[PATCH] mtd: spi-nor: sfdp: Fix out of bound array access

[PATCH] mtd: spi-nor: sfdp: Fix out of bound array access

[Mathieu Dubois-Briand]

Fix array index: explicitly use the array length to access the last
element, instead of an incorrectly set iteration variable.

It seems this code was correct before following commit, were the
iteration counter is reused, leading to a value that may be out of
bound.
Fixes: dc92843159a7 ("mtd: spi-nor: fix erase_type array to indicate
current map conf")

Signed-off-by: Mathieu Dubois-Briand <mbriand@witekio.com>
---
 drivers/mtd/spi-nor/sfdp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c
index 6ee7719e5903..11cc5d19e286 100644
--- a/drivers/mtd/spi-nor/sfdp.c
+++ b/drivers/mtd/spi-nor/sfdp.c
@@ -881,7 +881,7 @@ spi_nor_init_non_uniform_erase_map(struct spi_nor *nor,
 		if (!(regions_erase_type & BIT(erase[i].idx)))
 			spi_nor_set_erase_type(&erase[i], 0, 0xFF);
 
-	spi_nor_region_mark_end(&region[i - 1]);
+	spi_nor_region_mark_end(&region[region_count - 1]);
 
 	return 0;
 }
-- 
2.25.1

Re: [PATCH] mtd: spi-nor: sfdp: Fix out of bound array access

[Pratyush Yadav]

On 12/02/21 04:47PM, Mathieu Dubois-Briand wrote:
> Fix array index: explicitly use the array length to access the last
> element, instead of an incorrectly set iteration variable.
> 
> It seems this code was correct before following commit, were the
> iteration counter is reused, leading to a value that may be out of
> bound.
> Fixes: dc92843159a7 ("mtd: spi-nor: fix erase_type array to indicate
> current map conf")
> 
> Signed-off-by: Mathieu Dubois-Briand <mbriand@witekio.com>
> ---
>  drivers/mtd/spi-nor/sfdp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c
> index 6ee7719e5903..11cc5d19e286 100644
> --- a/drivers/mtd/spi-nor/sfdp.c
> +++ b/drivers/mtd/spi-nor/sfdp.c
> @@ -881,7 +881,7 @@ spi_nor_init_non_uniform_erase_map(struct spi_nor *nor,
>  		if (!(regions_erase_type & BIT(erase[i].idx)))
>  			spi_nor_set_erase_type(&erase[i], 0, 0xFF);
>  
> -	spi_nor_region_mark_end(&region[i - 1]);
> +	spi_nor_region_mark_end(&region[region_count - 1]);

I'm not too familiar with the non-uniform erase code but this looks good 
at first look. Small nitpick: move this line just after the above for 
loop that initializes this array.

>  
>  	return 0;
>  }
> -- 
> 2.25.1
> 
> 
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/

-- 
Regards,
Pratyush Yadav
Texas Instruments Inc.

Re: [PATCH] mtd: spi-nor: sfdp: Fix out of bound array access

[Mathieu Dubois-Briand]

Hi,

I just came across this commit (9166f4af32db) in spi-nor/for-5.12:
https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git/commit/?h=spi-nor/for-5.12&id=9166f4af32db74e1544a2149aef231ff24515ea3.

So I believe this patch isn't needed anymore.

Thanks,
Mathieu

Re: [PATCH] mtd: spi-nor: sfdp: Fix out of bound array access

[Tudor.Ambarus]

On 2/19/21 9:50 AM, Mathieu Dubois-Briand wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> Hi,
> 
> I just came across this commit (9166f4af32db) in spi-nor/for-5.12:
> https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git/commit/?h=spi-nor/for-5.12&id=9166f4af32db74e1544a2149aef231ff24515ea3.
> 
> So I believe this patch isn't needed anymore.
> 

That's true. Thanks,
ta