nfsd4: backchannel should use client-provided security flavor

For now this only adds support for AUTH_NULL.  (Previously we assumed
AUTH_UNIX.)  We'll also need AUTH_GSS, which is trickier.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

3 files changed, 13 insertions, 5 deletions

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index a1aa18db08fb..7bb187ac1492 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -692,7 +692,7 @@ static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *c
                 args.bc_xprt = conn->cb_xprt;
                 args.prognumber = clp->cl_cb_session->se_cb_prog;
                 args.protocol = XPRT_TRANSPORT_BC_TCP;
-                args.authflavor = RPC_AUTH_UNIX;
+                args.authflavor = ses->se_cb_sec.flavor;
         }
         /* Create RPC client */
         client = rpc_create(&args);
@@ -709,7 +709,6 @@ static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *c
         clp->cl_cb_client = client;
         clp->cl_cb_cred = cred;
         return 0;
-
 }
 
 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index d7e7c110246e..406d0c4620f6 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -425,7 +425,7 @@ nfsd4_decode_access(struct nfsd4_compoundargs *argp, struct nfsd4_access *access
 static __be32 nfsd4_decode_cb_sec(struct nfsd4_compoundargs *argp, struct nfsd4_cb_sec *cbs)
 {
         DECODE_HEAD;
-        u32 dummy;
+        u32 dummy, uid, gid;
         char *machine_name;
         int i;
         int nr_secflavs;
@@ -433,12 +433,15 @@ static __be32 nfsd4_decode_cb_sec(struct nfsd4_compoundargs *argp, struct nfsd4_
         /* callback_sec_params4 */
         READ_BUF(4);
         READ32(nr_secflavs);
+        cbs->flavor = (u32)(-1);
         for (i = 0; i < nr_secflavs; ++i) {
                 READ_BUF(4);
                 READ32(dummy);
                 switch (dummy) {
                 case RPC_AUTH_NULL:
                         /* Nothing to read */
+                        if (cbs->flavor == (u32)(-1))
+                                cbs->flavor = RPC_AUTH_NULL;
                         break;
                 case RPC_AUTH_UNIX:
                         READ_BUF(8);
@@ -452,13 +455,18 @@ static __be32 nfsd4_decode_cb_sec(struct nfsd4_compoundargs *argp, struct nfsd4_
 
                         /* uid, gid */
                         READ_BUF(8);
-                        READ32(cbs->uid);
-                        READ32(cbs->gid);
+                        READ32(uid);
+                        READ32(gid);
 
                         /* more gids */
                         READ_BUF(4);
                         READ32(dummy);
                         READ_BUF(dummy * 4);
+                        if (cbs->flavor == (u32)(-1)) {
+                                cbs->uid = uid;
+                                cbs->gid = gid;
+                                cbs->flavor = RPC_AUTH_UNIX;
+                        }
                         break;
                 case RPC_AUTH_GSS:
                         dprintk("RPC_AUTH_GSS callback secflavor "
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 0fd342a2174e..0498053b8f0e 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -151,6 +151,7 @@ struct nfsd4_channel_attrs {
 };
 
 struct nfsd4_cb_sec {
+        u32     flavor; /* (u32)(-1) used to mean "no valid flavor" */
         u32     uid;
         u32     gid;
 };