svcgss: move init code into separate function

We've let svcauth_gss_accept() get much too long and hairy.  The
RPC_GSS_PROC_INIT and RPC_GSS_PROC_CONTINUE_INIT cases share very little
with the other cases, so it's very natural to split them off into a
separate function.

This will also nicely isolate the piece of code we need to parametrize
to authenticating gss-protected NFSv4 callbacks on behalf of the NFS
client.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Acked-by: Neil Brown <neilb@suse.de>

1 files changed, 77 insertions, 67 deletions

diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index 7da7050f06c3..73940df6c460 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -631,7 +631,8 @@ svc_safe_putnetobj(struct kvec *resv, struct xdr_netobj *o)
         return 0;
 }
 
-/* Verify the checksum on the header and return SVC_OK on success.
+/*
+ * Verify the checksum on the header and return SVC_OK on success.
  * Otherwise, return SVC_DROP (in the case of a bad sequence number)
  * or return SVC_DENIED and indicate error in authp.
  */
@@ -961,6 +962,78 @@ gss_write_init_verf(struct svc_rqst *rqstp, struct rsi *rsip)
 }
 
 /*
+ * Having read the cred already and found we're in the context
+ * initiation case, read the verifier and initiate (or check the results
+ * of) upcalls to userspace for help with context initiation.  If
+ * the upcall results are available, write the verifier and result.
+ * Otherwise, drop the request pending an answer to the upcall.
+ */
+static int svcauth_gss_handle_init(struct svc_rqst *rqstp,
+                        struct rpc_gss_wire_cred *gc, __be32 *authp)
+{
+        struct kvec *argv = &rqstp->rq_arg.head[0];
+        struct kvec *resv = &rqstp->rq_res.head[0];
+        struct xdr_netobj tmpobj;
+        struct rsi *rsip, rsikey;
+
+        /* Read the verifier; should be NULL: */
+        *authp = rpc_autherr_badverf;
+        if (argv->iov_len < 2 * 4)
+                return SVC_DENIED;
+        if (svc_getnl(argv) != RPC_AUTH_NULL)
+                return SVC_DENIED;
+        if (svc_getnl(argv) != 0)
+                return SVC_DENIED;
+
+        /* Martial context handle and token for upcall: */
+        *authp = rpc_autherr_badcred;
+        if (gc->gc_proc == RPC_GSS_PROC_INIT && gc->gc_ctx.len != 0)
+                return SVC_DENIED;
+        memset(&rsikey, 0, sizeof(rsikey));
+        if (dup_netobj(&rsikey.in_handle, &gc->gc_ctx))
+                return SVC_DROP;
+        *authp = rpc_autherr_badverf;
+        if (svc_safe_getnetobj(argv, &tmpobj)) {
+                kfree(rsikey.in_handle.data);
+                return SVC_DENIED;
+        }
+        if (dup_netobj(&rsikey.in_token, &tmpobj)) {
+                kfree(rsikey.in_handle.data);
+                return SVC_DROP;
+        }
+
+        /* Perform upcall, or find upcall result: */
+        rsip = rsi_lookup(&rsikey);
+        rsi_free(&rsikey);
+        if (!rsip)
+                return SVC_DROP;
+        switch (cache_check(&rsi_cache, &rsip->h, &rqstp->rq_chandle)) {
+        case -EAGAIN:
+        case -ETIMEDOUT:
+        case -ENOENT:
+                /* No upcall result: */
+                return SVC_DROP;
+        case 0:
+                /* Got an answer to the upcall; use it: */
+                if (gss_write_init_verf(rqstp, rsip))
+                        return SVC_DROP;
+                if (resv->iov_len + 4 > PAGE_SIZE)
+                        return SVC_DROP;
+                svc_putnl(resv, RPC_SUCCESS);
+                if (svc_safe_putnetobj(resv, &rsip->out_handle))
+                        return SVC_DROP;
+                if (resv->iov_len + 3 * 4 > PAGE_SIZE)
+                        return SVC_DROP;
+                svc_putnl(resv, rsip->major_status);
+                svc_putnl(resv, rsip->minor_status);
+                svc_putnl(resv, GSS_SEQ_WIN);
+                if (svc_safe_putnetobj(resv, &rsip->out_token))
+                        return SVC_DROP;
+        }
+        return SVC_COMPLETE;
+}
+
+/*
  * Accept an rpcsec packet.
  * If context establishment, punt to user space
  * If data exchange, verify/decrypt
@@ -974,11 +1047,9 @@ svcauth_gss_accept(struct svc_rqst *rqstp, __be32 *authp)
         struct kvec     *argv = &rqstp->rq_arg.head[0];
         struct kvec     *resv = &rqstp->rq_res.head[0];
         u32             crlen;
-        struct xdr_netobj tmpobj;
         struct gss_svc_data *svcdata = rqstp->rq_auth_data;
         struct rpc_gss_wire_cred *gc;
         struct rsc      *rsci = NULL;
-        struct rsi      *rsip, rsikey;
         __be32          *rpcstart;
         __be32          *reject_stat = resv->iov_base + resv->iov_len;
         int             ret;
@@ -1023,30 +1094,14 @@ svcauth_gss_accept(struct svc_rqst *rqstp, __be32 *authp)
         if ((gc->gc_proc != RPC_GSS_PROC_DATA) && (rqstp->rq_proc != 0))
                 goto auth_err;
 
-        /*
-         * We've successfully parsed the credential. Let's check out the
-         * verifier.  An AUTH_NULL verifier is allowed (and required) for
-         * INIT and CONTINUE_INIT requests. AUTH_RPCSEC_GSS is required for
-         * PROC_DATA and PROC_DESTROY.
-         *
-         * AUTH_NULL verifier is 0 (AUTH_NULL), 0 (length).
-         * AUTH_RPCSEC_GSS verifier is:
-         *   6 (AUTH_RPCSEC_GSS), length, checksum.
-         * checksum is calculated over rpcheader from xid up to here.
-         */
         *authp = rpc_autherr_badverf;
         switch (gc->gc_proc) {
         case RPC_GSS_PROC_INIT:
         case RPC_GSS_PROC_CONTINUE_INIT:
-                if (argv->iov_len < 2 * 4)
-                        goto auth_err;
-                if (svc_getnl(argv) != RPC_AUTH_NULL)
-                        goto auth_err;
-                if (svc_getnl(argv) != 0)
-                        goto auth_err;
-                break;
+                return svcauth_gss_handle_init(rqstp, gc, authp);
         case RPC_GSS_PROC_DATA:
         case RPC_GSS_PROC_DESTROY:
+                /* Look up the context, and check the verifier: */
                 *authp = rpcsec_gsserr_credproblem;
                 rsci = gss_svc_searchbyctx(&gc->gc_ctx);
                 if (!rsci)
@@ -1067,51 +1122,6 @@ svcauth_gss_accept(struct svc_rqst *rqstp, __be32 *authp)
 
         /* now act upon the command: */
         switch (gc->gc_proc) {
-        case RPC_GSS_PROC_INIT:
-        case RPC_GSS_PROC_CONTINUE_INIT:
-                *authp = rpc_autherr_badcred;
-                if (gc->gc_proc == RPC_GSS_PROC_INIT && gc->gc_ctx.len != 0)
-                        goto auth_err;
-                memset(&rsikey, 0, sizeof(rsikey));
-                if (dup_netobj(&rsikey.in_handle, &gc->gc_ctx))
-                        goto drop;
-                *authp = rpc_autherr_badverf;
-                if (svc_safe_getnetobj(argv, &tmpobj)) {
-                        kfree(rsikey.in_handle.data);
-                        goto auth_err;
-                }
-                if (dup_netobj(&rsikey.in_token, &tmpobj)) {
-                        kfree(rsikey.in_handle.data);
-                        goto drop;
-                }
-
-                rsip = rsi_lookup(&rsikey);
-                rsi_free(&rsikey);
-                if (!rsip) {
-                        goto drop;
-                }
-                switch(cache_check(&rsi_cache, &rsip->h, &rqstp->rq_chandle)) {
-                case -EAGAIN:
-                case -ETIMEDOUT:
-                case -ENOENT:
-                        goto drop;
-                case 0:
-                        if (gss_write_init_verf(rqstp, rsip))
-                                goto drop;
-                        if (resv->iov_len + 4 > PAGE_SIZE)
-                                goto drop;
-                        svc_putnl(resv, RPC_SUCCESS);
-                        if (svc_safe_putnetobj(resv, &rsip->out_handle))
-                                goto drop;
-                        if (resv->iov_len + 3 * 4 > PAGE_SIZE)
-                                goto drop;
-                        svc_putnl(resv, rsip->major_status);
-                        svc_putnl(resv, rsip->minor_status);
-                        svc_putnl(resv, GSS_SEQ_WIN);
-                        if (svc_safe_putnetobj(resv, &rsip->out_token))
-                                goto drop;
-                }
-                goto complete;
         case RPC_GSS_PROC_DESTROY:
                 if (gss_write_verf(rqstp, rsci->mechctx, gc->gc_seq))
                         goto auth_err;
@@ -1158,7 +1168,7 @@ svcauth_gss_accept(struct svc_rqst *rqstp, __be32 *authp)
                 goto out;
         }
 auth_err:
-        /* Restore write pointer to original value: */
+        /* Restore write pointer to its original value: */
         xdr_ressize_check(rqstp, reject_stat);
         ret = SVC_DENIED;
         goto out;