From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/net/fib_notifier.h | 51 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 include/net/fib_notifier.h (limited to 'include/net/fib_notifier.h') diff --git a/include/net/fib_notifier.h b/include/net/fib_notifier.h new file mode 100644 index 000000000..48aad6128 --- /dev/null +++ b/include/net/fib_notifier.h @@ -0,0 +1,51 @@ +#ifndef __NET_FIB_NOTIFIER_H +#define __NET_FIB_NOTIFIER_H + +#include +#include +#include + +struct module; + +struct fib_notifier_info { + int family; + struct netlink_ext_ack *extack; +}; + +enum fib_event_type { + FIB_EVENT_ENTRY_REPLACE, + FIB_EVENT_ENTRY_APPEND, + FIB_EVENT_ENTRY_ADD, + FIB_EVENT_ENTRY_DEL, + FIB_EVENT_RULE_ADD, + FIB_EVENT_RULE_DEL, + FIB_EVENT_NH_ADD, + FIB_EVENT_NH_DEL, + FIB_EVENT_VIF_ADD, + FIB_EVENT_VIF_DEL, +}; + +struct fib_notifier_ops { + int family; + struct list_head list; + unsigned int (*fib_seq_read)(const struct net *net); + int (*fib_dump)(struct net *net, struct notifier_block *nb, + struct netlink_ext_ack *extack); + struct module *owner; + struct rcu_head rcu; +}; + +int call_fib_notifier(struct notifier_block *nb, + enum fib_event_type event_type, + struct fib_notifier_info *info); +int call_fib_notifiers(struct net *net, enum fib_event_type event_type, + struct fib_notifier_info *info); +int register_fib_notifier(struct net *net, struct notifier_block *nb, + void (*cb)(struct notifier_block *nb), + struct netlink_ext_ack *extack); +int unregister_fib_notifier(struct net *net, struct notifier_block *nb); +struct fib_notifier_ops * +fib_notifier_ops_register(const struct fib_notifier_ops *tmpl, struct net *net); +void fib_notifier_ops_unregister(struct fib_notifier_ops *ops); + +#endif -- cgit v1.3.1