From patchwork Mon Jan 2 17:05:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever X-Patchwork-Id: 13086853 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B990DC3DA7A for ; Mon, 2 Jan 2023 17:06:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235326AbjABRGA (ORCPT ); Mon, 2 Jan 2023 12:06:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52992 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236188AbjABRF7 (ORCPT ); Mon, 2 Jan 2023 12:05:59 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF00A64DE for ; Mon, 2 Jan 2023 09:05:58 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 74F7C60F79 for ; Mon, 2 Jan 2023 17:05:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B9C1EC433EF for ; Mon, 2 Jan 2023 17:05:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1672679157; bh=4Dg0X8b/OAe/y83wjuPsvvei15+aA28xvkB2os7hn50=; h=Subject:From:To:Date:In-Reply-To:References:From; b=Bp0jOBzDOk4nVyyEtjwPCCmGKpPv0ZB1BmAFQHuCe0c0ENT518oTFBfCGFOThxPxQ iJMsx3LL9TDS4hJO6qjtDh6oBJQ4yd2mzdpLhkA01EVzhW/Z2PWwn2F3FDcKUcHlIx RH/FcAnJh5I+BqNFqwr9vlbZtWEtZQziZ3Y1A+UWuD2Vla9hkHw5cZRyy8+UMnle2B sn0olQ+XCUAnl98/dcJw3TrPi6YQOj/Jp4FvAFrmDCY283XBrbLb+sjlcODM2HDYUx D3ATsTPbfF2xBx9VBoxT81Zk+w9gaen464MYEbtX+u+9C9osWZGP8bS2JCPurDw7O7 6NJg4DYR4tIpA== Subject: [PATCH v1 05/25] SUNRPC: Convert svcauth_unix_accept() to use xdr_stream From: Chuck Lever To: linux-nfs@vger.kernel.org Date: Mon, 02 Jan 2023 12:05:56 -0500 Message-ID: <167267915666.112521.3772441945439792226.stgit@manet.1015granger.net> In-Reply-To: <167267753484.112521.4826748148788735127.stgit@manet.1015granger.net> References: <167267753484.112521.4826748148788735127.stgit@manet.1015granger.net> User-Agent: StGit/1.5.dev2+g9ce680a5 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org From: Chuck Lever Done as part of hardening the server-side RPC header decoding path. Since the server-side of the Linux kernel SunRPC implementation ignores the contents of the Call's machinename field, there's no need for its RPC_AUTH_UNIX authenticator to reject names that are larger than UNX_MAXNODENAME. Signed-off-by: Chuck Lever --- include/linux/sunrpc/msg_prot.h | 5 +++ net/sunrpc/svcauth_unix.c | 71 ++++++++++++++++++++++++++++----------- 2 files changed, 56 insertions(+), 20 deletions(-) diff --git a/include/linux/sunrpc/msg_prot.h b/include/linux/sunrpc/msg_prot.h index 02117ed0fa2e..c4b0eb2b2f04 100644 --- a/include/linux/sunrpc/msg_prot.h +++ b/include/linux/sunrpc/msg_prot.h @@ -34,6 +34,11 @@ enum rpc_auth_flavors { RPC_AUTH_GSS_SPKMP = 390011, }; +/* Maximum size (in octets) of the machinename in an AUTH_UNIX + * credential (per RFC 5531 Appendix A) + */ +#define RPC_MAX_MACHINENAME (255) + /* Maximum size (in bytes) of an rpc credential or verifier */ #define RPC_MAX_AUTH_SIZE (400) diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c index 95354f03bb05..b6aef9c5113b 100644 --- a/net/sunrpc/svcauth_unix.c +++ b/net/sunrpc/svcauth_unix.c @@ -867,26 +867,45 @@ struct auth_ops svcauth_tls = { }; +/** + * svcauth_unix_accept - Decode and validate incoming RPC_AUTH_SYS credential + * @rqstp: RPC transaction + * + * Return values: + * %SVC_OK: Both credential and verifier are valid + * %SVC_DENIED: Credential or verifier is not valid + * %SVC_GARBAGE: Failed to decode credential or verifier + * %SVC_CLOSE: Temporary failure + * + * rqstp->rq_auth_stat is set as mandated by RFC 5531. + */ static int svcauth_unix_accept(struct svc_rqst *rqstp) { - struct kvec *argv = &rqstp->rq_arg.head[0]; struct kvec *resv = &rqstp->rq_res.head[0]; + struct xdr_stream *xdr = &rqstp->rq_arg_stream; struct svc_cred *cred = &rqstp->rq_cred; struct user_namespace *userns; - u32 slen, i; - int len = argv->iov_len; + u32 flavor, len, i; + void *body; + __be32 *p; + + svcxdr_init_decode(rqstp); - if ((len -= 3*4) < 0) + /* + * This implementation ignores the length of the Call's + * credential body field and the timestamp and machinename + * fields. + */ + p = xdr_inline_decode(xdr, XDR_UNIT * 3); + if (!p) + return SVC_GARBAGE; + len = be32_to_cpup(p + 2); + if (len > RPC_MAX_MACHINENAME) + return SVC_GARBAGE; + if (!xdr_inline_decode(xdr, len)) return SVC_GARBAGE; - svc_getu32(argv); /* length */ - svc_getu32(argv); /* time stamp */ - slen = XDR_QUADLEN(svc_getnl(argv)); /* machname length */ - if (slen > 64 || (len -= (slen + 3)*4) < 0) - goto badcred; - argv->iov_base = (void*)((__be32*)argv->iov_base + slen); /* skip machname */ - argv->iov_len -= slen*4; /* * Note: we skip uid_valid()/gid_valid() checks here for * backwards compatibility with clients that use -1 id's. @@ -896,20 +915,33 @@ svcauth_unix_accept(struct svc_rqst *rqstp) */ userns = (rqstp->rq_xprt && rqstp->rq_xprt->xpt_cred) ? rqstp->rq_xprt->xpt_cred->user_ns : &init_user_ns; - cred->cr_uid = make_kuid(userns, svc_getnl(argv)); /* uid */ - cred->cr_gid = make_kgid(userns, svc_getnl(argv)); /* gid */ - slen = svc_getnl(argv); /* gids length */ - if (slen > UNX_NGROUPS || (len -= (slen + 2)*4) < 0) + if (xdr_stream_decode_u32(xdr, &i) < 0) + return SVC_GARBAGE; + cred->cr_uid = make_kuid(userns, i); + if (xdr_stream_decode_u32(xdr, &i) < 0) + return SVC_GARBAGE; + cred->cr_gid = make_kgid(userns, i); + + if (xdr_stream_decode_u32(xdr, &len) < 0) + return SVC_GARBAGE; + if (len > UNX_NGROUPS) goto badcred; - cred->cr_group_info = groups_alloc(slen); + p = xdr_inline_decode(xdr, XDR_UNIT * len); + if (!p) + return SVC_GARBAGE; + cred->cr_group_info = groups_alloc(len); if (cred->cr_group_info == NULL) return SVC_CLOSE; - for (i = 0; i < slen; i++) { - kgid_t kgid = make_kgid(userns, svc_getnl(argv)); + for (i = 0; i < len; i++) { + kgid_t kgid = make_kgid(userns, be32_to_cpup(p++)); cred->cr_group_info->gid[i] = kgid; } groups_sort(cred->cr_group_info); - if (svc_getu32(argv) != htonl(RPC_AUTH_NULL) || svc_getu32(argv) != 0) { + + /* Call's verf field: */ + if (xdr_stream_decode_opaque_auth(xdr, &flavor, &body, &len) < 0) + return SVC_GARBAGE; + if (flavor != RPC_AUTH_NULL || len != 0) { rqstp->rq_auth_stat = rpc_autherr_badverf; return SVC_DENIED; } @@ -919,7 +951,6 @@ svcauth_unix_accept(struct svc_rqst *rqstp) svc_putnl(resv, 0); rqstp->rq_cred.cr_flavor = RPC_AUTH_UNIX; - svcxdr_init_decode(rqstp); return SVC_OK; badcred: