xfs: fix validation in attr log item recovery

Before we start fixing all the complaints about memcpy'ing log items
around, let's fix some inadequate validation in the xattr log item
recovery code and get rid of the (now trivial) copy_format function.
Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
Reviewed-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NAllison Henderson <allison.henderson@oracle.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>

fs/xfs/xfs_attr_item.c

@@ -245,28 +245,6 @@ xfs_attri_init(
 	return attrip;
 }
 
-/*
- * Copy an attr format buffer from the given buf, and into the destination attr
- * format structure.
- */
-STATIC int
-xfs_attri_copy_format(
-	struct xfs_log_iovec		*buf,
-	struct xfs_attri_log_format	*dst_attr_fmt)
-{
-	struct xfs_attri_log_format	*src_attr_fmt = buf->i_addr;
-	size_t				len;
-
-	len = sizeof(struct xfs_attri_log_format);
-	if (buf->i_len != len) {
-		XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, NULL);
-		return -EFSCORRUPTED;
-	}
-
-	memcpy((char *)dst_attr_fmt, (char *)src_attr_fmt, len);
-	return 0;
-}
-
 static inline struct xfs_attrd_log_item *ATTRD_ITEM(struct xfs_log_item *lip)
 {
 	return container_of(lip, struct xfs_attrd_log_item, attrd_item);
@@ -731,24 +709,44 @@ xlog_recover_attri_commit_pass2(
 	struct xfs_attri_log_nameval	*nv;
 	const void			*attr_value = NULL;
 	const void			*attr_name;
-	int                             error;
+	size_t				len;
 
 	attri_formatp = item->ri_buf[0].i_addr;
 	attr_name = item->ri_buf[1].i_addr;
 
 	/* Validate xfs_attri_log_format before the large memory allocation */
+	len = sizeof(struct xfs_attri_log_format);
+	if (item->ri_buf[0].i_len != len) {
+		XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp);
+		return -EFSCORRUPTED;
+	}
+
 	if (!xfs_attri_validate(mp, attri_formatp)) {
 		XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp);
 		return -EFSCORRUPTED;
 	}
 
+	/* Validate the attr name */
+	if (item->ri_buf[1].i_len !=
+			xlog_calc_iovec_len(attri_formatp->alfi_name_len)) {
+		XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp);
+		return -EFSCORRUPTED;
+	}
+
 	if (!xfs_attr_namecheck(attr_name, attri_formatp->alfi_name_len)) {
 		XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp);
 		return -EFSCORRUPTED;
 	}
 
-	if (attri_formatp->alfi_value_len)
+	/* Validate the attr value, if present */
+	if (attri_formatp->alfi_value_len != 0) {
+		if (item->ri_buf[2].i_len != xlog_calc_iovec_len(attri_formatp->alfi_value_len)) {
+			XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp);
+			return -EFSCORRUPTED;
+		}
+
 		attr_value = item->ri_buf[2].i_addr;
+	}
 
 	/*
 	 * Memory alloc failure will cause replay to abort.  We attach the
@@ -760,9 +758,7 @@ xlog_recover_attri_commit_pass2(
 			attri_formatp->alfi_value_len);
 
 	attrip = xfs_attri_init(mp, nv);
-	error = xfs_attri_copy_format(&item->ri_buf[0], &attrip->attri_format);
-	if (error)
-		goto out;
+	memcpy(&attrip->attri_format, attri_formatp, len);
 
 	/*
 	 * The ATTRI has two references. One for the ATTRD and one for ATTRI to
@@ -774,10 +770,6 @@ xlog_recover_attri_commit_pass2(
 	xfs_attri_release(attrip);
 	xfs_attri_log_nameval_put(nv);
 	return 0;
-out:
-	xfs_attri_item_free(attrip);
-	xfs_attri_log_nameval_put(nv);
-	return error;
 }
 
 /*