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=-10.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, T_DKIMWL_WL_MED,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 8C5B9C3279B for ; Fri, 6 Jul 2018 15:17:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3A82523EA9 for ; Fri, 6 Jul 2018 15:17:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="jypCqXAz" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3A82523EA9 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933045AbeGFPQ5 (ORCPT ); Fri, 6 Jul 2018 11:16:57 -0400 Received: from mail-yw0-f202.google.com ([209.85.161.202]:45584 "EHLO mail-yw0-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753759AbeGFPQ4 (ORCPT ); Fri, 6 Jul 2018 11:16:56 -0400 Received: by mail-yw0-f202.google.com with SMTP id y126-v6so10189290ywe.12 for ; Fri, 06 Jul 2018 08:16:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:date:message-id:subject:from:to:cc; bh=MRaE8D/X/qaIGQSG+GECxYL3MgyJE3KC232lcqNYOtc=; b=jypCqXAzaocvxG9hwcwvfRfUW5IIel0WSV1jlshBeGm96DQzcCFEDvfcX99LIhjgg0 RBkD3tP0lIvP7nfOoWQmbJLe9FFvv8D4hEckHXR67MQEo9DZeDEa90YnhHqme9sWc9Ul ym/xBLKrUWZrEy0Umbj0iy95SY3CTtgvN/CCUuWyE+y6Ja6OpKdcSaNb9TJH+Z+Eq1P7 cN1UfRiO7N5PYGbVyDAkQ+dDjtRtws3Z6tB08zU46ZmqH4Y/AO6gvCvyvBFg7Ld2OM4G sbx1iUMchElDNzOe2FThd973aCKZj/T++HKCC0Rw0c1B5Lh6jx1zE9IUzlPeyYcIvkGa PkBw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:message-id:subject:from:to:cc; bh=MRaE8D/X/qaIGQSG+GECxYL3MgyJE3KC232lcqNYOtc=; b=XO7hahMC7aNYFyMlxUF65cNTlPnPq3k5zEkwv6gcGE8I4r7ntbydXdxUAtlyxyHghf yBrgw37+P+Y/ER09zOHGcw+4+jgABrbkP3D0yEPQgfilFakS/5tJvM6ZWbQr020BQvcY BAnlp7drgIg5S4C4aRVb3DdA+2LnLT0zW2CcJ/NVYs8tzG79FC0QztUl+4E5eGUAkvJ/ GVQaWAZFhxqsop+vikvco7/I1seb7q6SL9QE8I4XvfVL11gVEBg3oXnQKqZJJU4C7iLr 15dYtX0UfdGTv9PdEAoK6kY7AWlEfkhNUw9YYO4dtOrgcO49DhrXcPW9BtPFmlhzGrVQ PuPg== X-Gm-Message-State: APt69E0W5gf6E0kP9dGLCAXLvDwK3BYIWXf8DJ0c2UsSHN26h5KI8YQF s7xXoddiVTi10Wl8weXNeOfs7RHwiA== X-Google-Smtp-Source: AAOMgpc+eX5BLEHCQOzzf+MuWoUIg2rGvLXPTESguHqYjdiFQCelsFgt/JrDBmSDS0RAj5GYmBcHYVr+yg== MIME-Version: 1.0 X-Received: by 2002:a25:9b02:: with SMTP id y2-v6mr3185004ybn.11.1530890215341; Fri, 06 Jul 2018 08:16:55 -0700 (PDT) Date: Fri, 6 Jul 2018 17:16:49 +0200 Message-Id: <20180706151649.31119-1-jannh@google.com> X-Mailer: git-send-email 2.18.0.399.gad0ab374a1-goog Subject: [PATCH] firewire: nosy: don't read packets bigger than requested From: Jann Horn To: Stefan Richter , jannh@google.com Cc: linux1394-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In general, accessing userspace memory beyond the length of the supplied buffer in VFS read/write handlers can lead to both kernel memory corruption (via kernel_read()/kernel_write(), which can e.g. be triggered via sys_splice()) and privilege escalation inside userspace. Fixes: 286468210d83 ("firewire: new driver: nosy - IEEE 1394 traffic sniffer") Signed-off-by: Jann Horn --- No CC stable because this device shouldn't be available to unprivileged code by default and should be pretty rare. drivers/firewire/nosy.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/firewire/nosy.c b/drivers/firewire/nosy.c index a128dd1126ae..732075fc312e 100644 --- a/drivers/firewire/nosy.c +++ b/drivers/firewire/nosy.c @@ -161,11 +161,12 @@ packet_buffer_get(struct client *client, char __user *data, size_t user_length) if (atomic_read(&buffer->size) == 0) return -ENODEV; - /* FIXME: Check length <= user_length. */ - end = buffer->data + buffer->capacity; length = buffer->head->length; + if (length > user_length) + return -EINVAL; + if (&buffer->head->data[length] < end) { if (copy_to_user(data, buffer->head->data, length)) return -EFAULT; -- 2.18.0.399.gad0ab374a1-goog