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196f3d586f
5.4.102 backported a lot of stuff that our WireGuard backport already did, in addition to other patches we had, so those patches were removed from that part of the series. In the process other patches were refreshed or reworked to account for upstream changes. This commit involved `update_kernel.sh -v -u 5.4`. Cc: John Audia <graysky@archlinux.us> Cc: David Bauer <mail@david-bauer.net> Cc: Petr Štetiar <ynezz@true.cz> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
117 lines
4.3 KiB
Diff
117 lines
4.3 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: "Jason A. Donenfeld" <Jason@zx2c4.com>
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Date: Tue, 19 May 2020 22:49:29 -0600
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Subject: [PATCH] wireguard: queueing: preserve flow hash across packet
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scrubbing
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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commit c78a0b4a78839d572d8a80f6a62221c0d7843135 upstream.
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It's important that we clear most header fields during encapsulation and
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decapsulation, because the packet is substantially changed, and we don't
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want any info leak or logic bug due to an accidental correlation. But,
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for encapsulation, it's wrong to clear skb->hash, since it's used by
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fq_codel and flow dissection in general. Without it, classification does
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not proceed as usual. This change might make it easier to estimate the
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number of innerflows by examining clustering of out of order packets,
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but this shouldn't open up anything that can't already be inferred
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otherwise (e.g. syn packet size inference), and fq_codel can be disabled
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anyway.
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Furthermore, it might be the case that the hash isn't used or queried at
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all until after wireguard transmits the encrypted UDP packet, which
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means skb->hash might still be zero at this point, and thus no hash
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taken over the inner packet data. In order to address this situation, we
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force a calculation of skb->hash before encrypting packet data.
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Of course this means that fq_codel might transmit packets slightly more
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out of order than usual. Toke did some testing on beefy machines with
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high quantities of parallel flows and found that increasing the
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reply-attack counter to 8192 takes care of the most pathological cases
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pretty well.
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Reported-by: Dave Taht <dave.taht@gmail.com>
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Reviewed-and-tested-by: Toke Høiland-Jørgensen <toke@toke.dk>
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Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
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Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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---
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drivers/net/wireguard/messages.h | 2 +-
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drivers/net/wireguard/queueing.h | 10 +++++++++-
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drivers/net/wireguard/receive.c | 2 +-
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drivers/net/wireguard/send.c | 7 ++++++-
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4 files changed, 17 insertions(+), 4 deletions(-)
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--- a/drivers/net/wireguard/messages.h
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+++ b/drivers/net/wireguard/messages.h
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@@ -32,7 +32,7 @@ enum cookie_values {
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};
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enum counter_values {
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- COUNTER_BITS_TOTAL = 2048,
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+ COUNTER_BITS_TOTAL = 8192,
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COUNTER_REDUNDANT_BITS = BITS_PER_LONG,
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COUNTER_WINDOW_SIZE = COUNTER_BITS_TOTAL - COUNTER_REDUNDANT_BITS
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};
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--- a/drivers/net/wireguard/queueing.h
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+++ b/drivers/net/wireguard/queueing.h
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@@ -87,12 +87,20 @@ static inline bool wg_check_packet_proto
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return real_protocol && skb->protocol == real_protocol;
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}
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-static inline void wg_reset_packet(struct sk_buff *skb)
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+static inline void wg_reset_packet(struct sk_buff *skb, bool encapsulating)
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{
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+ u8 l4_hash = skb->l4_hash;
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+ u8 sw_hash = skb->sw_hash;
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+ u32 hash = skb->hash;
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skb_scrub_packet(skb, true);
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memset(&skb->headers_start, 0,
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offsetof(struct sk_buff, headers_end) -
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offsetof(struct sk_buff, headers_start));
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+ if (encapsulating) {
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+ skb->l4_hash = l4_hash;
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+ skb->sw_hash = sw_hash;
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+ skb->hash = hash;
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+ }
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skb->queue_mapping = 0;
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skb->nohdr = 0;
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skb->peeked = 0;
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--- a/drivers/net/wireguard/receive.c
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+++ b/drivers/net/wireguard/receive.c
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@@ -484,7 +484,7 @@ int wg_packet_rx_poll(struct napi_struct
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if (unlikely(wg_socket_endpoint_from_skb(&endpoint, skb)))
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goto next;
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- wg_reset_packet(skb);
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+ wg_reset_packet(skb, false);
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wg_packet_consume_data_done(peer, skb, &endpoint);
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free = false;
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--- a/drivers/net/wireguard/send.c
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+++ b/drivers/net/wireguard/send.c
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@@ -167,6 +167,11 @@ static bool encrypt_packet(struct sk_buf
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struct sk_buff *trailer;
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int num_frags;
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+ /* Force hash calculation before encryption so that flow analysis is
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+ * consistent over the inner packet.
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+ */
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+ skb_get_hash(skb);
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+
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/* Calculate lengths. */
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padding_len = calculate_skb_padding(skb);
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trailer_len = padding_len + noise_encrypted_len(0);
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@@ -295,7 +300,7 @@ void wg_packet_encrypt_worker(struct wor
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skb_list_walk_safe(first, skb, next) {
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if (likely(encrypt_packet(skb,
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PACKET_CB(first)->keypair))) {
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- wg_reset_packet(skb);
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+ wg_reset_packet(skb, true);
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} else {
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state = PACKET_STATE_DEAD;
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break;
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