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Commit aa98d7cf authored by KaiGai Kohei's avatar KaiGai Kohei
Browse files

[JFFS2][XATTR] XATTR support on JFFS2 (version. 5) 



This attached patches provide xattr support including POSIX-ACL and
SELinux support on JFFS2 (version.5).

There are some significant differences from previous version posted
at last December.
The biggest change is addition of EBS(Erase Block Summary) support.
Currently, both kernel and usermode utility (sumtool) can recognize
xattr nodes which have JFFS2_NODETYPE_XATTR/_XREF nodetype.

In addition, some bugs are fixed.
- A potential race condition was fixed.
- Unexpected fail when updating a xattr by same name/value pair was fixed.
- A bug when removing xattr name/value pair was fixed.

The fundamental structures (such as using two new nodetypes and exclusion
mechanism by rwsem) are unchanged. But most of implementation were reviewed
and updated if necessary.
Espacially, we had to change several internal implementations related to
load_xattr_datum() to avoid a potential race condition.

[1/2] xattr_on_jffs2.kernel.version-5.patch
[2/2] xattr_on_jffs2.utils.version-5.patch

Signed-off-by: default avatarKaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent 4992a9e8

fs/Kconfig

+38 −0
Original line number Diff line number Diff line
@@ -1075,6 +1075,44 @@ config JFFS2_FS_DEBUG 
	  If reporting bugs, please try to have available a full dump of the

	  messages at debug level 1 while the misbehaviour was occurring.



config JFFS2_FS_XATTR

	bool "JFFS2 XATTR support"

	depends on JFFS2_FS

	default n

	help

	  Extended attributes are name:value pairs associated with inodes by

	  the kernel or by users (see the attr(5) manual page, or visit

	  <http://acl.bestbits.at/> for details).

	  

	  If unsure, say N.



config JFFS2_FS_POSIX_ACL

	bool "JFFS2 POSIX Access Control Lists"

	depends on JFFS2_FS_XATTR

	default y

	select FS_POSIX_ACL

	help

	  Posix Access Control Lists (ACLs) support permissions for users and

	  groups beyond the owner/group/world scheme.

	  

	  To learn more about Access Control Lists, visit the Posix ACLs for

	  Linux website <http://acl.bestbits.at/>.

	  

	  If you don't know what Access Control Lists are, say N



config JFFS2_FS_SECURITY

	bool "JFFS2 Security Labels"

	depends on JFFS2_FS_XATTR

	default y

	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 jffs2 filesystem.

	  

	  If you are not using a security module that requires using

	  extended attributes for file security labels, say N.



config JFFS2_FS_WRITEBUFFER

	bool "JFFS2 write-buffering support"

	depends on JFFS2_FS

fs/jffs2/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -12,6 +12,9 @@ jffs2-y += symlink.o build.o erase.o background.o fs.o writev.o 
jffs2-y	+= super.o debug.o



jffs2-$(CONFIG_JFFS2_FS_WRITEBUFFER)	+= wbuf.o

jffs2-$(CONFIG_JFFS2_FS_XATTR)		+= xattr.o xattr_trusted.o xattr_user.o

jffs2-$(CONFIG_JFFS2_FS_SECURITY)	+= security.o

jffs2-$(CONFIG_JFFS2_FS_POSIX_ACL)	+= acl.o

jffs2-$(CONFIG_JFFS2_RUBIN)	+= compr_rubin.o

jffs2-$(CONFIG_JFFS2_RTIME)	+= compr_rtime.o

jffs2-$(CONFIG_JFFS2_ZLIB)	+= compr_zlib.o

fs/jffs2/acl.c

0 → 100644
+483 −0
Original line number Diff line number Diff line 
/*-------------------------------------------------------------------------*

 *  File: fs/jffs2/acl.c

 *  POSIX ACL support on JFFS2 FileSystem

 *

 *  Implemented by KaiGai Kohei <kaigai@ak.jp.nec.com>

 *  Copyright (C) 2006 NEC Corporation

 *

 *  For licensing information, see the file 'LICENCE' in the jffs2 directory.

 *-------------------------------------------------------------------------*/

#include <linux/kernel.h>

#include <linux/slab.h>

#include <linux/fs.h>

#include <linux/time.h>

#include <linux/crc32.h>

#include <linux/jffs2.h>

#include <linux/xattr.h>

#include <linux/posix_acl_xattr.h>

#include <linux/mtd/mtd.h>

#include "nodelist.h"



static size_t jffs2_acl_size(int count)

{

	if (count <= 4) {

		return sizeof(jffs2_acl_header)

		       + count * sizeof(jffs2_acl_entry_short);

	} else {

		return sizeof(jffs2_acl_header)

		       + 4 * sizeof(jffs2_acl_entry_short)

		       + (count - 4) * sizeof(jffs2_acl_entry);

	}

}



static int jffs2_acl_count(size_t size)

{

	size_t s;



	size -= sizeof(jffs2_acl_header);

	s = size - 4 * sizeof(jffs2_acl_entry_short);

	if (s < 0) {

		if (size % sizeof(jffs2_acl_entry_short))

			return -1;

		return size / sizeof(jffs2_acl_entry_short);

	} else {

		if (s % sizeof(jffs2_acl_entry))

			return -1;

		return s / sizeof(jffs2_acl_entry) + 4;

	}

}



static struct posix_acl *jffs2_acl_from_medium(const void *value, size_t size)

{

	const char *end = (char *)value + size;

	struct posix_acl *acl;

	uint32_t ver;

	int i, count;



	if (!value)

		return NULL;

	if (size < sizeof(jffs2_acl_header))

		return ERR_PTR(-EINVAL);

	ver = je32_to_cpu(((jffs2_acl_header *)value)->a_version);

	if (ver != JFFS2_ACL_VERSION) {

		JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver);

		return ERR_PTR(-EINVAL);

	}



	value = (char *)value + sizeof(jffs2_acl_header);

	count = jffs2_acl_count(size);

	if (count < 0)

		return ERR_PTR(-EINVAL);

	if (count == 0)

		return NULL;



	acl = posix_acl_alloc(count, GFP_KERNEL);

	if (!acl)

		return ERR_PTR(-ENOMEM);



	for (i=0; i < count; i++) {

		jffs2_acl_entry *entry = (jffs2_acl_entry *)value;

		if ((char *)value + sizeof(jffs2_acl_entry_short) > end)

			goto fail;

		acl->a_entries[i].e_tag = je16_to_cpu(entry->e_tag);

		acl->a_entries[i].e_perm = je16_to_cpu(entry->e_perm);

		switch (acl->a_entries[i].e_tag) {

			case ACL_USER_OBJ:

			case ACL_GROUP_OBJ:

			case ACL_MASK:

			case ACL_OTHER:

				value = (char *)value + sizeof(jffs2_acl_entry_short);

				acl->a_entries[i].e_id = ACL_UNDEFINED_ID;

				break;



			case ACL_USER:

			case ACL_GROUP:

				value = (char *)value + sizeof(jffs2_acl_entry);

				if ((char *)value > end)

					goto fail;

				acl->a_entries[i].e_id = je32_to_cpu(entry->e_id);

				break;



			default:

				goto fail;

		}

	}

	if (value != end)

		goto fail;

	return acl;

 fail:

	posix_acl_release(acl);

	return ERR_PTR(-EINVAL);

}



static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size)

{

	jffs2_acl_header *jffs2_acl;

	char *e;

	size_t i;



	*size = jffs2_acl_size(acl->a_count);

	jffs2_acl = (jffs2_acl_header *)kmalloc(sizeof(jffs2_acl_header)

						+ acl->a_count * sizeof(jffs2_acl_entry),

						GFP_KERNEL);

	if (!jffs2_acl)

		return ERR_PTR(-ENOMEM);

	jffs2_acl->a_version = cpu_to_je32(JFFS2_ACL_VERSION);

	e = (char *)jffs2_acl + sizeof(jffs2_acl_header);

	for (i=0; i < acl->a_count; i++) {

		jffs2_acl_entry *entry = (jffs2_acl_entry *)e;

		entry->e_tag = cpu_to_je16(acl->a_entries[i].e_tag);

		entry->e_perm = cpu_to_je16(acl->a_entries[i].e_perm);

		switch(acl->a_entries[i].e_tag) {

			case ACL_USER:

			case ACL_GROUP:

				entry->e_id = cpu_to_je32(acl->a_entries[i].e_id);

				e += sizeof(jffs2_acl_entry);

				break;



			case ACL_USER_OBJ:

			case ACL_GROUP_OBJ:

			case ACL_MASK:

			case ACL_OTHER:

				e += sizeof(jffs2_acl_entry_short);

				break;



			default:

				goto fail;

		}

	}

	return (char *)jffs2_acl;

 fail:

	kfree(jffs2_acl);

	return ERR_PTR(-EINVAL);

}



static struct posix_acl *jffs2_iget_acl(struct inode *inode, struct posix_acl **i_acl)

{

	struct posix_acl *acl = JFFS2_ACL_NOT_CACHED;



	spin_lock(&inode->i_lock);

	if (*i_acl != JFFS2_ACL_NOT_CACHED)

		acl = posix_acl_dup(*i_acl);

	spin_unlock(&inode->i_lock);

	return acl;

}



static void jffs2_iset_acl(struct inode *inode, struct posix_acl **i_acl, struct posix_acl *acl)

{

	spin_lock(&inode->i_lock);

	if (*i_acl != JFFS2_ACL_NOT_CACHED)

		posix_acl_release(*i_acl);

	*i_acl = posix_acl_dup(acl);

	spin_unlock(&inode->i_lock);

}



static struct posix_acl *jffs2_get_acl(struct inode *inode, int type)

{

	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);

	struct posix_acl *acl;

	char *value = NULL;

	int rc, xprefix;



	switch (type) {

	case ACL_TYPE_ACCESS:

		acl = jffs2_iget_acl(inode, &f->i_acl_access);

		if (acl != JFFS2_ACL_NOT_CACHED)

			return acl;

		xprefix = JFFS2_XPREFIX_ACL_ACCESS;

		break;

	case ACL_TYPE_DEFAULT:

		acl = jffs2_iget_acl(inode, &f->i_acl_default);

		if (acl != JFFS2_ACL_NOT_CACHED)

			return acl;

		xprefix = JFFS2_XPREFIX_ACL_DEFAULT;

		break;

	default:

		return ERR_PTR(-EINVAL);

	}

	rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);

	if (rc > 0) {

		value = kmalloc(rc, GFP_KERNEL);

		if (!value)

			return ERR_PTR(-ENOMEM);

		rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);

	}

	if (rc > 0) {

		acl = jffs2_acl_from_medium(value, rc);

	} else if (rc == -ENODATA || rc == -ENOSYS) {

		acl = NULL;

	} else {

		acl = ERR_PTR(rc);

	}

	if (value)

		kfree(value);

	if (!IS_ERR(acl)) {

		switch (type) {

		case ACL_TYPE_ACCESS:

			jffs2_iset_acl(inode, &f->i_acl_access, acl);

			break;

		case ACL_TYPE_DEFAULT:

			jffs2_iset_acl(inode, &f->i_acl_default, acl);

			break;

		}

	}

	return acl;

}



static int jffs2_set_acl(struct inode *inode, int type, struct posix_acl *acl)

{

	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);

	size_t size = 0;

	char *value = NULL;

	int rc, xprefix;



	if (S_ISLNK(inode->i_mode))

		return -EOPNOTSUPP;



	switch (type) {

	case ACL_TYPE_ACCESS:

		xprefix = JFFS2_XPREFIX_ACL_ACCESS;

		if (acl) {

			mode_t mode = inode->i_mode;

			rc = posix_acl_equiv_mode(acl, &mode);

			if (rc < 0)

				return rc;

			if (inode->i_mode != mode) {

				inode->i_mode = mode;

				jffs2_dirty_inode(inode);

			}

			if (rc == 0)

				acl = NULL;

		}

		break;

	case ACL_TYPE_DEFAULT:

		xprefix = JFFS2_XPREFIX_ACL_DEFAULT;

		if (!S_ISDIR(inode->i_mode))

			return acl ? -EACCES : 0;

		break;

	default:

		return -EINVAL;

	}

	if (acl) {

		value = jffs2_acl_to_medium(acl, &size);

		if (IS_ERR(value))

			return PTR_ERR(value);

	}



	rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);

	if (value)

		kfree(value);

	if (!rc) {

		switch(type) {

		case ACL_TYPE_ACCESS:

			jffs2_iset_acl(inode, &f->i_acl_access, acl);

			break;

		case ACL_TYPE_DEFAULT:

			jffs2_iset_acl(inode, &f->i_acl_default, acl);

			break;

		}

	}

	return rc;

}



static int jffs2_check_acl(struct inode *inode, int mask)

{

	struct posix_acl *acl;

	int rc;



	acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);

	if (IS_ERR(acl))

		return PTR_ERR(acl);

	if (acl) {

		rc = posix_acl_permission(inode, acl, mask);

		posix_acl_release(acl);

		return rc;

	}

	return -EAGAIN;

}



int jffs2_permission(struct inode *inode, int mask, struct nameidata *nd)

{

	return generic_permission(inode, mask, jffs2_check_acl);

}



int jffs2_init_acl(struct inode *inode, struct inode *dir)

{

	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);

	struct posix_acl *acl = NULL, *clone;

	mode_t mode;

	int rc = 0;



	f->i_acl_access = JFFS2_ACL_NOT_CACHED;

	f->i_acl_default = JFFS2_ACL_NOT_CACHED;

	if (!S_ISLNK(inode->i_mode)) {

		acl = jffs2_get_acl(dir, ACL_TYPE_DEFAULT);

		if (IS_ERR(acl))

			return PTR_ERR(acl);

		if (!acl)

			inode->i_mode &= ~current->fs->umask;

	}

	if (acl) {

		if (S_ISDIR(inode->i_mode)) {

			rc = jffs2_set_acl(inode, ACL_TYPE_DEFAULT, acl);

			if (rc)

				goto cleanup;

		}

		clone = posix_acl_clone(acl, GFP_KERNEL);

		rc = -ENOMEM;

		if (!clone)

			goto cleanup;

		mode = inode->i_mode;

		rc = posix_acl_create_masq(clone, &mode);

		if (rc >= 0) {

			inode->i_mode = mode;

			if (rc > 0)

				rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);

		}

		posix_acl_release(clone);

	}

 cleanup:

	posix_acl_release(acl);

	return rc;

}



void jffs2_clear_acl(struct inode *inode)

{

	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);



	if (f->i_acl_access && f->i_acl_access != JFFS2_ACL_NOT_CACHED) {

		posix_acl_release(f->i_acl_access);

		f->i_acl_access = JFFS2_ACL_NOT_CACHED;

	}

	if (f->i_acl_default && f->i_acl_default != JFFS2_ACL_NOT_CACHED) {

		posix_acl_release(f->i_acl_default);

		f->i_acl_default = JFFS2_ACL_NOT_CACHED;

	}

}



int jffs2_acl_chmod(struct inode *inode)

{

	struct posix_acl *acl, *clone;

	int rc;



	if (S_ISLNK(inode->i_mode))

		return -EOPNOTSUPP;

	acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);

	if (IS_ERR(acl) || !acl)

		return PTR_ERR(acl);

	clone = posix_acl_clone(acl, GFP_KERNEL);

	posix_acl_release(acl);

	if (!clone)

		return -ENOMEM;

	rc = posix_acl_chmod_masq(clone, inode->i_mode);

	if (!rc)

		rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);

	posix_acl_release(clone);

	return rc;

}



static size_t jffs2_acl_access_listxattr(struct inode *inode, char *list, size_t list_size,

					 const char *name, size_t name_len)

{

	const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS);



	if (list && retlen <= list_size)

		strcpy(list, POSIX_ACL_XATTR_ACCESS);

	return retlen;

}



static size_t jffs2_acl_default_listxattr(struct inode *inode, char *list, size_t list_size,

					  const char *name, size_t name_len)

{

	const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT);



	if (list && retlen <= list_size)

		strcpy(list, POSIX_ACL_XATTR_DEFAULT);

	return retlen;

}



static int jffs2_acl_getxattr(struct inode *inode, int type, void *buffer, size_t size)

{

	struct posix_acl *acl;

	int rc;



	acl = jffs2_get_acl(inode, type);

	if (IS_ERR(acl))

		return PTR_ERR(acl);

	if (!acl)

		return -ENODATA;

	rc = posix_acl_to_xattr(acl, buffer, size);

	posix_acl_release(acl);



	return rc;

}



static int jffs2_acl_access_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)

{

	if (name[0] != '\0')

		return -EINVAL;

	return jffs2_acl_getxattr(inode, ACL_TYPE_ACCESS, buffer, size);

}



static int jffs2_acl_default_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)

{

	if (name[0] != '\0')

		return -EINVAL;

	return jffs2_acl_getxattr(inode, ACL_TYPE_DEFAULT, buffer, size);

}



static int jffs2_acl_setxattr(struct inode *inode, int type, const void *value, size_t size)

{

	struct posix_acl *acl;

	int rc;



	if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))

		return -EPERM;



	if (value) {

		acl = posix_acl_from_xattr(value, size);

		if (IS_ERR(acl))

			return PTR_ERR(acl);

		if (acl) {

			rc = posix_acl_valid(acl);

			if (rc)

				goto out;

		}

	} else {

		acl = NULL;

	}

	rc = jffs2_set_acl(inode, type, acl);

 out:

	posix_acl_release(acl);

	return rc;

}



static int jffs2_acl_access_setxattr(struct inode *inode, const char *name,

				     const void *buffer, size_t size, int flags)

{

	if (name[0] != '\0')

		return -EINVAL;

	return jffs2_acl_setxattr(inode, ACL_TYPE_ACCESS, buffer, size);

}



static int jffs2_acl_default_setxattr(struct inode *inode, const char *name,

				      const void *buffer, size_t size, int flags)

{

	if (name[0] != '\0')

		return -EINVAL;

	return jffs2_acl_setxattr(inode, ACL_TYPE_DEFAULT, buffer, size);

}



struct xattr_handler jffs2_acl_access_xattr_handler = {

	.prefix	= POSIX_ACL_XATTR_ACCESS,

	.list	= jffs2_acl_access_listxattr,

	.get	= jffs2_acl_access_getxattr,

	.set	= jffs2_acl_access_setxattr,

};



struct xattr_handler jffs2_acl_default_xattr_handler = {

	.prefix	= POSIX_ACL_XATTR_DEFAULT,

	.list	= jffs2_acl_default_listxattr,

	.get	= jffs2_acl_default_getxattr,

	.set	= jffs2_acl_default_setxattr,

};

fs/jffs2/acl.h

0 → 100644
+46 −0
Original line number Diff line number Diff line 
/*-------------------------------------------------------------------------*

 *  File: fs/jffs2/acl.h

 *  POSIX ACL support on JFFS2 FileSystem

 *

 *  Implemented by KaiGai Kohei <kaigai@ak.jp.nec.com>

 *  Copyright (C) 2006 NEC Corporation

 *

 *  For licensing information, see the file 'LICENCE' in the jffs2 directory.

 *-------------------------------------------------------------------------*/

typedef struct {

	jint16_t	e_tag;

	jint16_t	e_perm;

	jint32_t	e_id;

} jffs2_acl_entry;



typedef struct {

	jint16_t	e_tag;

	jint16_t	e_perm;

} jffs2_acl_entry_short;



typedef struct {

	jint32_t	a_version;

} jffs2_acl_header;



#ifdef __KERNEL__

#ifdef CONFIG_JFFS2_FS_POSIX_ACL



#define JFFS2_ACL_NOT_CACHED ((void *)-1)



extern int jffs2_permission(struct inode *, int, struct nameidata *);

extern int jffs2_acl_chmod(struct inode *);

extern int jffs2_init_acl(struct inode *, struct inode *);

extern void jffs2_clear_acl(struct inode *);



extern struct xattr_handler jffs2_acl_access_xattr_handler;

extern struct xattr_handler jffs2_acl_default_xattr_handler;



#else



#define jffs2_permission NULL

#define jffs2_acl_chmod(inode)		(0)

#define jffs2_init_acl(inode,dir)	(0)

#define jffs2_clear_acl(inode)



#endif	/* CONFIG_JFFS2_FS_POSIX_ACL */

#endif	/* __KERNEL__ */

fs/jffs2/build.c

+2 −0
Original line number Diff line number Diff line
@@ -160,6 +160,7 @@ static int jffs2_build_filesystem(struct jffs2_sb_info *c) 
		ic->scan_dents = NULL;

		cond_resched();

	}

	jffs2_build_xattr_subsystem(c);

	c->flags &= ~JFFS2_SB_FLAG_BUILDING;



	dbg_fsbuild("FS build complete\n");
@@ -178,6 +179,7 @@ exit: 
				jffs2_free_full_dirent(fd);

			}

		}

		jffs2_clear_xattr_subsystem(c);

	}



	return ret;