[PATCH v2 07/10] nfsd: return NFS4ERR_NOTSUPP for unsupported netloc4 types

[Jeff Layton <jlayton@kernel.org>]

nfsd4_decode_nl4_server() handled only NL4_NETADDR and returned
nfserr_bad_xdr for NL4_NAME and NL4_URL. Those forms are well-formed XDR,
so BADXDR is misleading -- the request is unsupported, not malformed.

Decode and discard the utf8str_cis for NL4_NAME and NL4_URL to keep the
stream consistent, and return nfserr_notsupp. nfsd4_proc_compound() honors
a decode-time op->status, so the op fails without executing.

Fixes: 84e1b21d5ec4 ("NFSD add ca_source_server<> to COPY")
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/nfsd/nfs4xdr.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index aef48fb0fac2..23f50a947bf1 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2123,6 +2123,7 @@ static __be32 nfsd4_decode_nl4_server(struct nfsd4_compoundargs *argp,
 {
 	struct nfs42_netaddr *naddr;
 	__be32 *p;
+	u32 str_len;
 
 	if (xdr_stream_decode_u32(argp->xdr, &ns->nl4_type) < 0)
 		return nfserr_bad_xdr;
@@ -2152,6 +2153,20 @@ static __be32 nfsd4_decode_nl4_server(struct nfsd4_compoundargs *argp,
 			return nfserr_bad_xdr;
 		memcpy(naddr->addr, p, naddr->addr_len);
 		break;
+	case NL4_NAME:
+	case NL4_URL:
+		/*
+		 * A netloc name or URL is well-formed XDR, but this server
+		 * only supports NL4_NETADDR.  Consume the utf8str_cis so the
+		 * stream stays aligned for any following operations, then
+		 * reject the operation with NFS4ERR_NOTSUPP rather than the
+		 * misleading NFS4ERR_BADXDR.
+		 */
+		if (xdr_stream_decode_u32(argp->xdr, &str_len) < 0)
+			return nfserr_bad_xdr;
+		if (!xdr_inline_decode(argp->xdr, str_len))
+			return nfserr_bad_xdr;
+		return nfserr_notsupp;
 	default:
 		return nfserr_bad_xdr;
 	}

-- 
2.55.0