/* $OpenBSD: key.c,v 1.98 2011/10/18 04:58:26 djm Exp $ */ /* * read_bignum(): * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland * * As far as I am concerned, the code I have written for this software * can be used freely for any purpose. Any derived versions of this * software must be clearly marked as such, and if the derived work is * incompatible with the protocol description in the RFC file, it must be * called by a name other than "ssh" or "Secure Shell". * * * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. * Copyright (c) 2008 Alexander von Gernler. 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 <sys/param.h> #include <sys/types.h> #include <openssl/evp.h> #include <stdio.h> #include <string.h> #include "xmalloc.h" #include "key.h" #include "rsa.h" #include "uuencode.h" #include "buffer.h" #include "log.h" #include "misc.h" #include "ssh2.h" static struct KeyCert * cert_new(void) { struct KeyCert *cert; cert = xcalloc(1, sizeof(*cert)); buffer_init(&cert->certblob); buffer_init(&cert->critical); buffer_init(&cert->extensions); cert->key_id = NULL; cert->principals = NULL; cert->signature_key = NULL; return cert; } Key * key_new(int type) { Key *k; RSA *rsa; DSA *dsa; k = xcalloc(1, sizeof(*k)); k->type = type; k->ecdsa = NULL; k->ecdsa_nid = -1; k->dsa = NULL; k->rsa = NULL; k->cert = NULL; switch (k->type) { case KEY_RSA1: case KEY_RSA: case KEY_RSA_CERT_V00: case KEY_RSA_CERT: if ((rsa = RSA_new()) == NULL) fatal("key_new: RSA_new failed"); if ((rsa->n = BN_new()) == NULL) fatal("key_new: BN_new failed"); if ((rsa->e = BN_new()) == NULL) fatal("key_new: BN_new failed"); k->rsa = rsa; break; case KEY_DSA: case KEY_DSA_CERT_V00: case KEY_DSA_CERT: if ((dsa = DSA_new()) == NULL) fatal("key_new: DSA_new failed"); if ((dsa->p = BN_new()) == NULL) fatal("key_new: BN_new failed"); if ((dsa->q = BN_new()) == NULL) fatal("key_new: BN_new failed"); if ((dsa->g = BN_new()) == NULL) fatal("key_new: BN_new failed"); if ((dsa->pub_key = BN_new()) == NULL) fatal("key_new: BN_new failed"); k->dsa = dsa; break; case KEY_ECDSA: case KEY_ECDSA_CERT: /* Cannot do anything until we know the group */ break; case KEY_UNSPEC: break; default: fatal("key_new: bad key type %d", k->type); break; } if (key_is_cert(k)) k->cert = cert_new(); return k; } void key_add_private(Key *k) { switch (k->type) { case KEY_RSA1: case KEY_RSA: case KEY_RSA_CERT_V00: case KEY_RSA_CERT: if ((k->rsa->d = BN_new()) == NULL) fatal("key_new_private: BN_new failed"); if ((k->rsa->iqmp = BN_new()) == NULL) fatal("key_new_private: BN_new failed"); if ((k->rsa->q = BN_new()) == NULL) fatal("key_new_private: BN_new failed"); if ((k->rsa->p = BN_new()) == NULL) fatal("key_new_private: BN_new failed"); if ((k->rsa->dmq1 = BN_new()) == NULL) fatal("key_new_private: BN_new failed"); if ((k->rsa->dmp1 = BN_new()) == NULL) fatal("key_new_private: BN_new failed"); break; case KEY_DSA: case KEY_DSA_CERT_V00: case KEY_DSA_CERT: if ((k->dsa->priv_key = BN_new()) == NULL) fatal("key_new_private: BN_new failed"); break; case KEY_ECDSA: case KEY_ECDSA_CERT: /* Cannot do anything until we know the group */ break; case KEY_UNSPEC: break; default: break; } } Key * key_new_private(int type) { Key *k = key_new(type); key_add_private(k); return k; } static void cert_free(struct KeyCert *cert) { u_int i; buffer_free(&cert->certblob); buffer_free(&cert->critical); buffer_free(&cert->extensions); if (cert->key_id != NULL) xfree(cert->key_id); for (i = 0; i < cert->nprincipals; i++) xfree(cert->principals[i]); if (cert->principals != NULL) xfree(cert->principals); if (cert->signature_key != NULL) key_free(cert->signature_key); } void key_free(Key *k) { if (k == NULL) fatal("key_free: key is NULL"); switch (k->type) { case KEY_RSA1: case KEY_RSA: case KEY_RSA_CERT_V00: case KEY_RSA_CERT: if (k->rsa != NULL) RSA_free(k->rsa); k->rsa = NULL; break; case KEY_DSA: case KEY_DSA_CERT_V00: case KEY_DSA_CERT: if (k->dsa != NULL) DSA_free(k->dsa); k->dsa = NULL; break; case KEY_ECDSA: case KEY_ECDSA_CERT: if (k->ecdsa != NULL) EC_KEY_free(k->ecdsa); k->ecdsa = NULL; break; case KEY_UNSPEC: break; default: fatal("key_free: bad key type %d", k->type); break; } if (key_is_cert(k)) { if (k->cert != NULL) cert_free(k->cert); k->cert = NULL; } xfree(k); } static int cert_compare(struct KeyCert *a, struct KeyCert *b) { if (a == NULL && b == NULL) return 1; if (a == NULL || b == NULL) return 0; if (buffer_len(&a->certblob) != buffer_len(&b->certblob)) return 0; if (timingsafe_bcmp(buffer_ptr(&a->certblob), buffer_ptr(&b->certblob), buffer_len(&a->certblob)) != 0) return 0; return 1; } /* * Compare public portions of key only, allowing comparisons between * certificates and plain keys too. */ int key_equal_public(const Key *a, const Key *b) { BN_CTX *bnctx; if (a == NULL || b == NULL || key_type_plain(a->type) != key_type_plain(b->type)) return 0; switch (a->type) { case KEY_RSA1: case KEY_RSA_CERT_V00: case KEY_RSA_CERT: case KEY_RSA: return a->rsa != NULL && b->rsa != NULL && BN_cmp(a->rsa->e, b->rsa->e) == 0 && BN_cmp(a->rsa->n, b->rsa->n) == 0; case KEY_DSA_CERT_V00: case KEY_DSA_CERT: case KEY_DSA: return a->dsa != NULL && b->dsa != NULL && BN_cmp(a->dsa->p, b->dsa->p) == 0 && BN_cmp(a->dsa->q, b->dsa->q) == 0 && BN_cmp(a->dsa->g, b->dsa->g) == 0 && BN_cmp(a->dsa->pub_key, b->dsa->pub_key) == 0; case KEY_ECDSA_CERT: case KEY_ECDSA: if (a->ecdsa == NULL || b->ecdsa == NULL || EC_KEY_get0_public_key(a->ecdsa) == NULL || EC_KEY_get0_public_key(b->ecdsa) == NULL) return 0; if ((bnctx = BN_CTX_new()) == NULL) fatal("%s: BN_CTX_new failed", __func__); if (EC_GROUP_cmp(EC_KEY_get0_group(a->ecdsa), EC_KEY_get0_group(b->ecdsa), bnctx) != 0 || EC_POINT_cmp(EC_KEY_get0_group(a->ecdsa), EC_KEY_get0_public_key(a->ecdsa), EC_KEY_get0_public_key(b->ecdsa), bnctx) != 0) { BN_CTX_free(bnctx); return 0; } BN_CTX_free(bnctx); return 1; default: fatal("key_equal: bad key type %d", a->type); } /* NOTREACHED */ } int key_equal(const Key *a, const Key *b) { if (a == NULL || b == NULL || a->type != b->type) return 0; if (key_is_cert(a)) { if (!cert_compare(a->cert, b->cert)) return 0; } return key_equal_public(a, b); } u_char* key_fingerprint_raw(Key *k, enum fp_type dgst_type, u_int *dgst_raw_length) { const EVP_MD *md = NULL; EVP_MD_CTX ctx; u_char *blob = NULL; u_char *retval = NULL; u_int len = 0; int nlen, elen, otype; *dgst_raw_length = 0; switch (dgst_type) { case SSH_FP_MD5: md = EVP_md5(); break; case SSH_FP_SHA1: md = EVP_sha1(); break; default: fatal("key_fingerprint_raw: bad digest type %d", dgst_type); } switch (k->type) { case KEY_RSA1: nlen = BN_num_bytes(k->rsa->n); elen = BN_num_bytes(k->rsa->e); len = nlen + elen; blob = xmalloc(len); BN_bn2bin(k->rsa->n, blob); BN_bn2bin(k->rsa->e, blob + nlen); break; case KEY_DSA: case KEY_ECDSA: case KEY_RSA: key_to_blob(k, &blob, &len); break; case KEY_DSA_CERT_V00: case KEY_RSA_CERT_V00: case KEY_DSA_CERT: case KEY_ECDSA_CERT: case KEY_RSA_CERT: /* We want a fingerprint of the _key_ not of the cert */ otype = k->type; k->type = key_type_plain(k->type); key_to_blob(k, &blob, &len); k->type = otype; break; case KEY_UNSPEC: return retval; default: fatal("key_fingerprint_raw: bad key type %d", k->type); break; } if (blob != NULL) { retval = xmalloc(EVP_MAX_MD_SIZE); EVP_DigestInit(&ctx, md); EVP_DigestUpdate(&ctx, blob, len); EVP_DigestFinal(&ctx, retval, dgst_raw_length); memset(blob, 0, len); xfree(blob); } else { fatal("key_fingerprint_raw: blob is null"); } return retval; } static char * key_fingerprint_hex(u_char *dgst_raw, u_int dgst_raw_len) { char *retval; u_int i; retval = xcalloc(1, dgst_raw_len * 3 + 1); for (i = 0; i < dgst_raw_len; i++) { char hex[4]; snprintf(hex, sizeof(hex), "%02x:", dgst_raw[i]); strlcat(retval, hex, dgst_raw_len * 3 + 1); } /* Remove the trailing ':' character */ retval[(dgst_raw_len * 3) - 1] = '\0'; return retval; } static char * key_fingerprint_bubblebabble(u_char *dgst_raw, u_int dgst_raw_len) { char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' }; char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm', 'n', 'p', 'r', 's', 't', 'v', 'z', 'x' }; u_int i, j = 0, rounds, seed = 1; char *retval; rounds = (dgst_raw_len / 2) + 1; retval = xcalloc((rounds * 6), sizeof(char)); retval[j++] = 'x'; for (i = 0; i < rounds; i++) { u_int idx0, idx1, idx2, idx3, idx4; if ((i + 1 < rounds) || (dgst_raw_len % 2 != 0)) { idx0 = (((((u_int)(dgst_raw[2 * i])) >> 6) & 3) + seed) % 6; idx1 = (((u_int)(dgst_raw[2 * i])) >> 2) & 15; idx2 = ((((u_int)(dgst_raw[2 * i])) & 3) + (seed / 6)) % 6; retval[j++] = vowels[idx0]; retval[j++] = consonants[idx1]; retval[j++] = vowels[idx2]; if ((i + 1) < rounds) { idx3 = (((u_int)(dgst_raw[(2 * i) + 1])) >> 4) & 15; idx4 = (((u_int)(dgst_raw[(2 * i) + 1]))) & 15; retval[j++] = consonants[idx3]; retval[j++] = '-'; retval[j++] = consonants[idx4]; seed = ((seed * 5) + ((((u_int)(dgst_raw[2 * i])) * 7) + ((u_int)(dgst_raw[(2 * i) + 1])))) % 36; } } else { idx0 = seed % 6; idx1 = 16; idx2 = seed / 6; retval[j++] = vowels[idx0]; retval[j++] = consonants[idx1]; retval[j++] = vowels[idx2]; } } retval[j++] = 'x'; retval[j++] = '\0'; return retval; } /* * Draw an ASCII-Art representing the fingerprint so human brain can * profit from its built-in pattern recognition ability. * This technique is called "random art" and can be found in some * scientific publications like this original paper: * * "Hash Visualization: a New Technique to improve Real-World Security", * Perrig A. and Song D., 1999, International Workshop on Cryptographic * Techniques and E-Commerce (CrypTEC '99) * sparrow.ece.cmu.edu/~adrian/projects/validation/validation.pdf * * The subject came up in a talk by Dan Kaminsky, too. * * If you see the picture is different, the key is different. * If the picture looks the same, you still know nothing. * * The algorithm used here is a worm crawling over a discrete plane, * leaving a trace (augmenting the field) everywhere it goes. * Movement is taken from dgst_raw 2bit-wise. Bumping into walls * makes the respective movement vector be ignored for this turn. * Graphs are not unambiguous, because circles in graphs can be * walked in either direction. */ /* * Field sizes for the random art. Have to be odd, so the starting point * can be in the exact middle of the picture, and FLDBASE should be >=8 . * Else pictures would be too dense, and drawing the frame would * fail, too, because the key type would not fit in anymore. */ #define FLDBASE 8 #define FLDSIZE_Y (FLDBASE + 1) #define FLDSIZE_X (FLDBASE * 2 + 1) static char * key_fingerprint_randomart(u_char *dgst_raw, u_int dgst_raw_len, const Key *k) { /* * Chars to be used after each other every time the worm * intersects with itself. Matter of taste. */ char *augmentation_string = " .o+=*BOX@%&#/^SE"; char *retval, *p; u_char field[FLDSIZE_X][FLDSIZE_Y]; u_int i, b; int x, y; size_t len = strlen(augmentation_string) - 1; retval = xcalloc(1, (FLDSIZE_X + 3) * (FLDSIZE_Y + 2)); /* initialize field */ memset(field, 0, FLDSIZE_X * FLDSIZE_Y * sizeof(char)); x = FLDSIZE_X / 2; y = FLDSIZE_Y / 2; /* process raw key */ for (i = 0; i < dgst_raw_len; i++) { int input; /* each byte conveys four 2-bit move commands */ input = dgst_raw[i]; for (b = 0; b < 4; b++) { /* evaluate 2 bit, rest is shifted later */ x += (input & 0x1) ? 1 : -1; y += (input & 0x2) ? 1 : -1; /* assure we are still in bounds */ x = MAX(x, 0); y = MAX(y, 0); x = MIN(x, FLDSIZE_X - 1); y = MIN(y, FLDSIZE_Y - 1); /* augment the field */ if (field[x][y] < len - 2) field[x][y]++; input = input >> 2; } } /* mark starting point and end point*/ field[FLDSIZE_X / 2][FLDSIZE_Y / 2] = len - 1; field[x][y] = len; /* fill in retval */ snprintf(retval, FLDSIZE_X, "+--[%4s %4u]", key_type(k), key_size(k)); p = strchr(retval, '\0'); /* output upper border */ for (i = p - retval - 1; i < FLDSIZE_X; i++) *p++ = '-'; *p++ = '+'; *p++ = '\n'; /* output content */ for (y = 0; y < FLDSIZE_Y; y++) { *p++ = '|'; for (x = 0; x < FLDSIZE_X; x++) *p++ = augmentation_string[MIN(field[x][y], len)]; *p++ = '|'; *p++ = '\n'; } /* output lower border */ *p++ = '+'; for (i = 0; i < FLDSIZE_X; i++) *p++ = '-'; *p++ = '+'; return retval; } char * key_fingerprint(Key *k, enum fp_type dgst_type, enum fp_rep dgst_rep) { char *retval = NULL; u_char *dgst_raw; u_int dgst_raw_len; dgst_raw = key_fingerprint_raw(k, dgst_type, &dgst_raw_len); if (!dgst_raw) fatal("key_fingerprint: null from key_fingerprint_raw()"); switch (dgst_rep) { case SSH_FP_HEX: retval = key_fingerprint_hex(dgst_raw, dgst_raw_len); break; case SSH_FP_BUBBLEBABBLE: retval = key_fingerprint_bubblebabble(dgst_raw, dgst_raw_len); break; case SSH_FP_RANDOMART: retval = key_fingerprint_randomart(dgst_raw, dgst_raw_len, k); break; default: fatal("key_fingerprint: bad digest representation %d", dgst_rep); break; } memset(dgst_raw, 0, dgst_raw_len); xfree(dgst_raw); return retval; } /* * Reads a multiple-precision integer in decimal from the buffer, and advances * the pointer. The integer must already be initialized. This function is * permitted to modify the buffer. This leaves *cpp to point just beyond the * last processed (and maybe modified) character. Note that this may modify * the buffer containing the number. */ static int read_bignum(char **cpp, BIGNUM * value) { char *cp = *cpp; int old; /* Skip any leading whitespace. */ for (; *cp == ' ' || *cp == '\t'; cp++) ; /* Check that it begins with a decimal digit. */ if (*cp < '0' || *cp > '9') return 0; /* Save starting position. */ *cpp = cp; /* Move forward until all decimal digits skipped. */ for (; *cp >= '0' && *cp <= '9'; cp++) ; /* Save the old terminating character, and replace it by \0. */ old = *cp; *cp = 0; /* Parse the number. */ if (BN_dec2bn(&value, *cpp) == 0) return 0; /* Restore old terminating character. */ *cp = old; /* Move beyond the number and return success. */ *cpp = cp; return 1; } static int write_bignum(FILE *f, BIGNUM *num) { char *buf = BN_bn2dec(num); if (buf == NULL) { error("write_bignum: BN_bn2dec() failed"); return 0; } fprintf(f, " %s", buf); OPENSSL_free(buf); return 1; } /* returns 1 ok, -1 error */ int key_read(Key *ret, char **cpp) { Key *k; int success = -1; char *cp, *space; int len, n, type, curve_nid = -1; u_int bits; u_char *blob; cp = *cpp; switch (ret->type) { case KEY_RSA1: /* Get number of bits. */ if (*cp < '0' || *cp > '9') return -1; /* Bad bit count... */ for (bits = 0; *cp >= '0' && *cp <= '9'; cp++) bits = 10 * bits + *cp - '0'; if (bits == 0) return -1; *cpp = cp; /* Get public exponent, public modulus. */ if (!read_bignum(cpp, ret->rsa->e)) return -1; if (!read_bignum(cpp, ret->rsa->n)) return -1; /* validate the claimed number of bits */ if ((u_int)BN_num_bits(ret->rsa->n) != bits) { verbose("key_read: claimed key size %d does not match " "actual %d", bits, BN_num_bits(ret->rsa->n)); return -1; } success = 1; break; case KEY_UNSPEC: case KEY_RSA: case KEY_DSA: case KEY_ECDSA: case KEY_DSA_CERT_V00: case KEY_RSA_CERT_V00: case KEY_DSA_CERT: case KEY_ECDSA_CERT: case KEY_RSA_CERT: space = strchr(cp, ' '); if (space == NULL) { debug3("key_read: missing whitespace"); return -1; } *space = '\0'; type = key_type_from_name(cp); if (key_type_plain(type) == KEY_ECDSA && (curve_nid = key_ecdsa_nid_from_name(cp)) == -1) { debug("key_read: invalid curve"); return -1; } *space = ' '; if (type == KEY_UNSPEC) { debug3("key_read: missing keytype"); return -1; } cp = space+1; if (*cp == '\0') { debug3("key_read: short string"); return -1; } if (ret->type == KEY_UNSPEC) { ret->type = type; } else if (ret->type != type) { /* is a key, but different type */ debug3("key_read: type mismatch"); return -1; } len = 2*strlen(cp); blob = xmalloc(len); n = uudecode(cp, blob, len); if (n < 0) { error("key_read: uudecode %s failed", cp); xfree(blob); return -1; } k = key_from_blob(blob, (u_int)n); xfree(blob); if (k == NULL) { error("key_read: key_from_blob %s failed", cp); return -1; } if (k->type != type) { error("key_read: type mismatch: encoding error"); key_free(k); return -1; } if (key_type_plain(type) == KEY_ECDSA && curve_nid != k->ecdsa_nid) { error("key_read: type mismatch: EC curve mismatch"); key_free(k); return -1; } /*XXXX*/ if (key_is_cert(ret)) { if (!key_is_cert(k)) { error("key_read: loaded key is not a cert"); key_free(k); return -1; } if (ret->cert != NULL) cert_free(ret->cert); ret->cert = k->cert; k->cert = NULL; } if (key_type_plain(ret->type) == KEY_RSA) { if (ret->rsa != NULL) RSA_free(ret->rsa); ret->rsa = k->rsa; k->rsa = NULL; #ifdef DEBUG_PK RSA_print_fp(stderr, ret->rsa, 8); #endif } if (key_type_plain(ret->type) == KEY_DSA) { if (ret->dsa != NULL) DSA_free(ret->dsa); ret->dsa = k->dsa; k->dsa = NULL; #ifdef DEBUG_PK DSA_print_fp(stderr, ret->dsa, 8); #endif } if (key_type_plain(ret->type) == KEY_ECDSA) { if (ret->ecdsa != NULL) EC_KEY_free(ret->ecdsa); ret->ecdsa = k->ecdsa; ret->ecdsa_nid = k->ecdsa_nid; k->ecdsa = NULL; k->ecdsa_nid = -1; #ifdef DEBUG_PK key_dump_ec_key(ret->ecdsa); #endif } success = 1; /*XXXX*/ key_free(k); if (success != 1) break; /* advance cp: skip whitespace and data */ while (*cp == ' ' || *cp == '\t') cp++; while (*cp != '\0' && *cp != ' ' && *cp != '\t') cp++; *cpp = cp; break; default: fatal("key_read: bad key type: %d", ret->type); break; } return success; } int key_write(const Key *key, FILE *f) { int n, success = 0; u_int len, bits = 0; u_char *blob; char *uu; if (key_is_cert(key)) { if (key->cert == NULL) { error("%s: no cert data", __func__); return 0; } if (buffer_len(&key->cert->certblob) == 0) { error("%s: no signed certificate blob", __func__); return 0; } } switch (key->type) { case KEY_RSA1: if (key->rsa == NULL) return 0; /* size of modulus 'n' */ bits = BN_num_bits(key->rsa->n); fprintf(f, "%u", bits); if (write_bignum(f, key->rsa->e) && write_bignum(f, key->rsa->n)) return 1; error("key_write: failed for RSA key"); return 0; case KEY_DSA: case KEY_DSA_CERT_V00: case KEY_DSA_CERT: if (key->dsa == NULL) return 0; break; case KEY_ECDSA: case KEY_ECDSA_CERT: if (key->ecdsa == NULL) return 0; break; case KEY_RSA: case KEY_RSA_CERT_V00: case KEY_RSA_CERT: if (key->rsa == NULL) return 0; break; default: return 0; } key_to_blob(key, &blob, &len); uu = xmalloc(2*len); n = uuencode(blob, len, uu, 2*len); if (n > 0) { fprintf(f, "%s %s", key_ssh_name(key), uu); success = 1; } xfree(blob); xfree(uu); return success; } const char * key_type(const Key *k) { switch (k->type) { case KEY_RSA1: return "RSA1"; case KEY_RSA: return "RSA"; case KEY_DSA: return "DSA"; case KEY_ECDSA: return "ECDSA"; case KEY_RSA_CERT_V00: return "RSA-CERT-V00"; case KEY_DSA_CERT_V00: return "DSA-CERT-V00"; case KEY_RSA_CERT: return "RSA-CERT"; case KEY_DSA_CERT: return "DSA-CERT"; case KEY_ECDSA_CERT: return "ECDSA-CERT"; } return "unknown"; } const char * key_cert_type(const Key *k) { switch (k->cert->type) { case SSH2_CERT_TYPE_USER: return "user"; case SSH2_CERT_TYPE_HOST: return "host"; default: return "unknown"; } } static const char * key_ssh_name_from_type_nid(int type, int nid) { switch (type) { case KEY_RSA: return "ssh-rsa"; case KEY_DSA: return "ssh-dss"; case KEY_RSA_CERT_V00: return "ssh-rsa-cert-v00@openssh.com"; case KEY_DSA_CERT_V00: return "ssh-dss-cert-v00@openssh.com"; case KEY_RSA_CERT: return "ssh-rsa-cert-v01@openssh.com"; case KEY_DSA_CERT: return "ssh-dss-cert-v01@openssh.com"; case KEY_ECDSA: switch (nid) { case NID_X9_62_prime256v1: return "ecdsa-sha2-nistp256"; case NID_secp384r1: return "ecdsa-sha2-nistp384"; case NID_secp521r1: return "ecdsa-sha2-nistp521"; default: break; } break; case KEY_ECDSA_CERT: switch (nid) { case NID_X9_62_prime256v1: return "ecdsa-sha2-nistp256-cert-v01@openssh.com"; case NID_secp384r1: return "ecdsa-sha2-nistp384-cert-v01@openssh.com"; case NID_secp521r1: return "ecdsa-sha2-nistp521-cert-v01@openssh.com"; default: break; } break; } return "ssh-unknown"; } const char * key_ssh_name(const Key *k) { return key_ssh_name_from_type_nid(k->type, k->ecdsa_nid); } const char * key_ssh_name_plain(const Key *k) { return key_ssh_name_from_type_nid(key_type_plain(k->type), k->ecdsa_nid); } u_int key_size(const Key *k) { switch (k->type) { case KEY_RSA1: case KEY_RSA: case KEY_RSA_CERT_V00: case KEY_RSA_CERT: return BN_num_bits(k->rsa->n); case KEY_DSA: case KEY_DSA_CERT_V00: case KEY_DSA_CERT: return BN_num_bits(k->dsa->p); case KEY_ECDSA: case KEY_ECDSA_CERT: return key_curve_nid_to_bits(k->ecdsa_nid); } return 0; } static RSA * rsa_generate_private_key(u_int bits) { RSA *private = RSA_new(); BIGNUM *f4 = BN_new(); if (private == NULL) fatal("%s: RSA_new failed", __func__); if (f4 == NULL) fatal("%s: BN_new failed", __func__); if (!BN_set_word(f4, RSA_F4)) fatal("%s: BN_new failed", __func__); if (!RSA_generate_key_ex(private, bits, f4, NULL)) fatal("%s: key generation failed.", __func__); BN_free(f4); return private; } static DSA* dsa_generate_private_key(u_int bits) { DSA *private = DSA_new(); if (private == NULL) fatal("%s: DSA_new failed", __func__); if (!DSA_generate_parameters_ex(private, bits, NULL, 0, NULL, NULL, NULL)) fatal("%s: DSA_generate_parameters failed", __func__); if (!DSA_generate_key(private)) fatal("%s: DSA_generate_key failed.", __func__); return private; } int key_ecdsa_bits_to_nid(int bits) { switch (bits) { case 256: return NID_X9_62_prime256v1; case 384: return NID_secp384r1; case 521: return NID_secp521r1; default: return -1; } } int key_ecdsa_key_to_nid(EC_KEY *k) { EC_GROUP *eg; int nids[] = { NID_X9_62_prime256v1, NID_secp384r1, NID_secp521r1, -1 }; int nid; u_int i; BN_CTX *bnctx; const EC_GROUP *g = EC_KEY_get0_group(k); /* * The group may be stored in a ASN.1 encoded private key in one of two * ways: as a "named group", which is reconstituted by ASN.1 object ID * or explicit group parameters encoded into the key blob. Only the * "named group" case sets the group NID for us, but we can figure * it out for the other case by comparing against all the groups that * are supported. */ if ((nid = EC_GROUP_get_curve_name(g)) > 0) return nid; if ((bnctx = BN_CTX_new()) == NULL) fatal("%s: BN_CTX_new() failed", __func__); for (i = 0; nids[i] != -1; i++) { if ((eg = EC_GROUP_new_by_curve_name(nids[i])) == NULL) fatal("%s: EC_GROUP_new_by_curve_name failed", __func__); if (EC_GROUP_cmp(g, eg, bnctx) == 0) break; EC_GROUP_free(eg); } BN_CTX_free(bnctx); debug3("%s: nid = %d", __func__, nids[i]); if (nids[i] != -1) { /* Use the group with the NID attached */ EC_GROUP_set_asn1_flag(eg, OPENSSL_EC_NAMED_CURVE); if (EC_KEY_set_group(k, eg) != 1) fatal("%s: EC_KEY_set_group", __func__); } return nids[i]; } static EC_KEY* ecdsa_generate_private_key(u_int bits, int *nid) { EC_KEY *private; if ((*nid = key_ecdsa_bits_to_nid(bits)) == -1) fatal("%s: invalid key length", __func__); if ((private = EC_KEY_new_by_curve_name(*nid)) == NULL) fatal("%s: EC_KEY_new_by_curve_name failed", __func__); if (EC_KEY_generate_key(private) != 1) fatal("%s: EC_KEY_generate_key failed", __func__); EC_KEY_set_asn1_flag(private, OPENSSL_EC_NAMED_CURVE); return private; } Key * key_generate(int type, u_int bits) { Key *k = key_new(KEY_UNSPEC); switch (type) { case KEY_DSA: k->dsa = dsa_generate_private_key(bits); break; case KEY_ECDSA: k->ecdsa = ecdsa_generate_private_key(bits, &k->ecdsa_nid); break; case KEY_RSA: case KEY_RSA1: k->rsa = rsa_generate_private_key(bits); break; case KEY_RSA_CERT_V00: case KEY_DSA_CERT_V00: case KEY_RSA_CERT: case KEY_DSA_CERT: fatal("key_generate: cert keys cannot be generated directly"); default: fatal("key_generate: unknown type %d", type); } k->type = type; return k; } void key_cert_copy(const Key *from_key, struct Key *to_key) { u_int i; const struct KeyCert *from; struct KeyCert *to; if (to_key->cert != NULL) { cert_free(to_key->cert); to_key->cert = NULL; } if ((from = from_key->cert) == NULL) return; to = to_key->cert = cert_new(); buffer_append(&to->certblob, buffer_ptr(&from->certblob), buffer_len(&from->certblob)); buffer_append(&to->critical, buffer_ptr(&from->critical), buffer_len(&from->critical)); buffer_append(&to->extensions, buffer_ptr(&from->extensions), buffer_len(&from->extensions)); to->serial = from->serial; to->type = from->type; to->key_id = from->key_id == NULL ? NULL : xstrdup(from->key_id); to->valid_after = from->valid_after; to->valid_before = from->valid_before; to->signature_key = from->signature_key == NULL ? NULL : key_from_private(from->signature_key); to->nprincipals = from->nprincipals; if (to->nprincipals > CERT_MAX_PRINCIPALS) fatal("%s: nprincipals (%u) > CERT_MAX_PRINCIPALS (%u)", __func__, to->nprincipals, CERT_MAX_PRINCIPALS); if (to->nprincipals > 0) { to->principals = xcalloc(from->nprincipals, sizeof(*to->principals)); for (i = 0; i < to->nprincipals; i++) to->principals[i] = xstrdup(from->principals[i]); } } Key * key_from_private(const Key *k) { Key *n = NULL; switch (k->type) { case KEY_DSA: case KEY_DSA_CERT_V00: case KEY_DSA_CERT: n = key_new(k->type); if ((BN_copy(n->dsa->p, k->dsa->p) == NULL) || (BN_copy(n->dsa->q, k->dsa->q) == NULL) || (BN_copy(n->dsa->g, k->dsa->g) == NULL) || (BN_copy(n->dsa->pub_key, k->dsa->pub_key) == NULL)) fatal("key_from_private: BN_copy failed"); break; case KEY_ECDSA: case KEY_ECDSA_CERT: n = key_new(k->type); n->ecdsa_nid = k->ecdsa_nid; if ((n->ecdsa = EC_KEY_new_by_curve_name(k->ecdsa_nid)) == NULL) fatal("%s: EC_KEY_new_by_curve_name failed", __func__); if (EC_KEY_set_public_key(n->ecdsa, EC_KEY_get0_public_key(k->ecdsa)) != 1) fatal("%s: EC_KEY_set_public_key failed", __func__); break; case KEY_RSA: case KEY_RSA1: case KEY_RSA_CERT_V00: case KEY_RSA_CERT: n = key_new(k->type); if ((BN_copy(n->rsa->n, k->rsa->n) == NULL) || (BN_copy(n->rsa->e, k->rsa->e) == NULL)) fatal("key_from_private: BN_copy failed"); break; default: fatal("key_from_private: unknown type %d", k->type); break; } if (key_is_cert(k)) key_cert_copy(k, n); return n; } int key_type_from_name(char *name) { if (strcmp(name, "rsa1") == 0) { return KEY_RSA1; } else if (strcmp(name, "rsa") == 0) { return KEY_RSA; } else if (strcmp(name, "dsa") == 0) { return KEY_DSA; } else if (strcmp(name, "ssh-rsa") == 0) { return KEY_RSA; } else if (strcmp(name, "ssh-dss") == 0) { return KEY_DSA; } else if (strcmp(name, "ecdsa") == 0 || strcmp(name, "ecdsa-sha2-nistp256") == 0 || strcmp(name, "ecdsa-sha2-nistp384") == 0 || strcmp(name, "ecdsa-sha2-nistp521") == 0) { return KEY_ECDSA; } else if (strcmp(name, "ssh-rsa-cert-v00@openssh.com") == 0) { return KEY_RSA_CERT_V00; } else if (strcmp(name, "ssh-dss-cert-v00@openssh.com") == 0) { return KEY_DSA_CERT_V00; } else if (strcmp(name, "ssh-rsa-cert-v01@openssh.com") == 0) { return KEY_RSA_CERT; } else if (strcmp(name, "ssh-dss-cert-v01@openssh.com") == 0) { return KEY_DSA_CERT; } else if (strcmp(name, "ecdsa-sha2-nistp256-cert-v01@openssh.com") == 0 || strcmp(name, "ecdsa-sha2-nistp384-cert-v01@openssh.com") == 0 || strcmp(name, "ecdsa-sha2-nistp521-cert-v01@openssh.com") == 0) return KEY_ECDSA_CERT; debug2("key_type_from_name: unknown key type '%s'", name); return KEY_UNSPEC; } int key_ecdsa_nid_from_name(const char *name) { if (strcmp(name, "ecdsa-sha2-nistp256") == 0 || strcmp(name, "ecdsa-sha2-nistp256-cert-v01@openssh.com") == 0) return NID_X9_62_prime256v1; if (strcmp(name, "ecdsa-sha2-nistp384") == 0 || strcmp(name, "ecdsa-sha2-nistp384-cert-v01@openssh.com") == 0) return NID_secp384r1; if (strcmp(name, "ecdsa-sha2-nistp521") == 0 || strcmp(name, "ecdsa-sha2-nistp521-cert-v01@openssh.com") == 0) return NID_secp521r1; debug2("%s: unknown/non-ECDSA key type '%s'", __func__, name); return -1; } int key_names_valid2(const char *names) { char *s, *cp, *p; if (names == NULL || strcmp(names, "") == 0) return 0; s = cp = xstrdup(names); for ((p = strsep(&cp, ",")); p && *p != '\0'; (p = strsep(&cp, ","))) { switch (key_type_from_name(p)) { case KEY_RSA1: case KEY_UNSPEC: xfree(s); return 0; } } debug3("key names ok: [%s]", names); xfree(s); return 1; } static int cert_parse(Buffer *b, Key *key, const u_char *blob, u_int blen) { u_char *principals, *critical, *exts, *sig_key, *sig; u_int signed_len, plen, clen, sklen, slen, kidlen, elen; Buffer tmp; char *principal; int ret = -1; int v00 = key->type == KEY_DSA_CERT_V00 || key->type == KEY_RSA_CERT_V00; buffer_init(&tmp); /* Copy the entire key blob for verification and later serialisation */ buffer_append(&key->cert->certblob, blob, blen); elen = 0; /* Not touched for v00 certs */ principals = exts = critical = sig_key = sig = NULL; if ((!v00 && buffer_get_int64_ret(&key->cert->serial, b) != 0) || buffer_get_int_ret(&key->cert->type, b) != 0 || (key->cert->key_id = buffer_get_cstring_ret(b, &kidlen)) == NULL || (principals = buffer_get_string_ret(b, &plen)) == NULL || buffer_get_int64_ret(&key->cert->valid_after, b) != 0 || buffer_get_int64_ret(&key->cert->valid_before, b) != 0 || (critical = buffer_get_string_ret(b, &clen)) == NULL || (!v00 && (exts = buffer_get_string_ret(b, &elen)) == NULL) || (v00 && buffer_get_string_ptr_ret(b, NULL) == NULL) || /* nonce */ buffer_get_string_ptr_ret(b, NULL) == NULL || /* reserved */ (sig_key = buffer_get_string_ret(b, &sklen)) == NULL) { error("%s: parse error", __func__); goto out; } /* Signature is left in the buffer so we can calculate this length */ signed_len = buffer_len(&key->cert->certblob) - buffer_len(b); if ((sig = buffer_get_string_ret(b, &slen)) == NULL) { error("%s: parse error", __func__); goto out; } if (key->cert->type != SSH2_CERT_TYPE_USER && key->cert->type != SSH2_CERT_TYPE_HOST) { error("Unknown certificate type %u", key->cert->type); goto out; } buffer_append(&tmp, principals, plen); while (buffer_len(&tmp) > 0) { if (key->cert->nprincipals >= CERT_MAX_PRINCIPALS) { error("%s: Too many principals", __func__); goto out; } if ((principal = buffer_get_cstring_ret(&tmp, &plen)) == NULL) { error("%s: Principals data invalid", __func__); goto out; } key->cert->principals = xrealloc(key->cert->principals, key->cert->nprincipals + 1, sizeof(*key->cert->principals)); key->cert->principals[key->cert->nprincipals++] = principal; } buffer_clear(&tmp); buffer_append(&key->cert->critical, critical, clen); buffer_append(&tmp, critical, clen); /* validate structure */ while (buffer_len(&tmp) != 0) { if (buffer_get_string_ptr_ret(&tmp, NULL) == NULL || buffer_get_string_ptr_ret(&tmp, NULL) == NULL) { error("%s: critical option data invalid", __func__); goto out; } } buffer_clear(&tmp); buffer_append(&key->cert->extensions, exts, elen); buffer_append(&tmp, exts, elen); /* validate structure */ while (buffer_len(&tmp) != 0) { if (buffer_get_string_ptr_ret(&tmp, NULL) == NULL || buffer_get_string_ptr_ret(&tmp, NULL) == NULL) { error("%s: extension data invalid", __func__); goto out; } } buffer_clear(&tmp); if ((key->cert->signature_key = key_from_blob(sig_key, sklen)) == NULL) { error("%s: Signature key invalid", __func__); goto out; } if (key->cert->signature_key->type != KEY_RSA && key->cert->signature_key->type != KEY_DSA && key->cert->signature_key->type != KEY_ECDSA) { error("%s: Invalid signature key type %s (%d)", __func__, key_type(key->cert->signature_key), key->cert->signature_key->type); goto out; } switch (key_verify(key->cert->signature_key, sig, slen, buffer_ptr(&key->cert->certblob), signed_len)) { case 1: ret = 0; break; /* Good signature */ case 0: error("%s: Invalid signature on certificate", __func__); goto out; case -1: error("%s: Certificate signature verification failed", __func__); goto out; } out: buffer_free(&tmp); if (principals != NULL) xfree(principals); if (critical != NULL) xfree(critical); if (exts != NULL) xfree(exts); if (sig_key != NULL) xfree(sig_key); if (sig != NULL) xfree(sig); return ret; } Key * key_from_blob(const u_char *blob, u_int blen) { Buffer b; int rlen, type, nid = -1; char *ktype = NULL, *curve = NULL; Key *key = NULL; EC_POINT *q = NULL; #ifdef DEBUG_PK dump_base64(stderr, blob, blen); #endif buffer_init(&b); buffer_append(&b, blob, blen); if ((ktype = buffer_get_cstring_ret(&b, NULL)) == NULL) { error("key_from_blob: can't read key type"); goto out; } type = key_type_from_name(ktype); if (key_type_plain(type) == KEY_ECDSA) nid = key_ecdsa_nid_from_name(ktype); switch (type) { case KEY_RSA_CERT: (void)buffer_get_string_ptr_ret(&b, NULL); /* Skip nonce */ /* FALLTHROUGH */ case KEY_RSA: case KEY_RSA_CERT_V00: key = key_new(type); if (buffer_get_bignum2_ret(&b, key->rsa->e) == -1 || buffer_get_bignum2_ret(&b, key->rsa->n) == -1) { error("key_from_blob: can't read rsa key"); badkey: key_free(key); key = NULL; goto out; } #ifdef DEBUG_PK RSA_print_fp(stderr, key->rsa, 8); #endif break; case KEY_DSA_CERT: (void)buffer_get_string_ptr_ret(&b, NULL); /* Skip nonce */ /* FALLTHROUGH */ case KEY_DSA: case KEY_DSA_CERT_V00: key = key_new(type); if (buffer_get_bignum2_ret(&b, key->dsa->p) == -1 || buffer_get_bignum2_ret(&b, key->dsa->q) == -1 || buffer_get_bignum2_ret(&b, key->dsa->g) == -1 || buffer_get_bignum2_ret(&b, key->dsa->pub_key) == -1) { error("key_from_blob: can't read dsa key"); goto badkey; } #ifdef DEBUG_PK DSA_print_fp(stderr, key->dsa, 8); #endif break; case KEY_ECDSA_CERT: (void)buffer_get_string_ptr_ret(&b, NULL); /* Skip nonce */ /* FALLTHROUGH */ case KEY_ECDSA: key = key_new(type); key->ecdsa_nid = nid; if ((curve = buffer_get_string_ret(&b, NULL)) == NULL) { error("key_from_blob: can't read ecdsa curve"); goto badkey; } if (key->ecdsa_nid != key_curve_name_to_nid(curve)) { error("key_from_blob: ecdsa curve doesn't match type"); goto badkey; } if (key->ecdsa != NULL) EC_KEY_free(key->ecdsa); if ((key->ecdsa = EC_KEY_new_by_curve_name(key->ecdsa_nid)) == NULL) fatal("key_from_blob: EC_KEY_new_by_curve_name failed"); if ((q = EC_POINT_new(EC_KEY_get0_group(key->ecdsa))) == NULL) fatal("key_from_blob: EC_POINT_new failed"); if (buffer_get_ecpoint_ret(&b, EC_KEY_get0_group(key->ecdsa), q) == -1) { error("key_from_blob: can't read ecdsa key point"); goto badkey; } if (key_ec_validate_public(EC_KEY_get0_group(key->ecdsa), q) != 0) goto badkey; if (EC_KEY_set_public_key(key->ecdsa, q) != 1) fatal("key_from_blob: EC_KEY_set_public_key failed"); #ifdef DEBUG_PK key_dump_ec_point(EC_KEY_get0_group(key->ecdsa), q); #endif break; case KEY_UNSPEC: key = key_new(type); break; default: error("key_from_blob: cannot handle type %s", ktype); goto out; } if (key_is_cert(key) && cert_parse(&b, key, blob, blen) == -1) { error("key_from_blob: can't parse cert data"); goto badkey; } rlen = buffer_len(&b); if (key != NULL && rlen != 0) error("key_from_blob: remaining bytes in key blob %d", rlen); out: if (ktype != NULL) xfree(ktype); if (curve != NULL) xfree(curve); if (q != NULL) EC_POINT_free(q); buffer_free(&b); return key; } int key_to_blob(const Key *key, u_char **blobp, u_int *lenp) { Buffer b; int len; if (key == NULL) { error("key_to_blob: key == NULL"); return 0; } buffer_init(&b); switch (key->type) { case KEY_DSA_CERT_V00: case KEY_RSA_CERT_V00: case KEY_DSA_CERT: case KEY_ECDSA_CERT: case KEY_RSA_CERT: /* Use the existing blob */ buffer_append(&b, buffer_ptr(&key->cert->certblob), buffer_len(&key->cert->certblob)); break; case KEY_DSA: buffer_put_cstring(&b, key_ssh_name(key)); buffer_put_bignum2(&b, key->dsa->p); buffer_put_bignum2(&b, key->dsa->q); buffer_put_bignum2(&b, key->dsa->g); buffer_put_bignum2(&b, key->dsa->pub_key); break; case KEY_ECDSA: buffer_put_cstring(&b, key_ssh_name(key)); buffer_put_cstring(&b, key_curve_nid_to_name(key->ecdsa_nid)); buffer_put_ecpoint(&b, EC_KEY_get0_group(key->ecdsa), EC_KEY_get0_public_key(key->ecdsa)); break; case KEY_RSA: buffer_put_cstring(&b, key_ssh_name(key)); buffer_put_bignum2(&b, key->rsa->e); buffer_put_bignum2(&b, key->rsa->n); break; default: error("key_to_blob: unsupported key type %d", key->type); buffer_free(&b); return 0; } len = buffer_len(&b); if (lenp != NULL) *lenp = len; if (blobp != NULL) { *blobp = xmalloc(len); memcpy(*blobp, buffer_ptr(&b), len); } memset(buffer_ptr(&b), 0, len); buffer_free(&b); return len; } int key_sign( const Key *key, u_char **sigp, u_int *lenp, const u_char *data, u_int datalen) { switch (key->type) { case KEY_DSA_CERT_V00: case KEY_DSA_CERT: case KEY_DSA: return ssh_dss_sign(key, sigp, lenp, data, datalen); case KEY_ECDSA_CERT: case KEY_ECDSA: return ssh_ecdsa_sign(key, sigp, lenp, data, datalen); case KEY_RSA_CERT_V00: case KEY_RSA_CERT: case KEY_RSA: return ssh_rsa_sign(key, sigp, lenp, data, datalen); default: error("key_sign: invalid key type %d", key->type); return -1; } } /* * key_verify returns 1 for a correct signature, 0 for an incorrect signature * and -1 on error. */ int key_verify( const Key *key, const u_char *signature, u_int signaturelen, const u_char *data, u_int datalen) { if (signaturelen == 0) return -1; switch (key->type) { case KEY_DSA_CERT_V00: case KEY_DSA_CERT: case KEY_DSA: return ssh_dss_verify(key, signature, signaturelen, data, datalen); case KEY_ECDSA_CERT: case KEY_ECDSA: return ssh_ecdsa_verify(key, signature, signaturelen, data, datalen); case KEY_RSA_CERT_V00: case KEY_RSA_CERT: case KEY_RSA: return ssh_rsa_verify(key, signature, signaturelen, data, datalen); default: error("key_verify: invalid key type %d", key->type); return -1; } } /* Converts a private to a public key */ Key * key_demote(const Key *k) { Key *pk; pk = xcalloc(1, sizeof(*pk)); pk->type = k->type; pk->flags = k->flags; pk->ecdsa_nid = k->ecdsa_nid; pk->dsa = NULL; pk->ecdsa = NULL; pk->rsa = NULL; switch (k->type) { case KEY_RSA_CERT_V00: case KEY_RSA_CERT: key_cert_copy(k, pk); /* FALLTHROUGH */ case KEY_RSA1: case KEY_RSA: if ((pk->rsa = RSA_new()) == NULL) fatal("key_demote: RSA_new failed"); if ((pk->rsa->e = BN_dup(k->rsa->e)) == NULL) fatal("key_demote: BN_dup failed"); if ((pk->rsa->n = BN_dup(k->rsa->n)) == NULL) fatal("key_demote: BN_dup failed"); break; case KEY_DSA_CERT_V00: case KEY_DSA_CERT: key_cert_copy(k, pk); /* FALLTHROUGH */ case KEY_DSA: if ((pk->dsa = DSA_new()) == NULL) fatal("key_demote: DSA_new failed"); if ((pk->dsa->p = BN_dup(k->dsa->p)) == NULL) fatal("key_demote: BN_dup failed"); if ((pk->dsa->q = BN_dup(k->dsa->q)) == NULL) fatal("key_demote: BN_dup failed"); if ((pk->dsa->g = BN_dup(k->dsa->g)) == NULL) fatal("key_demote: BN_dup failed"); if ((pk->dsa->pub_key = BN_dup(k->dsa->pub_key)) == NULL) fatal("key_demote: BN_dup failed"); break; case KEY_ECDSA_CERT: key_cert_copy(k, pk); /* FALLTHROUGH */ case KEY_ECDSA: if ((pk->ecdsa = EC_KEY_new_by_curve_name(pk->ecdsa_nid)) == NULL) fatal("key_demote: EC_KEY_new_by_curve_name failed"); if (EC_KEY_set_public_key(pk->ecdsa, EC_KEY_get0_public_key(k->ecdsa)) != 1) fatal("key_demote: EC_KEY_set_public_key failed"); break; default: fatal("key_free: bad key type %d", k->type); break; } return (pk); } int key_is_cert(const Key *k) { if (k == NULL) return 0; switch (k->type) { case KEY_RSA_CERT_V00: case KEY_DSA_CERT_V00: case KEY_RSA_CERT: case KEY_DSA_CERT: case KEY_ECDSA_CERT: return 1; default: return 0; } } /* Return the cert-less equivalent to a certified key type */ int key_type_plain(int type) { switch (type) { case KEY_RSA_CERT_V00: case KEY_RSA_CERT: return KEY_RSA; case KEY_DSA_CERT_V00: case KEY_DSA_CERT: return KEY_DSA; case KEY_ECDSA_CERT: return KEY_ECDSA; default: return type; } } /* Convert a KEY_RSA or KEY_DSA to their _CERT equivalent */ int key_to_certified(Key *k, int legacy) { switch (k->type) { case KEY_RSA: k->cert = cert_new(); k->type = legacy ? KEY_RSA_CERT_V00 : KEY_RSA_CERT; return 0; case KEY_DSA: k->cert = cert_new(); k->type = legacy ? KEY_DSA_CERT_V00 : KEY_DSA_CERT; return 0; case KEY_ECDSA: if (legacy) fatal("%s: legacy ECDSA certificates are not supported", __func__); k->cert = cert_new(); k->type = KEY_ECDSA_CERT; return 0; default: error("%s: key has incorrect type %s", __func__, key_type(k)); return -1; } } /* Convert a KEY_RSA_CERT or KEY_DSA_CERT to their raw key equivalent */ int key_drop_cert(Key *k) { switch (k->type) { case KEY_RSA_CERT_V00: case KEY_RSA_CERT: cert_free(k->cert); k->type = KEY_RSA; return 0; case KEY_DSA_CERT_V00: case KEY_DSA_CERT: cert_free(k->cert); k->type = KEY_DSA; return 0; case KEY_ECDSA_CERT: cert_free(k->cert); k->type = KEY_ECDSA; return 0; default: error("%s: key has incorrect type %s", __func__, key_type(k)); return -1; } } /* * Sign a KEY_RSA_CERT, KEY_DSA_CERT or KEY_ECDSA_CERT, (re-)generating * the signed certblob */ int key_certify(Key *k, Key *ca) { Buffer principals; u_char *ca_blob, *sig_blob, nonce[32]; u_int i, ca_len, sig_len; if (k->cert == NULL) { error("%s: key lacks cert info", __func__); return -1; } if (!key_is_cert(k)) { error("%s: certificate has unknown type %d", __func__, k->cert->type); return -1; } if (ca->type != KEY_RSA && ca->type != KEY_DSA && ca->type != KEY_ECDSA) { error("%s: CA key has unsupported type %s", __func__, key_type(ca)); return -1; } key_to_blob(ca, &ca_blob, &ca_len); buffer_clear(&k->cert->certblob); buffer_put_cstring(&k->cert->certblob, key_ssh_name(k)); /* -v01 certs put nonce first */ arc4random_buf(&nonce, sizeof(nonce)); if (!key_cert_is_legacy(k)) buffer_put_string(&k->cert->certblob, nonce, sizeof(nonce)); switch (k->type) { case KEY_DSA_CERT_V00: case KEY_DSA_CERT: buffer_put_bignum2(&k->cert->certblob, k->dsa->p); buffer_put_bignum2(&k->cert->certblob, k->dsa->q); buffer_put_bignum2(&k->cert->certblob, k->dsa->g); buffer_put_bignum2(&k->cert->certblob, k->dsa->pub_key); break; case KEY_ECDSA_CERT: buffer_put_cstring(&k->cert->certblob, key_curve_nid_to_name(k->ecdsa_nid)); buffer_put_ecpoint(&k->cert->certblob, EC_KEY_get0_group(k->ecdsa), EC_KEY_get0_public_key(k->ecdsa)); break; case KEY_RSA_CERT_V00: case KEY_RSA_CERT: buffer_put_bignum2(&k->cert->certblob, k->rsa->e); buffer_put_bignum2(&k->cert->certblob, k->rsa->n); break; default: error("%s: key has incorrect type %s", __func__, key_type(k)); buffer_clear(&k->cert->certblob); xfree(ca_blob); return -1; } /* -v01 certs have a serial number next */ if (!key_cert_is_legacy(k)) buffer_put_int64(&k->cert->certblob, k->cert->serial); buffer_put_int(&k->cert->certblob, k->cert->type); buffer_put_cstring(&k->cert->certblob, k->cert->key_id); buffer_init(&principals); for (i = 0; i < k->cert->nprincipals; i++) buffer_put_cstring(&principals, k->cert->principals[i]); buffer_put_string(&k->cert->certblob, buffer_ptr(&principals), buffer_len(&principals)); buffer_free(&principals); buffer_put_int64(&k->cert->certblob, k->cert->valid_after); buffer_put_int64(&k->cert->certblob, k->cert->valid_before); buffer_put_string(&k->cert->certblob, buffer_ptr(&k->cert->critical), buffer_len(&k->cert->critical)); /* -v01 certs have non-critical options here */ if (!key_cert_is_legacy(k)) { buffer_put_string(&k->cert->certblob, buffer_ptr(&k->cert->extensions), buffer_len(&k->cert->extensions)); } /* -v00 certs put the nonce at the end */ if (key_cert_is_legacy(k)) buffer_put_string(&k->cert->certblob, nonce, sizeof(nonce)); buffer_put_string(&k->cert->certblob, NULL, 0); /* reserved */ buffer_put_string(&k->cert->certblob, ca_blob, ca_len); xfree(ca_blob); /* Sign the whole mess */ if (key_sign(ca, &sig_blob, &sig_len, buffer_ptr(&k->cert->certblob), buffer_len(&k->cert->certblob)) != 0) { error("%s: signature operation failed", __func__); buffer_clear(&k->cert->certblob); return -1; } /* Append signature and we are done */ buffer_put_string(&k->cert->certblob, sig_blob, sig_len); xfree(sig_blob); return 0; } int key_cert_check_authority(const Key *k, int want_host, int require_principal, const char *name, const char **reason) { u_int i, principal_matches; time_t now = time(NULL); if (want_host) { if (k->cert->type != SSH2_CERT_TYPE_HOST) { *reason = "Certificate invalid: not a host certificate"; return -1; } } else { if (k->cert->type != SSH2_CERT_TYPE_USER) { *reason = "Certificate invalid: not a user certificate"; return -1; } } if (now < 0) { error("%s: system clock lies before epoch", __func__); *reason = "Certificate invalid: not yet valid"; return -1; } if ((u_int64_t)now < k->cert->valid_after) { *reason = "Certificate invalid: not yet valid"; return -1; } if ((u_int64_t)now >= k->cert->valid_before) { *reason = "Certificate invalid: expired"; return -1; } if (k->cert->nprincipals == 0) { if (require_principal) { *reason = "Certificate lacks principal list"; return -1; } } else if (name != NULL) { principal_matches = 0; for (i = 0; i < k->cert->nprincipals; i++) { if (strcmp(name, k->cert->principals[i]) == 0) { principal_matches = 1; break; } } if (!principal_matches) { *reason = "Certificate invalid: name is not a listed " "principal"; return -1; } } return 0; } int key_cert_is_legacy(Key *k) { switch (k->type) { case KEY_DSA_CERT_V00: case KEY_RSA_CERT_V00: return 1; default: return 0; } } /* XXX: these are really begging for a table-driven approach */ int key_curve_name_to_nid(const char *name) { if (strcmp(name, "nistp256") == 0) return NID_X9_62_prime256v1; else if (strcmp(name, "nistp384") == 0) return NID_secp384r1; else if (strcmp(name, "nistp521") == 0) return NID_secp521r1; debug("%s: unsupported EC curve name \"%.100s\"", __func__, name); return -1; } u_int key_curve_nid_to_bits(int nid) { switch (nid) { case NID_X9_62_prime256v1: return 256; case NID_secp384r1: return 384; case NID_secp521r1: return 521; default: error("%s: unsupported EC curve nid %d", __func__, nid); return 0; } } const char * key_curve_nid_to_name(int nid) { if (nid == NID_X9_62_prime256v1) return "nistp256"; else if (nid == NID_secp384r1) return "nistp384"; else if (nid == NID_secp521r1) return "nistp521"; error("%s: unsupported EC curve nid %d", __func__, nid); return NULL; } const EVP_MD * key_ec_nid_to_evpmd(int nid) { int kbits = key_curve_nid_to_bits(nid); if (kbits == 0) fatal("%s: invalid nid %d", __func__, nid); /* RFC5656 section 6.2.1 */ if (kbits <= 256) return EVP_sha256(); else if (kbits <= 384) return EVP_sha384(); else return EVP_sha512(); } int key_ec_validate_public(const EC_GROUP *group, const EC_POINT *public) { BN_CTX *bnctx; EC_POINT *nq = NULL; BIGNUM *order, *x, *y, *tmp; int ret = -1; if ((bnctx = BN_CTX_new()) == NULL) fatal("%s: BN_CTX_new failed", __func__); BN_CTX_start(bnctx); /* * We shouldn't ever hit this case because bignum_get_ecpoint() * refuses to load GF2m points. */ if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) != NID_X9_62_prime_field) { error("%s: group is not a prime field", __func__); goto out; } /* Q != infinity */ if (EC_POINT_is_at_infinity(group, public)) { error("%s: received degenerate public key (infinity)", __func__); goto out; } if ((x = BN_CTX_get(bnctx)) == NULL || (y = BN_CTX_get(bnctx)) == NULL || (order = BN_CTX_get(bnctx)) == NULL || (tmp = BN_CTX_get(bnctx)) == NULL) fatal("%s: BN_CTX_get failed", __func__); /* log2(x) > log2(order)/2, log2(y) > log2(order)/2 */ if (EC_GROUP_get_order(group, order, bnctx) != 1) fatal("%s: EC_GROUP_get_order failed", __func__); if (EC_POINT_get_affine_coordinates_GFp(group, public, x, y, bnctx) != 1) fatal("%s: EC_POINT_get_affine_coordinates_GFp", __func__); if (BN_num_bits(x) <= BN_num_bits(order) / 2) { error("%s: public key x coordinate too small: " "bits(x) = %d, bits(order)/2 = %d", __func__, BN_num_bits(x), BN_num_bits(order) / 2); goto out; } if (BN_num_bits(y) <= BN_num_bits(order) / 2) { error("%s: public key y coordinate too small: " "bits(y) = %d, bits(order)/2 = %d", __func__, BN_num_bits(x), BN_num_bits(order) / 2); goto out; } /* nQ == infinity (n == order of subgroup) */ if ((nq = EC_POINT_new(group)) == NULL) fatal("%s: BN_CTX_tmp failed", __func__); if (EC_POINT_mul(group, nq, NULL, public, order, bnctx) != 1) fatal("%s: EC_GROUP_mul failed", __func__); if (EC_POINT_is_at_infinity(group, nq) != 1) { error("%s: received degenerate public key (nQ != infinity)", __func__); goto out; } /* x < order - 1, y < order - 1 */ if (!BN_sub(tmp, order, BN_value_one())) fatal("%s: BN_sub failed", __func__); if (BN_cmp(x, tmp) >= 0) { error("%s: public key x coordinate >= group order - 1", __func__); goto out; } if (BN_cmp(y, tmp) >= 0) { error("%s: public key y coordinate >= group order - 1", __func__); goto out; } ret = 0; out: BN_CTX_free(bnctx); EC_POINT_free(nq); return ret; } int key_ec_validate_private(const EC_KEY *key) { BN_CTX *bnctx; BIGNUM *order, *tmp; int ret = -1; if ((bnctx = BN_CTX_new()) == NULL) fatal("%s: BN_CTX_new failed", __func__); BN_CTX_start(bnctx); if ((order = BN_CTX_get(bnctx)) == NULL || (tmp = BN_CTX_get(bnctx)) == NULL) fatal("%s: BN_CTX_get failed", __func__); /* log2(private) > log2(order)/2 */ if (EC_GROUP_get_order(EC_KEY_get0_group(key), order, bnctx) != 1) fatal("%s: EC_GROUP_get_order failed", __func__); if (BN_num_bits(EC_KEY_get0_private_key(key)) <= BN_num_bits(order) / 2) { error("%s: private key too small: " "bits(y) = %d, bits(order)/2 = %d", __func__, BN_num_bits(EC_KEY_get0_private_key(key)), BN_num_bits(order) / 2); goto out; } /* private < order - 1 */ if (!BN_sub(tmp, order, BN_value_one())) fatal("%s: BN_sub failed", __func__); if (BN_cmp(EC_KEY_get0_private_key(key), tmp) >= 0) { error("%s: private key >= group order - 1", __func__); goto out; } ret = 0; out: BN_CTX_free(bnctx); return ret; } #if defined(DEBUG_KEXECDH) || defined(DEBUG_PK) void key_dump_ec_point(const EC_GROUP *group, const EC_POINT *point) { BIGNUM *x, *y; BN_CTX *bnctx; if (point == NULL) { fputs("point=(NULL)\n", stderr); return; } if ((bnctx = BN_CTX_new()) == NULL) fatal("%s: BN_CTX_new failed", __func__); BN_CTX_start(bnctx); if ((x = BN_CTX_get(bnctx)) == NULL || (y = BN_CTX_get(bnctx)) == NULL) fatal("%s: BN_CTX_get failed", __func__); if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) != NID_X9_62_prime_field) fatal("%s: group is not a prime field", __func__); if (EC_POINT_get_affine_coordinates_GFp(group, point, x, y, bnctx) != 1) fatal("%s: EC_POINT_get_affine_coordinates_GFp", __func__); fputs("x=", stderr); BN_print_fp(stderr, x); fputs("\ny=", stderr); BN_print_fp(stderr, y); fputs("\n", stderr); BN_CTX_free(bnctx); } void key_dump_ec_key(const EC_KEY *key) { const BIGNUM *exponent; key_dump_ec_point(EC_KEY_get0_group(key), EC_KEY_get0_public_key(key)); fputs("exponent=", stderr); if ((exponent = EC_KEY_get0_private_key(key)) == NULL) fputs("(NULL)", stderr); else BN_print_fp(stderr, EC_KEY_get0_private_key(key)); fputs("\n", stderr); } #endif /* defined(DEBUG_KEXECDH) || defined(DEBUG_PK) */