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 7344DC433EF for ; Thu, 23 Jun 2022 17:33:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231847AbiFWRdV (ORCPT ); Thu, 23 Jun 2022 13:33:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234471AbiFWRcq (ORCPT ); Thu, 23 Jun 2022 13:32:46 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3FC0C86AC3; Thu, 23 Jun 2022 10:05:29 -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 6FFB3B82499; Thu, 23 Jun 2022 17:05:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF622C3411B; Thu, 23 Jun 2022 17:05:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1656003927; bh=fBU7IPs0E+Na+OQLrUJRsGKxqjI7vklE+yq1nJxbwYM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GZBGrqn/QVyUNQx5MsukRs4s+7Yy3mhskyRqtgVPjL9dp4xtVJguAS5kr5E5zh/KZ /kbWLBlp0hXQdq3Z/PvTLXNLZLwFFMOJfrL2XV4zFHTl5++bFZRo1WDJ+YZICxmYuo 7quCCAyRNuf+5jHEJuv3wUDFGBNeA3RdivkQ33hQ= 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 4.14 130/237] random: dont let 644 read-only sysctls be written to Date: Thu, 23 Jun 2022 18:42:44 +0200 Message-Id: <20220623164346.894479540@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220623164343.132308638@linuxfoundation.org> References: <20220623164343.132308638@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: stable@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",