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| author | Eric Dumazet <edumazet@google.com> | 2012-07-17 10:13:05 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-07-17 01:36:20 -0700 |
| commit | 282f23c6ee343126156dd41218b22ece96d747e3 (patch) | |
| tree | 9a306d99ed77d760078d29699edd3007507d709b /Documentation/networking | |
| parent | a858d64b7709ca7bd2ee71d66ef3b7190cdcbb7d (diff) | |
| download | linux-282f23c6ee343126156dd41218b22ece96d747e3.tar.gz | |
tcp: implement RFC 5961 3.2
Implement the RFC 5691 mitigation against Blind Reset attack using RST bit. Idea is to validate incoming RST sequence, to match RCV.NXT value, instead of previouly accepted window : (RCV.NXT <= SEG.SEQ < RCV.NXT+RCV.WND) If sequence is in window but not an exact match, send a "challenge ACK", so that the other part can resend an RST with the appropriate sequence. Add a new sysctl, tcp_challenge_ack_limit, to limit number of challenge ACK sent per second. Add a new SNMP counter to count number of challenge acks sent. (netstat -s | grep TCPChallengeACK) Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Kiran Kumar Kella <kkiran@broadcom.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/networking')
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index e20c17a7d34e..e1e021594cff 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -565,6 +565,11 @@ tcp_limit_output_bytes - INTEGER reduce the size of individual GSO packet (64KB being the max) Default: 131072 +tcp_challenge_ack_limit - INTEGER + Limits number of Challenge ACK sent per second, as recommended + in RFC 5961 (Improving TCP's Robustness to Blind In-Window Attacks) + Default: 100 + UDP variables: udp_mem - vector of 3 INTEGERs: min, pressure, max |