[PATCH] samples/landlock: Fix possible NULL dereference in parse_path()

[Mickaël Salaün]

On Tue, Nov 26, 2024 at 12:41:57PM -0600, Gax-c wrote:
> From: Zichen Xie <zichenxie0106 at gmail.com>
> 
> malloc() may return NULL, leading to NULL dereference.
> Add a NULL check.
> 
> Signed-off-by: Zichen Xie <zichenxie0106 at gmail.com>
> ---
>  samples/landlock/sandboxer.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
> index 57565dfd74a2..385fc115647f 100644
> --- a/samples/landlock/sandboxer.c
> +++ b/samples/landlock/sandboxer.c
> @@ -91,6 +91,9 @@ static int parse_path(char *env_path, const char ***const path_list)
>  		}
>  	}
>  	*path_list = malloc(num_paths * sizeof(**path_list));
> +	if (*path_list == NULL)
> +		return 1;

This creates another NULL deference in the caller.

We should print to stderr to explain the issue, return -1, and update
the caller to check for this error.

> +
>  	for (i = 0; i < num_paths; i++)
>  		(*path_list)[i] = strsep(&env_path, ENV_DELIMITER);
>  
> -- 
> 2.34.1
> 
>