1 files changed, 450 insertions, 0 deletions

diff --git a/net/tls/tls_device_fallback.c b/net/tls/tls_device_fallback.c
new file mode 100644
index 000000000000..748914abdb60
--- /dev/null
+++ b/net/tls/tls_device_fallback.c
@@ -0,0 +1,450 @@
+/* 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), 0, 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]);
+
+        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)
+{
+        skb_copy_header(nskb, skb);
+
+        skb_put(nskb, skb->len);
+        memcpy(nskb->data, skb->data, headln);
+        update_chksum(nskb, headln);
+
+        nskb->destructor = skb->destructor;
+        nskb->sk = skb->sk;
+        skb->destructor = NULL;
+        skb->sk = NULL;
+        refcount_add(nskb->truesize - skb->truesize,
+                     &nskb->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 *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);
+                WARN(1, "Record not found for seq %u\n", tcp_seq);
+                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 *ctx = tls_offload_ctx(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 *ctx = tls_offload_ctx(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:
+        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);
+}
+
+int tls_sw_fallback_init(struct sock *sk,
+                         struct tls_offload_context *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;
+}