From patchwork Thu Sep 27 19:17:20 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Schaufler, Casey" X-Patchwork-Id: 10618491 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 47622112B for ; Thu, 27 Sep 2018 19:17:37 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 364312B582 for ; Thu, 27 Sep 2018 19:17:37 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 28D6D2B5E6; Thu, 27 Sep 2018 19:17:37 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 5EC012B582 for ; Thu, 27 Sep 2018 19:17:35 +0000 (UTC) Received: (qmail 32605 invoked by uid 550); 27 Sep 2018 19:17:34 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 32573 invoked from network); 27 Sep 2018 19:17:33 -0000 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,311,1534834800"; d="scan'208";a="90082086" From: Casey Schaufler To: kernel-hardening@lists.openwall.com, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov, casey.schaufler@intel.com, dave.hansen@intel.com, deneen.t.dock@intel.com, kristen@linux.intel.com, arjan@linux.intel.com Subject: [PATCH 6/5] capability: Repair sidechannel test in ptrace Date: Thu, 27 Sep 2018 12:17:20 -0700 Message-Id: <20180927191720.9480-1-casey.schaufler@intel.com> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180824224117.3356-1-casey.schaufler@intel.com> References: <20180824224117.3356-1-casey.schaufler@intel.com> X-Virus-Scanned: ClamAV using ClamSMTP From: Casey Schaufler The PTRACE_MODE_SCHED check erroniously returns 0 in all cases. It should be returning -EPERM. This fixes the logic to correct that error. Signed-off-by: Casey Schaufler Reviewed-by: Jann Horn --- security/commoncap.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/security/commoncap.c b/security/commoncap.c index e77457110d05..70a7e3d19c16 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -152,9 +152,8 @@ int cap_ptrace_access_check(struct task_struct *child, unsigned int mode) if (cred->user_ns == child_cred->user_ns && cap_issubset(child_cred->cap_permitted, *caller_caps)) goto out; - if (mode & PTRACE_MODE_SCHED) - goto out; - if (ns_capable(child_cred->user_ns, CAP_SYS_PTRACE)) + if (!(mode & PTRACE_MODE_SCHED) && + ns_capable(child_cred->user_ns, CAP_SYS_PTRACE)) goto out; ret = -EPERM; out: