diff options
| -rw-r--r-- | Documentation/networking/tls-offload.rst | 19 | ||||
| -rw-r--r-- | include/net/tls.h | 34 | ||||
| -rw-r--r-- | net/tls/tls_device.c | 105 | ||||
| -rw-r--r-- | net/tls/tls_sw.c | 2 |
4 files changed, 145 insertions, 15 deletions
diff --git a/Documentation/networking/tls-offload.rst b/Documentation/networking/tls-offload.rst index eb7c9b81ccf5..d134d63307e7 100644 --- a/Documentation/networking/tls-offload.rst +++ b/Documentation/networking/tls-offload.rst @@ -268,6 +268,9 @@ Device can only detect that segment 4 also contains a TLS header if it knows the length of the previous record from segment 2. In this case the device will lose synchronization with the stream. +Stream scan resynchronization +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + When the device gets out of sync and the stream reaches TCP sequence numbers more than a max size record past the expected TCP sequence number, the device starts scanning for a known header pattern. For example @@ -298,6 +301,22 @@ Special care has to be taken if the confirmation request is passed asynchronously to the packet stream and record may get processed by the kernel before the confirmation request. +Stack-driven resynchronization +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The driver may also request the stack to perform resynchronization +whenever it sees the records are no longer getting decrypted. +If the connection is configured in this mode the stack automatically +schedules resynchronization after it has received two completely encrypted +records. + +The stack waits for the socket to drain and informs the device about +the next expected record number and its TCP sequence number. If the +records continue to be received fully encrypted stack retries the +synchronization with an exponential back off (first after 2 encrypted +records, then after 4 records, after 8, after 16... up until every +128 records). + Error handling ============== diff --git a/include/net/tls.h b/include/net/tls.h index 1c512da5e4f4..28eca6a3b615 100644 --- a/include/net/tls.h +++ b/include/net/tls.h @@ -303,10 +303,33 @@ struct tlsdev_ops { struct sock *sk, u32 seq, u8 *rcd_sn); }; +enum tls_offload_sync_type { + TLS_OFFLOAD_SYNC_TYPE_DRIVER_REQ = 0, + TLS_OFFLOAD_SYNC_TYPE_CORE_NEXT_HINT = 1, +}; + +#define TLS_DEVICE_RESYNC_NH_START_IVAL 2 +#define TLS_DEVICE_RESYNC_NH_MAX_IVAL 128 + struct tls_offload_context_rx { /* sw must be the first member of tls_offload_context_rx */ struct tls_sw_context_rx sw; - atomic64_t resync_req; + enum tls_offload_sync_type resync_type; + /* this member is set regardless of resync_type, to avoid branches */ + u8 resync_nh_reset:1; + /* CORE_NEXT_HINT-only member, but use the hole here */ + u8 resync_nh_do_now:1; + union { + /* TLS_OFFLOAD_SYNC_TYPE_DRIVER_REQ */ + struct { + atomic64_t resync_req; + }; + /* TLS_OFFLOAD_SYNC_TYPE_CORE_NEXT_HINT */ + struct { + u32 decrypted_failed; + u32 decrypted_tgt; + } resync_nh; + }; u8 driver_state[] __aligned(8); /* The TLS layer reserves room for driver specific state * Currently the belief is that there is not enough @@ -587,6 +610,13 @@ static inline void tls_offload_rx_resync_request(struct sock *sk, __be32 seq) atomic64_set(&rx_ctx->resync_req, ((u64)ntohl(seq) << 32) | 1); } +static inline void +tls_offload_rx_resync_set_type(struct sock *sk, enum tls_offload_sync_type type) +{ + struct tls_context *tls_ctx = tls_get_ctx(sk); + + tls_offload_ctx_rx(tls_ctx)->resync_type = type; +} int tls_proccess_cmsg(struct sock *sk, struct msghdr *msg, unsigned char *record_type); @@ -608,6 +638,6 @@ int tls_sw_fallback_init(struct sock *sk, int tls_set_device_offload_rx(struct sock *sk, struct tls_context *ctx); void tls_device_offload_cleanup_rx(struct sock *sk); -void tls_device_rx_resync_new_rec(struct sock *sk, u32 seq); +void tls_device_rx_resync_new_rec(struct sock *sk, u32 rcd_len, u32 seq); #endif /* _TLS_OFFLOAD_H */ diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c index 0ecfa0ee415d..477c869c69c8 100644 --- a/net/tls/tls_device.c +++ b/net/tls/tls_device.c @@ -563,10 +563,12 @@ static void tls_device_resync_rx(struct tls_context *tls_ctx, clear_bit_unlock(TLS_RX_SYNC_RUNNING, &tls_ctx->flags); } -void tls_device_rx_resync_new_rec(struct sock *sk, u32 seq) +void tls_device_rx_resync_new_rec(struct sock *sk, u32 rcd_len, u32 seq) { struct tls_context *tls_ctx = tls_get_ctx(sk); struct tls_offload_context_rx *rx_ctx; + u8 rcd_sn[TLS_MAX_REC_SEQ_SIZE]; + struct tls_prot_info *prot; u32 is_req_pending; s64 resync_req; u32 req_seq; @@ -574,15 +576,84 @@ void tls_device_rx_resync_new_rec(struct sock *sk, u32 seq) if (tls_ctx->rx_conf != TLS_HW) return; + prot = &tls_ctx->prot_info; rx_ctx = tls_offload_ctx_rx(tls_ctx); - resync_req = atomic64_read(&rx_ctx->resync_req); - req_seq = resync_req >> 32; - seq += TLS_HEADER_SIZE - 1; - is_req_pending = resync_req; - - if (unlikely(is_req_pending) && req_seq == seq && - atomic64_try_cmpxchg(&rx_ctx->resync_req, &resync_req, 0)) - tls_device_resync_rx(tls_ctx, sk, seq, tls_ctx->rx.rec_seq); + memcpy(rcd_sn, tls_ctx->rx.rec_seq, prot->rec_seq_size); + + switch (rx_ctx->resync_type) { + case TLS_OFFLOAD_SYNC_TYPE_DRIVER_REQ: + resync_req = atomic64_read(&rx_ctx->resync_req); + req_seq = resync_req >> 32; + seq += TLS_HEADER_SIZE - 1; + is_req_pending = resync_req; + + if (likely(!is_req_pending) || req_seq != seq || + !atomic64_try_cmpxchg(&rx_ctx->resync_req, &resync_req, 0)) + return; + break; + case TLS_OFFLOAD_SYNC_TYPE_CORE_NEXT_HINT: + if (likely(!rx_ctx->resync_nh_do_now)) + return; + + /* head of next rec is already in, note that the sock_inq will + * include the currently parsed message when called from parser + */ + if (tcp_inq(sk) > rcd_len) + return; + + rx_ctx->resync_nh_do_now = 0; + seq += rcd_len; + tls_bigint_increment(rcd_sn, prot->rec_seq_size); + break; + } + + tls_device_resync_rx(tls_ctx, sk, seq, rcd_sn); +} + +static void tls_device_core_ctrl_rx_resync(struct tls_context *tls_ctx, + struct tls_offload_context_rx *ctx, + struct sock *sk, struct sk_buff *skb) +{ + struct strp_msg *rxm; + + /* device will request resyncs by itself based on stream scan */ + if (ctx->resync_type != TLS_OFFLOAD_SYNC_TYPE_CORE_NEXT_HINT) + return; + /* already scheduled */ + if (ctx->resync_nh_do_now) + return; + /* seen decrypted fragments since last fully-failed record */ + if (ctx->resync_nh_reset) { + ctx->resync_nh_reset = 0; + ctx->resync_nh.decrypted_failed = 1; + ctx->resync_nh.decrypted_tgt = TLS_DEVICE_RESYNC_NH_START_IVAL; + return; + } + + if (++ctx->resync_nh.decrypted_failed <= ctx->resync_nh.decrypted_tgt) + return; + + /* doing resync, bump the next target in case it fails */ + if (ctx->resync_nh.decrypted_tgt < TLS_DEVICE_RESYNC_NH_MAX_IVAL) + ctx->resync_nh.decrypted_tgt *= 2; + else + ctx->resync_nh.decrypted_tgt += TLS_DEVICE_RESYNC_NH_MAX_IVAL; + + rxm = strp_msg(skb); + + /* head of next rec is already in, parser will sync for us */ + if (tcp_inq(sk) > rxm->full_len) { + ctx->resync_nh_do_now = 1; + } else { + struct tls_prot_info *prot = &tls_ctx->prot_info; + u8 rcd_sn[TLS_MAX_REC_SEQ_SIZE]; + + memcpy(rcd_sn, tls_ctx->rx.rec_seq, prot->rec_seq_size); + tls_bigint_increment(rcd_sn, prot->rec_seq_size); + + tls_device_resync_rx(tls_ctx, sk, tcp_sk(sk)->copied_seq, + rcd_sn); + } } static int tls_device_reencrypt(struct sock *sk, struct sk_buff *skb) @@ -686,12 +757,21 @@ int tls_device_decrypted(struct sock *sk, struct sk_buff *skb) ctx->sw.decrypted |= is_decrypted; - /* Return immedeatly if the record is either entirely plaintext or + /* Return immediately if the record is either entirely plaintext or * entirely ciphertext. Otherwise handle reencrypt partially decrypted * record. */ - return (is_encrypted || is_decrypted) ? 0 : - tls_device_reencrypt(sk, skb); + if (is_decrypted) { + ctx->resync_nh_reset = 1; + return 0; + } + if (is_encrypted) { + tls_device_core_ctrl_rx_resync(tls_ctx, ctx, sk, skb); + return 0; + } + + ctx->resync_nh_reset = 1; + return tls_device_reencrypt(sk, skb); } static void tls_device_attach(struct tls_context *ctx, struct sock *sk, @@ -917,6 +997,7 @@ int tls_set_device_offload_rx(struct sock *sk, struct tls_context *ctx) rc = -ENOMEM; goto release_netdev; } + context->resync_nh_reset = 1; ctx->priv_ctx_rx = context; rc = tls_set_sw_offload(sk, ctx, 0); diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index bc3a1b188d4a..533eaa4826e5 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -2015,7 +2015,7 @@ static int tls_read_size(struct strparser *strp, struct sk_buff *skb) goto read_failure; } #ifdef CONFIG_TLS_DEVICE - tls_device_rx_resync_new_rec(strp->sk, + tls_device_rx_resync_new_rec(strp->sk, data_len + TLS_HEADER_SIZE, TCP_SKB_CB(skb)->seq + rxm->offset); #endif return data_len + TLS_HEADER_SIZE; |