[pbs-devel] [PATCH proxmox-backup 1/1] fix #6939: acme: accept HTTP 204 from newNonce endpoint

[Samuel Rufinatscha]

When registering an ACME account, PBS fetches a fresh nonce by issuing a
HEAD request to the server's newNonce URL. Until now we assumed this
request would return HTTP 200 OK.

In practice, some ACME servers respond with HTTP 204 No Content for this
HEAD request while still providing a valid Replay-Nonce header. This
causes PBS to abort registration with "ACME server responded with
unexpected status code: 204", even though the server would otherwise
issue certificates correctly.

Adjust the ACME client code in PBS to accept both 200 OK and 204 No
Content as successful results for the newNonce step. We continue to
reject other status codes so we don't silently accept arbitrary 2xx
responses.

This restores interoperability with ACME servers that send 204 for
newNonce, and aligns PBS' behavior with the updated proxmox-acme library
as well as PVE's more tolerant ACME client.

Fixes: #6939
Signed-off-by: Samuel Rufinatscha <s.rufinatscha at proxmox.com>
---
 src/acme/client.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/acme/client.rs b/src/acme/client.rs
index 1c12a4b9..0dabf676 100644
--- a/src/acme/client.rs
+++ b/src/acme/client.rs
@@ -530,7 +530,7 @@ impl AcmeClient {
         };
 
         if parts.status.is_success() {
-            if status != request.expected {
+            if !request.expected.contains(&status) {
                 return Err(Error::InvalidApi(format!(
                     "ACME server responded with unexpected status code: {:?}",
                     parts.status
@@ -609,7 +609,7 @@ impl AcmeClient {
                 method: "GET",
                 content_type: "",
                 body: String::new(),
-                expected: 200,
+                expected: vec![200],
             },
             nonce,
         )
@@ -657,7 +657,7 @@ impl AcmeClient {
                 method: "HEAD",
                 content_type: "",
                 body: String::new(),
-                expected: 200,
+                expected: vec![200, 204],
             },
             nonce,
         )
-- 
2.47.3