[PATCH] FIX: NO_CAST.INTEGER_OVERFLOW in ubirsvol.c

[Zhihao Cheng]

在 2024/12/6 20:37, Anton Moryakov 写道:
> Report of the static analyzer:
> The value of an arithmetic expression 'vol_info.leb_size * args.lebs' is a subject to overflow because its operands are not cast to a larger data type before performing arithmetic
> 
> Corrections explained:
> the fix ensures values ​​are checked before multiplication.
> an exception check for the negativity of vol_info.leb_size and args.lebs was added, as well as casting vol_info.leb_size to uint64_t
> 
> Triggers found by static analyzer Svace.
> 
> Signed-off-by: Anton Moryakov <ant.v.moryakov at gmail.com>
> 
> ---
>   ubi-utils/ubirsvol.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)

Hi Anton. Please make the title be something like '[PATCH mtd-utils] 
ubi-utils: ubirsvol: Fix integer overflow ...'.
> 
> diff --git a/ubi-utils/ubirsvol.c b/ubi-utils/ubirsvol.c
> index 0854abc..87286d4 100644
> --- a/ubi-utils/ubirsvol.c
> +++ b/ubi-utils/ubirsvol.c
> @@ -230,8 +230,10 @@ int main(int argc, char * const argv[])
>   		}
>   	}
>   
> -	if (args.lebs != -1)
> -		args.bytes = vol_info.leb_size * args.lebs;
> +	if (args.lebs != -1){
> +		if(vol_info.leb_size > 0 && args.lebs > 0)
> +			args.bytes =(uint64_t)vol_info.leb_size * args.lebs;
> +	}

The 'args.bytes' is a long long type value and will be parsed as s64 in 
ioctl(UBI_IOCRSVOL), so we should convert the type as 'long long' or 
'int64_t'.
The 'vol_info.leb_size' and 'args.lebs' are guaranteed to be positive 
numbers by ubi_get_vol_info1() and parse_opt(), so we can write this like:
if (args.lebs != -1)
	args.bytes = (long long)vol_info.leb_size * args.lebs;

>   
>   	err = ubi_rsvol(libubi, args.node, args.vol_id, args.bytes);
>   	if (err) {
>