Skip to content

seccomp: fix n_plugins calculation #1956

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
giuseppe wants to merge 1 commit into
base: main
Choose a base branch
from
+32 −5
Open

seccomp: fix n_plugins calculation #1956

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 9 additions & 4 deletions src/libcrun/seccomp_notify.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -95,13 +95,17 @@ libcrun_load_seccomp_notify_plugins (struct seccomp_notify_context_s **out, cons
ctx->sreq = xmalloc (ctx->sizes.seccomp_notif);
ctx->sresp = xmalloc (ctx->sizes.seccomp_notif_resp);

if (is_empty_string (plugins))
return 0;

b = xstrdup (plugins);
Copy link

@gemini-code-assist gemini-code-assist bot Jan 16, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

critical

If plugins is NULL, xstrdup returns NULL, making b NULL. The loop at line 101 will then dereference this NULL pointer, causing a crash. You can prevent this by ensuring b is never NULL, for example by assigning it an empty string if xstrdup returns NULL. This would also make the behavior for NULL plugins consistent with an empty plugin string.

  b = xstrdup (plugins);
  if (!b)
    b = "";


ctx->n_plugins = 1;
for (it = b; it; it = strchr (it, ':'))
ctx->n_plugins++;
for (it = b; *it; it++)
if (*it == ':')
ctx->n_plugins++;

ctx->plugins = xmalloc0 (sizeof (struct plugin) * (ctx->n_plugins + 1));

b = xstrdup (plugins);
for (s = 0, it = strtok_r (b, ":", &saveptr); it; s++, it = strtok_r (NULL, ":", &saveptr))
{
run_oci_seccomp_notify_plugin_version_cb version_cb;
Expand Down Expand Up @@ -254,6 +258,7 @@ libcrun_free_seccomp_notify_plugins (struct seccomp_notify_context_s *ctx, libcr
dlclose (ctx->plugins[i].handle);
}

free (ctx->plugins);
free (ctx);

return 0;
Expand Down
24 changes: 23 additions & 1 deletion tests/tests_libcrun_seccomp_notify.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -114,6 +114,27 @@ test_load_nonexistent_plugin ()
return 0;
}

/* Test load with multiple non-existent plugins to verify cleanup of n_plugins. */
static int
test_load_multiple_nonexistent_plugins ()
{
libcrun_error_t err = NULL;
struct seccomp_notify_context_s *ctx = NULL;
int ret;

ret = libcrun_load_seccomp_notify_plugins (&ctx, "/nonexistent/p1.so:/nonexistent/p2.so:/nonexistent/p3.so", NULL, &err);
if (ret >= 0)
{
if (ctx)
libcrun_free_seccomp_notify_plugins (ctx, &err);
crun_error_release (&err);
return -1;
}

crun_error_release (&err);
return 0;
}

/* Test seccomp_notify_plugins returns error without seccomp support */
static int
test_notify_no_seccomp ()
Expand Down Expand Up @@ -167,11 +188,12 @@ int
main ()
{
int id = 1;
printf ("1..5\n");
printf ("1..6\n");
RUN_TEST (test_cleanup_null);
RUN_TEST (test_free_null_context);
RUN_TEST (test_load_invalid_path);
RUN_TEST (test_load_nonexistent_plugin);
RUN_TEST (test_load_multiple_nonexistent_plugins);
RUN_TEST (test_notify_no_seccomp);
return 0;
}