Initial implementation of security descriptor creation in DS

TODO's:
ACE sorting and clarifying the inheritance of object specific ace's.

1 files changed, 348 insertions, 4 deletions

diff --git a/source4/libcli/security/create_descriptor.c b/source4/libcli/security/create_descriptor.c
index 6a928273b7..1054479f28 100644
--- a/source4/libcli/security/create_descriptor.c
+++ b/source4/libcli/security/create_descriptor.c
@@ -29,6 +29,18 @@
 #include "includes.h"
 #include "libcli/security/security.h"
 
+/* Todos:
+ * build the security token dacl as follows:
+ * SYSTEM: GA, OWNER: GA, LOGIN_SID:GW|GE
+ * Need session id information for the login SID. Probably
+ * the best place for this is during token creation
+ *
+ * Implement SD Invariants
+ * ACE sorting rules
+ * LDAP_SERVER_SD_FLAGS_OID control
+ * ADTS 7.1.3.3 needs to be clarified
+ */
+
 /* the mapping function for generic rights for DS.(GA,GR,GW,GX)
  * The mapping function is passed as an argument to the
  * descriptor calculating routine and depends on the security
@@ -63,6 +75,328 @@ uint32_t map_generic_rights_ds(uint32_t access_mask)
 	return access_mask;
 }
 
+/* Not sure what this has to be,
+* and it does not seem to have any influence */
+static bool object_in_list(struct GUID *object_list, struct GUID *object)
+{
+	return true;
+}
+
+
+static bool contains_inheritable_aces(struct security_acl *acl)
+{
+        int i;
+	if (!acl)
+		return false;
+
+	for (i=0; i < acl->num_aces; i++) {
+		struct security_ace *ace = &acl->aces[i];
+		if ((ace->flags & SEC_ACE_FLAG_CONTAINER_INHERIT) ||
+		    (ace->flags & SEC_ACE_FLAG_OBJECT_INHERIT))
+			return true;
+	}
+
+	return false;
+}
+
+static struct security_acl *preprocess_creator_acl(TALLOC_CTX *mem, struct security_acl *acl)
+{
+	int i;
+	struct security_acl *new_acl = talloc_zero(mem, struct security_acl);
+
+	new_acl->revision = acl->revision;
+	for (i=0; i < acl->num_aces; i++) {
+		struct security_ace *ace = &acl->aces[i];
+		if (!(ace->flags & SEC_ACE_FLAG_INHERITED_ACE)){
+			new_acl->aces = talloc_realloc(new_acl, new_acl->aces, struct security_ace,
+					   new_acl->num_aces+1);
+			if (new_acl->aces == NULL) {
+				talloc_free(new_acl);
+				return NULL;
+			}
+			new_acl->aces[new_acl->num_aces] = *ace;
+			/*memcpy(&new_acl->aces[new_acl->num_aces], ace,
+			  sizeof(struct security_ace)); */
+			new_acl->num_aces++;
+		}
+	}
+	if (new_acl)
+		new_acl->revision = acl->revision;
+	/* Todo what to do if all were inherited and this is empty */
+	return new_acl;
+}
+
+/* This is not exactly as described in the docs. The original seemed to return
+ * only a list of the inherited or flagless ones... */
+
+static bool postprocess_acl(struct security_acl *acl,
+			    struct dom_sid *owner,
+			    struct dom_sid *group,
+			    uint32_t (*generic_map)(uint32_t access_mask))
+{
+	int i;
+	struct dom_sid *co, *cg;
+	TALLOC_CTX *tmp_ctx = talloc_new(acl);
+	if (!generic_map){
+		return false;
+	}
+	co = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_OWNER);
+	cg = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_GROUP);
+	for (i=0; i < acl->num_aces; i++){
+		struct security_ace *ace = &acl->aces[i];
+		if (!(ace->flags == 0 || ace->flags & SEC_ACE_FLAG_INHERITED_ACE))
+			continue;
+		if (ace->flags & SEC_ACE_FLAG_INHERIT_ONLY)
+			continue;
+		if (dom_sid_equal(&ace->trustee, co)){
+			ace->trustee = *owner;
+			/* perhaps this should be done somewhere else? */
+			ace->flags &= ~SEC_ACE_FLAG_CONTAINER_INHERIT;
+		}
+		if (dom_sid_equal(&ace->trustee, cg)){
+			ace->trustee = *group;
+			ace->flags &= ~SEC_ACE_FLAG_CONTAINER_INHERIT;
+		}
+		ace->access_mask = generic_map(ace->access_mask);
+	}
+
+	talloc_free(tmp_ctx);
+	return true;
+}
+
+static struct security_acl *calculate_inherited_from_parent(TALLOC_CTX *mem_ctx,
+						struct security_acl *acl,
+						bool is_container,
+						struct GUID *object_list)
+{
+	int i;
+	TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
+	struct security_acl *tmp_acl = talloc_zero(tmp_ctx, struct security_acl);
+	struct security_acl *inh_acl = talloc_zero(tmp_ctx, struct security_acl);
+	struct security_acl *new_acl;
+	struct dom_sid *co, *cg;
+	if (!tmp_acl || !inh_acl)
+		return NULL;
+
+	co = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_OWNER);
+	cg = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_GROUP);
+
+	for (i=0; i < acl->num_aces; i++){
+		struct security_ace *ace = &acl->aces[i];
+		if (ace->flags & SEC_ACE_FLAG_INHERIT_ONLY)
+			continue;
+
+		if ((ace->flags & SEC_ACE_FLAG_CONTAINER_INHERIT) ||
+		    (ace->flags & SEC_ACE_FLAG_OBJECT_INHERIT)){
+			tmp_acl->aces = talloc_realloc(tmp_acl, tmp_acl->aces, struct security_ace,
+						       tmp_acl->num_aces+1);
+			if (tmp_acl->aces == NULL) {
+				talloc_free(tmp_ctx);
+				return NULL;
+			}
+
+			tmp_acl->aces[tmp_acl->num_aces] = *ace;
+			tmp_acl->aces[tmp_acl->num_aces].flags |= SEC_ACE_FLAG_INHERITED_ACE;
+
+			if (is_container && (ace->flags & SEC_ACE_FLAG_OBJECT_INHERIT))
+			    tmp_acl->aces[tmp_acl->num_aces].flags |= SEC_ACE_FLAG_INHERIT_ONLY;
+
+			if (ace->type == SEC_ACE_TYPE_ACCESS_ALLOWED_OBJECT ||
+			    ace->type == SEC_ACE_TYPE_ACCESS_DENIED_OBJECT){
+				if (!object_in_list(object_list, &ace->object.object.type.type)){
+					tmp_acl->aces[tmp_acl->num_aces].flags |= SEC_ACE_FLAG_INHERIT_ONLY;
+				}
+
+			}
+			tmp_acl->num_aces++;
+		}
+	}
+
+	if (is_container){
+		for (i=0; i < acl->num_aces; i++){
+			struct security_ace *ace = &acl->aces[i];
+
+			if (ace->flags & SEC_ACE_FLAG_NO_PROPAGATE_INHERIT)
+				continue;
+			if (!dom_sid_equal(&ace->trustee, co) && !dom_sid_equal(&ace->trustee, cg))
+				continue;
+
+			if ((ace->flags & SEC_ACE_FLAG_CONTAINER_INHERIT) ||
+			    (ace->flags & SEC_ACE_FLAG_OBJECT_INHERIT)){
+				inh_acl->aces = talloc_realloc(inh_acl, inh_acl->aces, struct security_ace,
+							       inh_acl->num_aces+1);
+				if (inh_acl->aces == NULL){
+					talloc_free(tmp_ctx);
+					return NULL;
+				}
+				inh_acl->aces[inh_acl->num_aces] = *ace;
+				inh_acl->aces[inh_acl->num_aces].flags |= SEC_ACE_FLAG_INHERIT_ONLY;
+				inh_acl->aces[inh_acl->num_aces].flags |= SEC_ACE_FLAG_INHERITED_ACE;
+				inh_acl->num_aces++;
+			}
+		}
+	}
+	new_acl = security_acl_concatenate(mem_ctx,tmp_acl, inh_acl);
+	if (new_acl)
+		new_acl->revision = acl->revision;
+	talloc_free(tmp_ctx);
+	return new_acl;
+}
+
+/* In the docs this looks == calculate_inherited_from_parent. However,
+ * It shouldn't return the inherited, rather filter them out....
+ */
+static struct security_acl *calculate_inherited_from_creator(TALLOC_CTX *mem_ctx,
+						struct security_acl *acl,
+						bool is_container,
+						struct GUID *object_list)
+{
+	int i;
+	TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
+	struct security_acl *tmp_acl = talloc_zero(tmp_ctx, struct security_acl);
+/*	struct security_acl *inh_acl = talloc_zero(tmp_ctx, struct security_acl); */
+	struct security_acl *new_acl;
+	struct dom_sid *co, *cg;
+
+	if (!tmp_acl)
+		return NULL;
+
+	co = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_OWNER);
+	cg = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_GROUP);
+
+	for (i=0; i < acl->num_aces; i++){
+		struct security_ace *ace = &acl->aces[i];
+		if (ace->flags & SEC_ACE_FLAG_INHERITED_ACE)
+			continue;
+
+		tmp_acl->aces = talloc_realloc(tmp_acl, tmp_acl->aces, struct security_ace,
+					      tmp_acl->num_aces+1);
+		tmp_acl->aces[tmp_acl->num_aces] = *ace;
+		tmp_acl->aces[tmp_acl->num_aces].flags  = 0;
+		tmp_acl->num_aces++;
+
+		if (!dom_sid_equal(&ace->trustee, co) && !dom_sid_equal(&ace->trustee, cg))
+			continue;
+
+		tmp_acl->aces = talloc_realloc(tmp_acl, tmp_acl->aces, struct security_ace,
+					       tmp_acl->num_aces+1);
+		tmp_acl->aces[tmp_acl->num_aces] = *ace;
+		tmp_acl->aces[tmp_acl->num_aces].flags |= SEC_ACE_FLAG_INHERIT_ONLY;
+		tmp_acl->num_aces++;
+	}
+	new_acl = security_acl_dup(mem_ctx,tmp_acl);
+
+	talloc_free(tmp_ctx);
+	return new_acl;
+}
+
+static bool compute_acl(int acl_type,
+			struct security_descriptor *parent_sd,
+			struct security_descriptor *creator_sd,
+			bool is_container,
+			uint32_t inherit_flags,
+			struct GUID *object_list,
+			uint32_t (*generic_map)(uint32_t access_mask),
+			struct security_token *token,
+			struct security_descriptor *new_sd) /* INOUT argument */
+{
+	struct security_acl *p_acl = NULL, *c_acl = NULL, **new_acl;
+	if (acl_type == SEC_DESC_DACL_PRESENT){
+		if (parent_sd)
+			p_acl = parent_sd->dacl;
+		if (creator_sd)
+			c_acl = creator_sd->dacl;
+		new_acl = &new_sd->dacl;
+	}
+	else{
+		if (parent_sd)
+			p_acl = parent_sd->sacl;
+		if (creator_sd)
+			c_acl = creator_sd->sacl;
+		new_acl = &new_sd->sacl;
+	}
+	if (contains_inheritable_aces(p_acl)){
+		if (!c_acl || (c_acl && inherit_flags & SEC_DEFAULT_DESCRIPTOR)){
+			*new_acl = calculate_inherited_from_parent(new_sd,
+						       p_acl,
+						       is_container,
+						       object_list);
+			if (*new_acl == NULL)
+				goto final;
+			if (!postprocess_acl(*new_acl, new_sd->owner_sid,
+					     new_sd->group_sid, generic_map))
+				return false;
+			else
+				goto final;
+		}
+		if (c_acl && !(inherit_flags & SEC_DEFAULT_DESCRIPTOR)){
+			struct security_acl *pr_acl, *tmp_acl, *tpr_acl;
+			tpr_acl = preprocess_creator_acl(new_sd, c_acl);
+			tmp_acl = calculate_inherited_from_creator(new_sd,
+						      tpr_acl,
+						      is_container,
+						      object_list);
+			/* Todo some refactoring here! */
+			if (acl_type == SEC_DESC_DACL_PRESENT &&
+			    !(creator_sd->type & SECINFO_PROTECTED_DACL) &&
+			    (inherit_flags & SEC_DACL_AUTO_INHERIT)){
+				pr_acl = calculate_inherited_from_parent(new_sd,
+							     p_acl,
+							     is_container,
+							     object_list);
+
+				*new_acl = security_acl_concatenate(new_sd, tmp_acl, pr_acl);
+				new_sd->type |= SEC_DESC_DACL_AUTO_INHERITED;
+			}
+			else if (acl_type == SEC_DESC_SACL_PRESENT &&
+			    !(creator_sd->type & SECINFO_PROTECTED_SACL) &&
+			    (inherit_flags & SEC_SACL_AUTO_INHERIT)){
+				pr_acl = calculate_inherited_from_parent(new_sd,
+							     p_acl,
+							     is_container,
+							     object_list);
+
+				*new_acl = security_acl_concatenate(new_sd, tmp_acl, pr_acl);
+				new_sd->type |= SEC_DESC_SACL_AUTO_INHERITED;
+			}
+		}
+		if (*new_acl == NULL)
+			goto final;
+		if (!postprocess_acl(*new_acl, new_sd->owner_sid,
+				     new_sd->group_sid,generic_map))
+			return false;
+		else
+			goto final;
+	}
+	else{
+		if (!c_acl){
+			if (acl_type == SEC_DESC_DACL_PRESENT && token->default_dacl)
+				*new_acl = security_acl_dup(new_sd, token->default_dacl);
+		}
+		else{
+			*new_acl = preprocess_creator_acl(new_sd,c_acl);
+			if (*new_acl == NULL)
+				goto final;
+			if (!postprocess_acl(*new_acl, new_sd->owner_sid,
+					     new_sd->group_sid,generic_map))
+				return false;
+			else
+				goto final;
+		}
+	}
+final:
+	if (acl_type == SEC_DESC_DACL_PRESENT && new_sd->dacl)
+		new_sd->type |= SEC_DESC_DACL_PRESENT;
+
+	if (acl_type == SEC_DESC_SACL_PRESENT && new_sd->sacl)
+		new_sd->type |= SEC_DESC_SACL_PRESENT;
+	/* This is a hack to handle the fact that
+	 * apprantly any AI flag provided by the user is preserved */
+	if (creator_sd)
+		new_sd->type |= creator_sd->type;
+	return true;
+}
+
 struct security_descriptor *create_security_descriptor(TALLOC_CTX *mem_ctx,
 						       struct security_descriptor *parent_sd,
 						       struct security_descriptor *creator_sd,
@@ -108,10 +442,20 @@ struct security_descriptor *create_security_descriptor(TALLOC_CTX *mem_ctx,
 		talloc_free(new_sd);
 		return NULL;
 	}
-	/* Todo remove */
-	if (creator_sd && creator_sd->type & SEC_DESC_DACL_PRESENT){
-		new_sd->dacl = security_acl_dup(new_sd, creator_sd->dacl);
-		new_sd->type |= SEC_DESC_DACL_PRESENT;
+
+	if (!compute_acl(SEC_DESC_DACL_PRESENT, parent_sd, creator_sd,
+			 is_container, inherit_flags, object_list,
+			 generic_map,token,new_sd)){
+		talloc_free(new_sd);
+		return NULL;
 	}
+
+	if (!compute_acl(SEC_DESC_SACL_PRESENT, parent_sd, creator_sd,
+			 is_container, inherit_flags, object_list,
+			 generic_map, token,new_sd)){
+		talloc_free(new_sd);
+		return NULL;
+	}
+
 	return new_sd;
 }