On Wed, Dec 03, 2014 at 08:59:01PM +0100, Stephan Mueller wrote:

+static int rng_recvmsg(struct kiocb *unused, struct socket *sock,
+		       struct msghdr *msg, size_t len, int flags)
+{
+	struct sock *sk = sock->sk;
+	struct alg_sock *ask = alg_sk(sk);
+	struct rng_ctx *ctx = ask->private;
+	int err = -EFAULT;
+
+	if (len == 0)
+		return 0;
+	if (len > MAXSIZE)
+		len = MAXSIZE;
+
+	lock_sock(sk);

This lock simply protects ctx->result.  Since you're using a
tiny buffer why not just put it on the stack?

+		u8 *buf = kmalloc(seedsize, GFP_KERNEL);
+		if (!buf)
+			goto err;
+		get_random_bytes(buf, seedsize);
+		ret = crypto_rng_reset(private, buf, len);

I think you should leave the seeding and the seed to the user.
Perhaps do it through setsockopt (on the parent socket).

Cheers,
-- 
Email: Herbert Xu [off-list ref]
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