[dpdk-dev] [PATCH v2] ring: fix use after free in ring release
Konstantin Ananyev
konstantin.v.ananyev at yandex.ru
Mon May 1 14:32:28 CEST 2023
> After the memzone is freed, it is not removed from the 'rte_ring_tailq'.
> If rte_ring_lookup is called at this time, it will cause a use-after-free
> problem. This change prevents that from happening.
>
> Fixes: 4e32101f9b01 ("ring: support freeing")
> Cc: stable at dpdk.org
>
> Suggested-by: Honnappa Nagarahalli <honnappa.nagarahalli at arm.com>
> Signed-off-by: Yunjian Wang <wangyunjian at huawei.com>
> ---
> v2: update code suggested by Honnappa Nagarahalli
> ---
> lib/ring/rte_ring.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/lib/ring/rte_ring.c b/lib/ring/rte_ring.c
> index 8ed455043d..2755323b8a 100644
> --- a/lib/ring/rte_ring.c
> +++ b/lib/ring/rte_ring.c
> @@ -333,11 +333,6 @@ rte_ring_free(struct rte_ring *r)
> return;
> }
>
> - if (rte_memzone_free(r->memzone) != 0) {
> - RTE_LOG(ERR, RING, "Cannot free memory\n");
> - return;
> - }
> -
> ring_list = RTE_TAILQ_CAST(rte_ring_tailq.head, rte_ring_list);
> rte_mcfg_tailq_write_lock();
>
> @@ -354,6 +349,9 @@ rte_ring_free(struct rte_ring *r)
>
> TAILQ_REMOVE(ring_list, te, next);
>
> + if (rte_memzone_free(r->memzone) != 0)
> + RTE_LOG(ERR, RING, "Cannot free memory\n");
> +
I nit: I think it is a bit better to first release the lock and
then free the memzone.
Apart from that, LGTM.
Acked-by: Konstantin Ananyev <konstantin.v.ananyev at yandex.ru>
> rte_mcfg_tailq_write_unlock();
>
> rte_free(te);
> --
> 2.33.0
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