From 128f24d5d9def3c47b6b659b2454f0426a347144 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <darrick.wong@oracle.com>
Date: Tue, 21 Jun 2016 11:53:28 +1000
Subject: xfs: check for a valid error_tag in errortag_add

Currently we don't check the error_tag when someone's trying to set up
error injection testing.  If userspace passes in a value we don't know
about, send back an error.  This will help xfstests to _notrun a test
that uses error injection to test things like log replay.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/xfs/xfs_error.c b/fs/xfs/xfs_error.c
index 88693a9..355619a 100644
--- a/fs/xfs/xfs_error.c
+++ b/fs/xfs/xfs_error.c
@@ -61,6 +61,9 @@ xfs_errortag_add(int error_tag, xfs_mount_t *mp)
 	int len;
 	int64_t fsid;
 
+	if (error_tag >= XFS_ERRTAG_MAX)
+		return -EINVAL;
+
 	memcpy(&fsid, mp->m_fixedfsid, sizeof(xfs_fsid_t));
 
 	for (i = 0; i < XFS_NUM_INJECT_ERROR; i++)  {
-- 
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