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/lsm.h | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 security/lsm.h (limited to 'security/lsm.h') diff --git a/security/lsm.h b/security/lsm.h new file mode 100644 index 000000000..32f808ad4 --- /dev/null +++ b/security/lsm.h @@ -0,0 +1,50 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * LSM functions + */ + +#ifndef _LSM_H_ +#define _LSM_H_ + +#include +#include +#include + +/* LSM debugging */ +extern bool lsm_debug; +#define lsm_pr(...) pr_info(__VA_ARGS__) +#define lsm_pr_cont(...) pr_cont(__VA_ARGS__) +#define lsm_pr_dbg(...) \ + do { \ + if (lsm_debug) \ + pr_info(__VA_ARGS__); \ + } while (0) + +/* List of configured LSMs */ +extern unsigned int lsm_active_cnt; +extern const struct lsm_id *lsm_idlist[]; + +/* LSM blob configuration */ +extern struct lsm_blob_sizes blob_sizes; + +/* LSM blob caches */ +extern struct kmem_cache *lsm_file_cache; +extern struct kmem_cache *lsm_backing_file_cache; +extern struct kmem_cache *lsm_inode_cache; + +/* LSM blob allocators */ +int lsm_cred_alloc(struct cred *cred, gfp_t gfp); +int lsm_task_alloc(struct task_struct *task); + +/* LSM framework initializers */ + +#ifdef CONFIG_SECURITYFS +int securityfs_init(void); +#else +static inline int securityfs_init(void) +{ + return 0; +} +#endif /* CONFIG_SECURITYFS */ + +#endif /* _LSM_H_ */ -- cgit v1.3.1