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 --- fs/lockd/xdr.h | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) create mode 100644 fs/lockd/xdr.h (limited to 'fs/lockd/xdr.h') diff --git a/fs/lockd/xdr.h b/fs/lockd/xdr.h new file mode 100644 index 000000000..a1126cca9 --- /dev/null +++ b/fs/lockd/xdr.h @@ -0,0 +1,85 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * XDR types for the NLM protocol + * + * Copyright (C) 1996 Olaf Kirch + */ + +#ifndef _LOCKD_XDR_H +#define _LOCKD_XDR_H + +#include +#include +#include +#include + +#define SM_MAXSTRLEN 1024 +#define SM_PRIV_SIZE 16 + +struct nsm_private { + unsigned char data[SM_PRIV_SIZE]; +}; + +#define NLM_MAXCOOKIELEN 32 +#define NLM_MAXSTRLEN 1024 + +#define nlm_granted cpu_to_be32(NLM_LCK_GRANTED) +#define nlm_lck_denied cpu_to_be32(NLM_LCK_DENIED) +#define nlm_lck_denied_nolocks cpu_to_be32(NLM_LCK_DENIED_NOLOCKS) +#define nlm_lck_blocked cpu_to_be32(NLM_LCK_BLOCKED) +#define nlm_lck_denied_grace_period cpu_to_be32(NLM_LCK_DENIED_GRACE_PERIOD) + +/* Lock info passed via NLM */ +struct lockd_lock { + char * caller; + unsigned int len; /* length of "caller" */ + struct nfs_fh fh; + struct xdr_netobj oh; + u32 svid; + u64 lock_start; + u64 lock_len; + struct file_lock fl; +}; + +/* + * NLM cookies. Technically they can be 1K, but Linux only uses 8 bytes. + * FreeBSD uses 16, Apple Mac OS X 10.3 uses 20. Therefore we set it to + * 32 bytes. + */ + +struct lockd_cookie { + unsigned char data[NLM_MAXCOOKIELEN]; + unsigned int len; +}; + +/* + * Generic lockd arguments for all but sm_notify + */ +struct lockd_args { + struct lockd_cookie cookie; + struct lockd_lock lock; + u32 block; + u32 reclaim; + u32 state; +}; + +/* + * Generic lockd result + */ +struct lockd_res { + struct lockd_cookie cookie; + __be32 status; + struct lockd_lock lock; +}; + +/* + * statd callback when client has rebooted + */ +struct lockd_reboot { + char *mon; + unsigned int len; + u32 state; + struct nsm_private priv; +}; + +#endif /* _LOCKD_XDR_H */ -- cgit v1.3.1