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2024-04-16rust: macros: fix soundness issue in `module!` macroBenno Lossin1-75/+115
The `module!` macro creates glue code that are called by C to initialize the Rust modules using the `Module::init` function. Part of this glue code are the local functions `__init` and `__exit` that are used to initialize/destroy the Rust module. These functions are safe and also visible to the Rust mod in which the `module!` macro is invoked. This means that they can be called by other safe Rust code. But since they contain `unsafe` blocks that rely on only being called at the right time, this is a soundness issue. Wrap these generated functions inside of two private modules, this guarantees that the public functions cannot be called from the outside. Make the safe functions `unsafe` and add SAFETY comments. Cc: stable@vger.kernel.org Reported-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Closes: https://github.com/Rust-for-Linux/linux/issues/629 Fixes: 1fbde52bde73 ("rust: add `macros` crate") Signed-off-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Wedson Almeida Filho <walmeida@microsoft.com> Link: https://lore.kernel.org/r/20240401185222.12015-1-benno.lossin@proton.me [ Moved `THIS_MODULE` out of the private-in-private modules since it should remain public, as Dirk Behme noticed [1]. Capitalized comments, avoided newline in non-list SAFETY comments and reworded to add Reported-by and newline. ] Link: https://rust-for-linux.zulipchat.com/#narrow/stream/291565-Help/topic/x/near/433512583 [1] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-02-25rust: module: place generated init_module() function in .init.textThomas Bertschinger1-1/+6
Currently Rust kernel modules have their init code placed in the `.text` section of the .ko file. I don't think this causes any real problems for Rust modules as long as all code called during initialization lives in `.text`. However, if a Rust `init_module()` function (that lives in `.text`) calls a function marked with `__init` (in C) or `#[link_section = ".init.text"]` (in Rust), then a warning is generated by modpost because that function lives in `.init.text`. For example: WARNING: modpost: fs/bcachefs/bcachefs: section mismatch in reference: init_module+0x6 (section: .text) -> _RNvXCsj7d3tFpT5JS_15bcachefs_moduleNtB2_8BcachefsNtCsjDtqRIL3JAG_6kernel6Module4init (section: .init.text) I ran into this while experimenting with converting the bcachefs kernel module from C to Rust. The module's `init()`, written in Rust, calls C functions like `bch2_vfs_init()` which are placed in `.init.text`. This patch places the macro-generated `init_module()` Rust function in the `.init.text` section. It also marks `init_module()` as unsafe--now it may not be called after module initialization completes because it may be freed already. Note that this is not enough on its own to actually get all the module initialization code in that section. The module author must still add the `#[link_section = ".init.text"]` attribute to the Rust `init()` in the `impl kernel::Module` block in order to then call `__init` functions. However, this patch enables module authors do so, when previously it would not be possible (without warnings). Signed-off-by: Thomas Bertschinger <tahbertschinger@gmail.com> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240206153806.567055-1-tahbertschinger@gmail.com [ Reworded title to add prefix. ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-08-10btf, scripts: rust: drop is_rust_module.shAndrea Righi1-1/+1
With commit c1177979af9c ("btf, scripts: Exclude Rust CUs with pahole") we are now able to use pahole directly to identify Rust compilation units (CUs) and exclude them from generating BTF debugging information (when DEBUG_INFO_BTF is enabled). And if pahole doesn't support the --lang-exclude flag, we can't enable both RUST and DEBUG_INFO_BTF at the same time. So, in any case, the script is_rust_module.sh is just redundant and we can drop it. NOTE: we may also be able to drop the "Rust loadable module" mark inside Rust modules, but it seems safer to keep it for now to make sure we are not breaking any external tool that may potentially rely on it. Signed-off-by: Andrea Righi <andrea.righi@canonical.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Eric Curtin <ecurtin@redhat.com> Reviewed-by: Eric Curtin <ecurtin@redhat.com> Reviewed-by: Neal Gompa <neal@gompa.dev> Reviewed-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Acked-by: Daniel Xu <dxu@dxuuu.xyz> Link: https://lore.kernel.org/r/20230704052136.155445-1-andrea.righi@canonical.com [ Picked the `Reviewed-by`s from the old patch too. ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-12rust: error: Rename to_kernel_errno() -> to_errno()Asahi Lina1-1/+1
This is kernel code, so specifying "kernel" is redundant. Let's simplify things and just call it to_errno(). Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Asahi Lina <lina@asahilina.net> Link: https://lore.kernel.org/r/20230224-rust-error-v3-1-03779bddc02b@asahilina.net Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-11rust: macros: Allow specifying multiple module aliasesAsahi Lina1-5/+25
Modules can (and usually do) have multiple alias tags, in order to specify multiple possible device matches for autoloading. Allow this by changing the alias ModuleInfo field to an Option<Vec<String>>. Note: For normal device IDs this is autogenerated by modpost (which is not properly integrated with Rust support yet), so it is useful to be able to manually add device match aliases for now, and should still be useful in the future for corner cases that modpost does not handle. This pulls in the expect_group() helper from the rfl/rust branch (with credit to authors). Co-developed-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Co-developed-by: Finn Behrens <me@kloenk.dev> Signed-off-by: Finn Behrens <me@kloenk.dev> Co-developed-by: Sumera Priyadarsini <sylphrenadin@gmail.com> Signed-off-by: Sumera Priyadarsini <sylphrenadin@gmail.com> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Signed-off-by: Asahi Lina <lina@asahilina.net> Link: https://lore.kernel.org/r/20230224-rust-macros-v2-1-7396e8b7018d@asahilina.net Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2022-12-04rust: macros: take string literals in `module!`Gary Guo1-5/+5
Instead of taking binary string literals, take string ones instead, making it easier for users to define a module, i.e. instead of calling `module!` like: module! { ... name: b"rust_minimal", ... } now it is called as: module! { ... name: "rust_minimal", ... } Module names, aliases and license strings are restricted to ASCII only. However, the author and the description allows UTF-8. For simplicity (avoid parsing), escape sequences and raw string literals are not yet handled. Link: https://github.com/Rust-for-Linux/linux/issues/252 Link: https://lore.kernel.org/lkml/YukvvPOOu8uZl7+n@yadro.com/ Signed-off-by: Gary Guo <gary@garyguo.net> [Reworded, adapted for upstream and applied latest changes] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2022-09-28rust: add `macros` crateMiguel Ojeda1-0/+282
This crate contains all the procedural macros ("proc macros") shared by all the kernel. Procedural macros allow to create syntax extensions. They run at compile-time and can consume as well as produce Rust syntax. For instance, the `module!` macro that is used by Rust modules is implemented here. It allows to easily declare the equivalent information to the `MODULE_*` macros in C modules, e.g.: module! { type: RustMinimal, name: b"rust_minimal", author: b"Rust for Linux Contributors", description: b"Rust minimal sample", license: b"GPL", } Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Sumera Priyadarsini <sylphrenadin@gmail.com> Signed-off-by: Sumera Priyadarsini <sylphrenadin@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Matthew Bakhtiari <dev@mtbk.me> Signed-off-by: Matthew Bakhtiari <dev@mtbk.me> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>