[PATCH] lib: sbi: Fix potential garbage data in string copy functions

[Xiang W]

在 2025-02-19三的 09:57 +0800，zhangdongdong at eswincomputing.com写道：
> From: Dongdong Zhang <zhangdongdong at eswincomputing.com>
> 
> In the original implementation of `sbi_strcpy` and `sbi_strncpy`, if the
> destination buffer (`dest`) was longer than the source string (`src`),
> the functions did not ensure that the remaining bytes in `dest` were
> properly null-terminated. This could result in garbage data being
> present in the destination buffer after the copy operation, as the
> functions only copied characters from `src` without explicitly
> terminating `dest`.
> 
LGTM

Reviewed-by: Xiang W <wxjstz at 126.com>

> Signed-off-by: Dongdong Zhang <zhangdongdong at eswincomputing.com>
> ---
>  lib/sbi/sbi_string.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/lib/sbi/sbi_string.c b/lib/sbi/sbi_string.c
> index 9ebea69..f4f1394 100644
> --- a/lib/sbi/sbi_string.c
> +++ b/lib/sbi/sbi_string.c
> @@ -68,22 +68,22 @@ char *sbi_strcpy(char *dest, const char *src)
>  {
>  	char *ret = dest;
>  
> -	while (*src != '\0') {
> -		*dest++ = *src++;
> +	while ((*dest++ = *src++) != '\0') {
>  	}
> -
>  	return ret;
>  }
>  
>  char *sbi_strncpy(char *dest, const char *src, size_t count)
>  {
> -	char *ret = dest;
> +	char *tmp = dest;
>  
> -	while (count-- && *src != '\0') {
> -		*dest++ = *src++;
> +	while (count) {
> +		if ((*tmp = *src) != 0)
> +			src++;
> +		tmp++;
> +		count--;
>  	}
> -
> -	return ret;
> +	return dest;
>  }
>  
>  char *sbi_strchr(const char *s, int c)
> -- 
> 2.17.1
> 
>