[PATCH v2] mtd: spi-nor: cast to u64 to avoid uint overflows

[Huijin Park]

From: "huijin.park" <***@samsung.com>

The "params->size" is defined as "u64".
And "info->sector_size" and "info->n_sectors" are defined as
unsigned int and u16.
Thus, u64 data might have strange data(loss data) if the result
overflows an unsigned int.
This patch casts "info->sector_size" and "info->n_sectors" to an u64.

Signed-off-by: huijin.park <***@samsung.com>
---
drivers/mtd/spi-nor/spi-nor.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index d9c368c..527f281 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -2459,7 +2459,7 @@ static int spi_nor_init_params(struct spi_nor *nor,
memset(params, 0, sizeof(*params));

/* Set SPI NOR sizes. */
- params->size = info->sector_size * info->n_sectors;
+ params->size = (u64)info->sector_size * (u64)info->n_sectors;
params->page_size = info->page_size;

/* (Fast) Read settings. */

[Geert Uytterhoeven]

Hi Huijin,

Post by Huijin Park
The "params->size" is defined as "u64".
And "info->sector_size" and "info->n_sectors" are defined as
unsigned int and u16.
Thus, u64 data might have strange data(loss data) if the result
overflows an unsigned int.
This patch casts "info->sector_size" and "info->n_sectors" to an u64.
---
drivers/mtd/spi-nor/spi-nor.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index d9c368c..527f281 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -2459,7 +2459,7 @@ static int spi_nor_init_params(struct spi_nor *nor,
memset(params, 0, sizeof(*params));
/* Set SPI NOR sizes. */
- params->size = info->sector_size * info->n_sectors;
+ params->size = (u64)info->sector_size * (u64)info->n_sectors;

Adding the cast to only the first operand should be sufficient, and may lead
to faster code, as only a 64x16 multiplication needs to be done, instead of
a 64x64.

Post by Huijin Park
params->page_size = info->page_size;
/* (Fast) Read settings. */

Gr{oetje,eeting}s,

Geert