1 files changed, 60 insertions, 23 deletions

diff --git a/rust/kernel/security.rs b/rust/kernel/security.rs
index 2522868862a1..9d271695265f 100644
--- a/rust/kernel/security.rs
+++ b/rust/kernel/security.rs
@@ -8,67 +8,104 @@
 
 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 `secdata` and `seclen` fields correspond to a valid security context as returned by a
-/// successful call to `security_secid_to_secctx`, that has not yet been destroyed by calling
-/// `security_release_secctx`.
+/// 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 {
-    secdata: *mut core::ffi::c_char,
-    seclen: usize,
+    ctx: bindings::lsm_context,
 }
 
 impl SecurityCtx {
     /// Get the security context given its id.
+    #[inline]
     pub fn from_secid(secid: u32) -> Result<Self> {
-        let mut secdata = core::ptr::null_mut();
-        let mut seclen = 0u32;
-        // SAFETY: Just a C FFI call. The pointers are valid for writes.
-        to_result(unsafe { bindings::security_secid_to_secctx(secid, &mut secdata, &mut seclen) })?;
+        // 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 {
-            secdata,
-            seclen: seclen as usize,
-        })
+        Ok(Self { ctx })
     }
 
     /// Returns whether the security context is empty.
+    #[inline]
     pub fn is_empty(&self) -> bool {
-        self.seclen == 0
+        self.ctx.len == 0
     }
 
     /// Returns the length of this security context.
+    #[inline]
     pub fn len(&self) -> usize {
-        self.seclen
+        self.ctx.len as usize
     }
 
     /// Returns the bytes for this security context.
+    #[inline]
     pub fn as_bytes(&self) -> &[u8] {
-        let ptr = self.secdata;
+        let ptr = self.ctx.context;
         if ptr.is_null() {
-            debug_assert_eq!(self.seclen, 0);
+            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
-        // `seclen` bytes. Furthermore, if the length is zero, then we have ensured that the
+        // `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.seclen) }
+        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 frees a pointer that came from a successful
-        // call to `security_secid_to_secctx` and has not yet been destroyed by
-        // `security_release_secctx`.
-        unsafe { bindings::security_release_secctx(self.secdata, self.seclen as u32) };
+        // 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) };
     }
 }