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 D91DCCCA479 for ; Mon, 20 Jun 2022 13:50:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241878AbiFTNuL (ORCPT ); Mon, 20 Jun 2022 09:50:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56020 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348180AbiFTNr6 (ORCPT ); Mon, 20 Jun 2022 09:47:58 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 10A722ED6A; Mon, 20 Jun 2022 06:17:40 -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 31AE7B80E7D; Mon, 20 Jun 2022 13:16:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 852B2C3411C; Mon, 20 Jun 2022 13:16:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655730978; bh=tgP0RprB/ziOwGFh2YoA80OFebgvpaanFA8mfj0LnTo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KknvPXb/U0HCEFNU+svlcNY1oJ88j8VJ+VwrTiRbaJobG56zps7gjs8taChW3pOaA sYoFfmQsXHXXGx/YTXSO7OJ/4raajpByOs1X2J722uYtF8xp3z5XAxJLhKazo2/d5r WnksOWk7OOa7rOAXEtpNFk/VCQWbX2LI3udpI8Rk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dominik Brodowski , "Jason A. Donenfeld" Subject: [PATCH 5.4 108/240] random: cleanup UUID handling Date: Mon, 20 Jun 2022 14:50:09 +0200 Message-Id: <20220620124742.144898647@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220620124737.799371052@linuxfoundation.org> References: <20220620124737.799371052@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 64276a9939ff414f2f0db38036cf4e1a0a703394 upstream. Rather than hard coding various lengths, we can use the right constants. Strings should be `char *` while buffers should be `u8 *`. Rather than have a nonsensical and unused maxlength, just remove it. Finally, use snprintf instead of sprintf, just out of good hygiene. As well, remove the old comment about returning a binary UUID via the binary sysctl syscall. That syscall was removed from the kernel in 5.5, and actually, the "uuid_strategy" function and related infrastructure for even serving it via the binary sysctl syscall was removed with 894d2491153a ("sysctl drivers: Remove dead binary sysctl support") back in 2.6.33. Reviewed-by: Dominik Brodowski Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman --- drivers/char/random.c | 29 +++++++++++++---------------- 1 file changed, 13 insertions(+), 16 deletions(-) --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1656,22 +1656,25 @@ const struct file_operations urandom_fop static int sysctl_random_min_urandom_seed = 60; static int sysctl_random_write_wakeup_bits = POOL_MIN_BITS; static int sysctl_poolsize = POOL_BITS; -static char sysctl_bootid[16]; +static u8 sysctl_bootid[UUID_SIZE]; /* * This function is used to return both the bootid UUID, and random - * UUID. The difference is in whether table->data is NULL; if it is, + * UUID. The difference is in whether table->data is NULL; if it is, * then a new UUID is generated and returned to the user. - * - * If the user accesses this via the proc interface, the UUID will be - * returned as an ASCII string in the standard UUID format; if via the - * sysctl system call, as 16 bytes of binary data. */ static int proc_do_uuid(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { - struct ctl_table fake_table; - unsigned char buf[64], tmp_uuid[16], *uuid; + u8 tmp_uuid[UUID_SIZE], *uuid; + char uuid_string[UUID_STRING_LEN + 1]; + struct ctl_table fake_table = { + .data = uuid_string, + .maxlen = UUID_STRING_LEN + }; + + if (write) + return -EPERM; uuid = table->data; if (!uuid) { @@ -1686,12 +1689,8 @@ static int proc_do_uuid(struct ctl_table spin_unlock(&bootid_spinlock); } - sprintf(buf, "%pU", uuid); - - fake_table.data = buf; - fake_table.maxlen = sizeof(buf); - - return proc_dostring(&fake_table, write, buffer, lenp, ppos); + snprintf(uuid_string, sizeof(uuid_string), "%pU", uuid); + return proc_dostring(&fake_table, 0, buffer, lenp, ppos); } extern struct ctl_table random_table[]; @@ -1727,13 +1726,11 @@ struct ctl_table random_table[] = { { .procname = "boot_id", .data = &sysctl_bootid, - .maxlen = 16, .mode = 0444, .proc_handler = proc_do_uuid, }, { .procname = "uuid", - .maxlen = 16, .mode = 0444, .proc_handler = proc_do_uuid, },