2 * Generic SSH public-key handling operations. In particular,
3 * reading of SSH public-key files, and also the generic `sign'
4 * operation for ssh2 (which checks the type of the key and
5 * dispatches to the appropriate key-type specific function).
16 #define PUT_32BIT(cp, value) do { \
18 (cp)[2] = (value) >> 8; \
19 (cp)[1] = (value) >> 16; \
20 (cp)[0] = (value) >> 24; } while (0)
22 #define GET_32BIT(cp) \
23 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
24 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
25 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
26 ((unsigned long)(unsigned char)(cp)[3]))
28 #define rsa_signature "SSH PRIVATE KEY FILE FORMAT 1.1\n"
30 #define BASE64_TOINT(x) ( (x)-'A'<26 ? (x)-'A'+0 :\
31 (x)-'a'<26 ? (x)-'a'+26 :\
32 (x)-'0'<10 ? (x)-'0'+52 :\
36 static int loadrsakey_main(FILE * fp, struct RSAKey *key, int pub_only,
37 char **commentptr, char *passphrase,
40 unsigned char buf[16384];
41 unsigned char keybuf[16];
45 struct MD5Context md5c;
50 /* Slurp the whole file (minus the header) into a buffer. */
51 len = fread(buf, 1, sizeof(buf), fp);
53 if (len < 0 || len == sizeof(buf)) {
54 *error = "error reading file";
55 goto end; /* file too big or not read */
59 *error = "file format error";
62 * A zero byte. (The signature includes a terminating NUL.)
64 if (len - i < 1 || buf[i] != 0)
68 /* One byte giving encryption type, and one reserved uint32. */
72 if (ciphertype != 0 && ciphertype != SSH_CIPHER_3DES)
76 goto end; /* reserved field not present */
77 if (buf[i] != 0 || buf[i + 1] != 0 || buf[i + 2] != 0
78 || buf[i + 3] != 0) goto end; /* reserved field nonzero, panic! */
81 /* Now the serious stuff. An ordinary SSH 1 public key. */
82 i += makekey(buf + i, key, NULL, 1);
84 goto end; /* overran */
91 /* Next, the comment field. */
92 j = GET_32BIT(buf + i);
96 comment = snewn(j + 1, char);
98 memcpy(comment, buf + i, j);
103 *commentptr = comment;
105 key->comment = comment;
107 ret = ciphertype != 0;
113 * Decrypt remainder of buffer.
117 MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
118 MD5Final(keybuf, &md5c);
119 des3_decrypt_pubkey(keybuf, buf + i, (len - i + 7) & ~7);
120 memset(keybuf, 0, sizeof(keybuf)); /* burn the evidence */
124 * We are now in the secret part of the key. The first four
125 * bytes should be of the form a, b, a, b.
129 if (buf[i] != buf[i + 2] || buf[i + 1] != buf[i + 3]) {
130 *error = "wrong passphrase";
137 * After that, we have one further bignum which is our
138 * decryption exponent, and then the three auxiliary values
141 i += makeprivate(buf + i, key);
144 i += ssh1_read_bignum(buf + i, &key->iqmp);
147 i += ssh1_read_bignum(buf + i, &key->q);
150 i += ssh1_read_bignum(buf + i, &key->p);
154 if (!rsa_verify(key)) {
155 *error = "rsa_verify failed";
162 memset(buf, 0, sizeof(buf)); /* burn the evidence */
166 int loadrsakey(const Filename *filename, struct RSAKey *key, char *passphrase,
167 const char **errorstr)
172 const char *error = NULL;
174 fp = f_open(*filename, "rb");
176 error = "can't open file";
181 * Read the first line of the file and see if it's a v1 private
184 if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) {
186 * This routine will take care of calling fclose() for us.
188 ret = loadrsakey_main(fp, key, FALSE, NULL, passphrase, &error);
193 * Otherwise, we have nothing. Return empty-handed.
195 error = "not an SSH-1 RSA file";
199 if ((ret != 1) && errorstr)
205 * See whether an RSA key is encrypted. Return its comment field as
208 int rsakey_encrypted(const Filename *filename, char **comment)
213 fp = f_open(*filename, "rb");
215 return 0; /* doesn't even exist */
218 * Read the first line of the file and see if it's a v1 private
221 if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) {
224 * This routine will take care of calling fclose() for us.
226 return loadrsakey_main(fp, NULL, FALSE, comment, NULL, &dummy);
229 return 0; /* wasn't the right kind of file */
233 * Return a malloc'ed chunk of memory containing the public blob of
234 * an RSA key, as given in the agent protocol (modulus bits,
235 * exponent, modulus).
237 int rsakey_pubblob(const Filename *filename, void **blob, int *bloblen,
238 const char **errorstr)
244 const char *error = NULL;
246 /* Default return if we fail. */
251 fp = f_open(*filename, "rb");
253 error = "can't open file";
258 * Read the first line of the file and see if it's a v1 private
261 if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) {
262 memset(&key, 0, sizeof(key));
263 if (loadrsakey_main(fp, &key, TRUE, NULL, NULL, &error)) {
264 *blob = rsa_public_blob(&key, bloblen);
269 error = "not an SSH-1 RSA file";
275 if ((ret != 1) && errorstr)
281 * Save an RSA key file. Return nonzero on success.
283 int saversakey(const Filename *filename, struct RSAKey *key, char *passphrase)
285 unsigned char buf[16384];
286 unsigned char keybuf[16];
287 struct MD5Context md5c;
288 unsigned char *p, *estart;
292 * Write the initial signature.
295 memcpy(p, rsa_signature, sizeof(rsa_signature));
296 p += sizeof(rsa_signature);
299 * One byte giving encryption type, and one reserved (zero)
302 *p++ = (passphrase ? SSH_CIPHER_3DES : 0);
307 * An ordinary SSH 1 public key consists of: a uint32
308 * containing the bit count, then two bignums containing the
309 * modulus and exponent respectively.
311 PUT_32BIT(p, bignum_bitcount(key->modulus));
313 p += ssh1_write_bignum(p, key->modulus);
314 p += ssh1_write_bignum(p, key->exponent);
317 * A string containing the comment field.
320 PUT_32BIT(p, strlen(key->comment));
322 memcpy(p, key->comment, strlen(key->comment));
323 p += strlen(key->comment);
330 * The encrypted portion starts here.
335 * Two bytes, then the same two bytes repeated.
337 *p++ = random_byte();
338 *p++ = random_byte();
344 * Four more bignums: the decryption exponent, then iqmp, then
347 p += ssh1_write_bignum(p, key->private_exponent);
348 p += ssh1_write_bignum(p, key->iqmp);
349 p += ssh1_write_bignum(p, key->q);
350 p += ssh1_write_bignum(p, key->p);
353 * Now write zeros until the encrypted portion is a multiple of
356 while ((p - estart) % 8)
360 * Now encrypt the encrypted portion.
364 MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
365 MD5Final(keybuf, &md5c);
366 des3_encrypt_pubkey(keybuf, estart, p - estart);
367 memset(keybuf, 0, sizeof(keybuf)); /* burn the evidence */
371 * Done. Write the result to the file.
373 fp = f_open(*filename, "wb");
375 int ret = (fwrite(buf, 1, p - buf, fp) == (size_t) (p - buf));
376 ret = ret && (fclose(fp) == 0);
382 /* ----------------------------------------------------------------------
383 * SSH2 private key load/store functions.
387 * PuTTY's own format for SSH2 keys is as follows:
389 * The file is text. Lines are terminated by CRLF, although CR-only
390 * and LF-only are tolerated on input.
392 * The first line says "PuTTY-User-Key-File-2: " plus the name of the
393 * algorithm ("ssh-dss", "ssh-rsa" etc).
395 * The next line says "Encryption: " plus an encryption type.
396 * Currently the only supported encryption types are "aes256-cbc"
399 * The next line says "Comment: " plus the comment string.
401 * Next there is a line saying "Public-Lines: " plus a number N.
402 * The following N lines contain a base64 encoding of the public
403 * part of the key. This is encoded as the standard SSH2 public key
404 * blob (with no initial length): so for RSA, for example, it will
411 * Next, there is a line saying "Private-Lines: " plus a number N,
412 * and then N lines containing the (potentially encrypted) private
413 * part of the key. For the key type "ssh-rsa", this will be
416 * mpint private_exponent
417 * mpint p (the larger of the two primes)
418 * mpint q (the smaller prime)
419 * mpint iqmp (the inverse of q modulo p)
420 * data padding (to reach a multiple of the cipher block size)
422 * And for "ssh-dss", it will be composed of
424 * mpint x (the private key parameter)
425 * [ string hash 20-byte hash of mpints p || q || g only in old format ]
427 * Finally, there is a line saying "Private-MAC: " plus a hex
428 * representation of a HMAC-SHA-1 of:
430 * string name of algorithm ("ssh-dss", "ssh-rsa")
431 * string encryption type
434 * string private-plaintext (the plaintext version of the
435 * private part, including the final
438 * The key to the MAC is itself a SHA-1 hash of:
440 * data "putty-private-key-file-mac-key"
443 * (An empty passphrase is used for unencrypted keys.)
445 * If the key is encrypted, the encryption key is derived from the
446 * passphrase by means of a succession of SHA-1 hashes. Each hash
449 * uint32 sequence-number
452 * where the sequence-number increases from zero. As many of these
453 * hashes are used as necessary.
455 * For backwards compatibility with snapshots between 0.51 and
456 * 0.52, we also support the older key file format, which begins
457 * with "PuTTY-User-Key-File-1" (version number differs). In this
458 * format the Private-MAC: field only covers the private-plaintext
459 * field and nothing else (and without the 4-byte string length on
460 * the front too). Moreover, for RSA keys the Private-MAC: field
461 * can be replaced with a Private-Hash: field which is a plain
462 * SHA-1 hash instead of an HMAC. This is not allowable in DSA
463 * keys. (Yes, the old format was a mess. Guess why it changed :-)
466 static int read_header(FILE * fp, char *header)
473 if (c == '\n' || c == '\r' || c == EOF)
474 return 0; /* failure */
480 return 1; /* success! */
483 return 0; /* failure */
487 return 0; /* failure */
490 static char *read_body(FILE * fp)
498 text = snewn(size, char);
504 if (c == '\r' || c == '\n') {
506 if (c != '\r' && c != '\n' && c != EOF)
514 if (len + 1 > size) {
516 text = sresize(text, size, char);
523 int base64_decode_atom(char *atom, unsigned char *out)
530 for (i = 0; i < 4; i++) {
532 if (c >= 'A' && c <= 'Z')
534 else if (c >= 'a' && c <= 'z')
536 else if (c >= '0' && c <= '9')
545 return 0; /* invalid atom */
549 if (vals[0] == -1 || vals[1] == -1)
551 if (vals[2] == -1 && vals[3] != -1)
556 else if (vals[2] != -1)
561 word = ((vals[0] << 18) |
562 (vals[1] << 12) | ((vals[2] & 0x3F) << 6) | (vals[3] & 0x3F));
563 out[0] = (word >> 16) & 0xFF;
565 out[1] = (word >> 8) & 0xFF;
567 out[2] = word & 0xFF;
571 static unsigned char *read_blob(FILE * fp, int nlines, int *bloblen)
578 /* We expect at most 64 base64 characters, ie 48 real bytes, per line. */
579 blob = snewn(48 * nlines, unsigned char);
581 for (i = 0; i < nlines; i++) {
582 line = read_body(fp);
587 linelen = strlen(line);
588 if (linelen % 4 != 0 || linelen > 64) {
593 for (j = 0; j < linelen; j += 4) {
594 k = base64_decode_atom(line + j, blob + len);
609 * Magic error return value for when the passphrase is wrong.
611 struct ssh2_userkey ssh2_wrong_passphrase = {
615 struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
616 char *passphrase, const char **errorstr)
619 char header[40], *b, *encryption, *comment, *mac;
620 const struct ssh_signkey *alg;
621 struct ssh2_userkey *ret;
622 int cipher, cipherblk;
623 unsigned char *public_blob, *private_blob;
624 int public_blob_len, private_blob_len;
625 int i, is_mac, old_fmt;
626 int passlen = passphrase ? strlen(passphrase) : 0;
627 const char *error = NULL;
629 ret = NULL; /* return NULL for most errors */
630 encryption = comment = mac = NULL;
631 public_blob = private_blob = NULL;
633 fp = f_open(*filename, "rb");
635 error = "can't open file";
639 /* Read the first header line which contains the key type. */
640 if (!read_header(fp, header))
642 if (0 == strcmp(header, "PuTTY-User-Key-File-2")) {
644 } else if (0 == strcmp(header, "PuTTY-User-Key-File-1")) {
645 /* this is an old key file; warn and then continue */
646 old_keyfile_warning();
649 error = "not a PuTTY SSH-2 private key";
652 error = "file format error";
653 if ((b = read_body(fp)) == NULL)
655 /* Select key algorithm structure. */
656 if (!strcmp(b, "ssh-rsa"))
658 else if (!strcmp(b, "ssh-dss"))
666 /* Read the Encryption header line. */
667 if (!read_header(fp, header) || 0 != strcmp(header, "Encryption"))
669 if ((encryption = read_body(fp)) == NULL)
671 if (!strcmp(encryption, "aes256-cbc")) {
674 } else if (!strcmp(encryption, "none")) {
682 /* Read the Comment header line. */
683 if (!read_header(fp, header) || 0 != strcmp(header, "Comment"))
685 if ((comment = read_body(fp)) == NULL)
688 /* Read the Public-Lines header line and the public blob. */
689 if (!read_header(fp, header) || 0 != strcmp(header, "Public-Lines"))
691 if ((b = read_body(fp)) == NULL)
695 if ((public_blob = read_blob(fp, i, &public_blob_len)) == NULL)
698 /* Read the Private-Lines header line and the Private blob. */
699 if (!read_header(fp, header) || 0 != strcmp(header, "Private-Lines"))
701 if ((b = read_body(fp)) == NULL)
705 if ((private_blob = read_blob(fp, i, &private_blob_len)) == NULL)
708 /* Read the Private-MAC or Private-Hash header line. */
709 if (!read_header(fp, header))
711 if (0 == strcmp(header, "Private-MAC")) {
712 if ((mac = read_body(fp)) == NULL)
715 } else if (0 == strcmp(header, "Private-Hash") &&
716 alg == &ssh_rsa && old_fmt) {
717 if ((mac = read_body(fp)) == NULL)
727 * Decrypt the private blob.
730 unsigned char key[40];
735 if (private_blob_len % cipherblk)
739 SHA_Bytes(&s, "\0\0\0\0", 4);
740 SHA_Bytes(&s, passphrase, passlen);
741 SHA_Final(&s, key + 0);
743 SHA_Bytes(&s, "\0\0\0\1", 4);
744 SHA_Bytes(&s, passphrase, passlen);
745 SHA_Final(&s, key + 20);
746 aes256_decrypt_pubkey(key, private_blob, private_blob_len);
754 unsigned char binary[20];
755 unsigned char *macdata;
760 /* MAC (or hash) only covers the private blob. */
761 macdata = private_blob;
762 maclen = private_blob_len;
766 int namelen = strlen(alg->name);
767 int enclen = strlen(encryption);
768 int commlen = strlen(comment);
769 maclen = (4 + namelen +
772 4 + public_blob_len +
773 4 + private_blob_len);
774 macdata = snewn(maclen, unsigned char);
776 #define DO_STR(s,len) PUT_32BIT(p,(len));memcpy(p+4,(s),(len));p+=4+(len)
777 DO_STR(alg->name, namelen);
778 DO_STR(encryption, enclen);
779 DO_STR(comment, commlen);
780 DO_STR(public_blob, public_blob_len);
781 DO_STR(private_blob, private_blob_len);
788 unsigned char mackey[20];
789 char header[] = "putty-private-key-file-mac-key";
792 SHA_Bytes(&s, header, sizeof(header)-1);
793 if (cipher && passphrase)
794 SHA_Bytes(&s, passphrase, passlen);
795 SHA_Final(&s, mackey);
797 hmac_sha1_simple(mackey, 20, macdata, maclen, binary);
799 memset(mackey, 0, sizeof(mackey));
800 memset(&s, 0, sizeof(s));
802 SHA_Simple(macdata, maclen, binary);
806 memset(macdata, 0, maclen);
810 for (i = 0; i < 20; i++)
811 sprintf(realmac + 2 * i, "%02x", binary[i]);
813 if (strcmp(mac, realmac)) {
814 /* An incorrect MAC is an unconditional Error if the key is
815 * unencrypted. Otherwise, it means Wrong Passphrase. */
817 ret = SSH2_WRONG_PASSPHRASE;
819 error = "MAC failed";
828 * Create and return the key.
830 ret = snew(struct ssh2_userkey);
832 ret->comment = comment;
833 ret->data = alg->createkey(public_blob, public_blob_len,
834 private_blob, private_blob_len);
839 error = "createkey failed";
870 char *ssh2_userkey_loadpub(const Filename *filename, char **algorithm,
871 int *pub_blob_len, const char **errorstr)
875 const struct ssh_signkey *alg;
876 unsigned char *public_blob;
879 const char *error = NULL;
883 fp = f_open(*filename, "rb");
885 error = "can't open file";
889 /* Read the first header line which contains the key type. */
890 if (!read_header(fp, header)
891 || (0 != strcmp(header, "PuTTY-User-Key-File-2") &&
892 0 != strcmp(header, "PuTTY-User-Key-File-1"))) {
893 error = "not a PuTTY SSH-2 private key";
896 error = "file format error";
897 if ((b = read_body(fp)) == NULL)
899 /* Select key algorithm structure. Currently only ssh-rsa. */
900 if (!strcmp(b, "ssh-rsa"))
902 else if (!strcmp(b, "ssh-dss"))
910 /* Read the Encryption header line. */
911 if (!read_header(fp, header) || 0 != strcmp(header, "Encryption"))
913 if ((b = read_body(fp)) == NULL)
915 sfree(b); /* we don't care */
917 /* Read the Comment header line. */
918 if (!read_header(fp, header) || 0 != strcmp(header, "Comment"))
920 if ((b = read_body(fp)) == NULL)
922 sfree(b); /* we don't care */
924 /* Read the Public-Lines header line and the public blob. */
925 if (!read_header(fp, header) || 0 != strcmp(header, "Public-Lines"))
927 if ((b = read_body(fp)) == NULL)
931 if ((public_blob = read_blob(fp, i, &public_blob_len)) == NULL)
936 *pub_blob_len = public_blob_len;
938 *algorithm = alg->name;
939 return (char *)public_blob;
954 int ssh2_userkey_encrypted(const Filename *filename, char **commentptr)
957 char header[40], *b, *comment;
963 fp = f_open(*filename, "rb");
966 if (!read_header(fp, header)
967 || (0 != strcmp(header, "PuTTY-User-Key-File-2") &&
968 0 != strcmp(header, "PuTTY-User-Key-File-1"))) {
972 if ((b = read_body(fp)) == NULL) {
976 sfree(b); /* we don't care about key type here */
977 /* Read the Encryption header line. */
978 if (!read_header(fp, header) || 0 != strcmp(header, "Encryption")) {
982 if ((b = read_body(fp)) == NULL) {
987 /* Read the Comment header line. */
988 if (!read_header(fp, header) || 0 != strcmp(header, "Comment")) {
993 if ((comment = read_body(fp)) == NULL) {
1000 *commentptr = comment;
1003 if (!strcmp(b, "aes256-cbc"))
1011 int base64_lines(int datalen)
1013 /* When encoding, we use 64 chars/line, which equals 48 real chars. */
1014 return (datalen + 47) / 48;
1017 void base64_encode(FILE * fp, unsigned char *data, int datalen, int cpl)
1023 while (datalen > 0) {
1024 n = (datalen < 3 ? datalen : 3);
1025 base64_encode_atom(data, n, out);
1028 for (i = 0; i < 4; i++) {
1029 if (linelen >= cpl) {
1040 int ssh2_save_userkey(const Filename *filename, struct ssh2_userkey *key,
1044 unsigned char *pub_blob, *priv_blob, *priv_blob_encrypted;
1045 int pub_blob_len, priv_blob_len, priv_encrypted_len;
1050 unsigned char priv_mac[20];
1053 * Fetch the key component blobs.
1055 pub_blob = key->alg->public_blob(key->data, &pub_blob_len);
1056 priv_blob = key->alg->private_blob(key->data, &priv_blob_len);
1057 if (!pub_blob || !priv_blob) {
1064 * Determine encryption details, and encrypt the private blob.
1067 cipherstr = "aes256-cbc";
1073 priv_encrypted_len = priv_blob_len + cipherblk - 1;
1074 priv_encrypted_len -= priv_encrypted_len % cipherblk;
1075 priv_blob_encrypted = snewn(priv_encrypted_len, unsigned char);
1076 memset(priv_blob_encrypted, 0, priv_encrypted_len);
1077 memcpy(priv_blob_encrypted, priv_blob, priv_blob_len);
1078 /* Create padding based on the SHA hash of the unpadded blob. This prevents
1079 * too easy a known-plaintext attack on the last block. */
1080 SHA_Simple(priv_blob, priv_blob_len, priv_mac);
1081 assert(priv_encrypted_len - priv_blob_len < 20);
1082 memcpy(priv_blob_encrypted + priv_blob_len, priv_mac,
1083 priv_encrypted_len - priv_blob_len);
1085 /* Now create the MAC. */
1087 unsigned char *macdata;
1090 int namelen = strlen(key->alg->name);
1091 int enclen = strlen(cipherstr);
1092 int commlen = strlen(key->comment);
1094 unsigned char mackey[20];
1095 char header[] = "putty-private-key-file-mac-key";
1097 maclen = (4 + namelen +
1101 4 + priv_encrypted_len);
1102 macdata = snewn(maclen, unsigned char);
1104 #define DO_STR(s,len) PUT_32BIT(p,(len));memcpy(p+4,(s),(len));p+=4+(len)
1105 DO_STR(key->alg->name, namelen);
1106 DO_STR(cipherstr, enclen);
1107 DO_STR(key->comment, commlen);
1108 DO_STR(pub_blob, pub_blob_len);
1109 DO_STR(priv_blob_encrypted, priv_encrypted_len);
1112 SHA_Bytes(&s, header, sizeof(header)-1);
1114 SHA_Bytes(&s, passphrase, strlen(passphrase));
1115 SHA_Final(&s, mackey);
1116 hmac_sha1_simple(mackey, 20, macdata, maclen, priv_mac);
1117 memset(macdata, 0, maclen);
1119 memset(mackey, 0, sizeof(mackey));
1120 memset(&s, 0, sizeof(s));
1124 unsigned char key[40];
1127 passlen = strlen(passphrase);
1130 SHA_Bytes(&s, "\0\0\0\0", 4);
1131 SHA_Bytes(&s, passphrase, passlen);
1132 SHA_Final(&s, key + 0);
1134 SHA_Bytes(&s, "\0\0\0\1", 4);
1135 SHA_Bytes(&s, passphrase, passlen);
1136 SHA_Final(&s, key + 20);
1137 aes256_encrypt_pubkey(key, priv_blob_encrypted,
1138 priv_encrypted_len);
1140 memset(key, 0, sizeof(key));
1141 memset(&s, 0, sizeof(s));
1144 fp = f_open(*filename, "w");
1147 fprintf(fp, "PuTTY-User-Key-File-2: %s\n", key->alg->name);
1148 fprintf(fp, "Encryption: %s\n", cipherstr);
1149 fprintf(fp, "Comment: %s\n", key->comment);
1150 fprintf(fp, "Public-Lines: %d\n", base64_lines(pub_blob_len));
1151 base64_encode(fp, pub_blob, pub_blob_len, 64);
1152 fprintf(fp, "Private-Lines: %d\n", base64_lines(priv_encrypted_len));
1153 base64_encode(fp, priv_blob_encrypted, priv_encrypted_len, 64);
1154 fprintf(fp, "Private-MAC: ");
1155 for (i = 0; i < 20; i++)
1156 fprintf(fp, "%02x", priv_mac[i]);
1161 memset(priv_blob, 0, priv_blob_len);
1163 sfree(priv_blob_encrypted);
1167 /* ----------------------------------------------------------------------
1168 * A function to determine the type of a private key file. Returns
1169 * 0 on failure, 1 or 2 on success.
1171 int key_type(const Filename *filename)
1175 const char putty2_sig[] = "PuTTY-User-Key-File-";
1176 const char sshcom_sig[] = "---- BEGIN SSH2 ENCRYPTED PRIVAT";
1177 const char openssh_sig[] = "-----BEGIN ";
1180 fp = f_open(*filename, "r");
1182 return SSH_KEYTYPE_UNOPENABLE;
1183 i = fread(buf, 1, sizeof(buf), fp);
1186 return SSH_KEYTYPE_UNOPENABLE;
1188 return SSH_KEYTYPE_UNKNOWN;
1189 if (!memcmp(buf, rsa_signature, sizeof(rsa_signature)-1))
1190 return SSH_KEYTYPE_SSH1;
1191 if (!memcmp(buf, putty2_sig, sizeof(putty2_sig)-1))
1192 return SSH_KEYTYPE_SSH2;
1193 if (!memcmp(buf, openssh_sig, sizeof(openssh_sig)-1))
1194 return SSH_KEYTYPE_OPENSSH;
1195 if (!memcmp(buf, sshcom_sig, sizeof(sshcom_sig)-1))
1196 return SSH_KEYTYPE_SSHCOM;
1197 return SSH_KEYTYPE_UNKNOWN; /* unrecognised or EOF */
1201 * Convert the type word to a string, for `wrong type' error
1204 char *key_type_to_str(int type)
1207 case SSH_KEYTYPE_UNOPENABLE: return "unable to open file"; break;
1208 case SSH_KEYTYPE_UNKNOWN: return "not a private key"; break;
1209 case SSH_KEYTYPE_SSH1: return "SSH1 private key"; break;
1210 case SSH_KEYTYPE_SSH2: return "PuTTY SSH2 private key"; break;
1211 case SSH_KEYTYPE_OPENSSH: return "OpenSSH SSH2 private key"; break;
1212 case SSH_KEYTYPE_SSHCOM: return "ssh.com SSH2 private key"; break;
1213 default: return "INTERNAL ERROR"; break;