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=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 654E4C433DF for ; Wed, 22 Jul 2020 16:07:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4278320717 for ; Wed, 22 Jul 2020 16:07:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="a8k1mfHu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728186AbgGVQHZ (ORCPT ); Wed, 22 Jul 2020 12:07:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38880 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726406AbgGVQHX (ORCPT ); Wed, 22 Jul 2020 12:07:23 -0400 Received: from mail-qk1-x742.google.com (mail-qk1-x742.google.com [IPv6:2607:f8b0:4864:20::742]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C3208C0619DC; Wed, 22 Jul 2020 09:07:23 -0700 (PDT) Received: by mail-qk1-x742.google.com with SMTP id x69so2508101qkb.1; Wed, 22 Jul 2020 09:07:23 -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=inXRPYgND6+0WE39IDvE6wldzJTBYfDxX/wQ/vOfPn0=; b=a8k1mfHuBtctSv/v34AEQtJKDDMJsmzgQiLNEMGt4v2xwXaP9+GEfP4S+dVZi9N5cm StZ5VmZHe2C9KFpm5eofHmXUSvhi240cLFMIKR7UoqZ+KwFyYOXEZdIAbWrh7WAmVu4o 7OcBxIEmwji96oE6vzBnqIvyyolTXj+IlHB/WVPIq0FWjRTz4zKz9GVi7/uWcYDDWFeu OqcdP+yyS4UEjao+xsT+J2XbAySKFfuFsUPmlbi8SM84zy/p3CExBuMfJQ6sk2CPMnnJ cKxPqrDOJnOgIQyJ2xBQ9c6B2wlAss8VNk//84EIuIgbdRYnnERBUNuz5E6J9LoAwTOu bSAg== 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=inXRPYgND6+0WE39IDvE6wldzJTBYfDxX/wQ/vOfPn0=; b=UK412WiPGhcjb9w0Hfdi6XiKbWrQF7dfnC30EAAxmN7PZIQ3M9oSNB3r4hRDq3s4/L QTSDxHX3RWLEAc0a/eOwjYDn7iCdRLo0LEv65lCKWJXno0jX7aVH/439IxNuuD0pfrFq polnLqLlIBaX86JawcnxE6p2KRAnROYlWEPXeWKQJHP/FTEOkIu3lHxxhInbTw6+rJW2 0PCesmYsax1uXdIfyGsqHl9+joMLzRFYVDaxKthsKkqYA3+GQhvZp+HG6cO8dRvZB5Fp 9g33QFqGEB0aYWasLBcJGoVgS6kUuRkgne0fpnStWuMTTT2e2he7R8EZuybxGJDFS4NG xUGw== X-Gm-Message-State: AOAM5326rxDnpKxnVUpmQ2zlX5zyPI3bJ/j17/5R4ufBNuJz+P2XjAHF gtQYpEzlixq4gpvldTDQDuAXowU3nw== X-Google-Smtp-Source: ABdhPJx8zadp5hybrNbT1YGP6AF/F1kHC13kJf+YtmdUCtFIfFdTeqlM39WpgDmRgaDFzLlCZ3LU0A== X-Received: by 2002:a37:8302:: with SMTP id f2mr644452qkd.271.1595434041414; Wed, 22 Jul 2020 09:07:21 -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 f54sm76376qte.76.2020.07.22.09.07.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Jul 2020 09:07:20 -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: Prevent out-of-bounds read in ax25_sendmsg() Date: Wed, 22 Jul 2020 12:05:12 -0400 Message-Id: <20200722160512.370802-1-yepeilin.cs@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Checks on `addr_len` and `usax->sax25_ndigis` are insufficient. ax25_sendmsg() can go out of bounds when `usax->sax25_ndigis` equals to 7 or 8. Fix it. It is safe to remove `usax->sax25_ndigis > AX25_MAX_DIGIS`, since `addr_len` is guaranteed to be less than or equal to `sizeof(struct full_sockaddr_ax25)` Signed-off-by: Peilin Ye --- net/ax25/af_ax25.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c index ef5bf116157a..0862fe49d434 100644 --- a/net/ax25/af_ax25.c +++ b/net/ax25/af_ax25.c @@ -1509,7 +1509,8 @@ static int ax25_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) struct full_sockaddr_ax25 *fsa = (struct full_sockaddr_ax25 *)usax; /* Valid number of digipeaters ? */ - if (usax->sax25_ndigis < 1 || usax->sax25_ndigis > AX25_MAX_DIGIS) { + if (usax->sax25_ndigis < 1 || addr_len < sizeof(struct sockaddr_ax25) + + sizeof(ax25_address) * usax->sax25_ndigis) { err = -EINVAL; goto out; } -- 2.25.1