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/rdma/ib.h | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 81 insertions(+) create mode 100644 include/rdma/ib.h (limited to 'include/rdma/ib.h') diff --git a/include/rdma/ib.h b/include/rdma/ib.h new file mode 100644 index 000000000..f7c185ff7 --- /dev/null +++ b/include/rdma/ib.h @@ -0,0 +1,81 @@ +/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */ +/* + * Copyright (c) 2010 Intel Corporation. All rights reserved. + */ + +#ifndef _RDMA_IB_H +#define _RDMA_IB_H + +#include +#include +#include +#include +#include + +struct ib_addr { + union { + __u8 uib_addr8[16]; + __be16 uib_addr16[8]; + __be32 uib_addr32[4]; + __be64 uib_addr64[2]; + } ib_u; +#define sib_addr8 ib_u.uib_addr8 +#define sib_addr16 ib_u.uib_addr16 +#define sib_addr32 ib_u.uib_addr32 +#define sib_addr64 ib_u.uib_addr64 +#define sib_raw ib_u.uib_addr8 +#define sib_subnet_prefix ib_u.uib_addr64[0] +#define sib_interface_id ib_u.uib_addr64[1] +}; + +static inline bool ib_addr_any(const struct ib_addr *a) +{ + return ((a->sib_addr64[0] | a->sib_addr64[1]) == 0); +} + +static inline bool ib_addr_loopback(const struct ib_addr *a) +{ + return ((a->sib_addr32[0] | a->sib_addr32[1] | + a->sib_addr32[2] | (a->sib_addr32[3] ^ htonl(1))) == 0); +} + +static inline void ib_addr_set(struct ib_addr *addr, + __be32 w1, __be32 w2, __be32 w3, __be32 w4) +{ + addr->sib_addr32[0] = w1; + addr->sib_addr32[1] = w2; + addr->sib_addr32[2] = w3; + addr->sib_addr32[3] = w4; +} + +static inline int ib_addr_cmp(const struct ib_addr *a1, const struct ib_addr *a2) +{ + return memcmp(a1, a2, sizeof(struct ib_addr)); +} + +struct sockaddr_ib { + unsigned short int sib_family; /* AF_IB */ + __be16 sib_pkey; + __be32 sib_flowinfo; + struct ib_addr sib_addr; + __be64 sib_sid; + __be64 sib_sid_mask; + __u64 sib_scope_id; +}; + +/* + * The IB interfaces that use write() as bi-directional ioctl() are + * fundamentally unsafe, since there are lots of ways to trigger "write()" + * calls from various contexts with elevated privileges. That includes the + * traditional suid executable error message writes, but also various kernel + * interfaces that can write to file descriptors. + * + * This function provides protection for the legacy API by restricting the + * calling context. + */ +static inline bool ib_safe_file_access(struct file *filp) +{ + return filp->f_cred == current_cred(); +} + +#endif /* _RDMA_IB_H */ -- cgit v1.3.1