[PATCH v2] samples/landlock: Fix possible NULL dereference in parse_path()

[Mickaël Salaün]

Thanks! I've simplified a bit your patch and pushed it to my next tree.

On Wed, Nov 27, 2024 at 09:29:56PM -0600, Gax-c wrote:
> From: Zichen Xie <zichenxie0106 at gmail.com>
> 
> malloc() may return NULL, leading to NULL dereference.
> Add a NULL check.
> 
> Fixes: ba84b0bf5a16 ("samples/landlock: Add a sandbox manager example")
> Signed-off-by: Zichen Xie <zichenxie0106 at gmail.com>
> Cc: stable at vger.kernel.org
> ---
> v2: Modify logic & Add Fixes tag.
> ---
>  samples/landlock/sandboxer.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
> index 57565dfd74a2..ef2a34173d84 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;
> +
>  	for (i = 0; i < num_paths; i++)
>  		(*path_list)[i] = strsep(&env_path, ENV_DELIMITER);
>  
> @@ -127,6 +130,11 @@ static int populate_ruleset_fs(const char *const env_var, const int ruleset_fd,
>  	env_path_name = strdup(env_path_name);
>  	unsetenv(env_var);
>  	num_paths = parse_path(env_path_name, &path_list);
> +	if (num_paths == -1) {
> +		fprintf(stderr, "Failed to allocate memory\n");
> +		ret = 1;
> +		goto out_free_name;
> +	}
>  	if (num_paths == 1 && path_list[0][0] == '\0') {
>  		/*
>  		 * Allows to not use all possible restrictions (e.g. use
> -- 
> 2.34.1
> 
>