1 files changed, 283 insertions, 0 deletions
diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
new file mode 100644
index 000000000..c544951a0
--- /dev/null
+++ b/fs/xfs/xfs_acl.c
@@ -0,0 +1,283 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2008, Christoph Hellwig
+ * All Rights Reserved.
+ */
+#include "xfs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_inode.h"
+#include "xfs_attr.h"
+#include "xfs_trace.h"
+#include "xfs_error.h"
+#include "xfs_acl.h"
+#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
+
+#include <linux/posix_acl_xattr.h>
+
+/*
+ * Locking scheme:
+ *  - all ACL updates are protected by inode->i_mutex, which is taken before
+ *    calling into this file.
+ */
+
+STATIC struct posix_acl *
+xfs_acl_from_disk(
+	struct xfs_mount	*mp,
+	const struct xfs_acl	*aclp,
+	int			len,
+	int			max_entries)
+{
+	struct posix_acl_entry *acl_e;
+	struct posix_acl *acl;
+	const struct xfs_acl_entry *ace;
+	unsigned int count, i;
+
+	if (len < sizeof(*aclp)) {
+		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
+				len);
+		return ERR_PTR(-EFSCORRUPTED);
+	}
+
+	count = be32_to_cpu(aclp->acl_cnt);
+	if (count > max_entries || XFS_ACL_SIZE(count) != len) {
+		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
+				len);
+		return ERR_PTR(-EFSCORRUPTED);
+	}
+
+	acl = posix_acl_alloc(count, GFP_KERNEL);
+	if (!acl)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < count; i++) {
+		acl_e = &acl->a_entries[i];
+		ace = &aclp->acl_entry[i];
+
+		/*
+		 * The tag is 32 bits on disk and 16 bits in core.
+		 *
+		 * Because every access to it goes through the core
+		 * format first this is not a problem.
+		 */
+		acl_e->e_tag = be32_to_cpu(ace->ae_tag);
+		acl_e->e_perm = be16_to_cpu(ace->ae_perm);
+
+		switch (acl_e->e_tag) {
+		case ACL_USER:
+			acl_e->e_uid = make_kuid(&init_user_ns,
+						 be32_to_cpu(ace->ae_id));
+			break;
+		case ACL_GROUP:
+			acl_e->e_gid = make_kgid(&init_user_ns,
+						 be32_to_cpu(ace->ae_id));
+			break;
+		case ACL_USER_OBJ:
+		case ACL_GROUP_OBJ:
+		case ACL_MASK:
+		case ACL_OTHER:
+			break;
+		default:
+			goto fail;
+		}
+	}
+	return acl;
+
+fail:
+	posix_acl_release(acl);
+	return ERR_PTR(-EINVAL);
+}
+
+STATIC void
+xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
+{
+	const struct posix_acl_entry *acl_e;
+	struct xfs_acl_entry *ace;
+	int i;
+
+	aclp->acl_cnt = cpu_to_be32(acl->a_count);
+	for (i = 0; i < acl->a_count; i++) {
+		ace = &aclp->acl_entry[i];
+		acl_e = &acl->a_entries[i];
+
+		ace->ae_tag = cpu_to_be32(acl_e->e_tag);
+		switch (acl_e->e_tag) {
+		case ACL_USER:
+			ace->ae_id = cpu_to_be32(
+					from_kuid(&init_user_ns, acl_e->e_uid));
+			break;
+		case ACL_GROUP:
+			ace->ae_id = cpu_to_be32(
+					from_kgid(&init_user_ns, acl_e->e_gid));
+			break;
+		default:
+			ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
+			break;
+		}
+
+		ace->ae_perm = cpu_to_be16(acl_e->e_perm);
+	}
+}
+
+struct posix_acl *
+xfs_get_acl(struct inode *inode, int type)
+{
+	struct xfs_inode	*ip = XFS_I(inode);
+	struct xfs_mount	*mp = ip->i_mount;
+	struct posix_acl	*acl = NULL;
+	struct xfs_da_args	args = {
+		.dp		= ip,
+		.attr_filter	= XFS_ATTR_ROOT,
+		.valuelen	= XFS_ACL_MAX_SIZE(mp),
+	};
+	int			error;
+
+	trace_xfs_get_acl(ip);
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		args.name = SGI_ACL_FILE;
+		break;
+	case ACL_TYPE_DEFAULT:
+		args.name = SGI_ACL_DEFAULT;
+		break;
+	default:
+		BUG();
+	}
+	args.namelen = strlen(args.name);
+
+	/*
+	 * If the attribute doesn't exist make sure we have a negative cache
+	 * entry, for any other error assume it is transient.
+	 */
+	error = xfs_attr_get(&args);
+	if (!error) {
+		acl = xfs_acl_from_disk(mp, args.value, args.valuelen,
+					XFS_ACL_MAX_ENTRIES(mp));
+	} else if (error != -ENOATTR) {
+		acl = ERR_PTR(error);
+	}
+
+	kmem_free(args.value);
+	return acl;
+}
+
+int
+__xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+{
+	struct xfs_inode	*ip = XFS_I(inode);
+	struct xfs_da_args	args = {
+		.dp		= ip,
+		.attr_filter	= XFS_ATTR_ROOT,
+	};
+	int			error;
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		args.name = SGI_ACL_FILE;
+		break;
+	case ACL_TYPE_DEFAULT:
+		if (!S_ISDIR(inode->i_mode))
+			return acl ? -EACCES : 0;
+		args.name = SGI_ACL_DEFAULT;
+		break;
+	default:
+		return -EINVAL;
+	}
+	args.namelen = strlen(args.name);
+
+	if (acl) {
+		args.valuelen = XFS_ACL_SIZE(acl->a_count);
+		args.value = kvzalloc(args.valuelen, GFP_KERNEL);
+		if (!args.value)
+			return -ENOMEM;
+		xfs_acl_to_disk(args.value, acl);
+	}
+
+	error = xfs_attr_set(&args);
+	kmem_free(args.value);
+
+	/*
+	 * If the attribute didn't exist to start with that's fine.
+	 */
+	if (!acl && error == -ENOATTR)
+		error = 0;
+	if (!error)
+		set_cached_acl(inode, type, acl);
+	return error;
+}
+
+static int
+xfs_set_mode(struct inode *inode, umode_t mode)
+{
+	int error = 0;
+
+	if (mode != inode->i_mode) {
+		struct iattr iattr;
+
+		iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
+		iattr.ia_mode = mode;
+		iattr.ia_ctime = current_time(inode);
+
+		error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
+	}
+
+	return error;
+}
+
+int
+xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+{
+	umode_t mode;
+	bool set_mode = false;
+	int error = 0;
+
+	if (!acl)
+		goto set_acl;
+
+	error = -E2BIG;
+	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
+		return error;
+
+	if (type == ACL_TYPE_ACCESS) {
+		error = posix_acl_update_mode(inode, &mode, &acl);
+		if (error)
+			return error;
+		set_mode = true;
+	}
+
+ set_acl:
+	error =  __xfs_set_acl(inode, acl, type);
+	if (error)
+		return error;
+
+	/*
+	 * We set the mode after successfully updating the ACL xattr because the
+	 * xattr update can fail at ENOSPC and we don't want to change the mode
+	 * if the ACL update hasn't been applied.
+	 */
+	if (set_mode)
+		error = xfs_set_mode(inode, mode);
+
+	return error;
+}
+
+/*
+ * Invalidate any cached ACLs if the user has bypassed the ACL interface.
+ * We don't validate the content whatsoever so it is caller responsibility to
+ * provide data in valid format and ensure i_mode is consistent.
+ */
+void
+xfs_forget_acl(
+	struct inode		*inode,
+	const char		*name)
+{
+	if (!strcmp(name, SGI_ACL_FILE))
+		forget_cached_acl(inode, ACL_TYPE_ACCESS);
+	else if (!strcmp(name, SGI_ACL_DEFAULT))
+		forget_cached_acl(inode, ACL_TYPE_DEFAULT);
+}