[PATCH mtd-utils] misc-utils: flash_erase: FIX integer overflow in flash_erase.c

[PATCH mtd-utils] misc-utils: flash_erase: FIX integer overflow in flash_erase.c

[Anton Moryakov]

Report of the static analyzer:
The value of an arithmetic expression 'eb_cnt * mtd.eb_size' is a subject to overflow because its operands are not cast to a larger data type before performing arithmetic

Corrections explained:
Added explicit casting of eb_cnt to long long in the condition 
if (eb_start == 0 && mtd.size == eb_cnt * mtd.eb_size) 
to ensure the multiplication is performed in a 64-bit context, 
preventing potential overflow for large values of eb_cnt and mtd.eb_size.
This ensures correct handling of devices with large block counts or block sizes.

Triggers found by static analyzer Svace.

Signed-off-by: Anton Moryakov <ant.v.moryakov@gmail.com>

---
 misc-utils/flash_erase.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/misc-utils/flash_erase.c b/misc-utils/flash_erase.c
index c6f6f66..78a3bd1 100644
--- a/misc-utils/flash_erase.c
+++ b/misc-utils/flash_erase.c
@@ -239,7 +239,7 @@ int main(int argc, char *argv[])
 	if (eb_cnt == 0)
 		eb_cnt = (mtd.size / mtd.eb_size) - eb_start;
 
-	if (eb_start == 0 && mtd.size == eb_cnt * mtd.eb_size)
+	if (eb_start == 0 && mtd.size == (long long)eb_cnt * mtd.eb_size)
 		erase_chip = true;
 
 	/* If MTD device may have bad eraseblocks,
-- 
2.30.2


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Re: [PATCH mtd-utils] misc-utils: flash_erase: FIX integer overflow in flash_erase.c

[Zhihao Cheng]

在 2024/12/11 22:04, Anton Moryakov 写道:
> Report of the static analyzer:
> The value of an arithmetic expression 'eb_cnt * mtd.eb_size' is a subject to overflow because its operands are not cast to a larger data type before performing arithmetic
> 
> Corrections explained:
> Added explicit casting of eb_cnt to long long in the condition
> if (eb_start == 0 && mtd.size == eb_cnt * mtd.eb_size)
> to ensure the multiplication is performed in a 64-bit context,
> preventing potential overflow for large values of eb_cnt and mtd.eb_size.
> This ensures correct handling of devices with large block counts or block sizes.
> 
> Triggers found by static analyzer Svace.
> 
> Signed-off-by: Anton Moryakov <ant.v.moryakov@gmail.com>
> 
> ---
>   misc-utils/flash_erase.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
> 
> diff --git a/misc-utils/flash_erase.c b/misc-utils/flash_erase.c
> index c6f6f66..78a3bd1 100644
> --- a/misc-utils/flash_erase.c
> +++ b/misc-utils/flash_erase.c
> @@ -239,7 +239,7 @@ int main(int argc, char *argv[])
>   	if (eb_cnt == 0)
>   		eb_cnt = (mtd.size / mtd.eb_size) - eb_start;
>   
> -	if (eb_start == 0 && mtd.size == eb_cnt * mtd.eb_size)
> +	if (eb_start == 0 && mtd.size == (long long)eb_cnt * mtd.eb_size)
>   		erase_chip = true;
>   
>   	/* If MTD device may have bad eraseblocks,
> 


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