Re: [PATCH 1/5] util: Be more defensive about buffer overruns in read_file()

[Laurent Vivier <lvivier@redhat.com>]

On 1/5/26 08:53, David Gibson wrote:
> clang-21.1.7 complains about read_file(), thinking that total_read might
> come to exceed buf_size, leading to an out of bounds access at the end of
> the function.  In fact, the semantics of read()'s return mean this can't
> ever happen.  But we already have to check for the total_read == buf_size
> case, so it's basically free to change it to >= and suppress the error.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>   util.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/util.c b/util.c
> index 27303950..a48f727c 100644
> --- a/util.c
> +++ b/util.c
> @@ -715,7 +715,7 @@ static ssize_t read_file(const char *path, char *buf, size_t buf_size)
>   
>   	close(fd);
>   
> -	if (total_read == buf_size) {
> +	if (total_read >= buf_size) {
>   		buf[buf_size - 1] = '\0';
>   		return -ENOBUFS;
>   	}

Reviewed-by: Laurent Vivier <lvivier@redhat.com>