linux-kernel - [PATCH 06/20] n_hdlc_tty_read(): remove pointless access

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Message-Id: <20200509234557.1124086-6-viro@ZenIV.linux.org.uk>
Date:   Sun, 10 May 2020 00:45:43 +0100
From:   Al Viro <viro@...IV.linux.org.uk>
To:     linux-kernel@...r.kernel.org
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-fsdevel@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH 06/20] n_hdlc_tty_read(): remove pointless access_ok()

From: Al Viro <viro@...iv.linux.org.uk>

only copy_to_user() is done to the address in question

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 drivers/tty/n_hdlc.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c
index 991f49ee4026..b09eac4b6d64 100644
--- a/drivers/tty/n_hdlc.c
+++ b/drivers/tty/n_hdlc.c
@@ -423,13 +423,6 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file,
 	struct n_hdlc_buf *rbuf;
 	DECLARE_WAITQUEUE(wait, current);
 
-	/* verify user access to buffer */
-	if (!access_ok(buf, nr)) {
-		pr_warn("%s(%d) %s() can't verify user buffer\n",
-				__FILE__, __LINE__, __func__);
-		return -EFAULT;
-	}
-
 	add_wait_queue(&tty->read_wait, &wait);
 
 	for (;;) {
-- 
2.11.0