Bad bug in remote logging

Linda Knippers linda.knippers at hp.com
Tue Apr 12 03:18:44 UTC 2011


Steve Grubb wrote:
> Hello,
> 
> There was a bug reported to day that I think merits an email and/or discussion.
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=695419
> =================================
> audisp-remote does
>>               memset (&address, 0, sizeof(address));
>>               address.sin_family = htons(AF_INET);
>>               address.sin_port = htons(config.local_port);
>>               address.sin_addr.s_addr = htonl(INADDR_ANY);
> which shows in strace as
> 
>> bind(3, {sa_family=0x200 /* AF_??? */, sa_data="\0<\0\0\0\0\0\0\0\0\0\0\0\0"}, 16) = 
> 0
> 
> For some reason the call still succeeds, but a correct invocation would not
> call htons on AF_INET.

Are you sure that that field is actually used by bind()?  Doesn't the
socket also have the address family?  Its surprising that the call would
succeed and even more surprising that the socket would work.

> ================================
> 
> The reason it succeeds is because there is a matching mistake in auditd. So, what this 
> means is that remote logging is not using IPv4, but something else. 

What else would it be using?  That value is greater than any legal 
address family so I would think that lots of things in the kernel
would break.

> I committed a 
> patch to fix this in trunk:
> 
> https://fedorahosted.org/audit/changeset/505
> 
> This would cause new systems and old systems to not be able to talk to one another. 
> Regarding RHEL, remote logging has been tech preview, meaning that its alpha code and 
> likely buggy but available so you can see where this is heading. So, I think we can 
> just change it to be correct. For Fedora, there is no tech preview and everything is 
> supported...but it has a short life. However, what the code was doing is clearly 
> wrong. So, I am thinking to fix this all the way back to F-13 if I can. Regarding other 
> distributions...not sure what the support status is or how they would like to choose 
> to solve this. Anyone have any thoughts on this?

Your resolution seems ok if this is really more than a benign coding
problem.

-- ljk

> 
> -Steve
> 
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