Re: strange pam_selinux behavior

[Dominick Grift <dac.override@gmail.com>]

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On 03/24/2016 02:14 PM, Miroslav Grepl wrote:

<snip>

>> 
>> added the access vector back in but that seems to not make any
>> differenc e.
> 
> So you are still getting the same error message, right?
> 

not quite right:

It now longer shows this: "Failed to translate security class context"

So that part seems to have been fixed by adding the access vector

however this error is still the same:

> pam_selinux(sshd:session): Security context
> wheel.id:wheel.role:wheel.subj:s0-s0:c0.c1023 is not allowed for
> wheel.id:wheel.role:wheel.s ubj:s0-s0:c0.c1023 Mar 24 13:43:03 void
> sshd[14723]: pam_selinux(sshd:session): Unable to get valid context
> for kcinimod

So looking at the code:

> src_context = context_new (src); dst_context = context_new (dst); 
> context_range_set(dst_context, context_range_get(src_context)); if
> (debug) pam_syslog(pamh, LOG_NOTICE, "Checking if %s mls range
> valid for  %s", dst, context_str(dst_context));
> 
> retval = security_compute_av(context_str(dst_context), dst, class,
> bit, &avd); context_free(src_context); context_free(dst_context); 
> if (retval || ((bit & avd.allowed) != bit)) return 0;
> 
> return 1;

it appears that security_compute_av returns bad. But i can't figure
out how to reproduce that with "compute_av":

# compute_av wheel.id:wheel.role:wheel.subj:s0-s0:c0.c1023
wheel.id:wheel.role:wheel.subj:s0-s0:c0.c1023 process

allowed = { fork sigchld sigkill signull signal getsched setsched
setpgid getattr setfscreate }

This works fine with stock fedora policy BTW. this seems to be a DSSP
specific issue. I am wondering if my policy has a bug somewhere...


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Dominick Grift
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