Messages in this thread | | | Subject | Re: [PATCH] net: check net.core.somaxconn sysctl values | From | Eric Dumazet <> | Date | Wed, 31 Jul 2013 07:37:37 -0700 |
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On Wed, 2013-07-31 at 17:57 +0400, Roman Gushchin wrote: > It's possible to assign an invalid value to the net.core.somaxconn > sysctl variable, because there is no checks at all. > > The sk_max_ack_backlog field of the sock structure is defined as > unsigned short. Therefore, the backlog argument in inet_listen() > shouldn't exceed USHRT_MAX. The backlog argument in the listen() syscall > is truncated to the somaxconn value. So, the somaxconn value shouldn't > exceed 65535 (USHRT_MAX). > Also, negative values of somaxconn are meaningless. > > before: > $ sysctl -w net.core.somaxconn=256 > net.core.somaxconn = 256 > $ sysctl -w net.core.somaxconn=65536 > net.core.somaxconn = 65536 > $ sysctl -w net.core.somaxconn=-100 > net.core.somaxconn = -100 > > after: > $ sysctl -w net.core.somaxconn=256 > net.core.somaxconn = 256 > $ sysctl -w net.core.somaxconn=65536 > error: "Invalid argument" setting key "net.core.somaxconn" > $ sysctl -w net.core.somaxconn=-100 > error: "Invalid argument" setting key "net.core.somaxconn" > > Signed-off-by: Roman Gushchin <klamm@yandex-team.ru> > --- > net/core/sysctl_net_core.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-)
We had a discussion about this one month ago, as Changli Gao posted a patch. http://patchwork.ozlabs.org/patch/255460/
So proper credits would be nice ;)
Based on a prior patch from Changli Gao
Reported-by: Changli Gao <xiaosuo@gmail.com> Suggested-by: Eric Dumazet <edumazet@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
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