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 <[email protected]> > --- > 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 <[email protected]> Suggested-by: Eric Dumazet <[email protected]> Acked-by: Eric Dumazet <[email protected]> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
