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=-12.7 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 B6F5BC433ED for ; Sat, 1 May 2021 10:53:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8789E61042 for ; Sat, 1 May 2021 10:53:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231895AbhEAKyq (ORCPT ); Sat, 1 May 2021 06:54:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59168 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231893AbhEAKyq (ORCPT ); Sat, 1 May 2021 06:54:46 -0400 Received: from mail-yb1-xb2e.google.com (mail-yb1-xb2e.google.com [IPv6:2607:f8b0:4864:20::b2e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0D522C06174A for ; Sat, 1 May 2021 03:53:55 -0700 (PDT) Received: by mail-yb1-xb2e.google.com with SMTP id 82so1255375yby.7 for ; Sat, 01 May 2021 03:53:54 -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=z/+evurKQGdx4mRvTGVqB4aF4LzSUkkU+WTbVfw05kw=; b=j6E+FgyIpGQ/riBiixy851wY+VHxXqdSHZ2fx1F1ijnRtqcqStkNKjjyRbZj8xz36F iQtrZG4m4y+i4DKzazZcNbyiJ+pvIbyTLmmuKaFQXemCX9ezvBW3IJh2S95k56sqOdED sG51FBdgN8KOq4/+Fwh3nM0hSRwtMOaIIjU35Ud9zoVrBIzdLPt25ceQPsvnlNZGdepL ZKYYw4C4B4OMUwrustR5PDHvnnuwcB8Py60U8P2nSo2NTFpE+uKdd7ME/2r6S44S/T6S eUEfNt7nlOhoEWYLOcAqisSiSfwpfvEWxEjIbVhAp91CvR0Oel3yVdAvXmNzfx40aBXI c9HQ== 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=z/+evurKQGdx4mRvTGVqB4aF4LzSUkkU+WTbVfw05kw=; b=pFQwkU1UwWNh6x0rXGrnkugURqrGkxhZ2iu+tUtSsdGjqbt5G9BjLzBGIAJaso96ie Y8fjZA6Z3lmWut/RWGtuyzeGXx+w9jHC67PxZaPfy4ZwqdYiL7EOLVaKgF4ye8JSRG3b gLXgEl389rtq6NiHKLOLaQgGBYYxZPnIE5PlbEJG2l9J0LiqBr3J6TXPZMlPsZvkQt+t TmCwEoQT9dcQCw0shYH+146cQ7tP3yzcoVZRkEWySEW24csPkYKB9SkAkkd4cM/jSxLk v2M6GN9HHUmdnrS9LcGNYgN1VzWL9pwjn3PLcMMjlnDSnCeJBLL8Q1pxprxp6RiQ4v8Y 7Rog== X-Gm-Message-State: AOAM5321pAWsq4tTh1PcKJwbVDfeeF4CKc2RJF1olJRWN5T8t0+FnJH8 kwBDmNxOs8n5VQRXWUL/6Sdo2iWr9mld83wIly0= X-Google-Smtp-Source: ABdhPJzC1YqpePeZ+Jgf6TB2VcnQoAIdvvWk3WYI+nd7v6ex7yhFBJZYIPnSeskPJVFE6DPvIcHkiWkJnZusN4ABDcc= X-Received: by 2002:a25:b84a:: with SMTP id b10mr10276573ybm.327.1619866434025; Sat, 01 May 2021 03:53:54 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Shyam Prasad N Date: Sat, 1 May 2021 16:23:42 +0530 Message-ID: Subject: Re: [PATCH] smb3.1.1: allow dumping GCM256 keys to improve debugging of encrypted shares To: Steve French Cc: ronnie sahlberg , CIFS , samba-technical , COMMON INTERNET FILE SYSTEM SERVER Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Looks good to me. On a related note, we need a way for the root user to dump keys for another SMB session to the same path. This will be useful for mutli-user scenario. i.e. for dumping keys for SMB session as another user. Since we're adding a new IOCTL, perhaps we should add another arg which identifies the user? Maybe based on the UID:GID of the user session, in addition to the path supplied? Regards, Shyam On Sat, May 1, 2021 at 9:49 AM Steve French wrote: > > changed as suggested - see attached > > On Fri, Apr 30, 2021 at 11:00 PM ronnie sahlberg > wrote: > > > > These elements should probably be [32] and not > > + __u8 smb3encryptionkey[SMB3_ENC_DEC_KEY_SIZE]; > > > > Because this is now visible to userspace and we can not allow this to > > ever change. > > Because when GCM512 is eventually released, if we bump > > SMB3_ENC_DEC_KEY_SIZE to a larger value we suddenly break userspace. > > > > > > On Sat, May 1, 2021 at 8:20 AM Steve French wrote: > > > > > > Previously we were only able to dump CCM or GCM-128 keys (see "smbinfo > > > keys" e.g.) > > > to allow network debugging (e.g. wireshark) of mounts to SMB3.1.1 encrypted > > > shares. But with the addition of GCM-256 support, we have to be able to dump > > > 32 byte instead of 16 byte keys which requires adding an additional ioctl > > > for that. > > > > > > Signed-off-by: Steve French > > > --- > > > fs/cifs/cifs_ioctl.h | 19 +++++++++++++++++++ > > > fs/cifs/ioctl.c | 33 +++++++++++++++++++++++++++++++++ > > > 2 files changed, 52 insertions(+) > > > > > > diff --git a/fs/cifs/cifs_ioctl.h b/fs/cifs/cifs_ioctl.h > > > index f262c64516bc..9f2ed9cccb08 100644 > > > --- a/fs/cifs/cifs_ioctl.h > > > +++ b/fs/cifs/cifs_ioctl.h > > > @@ -57,6 +57,12 @@ struct smb_query_info { > > > /* char buffer[]; */ > > > } __packed; > > > > > > +/* > > > + * Dumping the commonly used 16 byte (e.g. CCM and GCM128) keys still supported > > > + * for backlevel compatibility, but is not sufficient for dumping the less > > > + * frequently used GCM256 (32 byte) keys (see the newer "CIFS_DUMP_FULL_KEY" > > > + * ioctl for dumping decryption info for GCM256 mounts) > > > + */ > > > struct smb3_key_debug_info { > > > __u64 Suid; > > > __u16 cipher_type; > > > @@ -65,6 +71,18 @@ struct smb3_key_debug_info { > > > __u8 smb3decryptionkey[SMB3_SIGN_KEY_SIZE]; > > > } __packed; > > > > > > +/* > > > + * Dump full key (32 byte encrypt/decrypt keys instead of 16 bytes) > > > + * is needed if GCM256 (stronger encryption) negotiated > > > + */ > > > +struct smb3_full_key_debug_info { > > > + __u64 Suid; > > > + __u16 cipher_type; > > > + __u8 auth_key[16]; /* SMB2_NTLMV2_SESSKEY_SIZE */ > > > + __u8 smb3encryptionkey[SMB3_ENC_DEC_KEY_SIZE]; > > > + __u8 smb3decryptionkey[SMB3_ENC_DEC_KEY_SIZE]; > > > +} __packed; > > > + > > > struct smb3_notify { > > > __u32 completion_filter; > > > bool watch_tree; > > > @@ -78,6 +96,7 @@ struct smb3_notify { > > > #define CIFS_QUERY_INFO _IOWR(CIFS_IOCTL_MAGIC, 7, struct smb_query_info) > > > #define CIFS_DUMP_KEY _IOWR(CIFS_IOCTL_MAGIC, 8, struct smb3_key_debug_info) > > > #define CIFS_IOC_NOTIFY _IOW(CIFS_IOCTL_MAGIC, 9, struct smb3_notify) > > > +#define CIFS_DUMP_FULL_KEY _IOWR(CIFS_IOCTL_MAGIC, 10, struct > > > smb3_full_key_debug_info) > > > #define CIFS_IOC_SHUTDOWN _IOR ('X', 125, __u32) > > > > > > /* > > > diff --git a/fs/cifs/ioctl.c b/fs/cifs/ioctl.c > > > index ef41fa878793..e4321e2a27d2 100644 > > > --- a/fs/cifs/ioctl.c > > > +++ b/fs/cifs/ioctl.c > > > @@ -218,6 +218,7 @@ long cifs_ioctl(struct file *filep, unsigned int > > > command, unsigned long arg) > > > { > > > struct inode *inode = file_inode(filep); > > > struct smb3_key_debug_info pkey_inf; > > > + struct smb3_full_key_debug_info pfull_key_inf; > > > int rc = -ENOTTY; /* strange error - but the precedent */ > > > unsigned int xid; > > > struct cifsFileInfo *pSMBFile = filep->private_data; > > > @@ -354,6 +355,38 @@ long cifs_ioctl(struct file *filep, unsigned int > > > command, unsigned long arg) > > > else > > > rc = 0; > > > break; > > > + /* > > > + * Dump full key (32 bytes instead of 16 bytes) is > > > + * needed if GCM256 (stronger encryption) negotiated > > > + */ > > > + case CIFS_DUMP_FULL_KEY: > > > + if (pSMBFile == NULL) > > > + break; > > > + if (!capable(CAP_SYS_ADMIN)) { > > > + rc = -EACCES; > > > + break; > > > + } > > > + > > > + tcon = tlink_tcon(pSMBFile->tlink); > > > + if (!smb3_encryption_required(tcon)) { > > > + rc = -EOPNOTSUPP; > > > + break; > > > + } > > > + pfull_key_inf.cipher_type = > > > + le16_to_cpu(tcon->ses->server->cipher_type); > > > + pfull_key_inf.Suid = tcon->ses->Suid; > > > + memcpy(pfull_key_inf.auth_key, tcon->ses->auth_key.response, > > > + 16 /* SMB2_NTLMV2_SESSKEY_SIZE */); > > > + memcpy(pfull_key_inf.smb3decryptionkey, > > > + tcon->ses->smb3decryptionkey, SMB3_ENC_DEC_KEY_SIZE); > > > + memcpy(pfull_key_inf.smb3encryptionkey, > > > + tcon->ses->smb3encryptionkey, SMB3_ENC_DEC_KEY_SIZE); > > > + if (copy_to_user((void __user *)arg, &pfull_key_inf, > > > + sizeof(struct smb3_full_key_debug_info))) > > > + rc = -EFAULT; > > > + else > > > + rc = 0; > > > + break; > > > case CIFS_IOC_NOTIFY: > > > if (!S_ISDIR(inode->i_mode)) { > > > /* Notify can only be done on directories */ > > > > > > -- > > > Thanks, > > > > > > Steve > > > > -- > Thanks, > > Steve -- Regards, Shyam