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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2024 Google LLC.
//! Linux Security Modules (LSM).//!//! C header: [`include/linux/security.h`](srctree/include/linux/security.h).
use crate::{ bindings, cred::Credential, error::{to_result, Result}, fs::File,};
/// Calls the security modules to determine if the given task can become the manager of a binder/// context.#[inline]pub fn binder_set_context_mgr(mgr: &Credential) -> Result { // SAFETY: `mrg.0` is valid because the shared reference guarantees a nonzero refcount. to_result(unsafe { bindings::security_binder_set_context_mgr(mgr.as_ptr()) })}
/// Calls the security modules to determine if binder transactions are allowed from task `from` to/// task `to`.#[inline]pub fn binder_transaction(from: &Credential, to: &Credential) -> Result { // SAFETY: `from` and `to` are valid because the shared references guarantee nonzero refcounts. to_result(unsafe { bindings::security_binder_transaction(from.as_ptr(), to.as_ptr()) })}
/// Calls the security modules to determine if task `from` is allowed to send binder objects/// (owned by itself or other processes) to task `to` through a binder transaction.#[inline]pub fn binder_transfer_binder(from: &Credential, to: &Credential) -> Result { // SAFETY: `from` and `to` are valid because the shared references guarantee nonzero refcounts. to_result(unsafe { bindings::security_binder_transfer_binder(from.as_ptr(), to.as_ptr()) })}
/// Calls the security modules to determine if task `from` is allowed to send the given file to/// task `to` (which would get its own file descriptor) through a binder transaction.#[inline]pub fn binder_transfer_file(from: &Credential, to: &Credential, file: &File) -> Result { // SAFETY: `from`, `to` and `file` are valid because the shared references guarantee nonzero // refcounts. to_result(unsafe { bindings::security_binder_transfer_file(from.as_ptr(), to.as_ptr(), file.as_ptr()) })}
/// A security context string.////// # Invariants////// The `ctx` field corresponds to a valid security context as returned by a successful call to/// `security_secid_to_secctx`, that has not yet been released by `security_release_secctx`.pub struct SecurityCtx { ctx: bindings::lsm_context,}
impl SecurityCtx { /// Get the security context given its id. #[inline] pub fn from_secid(secid: u32) -> Result<Self> { // SAFETY: `struct lsm_context` can be initialized to all zeros. let mut ctx: bindings::lsm_context = unsafe { core::mem::zeroed() };
// SAFETY: Just a C FFI call. The pointer is valid for writes. to_result(unsafe { bindings::security_secid_to_secctx(secid, &mut ctx) })?;
// INVARIANT: If the above call did not fail, then we have a valid security context. Ok(Self { ctx }) }
/// Returns whether the security context is empty. #[inline] pub fn is_empty(&self) -> bool { self.ctx.len == 0 }
/// Returns the length of this security context. #[inline] pub fn len(&self) -> usize { self.ctx.len as usize }
/// Returns the bytes for this security context. #[inline] pub fn as_bytes(&self) -> &[u8] { let ptr = self.ctx.context; if ptr.is_null() { debug_assert_eq!(self.len(), 0); // We can't pass a null pointer to `slice::from_raw_parts` even if the length is zero. return &[]; }
// SAFETY: The call to `security_secid_to_secctx` guarantees that the pointer is valid for // `self.len()` bytes. Furthermore, if the length is zero, then we have ensured that the // pointer is not null. unsafe { core::slice::from_raw_parts(ptr.cast(), self.len()) } }}
impl Drop for SecurityCtx { #[inline] fn drop(&mut self) { // SAFETY: By the invariant of `Self`, this releases an lsm context that came from a // successful call to `security_secid_to_secctx` and has not yet been released. unsafe { bindings::security_release_secctx(&mut self.ctx) }; }}