From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- 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