linux/net/tls/tls_device_fallback.c

473 lines
13 KiB
C

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