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-rw-r--r--recipes-kernel/linux/files/CVE-2016-5696-limiting-of-all-challenge.patch109
1 files changed, 0 insertions, 109 deletions
diff --git a/recipes-kernel/linux/files/CVE-2016-5696-limiting-of-all-challenge.patch b/recipes-kernel/linux/files/CVE-2016-5696-limiting-of-all-challenge.patch
deleted file mode 100644
index f2c2364..0000000
--- a/recipes-kernel/linux/files/CVE-2016-5696-limiting-of-all-challenge.patch
+++ /dev/null
@@ -1,109 +0,0 @@
1From 5413f1a526d2d51d7a5768133c90936c017165c6 Mon Sep 17 00:00:00 2001
2From: Jason Baron <jbaron@akamai.com>
3Date: Thu, 14 Jul 2016 11:38:40 -0400
4Subject: [PATCH] tcp: enable per-socket rate limiting of all 'challenge acks'
5
6[ Upstream commit 083ae308280d13d187512b9babe3454342a7987e ]
7
8The per-socket rate limit for 'challenge acks' was introduced in the
9context of limiting ack loops:
10
11commit f2b2c582e824 ("tcp: mitigate ACK loops for connections as tcp_sock")
12
13And I think it can be extended to rate limit all 'challenge acks' on a
14per-socket basis.
15
16Since we have the global tcp_challenge_ack_limit, this patch allows for
17tcp_challenge_ack_limit to be set to a large value and effectively rely on
18the per-socket limit, or set tcp_challenge_ack_limit to a lower value and
19still prevents a single connections from consuming the entire challenge ack
20quota.
21
22It further moves in the direction of eliminating the global limit at some
23point, as Eric Dumazet has suggested. This a follow-up to:
24Subject: tcp: make challenge acks less predictable
25
26CVE: CVE-2016-5696
27Upstream-Status: Backport
28
29Cc: Eric Dumazet <edumazet@google.com>
30Cc: David S. Miller <davem@davemloft.net>
31Cc: Neal Cardwell <ncardwell@google.com>
32Cc: Yuchung Cheng <ycheng@google.com>
33Cc: Yue Cao <ycao009@ucr.edu>
34Signed-off-by: Jason Baron <jbaron@akamai.com>
35Signed-off-by: David S. Miller <davem@davemloft.net>
36Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
37Signed-off-by: Sona Sarmadi <sona.sarmadi@enea.com>
38---
39 net/ipv4/tcp_input.c | 39 ++++++++++++++++++++++-----------------
40 1 file changed, 22 insertions(+), 17 deletions(-)
41
42diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
43index 05f10df..12b98e2 100644
44--- a/net/ipv4/tcp_input.c
45+++ b/net/ipv4/tcp_input.c
46@@ -3390,6 +3390,23 @@ static int tcp_ack_update_window(struct sock *sk, const struct sk_buff *skb, u32
47 return flag;
48 }
49
50+static bool __tcp_oow_rate_limited(struct net *net, int mib_idx,
51+ u32 *last_oow_ack_time)
52+{
53+ if (*last_oow_ack_time) {
54+ s32 elapsed = (s32)(tcp_time_stamp - *last_oow_ack_time);
55+
56+ if (0 <= elapsed && elapsed < sysctl_tcp_invalid_ratelimit) {
57+ NET_INC_STATS_BH(net, mib_idx);
58+ return true; /* rate-limited: don't send yet! */
59+ }
60+ }
61+
62+ *last_oow_ack_time = tcp_time_stamp;
63+
64+ return false; /* not rate-limited: go ahead, send dupack now! */
65+}
66+
67 /* Return true if we're currently rate-limiting out-of-window ACKs and
68 * thus shouldn't send a dupack right now. We rate-limit dupacks in
69 * response to out-of-window SYNs or ACKs to mitigate ACK loops or DoS
70@@ -3403,21 +3420,9 @@ bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb,
71 /* Data packets without SYNs are not likely part of an ACK loop. */
72 if ((TCP_SKB_CB(skb)->seq != TCP_SKB_CB(skb)->end_seq) &&
73 !tcp_hdr(skb)->syn)
74- goto not_rate_limited;
75-
76- if (*last_oow_ack_time) {
77- s32 elapsed = (s32)(tcp_time_stamp - *last_oow_ack_time);
78-
79- if (0 <= elapsed && elapsed < sysctl_tcp_invalid_ratelimit) {
80- NET_INC_STATS_BH(net, mib_idx);
81- return true; /* rate-limited: don't send yet! */
82- }
83- }
84-
85- *last_oow_ack_time = tcp_time_stamp;
86+ return false;
87
88-not_rate_limited:
89- return false; /* not rate-limited: go ahead, send dupack now! */
90+ return __tcp_oow_rate_limited(net, mib_idx, last_oow_ack_time);
91 }
92
93 /* RFC 5961 7 [ACK Throttling] */
94@@ -3430,9 +3435,9 @@ static void tcp_send_challenge_ack(struct sock *sk, const struct sk_buff *skb)
95 u32 count, now;
96
97 /* First check our per-socket dupack rate limit. */
98- if (tcp_oow_rate_limited(sock_net(sk), skb,
99- LINUX_MIB_TCPACKSKIPPEDCHALLENGE,
100- &tp->last_oow_ack_time))
101+ if (__tcp_oow_rate_limited(sock_net(sk),
102+ LINUX_MIB_TCPACKSKIPPEDCHALLENGE,
103+ &tp->last_oow_ack_time))
104 return;
105
106 /* Then check host-wide RFC 5961 rate limit. */
107--
1081.9.1
109