From ca2f5f21dbbd5e3a00cd3e97f728aa2ca0b2e011 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Fri, 29 May 2020 16:06:41 -0700 Subject: bpf: Refactor sockmap redirect code so its easy to reuse We will need this block of code called from tls context shortly lets refactor the redirect logic so its easy to use. This also cleans up the switch stmt so we have fewer fallthrough cases. No logic changes are intended. Fixes: d829e9c4112b5 ("tls: convert to generic sk_msg interface") Signed-off-by: John Fastabend Signed-off-by: Alexei Starovoitov Reviewed-by: Jakub Sitnicki Acked-by: Song Liu Link: https://lore.kernel.org/bpf/159079360110.5745.7024009076049029819.stgit@john-Precision-5820-Tower Signed-off-by: Alexei Starovoitov --- net/core/skmsg.c | 55 ++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 34 insertions(+), 21 deletions(-) (limited to 'net/core/skmsg.c') diff --git a/net/core/skmsg.c b/net/core/skmsg.c index c479372f2cd2..9d72f71e9b47 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -682,13 +682,43 @@ static struct sk_psock *sk_psock_from_strp(struct strparser *strp) return container_of(parser, struct sk_psock, parser); } -static void sk_psock_verdict_apply(struct sk_psock *psock, - struct sk_buff *skb, int verdict) +static void sk_psock_skb_redirect(struct sk_psock *psock, struct sk_buff *skb) { struct sk_psock *psock_other; struct sock *sk_other; bool ingress; + sk_other = tcp_skb_bpf_redirect_fetch(skb); + if (unlikely(!sk_other)) { + kfree_skb(skb); + return; + } + psock_other = sk_psock(sk_other); + if (!psock_other || sock_flag(sk_other, SOCK_DEAD) || + !sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED)) { + kfree_skb(skb); + return; + } + + ingress = tcp_skb_bpf_ingress(skb); + if ((!ingress && sock_writeable(sk_other)) || + (ingress && + atomic_read(&sk_other->sk_rmem_alloc) <= + sk_other->sk_rcvbuf)) { + if (!ingress) + skb_set_owner_w(skb, sk_other); + skb_queue_tail(&psock_other->ingress_skb, skb); + schedule_work(&psock_other->work); + } else { + kfree_skb(skb); + } +} + +static void sk_psock_verdict_apply(struct sk_psock *psock, + struct sk_buff *skb, int verdict) +{ + struct sock *sk_other; + switch (verdict) { case __SK_PASS: sk_other = psock->sk; @@ -707,25 +737,8 @@ static void sk_psock_verdict_apply(struct sk_psock *psock, } goto out_free; case __SK_REDIRECT: - sk_other = tcp_skb_bpf_redirect_fetch(skb); - if (unlikely(!sk_other)) - goto out_free; - psock_other = sk_psock(sk_other); - if (!psock_other || sock_flag(sk_other, SOCK_DEAD) || - !sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED)) - goto out_free; - ingress = tcp_skb_bpf_ingress(skb); - if ((!ingress && sock_writeable(sk_other)) || - (ingress && - atomic_read(&sk_other->sk_rmem_alloc) <= - sk_other->sk_rcvbuf)) { - if (!ingress) - skb_set_owner_w(skb, sk_other); - skb_queue_tail(&psock_other->ingress_skb, skb); - schedule_work(&psock_other->work); - break; - } - /* fall-through */ + sk_psock_skb_redirect(psock, skb); + break; case __SK_DROP: /* fall-through */ default: -- cgit v1.2.3 From e91de6afa81c10e9f855c5695eb9a53168d96b73 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Fri, 29 May 2020 16:06:59 -0700 Subject: bpf: Fix running sk_skb program types with ktls KTLS uses a stream parser to collect TLS messages and send them to the upper layer tls receive handler. This ensures the tls receiver has a full TLS header to parse when it is run. However, when a socket has BPF_SK_SKB_STREAM_VERDICT program attached before KTLS is enabled we end up with two stream parsers running on the same socket. The result is both try to run on the same socket. First the KTLS stream parser runs and calls read_sock() which will tcp_read_sock which in turn calls tcp_rcv_skb(). This dequeues the skb from the sk_receive_queue. When this is done KTLS code then data_ready() callback which because we stacked KTLS on top of the bpf stream verdict program has been replaced with sk_psock_start_strp(). This will in turn kick the stream parser again and eventually do the same thing KTLS did above calling into tcp_rcv_skb() and dequeuing a skb from the sk_receive_queue. At this point the data stream is broke. Part of the stream was handled by the KTLS side some other bytes may have been handled by the BPF side. Generally this results in either missing data or more likely a "Bad Message" complaint from the kTLS receive handler as the BPF program steals some bytes meant to be in a TLS header and/or the TLS header length is no longer correct. We've already broke the idealized model where we can stack ULPs in any order with generic callbacks on the TX side to handle this. So in this patch we do the same thing but for RX side. We add a sk_psock_strp_enabled() helper so TLS can learn a BPF verdict program is running and add a tls_sw_has_ctx_rx() helper so BPF side can learn there is a TLS ULP on the socket. Then on BPF side we omit calling our stream parser to avoid breaking the data stream for the KTLS receiver. Then on the KTLS side we call BPF_SK_SKB_STREAM_VERDICT once the KTLS receiver is done with the packet but before it posts the msg to userspace. This gives us symmetry between the TX and RX halfs and IMO makes it usable again. On the TX side we process packets in this order BPF -> TLS -> TCP and on the receive side in the reverse order TCP -> TLS -> BPF. Discovered while testing OpenSSL 3.0 Alpha2.0 release. Fixes: d829e9c4112b5 ("tls: convert to generic sk_msg interface") Signed-off-by: John Fastabend Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/159079361946.5745.605854335665044485.stgit@john-Precision-5820-Tower Signed-off-by: Alexei Starovoitov --- include/linux/skmsg.h | 8 ++++++++ include/net/tls.h | 9 +++++++++ net/core/skmsg.c | 43 ++++++++++++++++++++++++++++++++++++++++--- net/tls/tls_sw.c | 20 ++++++++++++++++++-- 4 files changed, 75 insertions(+), 5 deletions(-) (limited to 'net/core/skmsg.c') diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h index ad31c9fb7158..08674cd14d5a 100644 --- a/include/linux/skmsg.h +++ b/include/linux/skmsg.h @@ -437,4 +437,12 @@ static inline void psock_progs_drop(struct sk_psock_progs *progs) psock_set_prog(&progs->skb_verdict, NULL); } +int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb); + +static inline bool sk_psock_strp_enabled(struct sk_psock *psock) +{ + if (!psock) + return false; + return psock->parser.enabled; +} #endif /* _LINUX_SKMSG_H */ diff --git a/include/net/tls.h b/include/net/tls.h index 3e7b44cae0d9..3212d3c214a9 100644 --- a/include/net/tls.h +++ b/include/net/tls.h @@ -571,6 +571,15 @@ static inline bool tls_sw_has_ctx_tx(const struct sock *sk) return !!tls_sw_ctx_tx(ctx); } +static inline bool tls_sw_has_ctx_rx(const struct sock *sk) +{ + struct tls_context *ctx = tls_get_ctx(sk); + + if (!ctx) + return false; + return !!tls_sw_ctx_rx(ctx); +} + void tls_sw_write_space(struct sock *sk, struct tls_context *ctx); void tls_device_write_space(struct sock *sk, struct tls_context *ctx); diff --git a/net/core/skmsg.c b/net/core/skmsg.c index 9d72f71e9b47..351afbf6bfba 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -7,6 +7,7 @@ #include #include +#include static bool sk_msg_try_coalesce_ok(struct sk_msg *msg, int elem_first_coalesce) { @@ -714,6 +715,38 @@ static void sk_psock_skb_redirect(struct sk_psock *psock, struct sk_buff *skb) } } +static void sk_psock_tls_verdict_apply(struct sk_psock *psock, + struct sk_buff *skb, int verdict) +{ + switch (verdict) { + case __SK_REDIRECT: + sk_psock_skb_redirect(psock, skb); + break; + case __SK_PASS: + case __SK_DROP: + default: + break; + } +} + +int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb) +{ + struct bpf_prog *prog; + int ret = __SK_PASS; + + rcu_read_lock(); + prog = READ_ONCE(psock->progs.skb_verdict); + if (likely(prog)) { + tcp_skb_bpf_redirect_clear(skb); + ret = sk_psock_bpf_run(psock, prog, skb); + ret = sk_psock_map_verd(ret, tcp_skb_bpf_redirect_fetch(skb)); + } + rcu_read_unlock(); + sk_psock_tls_verdict_apply(psock, skb, ret); + return ret; +} +EXPORT_SYMBOL_GPL(sk_psock_tls_strp_read); + static void sk_psock_verdict_apply(struct sk_psock *psock, struct sk_buff *skb, int verdict) { @@ -792,9 +825,13 @@ static void sk_psock_strp_data_ready(struct sock *sk) rcu_read_lock(); psock = sk_psock(sk); if (likely(psock)) { - write_lock_bh(&sk->sk_callback_lock); - strp_data_ready(&psock->parser.strp); - write_unlock_bh(&sk->sk_callback_lock); + if (tls_sw_has_ctx_rx(sk)) { + psock->parser.saved_data_ready(sk); + } else { + write_lock_bh(&sk->sk_callback_lock); + strp_data_ready(&psock->parser.strp); + write_unlock_bh(&sk->sk_callback_lock); + } } rcu_read_unlock(); } diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index 8c2763eb6aae..24f64bc0de18 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -1742,6 +1742,7 @@ int tls_sw_recvmsg(struct sock *sk, long timeo; bool is_kvec = iov_iter_is_kvec(&msg->msg_iter); bool is_peek = flags & MSG_PEEK; + bool bpf_strp_enabled; int num_async = 0; int pending; @@ -1752,6 +1753,7 @@ int tls_sw_recvmsg(struct sock *sk, psock = sk_psock_get(sk); lock_sock(sk); + bpf_strp_enabled = sk_psock_strp_enabled(psock); /* Process pending decrypted records. It must be non-zero-copy */ err = process_rx_list(ctx, msg, &control, &cmsg, 0, len, false, @@ -1805,11 +1807,12 @@ int tls_sw_recvmsg(struct sock *sk, if (to_decrypt <= len && !is_kvec && !is_peek && ctx->control == TLS_RECORD_TYPE_DATA && - prot->version != TLS_1_3_VERSION) + prot->version != TLS_1_3_VERSION && + !bpf_strp_enabled) zc = true; /* Do not use async mode if record is non-data */ - if (ctx->control == TLS_RECORD_TYPE_DATA) + if (ctx->control == TLS_RECORD_TYPE_DATA && !bpf_strp_enabled) async_capable = ctx->async_capable; else async_capable = false; @@ -1859,6 +1862,19 @@ int tls_sw_recvmsg(struct sock *sk, goto pick_next_record; if (!zc) { + if (bpf_strp_enabled) { + err = sk_psock_tls_strp_read(psock, skb); + if (err != __SK_PASS) { + rxm->offset = rxm->offset + rxm->full_len; + rxm->full_len = 0; + if (err == __SK_DROP) + consume_skb(skb); + ctx->recv_pkt = NULL; + __strp_unpause(&ctx->strp); + continue; + } + } + if (rxm->full_len > len) { retain_skb = true; chunk = len; -- cgit v1.2.3