem_ctx TALLOC context to return resulting ldb_dn structure on
+  \param dn The new DN 
+
+  \note The DN will not be parsed at this time.  Use ldb_dn_validate to tell if the DN is syntacticly correct
+*/
+
 struct ldb_dn *ldb_dn_from_ldb_val(void *mem_ctx, struct ldb_context *ldb, const struct ldb_val *strdn);
+
+/**
+  Determine if this DN is syntactically valid 
+
+  \param dn The DN to validate
+*/
+
 bool ldb_dn_validate(struct ldb_dn *dn);
 
 char *ldb_dn_escape_value(TALLOC_CTX *mem_ctx, struct ldb_val value);
-const char *ldb_dn_get_linearized(struct ldb_dn *dn);
 const char *ldb_dn_get_casefold(struct ldb_dn *dn);
-char *ldb_dn_alloc_linearized(TALLOC_CTX *mem_ctx, struct ldb_dn *dn);
 char *ldb_dn_alloc_casefold(TALLOC_CTX *mem_ctx, struct ldb_dn *dn);
 
 int ldb_dn_compare_base(struct ldb_dn *base, struct ldb_dn *dn);
diff --git a/source4/lib/ldb/include/ldb_private.h b/source4/lib/ldb/include/ldb_private.h
index 90c4980017..d1d3587eb7 100644
--- a/source4/lib/ldb/include/ldb_private.h
+++ b/source4/lib/ldb/include/ldb_private.h
@@ -84,6 +84,9 @@ struct ldb_schema {
 	/* attribute handling table */
 	unsigned num_attributes;
 	struct ldb_schema_attribute *attributes;
+
+	unsigned num_dn_extended_syntax;
+	struct ldb_dn_extended_syntax *dn_extended_syntax;
 };
 
 /*