[PATCH] net: fealnx: fixed possible out of band acces to an array

[PATCH] net: fealnx: fixed possible out of band acces to an array

[Ilya Krutskih]

fixed possible out of band access to an array 
If the fealnx_init_one() function is called more than MAX_UNITS times 
or card_idx is less than zero

Added a check: 0 <= card_idx < MAX_UNITS

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Ilya Krutskih <devsec@tpz.ru>
---
 drivers/net/ethernet/fealnx.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/fealnx.c b/drivers/net/ethernet/fealnx.c
index 6ac8547ef9b8..c7f2141a01fe 100644
--- a/drivers/net/ethernet/fealnx.c
+++ b/drivers/net/ethernet/fealnx.c
@@ -491,8 +491,8 @@ static int fealnx_init_one(struct pci_dev *pdev,
 
 	card_idx++;
 	sprintf(boardname, "fealnx%d", card_idx);
-
-	option = card_idx < MAX_UNITS ? options[card_idx] : 0;
+	if (card_idx >= 0)
+		option = card_idx < MAX_UNITS ? options[card_idx] : 0;
 
 	i = pci_enable_device(pdev);
 	if (i) return i;
@@ -623,7 +623,7 @@ static int fealnx_init_one(struct pci_dev *pdev,
 		np->default_port = option & 15;
 	}
 
-	if (card_idx < MAX_UNITS && full_duplex[card_idx] > 0)
+	if ((0 <= card_idx && MAX_UNITS > card_idx) && full_duplex[card_idx] > 0)
 		np->mii.full_duplex = full_duplex[card_idx];
 
 	if (np->mii.full_duplex) {
-- 
2.43.0

Re: [PATCH] net: fealnx: fixed possible out of band acces to an array

[kernel test robot]

Hi,

Thanks for your patch.

FYI: kernel test robot notices the stable kernel rule is not satisfied.

The check is based on https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html#option-1

Rule: add the tag "Cc: stable@vger.kernel.org" in the sign-off area to have the patch automatically included in the stable tree.
Subject: [PATCH] net: fealnx: fixed possible out of band acces to an array
Link: https://lore.kernel.org/stable/20251110134423.432612-1-devsec%40tpz.ru

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH] net: fealnx: fixed possible out of band acces to an array

[I Viswanath]

On 10/11/25 19:14, Ilya Krutskih wrote:
> fixed possible out of band access to an array
> If the fealnx_init_one() function is called more than MAX_UNITS times
> or card_idx is less than zero

The code already validates against the >= MAX_UNITS case and card_idx
can never be less than zero at those points under normal circumstances, making
this patch unnecessary.

However, card_idx will overflow with enough calls and that is something
that should probably be fixed