From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D7A05C43334 for ; Thu, 23 Jun 2022 18:10:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236330AbiFWSKP (ORCPT ); Thu, 23 Jun 2022 14:10:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48336 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233369AbiFWSGI (ORCPT ); Thu, 23 Jun 2022 14:06:08 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D93C860C48; Thu, 23 Jun 2022 10:18:12 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B3A77B824B9; Thu, 23 Jun 2022 17:18:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0FEEFC341C5; Thu, 23 Jun 2022 17:18:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1656004689; bh=fBU7IPs0E+Na+OQLrUJRsGKxqjI7vklE+yq1nJxbwYM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xEyeh9ibXQvE2OPI7LeDCB6hHjDttvRvouxk/1+VwGMem/1sFK/TcHNYN8jp7GngR 43OZdygok2RUgnA6SUzLz3cUEEEIBbZrgbB2FcpCSOOP6YCcVRosc/wq0hNzHFNn0E tR0i2y5Z3kvRPMzVq647wZAsp1wkdLc+q7ZGdlY8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Theodore Tso , Dominik Brodowski , "Jason A. Donenfeld" Subject: [PATCH 4.19 117/234] random: dont let 644 read-only sysctls be written to Date: Thu, 23 Jun 2022 18:43:04 +0200 Message-Id: <20220623164346.369104038@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220623164343.042598055@linuxfoundation.org> References: <20220623164343.042598055@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Jason A. Donenfeld" commit 77553cf8f44863b31da242cf24671d76ddb61597 upstream. We leave around these old sysctls for compatibility, and we keep them "writable" for compatibility, but even after writing, we should keep reporting the same value. This is consistent with how userspaces tend to use sysctl_random_write_wakeup_bits, writing to it, and then later reading from it and using the value. Cc: Theodore Ts'o Reviewed-by: Dominik Brodowski Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman --- drivers/char/random.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1662,6 +1662,13 @@ static int proc_do_uuid(struct ctl_table return proc_dostring(&fake_table, 0, buffer, lenp, ppos); } +/* The same as proc_dointvec, but writes don't change anything. */ +static int proc_do_rointvec(struct ctl_table *table, int write, void __user *buffer, + size_t *lenp, loff_t *ppos) +{ + return write ? 0 : proc_dointvec(table, 0, buffer, lenp, ppos); +} + extern struct ctl_table random_table[]; struct ctl_table random_table[] = { { @@ -1683,14 +1690,14 @@ struct ctl_table random_table[] = { .data = &sysctl_random_write_wakeup_bits, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = proc_do_rointvec, }, { .procname = "urandom_min_reseed_secs", .data = &sysctl_random_min_urandom_seed, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = proc_do_rointvec, }, { .procname = "boot_id",