nfsd4: fix oops on secinfo_no_name result encoding

The secinfo_no_name code oopses on encoding with

	BUG: unable to handle kernel NULL pointer dereference at 00000044
	IP: [<e2bd239a>] nfsd4_encode_secinfo+0x1c/0x1c1 [nfsd]

We should implement a nfsd4_encode_secinfo_no_name() instead using
nfsd4_encode_secinfo().

Signed-off-by: Mi Jinlong <mijinlong@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 17 insertions, 4 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index b543b2410b54..437b4623cb02 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2845,11 +2845,10 @@ nfsd4_encode_rename(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_
 }
 
 static __be32
-nfsd4_encode_secinfo(struct nfsd4_compoundres *resp, __be32 nfserr,
-                     struct nfsd4_secinfo *secinfo)
+nfsd4_do_encode_secinfo(struct nfsd4_compoundres *resp,
+                         __be32 nfserr,struct svc_export *exp)
 {
         int i = 0;
-        struct svc_export *exp = secinfo->si_exp;
         u32 nflavs;
         struct exp_flavor_info *flavs;
         struct exp_flavor_info def_flavs[2];
@@ -2911,6 +2910,20 @@ out:
         return nfserr;
 }
 
+static __be32
+nfsd4_encode_secinfo(struct nfsd4_compoundres *resp, __be32 nfserr,
+                     struct nfsd4_secinfo *secinfo)
+{
+        return nfsd4_do_encode_secinfo(resp, nfserr, secinfo->si_exp);
+}
+
+static __be32
+nfsd4_encode_secinfo_no_name(struct nfsd4_compoundres *resp, __be32 nfserr,
+                     struct nfsd4_secinfo_no_name *secinfo)
+{
+        return nfsd4_do_encode_secinfo(resp, nfserr, secinfo->sin_exp);
+}
+
 /*
  * The SETATTR encode routine is special -- it always encodes a bitmap,
  * regardless of the error status.
@@ -3173,7 +3186,7 @@ static nfsd4_enc nfsd4_enc_ops[] = {
         [OP_LAYOUTCOMMIT]       = (nfsd4_enc)nfsd4_encode_noop,
         [OP_LAYOUTGET]          = (nfsd4_enc)nfsd4_encode_noop,
         [OP_LAYOUTRETURN]       = (nfsd4_enc)nfsd4_encode_noop,
-        [OP_SECINFO_NO_NAME]    = (nfsd4_enc)nfsd4_encode_secinfo,
+        [OP_SECINFO_NO_NAME]    = (nfsd4_enc)nfsd4_encode_secinfo_no_name,
         [OP_SEQUENCE]           = (nfsd4_enc)nfsd4_encode_sequence,
         [OP_SET_SSV]            = (nfsd4_enc)nfsd4_encode_noop,
         [OP_TEST_STATEID]       = (nfsd4_enc)nfsd4_encode_noop,