From mboxrd@z Thu Jan  1 00:00:00 1970
Subject: Re: [Patch 1/3] Loadable policy module infrastructure
From: Joshua Brindle <jbrindle@tresys.com>
To: Stephen Smalley <sds@tycho.nsa.gov>
Cc: selinux <selinux@tycho.nsa.gov>, selinux-dev@tresys.com
In-Reply-To: <1117564703.28924.243.camel@moss-spartans.epoch.ncsc.mil>
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	 <1117564703.28924.243.camel@moss-spartans.epoch.ncsc.mil>
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Date: Tue, 31 May 2005 15:28:33 -0400
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On Tue, 2005-05-31 at 14:38 -0400, Stephen Smalley wrote:
> On Thu, 2005-05-26 at 13:27 -0400, Joshua Brindle wrote:
> > diff -burNd a1/libsepol/src/util.c b/libsepol/src/util.c
> > --- a1/libsepol/src/util.c	1969-12-31 19:00:00.000000000 -0500
> > +++ b/libsepol/src/util.c	2005-05-25 13:11:19.488060776 -0400
> > +int type_set_or(type_set_t *dst, type_set_t *a, type_set_t *b)
> > +{
> > +        type_set_init(dst);
> > +
> > +        if (ebitmap_or(&dst->types, &a->types, &b->types)) {
> > +                fprintf(stderr, "Memory error\n");
> > +                return -1;
> > +        }
> > +        if (ebitmap_or(&dst->negset, &a->negset, &b->negset)) {
> > +                fprintf(stderr, "Memory error\n");
> > +                return -1;
> > +        }
> > +
> > +        dst->flags |= a->flags;
> > +        dst->flags |= b->flags;
> > +
> > +        return 0;
> > +}
> 
> I don't see any users of this function or even an exported function
> prototype for it (or for a number of other functions), but am uncertain
> about its semantics if it is going to be used.  The simple or'ing of the
> negset and flags means that:
> - anything excluded from either set will be excluded from the result
> even if it was present in the other set,
> - if either set is a set complement, then the result will be the
> complement of the union.
> 
> That's quite different from an ebitmap_or() of the expanded type sets.
> 

You are right, the semantics of this are funny, this is used in the
linking code to essentially copy avrules from modules to the base. The
best thing to do is probably get rid of this or function and replace it
with a copy function so that we don't run into bugs.

Joshua


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