This patch adds basic abstractions for random number generator API,
wrapping crypto_rng structure.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxx>
---
rust/bindings/bindings_helper.h | 1 +
rust/helpers.c | 12 ++++
rust/kernel/crypto.rs | 1 +
rust/kernel/crypto/rng.rs | 101 ++++++++++++++++++++++++++++++++
4 files changed, 115 insertions(+)
create mode 100644 rust/kernel/crypto/rng.rs
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 2f198c6d5de5..089ac38c6461 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -7,6 +7,7 @@
*/
#include <crypto/hash.h>
+#include <crypto/rng.h>
#include <linux/errname.h>
#include <linux/slab.h>
#include <linux/refcount.h>
diff --git a/rust/helpers.c b/rust/helpers.c
index 7966902ed8eb..e4dcd611738f 100644
--- a/rust/helpers.c
+++ b/rust/helpers.c
@@ -19,6 +19,7 @@
*/
#include <crypto/hash.h>
+#include <crypto/rng.h>
#include <linux/bug.h>
#include <linux/build_bug.h>
#include <linux/err.h>
@@ -52,6 +53,17 @@ int rust_helper_crypto_shash_init(struct shash_desc *desc) {
return crypto_shash_init(desc);
}
EXPORT_SYMBOL_GPL(rust_helper_crypto_shash_init);
+
+void rust_helper_crypto_free_rng(struct crypto_rng *tfm) {
+ crypto_free_rng(tfm);
+}
+EXPORT_SYMBOL_GPL(rust_helper_crypto_free_rng);
+
+int rust_helper_crypto_rng_generate(struct crypto_rng *tfm, const u8 *src,
+ unsigned int slen, u8 *dst, unsigned int dlen) {
+ return crypto_rng_generate(tfm, src, slen, dst, dlen);
+}
+EXPORT_SYMBOL_GPL(rust_helper_crypto_rng_generate);
#endif
__noreturn void rust_helper_BUG(void)
diff --git a/rust/kernel/crypto.rs b/rust/kernel/crypto.rs
index f80dd7bd3381..a1995e6c85d4 100644
--- a/rust/kernel/crypto.rs
+++ b/rust/kernel/crypto.rs
@@ -3,3 +3,4 @@
//! Cryptography.
pub mod hash;
+pub mod rng;
diff --git a/rust/kernel/crypto/rng.rs b/rust/kernel/crypto/rng.rs
new file mode 100644
index 000000000000..683f5ee464ce
--- /dev/null
+++ b/rust/kernel/crypto/rng.rs
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Random number generator.
+//!
+//! C headers: [`include/crypto/rng.h`](../../../../include/crypto/rng.h)
+
+use crate::{
+ error::{code::EINVAL, from_err_ptr, to_result, Result},
+ str::CStr,
+};
+
+/// Type of Random number generator.
+///
+/// # Invariants
+///
+/// The pointer is valid.
+enum RngType {
+ /// Uses `crypto_default_rng`
+ // We don't need to keep an pointer for the default but simpler.
+ Default(*mut bindings::crypto_rng),
+
+ /// Allocated via `crypto_alloc_rng.
+ Allocated(*mut bindings::crypto_rng),
+}
+
+/// Corresponds to the kernel's `struct crypto_rng`.
+pub struct Rng(RngType);
+
+impl Drop for Rng {
+ fn drop(&mut self) {
+ match self.0 {
+ RngType::Default(_) => {
+ // SAFETY: it's safe because `crypto_get_default_rng()` was called during
+ // the initialization.
+ unsafe {
+ bindings::crypto_put_default_rng();
+ }
+ }
+ RngType::Allocated(ptr) => {
+ // SAFETY: The type invariants of `RngType` guarantees that the pointer is valid.
+ unsafe { bindings::crypto_free_rng(ptr) };
+ }
+ }
+ }
+}
+
+impl Rng {
+ /// Creates a [`Rng`] instance.
+ pub fn new(name: &CStr, t: u32, mask: u32) -> Result<Self> {
+ // SAFETY: There are no safety requirements for this FFI call.
+ let ptr = unsafe { from_err_ptr(bindings::crypto_alloc_rng(name.as_char_ptr(), t, mask)) }?;
+ // INVARIANT: `ptr` is valid and non-null since `crypto_alloc_rng`
+ // returned a valid pointer which was null-checked.
+ Ok(Self(RngType::Allocated(ptr)))
+ }
+
+ /// Creates a [`Rng`] instance with a default algorithm.
+ pub fn new_with_default() -> Result<Self> {
+ // SAFETY: There are no safety requirements for this FFI call.
+ to_result(unsafe { bindings::crypto_get_default_rng() })?;
+ // INVARIANT: The C API guarantees that `crypto_default_rng` is valid until
+ // `crypto_put_default_rng` is called.
+ Ok(Self(RngType::Default(unsafe {
+ bindings::crypto_default_rng
+ })))
+ }
+
+ /// Get a random number.
+ pub fn generate(&mut self, src: &[u8], dst: &mut [u8]) -> Result {
+ if src.len() > u32::MAX as usize || dst.len() > u32::MAX as usize {
+ return Err(EINVAL);
+ }
+ let ptr = match self.0 {
+ RngType::Default(ptr) => ptr,
+ RngType::Allocated(ptr) => ptr,
+ };
+ // SAFETY: The type invariants of `RngType' guarantees that the pointer is valid.
+ to_result(unsafe {
+ bindings::crypto_rng_generate(
+ ptr,
+ src.as_ptr(),
+ src.len() as u32,
+ dst.as_mut_ptr(),
+ dst.len() as u32,
+ )
+ })
+ }
+
+ /// Re-initializes the [`Rng`] instance.
+ pub fn reset(&mut self, seed: &[u8]) -> Result {
+ if seed.len() > u32::MAX as usize {
+ return Err(EINVAL);
+ }
+ let ptr = match self.0 {
+ RngType::Default(ptr) => ptr,
+ RngType::Allocated(ptr) => ptr,
+ };
+ // SAFETY: The type invariants of `RngType' guarantees that the pointer is valid.
+ to_result(unsafe { bindings::crypto_rng_reset(ptr, seed.as_ptr(), seed.len() as u32) })
+ }
+}
--
2.34.1
