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authorEric Dumazet <edumazet@google.com>2020-10-15 11:42:00 -0700
committerJakub Kicinski <kuba@kernel.org>2020-10-16 16:47:09 -0700
commitb38e7819cae946e2edf869e604af1e65a5d241c5 (patch)
tree3950efd4431d1dfa82b181415329aac165e48d50 /Documentation/networking/ip-sysctl.rst
parent137d23cea1c044b2d4853ac71bc68126b25fdbb2 (diff)
downloadlinux-b38e7819cae946e2edf869e604af1e65a5d241c5.tar.bz2
icmp: randomize the global rate limiter
Keyu Man reported that the ICMP rate limiter could be used by attackers to get useful signal. Details will be provided in an upcoming academic publication. Our solution is to add some noise, so that the attackers no longer can get help from the predictable token bucket limiter. Fixes: 4cdf507d5452 ("icmp: add a global rate limitation") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Keyu Man <kman001@ucr.edu> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'Documentation/networking/ip-sysctl.rst')
-rw-r--r--Documentation/networking/ip-sysctl.rst4
1 files changed, 3 insertions, 1 deletions
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index 837d51f9e1fa..25e6673a085a 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -1142,13 +1142,15 @@ icmp_ratelimit - INTEGER
icmp_msgs_per_sec - INTEGER
Limit maximal number of ICMP packets sent per second from this host.
Only messages whose type matches icmp_ratemask (see below) are
- controlled by this limit.
+ controlled by this limit. For security reasons, the precise count
+ of messages per second is randomized.
Default: 1000
icmp_msgs_burst - INTEGER
icmp_msgs_per_sec controls number of ICMP packets sent per second,
while icmp_msgs_burst controls the burst size of these packets.
+ For security reasons, the precise burst size is randomized.
Default: 50