From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:37046 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756594AbeDFNmg (ORCPT ); Fri, 6 Apr 2018 09:42:36 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Brad Spengler , Kees Cook Subject: [PATCH 4.15 46/72] /dev/mem: Avoid overwriting "err" in read_mem() Date: Fri, 6 Apr 2018 15:24:21 +0200 Message-Id: <20180406084352.803320780@linuxfoundation.org> In-Reply-To: <20180406084349.367583460@linuxfoundation.org> References: <20180406084349.367583460@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kees Cook commit b5b38200ebe54879a7264cb6f33821f61c586a7e upstream. Successes in probe_kernel_read() would mask failures in copy_to_user() during read_mem(). Reported-by: Brad Spengler Fixes: 22ec1a2aea73 ("/dev/mem: Add bounce buffer for copy-out") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman --- drivers/char/mem.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -137,7 +137,7 @@ static ssize_t read_mem(struct file *fil while (count > 0) { unsigned long remaining; - int allowed; + int allowed, probe; sz = size_inside_page(p, count); @@ -160,9 +160,9 @@ static ssize_t read_mem(struct file *fil if (!ptr) goto failed; - err = probe_kernel_read(bounce, ptr, sz); + probe = probe_kernel_read(bounce, ptr, sz); unxlate_dev_mem_ptr(p, ptr); - if (err) + if (probe) goto failed; remaining = copy_to_user(buf, bounce, sz);