linux-kernel - [PATCH v2] vc_screen: modify vcs_size() handling in vcs

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Message-Id: <1677529301-19530-1-git-send-email-george.kennedy@oracle.com>
Date:   Mon, 27 Feb 2023 15:21:41 -0500
From:   George Kennedy <george.kennedy@...cle.com>
To:     jirislaby@...nel.org, gregkh@...uxfoundation.org,
        torvalds@...ux-foundation.org
Cc:     george.kennedy@...cle.com, sfr@...b.auug.org.au,
        akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
        linux-serial@...r.kernel.org, linux@...ssschuh.net,
        regressions@...ts.linux.dev
Subject: [PATCH v2] vc_screen: modify vcs_size() handling in vcs_read()

Restore the vcs_size() handling in vcs_read() to what
it had been in previous version.

Fixes: 226fae124b2d ("vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF")
Suggested-by: Jiri Slaby <jirislaby@...nel.org>
Signed-off-by: George Kennedy <george.kennedy@...cle.com>
---
v2: added Fixes

 drivers/tty/vt/vc_screen.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/tty/vt/vc_screen.c b/drivers/tty/vt/vc_screen.c
index f566eb1839dc..c0a2273bb998 100644
--- a/drivers/tty/vt/vc_screen.c
+++ b/drivers/tty/vt/vc_screen.c
@@ -414,10 +414,8 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 		 */
 		size = vcs_size(vc, attr, uni_mode);
 		if (size < 0) {
-			if (read)
-				break;
 			ret = size;
-			goto unlock_out;
+			break;
 		}
 		if (pos >= size)
 			break;
-- 
2.31.1