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

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@gmail.com>
Link: https://lore.kernel.org/r/20241128032955.11711-1-zichenxie0106@gmail.com
[mic: Simplify fix]
Signed-off-by: Mickaël Salaün <mic@digikod.net>

diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
index 57565dfd74a260f7b436d6587682ca93f6180c13..07fab2ef534e8d854f17e39ab3d8da42b2f2ad81 100644 (file)
--- 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)
+               return -1;
+
        for (i = 0; i < num_paths; i++)
                (*path_list)[i] = strsep(&env_path, ENV_DELIMITER);
 
@@ -127,6 +130,10 @@ 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 < 0) {
+               fprintf(stderr, "Failed to allocate memory\n");
+               goto out_free_name;
+       }
        if (num_paths == 1 && path_list[0][0] == '\0') {
                /*
                 * Allows to not use all possible restrictions (e.g. use