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[37.33.180.149]) by smtp.gmail.com with ESMTPSA id 38308e7fff4ca-382eb91dfbdsm5256091fa.44.2026.01.06.08.13.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Jan 2026 08:13:10 -0800 (PST) From: Kari Argillander Date: Tue, 06 Jan 2026 18:11:41 +0200 Subject: [PATCH RFC v2 03/11] rust: miscdevice: fix use after free because missing .owner Precedence: bulk X-Mailing-List: linux-modules@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260106-this_module_fix-v2-3-842ac026f00b@gmail.com> References: <20260106-this_module_fix-v2-0-842ac026f00b@gmail.com> In-Reply-To: <20260106-this_module_fix-v2-0-842ac026f00b@gmail.com> To: Miguel Ojeda , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Alexandre Courbot Cc: Greg Kroah-Hartman , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-modules@vger.kernel.org, Luis Chamberlain , Petr Pavlu , Daniel Gomez , Sami Tolvanen , Aaron Tomlin , Kari Argillander , Youseok Yang X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1767715983; l=2370; i=kari.argillander@gmail.com; s=20251219; h=from:subject:message-id; bh=891dg5NeMMgINCtxfUx5z2GhTLzUtO+bREujFmK9Vxo=; b=XTB+sVOL63dP4+VWC+iJBYkzCmbAeMtvvB++kKg5rg1gpSNNQmkqwSCagBJoh3NsSq0qwA4nQ VI5WDjBJtTIDa6b1hFQyngjY104t7ooXovgREEee0nWRpTUeFWWqvFb X-Developer-Key: i=kari.argillander@gmail.com; a=ed25519; pk=RwSxyhTpE3z4sywdDbIkC3q33ZQLNyhYWxT44iTY6r4= Currently if miscdevice driver is compiled as module it can cause use after free when unloading. To reproduce problem with Rust sample driver we can do: tail -f /dev/rust-misc-device # And same time as device is open sudo rmmod rust_misc_device_module This will crash system. Fix is to have .owner field filled with module information. We pass this owner information through vtable. Reported-by: Youseok Yang Closes: https://github.com/Rust-for-Linux/linux/issues/1182 Fixes: f893691e7426 ("rust: miscdevice: add base miscdevice abstraction") Signed-off-by: Kari Argillander --- rust/kernel/miscdevice.rs | 5 +++++ samples/rust/rust_misc_device.rs | 1 + 2 files changed, 6 insertions(+) diff --git a/rust/kernel/miscdevice.rs b/rust/kernel/miscdevice.rs index ba64c8a858f0..d4b0c35c4b60 100644 --- a/rust/kernel/miscdevice.rs +++ b/rust/kernel/miscdevice.rs @@ -18,6 +18,7 @@ mm::virt::VmaNew, prelude::*, seq_file::SeqFile, + this_module::ThisModule, types::{ForeignOwnable, Opaque}, }; use core::{marker::PhantomData, pin::Pin}; @@ -112,6 +113,9 @@ fn drop(self: Pin<&mut Self>) { /// Trait implemented by the private data of an open misc device. #[vtable] pub trait MiscDevice: Sized { + /// Module ownership for this device, provided via `THIS_MODULE`. + type ThisModule: ThisModule; + /// What kind of pointer should `Self` be wrapped in. type Ptr: ForeignOwnable + Send + Sync; @@ -388,6 +392,7 @@ impl MiscdeviceVTable { } const VTABLE: bindings::file_operations = bindings::file_operations { + owner: T::ThisModule::OWNER.as_ptr(), open: Some(Self::open), release: Some(Self::release), mmap: if T::HAS_MMAP { Some(Self::mmap) } else { None }, diff --git a/samples/rust/rust_misc_device.rs b/samples/rust/rust_misc_device.rs index 49dd5814e1ab..464e3026e6e3 100644 --- a/samples/rust/rust_misc_device.rs +++ b/samples/rust/rust_misc_device.rs @@ -155,6 +155,7 @@ struct RustMiscDevice { #[vtable] impl MiscDevice for RustMiscDevice { + type ThisModule = THIS_MODULE; type Ptr = Pin>; fn open(_file: &File, misc: &MiscDeviceRegistration) -> Result>> { -- 2.43.0