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From:   Aidan MacDonald <aidanmacdonald.0x0@gmail.com>
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Subject: [PATCH 02/49] regmap-irq: Fix offset/index mismatch in read_sub_irq_data()
Date:   Mon, 20 Jun 2022 21:05:57 +0100
Message-Id: <20220620200644.1961936-3-aidanmacdonald.0x0@gmail.com>
In-Reply-To: <20220620200644.1961936-1-aidanmacdonald.0x0@gmail.com>
References: <20220620200644.1961936-1-aidanmacdonald.0x0@gmail.com>
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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>
---
 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;
-- 
2.35.1