[PATCH AUTOSEL 4.19 49/64] s390/qeth: fix use-after-free in error path

Sasha Levin
2019-02-28T15:23:40Z

From: Julian Wiedmann <jwi@linux.ibm.com>

[ Upstream commit afa0c5904ba16d59b0454f7ee4c807dae350f432 ]

The error path in qeth_alloc_qdio_buffers() that takes care of
cleaning up the Output Queues is buggy. It first frees the queue, but
then calls qeth_clear_outq_buffers() with that very queue struct.

Make the call to qeth_clear_outq_buffers() part of the free action
(in the correct order), and while at it fix the naming of the helper.

Fixes: 0da9581ddb0f ("qeth: exploit asynchronous delivery of storage blocks")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/s390/net/qeth_core_main.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 4b3b9c4e46d2a..56aacf32f71b0 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -2454,11 +2454,12 @@ static int qeth_init_qdio_out_buf(struct qeth_qdio_out_q *q, int bidx)
return 0;
}

-static void qeth_free_qdio_out_buf(struct qeth_qdio_out_q *q)
+static void qeth_free_output_queue(struct qeth_qdio_out_q *q)
{
if (!q)
return;

+ qeth_clear_outq_buffers(q, 1);
qdio_free_buffers(q->qdio_bufs, QDIO_MAX_BUFFERS_PER_Q);
kfree(q);
}
@@ -2532,10 +2533,8 @@ static int qeth_alloc_qdio_buffers(struct qeth_card *card)
card->qdio.out_qs[i]->bufs[j] = NULL;
}
out_freeoutq:
- while (i > 0) {
- qeth_free_qdio_out_buf(card->qdio.out_qs[--i]);
- qeth_clear_outq_buffers(card->qdio.out_qs[i], 1);
- }
+ while (i > 0)
+ qeth_free_output_queue(card->qdio.out_qs[--i]);
kfree(card->qdio.out_qs);
card->qdio.out_qs = NULL;
out_freepool:
@@ -2568,10 +2567,8 @@ static void qeth_free_qdio_buffers(struct qeth_card *card)
qeth_free_buffer_pool(card);
/* free outbound qdio_qs */
if (card->qdio.out_qs) {
- for (i = 0; i < card->qdio.no_out_queues; ++i) {
- qeth_clear_outq_buffers(card->qdio.out_qs[i], 1);
- qeth_free_qdio_out_buf(card->qdio.out_qs[i]);
- }
+ for (i = 0; i < card->qdio.no_out_queues; i++)
+ qeth_free_output_queue(card->qdio.out_qs[i]);
kfree(card->qdio.out_qs);
card->qdio.out_qs = NULL;
}
--
2.19.1