[PATCH v2 2/2] crypto: af_alg - add async support to algif_aead

From: Tadeusz Struk
Date: Mon Feb 01 2016 - 14:21:51 EST


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

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@xxxxxxxxx>
---
crypto/algif_aead.c | 280 +++++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 249 insertions(+), 31 deletions(-)

diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index 147069c..47d4f71 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 +110,6 @@ 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;
}

static void aead_wmem_wakeup(struct sock *sk)
@@ -240,6 +255,7 @@ static int aead_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
if (!aead_writable(sk)) {
/* user space sent too much data */
aead_put_sgl(sk);
+ aead_reset_ctx(ctx);
err = -EMSGSIZE;
goto unlock;
}
@@ -251,6 +267,7 @@ static int aead_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)

if (sgl->cur >= ALG_MAX_PAGES) {
aead_put_sgl(sk);
+ aead_reset_ctx(ctx);
err = -E2BIG;
goto unlock;
}
@@ -287,6 +304,7 @@ static int aead_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
ctx->more = msg->msg_flags & MSG_MORE;
if (!ctx->more && !aead_sufficient_data(ctx)) {
aead_put_sgl(sk);
+ aead_reset_ctx(ctx);
err = -EMSGSIZE;
}

@@ -322,6 +340,7 @@ static ssize_t aead_sendpage(struct socket *sock, struct page *page,
if (!aead_writable(sk)) {
/* user space sent too much data */
aead_put_sgl(sk);
+ aead_reset_ctx(ctx);
err = -EMSGSIZE;
goto unlock;
}
@@ -339,6 +358,7 @@ done:
ctx->more = flags & MSG_MORE;
if (!ctx->more && !aead_sufficient_data(ctx)) {
aead_put_sgl(sk);
+ aead_reset_ctx(ctx);
err = -EMSGSIZE;
}

@@ -349,23 +369,189 @@ 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);
+ aead_reset_ctx(ctx);
+ }
+ goto free;
+ }
+ aead_put_sgl(sk);
+ aead_reset_ctx(ctx);
+
+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 +603,33 @@ 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 +638,7 @@ 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);

@@ -452,25 +649,40 @@ static int aead_recvmsg(struct socket *sock, struct msghdr *msg, size_t ignored,

if (err) {
/* EBADMSG implies a valid cipher operation took place */
- if (err == -EBADMSG)
+ if (err == -EBADMSG) {
aead_put_sgl(sk);
+ aead_reset_ctx(ctx);
+ }
goto unlock;
}

aead_put_sgl(sk);
+ aead_reset_ctx(ctx);

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)
{
@@ -539,7 +751,12 @@ static void aead_sock_destruct(struct sock *sk)
struct aead_ctx *ctx = ask->private;
unsigned int ivlen = crypto_aead_ivsize(
crypto_aead_reqtfm(&ctx->aead_req));
+ int ctr = 0;
+
+ while (atomic_read(&sk->sk_refcnt) != 0 && ctr++ < 10)
+ msleep(100);

+ 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 +791,7 @@ 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;