Commit 0b243d00 authored by Vakul Garg's avatar Vakul Garg Committed by David S. Miller
Browse files

net/tls: Combined memory allocation for decryption request 



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: default avatarVakul Garg <vakul.garg@nxp.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 78cbac64

include/net/tls.h

+0 −4
Original line number Diff line number Diff line
@@ -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 {

net/tls/tls_sw.c

+142 −96
Original line number Diff line number Diff line
@@ -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,
@@ -816,44 +888,18 @@ 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);

			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);

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