Stephan,
On Sat, 14 May 2016, Tadeusz Struk wrote:
From: Stephan Mueller <smueller@xxxxxxxxxx>
This patch adds the user space interface for asymmetric ciphers. The
interface allows the use of sendmsg as well as vmsplice to provide data.
This version has been rebased on top of 4.6 and a few chackpatch issues
have been fixed.
Signed-off-by: Stephan Mueller <smueller@xxxxxxxxxx>
Signed-off-by: Tadeusz Struk <tadeusz.struk@xxxxxxxxx>
---
diff --git a/crypto/algif_akcipher.c b/crypto/algif_akcipher.c
new file mode 100644
index 0000000..6342b6e
--- /dev/null
+++ b/crypto/algif_akcipher.c
+
+static int akcipher_recvmsg(struct socket *sock, struct msghdr *msg,
+ size_t ignored, int flags)
+{
+ struct sock *sk = sock->sk;
+ struct alg_sock *ask = alg_sk(sk);
+ struct akcipher_ctx *ctx = ask->private;
+ struct akcipher_sg_list *sgl = &ctx->tsgl;
+ unsigned int i = 0;
+ int err;
+ unsigned long used = 0;
+ size_t usedpages = 0;
+ unsigned int cnt = 0;
+
+ /* Limit number of IOV blocks to be accessed below */
+ if (msg->msg_iter.nr_segs > ALG_MAX_PAGES)
+ return -ENOMSG;
+
+ lock_sock(sk);
+
+ if (ctx->more) {
+ err = akcipher_wait_for_data(sk, flags);
+ if (err)
+ goto unlock;
+ }
+
+ used = ctx->used;
+
+ /* convert iovecs of output buffers into scatterlists */
+ while (iov_iter_count(&msg->msg_iter)) {
+ /* make one iovec available as scatterlist */
+ err = af_alg_make_sg(&ctx->rsgl[cnt], &msg->msg_iter,
+ iov_iter_count(&msg->msg_iter));
+ if (err < 0)
+ goto unlock;
+ usedpages += err;
+ /* chain the new scatterlist with previous one */
+ if (cnt)
+ af_alg_link_sg(&ctx->rsgl[cnt - 1], &ctx->rsgl[cnt]);
+
+ iov_iter_advance(&msg->msg_iter, err);
+ cnt++;
+ }
+
+ /* ensure output buffer is sufficiently large */
+ if (usedpages < akcipher_calcsize(ctx)) {
+ err = -EMSGSIZE;
+ goto unlock;
+ }
Why is the size of the output buffer enforced here instead of depending on
the algorithm implementation?
Thanks,
Mat
+ sg_mark_end(sgl->sg + sgl->cur - 1);
+
+ akcipher_request_set_crypt(&ctx->req, sgl->sg, ctx->rsgl[0].sg, used,
+ usedpages);
+ switch (ctx->op) {
+ case ALG_OP_VERIFY:
+ err = crypto_akcipher_verify(&ctx->req);
+ break;
+ case ALG_OP_SIGN:
+ err = crypto_akcipher_sign(&ctx->req);
+ break;
+ case ALG_OP_ENCRYPT:
+ err = crypto_akcipher_encrypt(&ctx->req);
+ break;
+ case ALG_OP_DECRYPT:
+ err = crypto_akcipher_decrypt(&ctx->req);
+ break;
+ default:
+ err = -EFAULT;
+ goto unlock;
+ }
+
+ err = af_alg_wait_for_completion(err, &ctx->completion);
+
+ if (err) {
+ /* EBADMSG implies a valid cipher operation took place */
+ if (err == -EBADMSG)
+ akcipher_put_sgl(sk);
+ goto unlock;
+ }
+
+ akcipher_put_sgl(sk);
+
+unlock:
+ for (i = 0; i < cnt; i++)
+ af_alg_free_sg(&ctx->rsgl[i]);
+
+ akcipher_wmem_wakeup(sk);
+ release_sock(sk);
+
+ return err ? err : ctx->req.dst_len;
+}
--
Mat Martineau
Intel OTC
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