Potential memory leak of inherited local nexthop in ospfd

[johndoe2012]

Hello all,

we deployed frr8.1 and in our testing we detect memory leak in ospfd OSPF nexthop

OSPF nexthop                  :  3233230      8    25865840  3233238  25865904

It is still uncleared to us what scenario/ospf interaction triggers it, but preliminary code inspection and debugging link the memory leak to inherit local nexthop alloc https://github.com/FRRouting/frr/blob/master/ospfd/ospf_spf.c#L1135-L1142. it does not seem to be freed by ospf_spf_cleanup or anywhere. we are not sure how the local nexthop is been used by ti-lfa (we don't have it enabled) without dig into the code more.

can anyone with context shed some light on where such inherited local nexthop is supposed to be released?

Thank you,

[aceelindem]

There is, in fact, a memory leak here but it is fixed in later releases. The commit is:

commit b3bcfd3
Author: Rafael Zalamena [email protected]
Date: Mon Dec 12 15:11:27 2022 -0300

ospfd: fix memory leak on SPF calculation

Fix the following problems:
- Always free vertex next hops on `vertex_parent_free`
- Signalize failure on `ospf_spf_add_parent` when parent already exists
  so the caller has the chance to `free()` any allocated resources.
- Don't reuse vertex next hops without the reference count logic in
  `ospf_nexthop_calculation`. Instead allocate a new copy so it can be
  `free()`d later without complications

Signed-off-by: Rafael Zalamena <[email protected]>

I'd advise either moving to a later release or backporting the fix.

Thanks,
Acee