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=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 C4CC2C433ED for ; Thu, 22 Apr 2021 22:16:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 91B40608FE for ; Thu, 22 Apr 2021 22:16:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236896AbhDVWRe (ORCPT ); Thu, 22 Apr 2021 18:17:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55404 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232844AbhDVWRc (ORCPT ); Thu, 22 Apr 2021 18:17:32 -0400 Received: from mail-ed1-x532.google.com (mail-ed1-x532.google.com [IPv6:2a00:1450:4864:20::532]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3BA45C06174A for ; Thu, 22 Apr 2021 15:16:56 -0700 (PDT) Received: by mail-ed1-x532.google.com with SMTP id i3so29615944edt.1 for ; Thu, 22 Apr 2021 15:16:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=RKilX3qohNIwUEMirvtf+1d+omhXJdcQrgZYKoNJp6w=; b=MbN/2Yj5BE7OZau9swwA3wfBo9iuX8K3NNnJUbM3TEMYb7v53hoLjW2ohST69RmOGO l4S4Gws85sxhk2/C4jqCZ6YnUXilMrCQlHQbPPFw753ODKCxeeqykCnSvynu0Vq2dyud jOVfBzC+YPDShAwrxZ4QucLfQ2RZ4txuXKJ6ysBAOWgUBVClMEvXOMGEVcCDCHvwI5J8 NdPGFgWC7IPxtoQkESyY1N32pHp5fPLyX0pORBk/eZLOIWWJ3/qhLmS46Z3dAOSzF9Z1 Sr2Gx6U08SmDSuywgmbwmimPoS2kfnlAbWq4f2CMAJodBxRa8+PcNCPKZmeBOaAEp8FC VvSg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=RKilX3qohNIwUEMirvtf+1d+omhXJdcQrgZYKoNJp6w=; b=JUAsjtFRmOupMs+nDGfM1GTNCdQAMMBET1xrLpAqCq89gJlS3Dx5EhOinOmca6Ljxj Yb4ZIJPRFMENUsWN2TNRCJdNffxOtdZADhCbsJFN7TXCI+a9GkkK43U9Bena1J0CetU/ RxRYOj7B0cLQ9peo3yvlw8XZZCUiaWd8F9DDLgIWXuhILiOENddKdvTgXUxLdCbE9XVQ hyq55yRbpfQ4OqKTB2L+f7RNjWFOJJiMqRU/wFdUc07DQm1tdaeSF/54nmYBdkpg7gKQ PnDi5WE0ldGkewmKJt9gPy7uRBW9d8yGieU2prFX6+a74t87A8Q9NZvCbNIpobChTZrk QEyQ== X-Gm-Message-State: AOAM531kGB/yqJyfmbmjBZAm1eyonU1NPmufl2DfmKIYzbqu+RXfXpgT CAnwlZq0PtyGK3yYkghMFVv0Mre26nE5SNCj/cRhSF2y X-Google-Smtp-Source: ABdhPJzzsgrUWsj44xBsBid89gMWkiLM77UdN1e32qlJ8XhsR1DUjr9302lwxTx9XqQmniH9iEaUeWX5Htw6I0NYiVU= X-Received: by 2002:a50:ee0b:: with SMTP id g11mr790031eds.218.1619129814971; Thu, 22 Apr 2021 15:16:54 -0700 (PDT) MIME-Version: 1.0 References: <20210422221403.13617-1-ddiss@suse.de> In-Reply-To: <20210422221403.13617-1-ddiss@suse.de> From: ronnie sahlberg Date: Fri, 23 Apr 2021 08:16:43 +1000 Message-ID: Subject: Re: [PATCH] cifs: fix leak in cifs_smb3_do_mount() ctx To: David Disseldorp Cc: linux-cifs Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Acked-by me On Fri, Apr 23, 2021 at 8:14 AM David Disseldorp wrote: > > cifs_smb3_do_mount() calls smb3_fs_context_dup() and then > cifs_setup_volume_info(). The latter's subsequent smb3_parse_devname() > call overwrites the cifs_sb->ctx->UNC string already dup'ed by > smb3_fs_context_dup(), resulting in a leak. E.g. > > unreferenced object 0xffff888002980420 (size 32): > comm "mount", pid 160, jiffies 4294892541 (age 30.416s) > hex dump (first 32 bytes): > 5c 5c 31 39 32 2e 31 36 38 2e 31 37 34 2e 31 30 \\192.168.174.10 > 34 5c 72 61 70 69 64 6f 2d 73 68 61 72 65 00 00 4\rapido-share.. > backtrace: > [<00000000069e12f6>] kstrdup+0x28/0x50 > [<00000000b61f4032>] smb3_fs_context_dup+0x127/0x1d0 [cifs] > [<00000000c6e3e3bf>] cifs_smb3_do_mount+0x77/0x660 [cifs] > [<0000000063467a6b>] smb3_get_tree+0xdf/0x220 [cifs] > [<00000000716f731e>] vfs_get_tree+0x1b/0x90 > [<00000000491d3892>] path_mount+0x62a/0x910 > [<0000000046b2e774>] do_mount+0x50/0x70 > [<00000000ca7b64dd>] __x64_sys_mount+0x81/0xd0 > [<00000000b5122496>] do_syscall_64+0x33/0x40 > [<000000002dd397af>] entry_SYSCALL_64_after_hwframe+0x44/0xae > > This change is a bandaid until the cifs_setup_volume_info() TODO and > error handling issues are resolved. > > Signed-off-by: David Disseldorp > --- > fs/cifs/cifsfs.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c > index 5ddd20b62484..34c125798ad3 100644 > --- a/fs/cifs/cifsfs.c > +++ b/fs/cifs/cifsfs.c > @@ -834,6 +834,12 @@ cifs_smb3_do_mount(struct file_system_type *fs_type, > goto out; > } > > + /* cifs_setup_volume_info->smb3_parse_devname() redups UNC & prepath */ > + kfree(cifs_sb->ctx->UNC); > + cifs_sb->ctx->UNC = NULL; > + kfree(cifs_sb->ctx->prepath); > + cifs_sb->ctx->prepath = NULL; > + > rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, old_ctx->UNC); > if (rc) { > root = ERR_PTR(rc); > -- > 2.26.2 >