From a75805490d96a85786287f5d0522dd7671d6816e Mon Sep 17 00:00:00 2001 From: Andrew Bartlett Date: Thu, 3 Jan 2013 20:39:23 +1100 Subject: [PATCH 1/3] libcli/security: Ensure to fill in remaining_access for the initial case (bug #9554 - CVE-2013-0172) It is critically important that we initialise this element as otherwise all access is permitted. Andrew Bartlett Reviewed-by: Stefan Metzmacher --- libcli/security/object_tree.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/libcli/security/object_tree.c b/libcli/security/object_tree.c index 6809c8e..dcbd310 100644 --- a/libcli/security/object_tree.c +++ b/libcli/security/object_tree.c @@ -53,6 +53,7 @@ bool insert_in_object_tree(TALLOC_CTX *mem_ctx, return false; } (*root)->guid = *guid; + (*root)->remaining_access = init_access; *new_node = *root; return true; } -- 1.7.7 From d776fd807e0c9a62f428ce666ff812655f98bc47 Mon Sep 17 00:00:00 2001 From: Andrew Bartlett Date: Wed, 9 Jan 2013 16:59:18 +1100 Subject: [PATCH 2/3] dsdb-acl: Run sec_access_check_ds on each attribute proposed to modify (bug #9554 - CVE-2013-0172) This seems inefficient, but is needed for correctness. The alternative might be to have the sec_access_check_ds code confirm that *all* of the nodes in the object tree have been cleared to node->remaining_bits == 0. Otherwise, I fear that write access to one attribute will become write access to all attributes. Andrew Bartlett Signed-off-by: Stefan Metzmacher Reviewed-by: Stefan Metzmacher --- source4/dsdb/samdb/ldb_modules/acl.c | 55 ++++++++++++++++----------------- 1 files changed, 27 insertions(+), 28 deletions(-) diff --git a/source4/dsdb/samdb/ldb_modules/acl.c b/source4/dsdb/samdb/ldb_modules/acl.c index 9bf2612..3f09760 100644 --- a/source4/dsdb/samdb/ldb_modules/acl.c +++ b/source4/dsdb/samdb/ldb_modules/acl.c @@ -977,8 +977,6 @@ static int acl_modify(struct ldb_module *module, struct ldb_request *req) unsigned int i; const struct GUID *guid; uint32_t access_granted; - struct object_tree *root = NULL; - struct object_tree *new_node = NULL; NTSTATUS status; struct ldb_result *acl_res; struct security_descriptor *sd; @@ -1043,12 +1041,6 @@ static int acl_modify(struct ldb_module *module, struct ldb_request *req) "acl_modify: Error retrieving object class GUID."); } sid = samdb_result_dom_sid(req, acl_res->msgs[0], "objectSid"); - if (!insert_in_object_tree(tmp_ctx, guid, SEC_ADS_WRITE_PROP, - &root, &new_node)) { - talloc_free(tmp_ctx); - return ldb_error(ldb, LDB_ERR_OPERATIONS_ERROR, - "acl_modify: Error adding new node in object tree."); - } for (i=0; i < req->op.mod.message->num_elements; i++){ const struct dsdb_attribute *attr; attr = dsdb_attribute_by_lDAPDisplayName(schema, @@ -1129,6 +1121,8 @@ static int acl_modify(struct ldb_module *module, struct ldb_request *req) goto fail; } } else { + struct object_tree *root = NULL; + struct object_tree *new_node = NULL; /* This basic attribute existence check with the right errorcode * is needed since this module is the first one which requests @@ -1143,6 +1137,14 @@ static int acl_modify(struct ldb_module *module, struct ldb_request *req) ret = LDB_ERR_NO_SUCH_ATTRIBUTE; goto fail; } + + if (!insert_in_object_tree(tmp_ctx, guid, SEC_ADS_WRITE_PROP, + &root, &new_node)) { + talloc_free(tmp_ctx); + return ldb_error(ldb, LDB_ERR_OPERATIONS_ERROR, + "acl_modify: Error adding new node in object tree."); + } + if (!insert_in_object_tree(tmp_ctx, &attr->attributeSecurityGUID, SEC_ADS_WRITE_PROP, &new_node, &new_node)) { @@ -1159,27 +1161,24 @@ static int acl_modify(struct ldb_module *module, struct ldb_request *req) ret = LDB_ERR_OPERATIONS_ERROR; goto fail; } - } - } - - if (root->num_of_children > 0) { - status = sec_access_check_ds(sd, acl_user_token(module), - SEC_ADS_WRITE_PROP, - &access_granted, - root, - sid); - if (!NT_STATUS_IS_OK(status)) { - ldb_asprintf_errstring(ldb_module_get_ctx(module), - "Object %s has no write property access\n", - ldb_dn_get_linearized(req->op.mod.message->dn)); - dsdb_acl_debug(sd, - acl_user_token(module), - req->op.mod.message->dn, - true, - 10); - ret = LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS; - goto fail; + status = sec_access_check_ds(sd, acl_user_token(module), + SEC_ADS_WRITE_PROP, + &access_granted, + root, + sid); + if (!NT_STATUS_IS_OK(status)) { + ldb_asprintf_errstring(ldb_module_get_ctx(module), + "Object %s has no write property access\n", + ldb_dn_get_linearized(req->op.mod.message->dn)); + dsdb_acl_debug(sd, + acl_user_token(module), + req->op.mod.message->dn, + true, + 10); + ret = LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS; + goto fail; + } } } -- 1.7.7 From 8bafe0871526cd5d5e7fdbe123ab661379f64cb1 Mon Sep 17 00:00:00 2001 From: Andrew Bartlett Date: Thu, 10 Jan 2013 09:30:38 +1100 Subject: [PATCH 3/3] dsdb: Add test for modification of two attributes, one permitted, one denied (bug #9554 - CVE-2013-0172) Reviewed-by: Stefan Metzmacher --- source4/dsdb/tests/python/acl.py | 15 +++++++++++++++ 1 files changed, 15 insertions(+), 0 deletions(-) diff --git a/source4/dsdb/tests/python/acl.py b/source4/dsdb/tests/python/acl.py index 94bc504..ecda3c5 100755 --- a/source4/dsdb/tests/python/acl.py +++ b/source4/dsdb/tests/python/acl.py @@ -389,6 +389,21 @@ url: www.samba.org""" else: # This 'modify' operation should always throw ERR_INSUFFICIENT_ACCESS_RIGHTS self.fail() + # Modify on attribute you do not have rights for granted while also modifying something you do have rights for + ldif = """ +dn: CN=test_modify_group1,CN=Users,""" + self.base_dn + """ +changetype: modify +replace: url +url: www.samba.org +replace: displayName +displayName: test_changed""" + try: + self.ldb_user.modify_ldif(ldif) + except LdbError, (num, _): + self.assertEquals(num, ERR_INSUFFICIENT_ACCESS_RIGHTS) + else: + # This 'modify' operation should always throw ERR_INSUFFICIENT_ACCESS_RIGHTS + self.fail() # Second test object -- Organizational Unit print "Testing modify on OU object" self.ldb_admin.create_ou("OU=test_modify_ou1," + self.base_dn) -- 1.7.7