pid: use struct_size_t() helper
Commit Message
Before commit d67790ddf021 ("overflow: Add struct_size_t() helper") only
struct_size() existed, which expects a valid pointer instance containing
the flexible array.
However, when we determine the default struct pid allocation size for
the associated kmem cache of a pid namespace we need to take the nesting
depth of the pid namespace into account without an variable instance
necessarily being available.
In commit b69f0aeb0689 ("pid: Replace struct pid 1-element array with
flex-array") we used to handle this the old fashioned way and cast NULL
to a struct pid pointer type. However, we do apparently have a dedicated
struct_size_t() helper for exactly this case. So switch to that.
Suggested-by: Kees Cook <keescook@chromium.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
kernel/pid.c | 2 +-
kernel/pid_namespace.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
base-commit: a507db1d8fdc39802415e4d2ef6d1aecd67927fa
Comments
On Fri, 30 Jun 2023 at 23:45, Christian Brauner <brauner@kernel.org> wrote:
>
> [..] However, we do apparently have a dedicated
> struct_size_t() helper for exactly this case. So switch to that.
Applied,
Linus
@@ -657,7 +657,7 @@ void __init pid_idr_init(void)
idr_init(&init_pid_ns.idr);
init_pid_ns.pid_cachep = kmem_cache_create("pid",
- struct_size((struct pid *)NULL, numbers, 1),
+ struct_size_t(struct pid, numbers, 1),
__alignof__(struct pid),
SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT,
NULL);
@@ -48,7 +48,7 @@ static struct kmem_cache *create_pid_cachep(unsigned int level)
return kc;
snprintf(name, sizeof(name), "pid_%u", level + 1);
- len = struct_size((struct pid *)NULL, numbers, level + 1);
+ len = struct_size_t(struct pid, numbers, level + 1);
mutex_lock(&pid_caches_mutex);
/* Name collision forces to do allocation under mutex. */
if (!*pkc)