# HG changeset patch # User Matt Johnston # Date 1648606215 -28800 # Node ID f978a15194baa326fe672a8a42c427f587c31573 # Parent 38c6fd7d7a82cde56d326d5afdbcd988a99c3c0a Remove commented ssh.com code from keyimport diff -r 38c6fd7d7a82 -r f978a15194ba keyimport.c --- a/keyimport.c Tue Mar 29 23:55:35 2022 +0800 +++ b/keyimport.c Wed Mar 30 10:10:15 2022 +0800 @@ -2,7 +2,7 @@ * Based on PuTTY's import.c for importing/exporting OpenSSH and SSH.com * keyfiles. * - * Modifications copyright 2003 Matt Johnston + * Modifications copyright 2003-2022 Matt Johnston * * PuTTY is copyright 1997-2003 Simon Tatham. * @@ -1121,733 +1121,6 @@ return ret; } -#if 0 -/* XXX TODO ssh.com stuff isn't going yet */ - -/* ---------------------------------------------------------------------- - * Code to read ssh.com private keys. - */ - -/* - * The format of the base64 blob is largely ssh2-packet-formatted, - * except that mpints are a bit different: they're more like the - * old ssh1 mpint. You have a 32-bit bit count N, followed by - * (N+7)/8 bytes of data. - * - * So. The blob contains: - * - * - uint32 0x3f6ff9eb (magic number) - * - uint32 size (total blob size) - * - string key-type (see below) - * - string cipher-type (tells you if key is encrypted) - * - string encrypted-blob - * - * (The first size field includes the size field itself and the - * magic number before it. All other size fields are ordinary ssh2 - * strings, so the size field indicates how much data is to - * _follow_.) - * - * The encrypted blob, once decrypted, contains a single string - * which in turn contains the payload. (This allows padding to be - * added after that string while still making it clear where the - * real payload ends. Also it probably makes for a reasonable - * decryption check.) - * - * The payload blob, for an RSA key, contains: - * - mpint e - * - mpint d - * - mpint n (yes, the public and private stuff is intermixed) - * - mpint u (presumably inverse of p mod q) - * - mpint p (p is the smaller prime) - * - mpint q (q is the larger) - * - * For a DSA key, the payload blob contains: - * - uint32 0 - * - mpint p - * - mpint g - * - mpint q - * - mpint y - * - mpint x - * - * Alternatively, if the parameters are `predefined', that - * (0,p,g,q) sequence can be replaced by a uint32 1 and a string - * containing some predefined parameter specification. *shudder*, - * but I doubt we'll encounter this in real life. - * - * The key type strings are ghastly. The RSA key I looked at had a - * type string of - * - * `if-modn{sign{rsa-pkcs1-sha1},encrypt{rsa-pkcs1v2-oaep}}' - * - * and the DSA key wasn't much better: - * - * `dl-modp{sign{dsa-nist-sha1},dh{plain}}' - * - * It isn't clear that these will always be the same. I think it - * might be wise just to look at the `if-modn{sign{rsa' and - * `dl-modp{sign{dsa' prefixes. - * - * Finally, the encryption. The cipher-type string appears to be - * either `none' or `3des-cbc'. Looks as if this is SSH2-style - * 3des-cbc (i.e. outer cbc rather than inner). The key is created - * from the passphrase by means of yet another hashing faff: - * - * - first 16 bytes are MD5(passphrase) - * - next 16 bytes are MD5(passphrase || first 16 bytes) - * - if there were more, they'd be MD5(passphrase || first 32), - * and so on. - */ - -#define SSHCOM_MAGIC_NUMBER 0x3f6ff9eb - -struct sshcom_key { - char comment[256]; /* allowing any length is overkill */ - unsigned char *keyblob; - int keyblob_len, keyblob_size; -}; - -static struct sshcom_key *load_sshcom_key(const char *filename) -{ - struct sshcom_key *ret; - FILE *fp; - char buffer[256]; - int len; - char *errmsg, *p; - int headers_done; - char base64_bit[4]; - int base64_chars = 0; - - ret = snew(struct sshcom_key); - ret->comment[0] = '\0'; - ret->keyblob = NULL; - ret->keyblob_len = ret->keyblob_size = 0; - - fp = fopen(filename, "r"); - if (!fp) { - errmsg = "Unable to open key file"; - goto error; - } - if (!fgets(buffer, sizeof(buffer), fp) || - 0 != strcmp(buffer, "---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----\n")) { - errmsg = "File does not begin with ssh.com key header"; - goto error; - } - - headers_done = 0; - while (1) { - if (!fgets(buffer, sizeof(buffer), fp)) { - errmsg = "Unexpected end of file"; - goto error; - } - if (!strcmp(buffer, "---- END SSH2 ENCRYPTED PRIVATE KEY ----\n")) - break; /* done */ - if ((p = strchr(buffer, ':')) != NULL) { - if (headers_done) { - errmsg = "Header found in body of key data"; - goto error; - } - *p++ = '\0'; - while (*p && isspace((unsigned char)*p)) p++; - /* - * Header lines can end in a trailing backslash for - * continuation. - */ - while ((len = strlen(p)) > (int)(sizeof(buffer) - (p-buffer) -1) || - p[len-1] != '\n' || p[len-2] == '\\') { - if (len > (int)((p-buffer) + sizeof(buffer)-2)) { - errmsg = "Header line too long to deal with"; - goto error; - } - if (!fgets(p+len-2, sizeof(buffer)-(p-buffer)-(len-2), fp)) { - errmsg = "Unexpected end of file"; - goto error; - } - } - p[strcspn(p, "\n")] = '\0'; - if (!strcmp(buffer, "Comment")) { - /* Strip quotes in comment if present. */ - if (p[0] == '"' && p[strlen(p)-1] == '"') { - p++; - p[strlen(p)-1] = '\0'; - } - strncpy(ret->comment, p, sizeof(ret->comment)); - ret->comment[sizeof(ret->comment)-1] = '\0'; - } - } else { - headers_done = 1; - - p = buffer; - while (isbase64(*p)) { - base64_bit[base64_chars++] = *p; - if (base64_chars == 4) { - unsigned char out[3]; - - base64_chars = 0; - - len = base64_decode_atom(base64_bit, out); - - if (len <= 0) { - errmsg = "Invalid base64 encoding"; - goto error; - } - - if (ret->keyblob_len + len > ret->keyblob_size) { - ret->keyblob_size = ret->keyblob_len + len + 256; - ret->keyblob = sresize(ret->keyblob, ret->keyblob_size, - unsigned char); - } - - memcpy(ret->keyblob + ret->keyblob_len, out, len); - ret->keyblob_len += len; - } - - p++; - } - } - } - - if (ret->keyblob_len == 0 || !ret->keyblob) { - errmsg = "Key body not present"; - goto error; - } - - return ret; - - error: - if (ret) { - if (ret->keyblob) { - memset(ret->keyblob, 0, ret->keyblob_size); - m_free(ret->keyblob); - } - memset(ret, 0, sizeof(*ret)); - m_free(ret); - } - return NULL; -} - -int sshcom_encrypted(const char *filename, char **comment) -{ - struct sshcom_key *key = load_sshcom_key(filename); - int pos, len, answer; - - *comment = NULL; - if (!key) - return 0; - - /* - * Check magic number. - */ - if (GET_32BIT(key->keyblob) != 0x3f6ff9eb) - return 0; /* key is invalid */ - - /* - * Find the cipher-type string. - */ - answer = 0; - pos = 8; - if (key->keyblob_len < pos+4) - goto done; /* key is far too short */ - len = toint(GET_32BIT(key->keyblob + pos)); - if (len < 0 || len > key->keyblob_len - pos - 4) - goto done; /* key is far too short */ - pos += 4 + len; /* skip key type */ - len = toint(GET_32BIT(key->keyblob + pos)); /* find cipher-type length */ - if (len < 0 || len > key->keyblob_len - pos - 4) - goto done; /* cipher type string is incomplete */ - if (len != 4 || 0 != memcmp(key->keyblob + pos + 4, "none", 4)) - answer = 1; - - done: - *comment = dupstr(key->comment); - memset(key->keyblob, 0, key->keyblob_size); - m_free(key->keyblob); - memset(key, 0, sizeof(*key)); - m_free(key); - return answer; -} - -static int sshcom_read_mpint(void *data, int len, struct mpint_pos *ret) -{ - unsigned bits, bytes; - unsigned char *d = (unsigned char *) data; - - if (len < 4) - goto error; - bits = GET_32BIT(d); - - bytes = (bits + 7) / 8; - if (len < 4+bytes) - goto error; - - ret->start = d + 4; - ret->bytes = bytes; - return bytes+4; - - error: - ret->start = NULL; - ret->bytes = -1; - return len; /* ensure further calls fail as well */ -} - -static int sshcom_put_mpint(void *target, void *data, int len) -{ - unsigned char *d = (unsigned char *)target; - unsigned char *i = (unsigned char *)data; - int bits = len * 8 - 1; - - while (bits > 0) { - if (*i & (1 << (bits & 7))) - break; - if (!(bits-- & 7)) - i++, len--; - } - - PUT_32BIT(d, bits+1); - memcpy(d+4, i, len); - return len+4; -} - -sign_key *sshcom_read(const char *filename, char *passphrase) -{ - struct sshcom_key *key = load_sshcom_key(filename); - char *errmsg; - int pos, len; - const char prefix_rsa[] = "if-modn{sign{rsa"; - const char prefix_dsa[] = "dl-modp{sign{dsa"; - enum { RSA, DSA } type; - int encrypted; - char *ciphertext; - int cipherlen; - struct ssh2_userkey *ret = NULL, *retkey; - const struct ssh_signkey *alg; - unsigned char *blob = NULL; - int blobsize = 0, publen, privlen; - - if (!key) - return NULL; - - /* - * Check magic number. - */ - if (GET_32BIT(key->keyblob) != SSHCOM_MAGIC_NUMBER) { - errmsg = "Key does not begin with magic number"; - goto error; - } - - /* - * Determine the key type. - */ - pos = 8; - if (key->keyblob_len < pos+4 || - (len = GET_32BIT(key->keyblob + pos)) > key->keyblob_len - pos - 4) { - errmsg = "Key blob does not contain a key type string"; - goto error; - } - if (len > sizeof(prefix_rsa) - 1 && - !memcmp(key->keyblob+pos+4, prefix_rsa, sizeof(prefix_rsa) - 1)) { - type = RSA; - } else if (len > sizeof(prefix_dsa) - 1 && - !memcmp(key->keyblob+pos+4, prefix_dsa, sizeof(prefix_dsa) - 1)) { - type = DSA; - } else { - errmsg = "Key is of unknown type"; - goto error; - } - pos += 4+len; - - /* - * Determine the cipher type. - */ - if (key->keyblob_len < pos+4 || - (len = GET_32BIT(key->keyblob + pos)) > key->keyblob_len - pos - 4) { - errmsg = "Key blob does not contain a cipher type string"; - goto error; - } - if (len == 4 && !memcmp(key->keyblob+pos+4, "none", 4)) - encrypted = 0; - else if (len == 8 && !memcmp(key->keyblob+pos+4, "3des-cbc", 8)) - encrypted = 1; - else { - errmsg = "Key encryption is of unknown type"; - goto error; - } - pos += 4+len; - - /* - * Get hold of the encrypted part of the key. - */ - if (key->keyblob_len < pos+4 || - (len = GET_32BIT(key->keyblob + pos)) > key->keyblob_len - pos - 4) { - errmsg = "Key blob does not contain actual key data"; - goto error; - } - ciphertext = (char *)key->keyblob + pos + 4; - cipherlen = len; - if (cipherlen == 0) { - errmsg = "Length of key data is zero"; - goto error; - } - - /* - * Decrypt it if necessary. - */ - if (encrypted) { - /* - * Derive encryption key from passphrase and iv/salt: - * - * - let block A equal MD5(passphrase) - * - let block B equal MD5(passphrase || A) - * - block C would be MD5(passphrase || A || B) and so on - * - encryption key is the first N bytes of A || B - */ - struct MD5Context md5c; - unsigned char keybuf[32], iv[8]; - - if (cipherlen % 8 != 0) { - errmsg = "Encrypted part of key is not a multiple of cipher block" - " size"; - goto error; - } - - MD5Init(&md5c); - MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); - MD5Final(keybuf, &md5c); - - MD5Init(&md5c); - MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); - MD5Update(&md5c, keybuf, 16); - MD5Final(keybuf+16, &md5c); - - /* - * Now decrypt the key blob. - */ - memset(iv, 0, sizeof(iv)); - des3_decrypt_pubkey_ossh(keybuf, iv, (unsigned char *)ciphertext, - cipherlen); - - memset(&md5c, 0, sizeof(md5c)); - memset(keybuf, 0, sizeof(keybuf)); - - /* - * Hereafter we return WRONG_PASSPHRASE for any parsing - * error. (But only if we've just tried to decrypt it! - * Returning WRONG_PASSPHRASE for an unencrypted key is - * automatic doom.) - */ - if (encrypted) - ret = SSH2_WRONG_PASSPHRASE; - } - - /* - * Strip away the containing string to get to the real meat. - */ - len = toint(GET_32BIT(ciphertext)); - if (len < 0 || len > cipherlen-4) { - errmsg = "containing string was ill-formed"; - goto error; - } - ciphertext += 4; - cipherlen = len; - - /* - * Now we break down into RSA versus DSA. In either case we'll - * construct public and private blobs in our own format, and - * end up feeding them to alg->createkey(). - */ - blobsize = cipherlen + 256; - blob = snewn(blobsize, unsigned char); - privlen = 0; - if (type == RSA) { - struct mpint_pos n, e, d, u, p, q; - int pos = 0; - pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &e); - pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &d); - pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &n); - pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &u); - pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &p); - pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &q); - if (!q.start) { - errmsg = "key data did not contain six integers"; - goto error; - } - - alg = &ssh_rsa; - pos = 0; - pos += put_string(blob+pos, "ssh-rsa", 7); - pos += put_mp(blob+pos, e.start, e.bytes); - pos += put_mp(blob+pos, n.start, n.bytes); - publen = pos; - pos += put_string(blob+pos, d.start, d.bytes); - pos += put_mp(blob+pos, q.start, q.bytes); - pos += put_mp(blob+pos, p.start, p.bytes); - pos += put_mp(blob+pos, u.start, u.bytes); - privlen = pos - publen; - } else if (type == DSA) { - struct mpint_pos p, q, g, x, y; - int pos = 4; - if (GET_32BIT(ciphertext) != 0) { - errmsg = "predefined DSA parameters not supported"; - goto error; - } - pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &p); - pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &g); - pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &q); - pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &y); - pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &x); - if (!x.start) { - errmsg = "key data did not contain five integers"; - goto error; - } - - alg = &ssh_dss; - pos = 0; - pos += put_string(blob+pos, "ssh-dss", 7); - pos += put_mp(blob+pos, p.start, p.bytes); - pos += put_mp(blob+pos, q.start, q.bytes); - pos += put_mp(blob+pos, g.start, g.bytes); - pos += put_mp(blob+pos, y.start, y.bytes); - publen = pos; - pos += put_mp(blob+pos, x.start, x.bytes); - privlen = pos - publen; - } else - return NULL; - - dropbear_assert(privlen > 0); /* should have bombed by now if not */ - - retkey = snew(struct ssh2_userkey); - retkey->alg = alg; - retkey->data = alg->createkey(blob, publen, blob+publen, privlen); - if (!retkey->data) { - m_free(retkey); - errmsg = "unable to create key data structure"; - goto error; - } - retkey->comment = dupstr(key->comment); - - errmsg = NULL; /* no error */ - ret = retkey; - - error: - if (blob) { - memset(blob, 0, blobsize); - m_free(blob); - } - memset(key->keyblob, 0, key->keyblob_size); - m_free(key->keyblob); - memset(key, 0, sizeof(*key)); - m_free(key); - return ret; -} - -int sshcom_write(const char *filename, sign_key *key, - char *passphrase) -{ - unsigned char *pubblob, *privblob; - int publen, privlen; - unsigned char *outblob; - int outlen; - struct mpint_pos numbers[6]; - int nnumbers, initial_zero, pos, lenpos, i; - char *type; - char *ciphertext; - int cipherlen; - int ret = 0; - FILE *fp; - - /* - * Fetch the key blobs. - */ - pubblob = key->alg->public_blob(key->data, &publen); - privblob = key->alg->private_blob(key->data, &privlen); - outblob = NULL; - - /* - * Find the sequence of integers to be encoded into the OpenSSH - * key blob, and also decide on the header line. - */ - if (key->alg == &ssh_rsa) { - int pos; - struct mpint_pos n, e, d, p, q, iqmp; - - pos = 4 + GET_32BIT(pubblob); - pos += ssh2_read_mpint(pubblob+pos, publen-pos, &e); - pos += ssh2_read_mpint(pubblob+pos, publen-pos, &n); - pos = 0; - pos += ssh2_read_mpint(privblob+pos, privlen-pos, &d); - pos += ssh2_read_mpint(privblob+pos, privlen-pos, &p); - pos += ssh2_read_mpint(privblob+pos, privlen-pos, &q); - pos += ssh2_read_mpint(privblob+pos, privlen-pos, &iqmp); - - dropbear_assert(e.start && iqmp.start); /* can't go wrong */ - - numbers[0] = e; - numbers[1] = d; - numbers[2] = n; - numbers[3] = iqmp; - numbers[4] = q; - numbers[5] = p; - - nnumbers = 6; - initial_zero = 0; - type = "if-modn{sign{rsa-pkcs1-sha1},encrypt{rsa-pkcs1v2-oaep}}"; - } else if (key->alg == &ssh_dss) { - int pos; - struct mpint_pos p, q, g, y, x; - - pos = 4 + GET_32BIT(pubblob); - pos += ssh2_read_mpint(pubblob+pos, publen-pos, &p); - pos += ssh2_read_mpint(pubblob+pos, publen-pos, &q); - pos += ssh2_read_mpint(pubblob+pos, publen-pos, &g); - pos += ssh2_read_mpint(pubblob+pos, publen-pos, &y); - pos = 0; - pos += ssh2_read_mpint(privblob+pos, privlen-pos, &x); - - dropbear_assert(y.start && x.start); /* can't go wrong */ - - numbers[0] = p; - numbers[1] = g; - numbers[2] = q; - numbers[3] = y; - numbers[4] = x; - - nnumbers = 5; - initial_zero = 1; - type = "dl-modp{sign{dsa-nist-sha1},dh{plain}}"; - } else { - dropbear_assert(0); /* zoinks! */ - } - - /* - * Total size of key blob will be somewhere under 512 plus - * combined length of integers. We'll calculate the more - * precise size as we construct the blob. - */ - outlen = 512; - for (i = 0; i < nnumbers; i++) - outlen += 4 + numbers[i].bytes; - outblob = snewn(outlen, unsigned char); - - /* - * Create the unencrypted key blob. - */ - pos = 0; - PUT_32BIT(outblob+pos, SSHCOM_MAGIC_NUMBER); pos += 4; - pos += 4; /* length field, fill in later */ - pos += put_string(outblob+pos, type, strlen(type)); - { - char *ciphertype = passphrase ? "3des-cbc" : "none"; - pos += put_string(outblob+pos, ciphertype, strlen(ciphertype)); - } - lenpos = pos; /* remember this position */ - pos += 4; /* encrypted-blob size */ - pos += 4; /* encrypted-payload size */ - if (initial_zero) { - PUT_32BIT(outblob+pos, 0); - pos += 4; - } - for (i = 0; i < nnumbers; i++) - pos += sshcom_put_mpint(outblob+pos, - numbers[i].start, numbers[i].bytes); - /* Now wrap up the encrypted payload. */ - PUT_32BIT(outblob+lenpos+4, pos - (lenpos+8)); - /* Pad encrypted blob to a multiple of cipher block size. */ - if (passphrase) { - int padding = -(pos - (lenpos+4)) & 7; - while (padding--) - outblob[pos++] = random_byte(); - } - ciphertext = (char *)outblob+lenpos+4; - cipherlen = pos - (lenpos+4); - dropbear_assert(!passphrase || cipherlen % 8 == 0); - /* Wrap up the encrypted blob string. */ - PUT_32BIT(outblob+lenpos, cipherlen); - /* And finally fill in the total length field. */ - PUT_32BIT(outblob+4, pos); - - dropbear_assert(pos < outlen); - - /* - * Encrypt the key. - */ - if (passphrase) { - /* - * Derive encryption key from passphrase and iv/salt: - * - * - let block A equal MD5(passphrase) - * - let block B equal MD5(passphrase || A) - * - block C would be MD5(passphrase || A || B) and so on - * - encryption key is the first N bytes of A || B - */ - struct MD5Context md5c; - unsigned char keybuf[32], iv[8]; - - MD5Init(&md5c); - MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); - MD5Final(keybuf, &md5c); - - MD5Init(&md5c); - MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); - MD5Update(&md5c, keybuf, 16); - MD5Final(keybuf+16, &md5c); - - /* - * Now decrypt the key blob. - */ - memset(iv, 0, sizeof(iv)); - des3_encrypt_pubkey_ossh(keybuf, iv, (unsigned char *)ciphertext, - cipherlen); - - memset(&md5c, 0, sizeof(md5c)); - memset(keybuf, 0, sizeof(keybuf)); - } - - /* - * And save it. We'll use Unix line endings just in case it's - * subsequently transferred in binary mode. - */ - fp = fopen(filename, "wb"); /* ensure Unix line endings */ - if (!fp) - goto error; - fputs("---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----\n", fp); - fprintf(fp, "Comment: \""); - /* - * Comment header is broken with backslash-newline if it goes - * over 70 chars. Although it's surrounded by quotes, it - * _doesn't_ escape backslashes or quotes within the string. - * Don't ask me, I didn't design it. - */ - { - int slen = 60; /* starts at 60 due to "Comment: " */ - char *c = key->comment; - while ((int)strlen(c) > slen) { - fprintf(fp, "%.*s\\\n", slen, c); - c += slen; - slen = 70; /* allow 70 chars on subsequent lines */ - } - fprintf(fp, "%s\"\n", c); - } - base64_encode_fp(fp, outblob, pos, 70); - fputs("---- END SSH2 ENCRYPTED PRIVATE KEY ----\n", fp); - fclose(fp); - ret = 1; - - error: - if (outblob) { - memset(outblob, 0, outlen); - m_free(outblob); - } - if (privblob) { - memset(privblob, 0, privlen); - m_free(privblob); - } - if (pubblob) { - memset(pubblob, 0, publen); - m_free(pubblob); - } - return ret; -} -#endif /* ssh.com stuff disabled */ - /* From PuTTY misc.c */ static int toint(unsigned u) {