2 * Code for PuTTY to import and export private key files in other
3 * SSH clients' formats.
15 int openssh_pem_encrypted(const Filename *filename);
16 int openssh_new_encrypted(const Filename *filename);
17 struct ssh2_userkey *openssh_pem_read(const Filename *filename,
19 const char **errmsg_p);
20 struct ssh2_userkey *openssh_new_read(const Filename *filename,
22 const char **errmsg_p);
23 int openssh_auto_write(const Filename *filename, struct ssh2_userkey *key,
25 int openssh_pem_write(const Filename *filename, struct ssh2_userkey *key,
27 int openssh_new_write(const Filename *filename, struct ssh2_userkey *key,
30 int sshcom_encrypted(const Filename *filename, char **comment);
31 struct ssh2_userkey *sshcom_read(const Filename *filename, char *passphrase,
32 const char **errmsg_p);
33 int sshcom_write(const Filename *filename, struct ssh2_userkey *key,
37 * Given a key type, determine whether we know how to import it.
39 int import_possible(int type)
41 if (type == SSH_KEYTYPE_OPENSSH_PEM)
43 if (type == SSH_KEYTYPE_OPENSSH_NEW)
45 if (type == SSH_KEYTYPE_SSHCOM)
51 * Given a key type, determine what native key type
52 * (SSH_KEYTYPE_SSH1 or SSH_KEYTYPE_SSH2) it will come out as once
55 int import_target_type(int type)
58 * There are no known foreign SSH-1 key formats.
60 return SSH_KEYTYPE_SSH2;
64 * Determine whether a foreign key is encrypted.
66 int import_encrypted(const Filename *filename, int type, char **comment)
68 if (type == SSH_KEYTYPE_OPENSSH_PEM) {
69 /* OpenSSH PEM format doesn't contain a key comment at all */
70 *comment = dupstr(filename_to_str(filename));
71 return openssh_pem_encrypted(filename);
72 } else if (type == SSH_KEYTYPE_OPENSSH_NEW) {
73 /* OpenSSH new format does, but it's inside the encrypted
74 * section for some reason */
75 *comment = dupstr(filename_to_str(filename));
76 return openssh_new_encrypted(filename);
77 } else if (type == SSH_KEYTYPE_SSHCOM) {
78 return sshcom_encrypted(filename, comment);
84 * Import an SSH-1 key.
86 int import_ssh1(const Filename *filename, int type,
87 struct RSAKey *key, char *passphrase, const char **errmsg_p)
93 * Import an SSH-2 key.
95 struct ssh2_userkey *import_ssh2(const Filename *filename, int type,
96 char *passphrase, const char **errmsg_p)
98 if (type == SSH_KEYTYPE_OPENSSH_PEM)
99 return openssh_pem_read(filename, passphrase, errmsg_p);
100 else if (type == SSH_KEYTYPE_OPENSSH_NEW)
101 return openssh_new_read(filename, passphrase, errmsg_p);
102 if (type == SSH_KEYTYPE_SSHCOM)
103 return sshcom_read(filename, passphrase, errmsg_p);
108 * Export an SSH-1 key.
110 int export_ssh1(const Filename *filename, int type, struct RSAKey *key,
117 * Export an SSH-2 key.
119 int export_ssh2(const Filename *filename, int type,
120 struct ssh2_userkey *key, char *passphrase)
122 if (type == SSH_KEYTYPE_OPENSSH_AUTO)
123 return openssh_auto_write(filename, key, passphrase);
124 if (type == SSH_KEYTYPE_OPENSSH_NEW)
125 return openssh_new_write(filename, key, passphrase);
126 if (type == SSH_KEYTYPE_SSHCOM)
127 return sshcom_write(filename, key, passphrase);
132 * Strip trailing CRs and LFs at the end of a line of text.
134 void strip_crlf(char *str)
136 char *p = str + strlen(str);
138 while (p > str && (p[-1] == '\r' || p[-1] == '\n'))
142 /* ----------------------------------------------------------------------
143 * Helper routines. (The base64 ones are defined in sshpubk.c.)
146 #define isbase64(c) ( ((c) >= 'A' && (c) <= 'Z') || \
147 ((c) >= 'a' && (c) <= 'z') || \
148 ((c) >= '0' && (c) <= '9') || \
149 (c) == '+' || (c) == '/' || (c) == '=' \
153 * Read an ASN.1/BER identifier and length pair.
155 * Flags are a combination of the #defines listed below.
157 * Returns -1 if unsuccessful; otherwise returns the number of
158 * bytes used out of the source data.
161 /* ASN.1 tag classes. */
162 #define ASN1_CLASS_UNIVERSAL (0 << 6)
163 #define ASN1_CLASS_APPLICATION (1 << 6)
164 #define ASN1_CLASS_CONTEXT_SPECIFIC (2 << 6)
165 #define ASN1_CLASS_PRIVATE (3 << 6)
166 #define ASN1_CLASS_MASK (3 << 6)
168 /* Primitive versus constructed bit. */
169 #define ASN1_CONSTRUCTED (1 << 5)
171 static int ber_read_id_len(void *source, int sourcelen,
172 int *id, int *length, int *flags)
174 unsigned char *p = (unsigned char *) source;
179 *flags = (*p & 0xE0);
180 if ((*p & 0x1F) == 0x1F) {
186 *id = (*id << 7) | (*p & 0x7F);
204 *length = (*length << 8) | (*p++);
211 return p - (unsigned char *) source;
215 * Write an ASN.1/BER identifier and length pair. Returns the
216 * number of bytes consumed. Assumes dest contains enough space.
217 * Will avoid writing anything if dest is NULL, but still return
218 * amount of space required.
220 static int ber_write_id_len(void *dest, int id, int length, int flags)
222 unsigned char *d = (unsigned char *)dest;
227 * Identifier is one byte.
230 if (d) *d++ = id | flags;
234 * Identifier is multiple bytes: the first byte is 11111
235 * plus the flags, and subsequent bytes encode the value of
236 * the identifier, 7 bits at a time, with the top bit of
237 * each byte 1 except the last one which is 0.
240 if (d) *d++ = 0x1F | flags;
241 for (n = 1; (id >> (7*n)) > 0; n++)
242 continue; /* count the bytes */
245 if (d) *d++ = (n ? 0x80 : 0) | ((id >> (7*n)) & 0x7F);
251 * Length is one byte.
254 if (d) *d++ = length;
258 * Length is multiple bytes. The first is 0x80 plus the
259 * number of subsequent bytes, and the subsequent bytes
260 * encode the actual length.
262 for (n = 1; (length >> (8*n)) > 0; n++)
263 continue; /* count the bytes */
265 if (d) *d++ = 0x80 | n;
268 if (d) *d++ = (length >> (8*n)) & 0xFF;
275 static int put_uint32(void *target, unsigned val)
277 unsigned char *d = (unsigned char *)target;
283 static int put_string(void *target, const void *data, int len)
285 unsigned char *d = (unsigned char *)target;
288 memcpy(d+4, data, len);
292 static int put_string_z(void *target, const char *string)
294 return put_string(target, string, strlen(string));
297 static int put_mp(void *target, void *data, int len)
299 unsigned char *d = (unsigned char *)target;
300 unsigned char *i = (unsigned char *)data;
305 memcpy(d+5, data, len);
309 memcpy(d+4, data, len);
314 /* Simple structure to point to an mp-int within a blob. */
315 struct mpint_pos { void *start; int bytes; };
317 static int ssh2_read_mpint(void *data, int len, struct mpint_pos *ret)
320 unsigned char *d = (unsigned char *) data;
324 bytes = toint(GET_32BIT(d));
325 if (bytes < 0 || len-4 < bytes)
335 return len; /* ensure further calls fail as well */
338 /* ----------------------------------------------------------------------
339 * Code to read and write OpenSSH private keys, in the old-style PEM
344 OP_DSA, OP_RSA, OP_ECDSA
345 } openssh_pem_keytype;
350 struct openssh_pem_key {
351 openssh_pem_keytype keytype;
353 openssh_pem_enc encryption;
355 unsigned char *keyblob;
356 int keyblob_len, keyblob_size;
359 static struct openssh_pem_key *load_openssh_pem_key(const Filename *filename,
360 const char **errmsg_p)
362 struct openssh_pem_key *ret;
369 int base64_chars = 0;
371 ret = snew(struct openssh_pem_key);
373 ret->keyblob_len = ret->keyblob_size = 0;
375 fp = f_open(filename, "r", FALSE);
377 errmsg = "unable to open key file";
381 if (!(line = fgetline(fp))) {
382 errmsg = "unexpected end of file";
386 if (0 != strncmp(line, "-----BEGIN ", 11) ||
387 0 != strcmp(line+strlen(line)-16, "PRIVATE KEY-----")) {
388 errmsg = "file does not begin with OpenSSH key header";
392 * Parse the BEGIN line. For old-format keys, this tells us the
393 * type of the key; for new-format keys, all it tells us is the
394 * format, and we'll find out the key type once we parse the
397 if (!strcmp(line, "-----BEGIN RSA PRIVATE KEY-----")) {
398 ret->keytype = OP_RSA;
399 } else if (!strcmp(line, "-----BEGIN DSA PRIVATE KEY-----")) {
400 ret->keytype = OP_DSA;
401 } else if (!strcmp(line, "-----BEGIN EC PRIVATE KEY-----")) {
402 ret->keytype = OP_ECDSA;
403 } else if (!strcmp(line, "-----BEGIN OPENSSH PRIVATE KEY-----")) {
404 errmsg = "this is a new-style OpenSSH key";
407 errmsg = "unrecognised key type";
410 smemclr(line, strlen(line));
414 ret->encrypted = FALSE;
415 memset(ret->iv, 0, sizeof(ret->iv));
419 if (!(line = fgetline(fp))) {
420 errmsg = "unexpected end of file";
424 if (0 == strncmp(line, "-----END ", 9) &&
425 0 == strcmp(line+strlen(line)-16, "PRIVATE KEY-----")) {
430 if ((p = strchr(line, ':')) != NULL) {
432 errmsg = "header found in body of key data";
436 while (*p && isspace((unsigned char)*p)) p++;
437 if (!strcmp(line, "Proc-Type")) {
438 if (p[0] != '4' || p[1] != ',') {
439 errmsg = "Proc-Type is not 4 (only 4 is supported)";
443 if (!strcmp(p, "ENCRYPTED"))
444 ret->encrypted = TRUE;
445 } else if (!strcmp(line, "DEK-Info")) {
448 if (!strncmp(p, "DES-EDE3-CBC,", 13)) {
449 ret->encryption = OP_E_3DES;
451 } else if (!strncmp(p, "AES-128-CBC,", 12)) {
452 ret->encryption = OP_E_AES;
455 errmsg = "unsupported cipher";
458 p = strchr(p, ',') + 1;/* always non-NULL, by above checks */
459 for (i = 0; i < ivlen; i++) {
460 if (1 != sscanf(p, "%2x", &j)) {
461 errmsg = "expected more iv data in DEK-Info";
468 errmsg = "more iv data than expected in DEK-Info";
476 while (isbase64(*p)) {
477 base64_bit[base64_chars++] = *p;
478 if (base64_chars == 4) {
479 unsigned char out[3];
484 len = base64_decode_atom(base64_bit, out);
487 errmsg = "invalid base64 encoding";
491 if (ret->keyblob_len + len > ret->keyblob_size) {
492 ret->keyblob_size = ret->keyblob_len + len + 256;
493 ret->keyblob = sresize(ret->keyblob, ret->keyblob_size,
497 memcpy(ret->keyblob + ret->keyblob_len, out, len);
498 ret->keyblob_len += len;
500 smemclr(out, sizeof(out));
506 smemclr(line, strlen(line));
514 if (ret->keyblob_len == 0 || !ret->keyblob) {
515 errmsg = "key body not present";
519 if (ret->encrypted && ret->keyblob_len % 8 != 0) {
520 errmsg = "encrypted key blob is not a multiple of "
525 smemclr(base64_bit, sizeof(base64_bit));
526 if (errmsg_p) *errmsg_p = NULL;
531 smemclr(line, strlen(line));
535 smemclr(base64_bit, sizeof(base64_bit));
538 smemclr(ret->keyblob, ret->keyblob_size);
541 smemclr(ret, sizeof(*ret));
544 if (errmsg_p) *errmsg_p = errmsg;
549 int openssh_pem_encrypted(const Filename *filename)
551 struct openssh_pem_key *key = load_openssh_pem_key(filename, NULL);
556 ret = key->encrypted;
557 smemclr(key->keyblob, key->keyblob_size);
559 smemclr(key, sizeof(*key));
564 struct ssh2_userkey *openssh_pem_read(const Filename *filename,
566 const char **errmsg_p)
568 struct openssh_pem_key *key = load_openssh_pem_key(filename, errmsg_p);
569 struct ssh2_userkey *retkey;
570 unsigned char *p, *q;
571 int ret, id, len, flags;
573 struct ssh2_userkey *retval = NULL;
576 int blobsize = 0, blobptr, privptr;
585 if (key->encrypted) {
587 * Derive encryption key from passphrase and iv/salt:
589 * - let block A equal MD5(passphrase || iv)
590 * - let block B equal MD5(A || passphrase || iv)
591 * - block C would be MD5(B || passphrase || iv) and so on
592 * - encryption key is the first N bytes of A || B
594 * (Note that only 8 bytes of the iv are used for key
595 * derivation, even when the key is encrypted with AES and
596 * hence there are 16 bytes available.)
598 struct MD5Context md5c;
599 unsigned char keybuf[32];
602 MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
603 MD5Update(&md5c, (unsigned char *)key->iv, 8);
604 MD5Final(keybuf, &md5c);
607 MD5Update(&md5c, keybuf, 16);
608 MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
609 MD5Update(&md5c, (unsigned char *)key->iv, 8);
610 MD5Final(keybuf+16, &md5c);
613 * Now decrypt the key blob.
615 if (key->encryption == OP_E_3DES)
616 des3_decrypt_pubkey_ossh(keybuf, (unsigned char *)key->iv,
617 key->keyblob, key->keyblob_len);
620 assert(key->encryption == OP_E_AES);
621 ctx = aes_make_context();
622 aes128_key(ctx, keybuf);
623 aes_iv(ctx, (unsigned char *)key->iv);
624 aes_ssh2_decrypt_blk(ctx, key->keyblob, key->keyblob_len);
625 aes_free_context(ctx);
628 smemclr(&md5c, sizeof(md5c));
629 smemclr(keybuf, sizeof(keybuf));
633 * Now we have a decrypted key blob, which contains an ASN.1
634 * encoded private key. We must now untangle the ASN.1.
636 * We expect the whole key blob to be formatted as a SEQUENCE
637 * (0x30 followed by a length code indicating that the rest of
638 * the blob is part of the sequence). Within that SEQUENCE we
639 * expect to see a bunch of INTEGERs. What those integers mean
640 * depends on the key type:
642 * - For RSA, we expect the integers to be 0, n, e, d, p, q,
643 * dmp1, dmq1, iqmp in that order. (The last three are d mod
644 * (p-1), d mod (q-1), inverse of q mod p respectively.)
646 * - For DSA, we expect them to be 0, p, q, g, y, x in that
649 * - In ECDSA the format is totally different: we see the
650 * SEQUENCE, but beneath is an INTEGER 1, OCTET STRING priv
651 * EXPLICIT [0] OID curve, EXPLICIT [1] BIT STRING pubPoint
656 /* Expect the SEQUENCE header. Take its absence as a failure to
657 * decrypt, if the key was encrypted. */
658 ret = ber_read_id_len(p, key->keyblob_len, &id, &len, &flags);
660 if (ret < 0 || id != 16) {
661 errmsg = "ASN.1 decoding failure";
662 retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
666 /* Expect a load of INTEGERs. */
667 if (key->keytype == OP_RSA)
669 else if (key->keytype == OP_DSA)
672 num_integers = 0; /* placate compiler warnings */
675 if (key->keytype == OP_ECDSA) {
676 /* And now for something completely different */
679 const struct ssh_signkey *alg;
680 const struct ec_curve *curve;
681 int algnamelen, curvenamelen;
683 ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
686 if (ret < 0 || id != 2 || key->keyblob+key->keyblob_len-p < len ||
687 len != 1 || p[0] != 1) {
688 errmsg = "ASN.1 decoding failure";
689 retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
693 /* Read private key OCTET STRING */
694 ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
697 if (ret < 0 || id != 4 || key->keyblob+key->keyblob_len-p < len) {
698 errmsg = "ASN.1 decoding failure";
699 retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
706 ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
709 if (ret < 0 || id != 0 || key->keyblob+key->keyblob_len-p < len) {
710 errmsg = "ASN.1 decoding failure";
711 retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
714 ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
717 if (ret < 0 || id != 6 || key->keyblob+key->keyblob_len-p < len) {
718 errmsg = "ASN.1 decoding failure";
719 retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
722 alg = ec_alg_by_oid(len, p, &curve);
724 errmsg = "Unsupported ECDSA curve.";
729 /* Read BIT STRING point */
730 ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
733 if (ret < 0 || id != 1 || key->keyblob+key->keyblob_len-p < len) {
734 errmsg = "ASN.1 decoding failure";
735 retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
738 ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
741 if (ret < 0 || id != 3 || key->keyblob+key->keyblob_len-p < len ||
742 len != ((((curve->fieldBits + 7) / 8) * 2) + 2)) {
743 errmsg = "ASN.1 decoding failure";
744 retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
747 p += 1; len -= 1; /* Skip 0x00 before point */
749 /* Construct the key */
750 retkey = snew(struct ssh2_userkey);
752 errmsg = "out of memory";
756 blob = snewn((4+19 + 4+8 + 4+len) + (4+1+privlen), unsigned char);
759 errmsg = "out of memory";
765 algnamelen = strlen(alg->name);
766 PUT_32BIT(q, algnamelen); q += 4;
767 memcpy(q, alg->name, algnamelen); q += algnamelen;
769 curvenamelen = strlen(curve->name);
770 PUT_32BIT(q, curvenamelen); q += 4;
771 memcpy(q, curve->name, curvenamelen); q += curvenamelen;
773 PUT_32BIT(q, len); q += 4;
774 memcpy(q, p, len); q += len;
777 * To be acceptable to our createkey(), the private blob must
778 * contain a valid mpint, i.e. without the top bit set. But
779 * the input private string may have the top bit set, so we
780 * prefix a zero byte to ensure createkey() doesn't fail for
783 PUT_32BIT(q, privlen+1);
785 memcpy(q+5, priv, privlen);
787 retkey->data = retkey->alg->createkey(retkey->alg,
793 errmsg = "unable to create key data structure";
797 } else if (key->keytype == OP_RSA || key->keytype == OP_DSA) {
800 * Space to create key blob in.
802 blobsize = 256+key->keyblob_len;
803 blob = snewn(blobsize, unsigned char);
805 if (key->keytype == OP_DSA)
806 memcpy(blob+4, "ssh-dss", 7);
807 else if (key->keytype == OP_RSA)
808 memcpy(blob+4, "ssh-rsa", 7);
812 for (i = 0; i < num_integers; i++) {
813 ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
816 if (ret < 0 || id != 2 ||
817 key->keyblob+key->keyblob_len-p < len) {
818 errmsg = "ASN.1 decoding failure";
819 retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
825 * The first integer should be zero always (I think
826 * this is some sort of version indication).
828 if (len != 1 || p[0] != 0) {
829 errmsg = "version number mismatch";
832 } else if (key->keytype == OP_RSA) {
834 * Integers 1 and 2 go into the public blob but in the
835 * opposite order; integers 3, 4, 5 and 8 go into the
836 * private blob. The other two (6 and 7) are ignored.
839 /* Save the details for after we deal with number 2. */
842 } else if (i != 6 && i != 7) {
843 PUT_32BIT(blob+blobptr, len);
844 memcpy(blob+blobptr+4, p, len);
847 PUT_32BIT(blob+blobptr, modlen);
848 memcpy(blob+blobptr+4, modptr, modlen);
853 } else if (key->keytype == OP_DSA) {
855 * Integers 1-4 go into the public blob; integer 5 goes
856 * into the private blob.
858 PUT_32BIT(blob+blobptr, len);
859 memcpy(blob+blobptr+4, p, len);
865 /* Skip past the number. */
870 * Now put together the actual key. Simplest way to do this is
871 * to assemble our own key blobs and feed them to the createkey
872 * functions; this is a bit faffy but it does mean we get all
873 * the sanity checks for free.
875 assert(privptr > 0); /* should have bombed by now if not */
876 retkey = snew(struct ssh2_userkey);
877 retkey->alg = (key->keytype == OP_RSA ? &ssh_rsa : &ssh_dss);
878 retkey->data = retkey->alg->createkey(retkey->alg, blob, privptr,
883 errmsg = "unable to create key data structure";
888 assert(0 && "Bad key type from load_openssh_pem_key");
889 errmsg = "Bad key type from load_openssh_pem_key";
894 * The old key format doesn't include a comment in the private
897 retkey->comment = dupstr("imported-openssh-key");
899 errmsg = NULL; /* no error */
904 smemclr(blob, blobsize);
907 smemclr(key->keyblob, key->keyblob_size);
909 smemclr(key, sizeof(*key));
911 if (errmsg_p) *errmsg_p = errmsg;
915 int openssh_pem_write(const Filename *filename, struct ssh2_userkey *key,
918 unsigned char *pubblob, *privblob, *spareblob;
919 int publen, privlen, sparelen = 0;
920 unsigned char *outblob;
922 struct mpint_pos numbers[9];
923 int nnumbers, pos, len, seqlen, i;
924 const char *header, *footer;
931 * Fetch the key blobs.
933 pubblob = key->alg->public_blob(key->data, &publen);
934 privblob = key->alg->private_blob(key->data, &privlen);
935 spareblob = outblob = NULL;
941 * Encode the OpenSSH key blob, and also decide on the header
944 if (key->alg == &ssh_rsa || key->alg == &ssh_dss) {
946 * The RSA and DSS handlers share some code because the two
947 * key types have very similar ASN.1 representations, as a
948 * plain SEQUENCE of big integers. So we set up a list of
949 * bignums per key type and then construct the actual blob in
950 * common code after that.
952 if (key->alg == &ssh_rsa) {
954 struct mpint_pos n, e, d, p, q, iqmp, dmp1, dmq1;
955 Bignum bd, bp, bq, bdmp1, bdmq1;
958 * These blobs were generated from inside PuTTY, so we needn't
959 * treat them as untrusted.
961 pos = 4 + GET_32BIT(pubblob);
962 pos += ssh2_read_mpint(pubblob+pos, publen-pos, &e);
963 pos += ssh2_read_mpint(pubblob+pos, publen-pos, &n);
965 pos += ssh2_read_mpint(privblob+pos, privlen-pos, &d);
966 pos += ssh2_read_mpint(privblob+pos, privlen-pos, &p);
967 pos += ssh2_read_mpint(privblob+pos, privlen-pos, &q);
968 pos += ssh2_read_mpint(privblob+pos, privlen-pos, &iqmp);
970 assert(e.start && iqmp.start); /* can't go wrong */
972 /* We also need d mod (p-1) and d mod (q-1). */
973 bd = bignum_from_bytes(d.start, d.bytes);
974 bp = bignum_from_bytes(p.start, p.bytes);
975 bq = bignum_from_bytes(q.start, q.bytes);
978 bdmp1 = bigmod(bd, bp);
979 bdmq1 = bigmod(bd, bq);
984 dmp1.bytes = (bignum_bitcount(bdmp1)+8)/8;
985 dmq1.bytes = (bignum_bitcount(bdmq1)+8)/8;
986 sparelen = dmp1.bytes + dmq1.bytes;
987 spareblob = snewn(sparelen, unsigned char);
988 dmp1.start = spareblob;
989 dmq1.start = spareblob + dmp1.bytes;
990 for (i = 0; i < dmp1.bytes; i++)
991 spareblob[i] = bignum_byte(bdmp1, dmp1.bytes-1 - i);
992 for (i = 0; i < dmq1.bytes; i++)
993 spareblob[i+dmp1.bytes] = bignum_byte(bdmq1, dmq1.bytes-1 - i);
997 numbers[0].start = zero; numbers[0].bytes = 1; zero[0] = '\0';
1008 header = "-----BEGIN RSA PRIVATE KEY-----\n";
1009 footer = "-----END RSA PRIVATE KEY-----\n";
1010 } else { /* ssh-dss */
1012 struct mpint_pos p, q, g, y, x;
1015 * These blobs were generated from inside PuTTY, so we needn't
1016 * treat them as untrusted.
1018 pos = 4 + GET_32BIT(pubblob);
1019 pos += ssh2_read_mpint(pubblob+pos, publen-pos, &p);
1020 pos += ssh2_read_mpint(pubblob+pos, publen-pos, &q);
1021 pos += ssh2_read_mpint(pubblob+pos, publen-pos, &g);
1022 pos += ssh2_read_mpint(pubblob+pos, publen-pos, &y);
1024 pos += ssh2_read_mpint(privblob+pos, privlen-pos, &x);
1026 assert(y.start && x.start); /* can't go wrong */
1028 numbers[0].start = zero; numbers[0].bytes = 1; zero[0] = '\0';
1036 header = "-----BEGIN DSA PRIVATE KEY-----\n";
1037 footer = "-----END DSA PRIVATE KEY-----\n";
1041 * Now count up the total size of the ASN.1 encoded integers,
1042 * so as to determine the length of the containing SEQUENCE.
1045 for (i = 0; i < nnumbers; i++) {
1046 len += ber_write_id_len(NULL, 2, numbers[i].bytes, 0);
1047 len += numbers[i].bytes;
1050 /* Now add on the SEQUENCE header. */
1051 len += ber_write_id_len(NULL, 16, seqlen, ASN1_CONSTRUCTED);
1054 * Now we know how big outblob needs to be. Allocate it.
1056 outblob = snewn(len, unsigned char);
1059 * And write the data into it.
1062 pos += ber_write_id_len(outblob+pos, 16, seqlen, ASN1_CONSTRUCTED);
1063 for (i = 0; i < nnumbers; i++) {
1064 pos += ber_write_id_len(outblob+pos, 2, numbers[i].bytes, 0);
1065 memcpy(outblob+pos, numbers[i].start, numbers[i].bytes);
1066 pos += numbers[i].bytes;
1068 } else if (key->alg == &ssh_ecdsa_nistp256 ||
1069 key->alg == &ssh_ecdsa_nistp384 ||
1070 key->alg == &ssh_ecdsa_nistp521) {
1071 const unsigned char *oid;
1076 * Structure of asn1:
1079 * OCTET STRING (private key)
1083 * BIT STRING (0x00 public key point)
1085 oid = ec_alg_oid(key->alg, &oidlen);
1086 pointlen = (((struct ec_key *)key->data)->publicKey.curve->fieldBits
1089 len = ber_write_id_len(NULL, 2, 1, 0);
1091 len += ber_write_id_len(NULL, 4, privlen - 4, 0);
1093 len += ber_write_id_len(NULL, 0, oidlen +
1094 ber_write_id_len(NULL, 6, oidlen, 0),
1095 ASN1_CLASS_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED);
1096 len += ber_write_id_len(NULL, 6, oidlen, 0);
1098 len += ber_write_id_len(NULL, 1, 2 + pointlen +
1099 ber_write_id_len(NULL, 3, 2 + pointlen, 0),
1100 ASN1_CLASS_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED);
1101 len += ber_write_id_len(NULL, 3, 2 + pointlen, 0);
1102 len += 2 + pointlen;
1105 len += ber_write_id_len(NULL, 16, seqlen, ASN1_CONSTRUCTED);
1107 outblob = snewn(len, unsigned char);
1111 pos += ber_write_id_len(outblob+pos, 16, seqlen, ASN1_CONSTRUCTED);
1112 pos += ber_write_id_len(outblob+pos, 2, 1, 0);
1114 pos += ber_write_id_len(outblob+pos, 4, privlen - 4, 0);
1115 memcpy(outblob+pos, privblob + 4, privlen - 4);
1117 pos += ber_write_id_len(outblob+pos, 0, oidlen +
1118 ber_write_id_len(NULL, 6, oidlen, 0),
1119 ASN1_CLASS_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED);
1120 pos += ber_write_id_len(outblob+pos, 6, oidlen, 0);
1121 memcpy(outblob+pos, oid, oidlen);
1123 pos += ber_write_id_len(outblob+pos, 1, 2 + pointlen +
1124 ber_write_id_len(NULL, 3, 2 + pointlen, 0),
1125 ASN1_CLASS_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED);
1126 pos += ber_write_id_len(outblob+pos, 3, 2 + pointlen, 0);
1128 memcpy(outblob+pos, pubblob+39, 1 + pointlen);
1129 pos += 1 + pointlen;
1131 header = "-----BEGIN EC PRIVATE KEY-----\n";
1132 footer = "-----END EC PRIVATE KEY-----\n";
1134 assert(0); /* zoinks! */
1135 exit(1); /* XXX: GCC doesn't understand assert() on some systems. */
1141 * For the moment, we still encrypt our OpenSSH keys using
1145 struct MD5Context md5c;
1146 unsigned char keybuf[32];
1149 * Round up to the cipher block size, ensuring we have at
1150 * least one byte of padding (see below).
1152 outlen = (len+8) &~ 7;
1154 unsigned char *tmp = snewn(outlen, unsigned char);
1155 memcpy(tmp, outblob, len);
1156 smemclr(outblob, len);
1162 * Padding on OpenSSH keys is deterministic. The number of
1163 * padding bytes is always more than zero, and always at most
1164 * the cipher block length. The value of each padding byte is
1165 * equal to the number of padding bytes. So a plaintext that's
1166 * an exact multiple of the block size will be padded with 08
1167 * 08 08 08 08 08 08 08 (assuming a 64-bit block cipher); a
1168 * plaintext one byte less than a multiple of the block size
1169 * will be padded with just 01.
1171 * This enables the OpenSSL key decryption function to strip
1172 * off the padding algorithmically and return the unpadded
1173 * plaintext to the next layer: it looks at the final byte, and
1174 * then expects to find that many bytes at the end of the data
1175 * with the same value. Those are all removed and the rest is
1179 while (pos < outlen) {
1180 outblob[pos++] = outlen - len;
1184 * Invent an iv. Then derive encryption key from passphrase
1187 * - let block A equal MD5(passphrase || iv)
1188 * - let block B equal MD5(A || passphrase || iv)
1189 * - block C would be MD5(B || passphrase || iv) and so on
1190 * - encryption key is the first N bytes of A || B
1192 for (i = 0; i < 8; i++) iv[i] = random_byte();
1195 MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
1196 MD5Update(&md5c, iv, 8);
1197 MD5Final(keybuf, &md5c);
1200 MD5Update(&md5c, keybuf, 16);
1201 MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
1202 MD5Update(&md5c, iv, 8);
1203 MD5Final(keybuf+16, &md5c);
1206 * Now encrypt the key blob.
1208 des3_encrypt_pubkey_ossh(keybuf, iv, outblob, outlen);
1210 smemclr(&md5c, sizeof(md5c));
1211 smemclr(keybuf, sizeof(keybuf));
1214 * If no encryption, the blob has exactly its original
1221 * And save it. We'll use Unix line endings just in case it's
1222 * subsequently transferred in binary mode.
1224 fp = f_open(filename, "wb", TRUE); /* ensure Unix line endings */
1229 fprintf(fp, "Proc-Type: 4,ENCRYPTED\nDEK-Info: DES-EDE3-CBC,");
1230 for (i = 0; i < 8; i++)
1231 fprintf(fp, "%02X", iv[i]);
1232 fprintf(fp, "\n\n");
1234 base64_encode(fp, outblob, outlen, 64);
1241 smemclr(outblob, outlen);
1245 smemclr(spareblob, sparelen);
1249 smemclr(privblob, privlen);
1253 smemclr(pubblob, publen);
1259 /* ----------------------------------------------------------------------
1260 * Code to read and write OpenSSH private keys in the new-style format.
1264 ON_E_NONE, ON_E_AES256CBC
1265 } openssh_new_cipher;
1267 ON_K_NONE, ON_K_BCRYPT
1270 struct openssh_new_key {
1271 openssh_new_cipher cipher;
1272 openssh_new_kdf kdf;
1276 /* This points to a position within keyblob, not a
1277 * separately allocated thing */
1278 const unsigned char *salt;
1282 int nkeys, key_wanted;
1283 /* This too points to a position within keyblob */
1284 unsigned char *privatestr;
1287 unsigned char *keyblob;
1288 int keyblob_len, keyblob_size;
1291 static struct openssh_new_key *load_openssh_new_key(const Filename *filename,
1292 const char **errmsg_p)
1294 struct openssh_new_key *ret;
1300 int base64_chars = 0;
1301 const void *filedata;
1303 const void *string, *kdfopts, *bcryptsalt, *pubkey;
1304 int stringlen, kdfoptlen, bcryptsaltlen, pubkeylen;
1305 unsigned bcryptrounds, nkeys, key_index;
1307 ret = snew(struct openssh_new_key);
1308 ret->keyblob = NULL;
1309 ret->keyblob_len = ret->keyblob_size = 0;
1311 fp = f_open(filename, "r", FALSE);
1313 errmsg = "unable to open key file";
1317 if (!(line = fgetline(fp))) {
1318 errmsg = "unexpected end of file";
1322 if (0 != strcmp(line, "-----BEGIN OPENSSH PRIVATE KEY-----")) {
1323 errmsg = "file does not begin with OpenSSH new-style key header";
1326 smemclr(line, strlen(line));
1331 if (!(line = fgetline(fp))) {
1332 errmsg = "unexpected end of file";
1336 if (0 == strcmp(line, "-----END OPENSSH PRIVATE KEY-----")) {
1343 while (isbase64(*p)) {
1344 base64_bit[base64_chars++] = *p;
1345 if (base64_chars == 4) {
1346 unsigned char out[3];
1351 len = base64_decode_atom(base64_bit, out);
1354 errmsg = "invalid base64 encoding";
1358 if (ret->keyblob_len + len > ret->keyblob_size) {
1359 ret->keyblob_size = ret->keyblob_len + len + 256;
1360 ret->keyblob = sresize(ret->keyblob, ret->keyblob_size,
1364 memcpy(ret->keyblob + ret->keyblob_len, out, len);
1365 ret->keyblob_len += len;
1367 smemclr(out, sizeof(out));
1372 smemclr(line, strlen(line));
1380 if (ret->keyblob_len == 0 || !ret->keyblob) {
1381 errmsg = "key body not present";
1385 filedata = ret->keyblob;
1386 filelen = ret->keyblob_len;
1388 if (filelen < 15 || 0 != memcmp(filedata, "openssh-key-v1\0", 15)) {
1389 errmsg = "new-style OpenSSH magic number missing\n";
1392 filedata = (const char *)filedata + 15;
1395 if (!(string = get_ssh_string(&filelen, &filedata, &stringlen))) {
1396 errmsg = "encountered EOF before cipher name\n";
1399 if (match_ssh_id(stringlen, string, "none")) {
1400 ret->cipher = ON_E_NONE;
1401 } else if (match_ssh_id(stringlen, string, "aes256-cbc")) {
1402 ret->cipher = ON_E_AES256CBC;
1404 errmsg = "unrecognised cipher name\n";
1408 if (!(string = get_ssh_string(&filelen, &filedata, &stringlen))) {
1409 errmsg = "encountered EOF before kdf name\n";
1412 if (match_ssh_id(stringlen, string, "none")) {
1413 ret->kdf = ON_K_NONE;
1414 } else if (match_ssh_id(stringlen, string, "bcrypt")) {
1415 ret->kdf = ON_K_BCRYPT;
1417 errmsg = "unrecognised kdf name\n";
1421 if (!(kdfopts = get_ssh_string(&filelen, &filedata, &kdfoptlen))) {
1422 errmsg = "encountered EOF before kdf options\n";
1427 if (kdfoptlen != 0) {
1428 errmsg = "expected empty options string for 'none' kdf";
1433 if (!(bcryptsalt = get_ssh_string(&kdfoptlen, &kdfopts,
1435 errmsg = "bcrypt options string did not contain salt\n";
1438 if (!get_ssh_uint32(&kdfoptlen, &kdfopts, &bcryptrounds)) {
1439 errmsg = "bcrypt options string did not contain round count\n";
1442 ret->kdfopts.bcrypt.salt = bcryptsalt;
1443 ret->kdfopts.bcrypt.saltlen = bcryptsaltlen;
1444 ret->kdfopts.bcrypt.rounds = bcryptrounds;
1449 * At this point we expect a uint32 saying how many keys are
1450 * stored in this file. OpenSSH new-style key files can
1451 * contain more than one. Currently we don't have any user
1452 * interface to specify which one we're trying to extract, so
1453 * we just bomb out with an error if more than one is found in
1454 * the file. However, I've put in all the mechanism here to
1455 * extract the nth one for a given n, in case we later connect
1456 * up some UI to that mechanism. Just arrange that the
1457 * 'key_wanted' field is set to a value in the range [0,
1458 * nkeys) by some mechanism.
1460 if (!get_ssh_uint32(&filelen, &filedata, &nkeys)) {
1461 errmsg = "encountered EOF before key count\n";
1465 errmsg = "multiple keys in new-style OpenSSH key file "
1470 ret->key_wanted = 0;
1472 for (key_index = 0; key_index < nkeys; key_index++) {
1473 if (!(pubkey = get_ssh_string(&filelen, &filedata, &pubkeylen))) {
1474 errmsg = "encountered EOF before kdf options\n";
1480 * Now we expect a string containing the encrypted part of the
1483 if (!(string = get_ssh_string(&filelen, &filedata, &stringlen))) {
1484 errmsg = "encountered EOF before private key container\n";
1487 ret->privatestr = (unsigned char *)string;
1488 ret->privatelen = stringlen;
1491 * And now we're done, until asked to actually decrypt.
1494 smemclr(base64_bit, sizeof(base64_bit));
1495 if (errmsg_p) *errmsg_p = NULL;
1500 smemclr(line, strlen(line));
1504 smemclr(base64_bit, sizeof(base64_bit));
1507 smemclr(ret->keyblob, ret->keyblob_size);
1508 sfree(ret->keyblob);
1510 smemclr(ret, sizeof(*ret));
1513 if (errmsg_p) *errmsg_p = errmsg;
1518 int openssh_new_encrypted(const Filename *filename)
1520 struct openssh_new_key *key = load_openssh_new_key(filename, NULL);
1525 ret = (key->cipher != ON_E_NONE);
1526 smemclr(key->keyblob, key->keyblob_size);
1527 sfree(key->keyblob);
1528 smemclr(key, sizeof(*key));
1533 struct ssh2_userkey *openssh_new_read(const Filename *filename,
1535 const char **errmsg_p)
1537 struct openssh_new_key *key = load_openssh_new_key(filename, errmsg_p);
1538 struct ssh2_userkey *retkey;
1540 struct ssh2_userkey *retval = NULL;
1542 unsigned char *blob;
1544 unsigned checkint0, checkint1;
1545 const void *priv, *string;
1546 int privlen, stringlen, key_index;
1547 const struct ssh_signkey *alg;
1554 if (key->cipher != ON_E_NONE) {
1555 unsigned char keybuf[48];
1559 * Construct the decryption key, and decrypt the string.
1561 switch (key->cipher) {
1565 case ON_E_AES256CBC:
1566 keysize = 48; /* 32 byte key + 16 byte IV */
1569 assert(0 && "Bad cipher enumeration value");
1571 assert(keysize <= sizeof(keybuf));
1574 memset(keybuf, 0, keysize);
1577 openssh_bcrypt(passphrase,
1578 key->kdfopts.bcrypt.salt,
1579 key->kdfopts.bcrypt.saltlen,
1580 key->kdfopts.bcrypt.rounds,
1584 assert(0 && "Bad kdf enumeration value");
1586 switch (key->cipher) {
1589 case ON_E_AES256CBC:
1590 if (key->privatelen % 16 != 0) {
1591 errmsg = "private key container length is not a"
1592 " multiple of AES block size\n";
1596 void *ctx = aes_make_context();
1597 aes256_key(ctx, keybuf);
1598 aes_iv(ctx, keybuf + 32);
1599 aes_ssh2_decrypt_blk(ctx, key->privatestr,
1601 aes_free_context(ctx);
1605 assert(0 && "Bad cipher enumeration value");
1610 * Now parse the entire encrypted section, and extract the key
1611 * identified by key_wanted.
1613 priv = key->privatestr;
1614 privlen = key->privatelen;
1616 if (!get_ssh_uint32(&privlen, &priv, &checkint0) ||
1617 !get_ssh_uint32(&privlen, &priv, &checkint1) ||
1618 checkint0 != checkint1) {
1619 errmsg = "decryption check failed";
1624 for (key_index = 0; key_index < key->nkeys; key_index++) {
1625 const unsigned char *thiskey;
1629 * Read the key type, which will tell us how to scan over
1630 * the key to get to the next one.
1632 if (!(string = get_ssh_string(&privlen, &priv, &stringlen))) {
1633 errmsg = "expected key type in private string";
1638 * Preliminary key type identification, and decide how
1639 * many pieces of key we expect to see. Currently
1640 * (conveniently) all key types can be seen as some number
1641 * of strings, so we just need to know how many of them to
1642 * skip over. (The numbers below exclude the key comment.)
1645 /* find_pubkey_alg needs a zero-terminated copy of the
1647 char *name_zt = dupprintf("%.*s", stringlen, (char *)string);
1648 alg = find_pubkey_alg(name_zt);
1653 errmsg = "private key type not recognised\n";
1660 * Skip over the pieces of key.
1662 for (i = 0; i < alg->openssh_private_npieces; i++) {
1663 if (!(string = get_ssh_string(&privlen, &priv, &stringlen))) {
1664 errmsg = "ran out of data in mid-private-key";
1669 thiskeylen = (int)((const unsigned char *)priv -
1670 (const unsigned char *)thiskey);
1671 if (key_index == key->key_wanted) {
1672 retkey = snew(struct ssh2_userkey);
1674 retkey->data = alg->openssh_createkey(alg, &thiskey, &thiskeylen);
1675 if (!retkey->data) {
1677 errmsg = "unable to create key data structure";
1683 * Read the key comment.
1685 if (!(string = get_ssh_string(&privlen, &priv, &stringlen))) {
1686 errmsg = "ran out of data at key comment";
1689 if (key_index == key->key_wanted) {
1691 retkey->comment = dupprintf("%.*s", stringlen,
1692 (const char *)string);
1697 errmsg = "key index out of range";
1702 * Now we expect nothing left but padding.
1704 for (i = 0; i < privlen; i++) {
1705 if (((const unsigned char *)priv)[i] != (unsigned char)(i+1)) {
1706 errmsg = "padding at end of private string did not match";
1711 errmsg = NULL; /* no error */
1716 smemclr(blob, blobsize);
1719 smemclr(key->keyblob, key->keyblob_size);
1720 sfree(key->keyblob);
1721 smemclr(key, sizeof(*key));
1723 if (errmsg_p) *errmsg_p = errmsg;
1727 int openssh_new_write(const Filename *filename, struct ssh2_userkey *key,
1730 unsigned char *pubblob, *privblob, *outblob, *p;
1731 unsigned char *private_section_start, *private_section_length_field;
1732 int publen, privlen, commentlen, maxsize, padvalue, i;
1735 unsigned char bcrypt_salt[16];
1736 const int bcrypt_rounds = 16;
1740 * Fetch the key blobs and find out the lengths of things.
1742 pubblob = key->alg->public_blob(key->data, &publen);
1743 i = key->alg->openssh_fmtkey(key->data, NULL, 0);
1744 privblob = snewn(i, unsigned char);
1745 privlen = key->alg->openssh_fmtkey(key->data, privblob, i);
1746 assert(privlen == i);
1747 commentlen = strlen(key->comment);
1750 * Allocate enough space for the full binary key format. No need
1751 * to be absolutely precise here.
1753 maxsize = (16 + /* magic number */
1754 32 + /* cipher name string */
1755 32 + /* kdf name string */
1756 64 + /* kdf options string */
1758 4+publen + /* public key string */
1759 4 + /* string header for private section */
1760 8 + /* checkint x 2 */
1761 4+strlen(key->alg->name) + /* key type string */
1762 privlen + /* private blob */
1763 4+commentlen + /* comment string */
1764 16); /* padding at end of private section */
1765 outblob = snewn(maxsize, unsigned char);
1768 * Construct the cleartext version of the blob.
1773 memcpy(p, "openssh-key-v1\0", 15);
1776 /* Cipher and kdf names, and kdf options. */
1778 memset(bcrypt_salt, 0, sizeof(bcrypt_salt)); /* prevent warnings */
1779 p += put_string_z(p, "none");
1780 p += put_string_z(p, "none");
1781 p += put_string_z(p, "");
1784 for (i = 0; i < (int)sizeof(bcrypt_salt); i++)
1785 bcrypt_salt[i] = random_byte();
1786 p += put_string_z(p, "aes256-cbc");
1787 p += put_string_z(p, "bcrypt");
1790 p += put_string(p, bcrypt_salt, sizeof(bcrypt_salt));
1791 p += put_uint32(p, bcrypt_rounds);
1792 PUT_32BIT_MSB_FIRST(q, (unsigned)(p - (q+4)));
1795 /* Number of keys. */
1796 p += put_uint32(p, 1);
1799 p += put_string(p, pubblob, publen);
1801 /* Begin private section. */
1802 private_section_length_field = p;
1804 private_section_start = p;
1808 for (i = 0; i < 4; i++)
1809 checkint = (checkint << 8) + random_byte();
1810 p += put_uint32(p, checkint);
1811 p += put_uint32(p, checkint);
1813 /* Private key. The main private blob goes inline, with no string
1815 p += put_string_z(p, key->alg->name);
1816 memcpy(p, privblob, privlen);
1820 p += put_string_z(p, key->comment);
1822 /* Pad out the encrypted section. */
1826 } while ((p - private_section_start) & 15);
1828 assert(p - outblob < maxsize);
1830 /* Go back and fill in the length field for the private section. */
1831 PUT_32BIT_MSB_FIRST(private_section_length_field,
1832 p - private_section_start);
1836 * Encrypt the private section. We need 48 bytes of key
1837 * material: 32 bytes AES key + 16 bytes iv.
1839 unsigned char keybuf[48];
1842 openssh_bcrypt(passphrase,
1843 bcrypt_salt, sizeof(bcrypt_salt), bcrypt_rounds,
1844 keybuf, sizeof(keybuf));
1846 ctx = aes_make_context();
1847 aes256_key(ctx, keybuf);
1848 aes_iv(ctx, keybuf + 32);
1849 aes_ssh2_encrypt_blk(ctx, private_section_start,
1850 p - private_section_start);
1851 aes_free_context(ctx);
1853 smemclr(keybuf, sizeof(keybuf));
1857 * And save it. We'll use Unix line endings just in case it's
1858 * subsequently transferred in binary mode.
1860 fp = f_open(filename, "wb", TRUE); /* ensure Unix line endings */
1863 fputs("-----BEGIN OPENSSH PRIVATE KEY-----\n", fp);
1864 base64_encode(fp, outblob, p - outblob, 64);
1865 fputs("-----END OPENSSH PRIVATE KEY-----\n", fp);
1871 smemclr(outblob, maxsize);
1875 smemclr(privblob, privlen);
1879 smemclr(pubblob, publen);
1885 /* ----------------------------------------------------------------------
1886 * The switch function openssh_auto_write(), which chooses one of the
1887 * concrete OpenSSH output formats based on the key type.
1889 int openssh_auto_write(const Filename *filename, struct ssh2_userkey *key,
1893 * The old OpenSSH format supports a fixed list of key types. We
1894 * assume that anything not in that fixed list is newer, and hence
1895 * will use the new format.
1897 if (key->alg == &ssh_dss ||
1898 key->alg == &ssh_rsa ||
1899 key->alg == &ssh_ecdsa_nistp256 ||
1900 key->alg == &ssh_ecdsa_nistp384 ||
1901 key->alg == &ssh_ecdsa_nistp521)
1902 return openssh_pem_write(filename, key, passphrase);
1904 return openssh_new_write(filename, key, passphrase);
1907 /* ----------------------------------------------------------------------
1908 * Code to read ssh.com private keys.
1912 * The format of the base64 blob is largely SSH-2-packet-formatted,
1913 * except that mpints are a bit different: they're more like the
1914 * old SSH-1 mpint. You have a 32-bit bit count N, followed by
1915 * (N+7)/8 bytes of data.
1917 * So. The blob contains:
1919 * - uint32 0x3f6ff9eb (magic number)
1920 * - uint32 size (total blob size)
1921 * - string key-type (see below)
1922 * - string cipher-type (tells you if key is encrypted)
1923 * - string encrypted-blob
1925 * (The first size field includes the size field itself and the
1926 * magic number before it. All other size fields are ordinary SSH-2
1927 * strings, so the size field indicates how much data is to
1930 * The encrypted blob, once decrypted, contains a single string
1931 * which in turn contains the payload. (This allows padding to be
1932 * added after that string while still making it clear where the
1933 * real payload ends. Also it probably makes for a reasonable
1934 * decryption check.)
1936 * The payload blob, for an RSA key, contains:
1939 * - mpint n (yes, the public and private stuff is intermixed)
1940 * - mpint u (presumably inverse of p mod q)
1941 * - mpint p (p is the smaller prime)
1942 * - mpint q (q is the larger)
1944 * For a DSA key, the payload blob contains:
1952 * Alternatively, if the parameters are `predefined', that
1953 * (0,p,g,q) sequence can be replaced by a uint32 1 and a string
1954 * containing some predefined parameter specification. *shudder*,
1955 * but I doubt we'll encounter this in real life.
1957 * The key type strings are ghastly. The RSA key I looked at had a
1960 * `if-modn{sign{rsa-pkcs1-sha1},encrypt{rsa-pkcs1v2-oaep}}'
1962 * and the DSA key wasn't much better:
1964 * `dl-modp{sign{dsa-nist-sha1},dh{plain}}'
1966 * It isn't clear that these will always be the same. I think it
1967 * might be wise just to look at the `if-modn{sign{rsa' and
1968 * `dl-modp{sign{dsa' prefixes.
1970 * Finally, the encryption. The cipher-type string appears to be
1971 * either `none' or `3des-cbc'. Looks as if this is SSH-2-style
1972 * 3des-cbc (i.e. outer cbc rather than inner). The key is created
1973 * from the passphrase by means of yet another hashing faff:
1975 * - first 16 bytes are MD5(passphrase)
1976 * - next 16 bytes are MD5(passphrase || first 16 bytes)
1977 * - if there were more, they'd be MD5(passphrase || first 32),
1981 #define SSHCOM_MAGIC_NUMBER 0x3f6ff9eb
1984 char comment[256]; /* allowing any length is overkill */
1985 unsigned char *keyblob;
1986 int keyblob_len, keyblob_size;
1989 static struct sshcom_key *load_sshcom_key(const Filename *filename,
1990 const char **errmsg_p)
1992 struct sshcom_key *ret;
2000 int base64_chars = 0;
2002 ret = snew(struct sshcom_key);
2003 ret->comment[0] = '\0';
2004 ret->keyblob = NULL;
2005 ret->keyblob_len = ret->keyblob_size = 0;
2007 fp = f_open(filename, "r", FALSE);
2009 errmsg = "unable to open key file";
2012 if (!(line = fgetline(fp))) {
2013 errmsg = "unexpected end of file";
2017 if (0 != strcmp(line, "---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----")) {
2018 errmsg = "file does not begin with ssh.com key header";
2021 smemclr(line, strlen(line));
2027 if (!(line = fgetline(fp))) {
2028 errmsg = "unexpected end of file";
2032 if (!strcmp(line, "---- END SSH2 ENCRYPTED PRIVATE KEY ----")) {
2037 if ((p = strchr(line, ':')) != NULL) {
2039 errmsg = "header found in body of key data";
2043 while (*p && isspace((unsigned char)*p)) p++;
2044 hdrstart = p - line;
2047 * Header lines can end in a trailing backslash for
2050 len = hdrstart + strlen(line+hdrstart);
2052 while (line[len-1] == '\\') {
2056 line2 = fgetline(fp);
2058 errmsg = "unexpected end of file";
2063 line2len = strlen(line2);
2064 line = sresize(line, len + line2len + 1, char);
2065 strcpy(line + len - 1, line2);
2066 len += line2len - 1;
2069 smemclr(line2, strlen(line2));
2073 p = line + hdrstart;
2075 if (!strcmp(line, "Comment")) {
2076 /* Strip quotes in comment if present. */
2077 if (p[0] == '"' && p[strlen(p)-1] == '"') {
2079 p[strlen(p)-1] = '\0';
2081 strncpy(ret->comment, p, sizeof(ret->comment));
2082 ret->comment[sizeof(ret->comment)-1] = '\0';
2088 while (isbase64(*p)) {
2089 base64_bit[base64_chars++] = *p;
2090 if (base64_chars == 4) {
2091 unsigned char out[3];
2095 len = base64_decode_atom(base64_bit, out);
2098 errmsg = "invalid base64 encoding";
2102 if (ret->keyblob_len + len > ret->keyblob_size) {
2103 ret->keyblob_size = ret->keyblob_len + len + 256;
2104 ret->keyblob = sresize(ret->keyblob, ret->keyblob_size,
2108 memcpy(ret->keyblob + ret->keyblob_len, out, len);
2109 ret->keyblob_len += len;
2115 smemclr(line, strlen(line));
2120 if (ret->keyblob_len == 0 || !ret->keyblob) {
2121 errmsg = "key body not present";
2126 if (errmsg_p) *errmsg_p = NULL;
2134 smemclr(line, strlen(line));
2140 smemclr(ret->keyblob, ret->keyblob_size);
2141 sfree(ret->keyblob);
2143 smemclr(ret, sizeof(*ret));
2146 if (errmsg_p) *errmsg_p = errmsg;
2150 int sshcom_encrypted(const Filename *filename, char **comment)
2152 struct sshcom_key *key = load_sshcom_key(filename, NULL);
2153 int pos, len, answer;
2162 * Check magic number.
2164 if (GET_32BIT(key->keyblob) != 0x3f6ff9eb) {
2165 goto done; /* key is invalid */
2169 * Find the cipher-type string.
2172 if (key->keyblob_len < pos+4)
2173 goto done; /* key is far too short */
2174 len = toint(GET_32BIT(key->keyblob + pos));
2175 if (len < 0 || len > key->keyblob_len - pos - 4)
2176 goto done; /* key is far too short */
2177 pos += 4 + len; /* skip key type */
2178 len = toint(GET_32BIT(key->keyblob + pos)); /* find cipher-type length */
2179 if (len < 0 || len > key->keyblob_len - pos - 4)
2180 goto done; /* cipher type string is incomplete */
2181 if (len != 4 || 0 != memcmp(key->keyblob + pos + 4, "none", 4))
2186 *comment = dupstr(key->comment);
2187 smemclr(key->keyblob, key->keyblob_size);
2188 sfree(key->keyblob);
2189 smemclr(key, sizeof(*key));
2192 *comment = dupstr("");
2197 static int sshcom_read_mpint(void *data, int len, struct mpint_pos *ret)
2199 unsigned bits, bytes;
2200 unsigned char *d = (unsigned char *) data;
2204 bits = GET_32BIT(d);
2206 bytes = (bits + 7) / 8;
2217 return len; /* ensure further calls fail as well */
2220 static int sshcom_put_mpint(void *target, void *data, int len)
2222 unsigned char *d = (unsigned char *)target;
2223 unsigned char *i = (unsigned char *)data;
2224 int bits = len * 8 - 1;
2227 if (*i & (1 << (bits & 7)))
2233 PUT_32BIT(d, bits+1);
2234 memcpy(d+4, i, len);
2238 struct ssh2_userkey *sshcom_read(const Filename *filename, char *passphrase,
2239 const char **errmsg_p)
2241 struct sshcom_key *key = load_sshcom_key(filename, errmsg_p);
2244 const char prefix_rsa[] = "if-modn{sign{rsa";
2245 const char prefix_dsa[] = "dl-modp{sign{dsa";
2246 enum { RSA, DSA } type;
2250 struct ssh2_userkey *ret = NULL, *retkey;
2251 const struct ssh_signkey *alg;
2252 unsigned char *blob = NULL;
2253 int blobsize = 0, publen, privlen;
2259 * Check magic number.
2261 if (GET_32BIT(key->keyblob) != SSHCOM_MAGIC_NUMBER) {
2262 errmsg = "key does not begin with magic number";
2267 * Determine the key type.
2270 if (key->keyblob_len < pos+4 ||
2271 (len = toint(GET_32BIT(key->keyblob + pos))) < 0 ||
2272 len > key->keyblob_len - pos - 4) {
2273 errmsg = "key blob does not contain a key type string";
2276 if (len > sizeof(prefix_rsa) - 1 &&
2277 !memcmp(key->keyblob+pos+4, prefix_rsa, sizeof(prefix_rsa) - 1)) {
2279 } else if (len > sizeof(prefix_dsa) - 1 &&
2280 !memcmp(key->keyblob+pos+4, prefix_dsa, sizeof(prefix_dsa) - 1)) {
2283 errmsg = "key is of unknown type";
2289 * Determine the cipher type.
2291 if (key->keyblob_len < pos+4 ||
2292 (len = toint(GET_32BIT(key->keyblob + pos))) < 0 ||
2293 len > key->keyblob_len - pos - 4) {
2294 errmsg = "key blob does not contain a cipher type string";
2297 if (len == 4 && !memcmp(key->keyblob+pos+4, "none", 4))
2299 else if (len == 8 && !memcmp(key->keyblob+pos+4, "3des-cbc", 8))
2302 errmsg = "key encryption is of unknown type";
2308 * Get hold of the encrypted part of the key.
2310 if (key->keyblob_len < pos+4 ||
2311 (len = toint(GET_32BIT(key->keyblob + pos))) < 0 ||
2312 len > key->keyblob_len - pos - 4) {
2313 errmsg = "key blob does not contain actual key data";
2316 ciphertext = (char *)key->keyblob + pos + 4;
2318 if (cipherlen == 0) {
2319 errmsg = "length of key data is zero";
2324 * Decrypt it if necessary.
2328 * Derive encryption key from passphrase and iv/salt:
2330 * - let block A equal MD5(passphrase)
2331 * - let block B equal MD5(passphrase || A)
2332 * - block C would be MD5(passphrase || A || B) and so on
2333 * - encryption key is the first N bytes of A || B
2335 struct MD5Context md5c;
2336 unsigned char keybuf[32], iv[8];
2338 if (cipherlen % 8 != 0) {
2339 errmsg = "encrypted part of key is not a multiple of cipher block"
2345 MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
2346 MD5Final(keybuf, &md5c);
2349 MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
2350 MD5Update(&md5c, keybuf, 16);
2351 MD5Final(keybuf+16, &md5c);
2354 * Now decrypt the key blob.
2356 memset(iv, 0, sizeof(iv));
2357 des3_decrypt_pubkey_ossh(keybuf, iv, (unsigned char *)ciphertext,
2360 smemclr(&md5c, sizeof(md5c));
2361 smemclr(keybuf, sizeof(keybuf));
2364 * Hereafter we return WRONG_PASSPHRASE for any parsing
2365 * error. (But only if we've just tried to decrypt it!
2366 * Returning WRONG_PASSPHRASE for an unencrypted key is
2370 ret = SSH2_WRONG_PASSPHRASE;
2374 * Strip away the containing string to get to the real meat.
2376 len = toint(GET_32BIT(ciphertext));
2377 if (len < 0 || len > cipherlen-4) {
2378 errmsg = "containing string was ill-formed";
2385 * Now we break down into RSA versus DSA. In either case we'll
2386 * construct public and private blobs in our own format, and
2387 * end up feeding them to alg->createkey().
2389 blobsize = cipherlen + 256;
2390 blob = snewn(blobsize, unsigned char);
2393 struct mpint_pos n, e, d, u, p, q;
2395 pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &e);
2396 pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &d);
2397 pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &n);
2398 pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &u);
2399 pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &p);
2400 pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &q);
2402 errmsg = "key data did not contain six integers";
2408 pos += put_string(blob+pos, "ssh-rsa", 7);
2409 pos += put_mp(blob+pos, e.start, e.bytes);
2410 pos += put_mp(blob+pos, n.start, n.bytes);
2412 pos += put_string(blob+pos, d.start, d.bytes);
2413 pos += put_mp(blob+pos, q.start, q.bytes);
2414 pos += put_mp(blob+pos, p.start, p.bytes);
2415 pos += put_mp(blob+pos, u.start, u.bytes);
2416 privlen = pos - publen;
2418 struct mpint_pos p, q, g, x, y;
2421 assert(type == DSA); /* the only other option from the if above */
2423 if (GET_32BIT(ciphertext) != 0) {
2424 errmsg = "predefined DSA parameters not supported";
2427 pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &p);
2428 pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &g);
2429 pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &q);
2430 pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &y);
2431 pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &x);
2433 errmsg = "key data did not contain five integers";
2439 pos += put_string(blob+pos, "ssh-dss", 7);
2440 pos += put_mp(blob+pos, p.start, p.bytes);
2441 pos += put_mp(blob+pos, q.start, q.bytes);
2442 pos += put_mp(blob+pos, g.start, g.bytes);
2443 pos += put_mp(blob+pos, y.start, y.bytes);
2445 pos += put_mp(blob+pos, x.start, x.bytes);
2446 privlen = pos - publen;
2449 assert(privlen > 0); /* should have bombed by now if not */
2451 retkey = snew(struct ssh2_userkey);
2453 retkey->data = alg->createkey(alg, blob, publen, blob+publen, privlen);
2454 if (!retkey->data) {
2456 errmsg = "unable to create key data structure";
2459 retkey->comment = dupstr(key->comment);
2461 errmsg = NULL; /* no error */
2466 smemclr(blob, blobsize);
2469 smemclr(key->keyblob, key->keyblob_size);
2470 sfree(key->keyblob);
2471 smemclr(key, sizeof(*key));
2473 if (errmsg_p) *errmsg_p = errmsg;
2477 int sshcom_write(const Filename *filename, struct ssh2_userkey *key,
2480 unsigned char *pubblob, *privblob;
2481 int publen, privlen;
2482 unsigned char *outblob;
2484 struct mpint_pos numbers[6];
2485 int nnumbers, initial_zero, pos, lenpos, i;
2493 * Fetch the key blobs.
2495 pubblob = key->alg->public_blob(key->data, &publen);
2496 privblob = key->alg->private_blob(key->data, &privlen);
2500 * Find the sequence of integers to be encoded into the OpenSSH
2501 * key blob, and also decide on the header line.
2503 if (key->alg == &ssh_rsa) {
2505 struct mpint_pos n, e, d, p, q, iqmp;
2508 * These blobs were generated from inside PuTTY, so we needn't
2509 * treat them as untrusted.
2511 pos = 4 + GET_32BIT(pubblob);
2512 pos += ssh2_read_mpint(pubblob+pos, publen-pos, &e);
2513 pos += ssh2_read_mpint(pubblob+pos, publen-pos, &n);
2515 pos += ssh2_read_mpint(privblob+pos, privlen-pos, &d);
2516 pos += ssh2_read_mpint(privblob+pos, privlen-pos, &p);
2517 pos += ssh2_read_mpint(privblob+pos, privlen-pos, &q);
2518 pos += ssh2_read_mpint(privblob+pos, privlen-pos, &iqmp);
2520 assert(e.start && iqmp.start); /* can't go wrong */
2531 type = "if-modn{sign{rsa-pkcs1-sha1},encrypt{rsa-pkcs1v2-oaep}}";
2532 } else if (key->alg == &ssh_dss) {
2534 struct mpint_pos p, q, g, y, x;
2537 * These blobs were generated from inside PuTTY, so we needn't
2538 * treat them as untrusted.
2540 pos = 4 + GET_32BIT(pubblob);
2541 pos += ssh2_read_mpint(pubblob+pos, publen-pos, &p);
2542 pos += ssh2_read_mpint(pubblob+pos, publen-pos, &q);
2543 pos += ssh2_read_mpint(pubblob+pos, publen-pos, &g);
2544 pos += ssh2_read_mpint(pubblob+pos, publen-pos, &y);
2546 pos += ssh2_read_mpint(privblob+pos, privlen-pos, &x);
2548 assert(y.start && x.start); /* can't go wrong */
2558 type = "dl-modp{sign{dsa-nist-sha1},dh{plain}}";
2560 assert(0); /* zoinks! */
2561 exit(1); /* XXX: GCC doesn't understand assert() on some systems. */
2565 * Total size of key blob will be somewhere under 512 plus
2566 * combined length of integers. We'll calculate the more
2567 * precise size as we construct the blob.
2570 for (i = 0; i < nnumbers; i++)
2571 outlen += 4 + numbers[i].bytes;
2572 outblob = snewn(outlen, unsigned char);
2575 * Create the unencrypted key blob.
2578 PUT_32BIT(outblob+pos, SSHCOM_MAGIC_NUMBER); pos += 4;
2579 pos += 4; /* length field, fill in later */
2580 pos += put_string(outblob+pos, type, strlen(type));
2582 const char *ciphertype = passphrase ? "3des-cbc" : "none";
2583 pos += put_string(outblob+pos, ciphertype, strlen(ciphertype));
2585 lenpos = pos; /* remember this position */
2586 pos += 4; /* encrypted-blob size */
2587 pos += 4; /* encrypted-payload size */
2589 PUT_32BIT(outblob+pos, 0);
2592 for (i = 0; i < nnumbers; i++)
2593 pos += sshcom_put_mpint(outblob+pos,
2594 numbers[i].start, numbers[i].bytes);
2595 /* Now wrap up the encrypted payload. */
2596 PUT_32BIT(outblob+lenpos+4, pos - (lenpos+8));
2597 /* Pad encrypted blob to a multiple of cipher block size. */
2599 int padding = -(pos - (lenpos+4)) & 7;
2601 outblob[pos++] = random_byte();
2603 ciphertext = (char *)outblob+lenpos+4;
2604 cipherlen = pos - (lenpos+4);
2605 assert(!passphrase || cipherlen % 8 == 0);
2606 /* Wrap up the encrypted blob string. */
2607 PUT_32BIT(outblob+lenpos, cipherlen);
2608 /* And finally fill in the total length field. */
2609 PUT_32BIT(outblob+4, pos);
2611 assert(pos < outlen);
2618 * Derive encryption key from passphrase and iv/salt:
2620 * - let block A equal MD5(passphrase)
2621 * - let block B equal MD5(passphrase || A)
2622 * - block C would be MD5(passphrase || A || B) and so on
2623 * - encryption key is the first N bytes of A || B
2625 struct MD5Context md5c;
2626 unsigned char keybuf[32], iv[8];
2629 MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
2630 MD5Final(keybuf, &md5c);
2633 MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
2634 MD5Update(&md5c, keybuf, 16);
2635 MD5Final(keybuf+16, &md5c);
2638 * Now decrypt the key blob.
2640 memset(iv, 0, sizeof(iv));
2641 des3_encrypt_pubkey_ossh(keybuf, iv, (unsigned char *)ciphertext,
2644 smemclr(&md5c, sizeof(md5c));
2645 smemclr(keybuf, sizeof(keybuf));
2649 * And save it. We'll use Unix line endings just in case it's
2650 * subsequently transferred in binary mode.
2652 fp = f_open(filename, "wb", TRUE); /* ensure Unix line endings */
2655 fputs("---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----\n", fp);
2656 fprintf(fp, "Comment: \"");
2658 * Comment header is broken with backslash-newline if it goes
2659 * over 70 chars. Although it's surrounded by quotes, it
2660 * _doesn't_ escape backslashes or quotes within the string.
2661 * Don't ask me, I didn't design it.
2664 int slen = 60; /* starts at 60 due to "Comment: " */
2665 char *c = key->comment;
2666 while ((int)strlen(c) > slen) {
2667 fprintf(fp, "%.*s\\\n", slen, c);
2669 slen = 70; /* allow 70 chars on subsequent lines */
2671 fprintf(fp, "%s\"\n", c);
2673 base64_encode(fp, outblob, pos, 70);
2674 fputs("---- END SSH2 ENCRYPTED PRIVATE KEY ----\n", fp);
2680 smemclr(outblob, outlen);
2684 smemclr(privblob, privlen);
2688 smemclr(pubblob, publen);