From patchwork Mon Dec 28 12:48:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 354797 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 80BF1C433E0 for ; Mon, 28 Dec 2020 14:44:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 59ECD208D5 for ; Mon, 28 Dec 2020 14:44:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2503201AbgL1OZ0 (ORCPT ); Mon, 28 Dec 2020 09:25:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:33334 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2503197AbgL1OZ0 (ORCPT ); Mon, 28 Dec 2020 09:25:26 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6C833229C5; Mon, 28 Dec 2020 14:24:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609165485; bh=AiQ5/sQNlZG7KPCDNVwAS1q8blgrB27JK5GC4mhyu84=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=t7qaYDyDACVpBMqjpHSzrjNw2Mvf23mlaOogFz5A5tOcw9LhaILIMnNRsIJCHdS5Q pW20UMK0j1zMELUdbpv7u1plZBflMrG2PKIpvTEwG7OtF08y1lw4gvKD3cJSMAAaxK G4tr0A8RCiONX9RmV9P1L1S6SpsgEXTLO1hdAP+Q= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jens Axboe , "Eric W. Biederman" , Casey Schaufler , Sasha Levin Subject: [PATCH 5.10 508/717] Smack: Handle io_uring kernel thread privileges Date: Mon, 28 Dec 2020 13:48:26 +0100 Message-Id: <20201228125045.299088799@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228125020.963311703@linuxfoundation.org> References: <20201228125020.963311703@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Casey Schaufler [ Upstream commit 942cb357ae7d9249088e3687ee6a00ed2745a0c7 ] Smack assumes that kernel threads are privileged for smackfs operations. This was necessary because the credential of the kernel thread was not related to a user operation. With io_uring the credential does reflect a user's rights and can be used. Suggested-by: Jens Axboe Acked-by: Jens Axboe Acked-by: Eric W. Biederman Signed-off-by: Casey Schaufler Signed-off-by: Sasha Levin --- security/smack/smack_access.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c index efe2406a39609..7eabb448acab4 100644 --- a/security/smack/smack_access.c +++ b/security/smack/smack_access.c @@ -688,9 +688,10 @@ bool smack_privileged_cred(int cap, const struct cred *cred) bool smack_privileged(int cap) { /* - * All kernel tasks are privileged + * Kernel threads may not have credentials we can use. + * The io_uring kernel threads do have reliable credentials. */ - if (unlikely(current->flags & PF_KTHREAD)) + if ((current->flags & (PF_KTHREAD | PF_IO_WORKER)) == PF_KTHREAD) return true; return smack_privileged_cred(cap, current_cred());