From patchwork Wed Nov 25 16:24:52 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marco Elver X-Patchwork-Id: 11931491 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=-21.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=ham 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 9CEE6C71155 for ; Wed, 25 Nov 2020 16:25:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 51B1D2067C for ; Wed, 25 Nov 2020 16:25:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="F46PSwOp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731176AbgKYQZd (ORCPT ); Wed, 25 Nov 2020 11:25:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58024 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731180AbgKYQZc (ORCPT ); Wed, 25 Nov 2020 11:25:32 -0500 Received: from mail-qv1-xf49.google.com (mail-qv1-xf49.google.com [IPv6:2607:f8b0:4864:20::f49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 85FB9C061A51 for ; Wed, 25 Nov 2020 08:25:32 -0800 (PST) Received: by mail-qv1-xf49.google.com with SMTP id o16so2932446qvq.4 for ; Wed, 25 Nov 2020 08:25:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:message-id:mime-version:subject:from:to:cc; bh=kvx4ypKzsvTsNRkpKLbQXMSUgG7LqQJ459IESbUi2Pg=; b=F46PSwOpar3alalr8VdSc32WF8ZCnTqLw516KRpy+NOz0v2dRAp7gABdRgRy8vjc3h 7j9Nl1u6k9E/YCFDbyixPa0kxt5kmVdTEoYgRoNMuG8nh9WznyRGlXREt4+7KWt3t5+D 0mbpMOJCD+b0a0SrqcmW9u+MwFadoYmAehlXbW3jlik8aKZyrBKtL0hIBc1pcmkV9ckJ /urKKWEifAqDent70J4kJ4VQMtzZikcxO6WeycD/z/Cx5HgOuW3K23BXrunnfAwuVTj0 6XJhNI0VCNdf8bjVH+fXHX4pma9+ByASbgUTb42vKQ38Hn/oC/oiOeTpyouKnSfEPx6l YCMw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:message-id:mime-version:subject:from :to:cc; bh=kvx4ypKzsvTsNRkpKLbQXMSUgG7LqQJ459IESbUi2Pg=; b=AraZhARPJMuWx8bgqoiNt8g4uf3XlNB7xaMKIzsJAc2EYondYBMVNg8FVKLN/uIJ7+ a/mXbqvD/slPIb5PDCJdN3aVkZAfYM7hj4RisgLsHCXDhYPQmIKhzxHvJk49tPtFN1WW P3GvRpmRAcD2ByRc56urVTdIDiRB0TuH65p5NsWZA3oRmveOBMLUItwqGLyPwRKek/Oh Zu3u4u+TkdHwAD8gLRoLzIyRiyuYWtATE3iBo5TWYPQBSrkPEa/B32LU2BP6l6ERD0Fm gaaTrivz0pwR90WvSshLqtaY6stZX+fNfOIxiH3pbf7tAJCH+vF7u0cWHfkFZQPjnC0J 1YHw== X-Gm-Message-State: AOAM5335aGVso1r+XsqjmEBy5Pn390wnRmt+q8vCQkadG3L9NjjthOFq v440EpLkspzdnYqG4GX177UBn6pysg== X-Google-Smtp-Source: ABdhPJxvAj93w4pXw/f7H9LNJVuezNeFs/6sMy3/w1UTClQjk6mqW2m/0/aBkAlKr80YHn7hMsyar/P5Vg== Sender: "elver via sendgmr" X-Received: from elver.muc.corp.google.com ([2a00:79e0:15:13:f693:9fff:fef4:2449]) (user=elver job=sendgmr) by 2002:a0c:9e6b:: with SMTP id z43mr4415819qve.6.1606321531530; Wed, 25 Nov 2020 08:25:31 -0800 (PST) Date: Wed, 25 Nov 2020 17:24:52 +0100 Message-Id: <20201125162455.1690502-1-elver@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.29.2.454.gaff20da3a2-goog Subject: [PATCH v6 0/3] net, mac80211, kernel: enable KCOV remote coverage collection for 802.11 frame handling From: Marco Elver To: elver@google.com, davem@davemloft.net, kuba@kernel.org, johannes@sipsolutions.net Cc: akpm@linux-foundation.org, a.nogikh@gmail.com, edumazet@google.com, andreyknvl@google.com, dvyukov@google.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, idosch@idosch.org, fw@strlen.de, willemb@google.com Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Aleksandr Nogikh This patch series enables remote KCOV coverage collection during 802.11 frames processing. These changes make it possible to perform coverage-guided fuzzing in search of remotely triggerable bugs. Normally, KCOV collects coverage information for the code that is executed inside the system call context. It is easy to identify where that coverage should go and whether it should be collected at all by looking at the current process. If KCOV was enabled on that process, coverage will be stored in a buffer specific to that process. Howerever, it is not always enough as handling can happen elsewhere (e.g. in separate kernel threads). When it is impossible to infer KCOV-related info just by looking at the currently running process, one needs to manually pass some information to the code that should be instrumented. The information takes the form of 64 bit integers (KCOV remote handles). Zero is the special value that corresponds to an empty handle. More details on KCOV and remote coverage collection can be found in Documentation/dev-tools/kcov.rst. The series consists of three patches: 1. Apply a minor fix to kcov_common_handle() so that it returns a valid handle (zero) when called in an interrupt context. 2. Take the remote handle from KCOV and attach it to newly allocated SKBs. If the allocation happens inside a system call context, the SKB will be tied to the process that issued the syscall (if that process is interested in remote coverage collection). 3. Annotate the code that processes incoming 802.11 frames with kcov_remote_start()/kcov_remote_stop(). v6: * Revert usage of skb extensions due to potential memory leak. Patch 2/3 is now idential to that in v2. * Patches 1/3 and 3/3 are otherwise identical to v5. v5: https://lore.kernel.org/linux-wireless/20201029173620.2121359-1-aleksandrnogikh@gmail.com/ * Collecting remote coverate at ieee80211_rx_list() instead of ieee80211_rx() v4: https://lkml.kernel.org/r/20201028182018.1780842-1-aleksandrnogikh@gmail.com * CONFIG_SKB_EXTENSIONS is now automatically selected by CONFIG_KCOV. * Elaborated on a minor optimization in skb_set_kcov_handle(). v3: https://lkml.kernel.org/r/20201026150851.528148-1-aleksandrnogikh@gmail.com * kcov_handle is now stored in skb extensions instead of sk_buff itself. * Updated the cover letter. v2: https://lkml.kernel.org/r/20201009170202.103512-1-a.nogikh@gmail.com * Moved KCOV annotations from ieee80211_tasklet_handler to ieee80211_rx. * Updated kcov_common_handle() to return 0 if it is called in interrupt context. v1: https://lkml.kernel.org/r/20201007101726.3149375-1-a.nogikh@gmail.com Aleksandr Nogikh (3): kernel: make kcov_common_handle consider the current context net: store KCOV remote handle in sk_buff mac80211: add KCOV remote annotations to incoming frame processing include/linux/skbuff.h | 21 +++++++++++++++++++++ kernel/kcov.c | 2 ++ net/core/skbuff.c | 1 + net/mac80211/iface.c | 2 ++ net/mac80211/rx.c | 16 +++++++++------- 5 files changed, 35 insertions(+), 7 deletions(-)