Am Montag, 22. Dezember 2014, 22:23:41 schrieb Herbert Xu:

Hi Herbert,

On Sun, Dec 07, 2014 at 11:22:30PM +0100, Stephan Mueller wrote:

quoted

+static inline bool aead_sufficient_data(struct aead_ctx *ctx)
+{
+	unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx-

aead_req));

quoted

+
+	return (ctx->used >= (ctx->aead_assoclen + ctx->enc ? : as ));

Is this supposed to be

	return (ctx->used >= (ctx->aead_assoclen + (ctx->enc ?: as)));

Thanks, will be fixed in the next iteration

quoted

+static int aead_recvmsg(struct kiocb *unused, struct socket *sock,
+			    struct msghdr *msg, size_t ignored, int flags)
+{

...

quoted

+	err = -ENOMEM;
+	if (!aead_sufficient_data(ctx))
+		goto unlock;

You should just block if there is insufficient input.

I do not concur here due to the following:

- the check aead_readable() immediately before this check implements the 
blocking if we do not have sufficient data *and* more data is to be expected

- this very check for aead_sufficient_data() comes into play if the caller 
does not have more data (i.e. ctx->more is zero). In this case, more data is 
not to be expected and we cannot wait as this would be a deadlock in user 
space.

-- 
Ciao
Stephan