[hipl-dev] [Bug 790679] Re: Minor segfault on failed startup
- From: David Martin <790679@xxxxxxxxxxxxxxxxxx>
- To: hipl-dev@xxxxxxxxxxxxx
- Date: Fri, 03 Jun 2011 10:02:02 -0000
Hi,
> But ok, another option is to re-organize the initialization so that that
> variable gets set before it is possible to abort the initialization.
> Basically move the hip_xfrm_set_nl_ipsec() call to somewhere before the
> first HIP_IFEL.
>
> .. I'll attach a patch now that I actually tried it out.
I would say that moving the initialization only fixes the sympton and
not the problem. :) What if the initialization for what you are
uninitializing fails? It should be robust in any case! In addition the
documentation states that hip_xfrm_set_nl_ipsec() gets an initialized
netlink socket. If you move this call further forward it will definitely
not get an initialized socket because this happens in
rtnl_open_byproto() right before it.
What happens here is the following:
We have got a rtnl_handle struct to store the field descriptor and sequence
number and stuff for our netlink socket. It is static and located in hipd.c.
Our IPsec implementation is in xfrmapi.c and has no direct access to it. What
it has instead is a static pointer that gets pointed to the handle struct in
the initialization. This does not happen if anything in the initialization
already fails before.
The problem here is not really the uninitialization. The null pointer
gets passed through all functions that try to remove the default
policies that would usually be set up on startup. We could do sanity
checks on the pointers in these functions or in the exit call like Miika
proposes but this should not really be necessary. In most cases the
sockets are correctly initialized and it does not really matter for the
calls.
As it turns out netlink_talk() that sends messages on the netlink
sockets is not robust. It assumes to get a valid netlink socket and as a
consequence segfaults if it doesn't. This is what happens here. I have
committed a fix in trunk revision 5950.
Jookos, please check if it works for you.
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https://bugs.launchpad.net/bugs/790679
Title:
Minor segfault on failed startup
Status in Host Identity Protocol for Linux:
New
Bug description:
If the kernel module checks during startup fails, hipd segfaults
instead of exiting nicely. This because the hip_xfrmapi_nl_ipsec
(lib/tool/xfrmapi.c:49) hasn't been initialized before it is used in
hip_delete_hit_sp_pair() [which is called on exit].
quick & dirty patch attached
Other related posts:
