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-rw-r--r--sshkey-xmss.c1055
1 files changed, 1055 insertions, 0 deletions
diff --git a/sshkey-xmss.c b/sshkey-xmss.c
new file mode 100644
index 0000000..aaae702
--- /dev/null
+++ b/sshkey-xmss.c
@@ -0,0 +1,1055 @@
+/* $OpenBSD: sshkey-xmss.c,v 1.3 2018/07/09 21:59:10 markus Exp $ */
+/*
+ * Copyright (c) 2017 Markus Friedl. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+#ifdef WITH_XMSS
+
+#include <sys/types.h>
+#include <sys/uio.h>
+
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#ifdef HAVE_SYS_FILE_H
+# include <sys/file.h>
+#endif
+
+#include "ssh2.h"
+#include "ssherr.h"
+#include "sshbuf.h"
+#include "cipher.h"
+#include "sshkey.h"
+#include "sshkey-xmss.h"
+#include "atomicio.h"
+
+#include "xmss_fast.h"
+
+/* opaque internal XMSS state */
+#define XMSS_MAGIC "xmss-state-v1"
+#define XMSS_CIPHERNAME "aes256-gcm@openssh.com"
+struct ssh_xmss_state {
+ xmss_params params;
+ u_int32_t n, w, h, k;
+
+ bds_state bds;
+ u_char *stack;
+ u_int32_t stackoffset;
+ u_char *stacklevels;
+ u_char *auth;
+ u_char *keep;
+ u_char *th_nodes;
+ u_char *retain;
+ treehash_inst *treehash;
+
+ u_int32_t idx; /* state read from file */
+ u_int32_t maxidx; /* restricted # of signatures */
+ int have_state; /* .state file exists */
+ int lockfd; /* locked in sshkey_xmss_get_state() */
+ int allow_update; /* allow sshkey_xmss_update_state() */
+ char *enc_ciphername;/* encrypt state with cipher */
+ u_char *enc_keyiv; /* encrypt state with key */
+ u_int32_t enc_keyiv_len; /* length of enc_keyiv */
+};
+
+int sshkey_xmss_init_bds_state(struct sshkey *);
+int sshkey_xmss_init_enc_key(struct sshkey *, const char *);
+void sshkey_xmss_free_bds(struct sshkey *);
+int sshkey_xmss_get_state_from_file(struct sshkey *, const char *,
+ int *, sshkey_printfn *);
+int sshkey_xmss_encrypt_state(const struct sshkey *, struct sshbuf *,
+ struct sshbuf **);
+int sshkey_xmss_decrypt_state(const struct sshkey *, struct sshbuf *,
+ struct sshbuf **);
+int sshkey_xmss_serialize_enc_key(const struct sshkey *, struct sshbuf *);
+int sshkey_xmss_deserialize_enc_key(struct sshkey *, struct sshbuf *);
+
+#define PRINT(s...) do { if (pr) pr(s); } while (0)
+
+int
+sshkey_xmss_init(struct sshkey *key, const char *name)
+{
+ struct ssh_xmss_state *state;
+
+ if (key->xmss_state != NULL)
+ return SSH_ERR_INVALID_FORMAT;
+ if (name == NULL)
+ return SSH_ERR_INVALID_FORMAT;
+ state = calloc(sizeof(struct ssh_xmss_state), 1);
+ if (state == NULL)
+ return SSH_ERR_ALLOC_FAIL;
+ if (strcmp(name, XMSS_SHA2_256_W16_H10_NAME) == 0) {
+ state->n = 32;
+ state->w = 16;
+ state->h = 10;
+ } else if (strcmp(name, XMSS_SHA2_256_W16_H16_NAME) == 0) {
+ state->n = 32;
+ state->w = 16;
+ state->h = 16;
+ } else if (strcmp(name, XMSS_SHA2_256_W16_H20_NAME) == 0) {
+ state->n = 32;
+ state->w = 16;
+ state->h = 20;
+ } else {
+ free(state);
+ return SSH_ERR_KEY_TYPE_UNKNOWN;
+ }
+ if ((key->xmss_name = strdup(name)) == NULL) {
+ free(state);
+ return SSH_ERR_ALLOC_FAIL;
+ }
+ state->k = 2; /* XXX hardcoded */
+ state->lockfd = -1;
+ if (xmss_set_params(&state->params, state->n, state->h, state->w,
+ state->k) != 0) {
+ free(state);
+ return SSH_ERR_INVALID_FORMAT;
+ }
+ key->xmss_state = state;
+ return 0;
+}
+
+void
+sshkey_xmss_free_state(struct sshkey *key)
+{
+ struct ssh_xmss_state *state = key->xmss_state;
+
+ sshkey_xmss_free_bds(key);
+ if (state) {
+ if (state->enc_keyiv) {
+ explicit_bzero(state->enc_keyiv, state->enc_keyiv_len);
+ free(state->enc_keyiv);
+ }
+ free(state->enc_ciphername);
+ free(state);
+ }
+ key->xmss_state = NULL;
+}
+
+#define SSH_XMSS_K2_MAGIC "k=2"
+#define num_stack(x) ((x->h+1)*(x->n))
+#define num_stacklevels(x) (x->h+1)
+#define num_auth(x) ((x->h)*(x->n))
+#define num_keep(x) ((x->h >> 1)*(x->n))
+#define num_th_nodes(x) ((x->h - x->k)*(x->n))
+#define num_retain(x) (((1ULL << x->k) - x->k - 1) * (x->n))
+#define num_treehash(x) ((x->h) - (x->k))
+
+int
+sshkey_xmss_init_bds_state(struct sshkey *key)
+{
+ struct ssh_xmss_state *state = key->xmss_state;
+ u_int32_t i;
+
+ state->stackoffset = 0;
+ if ((state->stack = calloc(num_stack(state), 1)) == NULL ||
+ (state->stacklevels = calloc(num_stacklevels(state), 1))== NULL ||
+ (state->auth = calloc(num_auth(state), 1)) == NULL ||
+ (state->keep = calloc(num_keep(state), 1)) == NULL ||
+ (state->th_nodes = calloc(num_th_nodes(state), 1)) == NULL ||
+ (state->retain = calloc(num_retain(state), 1)) == NULL ||
+ (state->treehash = calloc(num_treehash(state),
+ sizeof(treehash_inst))) == NULL) {
+ sshkey_xmss_free_bds(key);
+ return SSH_ERR_ALLOC_FAIL;
+ }
+ for (i = 0; i < state->h - state->k; i++)
+ state->treehash[i].node = &state->th_nodes[state->n*i];
+ xmss_set_bds_state(&state->bds, state->stack, state->stackoffset,
+ state->stacklevels, state->auth, state->keep, state->treehash,
+ state->retain, 0);
+ return 0;
+}
+
+void
+sshkey_xmss_free_bds(struct sshkey *key)
+{
+ struct ssh_xmss_state *state = key->xmss_state;
+
+ if (state == NULL)
+ return;
+ free(state->stack);
+ free(state->stacklevels);
+ free(state->auth);
+ free(state->keep);
+ free(state->th_nodes);
+ free(state->retain);
+ free(state->treehash);
+ state->stack = NULL;
+ state->stacklevels = NULL;
+ state->auth = NULL;
+ state->keep = NULL;
+ state->th_nodes = NULL;
+ state->retain = NULL;
+ state->treehash = NULL;
+}
+
+void *
+sshkey_xmss_params(const struct sshkey *key)
+{
+ struct ssh_xmss_state *state = key->xmss_state;
+
+ if (state == NULL)
+ return NULL;
+ return &state->params;
+}
+
+void *
+sshkey_xmss_bds_state(const struct sshkey *key)
+{
+ struct ssh_xmss_state *state = key->xmss_state;
+
+ if (state == NULL)
+ return NULL;
+ return &state->bds;
+}
+
+int
+sshkey_xmss_siglen(const struct sshkey *key, size_t *lenp)
+{
+ struct ssh_xmss_state *state = key->xmss_state;
+
+ if (lenp == NULL)
+ return SSH_ERR_INVALID_ARGUMENT;
+ if (state == NULL)
+ return SSH_ERR_INVALID_FORMAT;
+ *lenp = 4 + state->n +
+ state->params.wots_par.keysize +
+ state->h * state->n;
+ return 0;
+}
+
+size_t
+sshkey_xmss_pklen(const struct sshkey *key)
+{
+ struct ssh_xmss_state *state = key->xmss_state;
+
+ if (state == NULL)
+ return 0;
+ return state->n * 2;
+}
+
+size_t
+sshkey_xmss_sklen(const struct sshkey *key)
+{
+ struct ssh_xmss_state *state = key->xmss_state;
+
+ if (state == NULL)
+ return 0;
+ return state->n * 4 + 4;
+}
+
+int
+sshkey_xmss_init_enc_key(struct sshkey *k, const char *ciphername)
+{
+ struct ssh_xmss_state *state = k->xmss_state;
+ const struct sshcipher *cipher;
+ size_t keylen = 0, ivlen = 0;
+
+ if (state == NULL)
+ return SSH_ERR_INVALID_ARGUMENT;
+ if ((cipher = cipher_by_name(ciphername)) == NULL)
+ return SSH_ERR_INTERNAL_ERROR;
+ if ((state->enc_ciphername = strdup(ciphername)) == NULL)
+ return SSH_ERR_ALLOC_FAIL;
+ keylen = cipher_keylen(cipher);
+ ivlen = cipher_ivlen(cipher);
+ state->enc_keyiv_len = keylen + ivlen;
+ if ((state->enc_keyiv = calloc(state->enc_keyiv_len, 1)) == NULL) {
+ free(state->enc_ciphername);
+ state->enc_ciphername = NULL;
+ return SSH_ERR_ALLOC_FAIL;
+ }
+ arc4random_buf(state->enc_keyiv, state->enc_keyiv_len);
+ return 0;
+}
+
+int
+sshkey_xmss_serialize_enc_key(const struct sshkey *k, struct sshbuf *b)
+{
+ struct ssh_xmss_state *state = k->xmss_state;
+ int r;
+
+ if (state == NULL || state->enc_keyiv == NULL ||
+ state->enc_ciphername == NULL)
+ return SSH_ERR_INVALID_ARGUMENT;
+ if ((r = sshbuf_put_cstring(b, state->enc_ciphername)) != 0 ||
+ (r = sshbuf_put_string(b, state->enc_keyiv,
+ state->enc_keyiv_len)) != 0)
+ return r;
+ return 0;
+}
+
+int
+sshkey_xmss_deserialize_enc_key(struct sshkey *k, struct sshbuf *b)
+{
+ struct ssh_xmss_state *state = k->xmss_state;
+ size_t len;
+ int r;
+
+ if (state == NULL)
+ return SSH_ERR_INVALID_ARGUMENT;
+ if ((r = sshbuf_get_cstring(b, &state->enc_ciphername, NULL)) != 0 ||
+ (r = sshbuf_get_string(b, &state->enc_keyiv, &len)) != 0)
+ return r;
+ state->enc_keyiv_len = len;
+ return 0;
+}
+
+int
+sshkey_xmss_serialize_pk_info(const struct sshkey *k, struct sshbuf *b,
+ enum sshkey_serialize_rep opts)
+{
+ struct ssh_xmss_state *state = k->xmss_state;
+ u_char have_info = 1;
+ u_int32_t idx;
+ int r;
+
+ if (state == NULL)
+ return SSH_ERR_INVALID_ARGUMENT;
+ if (opts != SSHKEY_SERIALIZE_INFO)
+ return 0;
+ idx = k->xmss_sk ? PEEK_U32(k->xmss_sk) : state->idx;
+ if ((r = sshbuf_put_u8(b, have_info)) != 0 ||
+ (r = sshbuf_put_u32(b, idx)) != 0 ||
+ (r = sshbuf_put_u32(b, state->maxidx)) != 0)
+ return r;
+ return 0;
+}
+
+int
+sshkey_xmss_deserialize_pk_info(struct sshkey *k, struct sshbuf *b)
+{
+ struct ssh_xmss_state *state = k->xmss_state;
+ u_char have_info;
+ int r;
+
+ if (state == NULL)
+ return SSH_ERR_INVALID_ARGUMENT;
+ /* optional */
+ if (sshbuf_len(b) == 0)
+ return 0;
+ if ((r = sshbuf_get_u8(b, &have_info)) != 0)
+ return r;
+ if (have_info != 1)
+ return SSH_ERR_INVALID_ARGUMENT;
+ if ((r = sshbuf_get_u32(b, &state->idx)) != 0 ||
+ (r = sshbuf_get_u32(b, &state->maxidx)) != 0)
+ return r;
+ return 0;
+}
+
+int
+sshkey_xmss_generate_private_key(struct sshkey *k, u_int bits)
+{
+ int r;
+ const char *name;
+
+ if (bits == 10) {
+ name = XMSS_SHA2_256_W16_H10_NAME;
+ } else if (bits == 16) {
+ name = XMSS_SHA2_256_W16_H16_NAME;
+ } else if (bits == 20) {
+ name = XMSS_SHA2_256_W16_H20_NAME;
+ } else {
+ name = XMSS_DEFAULT_NAME;
+ }
+ if ((r = sshkey_xmss_init(k, name)) != 0 ||
+ (r = sshkey_xmss_init_bds_state(k)) != 0 ||
+ (r = sshkey_xmss_init_enc_key(k, XMSS_CIPHERNAME)) != 0)
+ return r;
+ if ((k->xmss_pk = malloc(sshkey_xmss_pklen(k))) == NULL ||
+ (k->xmss_sk = malloc(sshkey_xmss_sklen(k))) == NULL) {
+ return SSH_ERR_ALLOC_FAIL;
+ }
+ xmss_keypair(k->xmss_pk, k->xmss_sk, sshkey_xmss_bds_state(k),
+ sshkey_xmss_params(k));
+ return 0;
+}
+
+int
+sshkey_xmss_get_state_from_file(struct sshkey *k, const char *filename,
+ int *have_file, sshkey_printfn *pr)
+{
+ struct sshbuf *b = NULL, *enc = NULL;
+ int ret = SSH_ERR_SYSTEM_ERROR, r, fd = -1;
+ u_int32_t len;
+ unsigned char buf[4], *data = NULL;
+
+ *have_file = 0;
+ if ((fd = open(filename, O_RDONLY)) >= 0) {
+ *have_file = 1;
+ if (atomicio(read, fd, buf, sizeof(buf)) != sizeof(buf)) {
+ PRINT("%s: corrupt state file: %s", __func__, filename);
+ goto done;
+ }
+ len = PEEK_U32(buf);
+ if ((data = calloc(len, 1)) == NULL) {
+ ret = SSH_ERR_ALLOC_FAIL;
+ goto done;
+ }
+ if (atomicio(read, fd, data, len) != len) {
+ PRINT("%s: cannot read blob: %s", __func__, filename);
+ goto done;
+ }
+ if ((enc = sshbuf_from(data, len)) == NULL) {
+ ret = SSH_ERR_ALLOC_FAIL;
+ goto done;
+ }
+ sshkey_xmss_free_bds(k);
+ if ((r = sshkey_xmss_decrypt_state(k, enc, &b)) != 0) {
+ ret = r;
+ goto done;
+ }
+ if ((r = sshkey_xmss_deserialize_state(k, b)) != 0) {
+ ret = r;
+ goto done;
+ }
+ ret = 0;
+ }
+done:
+ if (fd != -1)
+ close(fd);
+ free(data);
+ sshbuf_free(enc);
+ sshbuf_free(b);
+ return ret;
+}
+
+int
+sshkey_xmss_get_state(const struct sshkey *k, sshkey_printfn *pr)
+{
+ struct ssh_xmss_state *state = k->xmss_state;
+ u_int32_t idx = 0;
+ char *filename = NULL;
+ char *statefile = NULL, *ostatefile = NULL, *lockfile = NULL;
+ int lockfd = -1, have_state = 0, have_ostate, tries = 0;
+ int ret = SSH_ERR_INVALID_ARGUMENT, r;
+
+ if (state == NULL)
+ goto done;
+ /*
+ * If maxidx is set, then we are allowed a limited number
+ * of signatures, but don't need to access the disk.
+ * Otherwise we need to deal with the on-disk state.
+ */
+ if (state->maxidx) {
+ /* xmss_sk always contains the current state */
+ idx = PEEK_U32(k->xmss_sk);
+ if (idx < state->maxidx) {
+ state->allow_update = 1;
+ return 0;
+ }
+ return SSH_ERR_INVALID_ARGUMENT;
+ }
+ if ((filename = k->xmss_filename) == NULL)
+ goto done;
+ if (asprintf(&lockfile, "%s.lock", filename) < 0 ||
+ asprintf(&statefile, "%s.state", filename) < 0 ||
+ asprintf(&ostatefile, "%s.ostate", filename) < 0) {
+ ret = SSH_ERR_ALLOC_FAIL;
+ goto done;
+ }
+ if ((lockfd = open(lockfile, O_CREAT|O_RDONLY, 0600)) < 0) {
+ ret = SSH_ERR_SYSTEM_ERROR;
+ PRINT("%s: cannot open/create: %s", __func__, lockfile);
+ goto done;
+ }
+ while (flock(lockfd, LOCK_EX|LOCK_NB) < 0) {
+ if (errno != EWOULDBLOCK) {
+ ret = SSH_ERR_SYSTEM_ERROR;
+ PRINT("%s: cannot lock: %s", __func__, lockfile);
+ goto done;
+ }
+ if (++tries > 10) {
+ ret = SSH_ERR_SYSTEM_ERROR;
+ PRINT("%s: giving up on: %s", __func__, lockfile);
+ goto done;
+ }
+ usleep(1000*100*tries);
+ }
+ /* XXX no longer const */
+ if ((r = sshkey_xmss_get_state_from_file((struct sshkey *)k,
+ statefile, &have_state, pr)) != 0) {
+ if ((r = sshkey_xmss_get_state_from_file((struct sshkey *)k,
+ ostatefile, &have_ostate, pr)) == 0) {
+ state->allow_update = 1;
+ r = sshkey_xmss_forward_state(k, 1);
+ state->idx = PEEK_U32(k->xmss_sk);
+ state->allow_update = 0;
+ }
+ }
+ if (!have_state && !have_ostate) {
+ /* check that bds state is initialized */
+ if (state->bds.auth == NULL)
+ goto done;
+ PRINT("%s: start from scratch idx 0: %u", __func__, state->idx);
+ } else if (r != 0) {
+ ret = r;
+ goto done;
+ }
+ if (state->idx + 1 < state->idx) {
+ PRINT("%s: state wrap: %u", __func__, state->idx);
+ goto done;
+ }
+ state->have_state = have_state;
+ state->lockfd = lockfd;
+ state->allow_update = 1;
+ lockfd = -1;
+ ret = 0;
+done:
+ if (lockfd != -1)
+ close(lockfd);
+ free(lockfile);
+ free(statefile);
+ free(ostatefile);
+ return ret;
+}
+
+int
+sshkey_xmss_forward_state(const struct sshkey *k, u_int32_t reserve)
+{
+ struct ssh_xmss_state *state = k->xmss_state;
+ u_char *sig = NULL;
+ size_t required_siglen;
+ unsigned long long smlen;
+ u_char data;
+ int ret, r;
+
+ if (state == NULL || !state->allow_update)
+ return SSH_ERR_INVALID_ARGUMENT;
+ if (reserve == 0)
+ return SSH_ERR_INVALID_ARGUMENT;
+ if (state->idx + reserve <= state->idx)
+ return SSH_ERR_INVALID_ARGUMENT;
+ if ((r = sshkey_xmss_siglen(k, &required_siglen)) != 0)
+ return r;
+ if ((sig = malloc(required_siglen)) == NULL)
+ return SSH_ERR_ALLOC_FAIL;
+ while (reserve-- > 0) {
+ state->idx = PEEK_U32(k->xmss_sk);
+ smlen = required_siglen;
+ if ((ret = xmss_sign(k->xmss_sk, sshkey_xmss_bds_state(k),
+ sig, &smlen, &data, 0, sshkey_xmss_params(k))) != 0) {
+ r = SSH_ERR_INVALID_ARGUMENT;
+ break;
+ }
+ }
+ free(sig);
+ return r;
+}
+
+int
+sshkey_xmss_update_state(const struct sshkey *k, sshkey_printfn *pr)
+{
+ struct ssh_xmss_state *state = k->xmss_state;
+ struct sshbuf *b = NULL, *enc = NULL;
+ u_int32_t idx = 0;
+ unsigned char buf[4];
+ char *filename = NULL;
+ char *statefile = NULL, *ostatefile = NULL, *nstatefile = NULL;
+ int fd = -1;
+ int ret = SSH_ERR_INVALID_ARGUMENT;
+
+ if (state == NULL || !state->allow_update)
+ return ret;
+ if (state->maxidx) {
+ /* no update since the number of signatures is limited */
+ ret = 0;
+ goto done;
+ }
+ idx = PEEK_U32(k->xmss_sk);
+ if (idx == state->idx) {
+ /* no signature happened, no need to update */
+ ret = 0;
+ goto done;
+ } else if (idx != state->idx + 1) {
+ PRINT("%s: more than one signature happened: idx %u state %u",
+ __func__, idx, state->idx);
+ goto done;
+ }
+ state->idx = idx;
+ if ((filename = k->xmss_filename) == NULL)
+ goto done;
+ if (asprintf(&statefile, "%s.state", filename) < 0 ||
+ asprintf(&ostatefile, "%s.ostate", filename) < 0 ||
+ asprintf(&nstatefile, "%s.nstate", filename) < 0) {
+ ret = SSH_ERR_ALLOC_FAIL;
+ goto done;
+ }
+ unlink(nstatefile);
+ if ((b = sshbuf_new()) == NULL) {
+ ret = SSH_ERR_ALLOC_FAIL;
+ goto done;
+ }
+ if ((ret = sshkey_xmss_serialize_state(k, b)) != 0) {
+ PRINT("%s: SERLIALIZE FAILED: %d", __func__, ret);
+ goto done;
+ }
+ if ((ret = sshkey_xmss_encrypt_state(k, b, &enc)) != 0) {
+ PRINT("%s: ENCRYPT FAILED: %d", __func__, ret);
+ goto done;
+ }
+ if ((fd = open(nstatefile, O_CREAT|O_WRONLY|O_EXCL, 0600)) < 0) {
+ ret = SSH_ERR_SYSTEM_ERROR;
+ PRINT("%s: open new state file: %s", __func__, nstatefile);
+ goto done;
+ }
+ POKE_U32(buf, sshbuf_len(enc));
+ if (atomicio(vwrite, fd, buf, sizeof(buf)) != sizeof(buf)) {
+ ret = SSH_ERR_SYSTEM_ERROR;
+ PRINT("%s: write new state file hdr: %s", __func__, nstatefile);
+ close(fd);
+ goto done;
+ }
+ if (atomicio(vwrite, fd, sshbuf_mutable_ptr(enc), sshbuf_len(enc)) !=
+ sshbuf_len(enc)) {
+ ret = SSH_ERR_SYSTEM_ERROR;
+ PRINT("%s: write new state file data: %s", __func__, nstatefile);
+ close(fd);
+ goto done;
+ }
+ if (fsync(fd) < 0) {
+ ret = SSH_ERR_SYSTEM_ERROR;
+ PRINT("%s: sync new state file: %s", __func__, nstatefile);
+ close(fd);
+ goto done;
+ }
+ if (close(fd) < 0) {
+ ret = SSH_ERR_SYSTEM_ERROR;
+ PRINT("%s: close new state file: %s", __func__, nstatefile);
+ goto done;
+ }
+ if (state->have_state) {
+ unlink(ostatefile);
+ if (link(statefile, ostatefile)) {
+ ret = SSH_ERR_SYSTEM_ERROR;
+ PRINT("%s: backup state %s to %s", __func__, statefile,
+ ostatefile);
+ goto done;
+ }
+ }
+ if (rename(nstatefile, statefile) < 0) {
+ ret = SSH_ERR_SYSTEM_ERROR;
+ PRINT("%s: rename %s to %s", __func__, nstatefile, statefile);
+ goto done;
+ }
+ ret = 0;
+done:
+ if (state->lockfd != -1) {
+ close(state->lockfd);
+ state->lockfd = -1;
+ }
+ if (nstatefile)
+ unlink(nstatefile);
+ free(statefile);
+ free(ostatefile);
+ free(nstatefile);
+ sshbuf_free(b);
+ sshbuf_free(enc);
+ return ret;
+}
+
+int
+sshkey_xmss_serialize_state(const struct sshkey *k, struct sshbuf *b)
+{
+ struct ssh_xmss_state *state = k->xmss_state;
+ treehash_inst *th;
+ u_int32_t i, node;
+ int r;
+
+ if (state == NULL)
+ return SSH_ERR_INVALID_ARGUMENT;
+ if (state->stack == NULL)
+ return SSH_ERR_INVALID_ARGUMENT;
+ state->stackoffset = state->bds.stackoffset; /* copy back */
+ if ((r = sshbuf_put_cstring(b, SSH_XMSS_K2_MAGIC)) != 0 ||
+ (r = sshbuf_put_u32(b, state->idx)) != 0 ||
+ (r = sshbuf_put_string(b, state->stack, num_stack(state))) != 0 ||
+ (r = sshbuf_put_u32(b, state->stackoffset)) != 0 ||
+ (r = sshbuf_put_string(b, state->stacklevels, num_stacklevels(state))) != 0 ||
+ (r = sshbuf_put_string(b, state->auth, num_auth(state))) != 0 ||
+ (r = sshbuf_put_string(b, state->keep, num_keep(state))) != 0 ||
+ (r = sshbuf_put_string(b, state->th_nodes, num_th_nodes(state))) != 0 ||
+ (r = sshbuf_put_string(b, state->retain, num_retain(state))) != 0 ||
+ (r = sshbuf_put_u32(b, num_treehash(state))) != 0)
+ return r;
+ for (i = 0; i < num_treehash(state); i++) {
+ th = &state->treehash[i];
+ node = th->node - state->th_nodes;
+ if ((r = sshbuf_put_u32(b, th->h)) != 0 ||
+ (r = sshbuf_put_u32(b, th->next_idx)) != 0 ||
+ (r = sshbuf_put_u32(b, th->stackusage)) != 0 ||
+ (r = sshbuf_put_u8(b, th->completed)) != 0 ||
+ (r = sshbuf_put_u32(b, node)) != 0)
+ return r;
+ }
+ return 0;
+}
+
+int
+sshkey_xmss_serialize_state_opt(const struct sshkey *k, struct sshbuf *b,
+ enum sshkey_serialize_rep opts)
+{
+ struct ssh_xmss_state *state = k->xmss_state;
+ int r = SSH_ERR_INVALID_ARGUMENT;
+
+ if (state == NULL)
+ return SSH_ERR_INVALID_ARGUMENT;
+ if ((r = sshbuf_put_u8(b, opts)) != 0)
+ return r;
+ switch (opts) {
+ case SSHKEY_SERIALIZE_STATE:
+ r = sshkey_xmss_serialize_state(k, b);
+ break;
+ case SSHKEY_SERIALIZE_FULL:
+ if ((r = sshkey_xmss_serialize_enc_key(k, b)) != 0)
+ break;
+ r = sshkey_xmss_serialize_state(k, b);
+ break;
+ case SSHKEY_SERIALIZE_DEFAULT:
+ r = 0;
+ break;
+ default:
+ r = SSH_ERR_INVALID_ARGUMENT;
+ break;
+ }
+ return r;
+}
+
+int
+sshkey_xmss_deserialize_state(struct sshkey *k, struct sshbuf *b)
+{
+ struct ssh_xmss_state *state = k->xmss_state;
+ treehash_inst *th;
+ u_int32_t i, lh, node;
+ size_t ls, lsl, la, lk, ln, lr;
+ char *magic;
+ int r;
+
+ if (state == NULL)
+ return SSH_ERR_INVALID_ARGUMENT;
+ if (k->xmss_sk == NULL)
+ return SSH_ERR_INVALID_ARGUMENT;
+ if ((state->treehash = calloc(num_treehash(state),
+ sizeof(treehash_inst))) == NULL)
+ return SSH_ERR_ALLOC_FAIL;
+ if ((r = sshbuf_get_cstring(b, &magic, NULL)) != 0 ||
+ (r = sshbuf_get_u32(b, &state->idx)) != 0 ||
+ (r = sshbuf_get_string(b, &state->stack, &ls)) != 0 ||
+ (r = sshbuf_get_u32(b, &state->stackoffset)) != 0 ||
+ (r = sshbuf_get_string(b, &state->stacklevels, &lsl)) != 0 ||
+ (r = sshbuf_get_string(b, &state->auth, &la)) != 0 ||
+ (r = sshbuf_get_string(b, &state->keep, &lk)) != 0 ||
+ (r = sshbuf_get_string(b, &state->th_nodes, &ln)) != 0 ||
+ (r = sshbuf_get_string(b, &state->retain, &lr)) != 0 ||
+ (r = sshbuf_get_u32(b, &lh)) != 0)
+ return r;
+ if (strcmp(magic, SSH_XMSS_K2_MAGIC) != 0)
+ return SSH_ERR_INVALID_ARGUMENT;
+ /* XXX check stackoffset */
+ if (ls != num_stack(state) ||
+ lsl != num_stacklevels(state) ||
+ la != num_auth(state) ||
+ lk != num_keep(state) ||
+ ln != num_th_nodes(state) ||
+ lr != num_retain(state) ||
+ lh != num_treehash(state))
+ return SSH_ERR_INVALID_ARGUMENT;
+ for (i = 0; i < num_treehash(state); i++) {
+ th = &state->treehash[i];
+ if ((r = sshbuf_get_u32(b, &th->h)) != 0 ||
+ (r = sshbuf_get_u32(b, &th->next_idx)) != 0 ||
+ (r = sshbuf_get_u32(b, &th->stackusage)) != 0 ||
+ (r = sshbuf_get_u8(b, &th->completed)) != 0 ||
+ (r = sshbuf_get_u32(b, &node)) != 0)
+ return r;
+ if (node < num_th_nodes(state))
+ th->node = &state->th_nodes[node];
+ }
+ POKE_U32(k->xmss_sk, state->idx);
+ xmss_set_bds_state(&state->bds, state->stack, state->stackoffset,
+ state->stacklevels, state->auth, state->keep, state->treehash,
+ state->retain, 0);
+ return 0;
+}
+
+int
+sshkey_xmss_deserialize_state_opt(struct sshkey *k, struct sshbuf *b)
+{
+ enum sshkey_serialize_rep opts;
+ u_char have_state;
+ int r;
+
+ if ((r = sshbuf_get_u8(b, &have_state)) != 0)
+ return r;
+
+ opts = have_state;
+ switch (opts) {
+ case SSHKEY_SERIALIZE_DEFAULT:
+ r = 0;
+ break;
+ case SSHKEY_SERIALIZE_STATE:
+ if ((r = sshkey_xmss_deserialize_state(k, b)) != 0)
+ return r;
+ break;
+ case SSHKEY_SERIALIZE_FULL:
+ if ((r = sshkey_xmss_deserialize_enc_key(k, b)) != 0 ||
+ (r = sshkey_xmss_deserialize_state(k, b)) != 0)
+ return r;
+ break;
+ default:
+ r = SSH_ERR_INVALID_FORMAT;
+ break;
+ }
+ return r;
+}
+
+int
+sshkey_xmss_encrypt_state(const struct sshkey *k, struct sshbuf *b,
+ struct sshbuf **retp)
+{
+ struct ssh_xmss_state *state = k->xmss_state;
+ struct sshbuf *encrypted = NULL, *encoded = NULL, *padded = NULL;
+ struct sshcipher_ctx *ciphercontext = NULL;
+ const struct sshcipher *cipher;
+ u_char *cp, *key, *iv = NULL;
+ size_t i, keylen, ivlen, blocksize, authlen, encrypted_len, aadlen;
+ int r = SSH_ERR_INTERNAL_ERROR;
+
+ if (retp != NULL)
+ *retp = NULL;
+ if (state == NULL ||
+ state->enc_keyiv == NULL ||
+ state->enc_ciphername == NULL)
+ return SSH_ERR_INTERNAL_ERROR;
+ if ((cipher = cipher_by_name(state->enc_ciphername)) == NULL) {
+ r = SSH_ERR_INTERNAL_ERROR;
+ goto out;
+ }
+ blocksize = cipher_blocksize(cipher);
+ keylen = cipher_keylen(cipher);
+ ivlen = cipher_ivlen(cipher);
+ authlen = cipher_authlen(cipher);
+ if (state->enc_keyiv_len != keylen + ivlen) {
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ key = state->enc_keyiv;
+ if ((encrypted = sshbuf_new()) == NULL ||
+ (encoded = sshbuf_new()) == NULL ||
+ (padded = sshbuf_new()) == NULL ||
+ (iv = malloc(ivlen)) == NULL) {
+ r = SSH_ERR_ALLOC_FAIL;
+ goto out;
+ }
+
+ /* replace first 4 bytes of IV with index to ensure uniqueness */
+ memcpy(iv, key + keylen, ivlen);
+ POKE_U32(iv, state->idx);
+
+ if ((r = sshbuf_put(encoded, XMSS_MAGIC, sizeof(XMSS_MAGIC))) != 0 ||
+ (r = sshbuf_put_u32(encoded, state->idx)) != 0)
+ goto out;
+
+ /* padded state will be encrypted */
+ if ((r = sshbuf_putb(padded, b)) != 0)
+ goto out;
+ i = 0;
+ while (sshbuf_len(padded) % blocksize) {
+ if ((r = sshbuf_put_u8(padded, ++i & 0xff)) != 0)
+ goto out;
+ }
+ encrypted_len = sshbuf_len(padded);
+
+ /* header including the length of state is used as AAD */
+ if ((r = sshbuf_put_u32(encoded, encrypted_len)) != 0)
+ goto out;
+ aadlen = sshbuf_len(encoded);
+
+ /* concat header and state */
+ if ((r = sshbuf_putb(encoded, padded)) != 0)
+ goto out;
+
+ /* reserve space for encryption of encoded data plus auth tag */
+ /* encrypt at offset addlen */
+ if ((r = sshbuf_reserve(encrypted,
+ encrypted_len + aadlen + authlen, &cp)) != 0 ||
+ (r = cipher_init(&ciphercontext, cipher, key, keylen,
+ iv, ivlen, 1)) != 0 ||
+ (r = cipher_crypt(ciphercontext, 0, cp, sshbuf_ptr(encoded),
+ encrypted_len, aadlen, authlen)) != 0)
+ goto out;
+
+ /* success */
+ r = 0;
+ out:
+ if (retp != NULL) {
+ *retp = encrypted;
+ encrypted = NULL;
+ }
+ sshbuf_free(padded);
+ sshbuf_free(encoded);
+ sshbuf_free(encrypted);
+ cipher_free(ciphercontext);
+ free(iv);
+ return r;
+}
+
+int
+sshkey_xmss_decrypt_state(const struct sshkey *k, struct sshbuf *encoded,
+ struct sshbuf **retp)
+{
+ struct ssh_xmss_state *state = k->xmss_state;
+ struct sshbuf *copy = NULL, *decrypted = NULL;
+ struct sshcipher_ctx *ciphercontext = NULL;
+ const struct sshcipher *cipher = NULL;
+ u_char *key, *iv = NULL, *dp;
+ size_t keylen, ivlen, authlen, aadlen;
+ u_int blocksize, encrypted_len, index;
+ int r = SSH_ERR_INTERNAL_ERROR;
+
+ if (retp != NULL)
+ *retp = NULL;
+ if (state == NULL ||
+ state->enc_keyiv == NULL ||
+ state->enc_ciphername == NULL)
+ return SSH_ERR_INTERNAL_ERROR;
+ if ((cipher = cipher_by_name(state->enc_ciphername)) == NULL) {
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ blocksize = cipher_blocksize(cipher);
+ keylen = cipher_keylen(cipher);
+ ivlen = cipher_ivlen(cipher);
+ authlen = cipher_authlen(cipher);
+ if (state->enc_keyiv_len != keylen + ivlen) {
+ r = SSH_ERR_INTERNAL_ERROR;
+ goto out;
+ }
+ key = state->enc_keyiv;
+
+ if ((copy = sshbuf_fromb(encoded)) == NULL ||
+ (decrypted = sshbuf_new()) == NULL ||
+ (iv = malloc(ivlen)) == NULL) {
+ r = SSH_ERR_ALLOC_FAIL;
+ goto out;
+ }
+
+ /* check magic */
+ if (sshbuf_len(encoded) < sizeof(XMSS_MAGIC) ||
+ memcmp(sshbuf_ptr(encoded), XMSS_MAGIC, sizeof(XMSS_MAGIC))) {
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ /* parse public portion */
+ if ((r = sshbuf_consume(encoded, sizeof(XMSS_MAGIC))) != 0 ||
+ (r = sshbuf_get_u32(encoded, &index)) != 0 ||
+ (r = sshbuf_get_u32(encoded, &encrypted_len)) != 0)
+ goto out;
+
+ /* check size of encrypted key blob */
+ if (encrypted_len < blocksize || (encrypted_len % blocksize) != 0) {
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ /* check that an appropriate amount of auth data is present */
+ if (sshbuf_len(encoded) < encrypted_len + authlen) {
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+
+ aadlen = sshbuf_len(copy) - sshbuf_len(encoded);
+
+ /* replace first 4 bytes of IV with index to ensure uniqueness */
+ memcpy(iv, key + keylen, ivlen);
+ POKE_U32(iv, index);
+
+ /* decrypt private state of key */
+ if ((r = sshbuf_reserve(decrypted, aadlen + encrypted_len, &dp)) != 0 ||
+ (r = cipher_init(&ciphercontext, cipher, key, keylen,
+ iv, ivlen, 0)) != 0 ||
+ (r = cipher_crypt(ciphercontext, 0, dp, sshbuf_ptr(copy),
+ encrypted_len, aadlen, authlen)) != 0)
+ goto out;
+
+ /* there should be no trailing data */
+ if ((r = sshbuf_consume(encoded, encrypted_len + authlen)) != 0)
+ goto out;
+ if (sshbuf_len(encoded) != 0) {
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+
+ /* remove AAD */
+ if ((r = sshbuf_consume(decrypted, aadlen)) != 0)
+ goto out;
+ /* XXX encrypted includes unchecked padding */
+
+ /* success */
+ r = 0;
+ if (retp != NULL) {
+ *retp = decrypted;
+ decrypted = NULL;
+ }
+ out:
+ cipher_free(ciphercontext);
+ sshbuf_free(copy);
+ sshbuf_free(decrypted);
+ free(iv);
+ return r;
+}
+
+u_int32_t
+sshkey_xmss_signatures_left(const struct sshkey *k)
+{
+ struct ssh_xmss_state *state = k->xmss_state;
+ u_int32_t idx;
+
+ if (sshkey_type_plain(k->type) == KEY_XMSS && state &&
+ state->maxidx) {
+ idx = k->xmss_sk ? PEEK_U32(k->xmss_sk) : state->idx;
+ if (idx < state->maxidx)
+ return state->maxidx - idx;
+ }
+ return 0;
+}
+
+int
+sshkey_xmss_enable_maxsign(struct sshkey *k, u_int32_t maxsign)
+{
+ struct ssh_xmss_state *state = k->xmss_state;
+
+ if (sshkey_type_plain(k->type) != KEY_XMSS)
+ return SSH_ERR_INVALID_ARGUMENT;
+ if (maxsign == 0)
+ return 0;
+ if (state->idx + maxsign < state->idx)
+ return SSH_ERR_INVALID_ARGUMENT;
+ state->maxidx = state->idx + maxsign;
+ return 0;
+}
+#endif /* WITH_XMSS */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 13:25:13 +0000