From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx49qrhnTegmyOI4lO9WcDa/WwDC0UBUeaKtmYwngOGslBSZ8Smnq6s5ZtZGR9vTqYZqs3tF9 ARC-Seal: i=1; a=rsa-sha256; t=1523021947; cv=none; d=google.com; s=arc-20160816; b=iBv0qeuUYVGf3SFoOCwJlOidege9IoLnHHoQpmF4DHm8LotgBTXNUt0zf0kus5EB7b ppVlafIPPCtuX0XPHmY9oXBK4qnjpFLdYkjFrPqxe408ANKCxNMEsmey9n2Gl6ej1NNo d8/cC+l8xUQpikGNIIo4UMbD1+77tGERKOtKHuYRhBBAnQCceUxR7dq+jbKiCJrnz5ZU I3T4L5AI8mqMsvpeWhPd0VcXkmph7XspIR+Sm7X6QcY5l5o9lWgsRaLcF0byaNmxai3W aXecLVfQXlxHKX9HyWBFZWMq5/QRjqxIiTT+0IlCF6JmqP/+iJR1CVG19dZs1BHIGI3e rObQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=Bcu74ZH/oLIye/HRxcXyo+yvnTbUHb2l7UQYe5fUjDo=; b=keeOMdiFkOxtycMht5fY83goHl4OaIwZZhwxbaSHvJBTsS5Zd/NDfeg65vpjpSRcvW Jsmv/XkxncysrTZCh1kdmuuejlq0RqsnX/J6yxNWPEzHo8zJAMmZmO3hVAHH0gyK+rX4 WUrW5JtorKoqXHjxkrJcDGzKo6HbOGkPo9GhkfIL++T9T4OAhxFXEiHmaAMjObXmUNzU kYTBcUIl0cU7kNul51swWc+BgDfAcGKYl9lrpg9OgSzxjZctXQoRjMrE7ldWhE80358Y SOYjAYK0pamCpHQz4GydJV+n4shTfftY81b42tYacqw9LVwt8GWLnhVThUTHbvWek5O6 /NWw== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Brad Spengler , Kees Cook Subject: [PATCH 4.14 43/67] /dev/mem: Avoid overwriting "err" in read_mem() Date: Fri, 6 Apr 2018 15:24:13 +0200 Message-Id: <20180406084347.133202378@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180406084341.225558262@linuxfoundation.org> References: <20180406084341.225558262@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1597004262523663859?= X-GMAIL-MSGID: =?utf-8?q?1597004262523663859?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.14-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);