Hi Jeff-
> On Mar 30, 2023, at 2:24 PM, Jeff Layton <jlayton@xxxxxxxxxx> wrote:
>
> While the unix_gid object is rcu-freed, the group_info list that it
> contains is not. Ensure that we only put the group list reference once
> we are really freeing the unix_gid object.
>
> Reported-by: Zhi Li <yieli@xxxxxxxxxx>
Should we also add
Fixes: fd5d2f78261b ("SUNRPC: Make server side AUTH_UNIX use lockless lookups") ?
> Link: https://bugzilla.redhat.com/show_bug.cgi?id=2183056
This bug isn't publicly accessible, fwiw.
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> net/sunrpc/svcauth_unix.c | 17 +++++++++++++----
> 1 file changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
> index 50e2eb579194..4485088ce27b 100644
> --- a/net/sunrpc/svcauth_unix.c
> +++ b/net/sunrpc/svcauth_unix.c
> @@ -416,14 +416,23 @@ static int unix_gid_hash(kuid_t uid)
> return hash_long(from_kuid(&init_user_ns, uid), GID_HASHBITS);
> }
>
> -static void unix_gid_put(struct kref *kref)
> +static void unix_gid_free(struct rcu_head *rcu)
> {
> - struct cache_head *item = container_of(kref, struct cache_head, ref);
> - struct unix_gid *ug = container_of(item, struct unix_gid, h);
> + struct unix_gid *ug = container_of(rcu, struct unix_gid, rcu);
> + struct cache_head *item = &ug->h;
> +
> if (test_bit(CACHE_VALID, &item->flags) &&
> !test_bit(CACHE_NEGATIVE, &item->flags))
> put_group_info(ug->gi);
> - kfree_rcu(ug, rcu);
> + kfree(ug);
> +}
> +
> +static void unix_gid_put(struct kref *kref)
> +{
> + struct cache_head *item = container_of(kref, struct cache_head, ref);
> + struct unix_gid *ug = container_of(item, struct unix_gid, h);
> +
> + call_rcu(&ug->rcu, unix_gid_free);
> }
>
> static int unix_gid_match(struct cache_head *corig, struct cache_head *cnew)
> --
> 2.39.2
>
--
Chuck Lever
