LKML: alistair23@gmail ...: [RFC v3 01/27] rust: add untrusted data abstraction

From: Benno Lossin <benno.lossin@proton.me>

When reading data from userspace, hardware or other external untrusted
sources, the data must be validated before it is used for logic within
the kernel. This abstraction provides a generic newtype wrapper
`Untrusted`; it prevents direct access to the inner type. The only way
to use the underlying data is to call `.validate()` on such a value.

Doing so utilizes the new `Validate` trait that is responsible for all
of the validation logic. This trait gives access to the inner value of
`Untrusted` by means of another newtype wrapper `Unvalidated`. In
contrast to `Untrusted`, `Unvalidated` allows direct access and
additionally provides several helper functions for slices.

Having these two different newtype wrappers is an idea from Simona
Vetter. It has several benefits: it fully prevents safe access to the
underlying value of `Untrusted` without going through the `Validate`
API. Additionally, it allows one to grep for validation logic by simply
looking for `Unvalidated<`.

Any API that reads data from an untrusted source should return
`Untrusted<T>` where `T` is the type of the underlying untrusted data.
This generic allows other abstractions to return their custom type
wrapped by `Untrusted`, signaling to the caller that the data must be
validated before use. This allows those abstractions to be used both in
a trusted and untrusted manner, increasing their generality.
Additionally, using the arbitrary self types feature, APIs can be
designed to explicitly read untrusted data:

impl MyCustomDataSource {
pub fn read(self: &Untrusted<Self>) -> &Untrusted<[u8]>;
}

Cc: Simona Vetter <simona.vetter@ffwll.ch>
Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Message-ID: <20240925205244.873020-2-benno.lossin@proton.me>
---
rust/kernel/lib.rs | 1 +
rust/kernel/validate.rs | 605 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 606 insertions(+)
create mode 100644 rust/kernel/validate.rs

diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 696f62f85eb5..915499704405 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -154,6 +154,7 @@
pub mod uaccess;
#[cfg(CONFIG_USB = "y")]
pub mod usb;
+pub mod validate;
pub mod workqueue;
pub mod xarray;

diff --git a/rust/kernel/validate.rs b/rust/kernel/validate.rs
new file mode 100644
index 000000000000..ae0aa20e27b4
--- /dev/null
+++ b/rust/kernel/validate.rs
@@ -0,0 +1,605 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Types for handling and validating untrusted data.
+//!
+//! # Overview
+//!
+//! Untrusted data is marked using the [`Untrusted<T>`] type. See [Rationale](#rationale) for the
+//! reasons to mark untrusted data throughout the kernel. It is a totally opaque wrapper, it is not
+//! possible to read the data inside; but it is possible to [`Untrusted::write`] into it.
+//!
+//! The only way to "access" the data inside an [`Untrusted<T>`] is to [`Untrusted::validate`] it;
+//! turning it into a different form using the [`Validate`] trait. That trait receives the data in
+//! the form of [`Unvalidated<T>`], which in contrast to [`Untrusted<T>`], allows access to the
+//! underlying data. It additionally provides several utility functions to simplify validation.
+//!
+//! # Rationale
+//!
+//! When reading data from an untrusted source, it must be validated before it can be used for
+//! logic. For example, this is a very bad idea:
+//!
+//! ```
+//! # fn read_bytes_from_network() -> Box<[u8]> {
+//! # Box::new([1, 0], kernel::alloc::flags::GFP_KERNEL).unwrap()
+//! # }
+//! let bytes: Box<[u8]> = read_bytes_from_network();
+//! let data_index = bytes[0];
+//! let data = bytes[usize::from(data_index)];
+//! ```
+//!
+//! While this will not lead to a memory violation (because the array index checks the bounds), it
+//! might result in a kernel panic. For this reason, all untrusted data must be wrapped in
+//! [`Untrusted<T>`]. This type only allows validating the data or passing it along, since copying
+//! data from one userspace buffer into another is allowed for untrusted data.
+
+use crate::prelude::Init;
+use core::{
+ mem::MaybeUninit,
+ ops::{Index, IndexMut},
+ ptr, slice,
+};
+
+/// Untrusted data of type `T`.
+///
+/// When reading data from userspace, hardware or other external untrusted sources, the data must
+/// be validated before it is used for logic within the kernel. To do so, the [`validate()`]
+/// function exists and uses the [`Validate`] trait.
+///
+/// Also see the [module] description.
+///
+/// [`validate()`]: Self::validate
+/// [module]: self
+#[repr(transparent)]
+pub struct Untrusted<T: ?Sized>(Unvalidated<T>);
+
+impl<T: ?Sized> Untrusted<T> {
+ /// Marks the given value as untrusted.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use kernel::validate::Untrusted;
+ ///
+ /// # mod bindings { pub(crate) unsafe fn read_foo_info() -> [u8; 4] { todo!() } };
+ /// fn read_foo_info() -> Untrusted<[u8; 4]> {
+ /// // SAFETY: just an FFI call without preconditions.
+ /// Untrusted::new(unsafe { bindings::read_foo_info() })
+ /// }
+ /// ```
+ pub fn new(value: T) -> Self
+ where
+ T: Sized,
+ {
+ Self(Unvalidated::new(value))
+ }
+
+ /// Marks the value behind the reference as untrusted.
+ ///
+ /// # Examples
+ ///
+ /// In this imaginary example there exists the `foo_hardware` struct on the C side, as well as
+ /// a `foo_hardware_read` function that reads some data directly from the hardware.
+ /// ```
+ /// use kernel::{error, types::Opaque, validate::Untrusted};
+ /// use core::ptr;
+ ///
+ /// # #[allow(non_camel_case_types)]
+ /// # mod bindings {
+ /// # pub(crate) struct foo_hardware;
+ /// # pub(crate) unsafe fn foo_hardware_read(_foo: *mut foo_hardware, _len: &mut usize) -> *mut u8 {
+ /// # todo!()
+ /// # }
+ /// # }
+ /// struct Foo(Opaque<bindings::foo_hardware>);
+ ///
+ /// impl Foo {
+ /// fn read(&mut self, mut len: usize) -> Result<&Untrusted<[u8]>> {
+ /// // SAFETY: just an FFI call without preconditions.
+ /// let data: *mut u8 = unsafe { bindings::foo_hardware_read(self.0.get(), &mut len) };
+ /// let data = error::from_err_ptr(data)?;
+ /// let data = ptr::slice_from_raw_parts(data, len);
+ /// // SAFETY: `data` returned by `foo_hardware_read` is valid for reads as long as the
+ /// // `foo_hardware` object exists. That function updated the
+ /// let data = unsafe { &*data };
+ /// Ok(Untrusted::new_ref(data))
+ /// }
+ /// }
+ /// ```
+ pub fn new_ref(value: &T) -> &Self {
+ let ptr: *const T = value;
+ // CAST: `Self` and `Unvalidated` are `repr(transparent)` and contain a `T`.
+ let ptr = ptr as *const Self;
+ // SAFETY: `ptr` came from a shared reference valid for `'a`.
+ unsafe { &*ptr }
+ }
+
+ /// Marks the value behind the reference as untrusted.
+ ///
+ /// # Examples
+ ///
+ /// In this imaginary example there exists the `foo_hardware` struct on the C side, as well as
+ /// a `foo_hardware_read` function that reads some data directly from the hardware.
+ /// ```
+ /// use kernel::{error, types::Opaque, validate::Untrusted};
+ /// use core::ptr;
+ ///
+ /// # #[allow(non_camel_case_types)]
+ /// # mod bindings {
+ /// # pub(crate) struct foo_hardware;
+ /// # pub(crate) unsafe fn foo_hardware_read(_foo: *mut foo_hardware, _len: &mut usize) -> *mut u8 {
+ /// # todo!()
+ /// # }
+ /// # }
+ /// struct Foo(Opaque<bindings::foo_hardware>);
+ ///
+ /// impl Foo {
+ /// fn read(&mut self, mut len: usize) -> Result<&mut Untrusted<[u8]>> {
+ /// // SAFETY: just an FFI call without preconditions.
+ /// let data: *mut u8 = unsafe { bindings::foo_hardware_read(self.0.get(), &mut len) };
+ /// let data = error::from_err_ptr(data)?;
+ /// let data = ptr::slice_from_raw_parts_mut(data, len);
+ /// // SAFETY: `data` returned by `foo_hardware_read` is valid for reads as long as the
+ /// // `foo_hardware` object exists. That function updated the
+ /// let data = unsafe { &mut *data };
+ /// Ok(Untrusted::new_mut(data))
+ /// }
+ /// }
+ /// ```
+ pub fn new_mut(value: &mut T) -> &mut Self {
+ let ptr: *mut T = value;
+ // CAST: `Self` and `Unvalidated` are `repr(transparent)` and contain a `T`.
+ let ptr = ptr as *mut Self;
+ // SAFETY: `ptr` came from a mutable reference valid for `'a`.
+ unsafe { &mut *ptr }
+ }
+
+ /// Validates and parses the untrusted data.
+ ///
+ /// See the [`Validate`] trait on how to implement it.
+ pub fn validate<'a, V: Validate<&'a Unvalidated<T>>>(&'a self) -> Result<V, V::Err> {
+ V::validate(&self.0)
+ }
+
+ /// Validates and parses the untrusted data.
+ ///
+ /// See the [`Validate`] trait on how to implement it.
+ pub fn validate_mut<'a, V: Validate<&'a mut Unvalidated<T>>>(
+ &'a mut self,
+ ) -> Result<V, V::Err> {
+ V::validate(&mut self.0)
+ }
+
+ /// Sets the underlying untrusted value.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use kernel::validate::Untrusted;
+ ///
+ /// let mut untrusted = Untrusted::new(42);
+ /// untrusted.write(24);
+ /// ```
+ pub fn write(&mut self, value: impl Init<T>) {
+ let ptr: *mut T = &mut self.0 .0;
+ // SAFETY: `ptr` came from a mutable reference and the value is overwritten before it is
+ // read.
+ unsafe { ptr::drop_in_place(ptr) };
+ // SAFETY: `ptr` came from a mutable reference and the initializer cannot error.
+ match unsafe { value.__init(ptr) } {
+ Ok(()) => {}
+ Err(_) => unreachable!(),
+ }
+ }
+
+ /// Turns a slice of untrusted values into an untrusted slice of values.
+ pub fn transpose_slice(slice: &[Untrusted<T>]) -> &Untrusted<[T]>
+ where
+ T: Sized,
+ {
+ let ptr = slice.as_ptr().cast::<T>();
+ // SAFETY: `ptr` and `len` come from the same slice reference.
+ let slice = unsafe { slice::from_raw_parts(ptr, slice.len()) };
+ Untrusted::new_ref(slice)
+ }
+
+ /// Turns a slice of uninitialized, untrusted values into an untrusted slice of uninitialized
+ /// values.
+ pub fn transpose_slice_uninit(
+ slice: &[MaybeUninit<Untrusted<T>>],
+ ) -> &Untrusted<[MaybeUninit<T>]>
+ where
+ T: Sized,
+ {
+ let ptr = slice.as_ptr().cast::<MaybeUninit<T>>();
+ // SAFETY: `ptr` and `len` come from the same mutable slice reference.
+ let slice = unsafe { slice::from_raw_parts(ptr, slice.len()) };
+ Untrusted::new_ref(slice)
+ }
+
+ /// Turns a slice of uninitialized, untrusted values into an untrusted slice of uninitialized
+ /// values.
+ pub fn transpose_slice_uninit_mut(
+ slice: &mut [MaybeUninit<Untrusted<T>>],
+ ) -> &mut Untrusted<[MaybeUninit<T>]>
+ where
+ T: Sized,
+ {
+ // CAST: `MaybeUninit<T>` and `MaybeUninit<Untrusted<T>>` have the same layout.
+ let ptr = slice.as_mut_ptr().cast::<MaybeUninit<T>>();
+ // SAFETY: `ptr` and `len` come from the same mutable slice reference.
+ let slice = unsafe { slice::from_raw_parts_mut(ptr, slice.len()) };
+ Untrusted::new_mut(slice)
+ }
+}
+
+impl<T> Untrusted<MaybeUninit<T>> {
+ /// Sets the underlying untrusted value.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use kernel::validate::Untrusted;
+ ///
+ /// let mut untrusted = Untrusted::new(42);
+ /// untrusted.write(24);
+ /// ```
+ pub fn write_uninit<E>(&mut self, value: impl Init<T, E>) -> Result<&mut Untrusted<T>, E> {
+ let ptr: *mut MaybeUninit<T> = &mut self.0 .0;
+ // CAST: `MaybeUninit<T>` is `repr(transparent)`.
+ let ptr = ptr.cast::<T>();
+ // SAFETY: `ptr` came from a reference and if `Err` is returned, the underlying memory is
+ // considered uninitialized.
+ unsafe { value.__init(ptr) }.map(|()| {
+ let this = self.0.raw_mut();
+ // SAFETY: we initialized the memory above.
+ Untrusted::new_mut(unsafe { this.assume_init_mut() })
+ })
+ }
+}
+
+impl<T> Untrusted<[MaybeUninit<T>]> {
+ /// Sets the underlying untrusted value.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use kernel::validate::Untrusted;
+ ///
+ /// let mut untrusted = Untrusted::new(42);
+ /// untrusted.write(24);
+ /// ```
+ pub fn write_uninit_slice<E>(
+ &mut self,
+ value: impl Init<[T], E>,
+ ) -> Result<&mut Untrusted<[T]>, E> {
+ let ptr: *mut [MaybeUninit<T>] = &mut self.0 .0;
+ // CAST: `MaybeUninit<T>` is `repr(transparent)`.
+ let ptr = ptr as *mut [T];
+ // SAFETY: `ptr` came from a reference and if `Err` is returned, the underlying memory is
+ // considered uninitialized.
+ unsafe { value.__init(ptr) }.map(|()| {
+ let this = self.0.raw_mut().as_mut_ptr();
+ // CAST: `MaybeUninit<T>` is `repr(transparent)`.
+ let this = this.cast::<T>();
+ // SAFETY: `this` and `len` came from the same slice reference.
+ let this = unsafe { slice::from_raw_parts_mut(this, self.0.len()) };
+ Untrusted::new_mut(this)
+ })
+ }
+}
+
+/// Marks types that can be used as input to [`Validate::validate`].
+pub trait ValidateInput: private::Sealed + Sized {}
+
+mod private {
+ pub trait Sealed {}
+}
+
+impl<'a, T: ?Sized> private::Sealed for &'a Unvalidated<T> {}
+impl<'a, T: ?Sized> ValidateInput for &'a Unvalidated<T> {}
+
+impl<'a, T: ?Sized> private::Sealed for &'a mut Unvalidated<T> {}
+impl<'a, T: ?Sized> ValidateInput for &'a mut Unvalidated<T> {}
+
+/// Validates untrusted data.
+///
+/// # Examples
+///
+/// The simplest way to validate data is to just implement `Validate<&Unvalidated<[u8]>>` for the
+/// type that you wish to validate:
+///
+/// ```
+/// use kernel::{
+/// error::{code::EINVAL, Error},
+/// str::{CStr, CString},
+/// validate::{Unvalidated, Validate},
+/// };
+///
+/// struct Data {
+/// flags: u8,
+/// name: CString,
+/// }
+///
+/// impl Validate<&Unvalidated<[u8]>> for Data {
+/// type Err = Error;
+///
+/// fn validate(unvalidated: &Unvalidated<[u8]>) -> Result<Self, Self::Err> {
+/// let raw = unvalidated.raw();
+/// let (&flags, name) = raw.split_first().ok_or(EINVAL)?;
+/// let name = CStr::from_bytes_with_nul(name)?.to_cstring()?;
+/// Ok(Data { flags, name })
+/// }
+/// }
+/// ```
+///
+/// This approach copies the data and requires allocation. If you want to avoid the allocation and
+/// copying the data, you can borrow from the input like this:
+///
+/// ```
+/// use kernel::{
+/// error::{code::EINVAL, Error},
+/// str::CStr,
+/// validate::{Unvalidated, Validate},
+/// };
+///
+/// struct Data<'a> {
+/// flags: u8,
+/// name: &'a CStr,
+/// }
+///
+/// impl<'a> Validate<&'a Unvalidated<[u8]>> for Data<'a> {
+/// type Err = Error;
+///
+/// fn validate(unvalidated: &'a Unvalidated<[u8]>) -> Result<Self, Self::Err> {
+/// let raw = unvalidated.raw();
+/// let (&flags, name) = raw.split_first().ok_or(EINVAL)?;
+/// let name = CStr::from_bytes_with_nul(name)?;
+/// Ok(Data { flags, name })
+/// }
+/// }
+/// ```
+///
+/// If you need to in-place validate your data, you currently need to resort to `unsafe`:
+///
+/// ```
+/// use kernel::{
+/// error::{code::EINVAL, Error},
+/// str::CStr,
+/// validate::{Unvalidated, Validate},
+/// };
+/// use core::mem;
+///
+/// // Important: use `repr(C)`, this ensures a linear layout of this type.
+/// #[repr(C)]
+/// struct Data {
+/// version: u8,
+/// flags: u8,
+/// _reserved: [u8; 2],
+/// count: u64,
+/// // lots of other fields...
+/// }
+///
+/// impl Validate<&Unvalidated<[u8]>> for &Data {
+/// type Err = Error;
+///
+/// fn validate(unvalidated: &Unvalidated<[u8]>) -> Result<Self, Self::Err> {
+/// let raw = unvalidated.raw();
+/// if raw.len() < mem::size_of::<Data>() {
+/// return Err(EINVAL);
+/// }
+/// // can only handle version 0
+/// if raw[0] != 0 {
+/// return Err(EINVAL);
+/// }
+/// // version 0 only uses the lower 4 bits of flags
+/// if raw[1] & 0xf0 != 0 {
+/// return Err(EINVAL);
+/// }
+/// let ptr = raw.as_ptr();
+/// // CAST: `Data` only contains integers and has `repr(C)`.
+/// let ptr = ptr.cast::<Data>();
+/// // SAFETY: `ptr` came from a reference and the cast above is valid.
+/// Ok(unsafe { &*ptr })
+/// }
+/// }
+/// ```
+///
+/// To be able to modify the parsed data, while still supporting zero-copy, you can implement
+/// `Validate<&mut Unvalidated<[u8]>>`:
+///
+/// ```
+/// use kernel::{
+/// error::{code::EINVAL, Error},
+/// str::CStr,
+/// validate::{Unvalidated, Validate},
+/// };
+/// use core::mem;
+///
+/// // Important: use `repr(C)`, this ensures a linear layout of this type.
+/// #[repr(C)]
+/// struct Data {
+/// version: u8,
+/// flags: u8,
+/// _reserved: [u8; 2],
+/// count: u64,
+/// // lots of other fields...
+/// }
+///
+/// impl Validate<&mut Unvalidated<[u8]>> for &Data {
+/// type Err = Error;
+///
+/// fn validate(unvalidated: &mut Unvalidated<[u8]>) -> Result<Self, Self::Err> {
+/// let raw = unvalidated.raw_mut();
+/// if raw.len() < mem::size_of::<Data>() {
+/// return Err(EINVAL);
+/// }
+/// match raw[0] {
+/// 0 => {},
+/// 1 => {
+/// // version 1 implicitly sets the first bit.
+/// raw[1] |= 1;
+/// },
+/// // can only handle version 0 and 1
+/// _ => return Err(EINVAL),
+/// }
+/// // version 0 and 1 only use the lower 4 bits of flags
+/// if raw[1] & 0xf0 != 0 {
+/// return Err(EINVAL);
+/// }
+/// if raw[1] == 0 {}
+/// let ptr = raw.as_ptr();
+/// // CAST: `Data` only contains integers and has `repr(C)`.
+/// let ptr = ptr.cast::<Data>();
+/// // SAFETY: `ptr` came from a reference and the cast above is valid.
+/// Ok(unsafe { &*ptr })
+/// }
+/// }
+/// ```
+pub trait Validate<I: ValidateInput>: Sized {
+ /// Validation error.
+ type Err;
+
+ /// Validate the given untrusted data and parse it into the output type.
+ fn validate(unvalidated: I) -> Result<Self, Self::Err>;
+}
+
+/// Unvalidated data of type `T`.
+#[repr(transparent)]
+pub struct Unvalidated<T: ?Sized>(T);
+
+impl<T: ?Sized> Unvalidated<T> {
+ fn new(value: T) -> Self
+ where
+ T: Sized,
+ {
+ Self(value)
+ }
+
+ fn new_ref(value: &T) -> &Self {
+ let ptr: *const T = value;
+ // CAST: `Self` is `repr(transparent)` and contains a `T`.
+ let ptr = ptr as *const Self;
+ // SAFETY: `ptr` came from a mutable reference valid for `'a`.
+ unsafe { &*ptr }
+ }
+
+ fn new_mut(value: &mut T) -> &mut Self {
+ let ptr: *mut T = value;
+ // CAST: `Self` is `repr(transparent)` and contains a `T`.
+ let ptr = ptr as *mut Self;
+ // SAFETY: `ptr` came from a mutable reference valid for `'a`.
+ unsafe { &mut *ptr }
+ }
+
+ /// Validates and parses the untrusted data.
+ ///
+ /// See the [`Validate`] trait on how to implement it.
+ pub fn validate_ref<'a, V: Validate<&'a Unvalidated<T>>>(&'a self) -> Result<V, V::Err> {
+ V::validate(self)
+ }
+
+ /// Validates and parses the untrusted data.
+ ///
+ /// See the [`Validate`] trait on how to implement it.
+ pub fn validate_mut<'a, V: Validate<&'a mut Unvalidated<T>>>(
+ &'a mut self,
+ ) -> Result<V, V::Err> {
+ V::validate(self)
+ }
+
+ /// Gives immutable access to the underlying value.
+ pub fn raw(&self) -> &T {
+ &self.0
+ }
+
+ /// Gives mutable access to the underlying value.
+ pub fn raw_mut(&mut self) -> &mut T {
+ &mut self.0
+ }
+}
+
+impl<T, I> Index<I> for Unvalidated<[T]>
+where
+ I: slice::SliceIndex<[T]>,
+{
+ type Output = Unvalidated<I::Output>;
+
+ fn index(&self, index: I) -> &Self::Output {
+ Unvalidated::new_ref(self.0.index(index))
+ }
+}
+
+impl<T, I> IndexMut<I> for Unvalidated<[T]>
+where
+ I: slice::SliceIndex<[T]>,
+{
+ fn index_mut(&mut self, index: I) -> &mut Self::Output {
+ Unvalidated::new_mut(self.0.index_mut(index))
+ }
+}
+
+/// Immutable unvalidated slice iterator.
+pub struct Iter<'a, T>(slice::Iter<'a, T>);
+
+/// Mutable unvalidated slice iterator.
+pub struct IterMut<'a, T>(slice::IterMut<'a, T>);
+
+impl<'a, T> Iterator for Iter<'a, T> {
+ type Item = &'a Unvalidated<T>;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.0.next().map(Unvalidated::new_ref)
+ }
+}
+
+impl<'a, T> IntoIterator for &'a Unvalidated<[T]> {
+ type Item = &'a Unvalidated<T>;
+ type IntoIter = Iter<'a, T>;
+
+ fn into_iter(self) -> Self::IntoIter {
+ Iter(self.0.iter())
+ }
+}
+
+impl<'a, T> Iterator for IterMut<'a, T> {
+ type Item = &'a mut Unvalidated<T>;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.0.next().map(Unvalidated::new_mut)
+ }
+}
+
+impl<'a, T> IntoIterator for &'a mut Unvalidated<[T]> {
+ type Item = &'a mut Unvalidated<T>;
+ type IntoIter = IterMut<'a, T>;
+
+ fn into_iter(self) -> Self::IntoIter {
+ IterMut(self.0.iter_mut())
+ }
+}
+
+impl<T> Unvalidated<[T]> {
+ /// Returns the number of elements in the underlying slice.
+ pub fn len(&self) -> usize {
+ self.0.len()
+ }
+
+ /// Returns true if the underlying slice has a length of 0.
+ pub fn is_empty(&self) -> bool {
+ self.0.is_empty()
+ }
+
+ /// Iterates over all items and validates each of them individually.
+ pub fn validate_iter<'a, V: Validate<&'a Unvalidated<T>>>(
+ &'a self,
+ ) -> impl Iterator<Item = Result<V, V::Err>> + 'a {
+ self.into_iter().map(|item| V::validate(item))
+ }
+
+ /// Iterates over all items and validates each of them individually.
+ pub fn validate_iter_mut<'a, V: Validate<&'a mut Unvalidated<T>>>(
+ &'a mut self,
+ ) -> impl Iterator<Item = Result<V, V::Err>> + 'a {
+ self.into_iter().map(|item| V::validate(item))
+ }
+}
--
2.52.0