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-rw-r--r--fs/xfs/xfs_xattr.c308
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;
+}