crypto: af_alg - add async support to algif_aead

Following the async change for algif_skcipher
this patch adds similar async read to algif_aead.

changes in v3:
- add call to aead_reset_ctx directly from aead_put_sgl instead of calling
  them separatelly one after the other
- remove wait from aead_sock_destruct function as it is not needed
  when sock_hold is used

changes in v2:
- change internal data structures from fixed size arrays, limited to
  RSGL_MAX_ENTRIES, to linked list model with no artificial limitation.
- use sock_kmalloc instead of kmalloc for memory allocation
- use sock_hold instead of separate atomic ctr to wait for outstanding
  request

Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 237 insertions, 31 deletions

diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index 147069c9afd0..80a0f1a78551 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -13,7 +13,7 @@
  * any later version.
  */
 
-#include <crypto/aead.h>
+#include <crypto/internal/aead.h>
 #include <crypto/scatterwalk.h>
 #include <crypto/if_alg.h>
 #include <linux/init.h>
@@ -29,15 +29,24 @@ struct aead_sg_list {
         struct scatterlist sg[ALG_MAX_PAGES];
 };
 
+struct aead_async_rsgl {
+        struct af_alg_sgl sgl;
+        struct list_head list;
+};
+
+struct aead_async_req {
+        struct scatterlist *tsgl;
+        struct aead_async_rsgl first_rsgl;
+        struct list_head list;
+        struct kiocb *iocb;
+        unsigned int tsgls;
+        char iv[];
+};
+
 struct aead_ctx {
         struct aead_sg_list tsgl;
-        /*
-         * RSGL_MAX_ENTRIES is an artificial limit where user space at maximum
-         * can cause the kernel to allocate RSGL_MAX_ENTRIES * ALG_MAX_PAGES
-         * pages
-         */
-#define RSGL_MAX_ENTRIES ALG_MAX_PAGES
-        struct af_alg_sgl rsgl[RSGL_MAX_ENTRIES];
+        struct aead_async_rsgl first_rsgl;
+        struct list_head list;
 
         void *iv;
 
@@ -75,6 +84,17 @@ static inline bool aead_sufficient_data(struct aead_ctx *ctx)
         return ctx->used >= ctx->aead_assoclen + as;
 }
 
+static void aead_reset_ctx(struct aead_ctx *ctx)
+{
+        struct aead_sg_list *sgl = &ctx->tsgl;
+
+        sg_init_table(sgl->sg, ALG_MAX_PAGES);
+        sgl->cur = 0;
+        ctx->used = 0;
+        ctx->more = 0;
+        ctx->merge = 0;
+}
+
 static void aead_put_sgl(struct sock *sk)
 {
         struct alg_sock *ask = alg_sk(sk);
@@ -90,11 +110,7 @@ static void aead_put_sgl(struct sock *sk)
                 put_page(sg_page(sg + i));
                 sg_assign_page(sg + i, NULL);
         }
-        sg_init_table(sg, ALG_MAX_PAGES);
-        sgl->cur = 0;
-        ctx->used = 0;
-        ctx->more = 0;
-        ctx->merge = 0;
+        aead_reset_ctx(ctx);
 }
 
 static void aead_wmem_wakeup(struct sock *sk)
@@ -349,23 +365,188 @@ unlock:
         return err ?: size;
 }
 
-static int aead_recvmsg(struct socket *sock, struct msghdr *msg, size_t ignored, int flags)
+#define GET_ASYM_REQ(req, tfm) (struct aead_async_req *) \
+                ((char *)req + sizeof(struct aead_request) + \
+                 crypto_aead_reqsize(tfm))
+
+ #define GET_REQ_SIZE(tfm) sizeof(struct aead_async_req) + \
+        crypto_aead_reqsize(tfm) + crypto_aead_ivsize(tfm) + \
+        sizeof(struct aead_request)
+
+static void aead_async_cb(struct crypto_async_request *_req, int err)
+{
+        struct sock *sk = _req->data;
+        struct alg_sock *ask = alg_sk(sk);
+        struct aead_ctx *ctx = ask->private;
+        struct crypto_aead *tfm = crypto_aead_reqtfm(&ctx->aead_req);
+        struct aead_request *req = aead_request_cast(_req);
+        struct aead_async_req *areq = GET_ASYM_REQ(req, tfm);
+        struct scatterlist *sg = areq->tsgl;
+        struct aead_async_rsgl *rsgl;
+        struct kiocb *iocb = areq->iocb;
+        unsigned int i, reqlen = GET_REQ_SIZE(tfm);
+
+        list_for_each_entry(rsgl, &areq->list, list) {
+                af_alg_free_sg(&rsgl->sgl);
+                if (rsgl != &areq->first_rsgl)
+                        sock_kfree_s(sk, rsgl, sizeof(*rsgl));
+        }
+
+        for (i = 0; i < areq->tsgls; i++)
+                put_page(sg_page(sg + i));
+
+        sock_kfree_s(sk, areq->tsgl, sizeof(*areq->tsgl) * areq->tsgls);
+        sock_kfree_s(sk, req, reqlen);
+        __sock_put(sk);
+        iocb->ki_complete(iocb, err, err);
+}
+
+static int aead_recvmsg_async(struct socket *sock, struct msghdr *msg,
+                              int flags)
+{
+        struct sock *sk = sock->sk;
+        struct alg_sock *ask = alg_sk(sk);
+        struct aead_ctx *ctx = ask->private;
+        struct crypto_aead *tfm = crypto_aead_reqtfm(&ctx->aead_req);
+        struct aead_async_req *areq;
+        struct aead_request *req = NULL;
+        struct aead_sg_list *sgl = &ctx->tsgl;
+        struct aead_async_rsgl *last_rsgl = NULL, *rsgl;
+        unsigned int as = crypto_aead_authsize(tfm);
+        unsigned int i, reqlen = GET_REQ_SIZE(tfm);
+        int err = -ENOMEM;
+        unsigned long used;
+        size_t outlen;
+        size_t usedpages = 0;
+
+        lock_sock(sk);
+        if (ctx->more) {
+                err = aead_wait_for_data(sk, flags);
+                if (err)
+                        goto unlock;
+        }
+
+        used = ctx->used;
+        outlen = used;
+
+        if (!aead_sufficient_data(ctx))
+                goto unlock;
+
+        req = sock_kmalloc(sk, reqlen, GFP_KERNEL);
+        if (unlikely(!req))
+                goto unlock;
+
+        areq = GET_ASYM_REQ(req, tfm);
+        memset(&areq->first_rsgl, '\0', sizeof(areq->first_rsgl));
+        INIT_LIST_HEAD(&areq->list);
+        areq->iocb = msg->msg_iocb;
+        memcpy(areq->iv, ctx->iv, crypto_aead_ivsize(tfm));
+        aead_request_set_tfm(req, tfm);
+        aead_request_set_ad(req, ctx->aead_assoclen);
+        aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+                                  aead_async_cb, sk);
+        used -= ctx->aead_assoclen + (ctx->enc ? as : 0);
+
+        /* take over all tx sgls from ctx */
+        areq->tsgl = sock_kmalloc(sk, sizeof(*areq->tsgl) * sgl->cur,
+                                  GFP_KERNEL);
+        if (unlikely(!areq->tsgl))
+                goto free;
+
+        sg_init_table(areq->tsgl, sgl->cur);
+        for (i = 0; i < sgl->cur; i++)
+                sg_set_page(&areq->tsgl[i], sg_page(&sgl->sg[i]),
+                            sgl->sg[i].length, sgl->sg[i].offset);
+
+        areq->tsgls = sgl->cur;
+
+        /* create rx sgls */
+        while (iov_iter_count(&msg->msg_iter)) {
+                size_t seglen = min_t(size_t, iov_iter_count(&msg->msg_iter),
+                                      (outlen - usedpages));
+
+                if (list_empty(&areq->list)) {
+                        rsgl = &areq->first_rsgl;
+
+                } else {
+                        rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
+                        if (unlikely(!rsgl)) {
+                                err = -ENOMEM;
+                                goto free;
+                        }
+                }
+                rsgl->sgl.npages = 0;
+                list_add_tail(&rsgl->list, &areq->list);
+
+                /* make one iovec available as scatterlist */
+                err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
+                if (err < 0)
+                        goto free;
+
+                usedpages += err;
+
+                /* chain the new scatterlist with previous one */
+                if (last_rsgl)
+                        af_alg_link_sg(&last_rsgl->sgl, &rsgl->sgl);
+
+                last_rsgl = rsgl;
+
+                /* we do not need more iovecs as we have sufficient memory */
+                if (outlen <= usedpages)
+                        break;
+
+                iov_iter_advance(&msg->msg_iter, err);
+        }
+        err = -EINVAL;
+        /* ensure output buffer is sufficiently large */
+        if (usedpages < outlen)
+                goto free;
+
+        aead_request_set_crypt(req, areq->tsgl, areq->first_rsgl.sgl.sg, used,
+                               areq->iv);
+        err = ctx->enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req);
+        if (err) {
+                if (err == -EINPROGRESS) {
+                        sock_hold(sk);
+                        err = -EIOCBQUEUED;
+                        aead_reset_ctx(ctx);
+                        goto unlock;
+                } else if (err == -EBADMSG) {
+                        aead_put_sgl(sk);
+                }
+                goto free;
+        }
+        aead_put_sgl(sk);
+
+free:
+        list_for_each_entry(rsgl, &areq->list, list) {
+                af_alg_free_sg(&rsgl->sgl);
+                if (rsgl != &areq->first_rsgl)
+                        sock_kfree_s(sk, rsgl, sizeof(*rsgl));
+        }
+        if (areq->tsgl)
+                sock_kfree_s(sk, areq->tsgl, sizeof(*areq->tsgl) * areq->tsgls);
+        if (req)
+                sock_kfree_s(sk, req, reqlen);
+unlock:
+        aead_wmem_wakeup(sk);
+        release_sock(sk);
+        return err ? err : outlen;
+}
+
+static int aead_recvmsg_sync(struct socket *sock, struct msghdr *msg, int flags)
 {
         struct sock *sk = sock->sk;
         struct alg_sock *ask = alg_sk(sk);
         struct aead_ctx *ctx = ask->private;
         unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
         struct aead_sg_list *sgl = &ctx->tsgl;
-        unsigned int i = 0;
+        struct aead_async_rsgl *last_rsgl = NULL;
+        struct aead_async_rsgl *rsgl, *tmp;
         int err = -EINVAL;
         unsigned long used = 0;
         size_t outlen = 0;
         size_t usedpages = 0;
-        unsigned int cnt = 0;
-
-        /* Limit number of IOV blocks to be accessed below */
-        if (msg->msg_iter.nr_segs > RSGL_MAX_ENTRIES)
-                return -ENOMSG;
 
         lock_sock(sk);
 
@@ -417,21 +598,33 @@ static int aead_recvmsg(struct socket *sock, struct msghdr *msg, size_t ignored,
                 size_t seglen = min_t(size_t, iov_iter_count(&msg->msg_iter),
                                       (outlen - usedpages));
 
+                if (list_empty(&ctx->list)) {
+                        rsgl = &ctx->first_rsgl;
+                } else {
+                        rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
+                        if (unlikely(!rsgl)) {
+                                err = -ENOMEM;
+                                goto unlock;
+                        }
+                }
+                rsgl->sgl.npages = 0;
+                list_add_tail(&rsgl->list, &ctx->list);
+
                 /* make one iovec available as scatterlist */
-                err = af_alg_make_sg(&ctx->rsgl[cnt], &msg->msg_iter,
-                                     seglen);
+                err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
                 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]);
+                if (last_rsgl)
+                        af_alg_link_sg(&last_rsgl->sgl, &rsgl->sgl);
+
+                last_rsgl = rsgl;
 
                 /* we do not need more iovecs as we have sufficient memory */
                 if (outlen <= usedpages)
                         break;
                 iov_iter_advance(&msg->msg_iter, err);
-                cnt++;
         }
 
         err = -EINVAL;
@@ -440,8 +633,7 @@ static int aead_recvmsg(struct socket *sock, struct msghdr *msg, size_t ignored,
                 goto unlock;
 
         sg_mark_end(sgl->sg + sgl->cur - 1);
-
-        aead_request_set_crypt(&ctx->aead_req, sgl->sg, ctx->rsgl[0].sg,
+        aead_request_set_crypt(&ctx->aead_req, sgl->sg, ctx->first_rsgl.sgl.sg,
                                used, ctx->iv);
         aead_request_set_ad(&ctx->aead_req, ctx->aead_assoclen);
 
@@ -454,23 +646,35 @@ static int aead_recvmsg(struct socket *sock, struct msghdr *msg, size_t ignored,
                 /* EBADMSG implies a valid cipher operation took place */
                 if (err == -EBADMSG)
                         aead_put_sgl(sk);
+
                 goto unlock;
         }
 
         aead_put_sgl(sk);
-
         err = 0;
 
 unlock:
-        for (i = 0; i < cnt; i++)
-                af_alg_free_sg(&ctx->rsgl[i]);
-
+        list_for_each_entry_safe(rsgl, tmp, &ctx->list, list) {
+                af_alg_free_sg(&rsgl->sgl);
+                if (rsgl != &ctx->first_rsgl)
+                        sock_kfree_s(sk, rsgl, sizeof(*rsgl));
+                list_del(&rsgl->list);
+        }
+        INIT_LIST_HEAD(&ctx->list);
         aead_wmem_wakeup(sk);
         release_sock(sk);
 
         return err ? err : outlen;
 }
 
+static int aead_recvmsg(struct socket *sock, struct msghdr *msg, size_t ignored,
+                        int flags)
+{
+        return (msg->msg_iocb && !is_sync_kiocb(msg->msg_iocb)) ?
+                aead_recvmsg_async(sock, msg, flags) :
+                aead_recvmsg_sync(sock, msg, flags);
+}
+
 static unsigned int aead_poll(struct file *file, struct socket *sock,
                               poll_table *wait)
 {
@@ -540,6 +744,7 @@ static void aead_sock_destruct(struct sock *sk)
         unsigned int ivlen = crypto_aead_ivsize(
                                 crypto_aead_reqtfm(&ctx->aead_req));
 
+        WARN_ON(atomic_read(&sk->sk_refcnt) != 0);
         aead_put_sgl(sk);
         sock_kzfree_s(sk, ctx->iv, ivlen);
         sock_kfree_s(sk, ctx, ctx->len);
@@ -574,6 +779,7 @@ static int aead_accept_parent(void *private, struct sock *sk)
         ctx->aead_assoclen = 0;
         af_alg_init_completion(&ctx->completion);
         sg_init_table(ctx->tsgl.sg, ALG_MAX_PAGES);
+        INIT_LIST_HEAD(&ctx->list);
 
         ask->private = ctx;