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[209.132.180.67]) by mx.google.com with ESMTP id t2si124343oih.136.2020.03.25.14.44.02; Wed, 25 Mar 2020 14:44:15 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-nfs-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2020-01-29 header.b=bR75y6QO; spf=pass (google.com: best guess record for domain of linux-nfs-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-nfs-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726947AbgCYVn5 (ORCPT + 99 others); Wed, 25 Mar 2020 17:43:57 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:49174 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726081AbgCYVn5 (ORCPT ); Wed, 25 Mar 2020 17:43:57 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 02PLdB2x188465; Wed, 25 Mar 2020 21:43:52 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=content-type : mime-version : subject : from : in-reply-to : date : cc : content-transfer-encoding : message-id : references : to; s=corp-2020-01-29; bh=m93WJO/1bI2NK4wYUrcEILpXGf96lS94O1ksi02zQ+g=; b=bR75y6QOjpcQvJKBaoexY7INu/FLb0wkU+PzClCo783I4715dUMU3tS9rZsv96xRsbAo QbJgt26p63vqh1Wvb49L1U4yDhATrzIa6Sq4Y1eUU1EtPfbhH3QikswOdHVzvL9UC2DM Yb73UlVEwBV4QTxbjxaCcQcb/QufAVai4hvrATlINmd2nBOoErH7+vljBib+lkyu7RSm zMKs2Tsu4S/sI9SaCm41+Z0bJIUCt0BPTfPwHUvgJ/nDrYpn7GRMnwI4BtZi11rQAV/z UNU9XjQxy5hV3SZ8rYFeoHl1ehKJIbSuncAlzBZz2TO96W87wVC8TG0yd1p+qMPdAL4C cQ== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by aserp2120.oracle.com with ESMTP id 2ywavmca36-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 25 Mar 2020 21:43:52 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 02PLWWXh096214; Wed, 25 Mar 2020 21:43:51 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userp3030.oracle.com with ESMTP id 2yxw4s9v5y-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 25 Mar 2020 21:43:51 +0000 Received: from abhmp0013.oracle.com (abhmp0013.oracle.com [141.146.116.19]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 02PLhn9W020482; Wed, 25 Mar 2020 21:43:49 GMT Received: from anon-dhcp-153.1015granger.net (/68.61.232.219) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 25 Mar 2020 14:43:49 -0700 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.11\)) Subject: Re: [PATCH 1/1] SUNRPC: fix krb5p mount to provide large enough buffer in rq_rcvsize From: Chuck Lever In-Reply-To: <7363e7b550dc5adad3f00fb84d9586764b8ec4fb.camel@hammerspace.com> Date: Wed, 25 Mar 2020 17:43:47 -0400 Cc: Anna Schumaker , Olga Kornievskaia , Linux NFS Mailing List Content-Transfer-Encoding: quoted-printable Message-Id: <8A8EC7E8-9EB6-49DA-8393-241B4977E67E@oracle.com> References: <20200325210136.2826-1-olga.kornievskaia@gmail.com> <7363e7b550dc5adad3f00fb84d9586764b8ec4fb.camel@hammerspace.com> To: Trond Myklebust X-Mailer: Apple Mail (2.3445.104.11) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9571 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 suspectscore=2 spamscore=0 mlxlogscore=999 adultscore=0 phishscore=0 mlxscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2003250166 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9571 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 malwarescore=0 priorityscore=1501 mlxscore=0 bulkscore=0 clxscore=1015 impostorscore=0 phishscore=0 suspectscore=2 mlxlogscore=999 spamscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2003250166 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org > On Mar 25, 2020, at 5:33 PM, Trond Myklebust = wrote: >=20 > Hi Olga, >=20 > On Wed, 2020-03-25 at 17:01 -0400, Olga Kornievskaia wrote: >> From: Olga Kornievskaia >>=20 >> Ever since commit 2c94b8eca1a2 ("SUNRPC: Use au_rslack when computing >> reply buffer size"). It changed how "req->rq_rcvsize" is calculated. >> It >> used to use au_cslack value which was nice and large and changed it >> to >> au_rslack value which turns out to be too small. >>=20 >> Since 5.1, v3 mount with sec=3Dkrb5p fails against an Ontap server >> because client's receive buffer it too small. >>=20 >> For gss krb5p, we need to account for the mic token in the verifier, >> and the wrap token in the wrap token. >>=20 >> RFC 4121 defines: >> mic token >> Octet no Name Description >> ---------------------------------------------------------- >> ---- >> 0..1 TOK_ID Identification field. Tokens emitted by >> GSS_GetMIC() contain the hex value 04 04 >> expressed in big-endian order in this >> field. >> 2 Flags Attributes field, as described in >> section >> 4.2.2. >> 3..7 Filler Contains five octets of hex value FF. >> 8..15 SND_SEQ Sequence number field in clear text, >> expressed in big-endian order. >> 16..last SGN_CKSUM Checksum of the "to-be-signed" data and >> octet 0..15, as described in section >> 4.2.4. >>=20 >> that's 16bytes (GSS_KRB5_TOK_HDR_LEN) + chksum >>=20 >> wrap token >> Octet no Name Description >> ---------------------------------------------------------- >> ---- >> 0..1 TOK_ID Identification field. Tokens emitted by >> GSS_Wrap() contain the hex value 05 04 >> expressed in big-endian order in this >> field. >> 2 Flags Attributes field, as described in >> section >> 4.2.2. >> 3 Filler Contains the hex value FF. >> 4..5 EC Contains the "extra count" field, in >> big- >> endian order as described in section >> 4.2.3. >> 6..7 RRC Contains the "right rotation count" in >> big- >> endian order, as described in section >> 4.2.5. >> 8..15 SND_SEQ Sequence number field in clear text, >> expressed in big-endian order. >> 16..last Data Encrypted data for Wrap tokens with >> confidentiality, or plaintext data >> followed >> by the checksum for Wrap tokens without >> confidentiality, as described in section >> 4.2.4. >>=20 >> Also 16bytes of header (GSS_KRB5_TOK_HDR_LEN), encrypted data, and >> cksum >> (other things like padding) >>=20 >> RFC 3961 defines known cksum sizes: >> Checksum type sumtype checksum section or >> value size referen >> ce >> ---------------------------------------------------------------- >> ----- >> CRC32 1 4 6.1.3 >> rsa-md4 2 16 6.1.2 >> rsa-md4-des 3 24 6.2.5 >> des-mac 4 16 6.2.7 >> des-mac-k 5 8 6.2.8 >> rsa-md4-des-k 6 16 6.2.6 >> rsa-md5 7 16 6.1.1 >> rsa-md5-des 8 24 6.2.4 >> rsa-md5-des3 9 24 ?? >> sha1 (unkeyed) 10 20 ?? >> hmac-sha1-des3-kd 12 20 6.3 >> hmac-sha1-des3 13 20 ?? >> sha1 (unkeyed) 14 20 ?? >> hmac-sha1-96-aes128 15 20 [KRB5- >> AES] >> hmac-sha1-96-aes256 16 20 [KRB5- >> AES] >> [reserved] 0x8003 ? [GSS- >> KRB5] >>=20 >> Linux kernel now mainly supports type 15,16 so max cksum size is >> 20bytes. >> (GSS_KRB5_MAX_CKSUM_LEN) >>=20 >> Re-use already existing define of GSS_KRB5_MAX_SLACK_NEEDED that's >> used >> for encoding the gss_wrap tokens (same tokens are used in reply). >>=20 >> Fixes: 2c94b8eca1a2 ("SUNRPC: Use au_rslack when computing reply >> buffer size") >> Signed-off-by: Olga Kornievskaia >> --- >> net/sunrpc/auth_gss/auth_gss.c | 5 ++++- >> 1 file changed, 4 insertions(+), 1 deletion(-) >>=20 >> diff --git a/net/sunrpc/auth_gss/auth_gss.c >> b/net/sunrpc/auth_gss/auth_gss.c >> index 24ca861..5a733a6 100644 >> --- a/net/sunrpc/auth_gss/auth_gss.c >> +++ b/net/sunrpc/auth_gss/auth_gss.c >> @@ -20,6 +20,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> #include >> @@ -51,6 +52,8 @@ >> /* length of a krb5 verifier (48), plus data added before arguments >> when >> * using integrity (two 4-byte integers): */ >> #define GSS_VERF_SLACK 100 >> +/* covers lengths of gss_unwrap() extra kerberos mic and wrap token >> */ >> +#define GSS_RESP_SLACK (GSS_KRB5_MAX_SLACK_NEEDED << >> 2) >>=20 >> static DEFINE_HASHTABLE(gss_auth_hash_table, 4); >> static DEFINE_SPINLOCK(gss_auth_hash_lock); >> @@ -1050,7 +1053,7 @@ static void gss_pipe_free(struct gss_pipe *p) >> goto err_put_mech; >> auth =3D &gss_auth->rpc_auth; >> auth->au_cslack =3D GSS_CRED_SLACK >> 2; >> - auth->au_rslack =3D GSS_VERF_SLACK >> 2; >> + auth->au_rslack =3D GSS_RESP_SLACK >> 2; >> auth->au_verfsize =3D GSS_VERF_SLACK >> 2; >> auth->au_ralign =3D GSS_VERF_SLACK >> 2; >> auth->au_flags =3D 0; >=20 > Is this a sufficient fix, though? It looks to me as if the above is > just an initial value that gets adjusted on the fly in > gss_unwrap_resp_priv(): >=20 > auth->au_rslack =3D auth->au_verfsize + 2 + > XDR_QUADLEN(savedlen - rcv_buf->len); > auth->au_ralign =3D auth->au_verfsize + 2 + > XDR_QUADLEN(savedlen - rcv_buf->len); That's correct. The GSS_*_SLACK value is a _sz value that is the largest possible expected size of the extra GSS data. > My questions would be >=20 > - Are we sure that the above calculation (in gss_unwrap_resp_priv()) = is > correct? Yes, this is the correct computation. We know this because if the initial au_rslack value is large enough, then subsequent Replies have the correct amount of buffer space and always succeed. > - Are we sure that the above calculation always gives the same answer > over time? We probably should not store a value that keeps changing. It does not change after the first Reply. au_rslack is typically adjusted downwards from the initial value based on the size of the first received Reply. Not setting these variables after the first Reply has been received would be a minor optimization that could be done after Olga's fix. -- Chuck Lever