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Extended Attributes for Security Modules
Hi, This patch against 2.5.67 implements changes to the LSM xattr-related hooks and adds xattr handlers for ext[23] to support the use of extended attributes by security modules for storing file security labels, as described in my April 8th RFC posting. I believe that I have responded to all questions and objections that were raised in response to the RFC, so I would ask that this patch be applied. The original RFC only included an xattr handler for ext3; this patch also includes an xattr handler for ext2 for consistency. If desired, I can split this into separate patches for ext2, ext3, and the changes to the LSM xattr-related hooks. fs/Kconfig | 24 +++++++++++++++++++++ fs/ext2/Makefile | 4 +++ fs/ext2/xattr.c | 21 ++++++++++++++++-- fs/ext2/xattr.h | 2 + fs/ext2/xattr_security.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++ fs/ext3/Makefile | 4 +++ fs/ext3/xattr.c | 21 ++++++++++++++++-- fs/ext3/xattr.h | 2 + fs/ext3/xattr_security.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++ fs/xattr.c | 7 +++--- include/linux/security.h | 15 +++++++++++++ security/dummy.c | 6 +++++ 12 files changed, 200 insertions(+), 9 deletions(-) Index: linux-2.5/fs/Kconfig diff -u linux-2.5/fs/Kconfig:1.1.1.3 linux-2.5/fs/Kconfig:1.5 --- linux-2.5/fs/Kconfig:1.1.1.3 Tue Mar 25 09:36:05 2003 +++ linux-2.5/fs/Kconfig Fri Apr 18 12:16:24 2003 @@ -73,6 +73,18 @@ If you don't know what Access Control Lists are, say N +config EXT2_FS_SECURITY + bool "Ext2 Security Labels" + depends on EXT2_FS_XATTR + help + Security labels support alternative access control models + implemented by security modules like SELinux. This option + enables an extended attribute handler for file security + labels in the ext2 filesystem. + + If you are not using a security module that requires using + extended attributes for file security labels, say N. + config EXT3_FS tristate "Ext3 journalling file system support" help @@ -130,6 +142,18 @@ Linux website <http://acl.bestbits.at/>. If you don't know what Access Control Lists are, say N + +config EXT3_FS_SECURITY + bool "Ext3 Security Labels" + depends on EXT3_FS_XATTR + help + Security labels support alternative access control models + implemented by security modules like SELinux. This option + enables an extended attribute handler for file security + labels in the ext3 filesystem. + + If you are not using a security module that requires using + extended attributes for file security labels, say N. config JBD # CONFIG_JBD could be its own option (even modular), but until there are Index: linux-2.5/fs/xattr.c diff -u linux-2.5/fs/xattr.c:1.1.1.1 linux-2.5/fs/xattr.c:1.4 --- linux-2.5/fs/xattr.c:1.1.1.1 Wed Mar 12 10:55:12 2003 +++ linux-2.5/fs/xattr.c Wed Mar 26 14:03:25 2003 @@ -79,15 +79,16 @@ error = -EOPNOTSUPP; if (d->d_inode->i_op && d->d_inode->i_op->setxattr) { + down(&d->d_inode->i_sem); error = security_inode_setxattr(d, kname, kvalue, size, flags); if (error) goto out; - down(&d->d_inode->i_sem); error = d->d_inode->i_op->setxattr(d, kname, kvalue, size, flags); + if (!error) + security_inode_post_setxattr(d, kname, kvalue, size, flags); +out: up(&d->d_inode->i_sem); } - -out: xattr_free(kvalue, size); return error; } Index: linux-2.5/fs/ext2/Makefile diff -u linux-2.5/fs/ext2/Makefile:1.1.1.1 linux-2.5/fs/ext2/Makefile:1.2 --- linux-2.5/fs/ext2/Makefile:1.1.1.1 Wed Mar 12 10:55:33 2003 +++ linux-2.5/fs/ext2/Makefile Fri Apr 18 12:16:34 2003 @@ -14,3 +14,7 @@ ifeq ($(CONFIG_EXT2_FS_POSIX_ACL),y) ext2-objs += acl.o endif + +ifeq ($(CONFIG_EXT2_FS_SECURITY),y) +ext2-objs += xattr_security.o +endif Index: linux-2.5/fs/ext2/xattr.c diff -u linux-2.5/fs/ext2/xattr.c:1.1.1.3 linux-2.5/fs/ext2/xattr.c:1.2 --- linux-2.5/fs/ext2/xattr.c:1.1.1.3 Tue Mar 25 09:37:24 2003 +++ linux-2.5/fs/ext2/xattr.c Fri Apr 18 12:16:34 2003 @@ -1101,22 +1101,33 @@ &ext2_xattr_trusted_handler); if (err) goto out; +#ifdef CONFIG_EXT2_FS_SECURITY + err = ext2_xattr_register(EXT2_XATTR_INDEX_SECURITY, + &ext2_xattr_security_handler); + if (err) + goto out1; +#endif #ifdef CONFIG_EXT2_FS_POSIX_ACL err = init_ext2_acl(); if (err) - goto out1; + goto out2; #endif ext2_xattr_cache = mb_cache_create("ext2_xattr", NULL, sizeof(struct mb_cache_entry) + sizeof(struct mb_cache_entry_index), 1, 6); if (!ext2_xattr_cache) { err = -ENOMEM; - goto out2; + goto out3; } return 0; -out2: +out3: #ifdef CONFIG_EXT2_FS_POSIX_ACL exit_ext2_acl(); +out2: +#endif +#ifdef CONFIG_EXT2_FS_SECURITY + ext2_xattr_unregister(EXT2_XATTR_INDEX_SECURITY, + &ext2_xattr_security_handler); out1: #endif ext2_xattr_unregister(EXT2_XATTR_INDEX_TRUSTED, @@ -1133,6 +1144,10 @@ mb_cache_destroy(ext2_xattr_cache); #ifdef CONFIG_EXT2_FS_POSIX_ACL exit_ext2_acl(); +#endif +#ifdef CONFIG_EXT2_FS_SECURITY + ext2_xattr_unregister(EXT2_XATTR_INDEX_SECURITY, + &ext2_xattr_security_handler); #endif ext2_xattr_unregister(EXT2_XATTR_INDEX_TRUSTED, &ext2_xattr_trusted_handler); Index: linux-2.5/fs/ext2/xattr.h diff -u linux-2.5/fs/ext2/xattr.h:1.1.1.1 linux-2.5/fs/ext2/xattr.h:1.2 --- linux-2.5/fs/ext2/xattr.h:1.1.1.1 Wed Mar 12 10:55:33 2003 +++ linux-2.5/fs/ext2/xattr.h Fri Apr 18 12:16:34 2003 @@ -22,6 +22,7 @@ #define EXT2_XATTR_INDEX_POSIX_ACL_ACCESS 2 #define EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT 3 #define EXT2_XATTR_INDEX_TRUSTED 4 +#define EXT2_XATTR_INDEX_SECURITY 5 struct ext2_xattr_header { __u32 h_magic; /* magic number for identification */ @@ -134,4 +135,5 @@ extern struct ext2_xattr_handler ext2_xattr_user_handler; extern struct ext2_xattr_handler ext2_xattr_trusted_handler; +extern struct ext2_xattr_handler ext2_xattr_security_handler; Index: linux-2.5/fs/ext2/xattr_security.c diff -u /dev/null linux-2.5/fs/ext2/xattr_security.c:1.1 --- /dev/null Fri Apr 18 12:31:13 2003 +++ linux-2.5/fs/ext2/xattr_security.c Fri Apr 18 12:16:34 2003 @@ -0,0 +1,51 @@ +/* + * linux/fs/ext2/xattr_security.c + * Handler for storing security labels as extended attributes. + */ + +#include <linux/module.h> +#include <linux/string.h> +#include <linux/fs.h> +#include <linux/smp_lock.h> +#include <linux/ext2_fs.h> +#include "xattr.h" + +#define XATTR_NAME_SECURITY "system.security" + +static size_t +ext2_xattr_security_list(char *list, struct inode *inode, + const char *name, int name_len) +{ + const int size = sizeof(XATTR_NAME_SECURITY); + + if (list) + memcpy(list, XATTR_NAME_SECURITY, size); + return size; +} + +static int +ext2_xattr_security_get(struct inode *inode, const char *name, + void *buffer, size_t size) +{ + if (strcmp(name, "") != 0) + return -EINVAL; + return ext2_xattr_get(inode, EXT2_XATTR_INDEX_SECURITY, name, + buffer, size); +} + +static int +ext2_xattr_security_set(struct inode *inode, const char *name, + const void *value, size_t size, int flags) +{ + if (strcmp(name, "") != 0) + return -EINVAL; + return ext2_xattr_set(inode, EXT2_XATTR_INDEX_SECURITY, name, + value, size, flags); +} + +struct ext2_xattr_handler ext2_xattr_security_handler = { + .prefix = XATTR_NAME_SECURITY, + .list = ext2_xattr_security_list, + .get = ext2_xattr_security_get, + .set = ext2_xattr_security_set, +}; Index: linux-2.5/fs/ext3/Makefile diff -u linux-2.5/fs/ext3/Makefile:1.1.1.1 linux-2.5/fs/ext3/Makefile:1.2 --- linux-2.5/fs/ext3/Makefile:1.1.1.1 Wed Mar 12 10:55:31 2003 +++ linux-2.5/fs/ext3/Makefile Wed Mar 26 14:03:26 2003 @@ -14,3 +14,7 @@ ifeq ($(CONFIG_EXT3_FS_POSIX_ACL),y) ext3-objs += acl.o endif + +ifeq ($(CONFIG_EXT3_FS_SECURITY),y) +ext3-objs += xattr_security.o +endif Index: linux-2.5/fs/ext3/xattr.c diff -u linux-2.5/fs/ext3/xattr.c:1.1.1.3 linux-2.5/fs/ext3/xattr.c:1.2 --- linux-2.5/fs/ext3/xattr.c:1.1.1.3 Tue Mar 25 09:37:19 2003 +++ linux-2.5/fs/ext3/xattr.c Wed Mar 26 14:03:26 2003 @@ -1141,22 +1141,33 @@ &ext3_xattr_trusted_handler); if (err) goto out; +#ifdef CONFIG_EXT3_FS_SECURITY + err = ext3_xattr_register(EXT3_XATTR_INDEX_SECURITY, + &ext3_xattr_security_handler); + if (err) + goto out1; +#endif #ifdef CONFIG_EXT3_FS_POSIX_ACL err = init_ext3_acl(); if (err) - goto out1; + goto out2; #endif ext3_xattr_cache = mb_cache_create("ext3_xattr", NULL, sizeof(struct mb_cache_entry) + sizeof(struct mb_cache_entry_index), 1, 6); if (!ext3_xattr_cache) { err = -ENOMEM; - goto out2; + goto out3; } return 0; -out2: +out3: #ifdef CONFIG_EXT3_FS_POSIX_ACL exit_ext3_acl(); +out2: +#endif +#ifdef CONFIG_EXT3_FS_SECURITY + ext3_xattr_unregister(EXT3_XATTR_INDEX_SECURITY, + &ext3_xattr_security_handler); out1: #endif ext3_xattr_unregister(EXT3_XATTR_INDEX_TRUSTED, @@ -1175,6 +1186,10 @@ ext3_xattr_cache = NULL; #ifdef CONFIG_EXT3_FS_POSIX_ACL exit_ext3_acl(); +#endif +#ifdef CONFIG_EXT3_FS_SECURITY + ext3_xattr_unregister(EXT3_XATTR_INDEX_SECURITY, + &ext3_xattr_security_handler); #endif ext3_xattr_unregister(EXT3_XATTR_INDEX_TRUSTED, &ext3_xattr_trusted_handler); Index: linux-2.5/fs/ext3/xattr.h diff -u linux-2.5/fs/ext3/xattr.h:1.1.1.1 linux-2.5/fs/ext3/xattr.h:1.2 --- linux-2.5/fs/ext3/xattr.h:1.1.1.1 Wed Mar 12 10:55:32 2003 +++ linux-2.5/fs/ext3/xattr.h Wed Mar 26 14:03:26 2003 @@ -21,6 +21,7 @@ #define EXT3_XATTR_INDEX_POSIX_ACL_ACCESS 2 #define EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT 3 #define EXT3_XATTR_INDEX_TRUSTED 4 +#define EXT3_XATTR_INDEX_SECURITY 5 struct ext3_xattr_header { __u32 h_magic; /* magic number for identification */ @@ -141,3 +142,4 @@ extern struct ext3_xattr_handler ext3_xattr_user_handler; extern struct ext3_xattr_handler ext3_xattr_trusted_handler; +extern struct ext3_xattr_handler ext3_xattr_security_handler; Index: linux-2.5/fs/ext3/xattr_security.c diff -u /dev/null linux-2.5/fs/ext3/xattr_security.c:1.1 --- /dev/null Fri Apr 18 12:31:13 2003 +++ linux-2.5/fs/ext3/xattr_security.c Wed Mar 26 14:03:26 2003 @@ -0,0 +1,52 @@ +/* + * linux/fs/ext3/xattr_security.c + * Handler for storing security labels as extended attributes. + */ + +#include <linux/module.h> +#include <linux/string.h> +#include <linux/fs.h> +#include <linux/smp_lock.h> +#include <linux/ext3_jbd.h> +#include <linux/ext3_fs.h> +#include "xattr.h" + +#define XATTR_NAME_SECURITY "system.security" + +static size_t +ext3_xattr_security_list(char *list, struct inode *inode, + const char *name, int name_len) +{ + const int size = sizeof(XATTR_NAME_SECURITY); + + if (list) + memcpy(list, XATTR_NAME_SECURITY, size); + return size; +} + +static int +ext3_xattr_security_get(struct inode *inode, const char *name, + void *buffer, size_t size) +{ + if (strcmp(name, "") != 0) + return -EINVAL; + return ext3_xattr_get(inode, EXT3_XATTR_INDEX_SECURITY, name, + buffer, size); +} + +static int +ext3_xattr_security_set(struct inode *inode, const char *name, + const void *value, size_t size, int flags) +{ + if (strcmp(name, "") != 0) + return -EINVAL; + return ext3_xattr_set(inode, EXT3_XATTR_INDEX_SECURITY, name, + value, size, flags); +} + +struct ext3_xattr_handler ext3_xattr_security_handler = { + .prefix = XATTR_NAME_SECURITY, + .list = ext3_xattr_security_list, + .get = ext3_xattr_security_get, + .set = ext3_xattr_security_set, +}; Index: linux-2.5/include/linux/security.h diff -u linux-2.5/include/linux/security.h:1.1.1.2 linux-2.5/include/linux/security.h:1.16 --- linux-2.5/include/linux/security.h:1.1.1.2 Wed Mar 19 09:54:58 2003 +++ linux-2.5/include/linux/security.h Fri Apr 18 11:17:19 2003 @@ -361,6 +361,9 @@ * Check permission before setting the extended attributes * @value identified by @name for @dentry. * Return 0 if permission is granted. + * @inode_post_setxattr: + * Update inode security field after successful setxattr operation. + * @value identified by @name for @dentry. * @inode_getxattr: * Check permission before obtaining the extended attributes * identified by @name for @dentry. @@ -1036,6 +1039,8 @@ void (*inode_delete) (struct inode *inode); int (*inode_setxattr) (struct dentry *dentry, char *name, void *value, size_t size, int flags); + void (*inode_post_setxattr) (struct dentry *dentry, char *name, void *value, + size_t size, int flags); int (*inode_getxattr) (struct dentry *dentry, char *name); int (*inode_listxattr) (struct dentry *dentry); int (*inode_removexattr) (struct dentry *dentry, char *name); @@ -1464,6 +1472,12 @@ return security_ops->inode_setxattr (dentry, name, value, size, flags); } +static inline void security_inode_post_setxattr (struct dentry *dentry, char *name, + void *value, size_t size, int flags) +{ + security_ops->inode_post_setxattr (dentry, name, value, size, flags); +} + static inline int security_inode_getxattr (struct dentry *dentry, char *name) { return security_ops->inode_getxattr (dentry, name); @@ -2063,6 +2087,10 @@ return 0; } +static inline void security_inode_post_setxattr (struct dentry *dentry, char *name, + void *value, size_t size, int flags) +{ } + static inline int security_inode_getxattr (struct dentry *dentry, char *name) { return 0; Index: linux-2.5/security/dummy.c diff -u linux-2.5/security/dummy.c:1.1.1.2 linux-2.5/security/dummy.c:1.14 --- linux-2.5/security/dummy.c:1.1.1.2 Wed Mar 19 09:59:17 2003 +++ linux-2.5/security/dummy.c Fri Apr 18 11:17:20 2003 @@ -334,6 +334,11 @@ return 0; } +static void dummy_inode_post_setxattr (struct dentry *dentry, char *name, void *value, + size_t size, int flags) +{ +} + static int dummy_inode_getxattr (struct dentry *dentry, char *name) { return 0; @@ -803,6 +818,7 @@ set_to_dummy_if_null(ops, inode_getattr); set_to_dummy_if_null(ops, inode_delete); set_to_dummy_if_null(ops, inode_setxattr); + set_to_dummy_if_null(ops, inode_post_setxattr); set_to_dummy_if_null(ops, inode_getxattr); set_to_dummy_if_null(ops, inode_listxattr); set_to_dummy_if_null(ops, inode_removexattr); -- Stephen Smalley <sds@epoch.ncsc.mil> National Security Agency - 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/ |
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