* [PATCH net-next v3 1/1] net/tls: Combined memory allocation for decryption request
2018-08-10 15:16 [PATCH net-next v3 0/1] net/tls: Combined memory allocation for decryption request Vakul Garg
@ 2018-08-10 15:16 ` Vakul Garg
2018-08-13 15:42 ` David Miller
0 siblings, 1 reply; 3+ messages in thread
From: Vakul Garg @ 2018-08-10 15:16 UTC (permalink / raw)
To: netdev; +Cc: borisp, aviadye, davejwatson, davem, Vakul Garg
For preparing decryption request, several memory chunks are required
(aead_req, sgin, sgout, iv, aad). For submitting the decrypt request to
an accelerator, it is required that the buffers which are read by the
accelerator must be dma-able and not come from stack. The buffers for
aad and iv can be separately kmalloced each, but it is inefficient.
This patch does a combined allocation for preparing decryption request
and then segments into aead_req || sgin || sgout || iv || aad.
Signed-off-by: Vakul Garg <vakul.garg@nxp.com>
---
Changes since v2:
- Rebased to not require following Doron Roberts-Kedes's patch.
"net/tls: Calculate nsg for zerocopy path without skb_cow_data."
include/net/tls.h | 4 -
net/tls/tls_sw.c | 238 ++++++++++++++++++++++++++++++++----------------------
2 files changed, 142 insertions(+), 100 deletions(-)
diff --git a/include/net/tls.h b/include/net/tls.h
index d8b3b6578c01..d5c683e8bb22 100644
--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -124,10 +124,6 @@ struct tls_sw_context_rx {
struct sk_buff *recv_pkt;
u8 control;
bool decrypted;
-
- char rx_aad_ciphertext[TLS_AAD_SPACE_SIZE];
- char rx_aad_plaintext[TLS_AAD_SPACE_SIZE];
-
};
struct tls_record_info {
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 83d67df33f0c..52fbe727d7c1 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -48,19 +48,13 @@ static int tls_do_decryption(struct sock *sk,
struct scatterlist *sgout,
char *iv_recv,
size_t data_len,
- struct sk_buff *skb,
- gfp_t flags)
+ struct aead_request *aead_req)
{
struct tls_context *tls_ctx = tls_get_ctx(sk);
struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
- struct aead_request *aead_req;
-
int ret;
- aead_req = aead_request_alloc(ctx->aead_recv, flags);
- if (!aead_req)
- return -ENOMEM;
-
+ aead_request_set_tfm(aead_req, ctx->aead_recv);
aead_request_set_ad(aead_req, TLS_AAD_SPACE_SIZE);
aead_request_set_crypt(aead_req, sgin, sgout,
data_len + tls_ctx->rx.tag_size,
@@ -69,8 +63,6 @@ static int tls_do_decryption(struct sock *sk,
crypto_req_done, &ctx->async_wait);
ret = crypto_wait_req(crypto_aead_decrypt(aead_req), &ctx->async_wait);
-
- aead_request_free(aead_req);
return ret;
}
@@ -657,8 +649,132 @@ static struct sk_buff *tls_wait_data(struct sock *sk, int flags,
return skb;
}
+/* This function decrypts the input skb into either out_iov or in out_sg
+ * or in skb buffers itself. The input parameter 'zc' indicates if
+ * zero-copy mode needs to be tried or not. With zero-copy mode, either
+ * out_iov or out_sg must be non-NULL. In case both out_iov and out_sg are
+ * NULL, then the decryption happens inside skb buffers itself, i.e.
+ * zero-copy gets disabled and 'zc' is updated.
+ */
+
+static int decrypt_internal(struct sock *sk, struct sk_buff *skb,
+ struct iov_iter *out_iov,
+ struct scatterlist *out_sg,
+ int *chunk, bool *zc)
+{
+ struct tls_context *tls_ctx = tls_get_ctx(sk);
+ struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
+ struct strp_msg *rxm = strp_msg(skb);
+ int n_sgin, n_sgout, nsg, mem_size, aead_size, err, pages = 0;
+ struct aead_request *aead_req;
+ struct sk_buff *unused;
+ u8 *aad, *iv, *mem = NULL;
+ struct scatterlist *sgin = NULL;
+ struct scatterlist *sgout = NULL;
+ const int data_len = rxm->full_len - tls_ctx->rx.overhead_size;
+
+ if (*zc && (out_iov || out_sg)) {
+ if (out_iov)
+ n_sgout = iov_iter_npages(out_iov, INT_MAX) + 1;
+ else
+ n_sgout = sg_nents(out_sg);
+ } else {
+ n_sgout = 0;
+ *zc = false;
+ }
+
+ n_sgin = skb_cow_data(skb, 0, &unused);
+ if (n_sgin < 1)
+ return -EBADMSG;
+
+ /* Increment to accommodate AAD */
+ n_sgin = n_sgin + 1;
+
+ nsg = n_sgin + n_sgout;
+
+ aead_size = sizeof(*aead_req) + crypto_aead_reqsize(ctx->aead_recv);
+ mem_size = aead_size + (nsg * sizeof(struct scatterlist));
+ mem_size = mem_size + TLS_AAD_SPACE_SIZE;
+ mem_size = mem_size + crypto_aead_ivsize(ctx->aead_recv);
+
+ /* Allocate a single block of memory which contains
+ * aead_req || sgin[] || sgout[] || aad || iv.
+ * This order achieves correct alignment for aead_req, sgin, sgout.
+ */
+ mem = kmalloc(mem_size, sk->sk_allocation);
+ if (!mem)
+ return -ENOMEM;
+
+ /* Segment the allocated memory */
+ aead_req = (struct aead_request *)mem;
+ sgin = (struct scatterlist *)(mem + aead_size);
+ sgout = sgin + n_sgin;
+ aad = (u8 *)(sgout + n_sgout);
+ iv = aad + TLS_AAD_SPACE_SIZE;
+
+ /* Prepare IV */
+ err = skb_copy_bits(skb, rxm->offset + TLS_HEADER_SIZE,
+ iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE,
+ tls_ctx->rx.iv_size);
+ if (err < 0) {
+ kfree(mem);
+ return err;
+ }
+ memcpy(iv, tls_ctx->rx.iv, TLS_CIPHER_AES_GCM_128_SALT_SIZE);
+
+ /* Prepare AAD */
+ tls_make_aad(aad, rxm->full_len - tls_ctx->rx.overhead_size,
+ tls_ctx->rx.rec_seq, tls_ctx->rx.rec_seq_size,
+ ctx->control);
+
+ /* Prepare sgin */
+ sg_init_table(sgin, n_sgin);
+ sg_set_buf(&sgin[0], aad, TLS_AAD_SPACE_SIZE);
+ err = skb_to_sgvec(skb, &sgin[1],
+ rxm->offset + tls_ctx->rx.prepend_size,
+ rxm->full_len - tls_ctx->rx.prepend_size);
+ if (err < 0) {
+ kfree(mem);
+ return err;
+ }
+
+ if (n_sgout) {
+ if (out_iov) {
+ sg_init_table(sgout, n_sgout);
+ sg_set_buf(&sgout[0], aad, TLS_AAD_SPACE_SIZE);
+
+ *chunk = 0;
+ err = zerocopy_from_iter(sk, out_iov, data_len, &pages,
+ chunk, &sgout[1],
+ (n_sgout - 1), false);
+ if (err < 0)
+ goto fallback_to_reg_recv;
+ } else if (out_sg) {
+ memcpy(sgout, out_sg, n_sgout * sizeof(*sgout));
+ } else {
+ goto fallback_to_reg_recv;
+ }
+ } else {
+fallback_to_reg_recv:
+ sgout = sgin;
+ pages = 0;
+ *chunk = 0;
+ *zc = false;
+ }
+
+ /* Prepare and submit AEAD request */
+ err = tls_do_decryption(sk, sgin, sgout, iv, data_len, aead_req);
+
+ /* Release the pages in case iov was mapped to pages */
+ for (; pages > 0; pages--)
+ put_page(sg_page(&sgout[pages]));
+
+ kfree(mem);
+ return err;
+}
+
static int decrypt_skb_update(struct sock *sk, struct sk_buff *skb,
- struct scatterlist *sgout, bool *zc)
+ struct iov_iter *dest, int *chunk, bool *zc)
{
struct tls_context *tls_ctx = tls_get_ctx(sk);
struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
@@ -671,7 +787,7 @@ static int decrypt_skb_update(struct sock *sk, struct sk_buff *skb,
return err;
#endif
if (!ctx->decrypted) {
- err = decrypt_skb(sk, skb, sgout);
+ err = decrypt_internal(sk, skb, dest, NULL, chunk, zc);
if (err < 0)
return err;
} else {
@@ -690,54 +806,10 @@ static int decrypt_skb_update(struct sock *sk, struct sk_buff *skb,
int decrypt_skb(struct sock *sk, struct sk_buff *skb,
struct scatterlist *sgout)
{
- struct tls_context *tls_ctx = tls_get_ctx(sk);
- struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
- char iv[TLS_CIPHER_AES_GCM_128_SALT_SIZE + MAX_IV_SIZE];
- struct scatterlist sgin_arr[MAX_SKB_FRAGS + 2];
- struct scatterlist *sgin = &sgin_arr[0];
- struct strp_msg *rxm = strp_msg(skb);
- int ret, nsg = ARRAY_SIZE(sgin_arr);
- struct sk_buff *unused;
-
- ret = skb_copy_bits(skb, rxm->offset + TLS_HEADER_SIZE,
- iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE,
- tls_ctx->rx.iv_size);
- if (ret < 0)
- return ret;
-
- memcpy(iv, tls_ctx->rx.iv, TLS_CIPHER_AES_GCM_128_SALT_SIZE);
- if (!sgout) {
- nsg = skb_cow_data(skb, 0, &unused) + 1;
- sgin = kmalloc_array(nsg, sizeof(*sgin), sk->sk_allocation);
- sgout = sgin;
- }
-
- sg_init_table(sgin, nsg);
- sg_set_buf(&sgin[0], ctx->rx_aad_ciphertext, TLS_AAD_SPACE_SIZE);
-
- nsg = skb_to_sgvec(skb, &sgin[1],
- rxm->offset + tls_ctx->rx.prepend_size,
- rxm->full_len - tls_ctx->rx.prepend_size);
- if (nsg < 0) {
- ret = nsg;
- goto out;
- }
-
- tls_make_aad(ctx->rx_aad_ciphertext,
- rxm->full_len - tls_ctx->rx.overhead_size,
- tls_ctx->rx.rec_seq,
- tls_ctx->rx.rec_seq_size,
- ctx->control);
-
- ret = tls_do_decryption(sk, sgin, sgout, iv,
- rxm->full_len - tls_ctx->rx.overhead_size,
- skb, sk->sk_allocation);
-
-out:
- if (sgin != &sgin_arr[0])
- kfree(sgin);
+ bool zc = true;
+ int chunk;
- return ret;
+ return decrypt_internal(sk, skb, NULL, sgout, &chunk, &zc);
}
static bool tls_sw_advance_skb(struct sock *sk, struct sk_buff *skb,
@@ -816,43 +888,17 @@ int tls_sw_recvmsg(struct sock *sk,
}
if (!ctx->decrypted) {
- int page_count;
- int to_copy;
-
- page_count = iov_iter_npages(&msg->msg_iter,
- MAX_SKB_FRAGS);
- to_copy = rxm->full_len - tls_ctx->rx.overhead_size;
- if (!is_kvec && to_copy <= len && page_count < MAX_SKB_FRAGS &&
- likely(!(flags & MSG_PEEK))) {
- struct scatterlist sgin[MAX_SKB_FRAGS + 1];
- int pages = 0;
+ int to_copy = rxm->full_len - tls_ctx->rx.overhead_size;
+ if (!is_kvec && to_copy <= len &&
+ likely(!(flags & MSG_PEEK)))
zc = true;
- sg_init_table(sgin, MAX_SKB_FRAGS + 1);
- sg_set_buf(&sgin[0], ctx->rx_aad_plaintext,
- TLS_AAD_SPACE_SIZE);
-
- err = zerocopy_from_iter(sk, &msg->msg_iter,
- to_copy, &pages,
- &chunk, &sgin[1],
- MAX_SKB_FRAGS, false);
- if (err < 0)
- goto fallback_to_reg_recv;
-
- err = decrypt_skb_update(sk, skb, sgin, &zc);
- for (; pages > 0; pages--)
- put_page(sg_page(&sgin[pages]));
- if (err < 0) {
- tls_err_abort(sk, EBADMSG);
- goto recv_end;
- }
- } else {
-fallback_to_reg_recv:
- err = decrypt_skb_update(sk, skb, NULL, &zc);
- if (err < 0) {
- tls_err_abort(sk, EBADMSG);
- goto recv_end;
- }
+
+ err = decrypt_skb_update(sk, skb, &msg->msg_iter,
+ &chunk, &zc);
+ if (err < 0) {
+ tls_err_abort(sk, EBADMSG);
+ goto recv_end;
}
ctx->decrypted = true;
}
@@ -903,7 +949,7 @@ ssize_t tls_sw_splice_read(struct socket *sock, loff_t *ppos,
int err = 0;
long timeo;
int chunk;
- bool zc;
+ bool zc = false;
lock_sock(sk);
@@ -920,7 +966,7 @@ ssize_t tls_sw_splice_read(struct socket *sock, loff_t *ppos,
}
if (!ctx->decrypted) {
- err = decrypt_skb_update(sk, skb, NULL, &zc);
+ err = decrypt_skb_update(sk, skb, NULL, &chunk, &zc);
if (err < 0) {
tls_err_abort(sk, EBADMSG);
--
2.13.6
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