Re: [PATCH] net: check net.core.somaxconn sysctl values

[Roman Gushchin]

On 03.08.2013 02:19, David Miller wrote:
> From: Roman Gushchin <klamm@xxxxxxxxxxxxxx>
> Date: Fri,  2 Aug 2013 18:36:40 +0400
>
> > 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"
> >
> > Based on a prior patch from Changli Gao.
> >
> > Signed-off-by: Roman Gushchin <klamm@xxxxxxxxxxxxxx>
> > Reported-by: Changli Gao <xiaosuo@xxxxxxxxx>
> > Suggested-by: Eric Dumazet <edumazet@xxxxxxxxxx>
> > Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx>
>
> Applied, thanks.

Thank you!

Regards,
Roman

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