1 files changed, 308 insertions, 0 deletions
diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
new file mode 100644
index 000000000..c325a28b8
--- /dev/null
+++ b/fs/xfs/xfs_xattr.c
@@ -0,0 +1,308 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2008 Christoph Hellwig.
+ * Portions Copyright (C) 2000-2008 Silicon Graphics, Inc.
+ */
+
+#include "xfs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_da_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_inode.h"
+#include "xfs_da_btree.h"
+#include "xfs_attr.h"
+#include "xfs_acl.h"
+#include "xfs_log.h"
+#include "xfs_xattr.h"
+
+#include <linux/posix_acl_xattr.h>
+
+/*
+ * Get permission to use log-assisted atomic exchange of file extents.
+ *
+ * Callers must not be running any transactions or hold any inode locks, and
+ * they must release the permission by calling xlog_drop_incompat_feat
+ * when they're done.
+ */
+static inline int
+xfs_attr_grab_log_assist(
+	struct xfs_mount	*mp)
+{
+	int			error = 0;
+
+	/*
+	 * Protect ourselves from an idle log clearing the logged xattrs log
+	 * incompat feature bit.
+	 */
+	xlog_use_incompat_feat(mp->m_log);
+
+	/*
+	 * If log-assisted xattrs are already enabled, the caller can use the
+	 * log assisted swap functions with the log-incompat reference we got.
+	 */
+	if (xfs_sb_version_haslogxattrs(&mp->m_sb))
+		return 0;
+
+	/* Enable log-assisted xattrs. */
+	error = xfs_add_incompat_log_feature(mp,
+			XFS_SB_FEAT_INCOMPAT_LOG_XATTRS);
+	if (error)
+		goto drop_incompat;
+
+	xfs_warn_mount(mp, XFS_OPSTATE_WARNED_LARP,
+ "EXPERIMENTAL logged extended attributes feature in use. Use at your own risk!");
+
+	return 0;
+drop_incompat:
+	xlog_drop_incompat_feat(mp->m_log);
+	return error;
+}
+
+static inline void
+xfs_attr_rele_log_assist(
+	struct xfs_mount	*mp)
+{
+	xlog_drop_incompat_feat(mp->m_log);
+}
+
+static inline bool
+xfs_attr_want_log_assist(
+	struct xfs_mount	*mp)
+{
+#ifdef DEBUG
+	/* Logged xattrs require a V5 super for log_incompat */
+	return xfs_has_crc(mp) && xfs_globals.larp;
+#else
+	return false;
+#endif
+}
+
+/*
+ * Set or remove an xattr, having grabbed the appropriate logging resources
+ * prior to calling libxfs.
+ */
+int
+xfs_attr_change(
+	struct xfs_da_args	*args)
+{
+	struct xfs_mount	*mp = args->dp->i_mount;
+	bool			use_logging = false;
+	int			error;
+
+	ASSERT(!(args->op_flags & XFS_DA_OP_LOGGED));
+
+	if (xfs_attr_want_log_assist(mp)) {
+		error = xfs_attr_grab_log_assist(mp);
+		if (error)
+			return error;
+
+		args->op_flags |= XFS_DA_OP_LOGGED;
+		use_logging = true;
+	}
+
+	error = xfs_attr_set(args);
+
+	if (use_logging)
+		xfs_attr_rele_log_assist(mp);
+	return error;
+}
+
+
+static int
+xfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused,
+		struct inode *inode, const char *name, void *value, size_t size)
+{
+	struct xfs_da_args	args = {
+		.dp		= XFS_I(inode),
+		.attr_filter	= handler->flags,
+		.name		= name,
+		.namelen	= strlen(name),
+		.value		= value,
+		.valuelen	= size,
+	};
+	int			error;
+
+	error = xfs_attr_get(&args);
+	if (error)
+		return error;
+	return args.valuelen;
+}
+
+static int
+xfs_xattr_set(const struct xattr_handler *handler,
+	      struct user_namespace *mnt_userns, struct dentry *unused,
+	      struct inode *inode, const char *name, const void *value,
+	      size_t size, int flags)
+{
+	struct xfs_da_args	args = {
+		.dp		= XFS_I(inode),
+		.attr_filter	= handler->flags,
+		.attr_flags	= flags,
+		.name		= name,
+		.namelen	= strlen(name),
+		.value		= (void *)value,
+		.valuelen	= size,
+	};
+	int			error;
+
+	error = xfs_attr_change(&args);
+	if (!error && (handler->flags & XFS_ATTR_ROOT))
+		xfs_forget_acl(inode, name);
+	return error;
+}
+
+static const struct xattr_handler xfs_xattr_user_handler = {
+	.prefix	= XATTR_USER_PREFIX,
+	.flags	= 0, /* no flags implies user namespace */
+	.get	= xfs_xattr_get,
+	.set	= xfs_xattr_set,
+};
+
+static const struct xattr_handler xfs_xattr_trusted_handler = {
+	.prefix	= XATTR_TRUSTED_PREFIX,
+	.flags	= XFS_ATTR_ROOT,
+	.get	= xfs_xattr_get,
+	.set	= xfs_xattr_set,
+};
+
+static const struct xattr_handler xfs_xattr_security_handler = {
+	.prefix	= XATTR_SECURITY_PREFIX,
+	.flags	= XFS_ATTR_SECURE,
+	.get	= xfs_xattr_get,
+	.set	= xfs_xattr_set,
+};
+
+const struct xattr_handler *xfs_xattr_handlers[] = {
+	&xfs_xattr_user_handler,
+	&xfs_xattr_trusted_handler,
+	&xfs_xattr_security_handler,
+#ifdef CONFIG_XFS_POSIX_ACL
+	&posix_acl_access_xattr_handler,
+	&posix_acl_default_xattr_handler,
+#endif
+	NULL
+};
+
+static void
+__xfs_xattr_put_listent(
+	struct xfs_attr_list_context *context,
+	char *prefix,
+	int prefix_len,
+	unsigned char *name,
+	int namelen)
+{
+	char *offset;
+	int arraytop;
+
+	if (context->count < 0 || context->seen_enough)
+		return;
+
+	if (!context->buffer)
+		goto compute_size;
+
+	arraytop = context->count + prefix_len + namelen + 1;
+	if (arraytop > context->firstu) {
+		context->count = -1;	/* insufficient space */
+		context->seen_enough = 1;
+		return;
+	}
+	offset = context->buffer + context->count;
+	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;
+}
+
+static void
+xfs_xattr_put_listent(
+	struct xfs_attr_list_context *context,
+	int		flags,
+	unsigned char	*name,
+	int		namelen,
+	int		valuelen)
+{
+	char *prefix;
+	int prefix_len;
+
+	ASSERT(context->count >= 0);
+
+	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) {
+			__xfs_xattr_put_listent(
+					context, XATTR_SYSTEM_PREFIX,
+					XATTR_SYSTEM_PREFIX_LEN,
+					XATTR_POSIX_ACL_ACCESS,
+					strlen(XATTR_POSIX_ACL_ACCESS));
+		} else if (namelen == SGI_ACL_DEFAULT_SIZE &&
+			 strncmp(name, SGI_ACL_DEFAULT,
+				 SGI_ACL_DEFAULT_SIZE) == 0) {
+			__xfs_xattr_put_listent(
+					context, XATTR_SYSTEM_PREFIX,
+					XATTR_SYSTEM_PREFIX_LEN,
+					XATTR_POSIX_ACL_DEFAULT,
+					strlen(XATTR_POSIX_ACL_DEFAULT));
+		}
+#endif
+
+		/*
+		 * Only show root namespace entries if we are actually allowed to
+		 * see them.
+		 */
+		if (!capable(CAP_SYS_ADMIN))
+			return;
+
+		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;
+	}
+
+	__xfs_xattr_put_listent(context, prefix, prefix_len, name,
+				namelen);
+	return;
+}
+
+ssize_t
+xfs_vn_listxattr(
+	struct dentry	*dentry,
+	char		*data,
+	size_t		size)
+{
+	struct xfs_attr_list_context context;
+	struct inode	*inode = d_inode(dentry);
+	int		error;
+
+	/*
+	 * First read the regular on-disk attributes.
+	 */
+	memset(&context, 0, sizeof(context));
+	context.dp = XFS_I(inode);
+	context.resynch = 1;
+	context.buffer = size ? data : NULL;
+	context.bufsize = size;
+	context.firstu = context.bufsize;
+	context.put_listent = xfs_xattr_put_listent;
+
+	error = xfs_attr_list(&context);
+	if (error)
+		return error;
+	if (context.count < 0)
+		return -ERANGE;
+
+	return context.count;
+}