diff options
Diffstat (limited to 'target/linux/generic/backport-5.4/080-wireguard-0106-wireguard-queueing-preserve-flow-hash-across-packet-.patch')
| -rw-r--r-- | target/linux/generic/backport-5.4/080-wireguard-0106-wireguard-queueing-preserve-flow-hash-across-packet-.patch | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/target/linux/generic/backport-5.4/080-wireguard-0106-wireguard-queueing-preserve-flow-hash-across-packet-.patch b/target/linux/generic/backport-5.4/080-wireguard-0106-wireguard-queueing-preserve-flow-hash-across-packet-.patch new file mode 100644 index 0000000000..31deadbfc1 --- /dev/null +++ b/target/linux/generic/backport-5.4/080-wireguard-0106-wireguard-queueing-preserve-flow-hash-across-packet-.patch @@ -0,0 +1,116 @@ +From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 +From: "Jason A. Donenfeld" <Jason@zx2c4.com> +Date: Tue, 19 May 2020 22:49:29 -0600 +Subject: [PATCH] wireguard: queueing: preserve flow hash across packet + scrubbing +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +commit c78a0b4a78839d572d8a80f6a62221c0d7843135 upstream. + +It's important that we clear most header fields during encapsulation and +decapsulation, because the packet is substantially changed, and we don't +want any info leak or logic bug due to an accidental correlation. But, +for encapsulation, it's wrong to clear skb->hash, since it's used by +fq_codel and flow dissection in general. Without it, classification does +not proceed as usual. This change might make it easier to estimate the +number of innerflows by examining clustering of out of order packets, +but this shouldn't open up anything that can't already be inferred +otherwise (e.g. syn packet size inference), and fq_codel can be disabled +anyway. + +Furthermore, it might be the case that the hash isn't used or queried at +all until after wireguard transmits the encrypted UDP packet, which +means skb->hash might still be zero at this point, and thus no hash +taken over the inner packet data. In order to address this situation, we +force a calculation of skb->hash before encrypting packet data. + +Of course this means that fq_codel might transmit packets slightly more +out of order than usual. Toke did some testing on beefy machines with +high quantities of parallel flows and found that increasing the +reply-attack counter to 8192 takes care of the most pathological cases +pretty well. + +Reported-by: Dave Taht <dave.taht@gmail.com> +Reviewed-and-tested-by: Toke Høiland-Jørgensen <toke@toke.dk> +Fixes: e7096c131e51 ("net: WireGuard secure network tunnel") +Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> +Signed-off-by: David S. Miller <davem@davemloft.net> +Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> +--- + drivers/net/wireguard/messages.h | 2 +- + drivers/net/wireguard/queueing.h | 10 +++++++++- + drivers/net/wireguard/receive.c | 2 +- + drivers/net/wireguard/send.c | 7 ++++++- + 4 files changed, 17 insertions(+), 4 deletions(-) + +--- a/drivers/net/wireguard/messages.h ++++ b/drivers/net/wireguard/messages.h +@@ -32,7 +32,7 @@ enum cookie_values { + }; + + enum counter_values { +- COUNTER_BITS_TOTAL = 2048, ++ COUNTER_BITS_TOTAL = 8192, + COUNTER_REDUNDANT_BITS = BITS_PER_LONG, + COUNTER_WINDOW_SIZE = COUNTER_BITS_TOTAL - COUNTER_REDUNDANT_BITS + }; +--- a/drivers/net/wireguard/queueing.h ++++ b/drivers/net/wireguard/queueing.h +@@ -87,12 +87,20 @@ static inline bool wg_check_packet_proto + return real_protocol && skb->protocol == real_protocol; + } + +-static inline void wg_reset_packet(struct sk_buff *skb) ++static inline void wg_reset_packet(struct sk_buff *skb, bool encapsulating) + { ++ u8 l4_hash = skb->l4_hash; ++ u8 sw_hash = skb->sw_hash; ++ u32 hash = skb->hash; + skb_scrub_packet(skb, true); + memset(&skb->headers_start, 0, + offsetof(struct sk_buff, headers_end) - + offsetof(struct sk_buff, headers_start)); ++ if (encapsulating) { ++ skb->l4_hash = l4_hash; ++ skb->sw_hash = sw_hash; ++ skb->hash = hash; ++ } + skb->queue_mapping = 0; + skb->nohdr = 0; + skb->peeked = 0; +--- a/drivers/net/wireguard/receive.c ++++ b/drivers/net/wireguard/receive.c +@@ -484,7 +484,7 @@ int wg_packet_rx_poll(struct napi_struct + if (unlikely(wg_socket_endpoint_from_skb(&endpoint, skb))) + goto next; + +- wg_reset_packet(skb); ++ wg_reset_packet(skb, false); + wg_packet_consume_data_done(peer, skb, &endpoint); + free = false; + +--- a/drivers/net/wireguard/send.c ++++ b/drivers/net/wireguard/send.c +@@ -167,6 +167,11 @@ static bool encrypt_packet(struct sk_buf + struct sk_buff *trailer; + int num_frags; + ++ /* Force hash calculation before encryption so that flow analysis is ++ * consistent over the inner packet. ++ */ ++ skb_get_hash(skb); ++ + /* Calculate lengths. */ + padding_len = calculate_skb_padding(skb); + trailer_len = padding_len + noise_encrypted_len(0); +@@ -295,7 +300,7 @@ void wg_packet_encrypt_worker(struct wor + skb_list_walk_safe(first, skb, next) { + if (likely(encrypt_packet(skb, + PACKET_CB(first)->keypair))) { +- wg_reset_packet(skb); ++ wg_reset_packet(skb, true); + } else { + state = PACKET_STATE_DEAD; + break; |