NFS: Fix a signed vs. unsigned secinfo bug

rpc_authflavor_t is cast from an unsigned int, but the
initial code tried to use it as a signed int.  I fix
this by passing an rpc_authflavor_t pointer around, and
returning signed integers from functions.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 25 insertions, 33 deletions

diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c
index 9166fcb66da2..89fc160fd5b0 100644
--- a/fs/nfs/namespace.c
+++ b/fs/nfs/namespace.c
@@ -148,67 +148,64 @@ static rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors,
         return pseudoflavor;
 }
 
-static rpc_authflavor_t nfs_negotiate_security(const struct dentry *parent, const struct dentry *dentry)
+static int nfs_negotiate_security(const struct dentry *parent,
+                                  const struct dentry *dentry,
+                                  rpc_authflavor_t *flavor)
 {
-        int status = 0;
         struct page *page;
         struct nfs4_secinfo_flavors *flavors;
         int (*secinfo)(struct inode *, const struct qstr *, struct nfs4_secinfo_flavors *);
-        rpc_authflavor_t flavor = RPC_AUTH_UNIX;
+        int ret = -EPERM;
 
         secinfo = NFS_PROTO(parent->d_inode)->secinfo;
         if (secinfo != NULL) {
                 page = alloc_page(GFP_KERNEL);
                 if (!page) {
-                        status = -ENOMEM;
+                        ret = -ENOMEM;
                         goto out;
                 }
                 flavors = page_address(page);
-                status = secinfo(parent->d_inode, &dentry->d_name, flavors);
-                flavor = nfs_find_best_sec(flavors, dentry->d_inode);
+                ret = secinfo(parent->d_inode, &dentry->d_name, flavors);
+                *flavor = nfs_find_best_sec(flavors, dentry->d_inode);
                 put_page(page);
         }
 
-        return flavor;
-
 out:
-        status = -ENOMEM;
-        return status;
+        return ret;
 }
 
-static rpc_authflavor_t nfs_lookup_with_sec(struct nfs_server *server, struct dentry *parent,
-                                     struct dentry *dentry, struct path *path,
-                                     struct nfs_fh *fh, struct nfs_fattr *fattr)
+static int nfs_lookup_with_sec(struct nfs_server *server, struct dentry *parent,
+                               struct dentry *dentry, struct path *path,
+                               struct nfs_fh *fh, struct nfs_fattr *fattr,
+                               rpc_authflavor_t *flavor)
 {
-        rpc_authflavor_t flavor;
         struct rpc_clnt *clone;
         struct rpc_auth *auth;
         int err;
 
-        flavor = nfs_negotiate_security(parent, path->dentry);
-        if (flavor < 0)
+        err = nfs_negotiate_security(parent, path->dentry, flavor);
+        if (err < 0)
                 goto out;
         clone  = rpc_clone_client(server->client);
-        auth   = rpcauth_create(flavor, clone);
+        auth   = rpcauth_create(*flavor, clone);
         if (!auth) {
-                flavor = -EIO;
+                err = -EIO;
                 goto out_shutdown;
         }
         err = server->nfs_client->rpc_ops->lookup(clone, parent->d_inode,
                                                   &path->dentry->d_name,
                                                   fh, fattr);
-        if (err < 0)
-                flavor = err;
 out_shutdown:
         rpc_shutdown_client(clone);
 out:
-        return flavor;
+        return err;
 }
 #else /* CONFIG_NFS_V4 */
-static inline rpc_authflavor_t nfs_lookup_with_sec(struct nfs_server *server,
-                                     struct dentry *parent, struct dentry *dentry,
-                                     struct path *path, struct nfs_fh *fh,
-                                     struct nfs_fattr *fattr)
+static inline int nfs_lookup_with_sec(struct nfs_server *server,
+                                      struct dentry *parent, struct dentry *dentry,
+                                      struct path *path, struct nfs_fh *fh,
+                                      struct nfs_fattr *fattr,
+                                      rpc_authflavor_t *flavor)
 {
         return -EPERM;
 }
@@ -234,7 +231,7 @@ struct vfsmount *nfs_d_automount(struct path *path)
         struct nfs_fh *fh = NULL;
         struct nfs_fattr *fattr = NULL;
         int err;
-        rpc_authflavor_t flavor = 1;
+        rpc_authflavor_t flavor = RPC_AUTH_UNIX;
 
         dprintk("--> nfs_d_automount()\n");
 
@@ -255,13 +252,8 @@ struct vfsmount *nfs_d_automount(struct path *path)
         err = server->nfs_client->rpc_ops->lookup(server->client, parent->d_inode,
                                                   &path->dentry->d_name,
                                                   fh, fattr);
-        if (err == -EPERM) {
-                flavor = nfs_lookup_with_sec(server, parent, path->dentry, path, fh, fattr);
-                if (flavor < 0)
-                        err = flavor;
-                else
-                        err = 0;
-        }
+        if (err == -EPERM && NFS_PROTO(parent->d_inode)->secinfo != NULL)
+                err = nfs_lookup_with_sec(server, parent, path->dentry, path, fh, fattr, &flavor);
         dput(parent);
         if (err != 0) {
                 mnt = ERR_PTR(err);