Commit 1e104f9a authored Nov 27, 2014 by Herbert Xu

crypto: algif_skcipher - Fixed blocking recvmsg



As most (all?) users of algif_skcipher are single-threaded and
therefore always write before reading from an algif_skcipher
socket, they never block and exercise that code-path.

It turns out that code path doesn't even work because we never
reload ctx->used after waking up so we never even see the new
data and immediately return an error (and a loud WARN_ON).

This patch fixes this by always reloading ctx->used.

Reported-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Stephan Mueller <smueller@chronox.de>

parent 421d82f5

crypto/algif_skcipher.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -448,14 +448,13 @@ static int skcipher_recvmsg(struct kiocb unused, struct socket sock,
		while (!sg->length)
		sg++;

		used = ctx->used;
		if (!used) {
		if (!ctx->used) {
		err = skcipher_wait_for_data(sk, flags);
		if (err)
		goto unlock;
		}

		used = min_t(unsigned long, used, seglen);
		used = min_t(unsigned long, ctx->used, seglen);

		used = af_alg_make_sg(&ctx->rsgl, from, used, 1);
		err = used;