Per family bind/unbind callbacks were introduced to allow families to track multicast group consumer presence, e.g. to start or stop producing events depending on listeners. However, in genl_bind() the bind() callback was invoked even if capability checks failed and ret was set to -EPERM. This means that callbacks could run on behalf of unauthorized callers while the syscall still returned failure to user space. Fix this by only invoking bind() after "if (ret) break;" check i.e. after permission checks have succeeded. Fixes: 3de21a8990d3 ("genetlink: Add per family bind/unbind callbacks") Signed-off-by: Alok Tiwari --- v1 -> v2 replace if (!ret && family->bind) with separate "if (ret) break;" as suggested by Jabuk. https://lore.kernel.org/all/20250831190315.1280502-1-alok.a.tiwari@oracle.com/ --- net/netlink/genetlink.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index 104732d34543..978c129c6095 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -1836,6 +1836,9 @@ static int genl_bind(struct net *net, int group) !ns_capable(net->user_ns, CAP_SYS_ADMIN)) ret = -EPERM; + if (ret) + break; + if (family->bind) family->bind(i); -- 2.50.1