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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 05/14] fs: check FMODE_WRITE in __kernel_write
Date: Wed, 24 Jun 2020 18:13:26 +0200	[thread overview]
Message-ID: <20200624161335.1810359-6-hch@lst.de> (raw)
In-Reply-To: <20200624161335.1810359-1-hch@lst.de>

Add a WARN_ON_ONCE if the file isn't actually open for write.  This
matches the check done in vfs_write, but actually warn warns as a
kernel user calling write on a file not opened for writing is a pretty
obvious programming error.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/read_write.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/read_write.c b/fs/read_write.c
index 2c601d853ff3d8..8f9fc05990ae8b 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -505,6 +505,8 @@ ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t
 	const char __user *p;
 	ssize_t ret;
 
+	if (WARN_ON_ONCE(!(file->f_mode & FMODE_WRITE)))
+		return -EBADF;
 	if (!(file->f_mode & FMODE_CAN_WRITE))
 		return -EINVAL;
 
-- 
2.26.2


  parent reply	other threads:[~2020-06-24 16:16 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-24 16:13 clean up kernel_{read,write} & friends v5 Christoph Hellwig
2020-06-24 16:13 ` [PATCH 01/14] cachefiles: switch to kernel_write Christoph Hellwig
2020-06-24 16:13 ` [PATCH 02/14] autofs: " Christoph Hellwig
2020-06-24 16:13 ` [PATCH 03/14] bpfilter: " Christoph Hellwig
2020-06-24 16:13 ` [PATCH 04/14] fs: unexport __kernel_write Christoph Hellwig
2020-06-24 16:13 ` Christoph Hellwig [this message]
2020-06-24 16:13 ` [PATCH 06/14] fs: implement kernel_write using __kernel_write Christoph Hellwig
2020-06-24 16:13 ` [PATCH 07/14] fs: remove __vfs_write Christoph Hellwig
2020-06-24 16:13 ` [PATCH 08/14] fs: don't change the address limit for ->write_iter in __kernel_write Christoph Hellwig
2020-06-24 16:13 ` [PATCH 09/14] fs: add a __kernel_read helper Christoph Hellwig
2020-06-24 16:13 ` [PATCH 10/14] integrity/ima: switch to using __kernel_read Christoph Hellwig
2020-06-24 16:13 ` [PATCH 11/14] fs: implement kernel_read " Christoph Hellwig
2020-06-24 16:13 ` [PATCH 12/14] fs: remove __vfs_read Christoph Hellwig
2020-06-24 16:13 ` [PATCH 13/14] fs: implement default_file_splice_read using __kernel_read Christoph Hellwig
2020-07-01  9:19   ` [fs] 140402bab8: stress-ng.splice.ops_per_sec -100.0% regression kernel test robot
2020-07-01 12:13     ` Christoph Hellwig
2020-07-01 20:32       ` Linus Torvalds
2020-06-24 16:13 ` [PATCH 14/14] fs: don't change the address limit for ->read_iter in __kernel_read Christoph Hellwig
  -- strict thread matches above, loose matches on Subject: below --
2020-05-28  5:40 clean up kernel_{read,write} & friends v2 Christoph Hellwig
2020-05-28  5:40 ` [PATCH 05/14] fs: check FMODE_WRITE in __kernel_write Christoph Hellwig
2020-05-13  6:56 clean up kernel_{read,write} & friends v2 Christoph Hellwig
2020-05-13  6:56 ` [PATCH 05/14] fs: check FMODE_WRITE in __kernel_write Christoph Hellwig

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