ouroboros/src/lib, branch be

build: Make re-key watermark configurable

2026-06-29T06:33:00+00:00

KEY_REKEY_WM_CHECK_BITS now controls the watermark check, once per 2^n flow writes (FLOW_WM_CHECK in dev.c). Now the configuration check (check watermark < outstanding packets) is contained in lib.cmake instead of assuming the value of FLOW_WM_CHECK. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Wipe unpacked session key after copy

2026-06-29T06:33:00+00:00

Zeroize the symmetric key in the unpacked IRM message once it has been copied into the crypt context, in both flow__irm_result_des and flow_rekey__irm_result_des, so key material does not linger in the protobuf buffer until it is freed. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Bound crc_check against short packets

2026-06-29T06:33:00+00:00

Reject a packet shorter than head_skip + CRCLEN before computing the CRC, instead of hashing over an underflowed length when the buffer is too small to hold the trailer. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

irmd: Complete bidirectional flow re-keying

2026-06-29T06:32:59+00:00

Extend re-key delivery beyond the locally-initiated watermark path: Handle peer-initiated re-key requests, allowing one request and one response per flow at a time. The client side wins if both ends try to re-key at the same time. Caches the peer certificate to support cert-less authenticated/signed re-keys. After a rekey, the initiator promotes first (timer) and starts sending under the new key. The responder observes the new key (peer_synced) and then the responder promotes. The responder will self-decide to use the new keys if it exhausted the older set in the case where it never sees the peer (unidirectional flow). Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Add constant-time comparison helper

2026-06-29T06:32:59+00:00

Add a function crypt_ct_cmp() that wraps CRYPTO_memcmp (OpenSSL) with a volatile-loop fallback, for comparing authentication tags without leaking timing. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Group sec_config authentication fields

2026-06-29T06:32:59+00:00

Nest the flat req_auth and cacert members of struct sec_config into a sub-struct a { req; cacert; }, keeping the authentication settings together. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Harden OpenSSL crypto backend

2026-06-29T06:32:59+00:00

This contains a few improvements and fixes in the OpenSSL backed. We now zeroize shared secrets with OPENSSL_clear_free. The i2d_PUBKEY output is bound against CRYPT_KEY_BUFSZ. We now return NULL rather than silently falling back to SHA-256 when a digest is unknown. FILE handles are now closed via pthread cleanup so a cancelled thread cannot leak them. The DHE kex tests now set the KDF NID explicitly, since the SHA-256 fallback is gone. Also refactors the PEM string loaders to clean up some code duplication. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Loop getrandom on short reads and EINTR

2026-06-29T06:32:59+00:00

The getrandom() function may return fewer bytes than requested or fail with EINTR. Loop until the buffer is filled, retrying on EINTR, instead of trusting a single call to fill the buffer completely. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Add MurmurHash3 hash_mix64 for hash tables

2026-06-29T06:32:59+00:00

Adds a (non-cryptographic) MurmurHash3 fmix64 finalizer for hashing an integer key to a table index, replacing the MD5-based bucket hashing in the pft. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

irmd: Deliver flow re-keying

2026-06-29T06:32:58+00:00

Re-key each encrypted flow's batch root periodically so a long-lived flow never exhausts or over-uses a single root. The IRMd re-runs the OAP exchange with the peer IRMd over the flow-update relay. The per-flow re-keying state is tracked in the registry (reg_flow). A re-key delivers one root seed from the OAP exchange. keyrot immediately HKDF-expands it into 128 node keys (KR_NODES_SZ = 128 × 32 B) and wipes the root. Then each of the 128 node keys is itself a root → HKDF-expanded into 64 (2^KEY_NODE_BITS) leaf keys, forked per direction; each leaf key is the actual AEAD key, good for 2^20 packets (the low counter bits are its nonce/seq). If the number of keys runs low, a re-key will be triggered (KEY_REKEY_WATERMARK). The rekey is signalled out of band to the application. The rbuff ACL is generalized into a flags word, so an RB_REKEY bit rides alongside the access RB_RD/RB_WR and FLOWDOWN/FLOWPEER bits. The RD and WR bits are revised ditching the fcntl historical weirdness. The seed is pulled via flow_read/flow_write, installed with crypt_rekey(). TX holds the old epoch until the peer is observed on the new one (or a grace deadline elapses), promoted from both the read and write paths so a recv-mostly flow still advances. Also fix the FLOW_ACCEPT and FLOW_ALLOC handlers, which on a key-buffer allocation failure returned from inside the cleanup-push region: that leaked the reply message and skipped both the stack-key scrub and the cleanup pop. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders