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-rw-r--r--src/lib/crypt/keyrot.c741
-rw-r--r--src/lib/crypt/keyrot.h74
-rw-r--r--src/lib/crypt/openssl.c504
-rw-r--r--src/lib/crypt/openssl.h42
4 files changed, 1077 insertions, 284 deletions
diff --git a/src/lib/crypt/keyrot.c b/src/lib/crypt/keyrot.c
new file mode 100644
index 00000000..8b0d9429
--- /dev/null
+++ b/src/lib/crypt/keyrot.c
@@ -0,0 +1,741 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2026
+ *
+ * Data-plane key-rotation schedule (node/leaf keys, selector)
+ *
+ * Dimitri Staessens <dimitri@ouroboros.rocks>
+ * Sander Vrijders <sander@ouroboros.rocks>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., http://www.fsf.org/about/contact/.
+ */
+
+#define _POSIX_C_SOURCE 200809L
+
+#include <config.h>
+
+#include <ouroboros/atomics.h>
+#include <ouroboros/crypt.h>
+#include <ouroboros/pthread.h>
+#include <ouroboros/rcu.h>
+
+#include "crypt/keyrot.h"
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+/*
+ * Per-flow keys are addressed by (epoch, node, leaf) and derived as:
+ * root = per-batch HKDF PRK from the OAP exchange, wiped once expanded
+ * nodes = HKDF-Expand(root, "o7s-keyrot-node") -> KEY_NODE_COUNT keys
+ * leaf = HKDF-Expand(node, "o7s-keyrot-leaf"|dir|leaf) -> AEAD key
+ * The epoch is a small wrapping counter, carried in the selector, that picks
+ * the live batch; a Tier-2 OAP re-key advances it. The "dir" byte forks the
+ * leaf keys per direction.
+ *
+ * Concurrency: cur/prev batch pointers are published by a re-key and read on
+ * the data path under an rcu_guard (lock-free RCU with liburcu, else a per-
+ * keyrot rwlock). The per-batch TX counter is atomic, so the (epoch, counter)
+ * nonce is unique without serialising TX. Leaf caches are THREAD-LOCAL (an app
+ * writer and the FRCT retransmit timer never share cache state), keyed on a
+ * global batch id and direct-mapped.
+ */
+
+#define KR_WITHIN_BITS (KEY_LEAF_BITS + KEY_NODE_BITS)
+#define KR_WITHIN_MASK (((uint64_t) 1 << KR_WITHIN_BITS) - 1)
+#define KR_N (KEY_NODE_COUNT)
+#define KR_LEAVES (1u << KEY_NODE_BITS)
+#define KR_BATCH_MAX ((uint64_t) KR_N << KR_WITHIN_BITS)
+#define KR_NODES_SZ ((size_t) KR_N * SYMMKEYSZ)
+#define KR_TCACHE_WAYS 16 /* per-thread cache slots per direction (pow2) */
+#define KR_EPOCHS 16 /* 4-bit wire epoch: gens before wrap */
+
+#define KR_RP_WORDS (KEY_REPLAY_WINDOW / 64) /* pow2; RFC 6479 bitmap */
+#define KR_RP_SHIFT 6
+#define KR_RP_MASK 63
+#define KR_RP_WINDOW (KEY_REPLAY_WINDOW - 64) /* reserve 1 slack word */
+
+static const char kr_node_label[] = "o7s-keyrot-node";
+static const char kr_leaf_label[] = "o7s-keyrot-leaf";
+
+struct kr_batch {
+ uint64_t id; /* process-global, unique; cache key (no ABA) */
+ uint8_t epoch; /* 4-bit wire selector */
+ uint8_t * nodes; /* KR_NODES_SZ in secure heap; NULL if empty */
+ uint64_t tx_ctr; /* atomic; per-batch so nonces never collide */
+
+ struct { /* RFC 6479-like anti-replay window */
+ uint64_t last; /* highest accepted ctr + 1 */
+ uint64_t bits[KR_RP_WORDS];
+ pthread_mutex_t mtx;
+ } rp;
+};
+
+struct kr_keycache {
+ uint8_t * key; /* SYMMKEYSZ, points into the per-thread slab */
+ uint64_t id; /* batch the cached key belongs to */
+ uint16_t node;
+ uint8_t leaf;
+ uint8_t dir;
+ bool valid;
+};
+
+struct keyrot {
+ struct kr_batch * cur; /* published; read on data path */
+ struct kr_batch * prev; /* NULL = none */
+ struct rcu_guard guard; /* re-key vs readers */
+ uint8_t role;
+ uint8_t tx_epoch; /* epoch TX currently stamps */
+ bool peer_switched; /* peer is on the cur epoch */
+};
+
+/* Per-thread leaf-key caches, freed by the thread-exit destructor. */
+struct kr_tcache {
+ struct kr_keycache tx[KR_TCACHE_WAYS];
+ struct kr_keycache rx[KR_TCACHE_WAYS];
+ uint8_t * slab; /* 2*KR_TCACHE_WAYS*SYMMKEYSZ secure heap */
+};
+
+static struct {
+ uint64_t next_id; /* batch-id allocator (atomic) */
+ pthread_key_t tcache_key; /* per-thread leaf-key caches */
+ pthread_once_t tcache_once;
+} kr_g = { 0, 0, PTHREAD_ONCE_INIT };
+
+static void kr_tcache_free(void * p)
+{
+ struct kr_tcache * t = p;
+
+ if (t == NULL)
+ return;
+
+ crypt_secure_free(t->slab, 2 * KR_TCACHE_WAYS * SYMMKEYSZ);
+ free(t);
+}
+
+static void kr_tcache_init(void)
+{
+ pthread_key_create(&kr_g.tcache_key, kr_tcache_free);
+}
+
+static struct kr_tcache * kr_tcache_get(void)
+{
+ struct kr_tcache * t;
+ size_t i;
+
+ pthread_once(&kr_g.tcache_once, kr_tcache_init);
+
+ t = pthread_getspecific(kr_g.tcache_key);
+ if (t != NULL)
+ return t;
+
+ t = malloc(sizeof(*t));
+ if (t == NULL)
+ goto fail_alloc;
+
+ memset(t, 0, sizeof(*t));
+
+ t->slab = crypt_secure_malloc(2 * KR_TCACHE_WAYS * SYMMKEYSZ);
+ if (t->slab == NULL)
+ goto fail_slab;
+
+ for (i = 0; i < KR_TCACHE_WAYS; i++) {
+ t->tx[i].key = t->slab + i * SYMMKEYSZ;
+ t->rx[i].key = t->slab + (KR_TCACHE_WAYS + i) * SYMMKEYSZ;
+ }
+
+ if (pthread_setspecific(kr_g.tcache_key, t) != 0)
+ goto fail_set;
+
+ return t;
+
+ fail_set:
+ crypt_secure_free(t->slab, 2 * KR_TCACHE_WAYS * SYMMKEYSZ);
+ fail_slab:
+ free(t);
+ fail_alloc:
+ return NULL;
+}
+
+static uint8_t * kr_expand_nodes(const uint8_t * root)
+{
+ uint8_t * nodes;
+ buffer_t prk;
+ buffer_t info;
+ buffer_t okm;
+
+ nodes = crypt_secure_malloc(KR_NODES_SZ);
+ if (nodes == NULL)
+ return NULL;
+
+ prk.len = SYMMKEYSZ;
+ prk.data = (uint8_t *) root;
+ info.len = sizeof(kr_node_label) - 1;
+ info.data = (uint8_t *) kr_node_label;
+ okm.len = KR_NODES_SZ;
+ okm.data = nodes;
+
+ if (crypt_hkdf_expand(prk, info, okm) != 0)
+ goto fail_expand;
+
+ return nodes;
+
+ fail_expand:
+ crypt_secure_free(nodes, KR_NODES_SZ);
+ return NULL;
+}
+
+static int kr_leaf_key(const uint8_t * node,
+ uint8_t leaf,
+ uint8_t dir,
+ uint8_t * out)
+{
+ uint8_t info_buf[sizeof(kr_leaf_label) - 1 + 2];
+ buffer_t prk;
+ buffer_t info;
+ buffer_t okm;
+ size_t n = sizeof(kr_leaf_label) - 1;
+
+ memcpy(info_buf, kr_leaf_label, n);
+ info_buf[n] = dir;
+ info_buf[n + 1] = leaf;
+
+ prk.len = SYMMKEYSZ;
+ prk.data = (uint8_t *) node;
+ info.len = n + 2;
+ info.data = info_buf;
+ okm.len = SYMMKEYSZ;
+ okm.data = out;
+
+ return crypt_hkdf_expand(prk, info, okm);
+}
+
+static __inline__ bool kr_kc_hit(const struct kr_keycache * kc,
+ const struct kr_batch * b,
+ uint16_t node,
+ uint8_t leaf,
+ uint8_t dir)
+{
+ if (!kc->valid)
+ return false;
+
+ if (kc->id != b->id)
+ return false;
+
+ if (kc->node != node)
+ return false;
+
+ if (kc->leaf != leaf)
+ return false;
+
+ return kc->dir == dir;
+}
+
+/* Fetch the leaf key; derive into the (direct-mapped) slot on a miss. */
+static const uint8_t * kr_kc_get(struct kr_keycache * cache,
+ const struct kr_batch * b,
+ uint16_t node,
+ uint8_t leaf,
+ uint8_t dir)
+{
+ struct kr_keycache * kc;
+ uint8_t * nkey;
+
+ kc = &cache[b->id & (KR_TCACHE_WAYS - 1)];
+
+ if (kr_kc_hit(kc, b, node, leaf, dir))
+ return kc->key;
+
+ nkey = b->nodes + (size_t) node * SYMMKEYSZ;
+ if (kr_leaf_key(nkey, leaf, dir, kc->key) != 0)
+ return NULL;
+
+ kc->valid = true;
+ kc->id = b->id;
+ kc->node = node;
+ kc->leaf = leaf;
+ kc->dir = dir;
+
+ return kc->key;
+}
+
+static void kr_sel_enc(uint8_t epoch,
+ uint16_t node,
+ uint32_t seq,
+ uint8_t sel[KR_SELECTOR_LEN])
+{
+ sel[0] = (uint8_t) ((epoch << 4) | ((node >> 8) & 0x0F));
+ sel[1] = (uint8_t) (node & 0xFF);
+ sel[2] = (uint8_t) (seq >> 24);
+ sel[3] = (uint8_t) (seq >> 16);
+ sel[4] = (uint8_t) (seq >> 8);
+ sel[5] = (uint8_t) (seq);
+}
+
+static void kr_sel_dec(const uint8_t sel[KR_SELECTOR_LEN],
+ uint8_t * epoch,
+ uint16_t * node,
+ uint32_t * seq)
+{
+ *epoch = (uint8_t) (sel[0] >> 4);
+ *node = (uint16_t) (((sel[0] & 0x0F) << 8) | sel[1]);
+ *seq = ((uint32_t) sel[2] << 24) | ((uint32_t) sel[3] << 16) |
+ ((uint32_t) sel[4] << 8) | (uint32_t) sel[5];
+}
+
+static uint64_t kr_ctr(uint16_t node,
+ uint32_t seq)
+{
+ return ((uint64_t) node << KR_WITHIN_BITS) |
+ ((uint64_t) seq & KR_WITHIN_MASK);
+}
+
+static void kr_nonce(uint64_t ctr,
+ uint8_t * nonce)
+{
+ size_t i;
+
+ memset(nonce, 0, KR_NONCE_LEN);
+
+ /* ctr big-endian in the low 8 bytes; high bytes stay zero */
+ for (i = 0; i < 8; i++)
+ nonce[i] = (uint8_t) (ctr >> (56 - 8 * i));
+}
+
+static struct kr_batch * kr_batch_create(uint8_t epoch,
+ const uint8_t * root)
+{
+ struct kr_batch * b;
+
+ b = malloc(sizeof(*b));
+ if (b == NULL)
+ goto fail_alloc;
+
+ b->nodes = kr_expand_nodes(root);
+ if (b->nodes == NULL)
+ goto fail_nodes;
+
+ b->id = FETCH_ADD_RELAXED(&kr_g.next_id, 1);
+ b->epoch = epoch;
+ b->tx_ctr = 0;
+ if (pthread_mutex_init(&b->rp.mtx, NULL) != 0)
+ goto fail_lock;
+
+ b->rp.last = 0;
+ memset(b->rp.bits, 0, sizeof(b->rp.bits));
+
+ return b;
+
+ fail_lock:
+ crypt_secure_free(b->nodes, KR_NODES_SZ);
+ free(b);
+ return NULL;
+ fail_nodes:
+ free(b);
+ fail_alloc:
+ return NULL;
+}
+
+static void kr_batch_free(struct kr_batch * b)
+{
+ if (b == NULL)
+ return;
+
+ pthread_mutex_destroy(&b->rp.mtx);
+ crypt_secure_free(b->nodes, KR_NODES_SZ);
+ free(b);
+}
+
+/*
+ * RFC 6479 anti-replay window keyed on the per-batch counter, with
+ * seq = ctr + 1 so 0 means "nothing accepted yet". Returns 0 if the
+ * packet is fresh (and records it), -1 on a replay or a too-old ctr.
+ */
+static int kr_rp_commit(struct kr_batch * b,
+ uint64_t ctr)
+{
+ uint64_t seq;
+ uint64_t idx;
+ uint64_t cur;
+ uint64_t diff;
+
+ seq = ctr + 1;
+
+ pthread_mutex_lock(&b->rp.mtx);
+
+ if (seq > b->rp.last) {
+ idx = seq >> KR_RP_SHIFT;
+ cur = b->rp.last >> KR_RP_SHIFT;
+ diff = idx - cur;
+ if (diff > KR_RP_WORDS)
+ diff = KR_RP_WORDS;
+
+ while (diff-- > 0) {
+ cur++;
+ b->rp.bits[cur & (KR_RP_WORDS - 1)] = 0;
+ }
+
+ b->rp.bits[idx & (KR_RP_WORDS - 1)] |=
+ (uint64_t) 1 << (seq & KR_RP_MASK);
+ b->rp.last = seq;
+ goto finish;
+ }
+
+ if (b->rp.last - seq >= KR_RP_WINDOW)
+ goto fail;
+
+ idx = seq >> KR_RP_SHIFT;
+ if (b->rp.bits[idx & (KR_RP_WORDS - 1)]
+ & ((uint64_t) 1 << (seq & KR_RP_MASK)))
+ goto fail;
+
+ b->rp.bits[idx & (KR_RP_WORDS - 1)] |=
+ (uint64_t) 1 << (seq & KR_RP_MASK);
+ finish:
+ pthread_mutex_unlock(&b->rp.mtx);
+
+ return 0;
+ fail:
+ pthread_mutex_unlock(&b->rp.mtx);
+
+ return -1;
+}
+
+struct keyrot * keyrot_create(const uint8_t * root,
+ uint8_t epoch,
+ uint8_t role)
+{
+ struct keyrot * kr;
+
+ assert(root != NULL);
+ assert(role <= 1);
+
+ if (epoch >= KR_EPOCHS)
+ goto fail_kr;
+
+ kr = malloc(sizeof(*kr));
+ if (kr == NULL)
+ goto fail_kr;
+
+ memset(kr, 0, sizeof(*kr));
+
+ kr->role = role;
+ kr->tx_epoch = epoch;
+ kr->peer_switched = true;
+ kr->prev = NULL;
+
+ kr->cur = kr_batch_create(epoch, root);
+ if (kr->cur == NULL)
+ goto fail_cur;
+
+ if (rcu_guard_init(&kr->guard))
+ goto fail_guard;
+
+ return kr;
+
+ fail_guard:
+ kr_batch_free(kr->cur);
+ fail_cur:
+ free(kr);
+ fail_kr:
+ return NULL;
+}
+
+void keyrot_destroy(struct keyrot * kr)
+{
+ if (kr == NULL)
+ return;
+
+ /* Wait out any in-flight reader before freeing batches. */
+ rcu_drain(&kr->guard);
+
+ kr_batch_free(kr->cur);
+ kr_batch_free(kr->prev);
+
+ rcu_guard_fini(&kr->guard);
+
+ free(kr);
+}
+
+int keyrot_rekey(struct keyrot * kr,
+ const uint8_t * root,
+ uint8_t epoch)
+{
+ struct kr_batch * nb;
+ struct kr_batch * old_prev;
+
+ assert(kr != NULL);
+ assert(root != NULL);
+
+ if (epoch >= KR_EPOCHS)
+ return -1;
+
+ nb = kr_batch_create(epoch, root);
+ if (nb == NULL)
+ return -1;
+
+ rcu_wrlock(&kr->guard);
+
+ old_prev = kr->prev;
+ rcu_assign(kr->prev, kr->cur);
+ rcu_publish(nb);
+ rcu_assign(kr->cur, nb);
+
+ /* TX keeps the old epoch until the peer is seen on the new one. */
+ STORE_RELEASE(&kr->peer_switched, false);
+
+ rcu_wrunlock(&kr->guard);
+
+ /* old_prev is unreachable now; reclaim past any live reader. */
+ rcu_reclaim(&kr->guard);
+ kr_batch_free(old_prev);
+
+ return 0;
+}
+
+void keyrot_tx_promote(struct keyrot * kr)
+{
+ assert(kr != NULL);
+
+ /* Serialise with keyrot_rekey so tx_epoch tracks a consistent cur. */
+ rcu_wrlock(&kr->guard);
+ STORE_RELAXED(&kr->tx_epoch, rcu_deref(kr->cur)->epoch);
+ rcu_wrunlock(&kr->guard);
+}
+
+int keyrot_tx_next(struct keyrot * kr,
+ uint8_t sel[KR_SELECTOR_LEN],
+ const uint8_t ** key,
+ uint8_t nonce[KR_NONCE_LEN])
+{
+ struct kr_tcache * tc;
+ struct kr_batch * cur;
+ struct kr_batch * prev;
+ struct kr_batch * b;
+ uint64_t ctr;
+ uint16_t node;
+ uint8_t leaf;
+ uint8_t txe;
+ uint8_t epoch;
+ uint32_t seq;
+ const uint8_t * k;
+
+ assert(kr != NULL);
+ assert(key != NULL);
+
+ tc = kr_tcache_get();
+ if (tc == NULL)
+ return -1;
+
+ rcu_rdlock(&kr->guard);
+
+ cur = rcu_deref(kr->cur);
+ prev = rcu_deref(kr->prev);
+ rcu_consume(cur);
+ rcu_consume(prev);
+ txe = LOAD_RELAXED(&kr->tx_epoch);
+
+ if (cur->epoch == txe)
+ b = cur;
+ else if (prev != NULL && prev->epoch == txe)
+ b = prev;
+ else
+ b = NULL;
+
+ if (b == NULL) {
+ rcu_rdunlock(&kr->guard);
+ return -1; /* tx_epoch batch gone; next promote resyncs */
+ }
+
+ /* Slot reserved even if exhausted; tx_nodes_left clamps the count. */
+ ctr = FETCH_ADD_RELAXED(&b->tx_ctr, 1);
+ if (ctr >= KR_BATCH_MAX) {
+ rcu_rdunlock(&kr->guard);
+ return -1; /* batch exhausted */
+ }
+
+ node = (uint16_t) (ctr >> KR_WITHIN_BITS);
+ leaf = (uint8_t) ((ctr >> KEY_LEAF_BITS) & (KR_LEAVES - 1));
+ seq = (uint32_t) (ctr & KR_WITHIN_MASK);
+ epoch = b->epoch;
+
+ k = kr_kc_get(tc->tx, b, node, leaf, kr->role);
+
+ rcu_rdunlock(&kr->guard);
+
+ if (k == NULL)
+ return -1;
+
+ kr_sel_enc(epoch, node, seq, sel);
+ kr_nonce(ctr, nonce);
+
+ *key = k;
+
+ return 0;
+}
+
+int keyrot_rx_lookup(struct keyrot * kr,
+ const uint8_t sel[KR_SELECTOR_LEN],
+ const uint8_t ** key,
+ uint8_t nonce[KR_NONCE_LEN],
+ struct kr_rx * rx)
+{
+ struct kr_tcache * tc;
+ struct kr_batch * cur;
+ struct kr_batch * prev;
+ struct kr_batch * b;
+ uint8_t epoch;
+ uint16_t node;
+ uint32_t seq;
+ uint64_t ctr;
+ uint8_t leaf;
+ const uint8_t * k;
+
+ assert(kr != NULL);
+ assert(key != NULL);
+
+ kr_sel_dec(sel, &epoch, &node, &seq);
+
+ if (node >= KR_N)
+ return -1;
+
+ tc = kr_tcache_get();
+ if (tc == NULL)
+ return -1;
+
+ rcu_rdlock(&kr->guard);
+
+ cur = rcu_deref(kr->cur);
+ prev = rcu_deref(kr->prev);
+ rcu_consume(cur);
+ rcu_consume(prev);
+
+ if (epoch == cur->epoch) {
+ b = cur;
+ } else if (prev != NULL && epoch == prev->epoch) {
+ b = prev;
+ } else {
+ rcu_rdunlock(&kr->guard);
+ return -1; /* unknown epoch */
+ }
+
+ ctr = kr_ctr(node, seq);
+ leaf = (uint8_t) ((ctr >> KEY_LEAF_BITS) & (KR_LEAVES - 1));
+
+ /* peer's tx direction */
+ k = kr_kc_get(tc->rx, b, node, leaf, (uint8_t) (kr->role ^ 1));
+
+ rx->id = b->id;
+ rx->ctr = ctr;
+
+ rcu_rdunlock(&kr->guard);
+
+ if (k == NULL)
+ return -1;
+
+ kr_nonce(ctr, nonce);
+
+ *key = k;
+
+ return 0;
+}
+
+/*
+ * Commit a packet that authenticated under the batch keyrot_rx_lookup
+ * selected. Re-finds that batch by id (epoch may have advanced) and,
+ * if still resident, advances the replay window and records that the
+ * peer is on the current batch. Runs only post-AEAD so a forged or
+ * replayed packet can mutate no receiver state. Returns -1 on replay.
+ */
+int keyrot_rx_commit(struct keyrot * kr,
+ const struct kr_rx * rx)
+{
+ struct kr_batch * cur;
+ struct kr_batch * prev;
+ struct kr_batch * b;
+ int rc;
+
+ assert(kr != NULL);
+ assert(rx != NULL);
+
+ rcu_rdlock(&kr->guard);
+
+ cur = rcu_deref(kr->cur);
+ prev = rcu_deref(kr->prev);
+ rcu_consume(cur);
+ rcu_consume(prev);
+
+ if (cur->id == rx->id)
+ b = cur;
+ else if (prev != NULL && prev->id == rx->id)
+ b = prev;
+ else
+ b = NULL;
+
+ if (b == NULL) {
+ rcu_rdunlock(&kr->guard);
+ return 0; /* batch evicted post-auth; nothing to protect */
+ }
+
+ rc = kr_rp_commit(b, rx->ctr);
+ if (rc == 0 && b == cur)
+ STORE_RELEASE(&kr->peer_switched, true);
+
+ rcu_rdunlock(&kr->guard);
+
+ return rc;
+}
+
+bool keyrot_peer_switched(const struct keyrot * kr)
+{
+ assert(kr != NULL);
+
+ return LOAD_ACQUIRE(&kr->peer_switched);
+}
+
+unsigned keyrot_tx_nodes_left(struct keyrot * kr)
+{
+ struct kr_batch * cur;
+ struct kr_batch * prev;
+ struct kr_batch * b;
+ uint64_t ctr;
+ unsigned used;
+ uint8_t txe;
+
+ assert(kr != NULL);
+
+ rcu_rdlock(&kr->guard);
+ cur = rcu_deref(kr->cur);
+ prev = rcu_deref(kr->prev);
+ rcu_consume(cur);
+ rcu_consume(prev);
+ txe = LOAD_RELAXED(&kr->tx_epoch);
+
+ if (cur->epoch == txe)
+ b = cur;
+ else if (prev != NULL && prev->epoch == txe)
+ b = prev;
+ else
+ b = NULL;
+
+ ctr = b != NULL ? LOAD_RELAXED(&b->tx_ctr) : KR_BATCH_MAX;
+ rcu_rdunlock(&kr->guard);
+
+ used = (unsigned) (ctr >> KR_WITHIN_BITS);
+ if (used >= KR_N)
+ return 0;
+
+ return KR_N - used;
+}
diff --git a/src/lib/crypt/keyrot.h b/src/lib/crypt/keyrot.h
new file mode 100644
index 00000000..6a598f76
--- /dev/null
+++ b/src/lib/crypt/keyrot.h
@@ -0,0 +1,74 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2026
+ *
+ * Data-plane key-rotation schedule (node/leaf keys, selector)
+ *
+ * Dimitri Staessens <dimitri@ouroboros.rocks>
+ * Sander Vrijders <sander@ouroboros.rocks>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., http://www.fsf.org/about/contact/.
+ */
+
+#ifndef OUROBOROS_LIB_CRYPT_KEYROT_H
+#define OUROBOROS_LIB_CRYPT_KEYROT_H
+
+#include <ouroboros/crypt.h> /* SYMMKEYSZ, NONCESZ */
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#define KR_SELECTOR_LEN 6
+#define KR_NONCE_LEN NONCESZ
+
+struct keyrot;
+
+struct kr_rx {
+ uint64_t id; /* batch id of the matched epoch */
+ uint64_t ctr; /* packet counter for replay check */
+};
+
+struct keyrot * keyrot_create(const uint8_t * root,
+ uint8_t epoch,
+ uint8_t role);
+
+void keyrot_destroy(struct keyrot * kr);
+
+int keyrot_rekey(struct keyrot * kr,
+ const uint8_t * root,
+ uint8_t epoch);
+
+/* Promote TX to the installed (new) batch once the peer is on it. */
+void keyrot_tx_promote(struct keyrot * kr);
+
+int keyrot_tx_next(struct keyrot * kr,
+ uint8_t sel[KR_SELECTOR_LEN],
+ const uint8_t ** key,
+ uint8_t nonce[KR_NONCE_LEN]);
+
+int keyrot_rx_lookup(struct keyrot * kr,
+ const uint8_t sel[KR_SELECTOR_LEN],
+ const uint8_t ** key,
+ uint8_t nonce[KR_NONCE_LEN],
+ struct kr_rx * rx);
+
+/* Commit an authenticated packet: replay window + peer-switched. */
+int keyrot_rx_commit(struct keyrot * kr,
+ const struct kr_rx * rx);
+
+/* True once an RX packet under the current batch has been observed. */
+bool keyrot_peer_switched(const struct keyrot * kr);
+
+unsigned keyrot_tx_nodes_left(struct keyrot * kr);
+
+#endif /* OUROBOROS_LIB_CRYPT_KEYROT_H */
diff --git a/src/lib/crypt/openssl.c b/src/lib/crypt/openssl.c
index d4ffc00b..7a4abec9 100644
--- a/src/lib/crypt/openssl.c
+++ b/src/lib/crypt/openssl.c
@@ -53,27 +53,14 @@
#define HKDF_INFO_DHE "o7s-ossl-dhe"
#define HKDF_INFO_ENCAP "o7s-ossl-encap"
-#define HKDF_INFO_ROTATION "o7s-key-rotation"
#define HKDF_SALT_LEN 32 /* SHA-256 output size */
+#define AEAD_NONCE_LEN 12 /* 96-bit deterministic IV (SP 800-38D) */
+#define AEAD_TAG_LEN 16 /* 128-bit AEAD authentication tag */
struct ossl_crypt_ctx {
EVP_CIPHER_CTX * evp_ctx;
const EVP_CIPHER * cipher;
- int ivsz;
int tagsz;
-
- struct {
- uint8_t * cur; /* current key */
- uint8_t * prv; /* rotated key */
- } keys;
-
- struct {
- uint32_t cntr; /* counter */
- uint32_t mask; /* phase mask */
- uint32_t age; /* counter within epoch */
- uint8_t phase; /* current key phase */
- uint8_t salt[HKDF_SALT_LEN];
- } rot; /* rotation logic */
};
struct kdf_info {
@@ -84,17 +71,6 @@ struct kdf_info {
buffer_t key;
};
-/* Key rotation macros */
-#define HAS_PHASE_BIT_TOGGLED(ctx) \
- (((ctx)->rot.cntr & (ctx)->rot.mask) != \
- (((ctx)->rot.cntr - 1) & (ctx)->rot.mask))
-
-#define HAS_GRACE_EXPIRED(ctx) \
- ((ctx)->rot.age >= ((ctx)->rot.mask >> 1))
-
-#define ROTATION_TOO_RECENT(ctx) \
- ((ctx)->rot.age < ((ctx)->rot.mask - ((ctx)->rot.mask >> 2)))
-
/* Convert hash NID to OpenSSL digest name string for HKDF */
static const char * hash_nid_to_digest_name(int nid)
{
@@ -145,21 +121,20 @@ static int get_pk_bytes_from_key(EVP_PKEY * key,
}
/* Derive salt from public key bytes by hashing them */
-static int derive_salt_from_pk_bytes(buffer_t pk,
- uint8_t * salt,
- size_t salt_len)
+static int derive_salt_from_pk_bytes(buffer_t pk,
+ buffer_t salt)
{
uint8_t hash[EVP_MAX_MD_SIZE];
unsigned hash_len;
assert(pk.data != NULL);
- assert(salt != NULL);
+ assert(salt.data != NULL);
if (EVP_Digest(pk.data, pk.len, hash, &hash_len,
EVP_sha256(), NULL) != 1)
goto fail_digest;
- memcpy(salt, hash, salt_len < hash_len ? salt_len : hash_len);
+ memcpy(salt.data, hash, salt.len < hash_len ? salt.len : hash_len);
return 0;
fail_digest:
@@ -167,10 +142,9 @@ static int derive_salt_from_pk_bytes(buffer_t pk,
}
/* Derive salt from two public key byte buffers (DHE) in canonical order */
-static int derive_salt_from_pk_bytes_dhe(buffer_t local,
- buffer_t remote,
- uint8_t * salt,
- size_t salt_len)
+static int derive_salt_from_pk_bytes_dhe(buffer_t local,
+ buffer_t remote,
+ buffer_t salt)
{
uint8_t * concat;
size_t concat_len;
@@ -181,7 +155,7 @@ static int derive_salt_from_pk_bytes_dhe(buffer_t local,
assert(local.data != NULL);
assert(remote.data != NULL);
- assert(salt != NULL);
+ assert(salt.data != NULL);
concat_len = local.len + remote.len;
concat = OPENSSL_malloc(concat_len);
@@ -205,7 +179,7 @@ static int derive_salt_from_pk_bytes_dhe(buffer_t local,
OPENSSL_free(concat);
- memcpy(salt, hash, salt_len < hash_len ? salt_len : hash_len);
+ memcpy(salt.data, hash, salt.len < hash_len ? salt.len : hash_len);
return 0;
fail_digest:
@@ -259,117 +233,144 @@ static int derive_key_hkdf(struct kdf_info * ki)
return -ECRYPT;
}
-/* Key rotation helper functions implementation */
-static int should_rotate_key_rx(struct ossl_crypt_ctx * ctx,
- uint8_t rx_phase)
+int openssl_hkdf_expand(buffer_t key,
+ buffer_t info,
+ buffer_t out)
{
- assert(ctx != NULL);
+ EVP_KDF * kdf;
+ EVP_KDF_CTX * kctx;
+ OSSL_PARAM params[5];
+ int mode = EVP_KDF_HKDF_MODE_EXPAND_ONLY;
+ int idx = 0;
+ int ret = -1;
+
+ kdf = EVP_KDF_fetch(NULL, "HKDF", NULL);
+ if (kdf == NULL)
+ goto fail_fetch;
- /* Phase must have changed */
- if (rx_phase == ctx->rot.phase)
- return 0;
+ kctx = EVP_KDF_CTX_new(kdf);
+ if (kctx == NULL)
+ goto fail_ctx;
+
+ params[idx++] = OSSL_PARAM_construct_utf8_string(
+ "digest", (char *) "SHA256", 0);
+ params[idx++] = OSSL_PARAM_construct_int("mode", &mode);
+ params[idx++] = OSSL_PARAM_construct_octet_string(
+ "key", key.data, key.len);
+ params[idx++] = OSSL_PARAM_construct_octet_string(
+ "info", info.data, info.len);
+ params[idx] = OSSL_PARAM_construct_end();
- if (ROTATION_TOO_RECENT(ctx))
- return 0;
+ if (EVP_KDF_derive(kctx, out.data, out.len, params) == 1)
+ ret = 0;
- return 1;
+ EVP_KDF_CTX_free(kctx);
+ fail_ctx:
+ EVP_KDF_free(kdf);
+ fail_fetch:
+ return ret;
}
-static int rotate_key(struct ossl_crypt_ctx * ctx)
+/* AEAD seal: encrypt in with key/nonce, bind aad, append tag */
+int openssl_seal(struct ossl_crypt_ctx * ctx,
+ const uint8_t * key,
+ const uint8_t * nonce,
+ buffer_t aad,
+ buffer_t in,
+ uint8_t * out,
+ uint8_t * tag)
{
- struct kdf_info ki;
- uint8_t * tmp;
+ int out_sz;
+ int tmp_sz;
assert(ctx != NULL);
+ assert(ctx->tagsz > 0); /* AEAD mandated at ctx creation */
- /* Swap keys - move current to prev */
- tmp = ctx->keys.prv;
- ctx->keys.prv = ctx->keys.cur;
+ EVP_CIPHER_CTX_reset(ctx->evp_ctx);
- if (tmp != NULL) {
- /* Reuse old prev_key memory for new key */
- ctx->keys.cur = tmp;
- } else {
- /* First rotation - allocate new memory */
- ctx->keys.cur = OPENSSL_secure_malloc(SYMMKEYSZ);
- if (ctx->keys.cur == NULL)
- return -ECRYPT;
- }
+ if (EVP_EncryptInit_ex(ctx->evp_ctx, ctx->cipher, NULL,
+ NULL, NULL) != 1)
+ return -1;
- /* Derive new key from previous key using HKDF */
- ki.secret.data = ctx->keys.prv;
- ki.secret.len = SYMMKEYSZ;
- ki.nid = NID_sha256;
- ki.salt.data = ctx->rot.salt;
- ki.salt.len = HKDF_SALT_LEN;
- ki.info.data = (uint8_t *) HKDF_INFO_ROTATION;
- ki.info.len = strlen(HKDF_INFO_ROTATION);
- ki.key.data = ctx->keys.cur;
- ki.key.len = SYMMKEYSZ;
+ /* Pin the AEAD nonce to 96 bits (SP 800-38D deterministic IV). */
+ if (EVP_CIPHER_CTX_ctrl(ctx->evp_ctx, EVP_CTRL_AEAD_SET_IVLEN,
+ AEAD_NONCE_LEN, NULL) != 1)
+ return -1;
- if (derive_key_hkdf(&ki) != 0)
- return -ECRYPT;
+ if (EVP_EncryptInit_ex(ctx->evp_ctx, NULL, NULL,
+ key, nonce) != 1)
+ return -1;
- ctx->rot.age = 0;
- ctx->rot.phase = !ctx->rot.phase;
+ if (EVP_EncryptUpdate(ctx->evp_ctx, NULL, &tmp_sz,
+ aad.data, (int) aad.len) != 1)
+ return -1;
- return 0;
-}
+ if (EVP_EncryptUpdate(ctx->evp_ctx, out, &out_sz,
+ in.data, (int) in.len) != 1)
+ return -1;
-static void cleanup_old_key(struct ossl_crypt_ctx * ctx)
-{
- assert(ctx != NULL);
+ if (EVP_EncryptFinal_ex(ctx->evp_ctx, out + out_sz, &tmp_sz) != 1)
+ return -1;
- if (ctx->keys.prv == NULL)
- return;
+ out_sz += tmp_sz;
- if (!HAS_GRACE_EXPIRED(ctx))
- return;
+ if (EVP_CIPHER_CTX_ctrl(ctx->evp_ctx, EVP_CTRL_AEAD_GET_TAG,
+ ctx->tagsz, tag) != 1)
+ return -1;
- OPENSSL_secure_clear_free(ctx->keys.prv, SYMMKEYSZ);
- ctx->keys.prv = NULL;
+ return out_sz;
}
-static int try_decrypt(struct ossl_crypt_ctx * ctx,
- uint8_t * key,
- uint8_t * iv,
- uint8_t * input,
- int in_sz,
- uint8_t * out,
- int * out_sz)
+/* AEAD open: decrypt in with key/nonce, verify aad and tag */
+int openssl_open(struct ossl_crypt_ctx * ctx,
+ const uint8_t * key,
+ const uint8_t * nonce,
+ buffer_t aad,
+ buffer_t in,
+ const uint8_t * tag,
+ buffer_t * out)
{
- uint8_t * tag;
- int tmp_sz;
- int ret;
+ int out_sz;
+ int tmp_sz;
- tag = input + in_sz;
+ assert(ctx != NULL);
+ assert(ctx->tagsz > 0); /* AEAD mandated at ctx creation */
EVP_CIPHER_CTX_reset(ctx->evp_ctx);
- ret = EVP_DecryptInit_ex(ctx->evp_ctx, ctx->cipher, NULL, key, iv);
- if (ret != 1)
+ if (EVP_DecryptInit_ex(ctx->evp_ctx, ctx->cipher, NULL,
+ NULL, NULL) != 1)
return -1;
- if (ctx->tagsz > 0) {
- ret = EVP_CIPHER_CTX_ctrl(ctx->evp_ctx, EVP_CTRL_AEAD_SET_TAG,
- ctx->tagsz, tag);
- if (ret != 1)
- return -1;
- }
+ /* Pin the AEAD nonce to 96 bits (SP 800-38D deterministic IV). */
+ if (EVP_CIPHER_CTX_ctrl(ctx->evp_ctx, EVP_CTRL_AEAD_SET_IVLEN,
+ AEAD_NONCE_LEN, NULL) != 1)
+ return -1;
- ret = EVP_DecryptUpdate(ctx->evp_ctx, out, &tmp_sz, input, in_sz);
- if (ret != 1)
+ if (EVP_DecryptInit_ex(ctx->evp_ctx, NULL, NULL, key, nonce) != 1)
return -1;
- *out_sz = tmp_sz;
+ if (EVP_CIPHER_CTX_ctrl(ctx->evp_ctx, EVP_CTRL_AEAD_SET_TAG,
+ ctx->tagsz, (void *) tag) != 1)
+ return -1;
- ret = EVP_DecryptFinal_ex(ctx->evp_ctx, out + tmp_sz, &tmp_sz);
- if (ret != 1)
+ if (EVP_DecryptUpdate(ctx->evp_ctx, NULL, &tmp_sz,
+ aad.data, (int) aad.len) != 1)
return -1;
- *out_sz += tmp_sz;
+ if (EVP_DecryptUpdate(ctx->evp_ctx, out->data, &out_sz,
+ in.data, (int) in.len) != 1)
+ return -1;
- return 0;
+ if (EVP_DecryptFinal_ex(ctx->evp_ctx, out->data + out_sz,
+ &tmp_sz) != 1)
+ return -1;
+
+ out_sz += tmp_sz;
+
+ out->len = (size_t) out_sz;
+
+ return out_sz;
}
/*
@@ -397,11 +398,14 @@ static int __openssl_dhe_derive(EVP_PKEY * pkp,
ret = i2d_PUBKEY(pkp, &local_pk.data);
if (ret <= 0)
goto fail_local;
+
local_pk.len = (size_t) ret;
+ ki.salt.len = HKDF_SALT_LEN;
+ ki.salt.data = salt_buf;
+
/* Derive salt from both public keys */
- if (derive_salt_from_pk_bytes_dhe(local_pk, remote_pk, salt_buf,
- HKDF_SALT_LEN) < 0)
+ if (derive_salt_from_pk_bytes_dhe(local_pk, remote_pk, ki.salt) < 0)
goto fail_salt;
ctx = EVP_PKEY_CTX_new(pkp, NULL);
@@ -438,8 +442,6 @@ static int __openssl_dhe_derive(EVP_PKEY * pkp,
ki.info.data = (uint8_t *) HKDF_INFO_DHE;
ki.key.len = SYMMKEYSZ;
ki.key.data = s;
- ki.salt.len = HKDF_SALT_LEN;
- ki.salt.data = salt_buf;
/* Derive symmetric key from shared secret using HKDF */
ret = derive_key_hkdf(&ki);
@@ -718,13 +720,17 @@ ssize_t openssl_kem_encap(buffer_t pk,
EVP_PKEY * pub;
uint8_t * pos;
uint8_t salt[HKDF_SALT_LEN];
+ buffer_t salt_b;
ssize_t ret;
assert(pk.data != NULL);
assert(ct != NULL);
assert(s != NULL);
- if (derive_salt_from_pk_bytes(pk, salt, HKDF_SALT_LEN) < 0)
+ salt_b.len = HKDF_SALT_LEN;
+ salt_b.data = salt;
+
+ if (derive_salt_from_pk_bytes(pk, salt_b) < 0)
goto fail_salt;
pos = pk.data;
@@ -750,13 +756,17 @@ ssize_t openssl_kem_encap_raw(buffer_t pk,
EVP_PKEY * pub;
const char * algo;
uint8_t salt[HKDF_SALT_LEN];
+ buffer_t salt_b;
ssize_t ret;
assert(pk.data != NULL);
assert(ct != NULL);
assert(s != NULL);
- if (derive_salt_from_pk_bytes(pk, salt, HKDF_SALT_LEN) < 0)
+ salt_b.len = HKDF_SALT_LEN;
+ salt_b.data = salt;
+
+ if (derive_salt_from_pk_bytes(pk, salt_b) < 0)
goto fail_salt;
algo = __openssl_hybrid_algo_from_len(pk.len);
@@ -790,12 +800,16 @@ int openssl_kem_decap(EVP_PKEY * priv,
size_t secret_len;
int ret;
uint8_t salt[HKDF_SALT_LEN];
+ buffer_t salt_b;
/* Extract public key bytes from private key */
if (get_pk_bytes_from_key(priv, &pk) < 0)
goto fail_pk;
- if (derive_salt_from_pk_bytes(pk, salt, HKDF_SALT_LEN) < 0)
+ salt_b.len = HKDF_SALT_LEN;
+ salt_b.data = salt;
+
+ if (derive_salt_from_pk_bytes(pk, salt_b) < 0)
goto fail_salt;
ctx = EVP_PKEY_CTX_new(priv, NULL);
@@ -858,13 +872,14 @@ void openssl_pkp_destroy(EVP_PKEY * pkp)
EVP_PKEY_free(pkp);
}
-int __openssl_get_curve(EVP_PKEY * pub,
- char * algo)
+static int openssl_get_curve(EVP_PKEY * pub,
+ char * algo)
{
int ret;
size_t len = KEX_ALGO_BUFSZ;
ret = EVP_PKEY_get_utf8_string_param(pub, "group", algo, len, &len);
+
return ret == 1 ? 0 : -ECRYPT;
}
@@ -889,9 +904,10 @@ int openssl_get_algo_from_pk_der(buffer_t pk,
strcpy(algo, type_str);
- if ((IS_EC_GROUP(algo) || IS_DH_GROUP(algo)) &&
- __openssl_get_curve(pub, algo) < 0)
- goto fail_pub;
+ if (IS_EC_GROUP(algo) || IS_DH_GROUP(algo)) {
+ if (openssl_get_curve(pub, algo) < 0)
+ goto fail_pub;
+ }
EVP_PKEY_free(pub);
return 0;
@@ -949,141 +965,122 @@ int openssl_dhe_derive(EVP_PKEY * pkp,
return -ECRYPT;
}
-int openssl_encrypt(struct ossl_crypt_ctx * ctx,
- buffer_t in,
- buffer_t * out)
+/* Set up a fresh AEAD cipher ctx for nid: reject non-AEAD / oversized IV. */
+static int ossl_cipher_ctx_init(struct ossl_crypt_ctx * ctx,
+ int nid)
{
- uint8_t * ptr;
- uint8_t * iv;
- int in_sz;
- int out_sz;
- int tmp_sz;
- int ret;
-
- assert(ctx != NULL);
-
- in_sz = (int) in.len;
-
- out->data = malloc(in.len + EVP_MAX_BLOCK_LENGTH + \
- ctx->ivsz + ctx->tagsz);
- if (out->data == NULL)
- goto fail_malloc;
-
- iv = out->data;
- ptr = out->data + ctx->ivsz;
+ ctx->cipher = EVP_get_cipherbynid(nid);
+ if (ctx->cipher == NULL)
+ return -1;
- if (random_buffer(iv, ctx->ivsz) < 0)
- goto fail_encrypt;
+ /* IV must fit the NONCESZ nonce buffer. */
+ if (EVP_CIPHER_get_iv_length(ctx->cipher) > NONCESZ)
+ return -1;
- /* Set IV bit 7 to current key phase (KEY_ROTATION_BIT of counter) */
- if (ctx->rot.cntr & ctx->rot.mask)
- iv[0] |= 0x80;
- else
- iv[0] &= 0x7F;
+ /* Authenticated encryption is mandatory; reject non-AEAD ciphers. */
+ if ((EVP_CIPHER_flags(ctx->cipher) & EVP_CIPH_FLAG_AEAD_CIPHER) == 0)
+ return -1;
- EVP_CIPHER_CTX_reset(ctx->evp_ctx);
+ ctx->tagsz = AEAD_TAG_LEN;
- ret = EVP_EncryptInit_ex(ctx->evp_ctx, ctx->cipher, NULL,
- ctx->keys.cur, iv);
- if (ret != 1)
- goto fail_encrypt;
+ ctx->evp_ctx = EVP_CIPHER_CTX_new();
+ if (ctx->evp_ctx == NULL)
+ return -1;
- ret = EVP_EncryptUpdate(ctx->evp_ctx, ptr, &tmp_sz, in.data, in_sz);
- if (ret != 1)
- goto fail_encrypt;
+ return 0;
+}
- out_sz = tmp_sz;
- ret = EVP_EncryptFinal_ex(ctx->evp_ctx, ptr + tmp_sz, &tmp_sz);
- if (ret != 1)
- goto fail_encrypt;
+/* One-shot AEAD seal over an explicit key/nonce (no keyrot). out = ct ‖ tag. */
+int openssl_oneshot_seal(int nid,
+ const uint8_t * key,
+ const uint8_t * nonce,
+ buffer_t aad,
+ buffer_t in,
+ buffer_t * out)
+{
+ struct ossl_crypt_ctx ctx;
+ int out_sz;
- out_sz += tmp_sz;
+ assert(key != NULL);
+ assert(nonce != NULL);
+ assert(out != NULL);
- /* For AEAD ciphers, get and append the authentication tag */
- if (ctx->tagsz > 0) {
- ret = EVP_CIPHER_CTX_ctrl(ctx->evp_ctx, EVP_CTRL_AEAD_GET_TAG,
- ctx->tagsz, ptr + out_sz);
- if (ret != 1)
- goto fail_encrypt;
- out_sz += ctx->tagsz;
- }
+ memset(&ctx, 0, sizeof(ctx));
- assert(out_sz >= in_sz);
+ if (ossl_cipher_ctx_init(&ctx, nid) < 0)
+ goto fail_cipher;
- out->len = (size_t) out_sz + ctx->ivsz;
+ out->data = malloc(in.len + EVP_MAX_BLOCK_LENGTH + ctx.tagsz);
+ if (out->data == NULL)
+ goto fail_ctx;
- /* Increment packet counter and check for key rotation */
- ctx->rot.cntr++;
- ctx->rot.age++;
+ out_sz = openssl_seal(&ctx, key, nonce, aad, in,
+ out->data, out->data + in.len);
+ if (out_sz < 0)
+ goto fail_seal;
- if (HAS_PHASE_BIT_TOGGLED(ctx)) {
- if (rotate_key(ctx) != 0)
- goto fail_encrypt;
- }
+ out->len = (size_t) out_sz + ctx.tagsz;
- cleanup_old_key(ctx);
+ EVP_CIPHER_CTX_free(ctx.evp_ctx);
return 0;
- fail_encrypt:
+
+ fail_seal:
free(out->data);
- fail_malloc:
+ fail_ctx:
+ EVP_CIPHER_CTX_free(ctx.evp_ctx);
+ fail_cipher:
clrbuf(*out);
return -ECRYPT;
}
-int openssl_decrypt(struct ossl_crypt_ctx * ctx,
- buffer_t in,
- buffer_t * out)
+/* One-shot AEAD open; in = ct ‖ tag, verifies aad and tag. */
+int openssl_oneshot_open(int nid,
+ const uint8_t * key,
+ const uint8_t * nonce,
+ buffer_t aad,
+ buffer_t in,
+ buffer_t * out)
{
- uint8_t * iv;
- uint8_t * input;
- uint8_t rx_phase;
- int out_sz;
- int in_sz;
-
- assert(ctx != NULL);
-
- in_sz = (int) in.len - ctx->ivsz;
- if (in_sz < ctx->tagsz)
- return -ECRYPT;
+ struct ossl_crypt_ctx ctx;
+ buffer_t ct;
+ const uint8_t * tag;
+ int in_sz;
- in_sz -= ctx->tagsz;
+ assert(key != NULL);
+ assert(nonce != NULL);
+ assert(out != NULL);
- out->data = malloc(in_sz + EVP_MAX_BLOCK_LENGTH);
- if (out->data == NULL)
- goto fail_malloc;
+ memset(&ctx, 0, sizeof(ctx));
- iv = in.data;
- input = in.data + ctx->ivsz;
+ if (ossl_cipher_ctx_init(&ctx, nid) < 0)
+ goto fail_cipher;
- /* Extract phase from IV bit 7 and check for key rotation */
- rx_phase = (iv[0] & 0x80) ? 1 : 0;
+ if (in.len < (size_t) ctx.tagsz)
+ goto fail_ctx;
- if (should_rotate_key_rx(ctx, rx_phase)) {
- if (rotate_key(ctx) != 0)
- goto fail_decrypt;
- }
+ in_sz = (int) in.len - ctx.tagsz;
- ctx->rot.cntr++;
- ctx->rot.age++;
+ out->data = malloc((size_t) in_sz + EVP_MAX_BLOCK_LENGTH);
+ if (out->data == NULL)
+ goto fail_ctx;
- if (try_decrypt(ctx, ctx->keys.cur, iv, input, in_sz, out->data,
- &out_sz) != 0) {
- if (ctx->keys.prv == NULL)
- goto fail_decrypt;
- if (try_decrypt(ctx, ctx->keys.prv, iv, input, in_sz,
- out->data, &out_sz) != 0)
- goto fail_decrypt;
- }
+ ct.data = in.data;
+ ct.len = (size_t) in_sz;
+ tag = in.data + in_sz;
- assert(out_sz <= in_sz);
+ if (openssl_open(&ctx, key, nonce, aad, ct, tag, out) < 0)
+ goto fail_open;
- out->len = (size_t) out_sz;
+ EVP_CIPHER_CTX_free(ctx.evp_ctx);
return 0;
- fail_decrypt:
+
+ fail_open:
free(out->data);
- fail_malloc:
+ fail_ctx:
+ EVP_CIPHER_CTX_free(ctx.evp_ctx);
+ fail_cipher:
clrbuf(*out);
return -ECRYPT;
}
@@ -1094,51 +1091,19 @@ struct ossl_crypt_ctx * openssl_crypt_create_ctx(struct crypt_sk * sk)
assert(sk != NULL);
assert(sk->key != NULL);
- assert(sk->rot_bit > 0 && sk->rot_bit < 32);
ctx = malloc(sizeof(*ctx));
if (ctx == NULL)
- goto fail_malloc;
+ goto fail_malloc;
memset(ctx, 0, sizeof(*ctx));
- ctx->keys.cur = OPENSSL_secure_malloc(SYMMKEYSZ);
- if (ctx->keys.cur == NULL)
- goto fail_key;
-
- memcpy(ctx->keys.cur, sk->key, SYMMKEYSZ);
-
- ctx->keys.prv = NULL;
-
- /* Derive rotation salt from initial shared secret */
- if (EVP_Digest(sk->key, SYMMKEYSZ, ctx->rot.salt, NULL,
- EVP_sha256(), NULL) != 1)
- goto fail_cipher;
-
- ctx->cipher = EVP_get_cipherbynid(sk->nid);
- if (ctx->cipher == NULL)
- goto fail_cipher;
-
- ctx->ivsz = EVP_CIPHER_iv_length(ctx->cipher);
-
- /* Set tag size for AEAD ciphers (GCM, CCM, OCB, ChaCha20-Poly1305) */
- if (EVP_CIPHER_flags(ctx->cipher) & EVP_CIPH_FLAG_AEAD_CIPHER)
- ctx->tagsz = 16; /* Standard AEAD tag length (128 bits) */
-
- ctx->rot.cntr = 0;
- ctx->rot.mask = (1U << sk->rot_bit);
- ctx->rot.age = 0;
- ctx->rot.phase = 0;
-
- ctx->evp_ctx = EVP_CIPHER_CTX_new();
- if (ctx->evp_ctx == NULL)
+ if (ossl_cipher_ctx_init(ctx, sk->nid) < 0)
goto fail_cipher;
return ctx;
fail_cipher:
- OPENSSL_secure_clear_free(ctx->keys.cur, SYMMKEYSZ);
- fail_key:
free(ctx);
fail_malloc:
return NULL;
@@ -1149,23 +1114,10 @@ void openssl_crypt_destroy_ctx(struct ossl_crypt_ctx * ctx)
if (ctx == NULL)
return;
- if (ctx->keys.cur != NULL)
- OPENSSL_secure_clear_free(ctx->keys.cur, SYMMKEYSZ);
-
- if (ctx->keys.prv != NULL)
- OPENSSL_secure_clear_free(ctx->keys.prv, SYMMKEYSZ);
-
EVP_CIPHER_CTX_free(ctx->evp_ctx);
free(ctx);
}
-int openssl_crypt_get_ivsz(struct ossl_crypt_ctx * ctx)
-{
- assert(ctx != NULL);
-
- return ctx->ivsz;
-}
-
int openssl_crypt_get_tagsz(struct ossl_crypt_ctx * ctx)
{
assert(ctx != NULL);
@@ -1937,9 +1889,10 @@ void * openssl_secure_malloc(size_t size)
return OPENSSL_secure_malloc(size);
}
-void openssl_secure_free(void * ptr)
+void openssl_secure_free(void * ptr,
+ size_t size)
{
- OPENSSL_secure_free(ptr);
+ OPENSSL_secure_clear_free(ptr, size);
}
void openssl_secure_clear(void * ptr,
@@ -1947,6 +1900,7 @@ void openssl_secure_clear(void * ptr,
{
OPENSSL_cleanse(ptr, size);
}
+
void openssl_cleanup(void)
{
OPENSSL_cleanup();
diff --git a/src/lib/crypt/openssl.h b/src/lib/crypt/openssl.h
index 2578a0d2..e5cc35f7 100644
--- a/src/lib/crypt/openssl.h
+++ b/src/lib/crypt/openssl.h
@@ -61,20 +61,44 @@ int openssl_get_algo_from_pk_der(buffer_t pk,
int openssl_get_algo_from_pk_raw(buffer_t pk,
char * algo);
-int openssl_encrypt(struct ossl_crypt_ctx * ctx,
- buffer_t in,
- buffer_t * out);
-
-int openssl_decrypt(struct ossl_crypt_ctx * ctx,
- buffer_t in,
- buffer_t * out);
+int openssl_seal(struct ossl_crypt_ctx * ctx,
+ const uint8_t * key,
+ const uint8_t * nonce,
+ buffer_t aad,
+ buffer_t in,
+ uint8_t * out,
+ uint8_t * tag);
+
+int openssl_open(struct ossl_crypt_ctx * ctx,
+ const uint8_t * key,
+ const uint8_t * nonce,
+ buffer_t aad,
+ buffer_t in,
+ const uint8_t * tag,
+ buffer_t * out);
+
+int openssl_oneshot_seal(int nid,
+ const uint8_t * key,
+ const uint8_t * nonce,
+ buffer_t aad,
+ buffer_t in,
+ buffer_t * out);
+
+int openssl_oneshot_open(int nid,
+ const uint8_t * key,
+ const uint8_t * nonce,
+ buffer_t aad,
+ buffer_t in,
+ buffer_t * out);
+
+int openssl_hkdf_expand(buffer_t key,
+ buffer_t info,
+ buffer_t out);
struct ossl_crypt_ctx * openssl_crypt_create_ctx(struct crypt_sk * sk);
void openssl_crypt_destroy_ctx(struct ossl_crypt_ctx * ctx);
-int openssl_crypt_get_ivsz(struct ossl_crypt_ctx * ctx);
-
int openssl_crypt_get_tagsz(struct ossl_crypt_ctx * ctx);
/* AUTHENTICATION */
generated by cgit v1.2.3 (git 2.39.1) at 2026-07-01 09:29:34 +0000