release/5.2.40/net-ena-fix-corruption-of-dev_idx_to_host_tbl.patch

From 3ef7c40127d36155d7ce06804a6134de2da6c148 Mon Sep 17 00:00:00 2001
From: Arthur Kiyanovski <akiyano@amazon.com>
Date: Tue, 11 Feb 2020 15:17:48 +0000
Subject: [PATCH] net: ena: fix corruption of dev_idx_to_host_tbl

commit e3f89f91e98ce07dc0f121a3b70d21aca749ba39 upstream.

The function ena_com_ind_tbl_convert_from_device() has an overflow
bug as explained below. Either way, this function is not needed at
all since we don't retrieve the indirection table from the device
at any point which means that this conversion is not needed.

The bug:
The for loop iterates over all io_sq_queues, when passing the actual
number of used queues the io_sq_queues[i].idx equals 0 since they are
uninitialized which results in the following code to be executed till
the end of the loop:

dev_idx_to_host_tbl[0] = i;

This results dev_idx_to_host_tbl[0] in being equal to
ENA_TOTAL_NUM_QUEUES - 1.

Fixes: 1738cd3ed342 ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)")
Signed-off-by: Sameeh Jubran <sameehj@amazon.com>
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/net/ethernet/amazon/ena/ena_com.c b/drivers/net/ethernet/amazon/ena/ena_com.c
index 11c68e80699d..afe05e8a0096 100644
--- a/drivers/net/ethernet/amazon/ena/ena_com.c
+++ b/drivers/net/ethernet/amazon/ena/ena_com.c
@@ -1261,30 +1261,6 @@ static int ena_com_ind_tbl_convert_to_device(struct ena_com_dev *ena_dev)
 	return 0;
 }
 
-static int ena_com_ind_tbl_convert_from_device(struct ena_com_dev *ena_dev)
-{
-	u16 dev_idx_to_host_tbl[ENA_TOTAL_NUM_QUEUES] = { (u16)-1 };
-	struct ena_rss *rss = &ena_dev->rss;
-	u8 idx;
-	u16 i;
-
-	for (i = 0; i < ENA_TOTAL_NUM_QUEUES; i++)
-		dev_idx_to_host_tbl[ena_dev->io_sq_queues[i].idx] = i;
-
-	for (i = 0; i < 1 << rss->tbl_log_size; i++) {
-		if (rss->rss_ind_tbl[i].cq_idx > ENA_TOTAL_NUM_QUEUES)
-			return -EINVAL;
-		idx = (u8)rss->rss_ind_tbl[i].cq_idx;
-
-		if (dev_idx_to_host_tbl[idx] > ENA_TOTAL_NUM_QUEUES)
-			return -EINVAL;
-
-		rss->host_rss_ind_tbl[i] = dev_idx_to_host_tbl[idx];
-	}
-
-	return 0;
-}
-
 static int ena_com_init_interrupt_moderation_table(struct ena_com_dev *ena_dev)
 {
 	size_t size;
@@ -2602,10 +2578,6 @@ int ena_com_indirect_table_get(struct ena_com_dev *ena_dev, u32 *ind_tbl)
 	if (!ind_tbl)
 		return 0;
 
-	rc = ena_com_ind_tbl_convert_from_device(ena_dev);
-	if (unlikely(rc))
-		return rc;
-
 	for (i = 0; i < (1 << rss->tbl_log_size); i++)
 		ind_tbl[i] = rss->host_rss_ind_tbl[i];
 
-- 
2.7.4