[PATCH] SUNRPC: Fix encoding of rejected RPCs
From: Chuck Lever <cel@kernel.org>
Date: 2023-05-02 18:59:16
Subsystem:
kernel nfsd, sunrpc, and lockd servers, networking [general], nfs, sunrpc, and lockd clients, the rest · Maintainers:
Chuck Lever, Jeff Layton, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Trond Myklebust, Anna Schumaker, Linus Torvalds
From: Chuck Lever <redacted> Jiri Slaby says:
I bisected to this ... as it breaks nfs3-only servers in 6.3.
I.e. /etc/nfs.conf containing:
[nfsd]
vers4=no
The client sees:
mount("10.0.2.15:/tmp", "/mnt", "nfs", 0, "vers=4.2,addr=10.0.2.15,clientad"...) = -1 EIO (Input/output error)
write(2, "mount.nfs: mount system call fai"..., 45
mount.nfs: mount system call failed for /mnt
And the kernel says:
nfs4_discover_server_trunking unhandled error -5. Exiting with error EIOReported-by: Jiri Slaby <jirislaby@kernel.org> Link: https://bugzilla.suse.com/show_bug.cgi?id=1210995 Fixes: 4bcf0343e8a6 ("SUNRPC: Set rq_accept_statp inside ->accept methods") Signed-off-by: Chuck Lever <redacted> --- net/sunrpc/svc.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index fea7ce8fba14..9874a6de1de3 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c@@ -1382,7 +1382,7 @@ svc_process_common(struct svc_rqst *rqstp) /* Only RPCv2 supported */ xdr_stream_encode_u32(xdr, RPC_VERSION); xdr_stream_encode_u32(xdr, RPC_VERSION); - goto sendit; + return 1; /* don't wrap */ err_bad_auth: dprintk("svc: authentication failed (%d)\n",
@@ -1398,7 +1398,7 @@ svc_process_common(struct svc_rqst *rqstp) err_bad_prog: dprintk("svc: unknown program %d\n", rqstp->rq_prog); serv->sv_stats->rpcbadfmt++; - xdr_stream_encode_u32(xdr, RPC_PROG_UNAVAIL); + *rqstp->rq_accept_statp = rpc_prog_unavail; goto sendit; err_bad_vers:
@@ -1406,7 +1406,12 @@ svc_process_common(struct svc_rqst *rqstp) rqstp->rq_vers, rqstp->rq_prog, progp->pg_name); serv->sv_stats->rpcbadfmt++; - xdr_stream_encode_u32(xdr, RPC_PROG_MISMATCH); + *rqstp->rq_accept_statp = rpc_prog_mismatch; + + /* + * svc_authenticate() has already added the verifier and + * advanced the stream just past rq_accept_statp. + */ xdr_stream_encode_u32(xdr, process.mismatch.lovers); xdr_stream_encode_u32(xdr, process.mismatch.hivers); goto sendit;
@@ -1415,19 +1420,19 @@ svc_process_common(struct svc_rqst *rqstp) svc_printk(rqstp, "unknown procedure (%d)\n", rqstp->rq_proc); serv->sv_stats->rpcbadfmt++; - xdr_stream_encode_u32(xdr, RPC_PROC_UNAVAIL); + *rqstp->rq_accept_statp = rpc_proc_unavail; goto sendit; err_garbage_args: svc_printk(rqstp, "failed to decode RPC header\n"); serv->sv_stats->rpcbadfmt++; - xdr_stream_encode_u32(xdr, RPC_GARBAGE_ARGS); + *rqstp->rq_accept_statp = rpc_garbage_args; goto sendit; err_system_err: serv->sv_stats->rpcbadfmt++; - xdr_stream_encode_u32(xdr, RPC_SYSTEM_ERR); + *rqstp->rq_accept_statp = rpc_system_err; goto sendit; }