summaryrefslogtreecommitdiffstats
path: root/third_party/rust/fuchsia-zircon/src/cprng.rs
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 09:22:09 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 09:22:09 +0000
commit43a97878ce14b72f0981164f87f2e35e14151312 (patch)
tree620249daf56c0258faa40cbdcf9cfba06de2a846 /third_party/rust/fuchsia-zircon/src/cprng.rs
parentInitial commit. (diff)
downloadfirefox-upstream.tar.xz
firefox-upstream.zip
Adding upstream version 110.0.1.upstream/110.0.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/fuchsia-zircon/src/cprng.rs')
-rw-r--r--third_party/rust/fuchsia-zircon/src/cprng.rs68
1 files changed, 68 insertions, 0 deletions
diff --git a/third_party/rust/fuchsia-zircon/src/cprng.rs b/third_party/rust/fuchsia-zircon/src/cprng.rs
new file mode 100644
index 0000000000..433ed26d9e
--- /dev/null
+++ b/third_party/rust/fuchsia-zircon/src/cprng.rs
@@ -0,0 +1,68 @@
+use {Status, ok, sys};
+
+/// Draw random bytes from the kernel's CPRNG to fill the given buffer. Returns the actual number of
+/// bytes drawn, which may sometimes be less than the size of the buffer provided.
+///
+/// The buffer must have length less than `ZX_CPRNG_DRAW_MAX_LEN`.
+///
+/// Wraps the
+/// [zx_cprng_draw](https://fuchsia.googlesource.com/zircon/+/HEAD/docs/syscalls/cprng_draw.md)
+/// syscall.
+pub fn cprng_draw(buffer: &mut [u8]) -> Result<usize, Status> {
+ let mut actual = 0;
+ let status = unsafe { sys::zx_cprng_draw(buffer.as_mut_ptr(), buffer.len(), &mut actual) };
+ ok(status).map(|()| actual)
+}
+
+/// Mix the given entropy into the kernel CPRNG.
+///
+/// The buffer must have length less than `ZX_CPRNG_ADD_ENTROPY_MAX_LEN`.
+///
+/// Wraps the
+/// [zx_cprng_add_entropy](https://fuchsia.googlesource.com/zircon/+/HEAD/docs/syscalls/cprng_add_entropy.md)
+/// syscall.
+pub fn cprng_add_entropy(buffer: &[u8]) -> Result<(), Status> {
+ let status = unsafe { sys::zx_cprng_add_entropy(buffer.as_ptr(), buffer.len()) };
+ ok(status)
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ #[test]
+ fn cprng() {
+ let mut buffer = [0; 20];
+ assert_eq!(cprng_draw(&mut buffer), Ok(20));
+ let mut first_zero = 0;
+ let mut last_zero = 0;
+ for _ in 0..30 {
+ let mut buffer = [0; 20];
+ assert_eq!(cprng_draw(&mut buffer), Ok(20));
+ if buffer[0] == 0 {
+ first_zero += 1;
+ }
+ if buffer[19] == 0 {
+ last_zero += 1;
+ }
+ }
+ assert_ne!(first_zero, 30);
+ assert_ne!(last_zero, 30);
+ }
+
+ #[test]
+ fn cprng_too_large() {
+ let mut buffer = [0; sys::ZX_CPRNG_DRAW_MAX_LEN + 1];
+ assert_eq!(cprng_draw(&mut buffer), Err(Status::INVALID_ARGS));
+
+ for mut s in buffer.chunks_mut(sys::ZX_CPRNG_DRAW_MAX_LEN) {
+ assert_eq!(cprng_draw(&mut s), Ok(s.len()));
+ }
+ }
+
+ #[test]
+ fn cprng_add() {
+ let buffer = [0, 1, 2];
+ assert_eq!(cprng_add_entropy(&buffer), Ok(()));
+ }
+} \ No newline at end of file