From 5283b03ee5cd28d516646298bead09b238d92ddc Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Fri, 24 Feb 2017 13:25:24 -0500 Subject: [PATCH] nfs/nfsd/sunrpc: enforce transport requirements for NFSv4 NFSv4 requires a transport "that is specified to avoid network congestion" (RFC 7530, section 3.1, paragraph 2). In practical terms, that means that you should not run NFSv4 over UDP. The server has never enforced that requirement, however. This patchset fixes this by adding a new flag to the svc_version that states that it has these transport requirements. With that, we can check that the transport has XPT_CONG_CTRL set before processing an RPC. If it doesn't we reject it with RPC_PROG_MISMATCH. Signed-off-by: Jeff Layton Signed-off-by: J. Bruce Fields --- fs/nfs/callback_xdr.c | 2 ++ fs/nfsd/nfs4proc.c | 13 +++++++------ include/linux/sunrpc/svc.h | 3 +++ net/sunrpc/svc.c | 15 +++++++++++++++ 4 files changed, 27 insertions(+), 6 deletions(-) diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c index e9836f611d9c..fd0284c1dc32 100644 --- a/fs/nfs/callback_xdr.c +++ b/fs/nfs/callback_xdr.c @@ -1084,6 +1084,7 @@ struct svc_version nfs4_callback_version1 = { .vs_xdrsize = NFS4_CALLBACK_XDRSIZE, .vs_dispatch = NULL, .vs_hidden = true, + .vs_need_cong_ctrl = true, }; struct svc_version nfs4_callback_version4 = { @@ -1093,4 +1094,5 @@ struct svc_version nfs4_callback_version4 = { .vs_xdrsize = NFS4_CALLBACK_XDRSIZE, .vs_dispatch = NULL, .vs_hidden = true, + .vs_need_cong_ctrl = true, }; diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index 89e582fa58cd..cbeeda1e94a2 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -2537,12 +2537,13 @@ static struct svc_procedure nfsd_procedures4[2] = { }; struct svc_version nfsd_version4 = { - .vs_vers = 4, - .vs_nproc = 2, - .vs_proc = nfsd_procedures4, - .vs_dispatch = nfsd_dispatch, - .vs_xdrsize = NFS4_SVC_XDRSIZE, - .vs_rpcb_optnl = true, + .vs_vers = 4, + .vs_nproc = 2, + .vs_proc = nfsd_procedures4, + .vs_dispatch = nfsd_dispatch, + .vs_xdrsize = NFS4_SVC_XDRSIZE, + .vs_rpcb_optnl = true, + .vs_need_cong_ctrl = true, }; /* diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h index 96467c95f02e..e770abeed32d 100644 --- a/include/linux/sunrpc/svc.h +++ b/include/linux/sunrpc/svc.h @@ -406,6 +406,9 @@ struct svc_version { /* Don't care if the rpcbind registration fails */ bool vs_rpcb_optnl; + /* Need xprt with congestion control */ + bool vs_need_cong_ctrl; + /* Override dispatch function (e.g. when caching replies). * A return value of 0 means drop the request. * vs_dispatch == NULL means use default dispatcher. diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c index 85bcdea67a3f..1fc3ff822168 100644 --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -1169,6 +1169,21 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv) !(versp = progp->pg_vers[vers])) goto err_bad_vers; + /* + * Some protocol versions (namely NFSv4) require some form of + * congestion control. (See RFC 7530 section 3.1 paragraph 2) + * In other words, UDP is not allowed. We mark those when setting + * up the svc_xprt, and verify that here. + * + * The spec is not very clear about what error should be returned + * when someone tries to access a server that is listening on UDP + * for lower versions. RPC_PROG_MISMATCH seems to be the closest + * fit. + */ + if (versp->vs_need_cong_ctrl && + !test_bit(XPT_CONG_CTRL, &rqstp->rq_xprt->xpt_flags)) + goto err_bad_vers; + procp = versp->vs_proc + proc; if (proc >= versp->vs_nproc || !procp->pc_func) goto err_bad_proc; -- 2.20.1