sunrpc: Update gss uid to security context mapping.

- Use from_kuid when generating the on the wire uid values.
- Use make_kuid when reading on the wire values.

In gss_encode_v0_msg, since the uid in gss_upcall_msg is now a kuid_t
generate the necessary uid_t value on the stack copy it into
gss_msg->databuf where it can safely live until the message is no
longer needed.

Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index afbbcfb..a360067 100644 (file)
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -395,8 +395,11 @@ gss_upcall_callback(struct rpc_task *task)
 
 static void gss_encode_v0_msg(struct gss_upcall_msg *gss_msg)
 {
-       gss_msg->msg.data = &gss_msg->uid;
-       gss_msg->msg.len = sizeof(gss_msg->uid);
+       uid_t uid = from_kuid(&init_user_ns, gss_msg->uid);
+       memcpy(gss_msg->databuf, &uid, sizeof(uid));
+       gss_msg->msg.data = gss_msg->databuf;
+       gss_msg->msg.len = sizeof(uid);
+       BUG_ON(sizeof(uid) > UPCALL_BUF_LEN);
 }
 
 static void gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
@@ -409,7 +412,7 @@ static void gss_encode_v1_msg(struct gss_upcall_msg *gss_msg,
 
        gss_msg->msg.len = sprintf(gss_msg->databuf, "mech=%s uid=%d ",
                                   mech->gm_name,
-                                  gss_msg->uid);
+                                  from_kuid(&init_user_ns, gss_msg->uid));
        p += gss_msg->msg.len;
        if (clnt->cl_principal) {
                len = sprintf(p, "target=%s ", clnt->cl_principal);
@@ -620,7 +623,8 @@ gss_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
        struct gss_upcall_msg *gss_msg;
        struct rpc_pipe *pipe = RPC_I(filp->f_dentry->d_inode)->pipe;
        struct gss_cl_ctx *ctx;
-       uid_t uid;
+       uid_t id;
+       kuid_t uid;
        ssize_t err = -EFBIG;
 
        if (mlen > MSG_BUF_MAXSIZE)
@@ -635,12 +639,18 @@ gss_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
                goto err;
 
        end = (const void *)((char *)buf + mlen);
-       p = simple_get_bytes(buf, end, &uid, sizeof(uid));
+       p = simple_get_bytes(buf, end, &id, sizeof(id));
        if (IS_ERR(p)) {
                err = PTR_ERR(p);
                goto err;
        }
 
+       uid = make_kuid(&init_user_ns, id);
+       if (!uid_valid(uid)) {
+               err = -EINVAL;
+               goto err;
+       }
+
        err = -ENOMEM;
        ctx = gss_alloc_context();
        if (ctx == NULL)