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From: Christoph Hellwig <hch@lst.de>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-security-module@vger.kernel.org
Subject: [PATCH 09/11] fs: implement kernel_read using __kernel_read
Date: Fri,  8 May 2020 11:22:20 +0200	[thread overview]
Message-ID: <20200508092222.2097-10-hch@lst.de> (raw)
In-Reply-To: <20200508092222.2097-1-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 93f5724b4837d..0ffbed5fd8136 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	other threads:[~2020-05-08  9:22 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-08  9:22 clean up kernel_{read,write} & friends Christoph Hellwig
2020-05-08  9:22 ` [PATCH 01/11] fs: call file_{start,end}_write from __kernel_write Christoph Hellwig
2020-05-08  9:22 ` [PATCH 02/11] fs: check FMODE_WRITE in __kernel_write Christoph Hellwig
2020-05-08  9:22 ` [PATCH 03/11] fs: remove the call_{read,write}_iter functions Christoph Hellwig
2020-05-08  9:22 ` [PATCH 04/11] fs: implement kernel_write using __kernel_write Christoph Hellwig
2020-05-08  9:22 ` [PATCH 05/11] fs: remove __vfs_write Christoph Hellwig
2020-05-08  9:22 ` [PATCH 06/11] fs: don't change the address limit for ->write_iter in __kernel_write Christoph Hellwig
2020-05-08  9:22 ` [PATCH 07/11] fs: add a __kernel_read helper Christoph Hellwig
2020-05-08  9:22 ` [PATCH 08/11] integrity/ima: switch to using __kernel_read Christoph Hellwig
2020-05-08  9:22 ` Christoph Hellwig [this message]
2020-05-08  9:22 ` [PATCH 10/11] fs: remove __vfs_read Christoph Hellwig
2020-05-08 15:45   ` Ira Weiny
2020-05-08 15:46     ` Christoph Hellwig
2020-05-08  9:22 ` [PATCH 11/11] fs: don't change the address limit for ->read_iter in __kernel_read Christoph Hellwig

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