linux-ext4 - [PATCH 9/9] ext4: remove the access_ok() check in ext4_ioctl_get_es

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Message-Id: <20200523073016.2944131-10-hch@lst.de>
Date:   Sat, 23 May 2020 09:30:16 +0200
From:   Christoph Hellwig <hch@....de>
To:     linux-ext4@...r.kernel.org, viro@...iv.linux.org.uk
Cc:     jack@...e.cz, tytso@....edu, adilger@...ger.ca,
        riteshh@...ux.ibm.com, amir73il@...il.com,
        linux-fsdevel@...r.kernel.org, linux-unionfs@...r.kernel.org
Subject: [PATCH 9/9] ext4: remove the access_ok() check in ext4_ioctl_get_es_cache

access_ok just checks we are fed a proper user pointer.  We also do that
in copy_to_user itself, so no need to do this early.

Signed-off-by: Christoph Hellwig <hch@....de>
Reviewed-by: Ritesh Harjani <riteshh@...ux.ibm.com>
Reviewed-by: Jan Kara <jack@...e.cz>
---
 fs/ext4/ioctl.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index f81acbbb1b12e..2162db0c747d2 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -754,11 +754,6 @@ static int ext4_ioctl_get_es_cache(struct file *filp, unsigned long arg)
 	fieinfo.fi_extents_max = fiemap.fm_extent_count;
 	fieinfo.fi_extents_start = ufiemap->fm_extents;
 
-	if (fiemap.fm_extent_count != 0 &&
-	    !access_ok(fieinfo.fi_extents_start,
-		       fieinfo.fi_extents_max * sizeof(struct fiemap_extent)))
-		return -EFAULT;
-
 	error = ext4_get_es_cache(inode, &fieinfo, fiemap.fm_start,
 			fiemap.fm_length);
 	fiemap.fm_flags = fieinfo.fi_flags;
-- 
2.26.2