feat(boot): gatekeeper gates boot (init→UI→gatekeeper→data); keystore disk + virtio-rng discovery; terminal READ_SECRET; storage SET_KEY; PageCount ≤8192, alloc cap gone; device window 0x01D0_0000; test-qemu types passcode over 2 boots

crates/servers/gatekeeper/src/lib.rs

@@ -7,8 +7,78 @@
 
 extern crate alloc;
 
+pub mod devices;
 pub mod flow;
 
 #[cfg(test)]
 #[path = "tests/mod.rs"]
 mod tests;
+
+use alloc::vec;
+use keystore::{Block, KdfParams};
+use libkos::syscall::{self, Received};
+use types::bounded::CapSlot;
+use types::gatekeeper::{KEY, UNLOCK, reply};
+
+/// Where init's manifest put them: its own endpoint (devices arrive on
+/// it, then init's calls), then the terminal.
+const EP: CapSlot = CapSlot::const_new(0);
+const TERMINAL: CapSlot = CapSlot::const_new(1);
+
+/// Answers init's next call, if it is `op`, with `words`.
+fn answer(op: usize, words: [usize; 4]) -> bool {
+    loop {
+        match syscall::receive_msg(EP) {
+            Ok(Received::Call { badge: 0, words: [w, ..], .. }) if w == op => {
+                return syscall::reply(words, None).is_ok();
+            }
+            // Anyone else, or anything else: refused.
+            Ok(Received::Call { .. }) => {
+                let _ = syscall::reply([reply::FAILED, 0, 0, 0], None);
+            }
+            Ok(_) => {}
+            Err(_) => return false,
+        }
+    }
+}
+
+pub fn run() -> ! {
+    // Init hands over the keystore disk, then the randomness device.
+    let keystore = libkos::device::receive_device(EP).mmio.and_then(driver_block_virtio::VirtioBlockDevice::new);
+    let random = libkos::device::receive_device(EP).mmio.and_then(driver_rng_virtio::VirtioRng::new);
+    let (Some(keystore), Some(random)) = (keystore, random) else {
+        libkos::println!("gatekeeper: no keystore or no randomness, nothing to unlock with");
+        let _ = answer(UNLOCK, [reply::FAILED, 0, 0, 0]);
+        syscall::exit();
+    };
+    let mut memory = vec![Block::default(); KdfParams::DEFAULT.memory_kib as usize];
+    libkos::println!("gatekeeper: waiting for the owner");
+    let key = flow::run(
+        &mut devices::Disk(keystore),
+        &mut devices::Hardware(random),
+        &mut devices::Terminal(TERMINAL),
+        KdfParams::DEFAULT,
+        &mut memory,
+    );
+    // The guesses' working memory goes before anything else happens.
+    for b in memory.iter_mut() {
+        *b = Block::default();
+    }
+    drop(memory);
+    match key {
+        Ok(key) => {
+            libkos::println!("gatekeeper: unlocked");
+            libkos::terminal::clear(TERMINAL);
+            let word = |i: usize| usize::from_le_bytes(key.0[i * 8..i * 8 + 8].try_into().unwrap_or([0; 8]));
+            if answer(UNLOCK, [reply::OK, 0, 0, 0]) {
+                let _ = answer(KEY, [word(0), word(1), word(2), word(3)]);
+            }
+        }
+        Err(why) => {
+            libkos::println!("gatekeeper: cannot go on: {:?}", why);
+            let _ = answer(UNLOCK, [reply::FAILED, 0, 0, 0]);
+        }
+    }
+    // Its capabilities go with it.
+    syscall::exit()
+}