/* $OpenBSD: ssh-ed25519.c,v 1.6 2015/01/15 21:38:50 markus Exp $ */ /* * Copyright (c) 2013 Markus Friedl <markus@openbsd.org> * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include "includes.h" #include <sys/types.h> #include <limits.h> #include "crypto_api.h" #include <string.h> #include <stdarg.h> #include "log.h" #include "sshbuf.h" #define SSHKEY_INTERNAL #include "sshkey.h" #include "ssherr.h" #include "ssh.h" int ssh_ed25519_sign(const struct sshkey *key, u_char **sigp, size_t *lenp, const u_char *data, size_t datalen, u_int compat) { u_char *sig = NULL; size_t slen = 0, len; unsigned long long smlen; int r, ret; struct sshbuf *b = NULL; if (lenp != NULL) *lenp = 0; if (sigp != NULL) *sigp = NULL; if (key == NULL || sshkey_type_plain(key->type) != KEY_ED25519 || key->ed25519_sk == NULL || datalen >= INT_MAX - crypto_sign_ed25519_BYTES) return SSH_ERR_INVALID_ARGUMENT; smlen = slen = datalen + crypto_sign_ed25519_BYTES; if ((sig = malloc(slen)) == NULL) return SSH_ERR_ALLOC_FAIL; if ((ret = crypto_sign_ed25519(sig, &smlen, data, datalen, key->ed25519_sk)) != 0 || smlen <= datalen) { r = SSH_ERR_INVALID_ARGUMENT; /* XXX better error? */ goto out; } /* encode signature */ if ((b = sshbuf_new()) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } if ((r = sshbuf_put_cstring(b, "ssh-ed25519")) != 0 || (r = sshbuf_put_string(b, sig, smlen - datalen)) != 0) goto out; len = sshbuf_len(b); if (sigp != NULL) { if ((*sigp = malloc(len)) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } memcpy(*sigp, sshbuf_ptr(b), len); } if (lenp != NULL) *lenp = len; /* success */ r = 0; out: sshbuf_free(b); if (sig != NULL) { explicit_bzero(sig, slen); free(sig); } return r; } int ssh_ed25519_verify(const struct sshkey *key, const u_char *signature, size_t signaturelen, const u_char *data, size_t datalen, u_int compat) { struct sshbuf *b = NULL; char *ktype = NULL; const u_char *sigblob; u_char *sm = NULL, *m = NULL; size_t len; unsigned long long smlen = 0, mlen = 0; int r, ret; if (key == NULL || sshkey_type_plain(key->type) != KEY_ED25519 || key->ed25519_pk == NULL || datalen >= INT_MAX - crypto_sign_ed25519_BYTES) return SSH_ERR_INVALID_ARGUMENT; if ((b = sshbuf_from(signature, signaturelen)) == NULL) return SSH_ERR_ALLOC_FAIL; if ((r = sshbuf_get_cstring(b, &ktype, NULL)) != 0 || (r = sshbuf_get_string_direct(b, &sigblob, &len)) != 0) goto out; if (strcmp("ssh-ed25519", ktype) != 0) { r = SSH_ERR_KEY_TYPE_MISMATCH; goto out; } if (sshbuf_len(b) != 0) { r = SSH_ERR_UNEXPECTED_TRAILING_DATA; goto out; } if (len > crypto_sign_ed25519_BYTES) { r = SSH_ERR_INVALID_FORMAT; goto out; } if (datalen >= SIZE_MAX - len) { r = SSH_ERR_INVALID_ARGUMENT; goto out; } smlen = len + datalen; mlen = smlen; if ((sm = malloc(smlen)) == NULL || (m = malloc(mlen)) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto out; } memcpy(sm, sigblob, len); memcpy(sm+len, data, datalen); if ((ret = crypto_sign_ed25519_open(m, &mlen, sm, smlen, key->ed25519_pk)) != 0) { debug2("%s: crypto_sign_ed25519_open failed: %d", __func__, ret); } if (ret != 0 || mlen != datalen) { r = SSH_ERR_SIGNATURE_INVALID; goto out; } /* XXX compare 'm' and 'data' ? */ /* success */ r = 0; out: if (sm != NULL) { explicit_bzero(sm, smlen); free(sm); } if (m != NULL) { explicit_bzero(m, smlen); /* NB mlen may be invalid if r != 0 */ free(m); } sshbuf_free(b); free(ktype); return r; }