Commit 5d92b75c authored by Andreas Gruenbacher's avatar Andreas Gruenbacher Committed by Al Viro
Browse files

xfs: Change how listxattr generates synthetic attributes 



Instead of adding the synthesized POSIX ACL attribute names after listing all
non-synthesized attributes, generate them immediately when listing the
non-synthesized attributes.

In addition, merge xfs_xattr_put_listent and xfs_xattr_put_listent_sizes to
ensure that the list size is computed correctly; the split version was
overestimating the list size for non-root users.

Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 786534b9

fs/xfs/xfs_acl.c

+0 −23
Original line number Diff line number Diff line
@@ -252,29 +252,6 @@ xfs_set_mode(struct inode *inode, umode_t mode) 
	return error;

}



static int

xfs_acl_exists(struct inode *inode, unsigned char *name)

{

	int len = XFS_ACL_MAX_SIZE(XFS_M(inode->i_sb));



	return (xfs_attr_get(XFS_I(inode), name, NULL, &len,

			    ATTR_ROOT|ATTR_KERNOVAL) == 0);

}



int

posix_acl_access_exists(struct inode *inode)

{

	return xfs_acl_exists(inode, SGI_ACL_FILE);

}



int

posix_acl_default_exists(struct inode *inode)

{

	if (!S_ISDIR(inode->i_mode))

		return 0;

	return xfs_acl_exists(inode, SGI_ACL_DEFAULT);

}



int

xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)

{

fs/xfs/xfs_acl.h

+0 −4
Original line number Diff line number Diff line
@@ -24,16 +24,12 @@ struct posix_acl; 
#ifdef CONFIG_XFS_POSIX_ACL

extern struct posix_acl *xfs_get_acl(struct inode *inode, int type);

extern int xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type);

extern int posix_acl_access_exists(struct inode *inode);

extern int posix_acl_default_exists(struct inode *inode);

#else

static inline struct posix_acl *xfs_get_acl(struct inode *inode, int type)

{

	return NULL;

}

# define xfs_set_acl					NULL

# define posix_acl_access_exists(inode)			0

# define posix_acl_default_exists(inode)		0

#endif /* CONFIG_XFS_POSIX_ACL */



extern void xfs_forget_acl(struct inode *inode, const char *name, int xflags);

fs/xfs/xfs_xattr.c

+59 −78
Original line number Diff line number Diff line
@@ -129,47 +129,19 @@ const struct xattr_handler *xfs_xattr_handlers[] = { 
	NULL

};



static unsigned int xfs_xattr_prefix_len(int flags)

{

	if (flags & XFS_ATTR_SECURE)

		return sizeof("security");

	else if (flags & XFS_ATTR_ROOT)

		return sizeof("trusted");

	else

		return sizeof("user");

}



static const char *xfs_xattr_prefix(int flags)

{

	if (flags & XFS_ATTR_SECURE)

		return xfs_xattr_security_handler.prefix;

	else if (flags & XFS_ATTR_ROOT)

		return xfs_xattr_trusted_handler.prefix;

	else

		return xfs_xattr_user_handler.prefix;

}



static int

xfs_xattr_put_listent(

__xfs_xattr_put_listent(

	struct xfs_attr_list_context *context,

	int		flags,

	char *prefix,

	int prefix_len,

	unsigned char *name,

	int		namelen,

	int		valuelen,

	unsigned char	*value)

	int namelen)

{

	unsigned int prefix_len = xfs_xattr_prefix_len(flags);

	char *offset;

	int arraytop;



	ASSERT(context->count >= 0);



	/*

	 * Only show root namespace entries if we are actually allowed to

	 * see them.

	 */

	if ((flags & XFS_ATTR_ROOT) && !capable(CAP_SYS_ADMIN))

		return 0;

	if (!context->alist)

		goto compute_size;



	arraytop = context->count + prefix_len + namelen + 1;

	if (arraytop > context->firstu) {
@@ -177,17 +149,19 @@ xfs_xattr_put_listent( 
		return 1;

	}

	offset = (char *)context->alist + context->count;

	strncpy(offset, xfs_xattr_prefix(flags), prefix_len);

	strncpy(offset, prefix, prefix_len);

	offset += prefix_len;

	strncpy(offset, (char *)name, namelen);			/* real name */

	offset += namelen;

	*offset = '\0';



compute_size:

	context->count += prefix_len + namelen + 1;

	return 0;

}



static int

xfs_xattr_put_listent_sizes(

xfs_xattr_put_listent(

	struct xfs_attr_list_context *context,

	int		flags,

	unsigned char	*name,
@@ -195,24 +169,55 @@ xfs_xattr_put_listent_sizes( 
	int		valuelen,

	unsigned char	*value)

{

	context->count += xfs_xattr_prefix_len(flags) + namelen + 1;

	return 0;

}

	char *prefix;

	int prefix_len;



static int

list_one_attr(const char *name, const size_t len, void *data,

		size_t size, ssize_t *result)

{

	char *p = data + *result;

	ASSERT(context->count >= 0);



	*result += len;

	if (!size)

		return 0;

	if (*result > size)

		return -ERANGE;

	if (flags & XFS_ATTR_ROOT) {

#ifdef CONFIG_XFS_POSIX_ACL

		if (namelen == SGI_ACL_FILE_SIZE &&

		    strncmp(name, SGI_ACL_FILE,

			    SGI_ACL_FILE_SIZE) == 0) {

			int ret = __xfs_xattr_put_listent(

					context, XATTR_SYSTEM_PREFIX,

					XATTR_SYSTEM_PREFIX_LEN,

					XATTR_POSIX_ACL_ACCESS,

					strlen(XATTR_POSIX_ACL_ACCESS));

			if (ret)

				return ret;

		} else if (namelen == SGI_ACL_DEFAULT_SIZE &&

			 strncmp(name, SGI_ACL_DEFAULT,

				 SGI_ACL_DEFAULT_SIZE) == 0) {

			int ret = __xfs_xattr_put_listent(

					context, XATTR_SYSTEM_PREFIX,

					XATTR_SYSTEM_PREFIX_LEN,

					XATTR_POSIX_ACL_DEFAULT,

					strlen(XATTR_POSIX_ACL_DEFAULT));

			if (ret)

				return ret;

		}

#endif



	strcpy(p, name);

		/*

		 * Only show root namespace entries if we are actually allowed to

		 * see them.

		 */

		if (!capable(CAP_SYS_ADMIN))

			return 0;



		prefix = XATTR_TRUSTED_PREFIX;

		prefix_len = XATTR_TRUSTED_PREFIX_LEN;

	} else if (flags & XFS_ATTR_SECURE) {

		prefix = XATTR_SECURITY_PREFIX;

		prefix_len = XATTR_SECURITY_PREFIX_LEN;

	} else {

		prefix = XATTR_USER_PREFIX;

		prefix_len = XATTR_USER_PREFIX_LEN;

	}



	return __xfs_xattr_put_listent(context, prefix, prefix_len, name,

				       namelen);

}



ssize_t
@@ -221,7 +226,6 @@ xfs_vn_listxattr(struct dentry *dentry, char *data, size_t size) 
	struct xfs_attr_list_context context;

	struct attrlist_cursor_kern cursor = { 0 };

	struct inode		*inode = d_inode(dentry);

	int			error;



	/*

	 * First read the regular on-disk attributes.
@@ -230,37 +234,14 @@ xfs_vn_listxattr(struct dentry *dentry, char *data, size_t size) 
	context.dp = XFS_I(inode);

	context.cursor = &cursor;

	context.resynch = 1;

	context.alist = data;

	context.alist = size ? data : NULL;

	context.bufsize = size;

	context.firstu = context.bufsize;



	if (size)

	context.put_listent = xfs_xattr_put_listent;

	else

		context.put_listent = xfs_xattr_put_listent_sizes;



	xfs_attr_list_int(&context);

	if (context.count < 0)

		return -ERANGE;



	/*

	 * Then add the two synthetic ACL attributes.

	 */

	if (posix_acl_access_exists(inode)) {

		error = list_one_attr(XATTR_NAME_POSIX_ACL_ACCESS,

				strlen(XATTR_NAME_POSIX_ACL_ACCESS) + 1,

				data, size, &context.count);

		if (error)

			return error;

	}



	if (posix_acl_default_exists(inode)) {

		error = list_one_attr(XATTR_NAME_POSIX_ACL_DEFAULT,

				strlen(XATTR_NAME_POSIX_ACL_DEFAULT) + 1,

				data, size, &context.count);

		if (error)

			return error;

	}



	return context.count;

}

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