2 files changed, 36 insertions, 8 deletions

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index f7be7fabe62c..ec51936d2ce2 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -811,14 +811,15 @@ static inline void nfsd4_increment_op_stats(u32 opnum)
 
 typedef __be32(*nfsd4op_func)(struct svc_rqst *, struct nfsd4_compound_state *,
                               void *);
+enum nfsd4_op_flags {
+        ALLOWED_WITHOUT_FH = 1 << 0,    /* No current filehandle required */
+        ALLOWED_ON_ABSENT_FS = 2 << 0,  /* ops processed on absent fs */
+        ALLOWED_AS_FIRST_OP = 3 << 0,   /* ops reqired first in compound */
+};
 
 struct nfsd4_operation {
         nfsd4op_func op_func;
         u32 op_flags;
-/* Most ops require a valid current filehandle; a few don't: */
-#define ALLOWED_WITHOUT_FH 1
-/* GETATTR and ops not listed as returning NFS4ERR_MOVED: */
-#define ALLOWED_ON_ABSENT_FS 2
         char *op_name;
 };
 
@@ -827,6 +828,23 @@ static struct nfsd4_operation nfsd4_ops[];
 static const char *nfsd4_op_name(unsigned opnum);
 
 /*
+ * Enforce NFSv4.1 COMPOUND ordering rules.
+ *
+ * TODO:
+ * - enforce NFS4ERR_NOT_ONLY_OP,
+ * - DESTROY_SESSION MUST be the final operation in the COMPOUND request.
+ */
+static bool nfs41_op_ordering_ok(struct nfsd4_compoundargs *args)
+{
+        if (args->minorversion && args->opcnt > 0) {
+                struct nfsd4_op *op = &args->ops[0];
+                return (op->status == nfserr_op_illegal) ||
+                       (nfsd4_ops[op->opnum].op_flags & ALLOWED_AS_FIRST_OP);
+        }
+        return true;
+}
+
+/*
  * COMPOUND call.
  */
 static __be32
@@ -864,6 +882,12 @@ nfsd4_proc_compound(struct svc_rqst *rqstp,
         if (args->minorversion > NFSD_SUPPORTED_MINOR_VERSION)
                 goto out;
 
+        if (!nfs41_op_ordering_ok(args)) {
+                op = &args->ops[0];
+                op->status = nfserr_sequence_pos;
+                goto encode_op;
+        }
+
         status = nfs_ok;
         while (!status && resp->opcnt < args->opcnt) {
                 op = &args->ops[resp->opcnt++];
@@ -1105,22 +1129,22 @@ static struct nfsd4_operation nfsd4_ops[] = {
         /* NFSv4.1 operations */
         [OP_EXCHANGE_ID] = {
                 .op_func = (nfsd4op_func)nfsd4_exchange_id,
-                .op_flags = ALLOWED_WITHOUT_FH,
+                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP,
                 .op_name = "OP_EXCHANGE_ID",
         },
         [OP_CREATE_SESSION] = {
                 .op_func = (nfsd4op_func)nfsd4_create_session,
-                .op_flags = ALLOWED_WITHOUT_FH,
+                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP,
                 .op_name = "OP_CREATE_SESSION",
         },
         [OP_DESTROY_SESSION] = {
                 .op_func = (nfsd4op_func)nfsd4_destroy_session,
-                .op_flags = ALLOWED_WITHOUT_FH,
+                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP,
                 .op_name = "OP_DESTROY_SESSION",
         },
         [OP_SEQUENCE] = {
                 .op_func = (nfsd4op_func)nfsd4_sequence,
-                .op_flags = ALLOWED_WITHOUT_FH,
+                .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP,
                 .op_name = "OP_SEQUENCE",
         },
 };
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 24b6e0593184..9243dca3576c 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1047,10 +1047,14 @@ nfsd4_sequence(struct svc_rqst *rqstp,
                struct nfsd4_compound_state *cstate,
                struct nfsd4_sequence *seq)
 {
+        struct nfsd4_compoundres *resp = rqstp->rq_resp;
         struct nfsd4_session *session;
         struct nfsd4_slot *slot;
         int status;
 
+        if (resp->opcnt != 1)
+                return nfserr_sequence_pos;
+
         spin_lock(&sessionid_lock);
         status = nfserr_badsession;
         session = find_in_sessionid_hashtbl(&seq->sessionid);