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>

diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c
index 9166fcb66da219f4b9d2a8dc4445b5b945627b16..89fc160fd5b071af390ee4aea4590e929c43acee 100644 (file)
--- 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);