3 use ptr::{self, NonNull};
7 use ops::{Deref, DerefMut, Index, IndexMut, CoerceUnsized};
10 use fortanix_sgx_abi::*;
11 use super::super::mem::is_user_range;
13 /// A type that can be safely read from or written to userspace.
15 /// Non-exhaustive list of specific requirements for reading and writing:
16 /// * **Type is `Copy`** (and therefore also not `Drop`). Copies will be
17 /// created when copying from/to userspace. Destructors will not be called.
18 /// * **No references or Rust-style owned pointers** (`Vec`, `Arc`, etc.). When
19 /// reading from userspace, references into enclave memory must not be
20 /// created. Also, only enclave memory is considered managed by the Rust
21 /// compiler's static analysis. When reading from userspace, there can be no
22 /// guarantee that the value correctly adheres to the expectations of the
23 /// type. When writing to userspace, memory addresses of data in enclave
24 /// memory must not be leaked for confidentiality reasons. `User` and
25 /// `UserRef` are also not allowed for the same reasons.
26 /// * **No fat pointers.** When reading from userspace, the size or vtable
27 /// pointer could be automatically interpreted and used by the code. When
28 /// writing to userspace, memory addresses of data in enclave memory (such
29 /// as vtable pointers) must not be leaked for confidentiality reasons.
31 /// Non-exhaustive list of specific requirements for reading from userspace:
32 /// * **Any bit pattern is valid** for this type (no `enum`s). There can be no
33 /// guarantee that the value correctly adheres to the expectations of the
34 /// type, so any value must be valid for this type.
36 /// Non-exhaustive list of specific requirements for writing to userspace:
37 /// * **No pointers to enclave memory.** Memory addresses of data in enclave
38 /// memory must not be leaked for confidentiality reasons.
39 /// * **No internal padding.** Padding might contain previously-initialized
40 /// secret data stored at that memory location and must not be leaked for
41 /// confidentiality reasons.
42 #[unstable(feature = "sgx_platform", issue = "56975")]
43 pub unsafe trait UserSafeSized: Copy + Sized {}
45 #[unstable(feature = "sgx_platform", issue = "56975")]
46 unsafe impl UserSafeSized for u8 {}
47 #[unstable(feature = "sgx_platform", issue = "56975")]
48 unsafe impl<T> UserSafeSized for FifoDescriptor<T> {}
49 #[unstable(feature = "sgx_platform", issue = "56975")]
50 unsafe impl UserSafeSized for ByteBuffer {}
51 #[unstable(feature = "sgx_platform", issue = "56975")]
52 unsafe impl UserSafeSized for Usercall {}
53 #[unstable(feature = "sgx_platform", issue = "56975")]
54 unsafe impl UserSafeSized for Return {}
55 #[unstable(feature = "sgx_platform", issue = "56975")]
56 unsafe impl<T: UserSafeSized> UserSafeSized for [T; 2] {}
58 /// A type that can be represented in memory as one or more `UserSafeSized`s.
59 #[unstable(feature = "sgx_platform", issue = "56975")]
60 pub unsafe trait UserSafe {
61 /// Equivalent to `mem::align_of::<Self>`.
62 fn align_of() -> usize;
64 /// Construct a pointer to `Self` given a memory range in user space.
66 /// N.B., this takes a size, not a length!
70 /// The caller must ensure the memory range is in user memory, is the
71 /// correct size and is correctly aligned and points to the right type.
72 unsafe fn from_raw_sized_unchecked(ptr: *mut u8, size: usize) -> *mut Self;
74 /// Construct a pointer to `Self` given a memory range.
76 /// N.B., this takes a size, not a length!
80 /// The caller must ensure the memory range points to the correct type.
84 /// This function panics if:
86 /// * the pointer is not aligned.
87 /// * the pointer is null.
88 /// * the pointed-to range is not in user memory.
89 unsafe fn from_raw_sized(ptr: *mut u8, size: usize) -> NonNull<Self> {
90 let ret = Self::from_raw_sized_unchecked(ptr, size);
92 NonNull::new_unchecked(ret as _)
95 /// Checks if a pointer may point to `Self` in user memory.
99 /// The caller must ensure the memory range points to the correct type and
100 /// length (if this is a slice).
104 /// This function panics if:
106 /// * the pointer is not aligned.
107 /// * the pointer is null.
108 /// * the pointed-to range is not in user memory.
109 unsafe fn check_ptr(ptr: *const Self) {
110 let is_aligned = |p| -> bool {
111 0 == (p as usize) & (Self::align_of() - 1)
114 assert!(is_aligned(ptr as *const u8));
115 assert!(is_user_range(ptr as _, mem::size_of_val(&*ptr)));
116 assert!(!ptr.is_null());
120 #[unstable(feature = "sgx_platform", issue = "56975")]
121 unsafe impl<T: UserSafeSized> UserSafe for T {
122 fn align_of() -> usize {
126 unsafe fn from_raw_sized_unchecked(ptr: *mut u8, size: usize) -> *mut Self {
127 assert_eq!(size, mem::size_of::<T>());
132 #[unstable(feature = "sgx_platform", issue = "56975")]
133 unsafe impl<T: UserSafeSized> UserSafe for [T] {
134 fn align_of() -> usize {
138 unsafe fn from_raw_sized_unchecked(ptr: *mut u8, size: usize) -> *mut Self {
139 let elem_size = mem::size_of::<T>();
140 assert_eq!(size % elem_size, 0);
141 let len = size / elem_size;
142 slice::from_raw_parts_mut(ptr as _, len)
146 /// A reference to some type in userspace memory. `&UserRef<T>` is equivalent
147 /// to `&T` in enclave memory. Access to the memory is only allowed by copying
148 /// to avoid TOCTTOU issues. After copying, code should make sure to completely
149 /// check the value before use.
151 /// It is also possible to obtain a mutable reference `&mut UserRef<T>`. Unlike
152 /// regular mutable references, these are not exclusive. Userspace may always
153 /// write to the backing memory at any time, so it can't be assumed that there
154 /// the pointed-to memory is uniquely borrowed. The two different refence types
155 /// are used solely to indicate intent: a mutable reference is for writing to
156 /// user memory, an immutable reference for reading from user memory.
157 #[unstable(feature = "sgx_platform", issue = "56975")]
158 pub struct UserRef<T: ?Sized>(UnsafeCell<T>);
159 /// An owned type in userspace memory. `User<T>` is equivalent to `Box<T>` in
160 /// enclave memory. Access to the memory is only allowed by copying to avoid
161 /// TOCTTOU issues. The user memory will be freed when the value is dropped.
162 /// After copying, code should make sure to completely check the value before
164 #[unstable(feature = "sgx_platform", issue = "56975")]
165 pub struct User<T: UserSafe + ?Sized>(NonNull<UserRef<T>>);
167 trait NewUserRef<T: ?Sized> {
168 unsafe fn new_userref(v: T) -> Self;
171 impl<T: ?Sized> NewUserRef<*mut T> for NonNull<UserRef<T>> {
172 unsafe fn new_userref(v: *mut T) -> Self {
173 NonNull::new_unchecked(v as _)
177 impl<T: ?Sized> NewUserRef<NonNull<T>> for NonNull<UserRef<T>> {
178 unsafe fn new_userref(v: NonNull<T>) -> Self {
179 NonNull::new_userref(v.as_ptr())
183 #[unstable(feature = "sgx_platform", issue = "56975")]
184 impl<T: ?Sized> User<T> where T: UserSafe {
185 // This function returns memory that is practically uninitialized, but is
186 // not considered "unspecified" or "undefined" for purposes of an
187 // optimizing compiler. This is achieved by returning a pointer from
188 // from outside as obtained by `super::alloc`.
189 fn new_uninit_bytes(size: usize) -> Self {
191 let ptr = super::alloc(size, T::align_of()).expect("User memory allocation failed");
192 User(NonNull::new_userref(T::from_raw_sized(ptr as _, size)))
196 /// Copies `val` into freshly allocated space in user memory.
197 pub fn new_from_enclave(val: &T) -> Self {
199 let ret = Self::new_uninit_bytes(mem::size_of_val(val));
201 val as *const T as *const u8,
202 ret.0.as_ptr() as *mut u8,
203 mem::size_of_val(val)
209 /// Creates an owned `User<T>` from a raw pointer.
212 /// The caller must ensure `ptr` points to `T`, is freeable with the `free`
213 /// usercall and the alignment of `T`, and is uniquely owned.
216 /// This function panics if:
218 /// * The pointer is not aligned
219 /// * The pointer is null
220 /// * The pointed-to range is not in user memory
221 pub unsafe fn from_raw(ptr: *mut T) -> Self {
223 User(NonNull::new_userref(ptr))
226 /// Converts this value into a raw pointer. The value will no longer be
227 /// automatically freed.
228 pub fn into_raw(self) -> *mut T {
235 #[unstable(feature = "sgx_platform", issue = "56975")]
236 impl<T> User<T> where T: UserSafe {
237 /// Allocate space for `T` in user memory.
238 pub fn uninitialized() -> Self {
239 Self::new_uninit_bytes(mem::size_of::<T>())
243 #[unstable(feature = "sgx_platform", issue = "56975")]
244 impl<T> User<[T]> where [T]: UserSafe {
245 /// Allocate space for a `[T]` of `n` elements in user memory.
246 pub fn uninitialized(n: usize) -> Self {
247 Self::new_uninit_bytes(n * mem::size_of::<T>())
250 /// Creates an owned `User<[T]>` from a raw thin pointer and a slice length.
253 /// The caller must ensure `ptr` points to `len` elements of `T`, is
254 /// freeable with the `free` usercall and the alignment of `T`, and is
258 /// This function panics if:
260 /// * The pointer is not aligned
261 /// * The pointer is null
262 /// * The pointed-to range is not in user memory
263 pub unsafe fn from_raw_parts(ptr: *mut T, len: usize) -> Self {
264 User(NonNull::new_userref(<[T]>::from_raw_sized(ptr as _, len * mem::size_of::<T>())))
268 #[unstable(feature = "sgx_platform", issue = "56975")]
269 impl<T: ?Sized> UserRef<T> where T: UserSafe {
270 /// Creates a `&UserRef<[T]>` from a raw pointer.
273 /// The caller must ensure `ptr` points to `T`.
276 /// This function panics if:
278 /// * The pointer is not aligned
279 /// * The pointer is null
280 /// * The pointed-to range is not in user memory
281 pub unsafe fn from_ptr<'a>(ptr: *const T) -> &'a Self {
283 &*(ptr as *const Self)
286 /// Creates a `&mut UserRef<[T]>` from a raw pointer. See the struct
287 /// documentation for the nuances regarding a `&mut UserRef<T>`.
290 /// The caller must ensure `ptr` points to `T`.
293 /// This function panics if:
295 /// * The pointer is not aligned
296 /// * The pointer is null
297 /// * The pointed-to range is not in user memory
298 pub unsafe fn from_mut_ptr<'a>(ptr: *mut T) -> &'a mut Self {
300 &mut*(ptr as *mut Self)
303 /// Copies `val` into user memory.
306 /// This function panics if the destination doesn't have the same size as
307 /// the source. This can happen for dynamically-sized types such as slices.
308 pub fn copy_from_enclave(&mut self, val: &T) {
310 assert_eq!(mem::size_of_val(val), mem::size_of_val( &*self.0.get() ));
312 val as *const T as *const u8,
313 self.0.get() as *mut T as *mut u8,
314 mem::size_of_val(val)
319 /// Copies the value from user memory and place it into `dest`.
322 /// This function panics if the destination doesn't have the same size as
323 /// the source. This can happen for dynamically-sized types such as slices.
324 pub fn copy_to_enclave(&self, dest: &mut T) {
326 assert_eq!(mem::size_of_val(dest), mem::size_of_val( &*self.0.get() ));
328 self.0.get() as *const T as *const u8,
329 dest as *mut T as *mut u8,
330 mem::size_of_val(dest)
335 /// Obtain a raw pointer from this reference.
336 pub fn as_raw_ptr(&self) -> *const T {
337 self as *const _ as _
340 /// Obtain a raw pointer from this reference.
341 pub fn as_raw_mut_ptr(&mut self) -> *mut T {
346 #[unstable(feature = "sgx_platform", issue = "56975")]
347 impl<T> UserRef<T> where T: UserSafe {
348 /// Copies the value from user memory into enclave memory.
349 pub fn to_enclave(&self) -> T {
350 unsafe { ptr::read(self.0.get()) }
354 #[unstable(feature = "sgx_platform", issue = "56975")]
355 impl<T> UserRef<[T]> where [T]: UserSafe {
356 /// Creates a `&UserRef<[T]>` from a raw thin pointer and a slice length.
359 /// The caller must ensure `ptr` points to `n` elements of `T`.
362 /// This function panics if:
364 /// * The pointer is not aligned
365 /// * The pointer is null
366 /// * The pointed-to range is not in user memory
367 pub unsafe fn from_raw_parts<'a>(ptr: *const T, len: usize) -> &'a Self {
368 &*(<[T]>::from_raw_sized(ptr as _, len * mem::size_of::<T>()).as_ptr() as *const Self)
371 /// Creates a `&mut UserRef<[T]>` from a raw thin pointer and a slice length.
372 /// See the struct documentation for the nuances regarding a
373 /// `&mut UserRef<T>`.
376 /// The caller must ensure `ptr` points to `n` elements of `T`.
379 /// This function panics if:
381 /// * The pointer is not aligned
382 /// * The pointer is null
383 /// * The pointed-to range is not in user memory
384 pub unsafe fn from_raw_parts_mut<'a>(ptr: *mut T, len: usize) -> &'a mut Self {
385 &mut*(<[T]>::from_raw_sized(ptr as _, len * mem::size_of::<T>()).as_ptr() as *mut Self)
388 /// Obtain a raw pointer to the first element of this user slice.
389 pub fn as_ptr(&self) -> *const T {
393 /// Obtain a raw pointer to the first element of this user slice.
394 pub fn as_mut_ptr(&mut self) -> *mut T {
398 /// Obtain the number of elements in this user slice.
399 pub fn len(&self) -> usize {
400 unsafe { (*self.0.get()).len() }
403 /// Copies the value from user memory and place it into `dest`. Afterwards,
404 /// `dest` will contain exactly `self.len()` elements.
407 /// This function panics if the destination doesn't have the same size as
408 /// the source. This can happen for dynamically-sized types such as slices.
409 pub fn copy_to_enclave_vec(&self, dest: &mut Vec<T>) {
411 if let Some(missing) = self.len().checked_sub(dest.capacity()) {
412 dest.reserve(missing)
414 dest.set_len(self.len());
415 self.copy_to_enclave(&mut dest[..]);
419 /// Copies the value from user memory into a vector in enclave memory.
420 pub fn to_enclave(&self) -> Vec<T> {
421 let mut ret = Vec::with_capacity(self.len());
422 self.copy_to_enclave_vec(&mut ret);
426 /// Returns an iterator over the slice.
427 pub fn iter(&self) -> Iter<T>
428 where T: UserSafe // FIXME: should be implied by [T]: UserSafe?
431 Iter((&*self.as_raw_ptr()).iter())
435 /// Returns an iterator that allows modifying each value.
436 pub fn iter_mut(&mut self) -> IterMut<T>
437 where T: UserSafe // FIXME: should be implied by [T]: UserSafe?
440 IterMut((&mut*self.as_raw_mut_ptr()).iter_mut())
445 /// Immutable user slice iterator
447 /// This struct is created by the `iter` method on `UserRef<[T]>`.
448 #[unstable(feature = "sgx_platform", issue = "56975")]
449 pub struct Iter<'a, T: 'a + UserSafe>(slice::Iter<'a, T>);
451 #[unstable(feature = "sgx_platform", issue = "56975")]
452 impl<'a, T: UserSafe> Iterator for Iter<'a, T> {
453 type Item = &'a UserRef<T>;
456 fn next(&mut self) -> Option<Self::Item> {
458 self.0.next().map(|e| UserRef::from_ptr(e))
463 /// Mutable user slice iterator
465 /// This struct is created by the `iter_mut` method on `UserRef<[T]>`.
466 #[unstable(feature = "sgx_platform", issue = "56975")]
467 pub struct IterMut<'a, T: 'a + UserSafe>(slice::IterMut<'a, T>);
469 #[unstable(feature = "sgx_platform", issue = "56975")]
470 impl<'a, T: UserSafe> Iterator for IterMut<'a, T> {
471 type Item = &'a mut UserRef<T>;
474 fn next(&mut self) -> Option<Self::Item> {
476 self.0.next().map(|e| UserRef::from_mut_ptr(e))
481 #[unstable(feature = "sgx_platform", issue = "56975")]
482 impl<T: ?Sized> Deref for User<T> where T: UserSafe {
483 type Target = UserRef<T>;
485 fn deref(&self) -> &Self::Target {
486 unsafe { &*self.0.as_ptr() }
490 #[unstable(feature = "sgx_platform", issue = "56975")]
491 impl<T: ?Sized> DerefMut for User<T> where T: UserSafe {
492 fn deref_mut(&mut self) -> &mut Self::Target {
493 unsafe { &mut*self.0.as_ptr() }
497 #[unstable(feature = "sgx_platform", issue = "56975")]
498 impl<T: ?Sized> Drop for User<T> where T: UserSafe {
501 let ptr = (*self.0.as_ptr()).0.get();
502 super::free(ptr as _, mem::size_of_val(&mut*ptr), T::align_of());
507 #[unstable(feature = "sgx_platform", issue = "56975")]
508 impl<T: CoerceUnsized<U>, U> CoerceUnsized<UserRef<U>> for UserRef<T> {}
510 #[unstable(feature = "sgx_platform", issue = "56975")]
511 impl<T, I: SliceIndex<[T]>> Index<I> for UserRef<[T]> where [T]: UserSafe, I::Output: UserSafe {
512 type Output = UserRef<I::Output>;
515 fn index(&self, index: I) -> &UserRef<I::Output> {
517 UserRef::from_ptr(index.index(&*self.as_raw_ptr()))
522 #[unstable(feature = "sgx_platform", issue = "56975")]
523 impl<T, I: SliceIndex<[T]>> IndexMut<I> for UserRef<[T]> where [T]: UserSafe, I::Output: UserSafe {
525 fn index_mut(&mut self, index: I) -> &mut UserRef<I::Output> {
527 UserRef::from_mut_ptr(index.index_mut(&mut*self.as_raw_mut_ptr()))
532 #[unstable(feature = "sgx_platform", issue = "56975")]
533 impl UserRef<super::raw::ByteBuffer> {
534 /// Copies the user memory range pointed to by the user `ByteBuffer` to
538 /// This function panics if:
540 /// * The pointer in the user `ByteBuffer` is null
541 /// * The pointed-to range in the user `ByteBuffer` is not in user memory
542 pub fn copy_user_buffer(&self) -> Vec<u8> {
544 let buf = self.to_enclave();
546 User::from_raw_parts(buf.data as _, buf.len).to_enclave()
548 // Mustn't look at `data` or call `free` if `len` is `0`.
549 Vec::with_capacity(0)