Rust 1.83

[ArthurHeymans]

The goal of updating the rust library is to be able to use Mldsa from
rustCrypto repo: RustCrypto/signatures#877

The goal of using this code is to replace openssl to generate TBS and
CSR tempaltes. Openssl does not yet support Mldsa

The minimum required rust version is 1.81.

It looks like this toolchain needs a lot more stack than 1.70.

Rust 1.83 warns about unused stuff a lot more often which is addressed
in this commit.

This also updates DPE to compile without warnings and errors.
The changes are on github.com/caliptra-dpe but is not in the main
branch.

[jhand2]

This commit isn't upstream

[ArthurHeymans]

I added a comment in the PR description. Let me know how you think this should be dealt with.

[jhand2]

Let's merge the caliptra-dpe PR first and then use the upstream commit. It looks like there's an open comment from zach on that one.

[jhand2]

Can you update the PR description with the motivation for doing this?

In general, all PRs should have descriptions.

Also, this PR seems to have 2 classes of changes:

1. Things required because the compiler version changed (e.g. formatting, new clippy annotations)
2. Things that leverage new rust features that are now available.

Ideally all the things in (2) would be in a separate PR.

[swenson]

There seem to be some unrelated changes in this PR related to the manifest-based auth and ROM size changes.

[swenson]

Why does the stack and ROM size need to change in this PR?

[ArthurHeymans]

So it looks like with the newer toolchain significantly more stack is used. The stack overflow detection code in the emulator tripped on it and this was the minimal increase necessary.

[swenson]

This also seems unrelated to upgrading to Rust 1.83

[ArthurHeymans]

It's unused and rust 1.83 complains about it.

[ArthurHeymans]

Can you update the PR description with the motivation for doing this?

In general, all PRs should have descriptions.

Also, this PR seems to have 2 classes of changes:

1. Things required because the compiler version changed (e.g. formatting, new clippy annotations)
2. Things that leverage new rust features that are now available.

Ideally all the things in (2) would be in a separate PR.

This PR only attempts to fix warnings and errors with the newer toolchain. I added some motivation documentation to the PR.

[swenson]

This update appears to add a panic because Rust can't prove the indexes are correct in a ufmt macro. This should fix it I think:

diff --git a/drivers/src/printer.rs b/drivers/src/printer.rs
index 4b6d86c9..45f47e23 100644
--- a/drivers/src/printer.rs
+++ b/drivers/src/printer.rs
@@ -68,8 +68,19 @@ impl uDisplay for HexBytes<'_> {
     where
         W: uWrite + ?Sized,
     {
-        for byte in self.0.iter() {
-            ufmt::uwrite!(f, "{:02X}", *byte)?;
+        for &x in self.0.iter() {
+            let c = x >> 4;
+            if c < 10 {
+                f.write_char((c + b'0') as char)?;
+            } else {
+                f.write_char((c - 10 + b'A') as char)?;
+            }
+            let c = x & 0xf;
+            if c < 10 {
+                f.write_char((c + b'0') as char)?;
+            } else {
+                f.write_char((c - 10 + b'A') as char)?;
+            }
         }
         Ok(())
     }