Re: [PATCH mtd-utils] ubi-utils: Fix integer overflow in mtdinfo.c

[Zhihao Cheng <chengzhihao1@huawei.com>]

在 2024/12/13 1:13, Anton Moryakov 写道:
> Report of the static analyzer:
> The value of an arithmetic expression 'reginfo->offset + i * reginfo->erasesize' is a subject to overflow
> because its operands are not cast to a larger data type before performing arithmetic
> 
> Corrections explained:
> Added casting reginfo->offset to long long
> 
> Triggers found by static analyzer Svace.
> 
> Signed-off-by: Anton Moryakov <ant.v.moryakov@gmail.com>
> 
> ---
>   ubi-utils/mtdinfo.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/ubi-utils/mtdinfo.c b/ubi-utils/mtdinfo.c
> index 7dff0de..850297b 100644
> --- a/ubi-utils/mtdinfo.c
> +++ b/ubi-utils/mtdinfo.c
> @@ -203,7 +203,7 @@ static void print_region_map(const struct mtd_dev_info *mtd, int fd,
>   		ret_locked = ret_bad = errno_locked = errno_bad = 0;
>   
>   	for (i = 0; i < reginfo->numblocks; ++i) {
> -		start = reginfo->offset + i * reginfo->erasesize;

Hi Anton.
I think the expression 'i*reginfo->erasesize' could overflow too. 
Besides, 'unsigned long start' could be a 32-bit number on a 32-bit 
platform.
So, we should make 'start' be the 'unsigned long long' type, and then 
convert 'i' into 'unsigned long long' in expression 'i * 
reginfo->erasesize'. For example, start = reginfo->offset + (unsigned 
long long)i * reginfo->erasesize.
> +		start = (long long)reginfo->offset + i * reginfo->erasesize;
>   		printf(" %*i: %08lx ", width, i, start);
>   
>   		if (ret_locked != -1) {
> 


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/