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/nfsd/idmap.h | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) create mode 100644 fs/nfsd/idmap.h (limited to 'fs/nfsd/idmap.h') diff --git a/fs/nfsd/idmap.h b/fs/nfsd/idmap.h new file mode 100644 index 000000000..23cc85d1e --- /dev/null +++ b/fs/nfsd/idmap.h @@ -0,0 +1,60 @@ +/* + * Mapping of UID to name and vice versa. + * + * Copyright (c) 2002, 2003 The Regents of the University of + * Michigan. All rights reserved. +> * + * Marius Aamodt Eriksen + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the University nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR + * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef LINUX_NFSD_IDMAP_H +#define LINUX_NFSD_IDMAP_H + +#include +#include +#include + +#ifdef CONFIG_NFSD_V4 +int nfsd_idmap_init(struct net *); +void nfsd_idmap_shutdown(struct net *); +#else +static inline int nfsd_idmap_init(struct net *net) +{ + return 0; +} +static inline void nfsd_idmap_shutdown(struct net *net) +{ +} +#endif + +__be32 nfsd_map_name_to_uid(struct svc_rqst *, const char *, size_t, kuid_t *); +__be32 nfsd_map_name_to_gid(struct svc_rqst *, const char *, size_t, kgid_t *); +__be32 nfsd4_encode_user(struct xdr_stream *, struct svc_rqst *, kuid_t); +__be32 nfsd4_encode_group(struct xdr_stream *, struct svc_rqst *, kgid_t); + +#endif /* LINUX_NFSD_IDMAP_H */ -- cgit v1.3.1