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From: Christoph Hellwig <hch@lst.de>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Ian Kent <raven@themaw.net>, David Howells <dhowells@redhat.com>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	netfilter-devel@vger.kernel.org
Subject: [PATCH 12/14] fs: implement kernel_read using __kernel_read
Date: Thu, 28 May 2020 07:40:41 +0200
Message-ID: <20200528054043.621510-13-hch@lst.de> (raw)
In-Reply-To: <20200528054043.621510-1-hch@lst.de>

Consolidate the two in-kernel read helpers to make upcoming changes
easier.  The only difference are the missing call to rw_verify_area
in kernel_read, and an access_ok check that doesn't make sense for
kernel buffers to start with.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/read_write.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index bd12af8a895c8..4e19152a7efe0 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -453,15 +453,12 @@ ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
 
 ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
 {
-	mm_segment_t old_fs;
-	ssize_t result;
+	ssize_t ret;
 
-	old_fs = get_fs();
-	set_fs(KERNEL_DS);
-	/* The cast to a user pointer is valid due to the set_fs() */
-	result = vfs_read(file, (void __user *)buf, count, pos);
-	set_fs(old_fs);
-	return result;
+	ret = rw_verify_area(READ, file, pos, count);
+	if (ret)
+		return ret;
+	return __kernel_read(file, buf, count, pos);
 }
 EXPORT_SYMBOL(kernel_read);
 
-- 
2.26.2


  parent reply index

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-28  5:40 clean up kernel_{read,write} & friends v2 Christoph Hellwig
2020-05-28  5:40 ` [PATCH 01/14] cachefiles: switch to kernel_write Christoph Hellwig
2020-05-28  5:40 ` [PATCH 02/14] autofs: " Christoph Hellwig
2020-05-28  5:40 ` [PATCH 03/14] bpfilter: " Christoph Hellwig
2020-05-28  5:40 ` [PATCH 04/14] fs: unexport __kernel_write Christoph Hellwig
2020-05-28  5:40 ` [PATCH 05/14] fs: check FMODE_WRITE in __kernel_write Christoph Hellwig
2020-05-28  5:40 ` [PATCH 06/14] fs: remove the call_{read,write}_iter functions Christoph Hellwig
2020-05-28 18:56   ` Al Viro
2020-05-29  5:51     ` Christoph Hellwig
2020-05-28  5:40 ` [PATCH 07/14] fs: implement kernel_write using __kernel_write Christoph Hellwig
2020-05-28  5:40 ` [PATCH 08/14] fs: remove __vfs_write Christoph Hellwig
2020-05-28  5:40 ` [PATCH 09/14] fs: don't change the address limit for ->write_iter in __kernel_write Christoph Hellwig
2020-05-28 18:43   ` Linus Torvalds
2020-05-29 12:32     ` Christoph Hellwig
2020-05-31 23:59       ` Logan Gunthorpe
2020-05-28 19:00   ` Al Viro
2020-05-29  5:57     ` Christoph Hellwig
2020-05-29 13:37       ` Christoph Hellwig
2020-05-28  5:40 ` [PATCH 10/14] fs: add a __kernel_read helper Christoph Hellwig
2020-05-28  5:40 ` [PATCH 11/14] integrity/ima: switch to using __kernel_read Christoph Hellwig
2020-05-28  5:40 ` Christoph Hellwig [this message]
2020-05-28  5:40 ` [PATCH 13/14] fs: remove __vfs_read Christoph Hellwig
2020-05-28  5:40 ` [PATCH 14/14] fs: don't change the address limit for ->read_iter in __kernel_read Christoph Hellwig
2020-05-28 19:03   ` Al Viro
2020-05-28 18:51 ` clean up kernel_{read,write} & friends v2 Linus Torvalds
2020-05-28 18:57   ` Sedat Dilek
2020-05-28 19:22   ` Joe Perches
2020-05-28 19:33     ` Al Viro
2020-05-28 19:44       ` Matthew Wilcox
2020-05-28 20:06         ` Al Viro
2020-05-28 20:14           ` Deucher, Alexander
2020-05-28 20:18         ` Joe Perches
2020-05-28 20:29       ` Dave Airlie
2020-05-28 21:03     ` Joe Perches
2020-05-28 20:17 ` David Howells
2020-05-28 21:20   ` Casey Schaufler
2020-05-29 13:08     ` David Laight
2020-05-29 19:19       ` Linus Torvalds
2020-05-29 22:02         ` Casey Schaufler
2020-05-29 23:12         ` [PATCH] checkpatch/coding-style: Allow 100 column lines Joe Perches
2020-05-30 22:14           ` Andreas Dilger
2020-05-30 23:15             ` Joe Perches
2020-06-05  6:36         ` clean up kernel_{read,write} & friends v2 Philippe Mathieu-Daudé
2020-06-05 15:00           ` Nicolas Pitre
  -- strict thread matches above, loose matches on Subject: below --
2020-05-13  6:56 Christoph Hellwig
2020-05-13  6:56 ` [PATCH 12/14] fs: implement kernel_read using __kernel_read Christoph Hellwig

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