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 --- rust/bindings/lib.rs | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) create mode 100644 rust/bindings/lib.rs (limited to 'rust/bindings/lib.rs') diff --git a/rust/bindings/lib.rs b/rust/bindings/lib.rs new file mode 100644 index 000000000..812f8e5a0 --- /dev/null +++ b/rust/bindings/lib.rs @@ -0,0 +1,83 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Bindings. +//! +//! Imports the generated bindings by `bindgen`. +//! +//! This crate may not be directly used. If you need a kernel C API that is +//! not ported or wrapped in the `kernel` crate, then do so first instead of +//! using this crate. + +#![no_std] +#![allow( + clippy::all, + missing_docs, + non_camel_case_types, + non_upper_case_globals, + non_snake_case, + improper_ctypes, + unreachable_pub, + unsafe_op_in_unsafe_fn +)] +#![feature(cfi_encoding)] + +#[allow(dead_code)] +#[allow(clippy::cast_lossless)] +#[allow(clippy::ptr_as_ptr)] +#[allow(clippy::ref_as_ptr)] +#[allow(clippy::undocumented_unsafe_blocks)] +#[cfg_attr(CONFIG_RUSTC_HAS_UNNECESSARY_TRANSMUTES, allow(unnecessary_transmutes))] +#[cfg_attr( + CONFIG_RUSTC_HAS_SUSPICIOUS_RUNTIME_SYMBOL_DEFINITIONS, + allow(suspicious_runtime_symbol_definitions) +)] +mod bindings_raw { + use pin_init::{MaybeZeroable, Zeroable}; + + // Manual definition for blocklisted types. + type __kernel_size_t = usize; + type __kernel_ssize_t = isize; + type __kernel_ptrdiff_t = isize; + + // `bindgen` doesn't automatically do this, see + // + // + // SAFETY: `__BindgenBitfieldUnit` is a newtype around `Storage`. + unsafe impl Zeroable for __BindgenBitfieldUnit where Storage: Zeroable {} + + // Use glob import here to expose all helpers. + // Symbols defined within the module will take precedence to the glob import. + pub use super::bindings_helper::*; + include!(concat!( + env!("OBJTREE"), + "/rust/bindings/bindings_generated.rs" + )); +} + +// When both a directly exposed symbol and a helper exists for the same function, +// the directly exposed symbol is preferred and the helper becomes dead code, so +// ignore the warning here. +#[allow(dead_code)] +mod bindings_helper { + // Import the generated bindings for types. + use super::bindings_raw::*; + include!(concat!( + env!("OBJTREE"), + "/rust/bindings/bindings_helpers_generated.rs" + )); +} + +pub use bindings_raw::*; + +pub const compat_ptr_ioctl: Option< + unsafe extern "C" fn(*mut file, ffi::c_uint, ffi::c_ulong) -> ffi::c_long, +> = { + #[cfg(CONFIG_COMPAT)] + { + Some(bindings_raw::compat_ptr_ioctl) + } + #[cfg(not(CONFIG_COMPAT))] + { + None + } +}; -- cgit v1.3.1