nfsd4: check backchannel attributes on create_session
Make sure the client gives us an adequate backchannel.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 036d5f1..67017fc 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -42,6 +42,7 @@
#include <linux/sunrpc/svcauth_gss.h>
#include <linux/sunrpc/addr.h>
#include "xdr4.h"
+#include "xdr4cb.h"
#include "vfs.h"
#include "current_stateid.h"
@@ -1794,6 +1795,27 @@
return nfs_ok;
}
+static __be32 check_backchannel_attrs(struct nfsd4_channel_attrs *ca)
+{
+ ca->headerpadsz = 0;
+
+ /*
+ * These RPC_MAX_HEADER macros are overkill, especially since we
+ * don't even do gss on the backchannel yet. But this is still
+ * less than 1k. Tighten up this estimate in the unlikely event
+ * it turns out to be a problem for some client:
+ */
+ if (ca->maxreq_sz < NFS4_enc_cb_recall_sz + RPC_MAX_HEADER_WITH_AUTH)
+ return nfserr_toosmall;
+ if (ca->maxresp_sz < NFS4_dec_cb_recall_sz + RPC_MAX_REPHEADER_WITH_AUTH)
+ return nfserr_toosmall;
+ ca->maxresp_cached = 0;
+ if (ca->maxops < 2)
+ return nfserr_toosmall;
+
+ return nfs_ok;
+}
+
__be32
nfsd4_create_session(struct svc_rqst *rqstp,
struct nfsd4_compound_state *cstate,
@@ -1812,6 +1834,9 @@
status = check_forechannel_attrs(&cr_ses->fore_channel, nn);
if (status)
return status;
+ status = check_backchannel_attrs(&cr_ses->back_channel);
+ if (status)
+ return status;
status = nfserr_jukebox;
new = alloc_session(&cr_ses->fore_channel);
if (!new)