#13731: Fix libsingular memory management
---------------------------+------------------------------------------------
Reporter: nbruin | Owner: rlm
Type: defect | Status: new
Priority: major | Milestone: sage-5.6
Component: memleak | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
---------------------------+------------------------------------------------
Comment (by nbruin):
> {{{
> ==30816== Invalid read of size 4
> ==30816== at 0x269CE137: rOrd_is_Totaldegree_Ordering(sip_sring*)
(ring.cc:2074)
> ...
> }}}
This is like shooting fish in a barrel. `ring.cc:157`:
{{{
...
int *order = (int *) omAlloc(2* sizeof(int));
...
return rDefault(ch,N,n,2,order,block0,block1);
}}}
calling `ring.cc:127` (the variable `order` above gets passed as the
parameter `ord` in the code below):
{{{
ring r=(ring) omAlloc0Bin(sip_sring_bin);
...
r->order = ord;
...
rComplete(r);
}}}
calling `ring.cc:3469`:
{{{
if (rOrd_is_Totaldegree_Ordering(r) ||
rOrd_is_WeightedDegree_Ordering(r))
}}}
calling `ring.cc:2065`:
{{{
BOOLEAN rOrd_is_Totaldegree_Ordering(ring r)
{
// Hmm.... what about Syz orderings?
return (rVar(r) > 1 &&
((rHasSimpleOrder(r) &&
(rOrder_is_DegOrdering((rRingOrder_t)r->order[0]) ||
rOrder_is_DegOrdering(( rRingOrder_t)r->order[1]))) ||
(rHasSimpleOrderAA(r) &&
(rOrder_is_DegOrdering((rRingOrder_t)r->order[1]) ||
rOrder_is_DegOrdering((rRingOrder_t)r->order[2])))));
}
}}}
As you see, that last line `...r->ord[2]` is indeed out of bound on a
`2*sizeof(int)` block. The valgrind session seems to indicate this code
path is indeed exercised.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13731#comment:33>
Sage <http://www.sagemath.org>
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