knfsd: nfsd4: secinfo handling without secinfo= option

We could return some sort of error in the case where someone asks for secinfo
on an export without the secinfo= option set--that'd be no worse than what
we've been doing.  But it's not really correct.  So, hack up an approximate
secinfo response in that case--it may not be complete, but it'll tell the
client at least one acceptable security flavor.

Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 27 insertions, 3 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 864498f8f2d9..b3d55c6747fd 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -57,6 +57,7 @@
 #include <linux/nfs4.h>
 #include <linux/nfs4_acl.h>
 #include <linux/sunrpc/gss_api.h>
+#include <linux/sunrpc/svcauth_gss.h>
 
 #define NFSDDBG_FACILITY                NFSDDBG_XDR
 
@@ -2454,15 +2455,38 @@ nfsd4_encode_secinfo(struct nfsd4_compoundres *resp, int nfserr,
 {
         int i = 0;
         struct svc_export *exp = secinfo->si_exp;
+        u32 nflavs;
+        struct exp_flavor_info *flavs;
+        struct exp_flavor_info def_flavs[2];
         ENCODE_HEAD;
 
         if (nfserr)
                 goto out;
+        if (exp->ex_nflavors) {
+                flavs = exp->ex_flavors;
+                nflavs = exp->ex_nflavors;
+        } else { /* Handling of some defaults in absence of real secinfo: */
+                flavs = def_flavs;
+                if (exp->ex_client->flavour->flavour == RPC_AUTH_UNIX) {
+                        nflavs = 2;
+                        flavs[0].pseudoflavor = RPC_AUTH_UNIX;
+                        flavs[1].pseudoflavor = RPC_AUTH_NULL;
+                } else if (exp->ex_client->flavour->flavour == RPC_AUTH_GSS) {
+                        nflavs = 1;
+                        flavs[0].pseudoflavor
+                                        = svcauth_gss_flavor(exp->ex_client);
+                } else {
+                        nflavs = 1;
+                        flavs[0].pseudoflavor
+                                        = exp->ex_client->flavour->flavour;
+                }
+        }
+
         RESERVE_SPACE(4);
-        WRITE32(exp->ex_nflavors);
+        WRITE32(nflavs);
         ADJUST_ARGS();
-        for (i = 0; i < exp->ex_nflavors; i++) {
-                u32 flav = exp->ex_flavors[i].pseudoflavor;
+        for (i = 0; i < nflavs; i++) {
+                u32 flav = flavs[i].pseudoflavor;
                 struct gss_api_mech *gm = gss_mech_get_by_pseudoflavor(flav);
 
                 if (gm) {