From 3f05010f243be06478a9b11cfce0ce994f5a0890 Mon Sep 17 00:00:00 2001
From: Aidan MacDonald <aidanmacdonald.0x0@gmail.com>
Date: Mon, 20 Jun 2022 21:05:57 +0100
Subject: [PATCH] regmap-irq: Fix offset/index mismatch in read_sub_irq_data()
Git-commit: 3f05010f243be06478a9b11cfce0ce994f5a0890
Patch-mainline: v5.19-rc4
References: git-fixes

We need to divide the sub-irq status register offset by register
stride to get an index for the status buffer to avoid an out of
bounds write when the register stride is greater than 1.

Fixes: a2d21848d921 ("regmap: regmap-irq: Add main status register support")
Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@gmail.com>
Link: https://lore.kernel.org/r/20220620200644.1961936-3-aidanmacdonald.0x0@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/base/regmap/regmap-irq.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/base/regmap/regmap-irq.c b/drivers/base/regmap/regmap-irq.c
index 4f785bc7981c..a6db605707b0 100644
--- a/drivers/base/regmap/regmap-irq.c
+++ b/drivers/base/regmap/regmap-irq.c
@@ -387,6 +387,7 @@ static inline int read_sub_irq_data(struct regmap_irq_chip_data *data,
 		subreg = &chip->sub_reg_offsets[b];
 		for (i = 0; i < subreg->num_regs; i++) {
 			unsigned int offset = subreg->offset[i];
+			unsigned int index = offset / map->reg_stride;
 
 			if (chip->not_fixed_stride)
 				ret = regmap_read(map,
@@ -395,7 +396,7 @@ static inline int read_sub_irq_data(struct regmap_irq_chip_data *data,
 			else
 				ret = regmap_read(map,
 						chip->status_base + offset,
-						&data->status_buf[offset]);
+						&data->status_buf[index]);
 
 			if (ret)
 				break;
-- 
2.35.3