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 --- security/keys/sysctl.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 security/keys/sysctl.c (limited to 'security/keys/sysctl.c') diff --git a/security/keys/sysctl.c b/security/keys/sysctl.c new file mode 100644 index 000000000..cde08c478 --- /dev/null +++ b/security/keys/sysctl.c @@ -0,0 +1,76 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Key management controls + * + * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include +#include +#include "internal.h" + +static const struct ctl_table key_sysctls[] = { + { + .procname = "maxkeys", + .data = &key_quota_maxkeys, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) SYSCTL_ONE, + .extra2 = (void *) SYSCTL_INT_MAX, + }, + { + .procname = "maxbytes", + .data = &key_quota_maxbytes, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) SYSCTL_ONE, + .extra2 = (void *) SYSCTL_INT_MAX, + }, + { + .procname = "root_maxkeys", + .data = &key_quota_root_maxkeys, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) SYSCTL_ONE, + .extra2 = (void *) SYSCTL_INT_MAX, + }, + { + .procname = "root_maxbytes", + .data = &key_quota_root_maxbytes, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) SYSCTL_ONE, + .extra2 = (void *) SYSCTL_INT_MAX, + }, + { + .procname = "gc_delay", + .data = &key_gc_delay, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) SYSCTL_ZERO, + .extra2 = (void *) SYSCTL_INT_MAX, + }, +#ifdef CONFIG_PERSISTENT_KEYRINGS + { + .procname = "persistent_keyring_expiry", + .data = &persistent_keyring_expiry, + .maxlen = sizeof(unsigned), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = (void *) SYSCTL_ZERO, + .extra2 = (void *) SYSCTL_INT_MAX, + }, +#endif +}; + +static int __init init_security_keys_sysctls(void) +{ + register_sysctl_init("kernel/keys", key_sysctls); + return 0; +} +early_initcall(init_security_keys_sysctls); -- cgit v1.3.1