1 files changed, 270 insertions, 0 deletions
diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
new file mode 100644
index 000000000..8039e3514
--- /dev/null
+++ b/fs/xfs/xfs_acl.c
@@ -0,0 +1,270 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2008, Christoph Hellwig
+ * All Rights Reserved.
+ */
+#include "xfs.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_acl.h"
+#include "xfs_attr.h"
+#include "xfs_trace.h"
+#include <linux/slab.h>
+#include <linux/xattr.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(
+	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))
+		return ERR_PTR(-EFSCORRUPTED);
+	count = be32_to_cpu(aclp->acl_cnt);
+	if (count > max_entries || XFS_ACL_SIZE(count) != 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 = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id));
+			break;
+		case ACL_GROUP:
+			acl_e->e_gid = xfs_gid_to_kgid(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(xfs_kuid_to_uid(acl_e->e_uid));
+			break;
+		case ACL_GROUP:
+			ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(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 posix_acl *acl = NULL;
+	struct xfs_acl *xfs_acl;
+	unsigned char *ea_name;
+	int error;
+	int len;
+
+	trace_xfs_get_acl(ip);
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		ea_name = SGI_ACL_FILE;
+		break;
+	case ACL_TYPE_DEFAULT:
+		ea_name = SGI_ACL_DEFAULT;
+		break;
+	default:
+		BUG();
+	}
+
+	/*
+	 * If we have a cached ACLs value just return it, not need to
+	 * go out to the disk.
+	 */
+	len = XFS_ACL_MAX_SIZE(ip->i_mount);
+	xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
+	if (!xfs_acl)
+		return ERR_PTR(-ENOMEM);
+
+	error = xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
+							&len, ATTR_ROOT);
+	if (error) {
+		/*
+		 * If the attribute doesn't exist make sure we have a negative
+		 * cache entry, for any other error assume it is transient.
+		 */
+		if (error != -ENOATTR)
+			acl = ERR_PTR(error);
+	} else  {
+		acl = xfs_acl_from_disk(xfs_acl, len,
+					XFS_ACL_MAX_ENTRIES(ip->i_mount));
+	}
+	kmem_free(xfs_acl);
+	return acl;
+}
+
+int
+__xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+{
+	struct xfs_inode *ip = XFS_I(inode);
+	unsigned char *ea_name;
+	int error;
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		ea_name = SGI_ACL_FILE;
+		break;
+	case ACL_TYPE_DEFAULT:
+		if (!S_ISDIR(inode->i_mode))
+			return acl ? -EACCES : 0;
+		ea_name = SGI_ACL_DEFAULT;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (acl) {
+		struct xfs_acl *xfs_acl;
+		int len = XFS_ACL_MAX_SIZE(ip->i_mount);
+
+		xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
+		if (!xfs_acl)
+			return -ENOMEM;
+
+		xfs_acl_to_disk(xfs_acl, acl);
+
+		/* subtract away the unused acl entries */
+		len -= sizeof(struct xfs_acl_entry) *
+			 (XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);
+
+		error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
+				len, ATTR_ROOT);
+
+		kmem_free(xfs_acl);
+	} else {
+		/*
+		 * A NULL ACL argument means we want to remove the ACL.
+		 */
+		error = xfs_attr_remove(ip, ea_name, ATTR_ROOT);
+
+		/*
+		 * If the attribute didn't exist to start with that's fine.
+		 */
+		if (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;
+}