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 X-Spam-Level: X-Spam-Status: No, score=-13.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 22CEDC433DF for ; Wed, 22 Jul 2020 15:20:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ED8012071A for ; Wed, 22 Jul 2020 15:20:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="FZ8HekGe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732799AbgGVPUR (ORCPT ); Wed, 22 Jul 2020 11:20:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59712 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728046AbgGVPUR (ORCPT ); Wed, 22 Jul 2020 11:20:17 -0400 Received: from mail-qv1-xf43.google.com (mail-qv1-xf43.google.com [IPv6:2607:f8b0:4864:20::f43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4FD13C0619DC; Wed, 22 Jul 2020 08:20:17 -0700 (PDT) Received: by mail-qv1-xf43.google.com with SMTP id di5so1155679qvb.11; Wed, 22 Jul 2020 08:20:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=mC+9VCisrQOLG6kTWdRwYqg9YnRsNnWuSWD6BGUaBPU=; b=FZ8HekGeo5ShXhCW8K3Qz+diyX/yNtoMBwYcfNlQOkYqwJMOBDgkjjnrXxMcFytvl0 EUX2omBZVUM4mZLAJv89P8Bsab6RM96iDKoWFBid86ut6Rknmzs9hd4FivGcc5tzWmQe WPpqaU6RcomIDNnm5zy7m/x16lXpOcKVuJ8icY/dPG9fNcMZwDbSClIimXXW4FeW0x/k sYD9XbJqXHFmkDNHbxUi39CWdyXfFfd2joCrE6kn+tBk1FIU6AqzTvCiRBhFHukdqTv/ A/2auoshCGbIidQlhZt5lalBFxNltjZZYOPyxB0qTqMD5DqmgL5eZl/75YGNCnWB3mq1 /gDg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=mC+9VCisrQOLG6kTWdRwYqg9YnRsNnWuSWD6BGUaBPU=; b=EpJUoU3ByiX0FpbuMhoow2vNygHAiYkh8DUefhVS65aKN+pxJrkSTl6p2Yzm67VN46 G9NCXk+D/j7/6LjZQbYolTFW6pN9nldmLQ63/Za6nmkVpWlb9T9DWHgnshgJmNdAbEwj Co1P1IZey/92VGygwhX0BIYtPFYxV+ooKUtstBIrKWQIQRNbe9P8uyJUQ8aNEbyQK0W7 0WD4MhoYjNSg2oqJT7TmPDYSoxKu6Vamn0qXSyxo3tL8FIf5PoA6ESmlyCXFpxM3J4AX /YYzSwfasBz8l8oe2yanmEIGOPvnIPxz/zlqVbHqWIRK5DDgGS3eBCDJ5YrRQANhxii+ VIaw== X-Gm-Message-State: AOAM531ePh71OXvi/pIJxzl5rr7fTuYcuEk6V4gHBMiZM14u+ei/FC0N 5WhaEmTmD3igUuuihK4RdA== X-Google-Smtp-Source: ABdhPJyQlAbWhv80O6xSt+eVr/q5xPqqgm6J3gKBuQeelHhV7/HpWfRDD0xY6q8tS7Z3mN/bUfbdRQ== X-Received: by 2002:ad4:4583:: with SMTP id x3mr454680qvu.133.1595431216569; Wed, 22 Jul 2020 08:20:16 -0700 (PDT) Received: from localhost.localdomain (c-76-119-149-155.hsd1.ma.comcast.net. [76.119.149.155]) by smtp.gmail.com with ESMTPSA id 16sm147427qkv.48.2020.07.22.08.20.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Jul 2020 08:20:16 -0700 (PDT) From: Peilin Ye To: Joerg Reuter , Ralf Baechle Cc: Peilin Ye , Greg Kroah-Hartman , syzkaller-bugs@googlegroups.com, linux-kernel-mentees@lists.linuxfoundation.org, "David S . Miller" , Jakub Kicinski , linux-hams@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [Linux-kernel-mentees] [PATCH net] AX.25: Fix out-of-bounds read in ax25_connect() Date: Wed, 22 Jul 2020 11:19:01 -0400 Message-Id: <20200722151901.350003-1-yepeilin.cs@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Checks on `addr_len` and `fsa->fsa_ax25.sax25_ndigis` are insufficient. ax25_connect() can go out of bounds when `fsa->fsa_ax25.sax25_ndigis` equals to 7 or 8. Fix it. This issue has been reported as a KMSAN uninit-value bug, because in such a case, ax25_connect() reaches into the uninitialized portion of the `struct sockaddr_storage` statically allocated in __sys_connect(). It is safe to remove `fsa->fsa_ax25.sax25_ndigis > AX25_MAX_DIGIS` because `addr_len` is guaranteed to be less than or equal to `sizeof(struct full_sockaddr_ax25)`. Reported-by: syzbot+c82752228ed975b0a623@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=55ef9d629f3b3d7d70b69558015b63b48d01af66 Signed-off-by: Peilin Ye --- net/ax25/af_ax25.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c index fd91cd34f25e..ef5bf116157a 100644 --- a/net/ax25/af_ax25.c +++ b/net/ax25/af_ax25.c @@ -1187,7 +1187,9 @@ static int __must_check ax25_connect(struct socket *sock, if (addr_len > sizeof(struct sockaddr_ax25) && fsa->fsa_ax25.sax25_ndigis != 0) { /* Valid number of digipeaters ? */ - if (fsa->fsa_ax25.sax25_ndigis < 1 || fsa->fsa_ax25.sax25_ndigis > AX25_MAX_DIGIS) { + if (fsa->fsa_ax25.sax25_ndigis < 1 || + addr_len < sizeof(struct sockaddr_ax25) + + sizeof(ax25_address) * fsa->fsa_ax25.sax25_ndigis) { err = -EINVAL; goto out_release; } -- 2.25.1