From: Chuck Lever <chuck.lever@oracle.com>
Date: Tue, 2 May 2023 14:59:10 -0400
Subject: SUNRPC: Fix encoding of accepted but unsuccessful RPC replies
Git-commit: 29cd2927fb914cc53b5ba4f67d2b74695c994ba4
Patch-mainline: 6.4-rc3
References: bsc#1210995
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 EIO
Reported-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")
Tested-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
net/sunrpc/svc.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1382,7 +1382,7 @@ err_bad_rpc:
/* 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 @@ err_bad_auth:
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 @@ err_bad_vers:
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 @@ err_bad_proc:
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;
}