auth_gss.c

linux-2.6.15.6

	struct rpc_cred *cred = task->tk_msg.rpc_cred;
	struct gss_auth *gss_auth = container_of(task->tk_client->cl_auth,
			struct gss_auth, rpc_auth);
	struct gss_cred *gss_cred = container_of(cred,
			struct gss_cred, gc_base);
	struct gss_upcall_msg *gss_msg;
	int err = 0;

	dprintk("RPC: %4u gss_refresh_upcall for uid %u\n", task->tk_pid, cred->cr_uid);
	gss_msg = gss_setup_upcall(task->tk_client, gss_auth, cred);
	if (IS_ERR(gss_msg)) {
		err = PTR_ERR(gss_msg);
		goto out;
	}
	spin_lock(&gss_auth->lock);
	if (gss_cred->gc_upcall != NULL)
		rpc_sleep_on(&gss_cred->gc_upcall->rpc_waitqueue, task, NULL, NULL);
	else if (gss_msg->ctx == NULL && gss_msg->msg.errno >= 0) {
		task->tk_timeout = 0;
		gss_cred->gc_upcall = gss_msg;
		/* gss_upcall_callback will release the reference to gss_upcall_msg */
		atomic_inc(&gss_msg->count);
		rpc_sleep_on(&gss_msg->rpc_waitqueue, task, gss_upcall_callback, NULL);
	} else
		err = gss_msg->msg.errno;
	spin_unlock(&gss_auth->lock);
	gss_release_msg(gss_msg);
out:
	dprintk("RPC: %4u gss_refresh_upcall for uid %u result %d\n", task->tk_pid,
			cred->cr_uid, err);
	return err;
}

static inline int
gss_create_upcall(struct gss_auth *gss_auth, struct gss_cred *gss_cred)
{
	struct rpc_cred *cred = &gss_cred->gc_base;
	struct gss_upcall_msg *gss_msg;
	DEFINE_WAIT(wait);
	int err = 0;

	dprintk("RPC: gss_upcall for uid %u\n", cred->cr_uid);
	gss_msg = gss_setup_upcall(gss_auth->client, gss_auth, cred);
	if (IS_ERR(gss_msg)) {
		err = PTR_ERR(gss_msg);
		goto out;
	}
	for (;;) {
		prepare_to_wait(&gss_msg->waitqueue, &wait, TASK_INTERRUPTIBLE);
		spin_lock(&gss_auth->lock);
		if (gss_msg->ctx != NULL || gss_msg->msg.errno < 0) {
			spin_unlock(&gss_auth->lock);
			break;
		}
		spin_unlock(&gss_auth->lock);
		if (signalled()) {
			err = -ERESTARTSYS;
			goto out_intr;
		}
		schedule();
	}
	if (gss_msg->ctx)
		gss_cred_set_ctx(cred, gss_get_ctx(gss_msg->ctx));
	else
		err = gss_msg->msg.errno;
out_intr:
	finish_wait(&gss_msg->waitqueue, &wait);
	gss_release_msg(gss_msg);
out:
	dprintk("RPC: gss_create_upcall for uid %u result %d\n", cred->cr_uid, err);
	return err;
}

static ssize_t
gss_pipe_upcall(struct file *filp, struct rpc_pipe_msg *msg,
		char __user *dst, size_t buflen)
{
	char *data = (char *)msg->data + msg->copied;
	ssize_t mlen = msg->len;
	ssize_t left;

	if (mlen > buflen)
		mlen = buflen;
	left = copy_to_user(dst, data, mlen);
	if (left < 0) {
		msg->errno = left;
		return left;
	}
	mlen -= left;
	msg->copied += mlen;
	msg->errno = 0;
	return mlen;
}

#define MSG_BUF_MAXSIZE 1024

static ssize_t
gss_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
{
	const void *p, *end;
	void *buf;
	struct rpc_clnt *clnt;
	struct gss_auth *gss_auth;
	struct rpc_cred *cred;
	struct gss_upcall_msg *gss_msg;
	struct gss_cl_ctx *ctx;
	uid_t uid;
	int err = -EFBIG;

	if (mlen > MSG_BUF_MAXSIZE)
		goto out;
	err = -ENOMEM;
	buf = kmalloc(mlen, GFP_KERNEL);
	if (!buf)
		goto out;

	clnt = RPC_I(filp->f_dentry->d_inode)->private;
	err = -EFAULT;
	if (copy_from_user(buf, src, mlen))
		goto err;

	end = (const void *)((char *)buf + mlen);
	p = simple_get_bytes(buf, end, &uid, sizeof(uid));
	if (IS_ERR(p)) {
		err = PTR_ERR(p);
		goto err;
	}

	err = -ENOMEM;
	ctx = gss_alloc_context();
	if (ctx == NULL)
		goto err;
	err = 0;
	gss_auth = container_of(clnt->cl_auth, struct gss_auth, rpc_auth);
	p = gss_fill_context(p, end, ctx, gss_auth->mech);
	if (IS_ERR(p)) {
		err = PTR_ERR(p);
		if (err != -EACCES)
			goto err_put_ctx;
	}
	spin_lock(&gss_auth->lock);
	gss_msg = __gss_find_upcall(gss_auth, uid);
	if (gss_msg) {
		if (err == 0 && gss_msg->ctx == NULL)
			gss_msg->ctx = gss_get_ctx(ctx);
		gss_msg->msg.errno = err;
		__gss_unhash_msg(gss_msg);
		spin_unlock(&gss_auth->lock);
		gss_release_msg(gss_msg);
	} else {
		struct auth_cred acred = { .uid = uid };
		spin_unlock(&gss_auth->lock);
		cred = rpcauth_lookup_credcache(clnt->cl_auth, &acred, 0);
		if (IS_ERR(cred)) {
			err = PTR_ERR(cred);
			goto err_put_ctx;
		}
		gss_cred_set_ctx(cred, gss_get_ctx(ctx));
	}
	gss_put_ctx(ctx);
	kfree(buf);
	dprintk("RPC:      gss_pipe_downcall returning length %Zu\n", mlen);
	return mlen;
err_put_ctx:
	gss_put_ctx(ctx);
err:
	kfree(buf);
out:
	dprintk("RPC:      gss_pipe_downcall returning %d\n", err);
	return err;
}

static void
gss_pipe_release(struct inode *inode)
{
	struct rpc_inode *rpci = RPC_I(inode);
	struct rpc_clnt *clnt;
	struct rpc_auth *auth;
	struct gss_auth *gss_auth;

	clnt = rpci->private;
	auth = clnt->cl_auth;
	gss_auth = container_of(auth, struct gss_auth, rpc_auth);
	spin_lock(&gss_auth->lock);
	while (!list_empty(&gss_auth->upcalls)) {
		struct gss_upcall_msg *gss_msg;

		gss_msg = list_entry(gss_auth->upcalls.next,
				struct gss_upcall_msg, list);
		gss_msg->msg.errno = -EPIPE;
		atomic_inc(&gss_msg->count);
		__gss_unhash_msg(gss_msg);
		spin_unlock(&gss_auth->lock);
		gss_release_msg(gss_msg);
		spin_lock(&gss_auth->lock);
	}
	spin_unlock(&gss_auth->lock);
}

static void
gss_pipe_destroy_msg(struct rpc_pipe_msg *msg)
{
	struct gss_upcall_msg *gss_msg = container_of(msg, struct gss_upcall_msg, msg);
	static unsigned long ratelimit;

	if (msg->errno < 0) {
		dprintk("RPC:      gss_pipe_destroy_msg releasing msg %p\n",
				gss_msg);
		atomic_inc(&gss_msg->count);
		gss_unhash_msg(gss_msg);
		if (msg->errno == -ETIMEDOUT) {
			unsigned long now = jiffies;
			if (time_after(now, ratelimit)) {
				printk(KERN_WARNING "RPC: AUTH_GSS upcall timed out.\n"
						    "Please check user daemon is running!\n");
				ratelimit = now + 15*HZ;
			}
		}
		gss_release_msg(gss_msg);
	}
}

/* 
 * NOTE: we have the opportunity to use different 
 * parameters based on the input flavor (which must be a pseudoflavor)
 */
static struct rpc_auth *
gss_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
{
	struct gss_auth *gss_auth;
	struct rpc_auth * auth;
	int err = -ENOMEM; /* XXX? */

	dprintk("RPC:      creating GSS authenticator for client %p\n",clnt);

	if (!try_module_get(THIS_MODULE))
		return ERR_PTR(err);
	if (!(gss_auth = kmalloc(sizeof(*gss_auth), GFP_KERNEL)))
		goto out_dec;
	gss_auth->client = clnt;
	err = -EINVAL;
	gss_auth->mech = gss_mech_get_by_pseudoflavor(flavor);
	if (!gss_auth->mech) {
		printk(KERN_WARNING "%s: Pseudoflavor %d not found!",
				__FUNCTION__, flavor);
		goto err_free;
	}
	gss_auth->service = gss_pseudoflavor_to_service(gss_auth->mech, flavor);
	if (gss_auth->service == 0)
		goto err_put_mech;
	INIT_LIST_HEAD(&gss_auth->upcalls);
	spin_lock_init(&gss_auth->lock);
	auth = &gss_auth->rpc_auth;
	auth->au_cslack = GSS_CRED_SLACK >> 2;
	auth->au_rslack = GSS_VERF_SLACK >> 2;
	auth->au_ops = &authgss_ops;
	auth->au_flavor = flavor;
	atomic_set(&auth->au_count, 1);

	err = rpcauth_init_credcache(auth, GSS_CRED_EXPIRE);
	if (err)
		goto err_put_mech;

	snprintf(gss_auth->path, sizeof(gss_auth->path), "%s/%s",
			clnt->cl_pathname,
			gss_auth->mech->gm_name);
	gss_auth->dentry = rpc_mkpipe(gss_auth->path, clnt, &gss_upcall_ops, RPC_PIPE_WAIT_FOR_OPEN);
	if (IS_ERR(gss_auth->dentry)) {
		err = PTR_ERR(gss_auth->dentry);
		goto err_put_mech;
	}

	return auth;
err_put_mech:
	gss_mech_put(gss_auth->mech);
err_free:
	kfree(gss_auth);
out_dec:
	module_put(THIS_MODULE);
	return ERR_PTR(err);
}

static void
gss_destroy(struct rpc_auth *auth)
{
	struct gss_auth *gss_auth;

	dprintk("RPC:      destroying GSS authenticator %p flavor %d\n",
		auth, auth->au_flavor);

	gss_auth = container_of(auth, struct gss_auth, rpc_auth);
	rpc_unlink(gss_auth->path);
	gss_mech_put(gss_auth->mech);

	rpcauth_free_credcache(auth);
	kfree(gss_auth);
	module_put(THIS_MODULE);
}

/* gss_destroy_cred (and gss_destroy_ctx) are used to clean up after failure
 * to create a new cred or context, so they check that things have been
 * allocated before freeing them. */
static void
gss_destroy_ctx(struct gss_cl_ctx *ctx)
{
	dprintk("RPC:      gss_destroy_ctx\n");

	if (ctx->gc_gss_ctx)
		gss_delete_sec_context(&ctx->gc_gss_ctx);

	kfree(ctx->gc_wire_ctx.data);
	kfree(ctx);
}

static void
gss_destroy_cred(struct rpc_cred *rc)
{
	struct gss_cred *cred = container_of(rc, struct gss_cred, gc_base);

	dprintk("RPC:      gss_destroy_cred \n");

	if (cred->gc_ctx)
		gss_put_ctx(cred->gc_ctx);
	kfree(cred);
}

/*
 * Lookup RPCSEC_GSS cred for the current process
 */
static struct rpc_cred *
gss_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int taskflags)
{
	return rpcauth_lookup_credcache(auth, acred, taskflags);
}

static struct rpc_cred *
gss_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int taskflags)
{
	struct gss_auth *gss_auth = container_of(auth, struct gss_auth, rpc_auth);
	struct gss_cred	*cred = NULL;
	int err = -ENOMEM;

	dprintk("RPC:      gss_create_cred for uid %d, flavor %d\n",
		acred->uid, auth->au_flavor);

	if (!(cred = kmalloc(sizeof(*cred), GFP_KERNEL)))
		goto out_err;

	memset(cred, 0, sizeof(*cred));
	atomic_set(&cred->gc_count, 1);
	cred->gc_uid = acred->uid;
	/*
	 * Note: in order to force a call to call_refresh(), we deliberately
	 * fail to flag the credential as RPCAUTH_CRED_UPTODATE.
	 */
	cred->gc_flags = 0;
	cred->gc_base.cr_ops = &gss_credops;
	cred->gc_service = gss_auth->service;
	do {
		err = gss_create_upcall(gss_auth, cred);
	} while (err == -EAGAIN);
	if (err < 0)
		goto out_err;

	return &cred->gc_base;

out_err:
	dprintk("RPC:      gss_create_cred failed with error %d\n", err);
	if (cred) gss_destroy_cred(&cred->gc_base);
	return ERR_PTR(err);
}

static int
gss_match(struct auth_cred *acred, struct rpc_cred *rc, int taskflags)
{
	struct gss_cred *gss_cred = container_of(rc, struct gss_cred, gc_base);

	/* Don't match with creds that have expired. */
	if (gss_cred->gc_ctx && time_after(jiffies, gss_cred->gc_ctx->gc_expiry))
		return 0;
	return (rc->cr_uid == acred->uid);
}

/*
* Marshal credentials.
* Maybe we should keep a cached credential for performance reasons.
*/
static u32 *
gss_marshal(struct rpc_task *task, u32 *p)
{
	struct rpc_cred *cred = task->tk_msg.rpc_cred;
	struct gss_cred	*gss_cred = container_of(cred, struct gss_cred,
						 gc_base);
	struct gss_cl_ctx	*ctx = gss_cred_get_ctx(cred);
	u32		*cred_len;
	struct rpc_rqst *req = task->tk_rqstp;
	u32             maj_stat = 0;
	struct xdr_netobj mic;
	struct kvec	iov;
	struct xdr_buf	verf_buf;

	dprintk("RPC: %4u gss_marshal\n", task->tk_pid);

	*p++ = htonl(RPC_AUTH_GSS);
	cred_len = p++;

	spin_lock(&ctx->gc_seq_lock);
	req->rq_seqno = ctx->gc_seq++;
	spin_unlock(&ctx->gc_seq_lock);

	*p++ = htonl((u32) RPC_GSS_VERSION);
	*p++ = htonl((u32) ctx->gc_proc);
	*p++ = htonl((u32) req->rq_seqno);
	*p++ = htonl((u32) gss_cred->gc_service);
	p = xdr_encode_netobj(p, &ctx->gc_wire_ctx);
	*cred_len = htonl((p - (cred_len + 1)) << 2);

	/* We compute the checksum for the verifier over the xdr-encoded bytes
	 * starting with the xid and ending at the end of the credential: */
	iov.iov_base = xprt_skip_transport_header(task->tk_xprt,
					req->rq_snd_buf.head[0].iov_base);
	iov.iov_len = (u8 *)p - (u8 *)iov.iov_base;
	xdr_buf_from_iov(&iov, &verf_buf);

	/* set verifier flavor*/
	*p++ = htonl(RPC_AUTH_GSS);

	mic.data = (u8 *)(p + 1);
	maj_stat = gss_get_mic(ctx->gc_gss_ctx, &verf_buf, &mic);
	if (maj_stat == GSS_S_CONTEXT_EXPIRED) {