Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965106AbWHWTFd (ORCPT ); Wed, 23 Aug 2006 15:05:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965105AbWHWTFd (ORCPT ); Wed, 23 Aug 2006 15:05:33 -0400 Received: from e2.ny.us.ibm.com ([32.97.182.142]:2199 "EHLO e2.ny.us.ibm.com") by vger.kernel.org with ESMTP id S965103AbWHWTFc (ORCPT ); Wed, 23 Aug 2006 15:05:32 -0400 Subject: [PATCH 2/7] Integrity Service API and dummy provider From: Kylene Jo Hall To: linux-kernel , LSM ML Cc: Dave Safford , Mimi Zohar , Serge Hallyn Content-Type: text/plain Date: Wed, 23 Aug 2006 12:05:32 -0700 Message-Id: <1156359932.6720.65.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.0.4 (2.0.4-7) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10556 Lines: 334 This patch provides a framework and dummy provider for an integrity service. The three integrity functions provided are: integrity_verify_metadata integrity_verity_data integrity_measure (Details on the calls and their exact arguments are in linux/integrity.h, included in the patch.) Normally these functions would be called by an LSM module during d_instantiate. The first function is used to retrieve a requested dentry's label (xattr, such as security.selinux, or security.slim.level), along with the result of integrity verification of the label. Based on the result of this call, the LSM module may also choose to use integrity_verify_data to request a verification of the file's data, and integrity_measure, to commit the file's measurement to some form of logging/attestation service, such as a TPM. The latter two functions are separate calls, so that the LSM module can optimize performance by using them only as needed. For example, if the integrity_verify_metadata call shows that the label is not trustworthy, it is probably not necessary to hash and measure the file, as the current LSM check will likely be denied anyway. Updated to use more standard error returning per comments. Signed-off-by: Mimi Zohar Signed-off-by: Kylene Hall --- include/linux/integrity.h | 113 +++++++++++++++++++++++++++++++++++ security/Kconfig | 8 ++ security/Makefile | 1 security/integrity.c | 45 +++++++++++++ security/integrity_dummy.c | 76 +++++++++++++++++++++++ security/integrity_dummy.h | 12 +++ 6 files changed, 255 insertions(+) --- linux-2.6.18-rc3/security/integrity.c 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.18-rc3-working/security/integrity.c 2006-08-01 12:19:20.000000000 -0500 @@ -0,0 +1,45 @@ +/* + * integrity.c + * + * register integrity subsystem + * + * Copyright (C) 2005,2006 IBM Corporation + * Author: Mimi Zohar + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + */ + +#include +#include +#include +#include +#include +#include + +#include "integrity_dummy.h" + +struct integrity_operations *integrity_ops = &dummy_integrity_ops; + +int register_integrity(struct integrity_operations *ops) +{ + if (integrity_ops != &dummy_integrity_ops) + return -EAGAIN; + + integrity_ops = ops; + return 0; +} + +int unregister_integrity(struct integrity_operations *ops) +{ + if (ops != integrity_ops) + return -EINVAL; + + integrity_ops = &dummy_integrity_ops; + return 0; +} + +EXPORT_SYMBOL_GPL(register_integrity); +EXPORT_SYMBOL_GPL(unregister_integrity); +EXPORT_SYMBOL_GPL(integrity_ops); --- linux-2.6.18-rc3/security/integrity_dummy.c 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.18-rc3-working/security/integrity_dummy.c 2006-08-04 15:30:41.000000000 -0500 @@ -0,0 +1,76 @@ +/* + * integrity_dummy.c + * + * Instantiate integrity subsystem + * + * Copyright (C) 2005,2006 IBM Corporation + * Author: Mimi Zohar + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + */ + +#include +#include +#include +#include +#include + +/* + * Return the extended attribute + */ +static int dummy_verify_metadata(struct dentry *dentry, char *xattr_name, + char **xattr_value, int *xattr_value_len, + int *status) +{ + char *value; + int size; + int error; + + if (!xattr_value || !xattr_value_len || !status) + return -EINVAL; + + if (!dentry || !dentry->d_inode || !dentry->d_inode->i_op + || !dentry->d_inode->i_op->getxattr) { + return -EOPNOTSUPP; + } + + size = dentry->d_inode->i_op->getxattr(dentry, xattr_name, NULL, 0); + if (size < 0) { + if (size == -ENODATA) + *status = INTEGRITY_NOLABEL; + return size; + } + + value = kzalloc(size + 1, GFP_KERNEL); + if (!value) + return -ENOMEM; + + error = dentry->d_inode->i_op->getxattr(dentry, xattr_name, + value, size); + *xattr_value_len = size; + *xattr_value = value; + *status = INTEGRITY_PASS; + return error; +} + +static int dummy_verify_data(struct dentry *dentry, int *status) +{ + if (status) + *status = INTEGRITY_PASS; + return 0; +} + +static void dummy_measure(struct dentry *dentry, + const unsigned char *filename, int mask) +{ + return; +} + +struct integrity_operations dummy_integrity_ops = { + .verify_metadata = dummy_verify_metadata, + .verify_data = dummy_verify_data, + .measure = dummy_measure +}; + --- linux-2.6.18-rc3/security/integrity_dummy.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.18-rc3-working/security/integrity_dummy.h 2006-08-01 12:19:20.000000000 -0500 @@ -0,0 +1,12 @@ +/* + * integrity_dummy.h + * + * Copyright (C) 2005,2006 IBM Corporation + * Author: Mimi Zohar + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + */ + +extern struct integrity_operations dummy_integrity_ops; --- linux-2.6.18/include/linux/integrity.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.18-rc3-working/include/linux/integrity.h 2006-08-22 16:40:45.000000000 -0500 @@ -0,0 +1,113 @@ +/* + * integrity.h + * + * Copyright (C) 2005,2006 IBM Corporation + * Author: Mimi Zohar + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + */ + +#ifndef _LINUX_INTEGRITY_H +#define _LINUX_INTEGRITY_H + +#include + +/* + * struct integrity_operations - main integrity structure + * + * @verify_data: + * Verify the integrity of a dentry. + * @dentry contains the dentry structure to be verified. + * @status contains INTEGRITY_PASS, INTEGRITY_FAIL, or + * INTEGRITY_NOLABEL + * Return 0 on success or errno values + * + * @verify_metadata: + * Verify the integrity of a dentry's metadata; return the value + * of the requested xattr_name and the verification result of the + * dentry's metadata. + * @dentry contains the dentry structure of the metadata to be verified. + * @xattr_name, if not null, contains the name of the xattr + * being requested. + * @xattr_value, if not null, is a pointer for the xattr value. + * @xattr_val_len will be set to the length of the xattr value. + * @status contains INTEGRITY_PASS, INTEGRITY_FAIL, or + * INTEGRITY_NOLABEL + * Return 0 on success or errno values + * + * @measure: + * Update an aggregate integrity value with the inode's measurement. + * The aggregate integrity value is maintained in secure storage such + * as in a TPM PCR. + * @dentry contains the dentry structure of the inode to be measured. + * @filename either contains the full pathname/short file name. + * @mask contains the filename permission status(i.e. read, write, append). + * + */ + +#define PASS_STR "INTEGRITY_PASS" +#define FAIL_STR "INTEGRITY_FAIL" +#define NOLABEL_STR "INTEGRITY_NOLABEL" + +struct integrity_operations { + int (*verify_metadata) (struct dentry *dentry, char *xattr_name, + char **xattr_value, int *xattr_val_len, int *status); + int (*verify_data) (struct dentry *dentry, int *status); + void (*measure) (struct dentry *dentry, + const unsigned char *filename, int mask); +}; +extern int register_integrity(struct integrity_operations *ops); +extern int unregister_integrity(struct integrity_operations *ops); + +/* global variables */ +extern struct integrity_operations *integrity_ops; +enum integrity_verify_status { + INTEGRITY_PASS = 0, INTEGRITY_FAIL = -1, INTEGRITY_NOLABEL = -2 +}; + +/* inline stuff */ +#ifdef CONFIG_INTEGRITY +static inline int integrity_verify_metadata(struct dentry *dentry, + char *xattr_name, char **xattr_value, + int *xattr_val_len, int *status) +{ + return integrity_ops->verify_metadata(dentry, xattr_name, + xattr_value, xattr_val_len, status); +} + +static inline int integrity_verify_data(struct dentry *dentry, + int *status) +{ + return integrity_ops->verify_data(dentry, status); +} + +static inline void integrity_measure(struct dentry *dentry, + const unsigned char *filename, int mask) +{ + return integrity_ops->measure(dentry, filename, mask); +} +#else +static inline int integrity_verify_metadata(struct dentry *dentry, + char *xattr_name, char **xattr_value, + int *xattr_val_len, int *status) +{ + status = INTEGRITY_PASS; + return 0; +} + +static inline int integrity_verify_data(struct dentry *dentry, + int *status) +{ + status = INTEGRITY_PASS; + return 0; +} + +static inline void integrity_measure(struct dentry *dentry, + const unsigned char *filename, int mask) +{ + return 0; +} +#endif +#endif --- linux-2.6.18-rc3/security/Makefile 2006-08-09 12:19:17.000000000 -0500 +++ linux-2.6.18-rc3-working/security/Makefile 2006-08-22 16:18:31.000000000 -0500 @@ -13,6 +13,7 @@ endif # Object file lists obj-$(CONFIG_SECURITY) += security.o dummy.o inode.o +obj-$(CONFIG_INTEGRITY) += integrity.o integrity_dummy.o # Must precede capability.o in order to stack properly. obj-$(CONFIG_SECURITY_SELINUX) += selinux/built-in.o obj-$(CONFIG_SECURITY_CAPABILITIES) += commoncap.o capability.o --- linux-2.6.18-rc3/security/Kconfig 2006-08-09 12:19:17.000000000 -0500 +++ linux-2.6.18-rc3-working/security/Kconfig 2006-08-22 16:21:18.000000000 -0500 @@ -39,6 +39,14 @@ config KEYS_DEBUG_PROC_KEYS If you are unsure as to whether this is required, answer N. +config INTEGRITY + bool "Enable different integrity models" + help + This allows you to choose different integrity modules to be + configured into your kernel. + + If you are unsure how to answer this question, answer N. + config SECURITY bool "Enable different security models" depends on SYSFS - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/