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 862ABC433EF for ; Fri, 27 May 2022 12:04:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345813AbiE0MEE (ORCPT ); Fri, 27 May 2022 08:04:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57540 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352733AbiE0Lzi (ORCPT ); Fri, 27 May 2022 07:55:38 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1097F14B67F; Fri, 27 May 2022 04:49:01 -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 5F6C0B824CA; Fri, 27 May 2022 11:49:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB40CC385A9; Fri, 27 May 2022 11:48:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1653652139; bh=112rpqfBHZG5Knz4Q5D4qmKKkDWxTkkyP+SwPAWWXkY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RTQ+9cjM+XQAd3Kgnv7RxPu6G5FdYtulZDil1QQvhYNlnYs8A/tzSQXDNTp3kbFgB Y76v2jtlTmS4qnkqwdYbNDCw3vrCE3GyIM/xnBR0VbzS8bo3tO/GoaYOZYtPUM03+w DHlo1P0bQAv4bJ3cZJquJNc4YCCYUXWww6wHF6qI= 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 5.10 103/163] random: dont let 644 read-only sysctls be written to Date: Fri, 27 May 2022 10:49:43 +0200 Message-Id: <20220527084842.344288009@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220527084828.156494029@linuxfoundation.org> References: <20220527084828.156494029@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 @@ -1669,6 +1669,13 @@ 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 *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[] = { { @@ -1690,14 +1697,14 @@ 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",