[PATCH v4] pinctrl: mediatek: fix global-out-of-bounds issue

[Zhiyong Tao]

From: Guodong Liu <guodong.liu at mediatek.corp-partner.google.com>

When eint virtual eint number is greater than gpio number,
it maybe produce 'desc[eint_n]' size globle-out-of-bounds issue.

Signed-off-by: Guodong Liu <guodong.liu at mediatek.corp-partner.google.com>
Signed-off-by: Zhiyong Tao <zhiyong.tao at mediatek.com>
Reviewed-by: Chen-Yu Tsai <wenst at chromium.org>
---
Changes in patch v4:
1. fix sort signed-off-by name.
2. add Reviewed-by.

Changes in patch v3:
1. keep original patch author
2. fix version issue.

Changes in patch v2:
1. change check eint number boundary condition.
---
 drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
index 45ebdeba985a..12163d3c4bcb 100644
--- a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
+++ b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
@@ -285,8 +285,12 @@ static int mtk_xt_get_gpio_n(void *data, unsigned long eint_n,
 	desc = (const struct mtk_pin_desc *)hw->soc->pins;
 	*gpio_chip = &hw->chip;
 
-	/* Be greedy to guess first gpio_n is equal to eint_n */
-	if (desc[eint_n].eint.eint_n == eint_n)
+	/*
+	 * Be greedy to guess first gpio_n is equal to eint_n.
+	 * Only eint virtual eint number is greater than gpio number.
+	 */
+	if (hw->soc->npins > eint_n &&
+	    desc[eint_n].eint.eint_n == eint_n)
 		*gpio_n = eint_n;
 	else
 		*gpio_n = mtk_xt_find_eint_num(hw, eint_n);
-- 
2.25.1