469 lines
13 KiB
C
469 lines
13 KiB
C
/* Copyright (c) 2018, Mellanox Technologies All rights reserved.
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*
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* This software is available to you under a choice of one of two
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* licenses. You may choose to be licensed under the terms of the GNU
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* General Public License (GPL) Version 2, available from the file
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* COPYING in the main directory of this source tree, or the
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* OpenIB.org BSD license below:
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*
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* Redistribution and use in source and binary forms, with or
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* without modification, are permitted provided that the following
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* conditions are met:
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*
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* - Redistributions of source code must retain the above
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* copyright notice, this list of conditions and the following
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* disclaimer.
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*
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* - Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#include <net/tls.h>
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#include <crypto/aead.h>
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#include <crypto/scatterwalk.h>
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#include <net/ip6_checksum.h>
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static void chain_to_walk(struct scatterlist *sg, struct scatter_walk *walk)
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{
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struct scatterlist *src = walk->sg;
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int diff = walk->offset - src->offset;
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sg_set_page(sg, sg_page(src),
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src->length - diff, walk->offset);
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scatterwalk_crypto_chain(sg, sg_next(src), 2);
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}
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static int tls_enc_record(struct aead_request *aead_req,
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struct crypto_aead *aead, char *aad,
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char *iv, __be64 rcd_sn,
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struct scatter_walk *in,
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struct scatter_walk *out, int *in_len)
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{
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unsigned char buf[TLS_HEADER_SIZE + TLS_CIPHER_AES_GCM_128_IV_SIZE];
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struct scatterlist sg_in[3];
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struct scatterlist sg_out[3];
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u16 len;
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int rc;
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len = min_t(int, *in_len, ARRAY_SIZE(buf));
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scatterwalk_copychunks(buf, in, len, 0);
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scatterwalk_copychunks(buf, out, len, 1);
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*in_len -= len;
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if (!*in_len)
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return 0;
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scatterwalk_pagedone(in, 0, 1);
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scatterwalk_pagedone(out, 1, 1);
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len = buf[4] | (buf[3] << 8);
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len -= TLS_CIPHER_AES_GCM_128_IV_SIZE;
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tls_make_aad(aad, len - TLS_CIPHER_AES_GCM_128_TAG_SIZE,
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(char *)&rcd_sn, sizeof(rcd_sn), buf[0],
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TLS_1_2_VERSION);
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memcpy(iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE, buf + TLS_HEADER_SIZE,
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TLS_CIPHER_AES_GCM_128_IV_SIZE);
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sg_init_table(sg_in, ARRAY_SIZE(sg_in));
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sg_init_table(sg_out, ARRAY_SIZE(sg_out));
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sg_set_buf(sg_in, aad, TLS_AAD_SPACE_SIZE);
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sg_set_buf(sg_out, aad, TLS_AAD_SPACE_SIZE);
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chain_to_walk(sg_in + 1, in);
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chain_to_walk(sg_out + 1, out);
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*in_len -= len;
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if (*in_len < 0) {
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*in_len += TLS_CIPHER_AES_GCM_128_TAG_SIZE;
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/* the input buffer doesn't contain the entire record.
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* trim len accordingly. The resulting authentication tag
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* will contain garbage, but we don't care, so we won't
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* include any of it in the output skb
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* Note that we assume the output buffer length
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* is larger then input buffer length + tag size
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*/
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if (*in_len < 0)
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len += *in_len;
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*in_len = 0;
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}
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if (*in_len) {
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scatterwalk_copychunks(NULL, in, len, 2);
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scatterwalk_pagedone(in, 0, 1);
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scatterwalk_copychunks(NULL, out, len, 2);
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scatterwalk_pagedone(out, 1, 1);
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}
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len -= TLS_CIPHER_AES_GCM_128_TAG_SIZE;
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aead_request_set_crypt(aead_req, sg_in, sg_out, len, iv);
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rc = crypto_aead_encrypt(aead_req);
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return rc;
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}
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static void tls_init_aead_request(struct aead_request *aead_req,
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struct crypto_aead *aead)
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{
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aead_request_set_tfm(aead_req, aead);
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aead_request_set_ad(aead_req, TLS_AAD_SPACE_SIZE);
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}
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static struct aead_request *tls_alloc_aead_request(struct crypto_aead *aead,
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gfp_t flags)
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{
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unsigned int req_size = sizeof(struct aead_request) +
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crypto_aead_reqsize(aead);
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struct aead_request *aead_req;
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aead_req = kzalloc(req_size, flags);
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if (aead_req)
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tls_init_aead_request(aead_req, aead);
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return aead_req;
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}
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static int tls_enc_records(struct aead_request *aead_req,
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struct crypto_aead *aead, struct scatterlist *sg_in,
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struct scatterlist *sg_out, char *aad, char *iv,
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u64 rcd_sn, int len)
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{
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struct scatter_walk out, in;
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int rc;
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scatterwalk_start(&in, sg_in);
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scatterwalk_start(&out, sg_out);
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do {
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rc = tls_enc_record(aead_req, aead, aad, iv,
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cpu_to_be64(rcd_sn), &in, &out, &len);
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rcd_sn++;
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} while (rc == 0 && len);
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scatterwalk_done(&in, 0, 0);
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scatterwalk_done(&out, 1, 0);
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return rc;
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}
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/* Can't use icsk->icsk_af_ops->send_check here because the ip addresses
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* might have been changed by NAT.
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*/
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static void update_chksum(struct sk_buff *skb, int headln)
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{
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struct tcphdr *th = tcp_hdr(skb);
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int datalen = skb->len - headln;
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const struct ipv6hdr *ipv6h;
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const struct iphdr *iph;
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/* We only changed the payload so if we are using partial we don't
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* need to update anything.
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*/
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if (likely(skb->ip_summed == CHECKSUM_PARTIAL))
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return;
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skb->ip_summed = CHECKSUM_PARTIAL;
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skb->csum_start = skb_transport_header(skb) - skb->head;
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skb->csum_offset = offsetof(struct tcphdr, check);
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if (skb->sk->sk_family == AF_INET6) {
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ipv6h = ipv6_hdr(skb);
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th->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
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datalen, IPPROTO_TCP, 0);
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} else {
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iph = ip_hdr(skb);
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th->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, datalen,
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IPPROTO_TCP, 0);
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}
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}
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static void complete_skb(struct sk_buff *nskb, struct sk_buff *skb, int headln)
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{
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struct sock *sk = skb->sk;
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int delta;
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skb_copy_header(nskb, skb);
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skb_put(nskb, skb->len);
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memcpy(nskb->data, skb->data, headln);
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nskb->destructor = skb->destructor;
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nskb->sk = sk;
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skb->destructor = NULL;
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skb->sk = NULL;
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update_chksum(nskb, headln);
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delta = nskb->truesize - skb->truesize;
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if (likely(delta < 0))
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WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));
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else if (delta)
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refcount_add(delta, &sk->sk_wmem_alloc);
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}
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/* This function may be called after the user socket is already
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* closed so make sure we don't use anything freed during
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* tls_sk_proto_close here
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*/
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static int fill_sg_in(struct scatterlist *sg_in,
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struct sk_buff *skb,
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struct tls_offload_context_tx *ctx,
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u64 *rcd_sn,
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s32 *sync_size,
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int *resync_sgs)
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{
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int tcp_payload_offset = skb_transport_offset(skb) + tcp_hdrlen(skb);
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int payload_len = skb->len - tcp_payload_offset;
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u32 tcp_seq = ntohl(tcp_hdr(skb)->seq);
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struct tls_record_info *record;
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unsigned long flags;
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int remaining;
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int i;
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spin_lock_irqsave(&ctx->lock, flags);
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record = tls_get_record(ctx, tcp_seq, rcd_sn);
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if (!record) {
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spin_unlock_irqrestore(&ctx->lock, flags);
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return -EINVAL;
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}
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*sync_size = tcp_seq - tls_record_start_seq(record);
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if (*sync_size < 0) {
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int is_start_marker = tls_record_is_start_marker(record);
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spin_unlock_irqrestore(&ctx->lock, flags);
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/* This should only occur if the relevant record was
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* already acked. In that case it should be ok
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* to drop the packet and avoid retransmission.
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*
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* There is a corner case where the packet contains
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* both an acked and a non-acked record.
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* We currently don't handle that case and rely
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* on TCP to retranmit a packet that doesn't contain
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* already acked payload.
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*/
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if (!is_start_marker)
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*sync_size = 0;
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return -EINVAL;
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}
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remaining = *sync_size;
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for (i = 0; remaining > 0; i++) {
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skb_frag_t *frag = &record->frags[i];
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__skb_frag_ref(frag);
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sg_set_page(sg_in + i, skb_frag_page(frag),
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skb_frag_size(frag), frag->page_offset);
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remaining -= skb_frag_size(frag);
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if (remaining < 0)
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sg_in[i].length += remaining;
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}
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*resync_sgs = i;
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spin_unlock_irqrestore(&ctx->lock, flags);
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if (skb_to_sgvec(skb, &sg_in[i], tcp_payload_offset, payload_len) < 0)
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return -EINVAL;
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return 0;
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}
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static void fill_sg_out(struct scatterlist sg_out[3], void *buf,
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struct tls_context *tls_ctx,
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struct sk_buff *nskb,
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int tcp_payload_offset,
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int payload_len,
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int sync_size,
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void *dummy_buf)
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{
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sg_set_buf(&sg_out[0], dummy_buf, sync_size);
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sg_set_buf(&sg_out[1], nskb->data + tcp_payload_offset, payload_len);
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/* Add room for authentication tag produced by crypto */
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dummy_buf += sync_size;
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sg_set_buf(&sg_out[2], dummy_buf, TLS_CIPHER_AES_GCM_128_TAG_SIZE);
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}
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static struct sk_buff *tls_enc_skb(struct tls_context *tls_ctx,
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struct scatterlist sg_out[3],
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struct scatterlist *sg_in,
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struct sk_buff *skb,
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s32 sync_size, u64 rcd_sn)
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{
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int tcp_payload_offset = skb_transport_offset(skb) + tcp_hdrlen(skb);
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struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx);
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int payload_len = skb->len - tcp_payload_offset;
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void *buf, *iv, *aad, *dummy_buf;
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struct aead_request *aead_req;
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struct sk_buff *nskb = NULL;
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int buf_len;
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aead_req = tls_alloc_aead_request(ctx->aead_send, GFP_ATOMIC);
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if (!aead_req)
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return NULL;
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buf_len = TLS_CIPHER_AES_GCM_128_SALT_SIZE +
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TLS_CIPHER_AES_GCM_128_IV_SIZE +
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TLS_AAD_SPACE_SIZE +
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sync_size +
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TLS_CIPHER_AES_GCM_128_TAG_SIZE;
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buf = kmalloc(buf_len, GFP_ATOMIC);
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if (!buf)
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goto free_req;
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iv = buf;
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memcpy(iv, tls_ctx->crypto_send.aes_gcm_128.salt,
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TLS_CIPHER_AES_GCM_128_SALT_SIZE);
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aad = buf + TLS_CIPHER_AES_GCM_128_SALT_SIZE +
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TLS_CIPHER_AES_GCM_128_IV_SIZE;
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dummy_buf = aad + TLS_AAD_SPACE_SIZE;
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nskb = alloc_skb(skb_headroom(skb) + skb->len, GFP_ATOMIC);
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if (!nskb)
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goto free_buf;
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skb_reserve(nskb, skb_headroom(skb));
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fill_sg_out(sg_out, buf, tls_ctx, nskb, tcp_payload_offset,
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payload_len, sync_size, dummy_buf);
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if (tls_enc_records(aead_req, ctx->aead_send, sg_in, sg_out, aad, iv,
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rcd_sn, sync_size + payload_len) < 0)
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goto free_nskb;
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complete_skb(nskb, skb, tcp_payload_offset);
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/* validate_xmit_skb_list assumes that if the skb wasn't segmented
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* nskb->prev will point to the skb itself
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*/
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nskb->prev = nskb;
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free_buf:
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kfree(buf);
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free_req:
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kfree(aead_req);
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return nskb;
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free_nskb:
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kfree_skb(nskb);
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nskb = NULL;
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goto free_buf;
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}
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static struct sk_buff *tls_sw_fallback(struct sock *sk, struct sk_buff *skb)
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{
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int tcp_payload_offset = skb_transport_offset(skb) + tcp_hdrlen(skb);
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struct tls_context *tls_ctx = tls_get_ctx(sk);
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struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx);
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int payload_len = skb->len - tcp_payload_offset;
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struct scatterlist *sg_in, sg_out[3];
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struct sk_buff *nskb = NULL;
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int sg_in_max_elements;
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int resync_sgs = 0;
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s32 sync_size = 0;
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u64 rcd_sn;
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/* worst case is:
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* MAX_SKB_FRAGS in tls_record_info
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* MAX_SKB_FRAGS + 1 in SKB head and frags.
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*/
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sg_in_max_elements = 2 * MAX_SKB_FRAGS + 1;
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if (!payload_len)
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return skb;
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sg_in = kmalloc_array(sg_in_max_elements, sizeof(*sg_in), GFP_ATOMIC);
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if (!sg_in)
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goto free_orig;
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sg_init_table(sg_in, sg_in_max_elements);
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sg_init_table(sg_out, ARRAY_SIZE(sg_out));
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if (fill_sg_in(sg_in, skb, ctx, &rcd_sn, &sync_size, &resync_sgs)) {
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/* bypass packets before kernel TLS socket option was set */
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if (sync_size < 0 && payload_len <= -sync_size)
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nskb = skb_get(skb);
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goto put_sg;
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}
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nskb = tls_enc_skb(tls_ctx, sg_out, sg_in, skb, sync_size, rcd_sn);
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put_sg:
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while (resync_sgs)
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put_page(sg_page(&sg_in[--resync_sgs]));
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kfree(sg_in);
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free_orig:
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if (nskb)
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consume_skb(skb);
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else
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kfree_skb(skb);
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return nskb;
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}
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struct sk_buff *tls_validate_xmit_skb(struct sock *sk,
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struct net_device *dev,
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struct sk_buff *skb)
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{
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if (dev == tls_get_ctx(sk)->netdev)
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return skb;
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return tls_sw_fallback(sk, skb);
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}
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EXPORT_SYMBOL_GPL(tls_validate_xmit_skb);
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struct sk_buff *tls_encrypt_skb(struct sk_buff *skb)
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{
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return tls_sw_fallback(skb->sk, skb);
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}
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EXPORT_SYMBOL_GPL(tls_encrypt_skb);
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int tls_sw_fallback_init(struct sock *sk,
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struct tls_offload_context_tx *offload_ctx,
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struct tls_crypto_info *crypto_info)
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{
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const u8 *key;
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int rc;
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offload_ctx->aead_send =
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crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC);
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if (IS_ERR(offload_ctx->aead_send)) {
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rc = PTR_ERR(offload_ctx->aead_send);
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pr_err_ratelimited("crypto_alloc_aead failed rc=%d\n", rc);
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offload_ctx->aead_send = NULL;
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goto err_out;
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}
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key = ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->key;
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rc = crypto_aead_setkey(offload_ctx->aead_send, key,
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TLS_CIPHER_AES_GCM_128_KEY_SIZE);
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if (rc)
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goto free_aead;
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rc = crypto_aead_setauthsize(offload_ctx->aead_send,
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TLS_CIPHER_AES_GCM_128_TAG_SIZE);
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if (rc)
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goto free_aead;
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return 0;
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free_aead:
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crypto_free_aead(offload_ctx->aead_send);
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err_out:
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return rc;
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}
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