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)) {
185 ret = loadrsakey_main(fp, key, FALSE, NULL, passphrase, &error);
190 * Otherwise, we have nothing. Return empty-handed.
193 error = "not an SSH-1 RSA file";
196 if ((ret != 1) && errorstr)
202 * See whether an RSA key is encrypted. Return its comment field as
205 int rsakey_encrypted(const Filename *filename, char **comment)
210 fp = f_open(*filename, "rb");
212 return 0; /* doesn't even exist */
215 * Read the first line of the file and see if it's a v1 private
218 if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) {
220 return loadrsakey_main(fp, NULL, FALSE, comment, NULL, &dummy);
223 return 0; /* wasn't the right kind of file */
227 * Return a malloc'ed chunk of memory containing the public blob of
228 * an RSA key, as given in the agent protocol (modulus bits,
229 * exponent, modulus).
231 int rsakey_pubblob(const Filename *filename, void **blob, int *bloblen,
232 const char **errorstr)
238 const char *error = NULL;
240 /* Default return if we fail. */
245 fp = f_open(*filename, "rb");
247 error = "can't open file";
252 * Read the first line of the file and see if it's a v1 private
255 if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) {
256 memset(&key, 0, sizeof(key));
257 if (loadrsakey_main(fp, &key, TRUE, NULL, NULL, &error)) {
258 *blob = rsa_public_blob(&key, bloblen);
263 error = "not an SSH-1 RSA file";
268 if ((ret != 1) && errorstr)
274 * Save an RSA key file. Return nonzero on success.
276 int saversakey(const Filename *filename, struct RSAKey *key, char *passphrase)
278 unsigned char buf[16384];
279 unsigned char keybuf[16];
280 struct MD5Context md5c;
281 unsigned char *p, *estart;
285 * Write the initial signature.
288 memcpy(p, rsa_signature, sizeof(rsa_signature));
289 p += sizeof(rsa_signature);
292 * One byte giving encryption type, and one reserved (zero)
295 *p++ = (passphrase ? SSH_CIPHER_3DES : 0);
300 * An ordinary SSH 1 public key consists of: a uint32
301 * containing the bit count, then two bignums containing the
302 * modulus and exponent respectively.
304 PUT_32BIT(p, bignum_bitcount(key->modulus));
306 p += ssh1_write_bignum(p, key->modulus);
307 p += ssh1_write_bignum(p, key->exponent);
310 * A string containing the comment field.
313 PUT_32BIT(p, strlen(key->comment));
315 memcpy(p, key->comment, strlen(key->comment));
316 p += strlen(key->comment);
323 * The encrypted portion starts here.
328 * Two bytes, then the same two bytes repeated.
330 *p++ = random_byte();
331 *p++ = random_byte();
337 * Four more bignums: the decryption exponent, then iqmp, then
340 p += ssh1_write_bignum(p, key->private_exponent);
341 p += ssh1_write_bignum(p, key->iqmp);
342 p += ssh1_write_bignum(p, key->q);
343 p += ssh1_write_bignum(p, key->p);
346 * Now write zeros until the encrypted portion is a multiple of
349 while ((p - estart) % 8)
353 * Now encrypt the encrypted portion.
357 MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
358 MD5Final(keybuf, &md5c);
359 des3_encrypt_pubkey(keybuf, estart, p - estart);
360 memset(keybuf, 0, sizeof(keybuf)); /* burn the evidence */
364 * Done. Write the result to the file.
366 fp = f_open(*filename, "wb");
368 int ret = (fwrite(buf, 1, p - buf, fp) == (size_t) (p - buf));
369 ret = ret && (fclose(fp) == 0);
375 /* ----------------------------------------------------------------------
376 * SSH2 private key load/store functions.
380 * PuTTY's own format for SSH2 keys is as follows:
382 * The file is text. Lines are terminated by CRLF, although CR-only
383 * and LF-only are tolerated on input.
385 * The first line says "PuTTY-User-Key-File-2: " plus the name of the
386 * algorithm ("ssh-dss", "ssh-rsa" etc).
388 * The next line says "Encryption: " plus an encryption type.
389 * Currently the only supported encryption types are "aes256-cbc"
392 * The next line says "Comment: " plus the comment string.
394 * Next there is a line saying "Public-Lines: " plus a number N.
395 * The following N lines contain a base64 encoding of the public
396 * part of the key. This is encoded as the standard SSH2 public key
397 * blob (with no initial length): so for RSA, for example, it will
404 * Next, there is a line saying "Private-Lines: " plus a number N,
405 * and then N lines containing the (potentially encrypted) private
406 * part of the key. For the key type "ssh-rsa", this will be
409 * mpint private_exponent
410 * mpint p (the larger of the two primes)
411 * mpint q (the smaller prime)
412 * mpint iqmp (the inverse of q modulo p)
413 * data padding (to reach a multiple of the cipher block size)
415 * And for "ssh-dss", it will be composed of
417 * mpint x (the private key parameter)
418 * [ string hash 20-byte hash of mpints p || q || g only in old format ]
420 * Finally, there is a line saying "Private-MAC: " plus a hex
421 * representation of a HMAC-SHA-1 of:
423 * string name of algorithm ("ssh-dss", "ssh-rsa")
424 * string encryption type
427 * string private-plaintext (the plaintext version of the
428 * private part, including the final
431 * The key to the MAC is itself a SHA-1 hash of:
433 * data "putty-private-key-file-mac-key"
436 * (An empty passphrase is used for unencrypted keys.)
438 * If the key is encrypted, the encryption key is derived from the
439 * passphrase by means of a succession of SHA-1 hashes. Each hash
442 * uint32 sequence-number
445 * where the sequence-number increases from zero. As many of these
446 * hashes are used as necessary.
448 * For backwards compatibility with snapshots between 0.51 and
449 * 0.52, we also support the older key file format, which begins
450 * with "PuTTY-User-Key-File-1" (version number differs). In this
451 * format the Private-MAC: field only covers the private-plaintext
452 * field and nothing else (and without the 4-byte string length on
453 * the front too). Moreover, for RSA keys the Private-MAC: field
454 * can be replaced with a Private-Hash: field which is a plain
455 * SHA-1 hash instead of an HMAC. This is not allowable in DSA
456 * keys. (Yes, the old format was a mess. Guess why it changed :-)
459 static int read_header(FILE * fp, char *header)
466 if (c == '\n' || c == '\r' || c == EOF)
467 return 0; /* failure */
473 return 1; /* success! */
476 return 0; /* failure */
480 return 0; /* failure */
483 static char *read_body(FILE * fp)
491 text = snewn(size, char);
497 if (c == '\r' || c == '\n') {
499 if (c != '\r' && c != '\n' && c != EOF)
507 if (len + 1 > size) {
509 text = sresize(text, size, char);
516 int base64_decode_atom(char *atom, unsigned char *out)
523 for (i = 0; i < 4; i++) {
525 if (c >= 'A' && c <= 'Z')
527 else if (c >= 'a' && c <= 'z')
529 else if (c >= '0' && c <= '9')
538 return 0; /* invalid atom */
542 if (vals[0] == -1 || vals[1] == -1)
544 if (vals[2] == -1 && vals[3] != -1)
549 else if (vals[2] != -1)
554 word = ((vals[0] << 18) |
555 (vals[1] << 12) | ((vals[2] & 0x3F) << 6) | (vals[3] & 0x3F));
556 out[0] = (word >> 16) & 0xFF;
558 out[1] = (word >> 8) & 0xFF;
560 out[2] = word & 0xFF;
564 static unsigned char *read_blob(FILE * fp, int nlines, int *bloblen)
571 /* We expect at most 64 base64 characters, ie 48 real bytes, per line. */
572 blob = snewn(48 * nlines, unsigned char);
574 for (i = 0; i < nlines; i++) {
575 line = read_body(fp);
580 linelen = strlen(line);
581 if (linelen % 4 != 0 || linelen > 64) {
586 for (j = 0; j < linelen; j += 4) {
587 k = base64_decode_atom(line + j, blob + len);
602 * Magic error return value for when the passphrase is wrong.
604 struct ssh2_userkey ssh2_wrong_passphrase = {
608 struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
609 char *passphrase, const char **errorstr)
612 char header[40], *b, *encryption, *comment, *mac;
613 const struct ssh_signkey *alg;
614 struct ssh2_userkey *ret;
615 int cipher, cipherblk;
616 unsigned char *public_blob, *private_blob;
617 int public_blob_len, private_blob_len;
618 int i, is_mac, old_fmt;
619 int passlen = passphrase ? strlen(passphrase) : 0;
620 const char *error = NULL;
622 ret = NULL; /* return NULL for most errors */
623 encryption = comment = mac = NULL;
624 public_blob = private_blob = NULL;
626 fp = f_open(*filename, "rb");
628 error = "can't open file";
632 /* Read the first header line which contains the key type. */
633 if (!read_header(fp, header))
635 if (0 == strcmp(header, "PuTTY-User-Key-File-2")) {
637 } else if (0 == strcmp(header, "PuTTY-User-Key-File-1")) {
638 /* this is an old key file; warn and then continue */
639 old_keyfile_warning();
642 error = "not a PuTTY SSH-2 private key";
645 error = "file format error";
646 if ((b = read_body(fp)) == NULL)
648 /* Select key algorithm structure. */
649 if (!strcmp(b, "ssh-rsa"))
651 else if (!strcmp(b, "ssh-dss"))
659 /* Read the Encryption header line. */
660 if (!read_header(fp, header) || 0 != strcmp(header, "Encryption"))
662 if ((encryption = read_body(fp)) == NULL)
664 if (!strcmp(encryption, "aes256-cbc")) {
667 } else if (!strcmp(encryption, "none")) {
675 /* Read the Comment header line. */
676 if (!read_header(fp, header) || 0 != strcmp(header, "Comment"))
678 if ((comment = read_body(fp)) == NULL)
681 /* Read the Public-Lines header line and the public blob. */
682 if (!read_header(fp, header) || 0 != strcmp(header, "Public-Lines"))
684 if ((b = read_body(fp)) == NULL)
688 if ((public_blob = read_blob(fp, i, &public_blob_len)) == NULL)
691 /* Read the Private-Lines header line and the Private blob. */
692 if (!read_header(fp, header) || 0 != strcmp(header, "Private-Lines"))
694 if ((b = read_body(fp)) == NULL)
698 if ((private_blob = read_blob(fp, i, &private_blob_len)) == NULL)
701 /* Read the Private-MAC or Private-Hash header line. */
702 if (!read_header(fp, header))
704 if (0 == strcmp(header, "Private-MAC")) {
705 if ((mac = read_body(fp)) == NULL)
708 } else if (0 == strcmp(header, "Private-Hash") &&
709 alg == &ssh_rsa && old_fmt) {
710 if ((mac = read_body(fp)) == NULL)
720 * Decrypt the private blob.
723 unsigned char key[40];
728 if (private_blob_len % cipherblk)
732 SHA_Bytes(&s, "\0\0\0\0", 4);
733 SHA_Bytes(&s, passphrase, passlen);
734 SHA_Final(&s, key + 0);
736 SHA_Bytes(&s, "\0\0\0\1", 4);
737 SHA_Bytes(&s, passphrase, passlen);
738 SHA_Final(&s, key + 20);
739 aes256_decrypt_pubkey(key, private_blob, private_blob_len);
747 unsigned char binary[20];
748 unsigned char *macdata;
753 /* MAC (or hash) only covers the private blob. */
754 macdata = private_blob;
755 maclen = private_blob_len;
759 int namelen = strlen(alg->name);
760 int enclen = strlen(encryption);
761 int commlen = strlen(comment);
762 maclen = (4 + namelen +
765 4 + public_blob_len +
766 4 + private_blob_len);
767 macdata = snewn(maclen, unsigned char);
769 #define DO_STR(s,len) PUT_32BIT(p,(len));memcpy(p+4,(s),(len));p+=4+(len)
770 DO_STR(alg->name, namelen);
771 DO_STR(encryption, enclen);
772 DO_STR(comment, commlen);
773 DO_STR(public_blob, public_blob_len);
774 DO_STR(private_blob, private_blob_len);
781 unsigned char mackey[20];
782 char header[] = "putty-private-key-file-mac-key";
785 SHA_Bytes(&s, header, sizeof(header)-1);
786 if (cipher && passphrase)
787 SHA_Bytes(&s, passphrase, passlen);
788 SHA_Final(&s, mackey);
790 hmac_sha1_simple(mackey, 20, macdata, maclen, binary);
792 memset(mackey, 0, sizeof(mackey));
793 memset(&s, 0, sizeof(s));
795 SHA_Simple(macdata, maclen, binary);
799 memset(macdata, 0, maclen);
803 for (i = 0; i < 20; i++)
804 sprintf(realmac + 2 * i, "%02x", binary[i]);
806 if (strcmp(mac, realmac)) {
807 /* An incorrect MAC is an unconditional Error if the key is
808 * unencrypted. Otherwise, it means Wrong Passphrase. */
810 ret = SSH2_WRONG_PASSPHRASE;
812 error = "MAC failed";
821 * Create and return the key.
823 ret = snew(struct ssh2_userkey);
825 ret->comment = comment;
826 ret->data = alg->createkey(public_blob, public_blob_len,
827 private_blob, private_blob_len);
832 error = "createkey failed";
863 char *ssh2_userkey_loadpub(const Filename *filename, char **algorithm,
864 int *pub_blob_len, const char **errorstr)
868 const struct ssh_signkey *alg;
869 unsigned char *public_blob;
872 const char *error = NULL;
876 fp = f_open(*filename, "rb");
878 error = "can't open file";
882 /* Read the first header line which contains the key type. */
883 if (!read_header(fp, header)
884 || (0 != strcmp(header, "PuTTY-User-Key-File-2") &&
885 0 != strcmp(header, "PuTTY-User-Key-File-1"))) {
886 error = "not a PuTTY SSH-2 private key";
889 error = "file format error";
890 if ((b = read_body(fp)) == NULL)
892 /* Select key algorithm structure. Currently only ssh-rsa. */
893 if (!strcmp(b, "ssh-rsa"))
895 else if (!strcmp(b, "ssh-dss"))
903 /* Read the Encryption header line. */
904 if (!read_header(fp, header) || 0 != strcmp(header, "Encryption"))
906 if ((b = read_body(fp)) == NULL)
908 sfree(b); /* we don't care */
910 /* Read the Comment header line. */
911 if (!read_header(fp, header) || 0 != strcmp(header, "Comment"))
913 if ((b = read_body(fp)) == NULL)
915 sfree(b); /* we don't care */
917 /* Read the Public-Lines header line and the public blob. */
918 if (!read_header(fp, header) || 0 != strcmp(header, "Public-Lines"))
920 if ((b = read_body(fp)) == NULL)
924 if ((public_blob = read_blob(fp, i, &public_blob_len)) == NULL)
929 *pub_blob_len = public_blob_len;
931 *algorithm = alg->name;
932 return (char *)public_blob;
947 int ssh2_userkey_encrypted(const Filename *filename, char **commentptr)
950 char header[40], *b, *comment;
956 fp = f_open(*filename, "rb");
959 if (!read_header(fp, header)
960 || (0 != strcmp(header, "PuTTY-User-Key-File-2") &&
961 0 != strcmp(header, "PuTTY-User-Key-File-1"))) {
965 if ((b = read_body(fp)) == NULL) {
969 sfree(b); /* we don't care about key type here */
970 /* Read the Encryption header line. */
971 if (!read_header(fp, header) || 0 != strcmp(header, "Encryption")) {
975 if ((b = read_body(fp)) == NULL) {
980 /* Read the Comment header line. */
981 if (!read_header(fp, header) || 0 != strcmp(header, "Comment")) {
986 if ((comment = read_body(fp)) == NULL) {
993 *commentptr = comment;
996 if (!strcmp(b, "aes256-cbc"))
1004 int base64_lines(int datalen)
1006 /* When encoding, we use 64 chars/line, which equals 48 real chars. */
1007 return (datalen + 47) / 48;
1010 void base64_encode(FILE * fp, unsigned char *data, int datalen, int cpl)
1016 while (datalen > 0) {
1017 n = (datalen < 3 ? datalen : 3);
1018 base64_encode_atom(data, n, out);
1021 for (i = 0; i < 4; i++) {
1022 if (linelen >= cpl) {
1033 int ssh2_save_userkey(const Filename *filename, struct ssh2_userkey *key,
1037 unsigned char *pub_blob, *priv_blob, *priv_blob_encrypted;
1038 int pub_blob_len, priv_blob_len, priv_encrypted_len;
1043 unsigned char priv_mac[20];
1046 * Fetch the key component blobs.
1048 pub_blob = key->alg->public_blob(key->data, &pub_blob_len);
1049 priv_blob = key->alg->private_blob(key->data, &priv_blob_len);
1050 if (!pub_blob || !priv_blob) {
1057 * Determine encryption details, and encrypt the private blob.
1060 cipherstr = "aes256-cbc";
1066 priv_encrypted_len = priv_blob_len + cipherblk - 1;
1067 priv_encrypted_len -= priv_encrypted_len % cipherblk;
1068 priv_blob_encrypted = snewn(priv_encrypted_len, unsigned char);
1069 memset(priv_blob_encrypted, 0, priv_encrypted_len);
1070 memcpy(priv_blob_encrypted, priv_blob, priv_blob_len);
1071 /* Create padding based on the SHA hash of the unpadded blob. This prevents
1072 * too easy a known-plaintext attack on the last block. */
1073 SHA_Simple(priv_blob, priv_blob_len, priv_mac);
1074 assert(priv_encrypted_len - priv_blob_len < 20);
1075 memcpy(priv_blob_encrypted + priv_blob_len, priv_mac,
1076 priv_encrypted_len - priv_blob_len);
1078 /* Now create the MAC. */
1080 unsigned char *macdata;
1083 int namelen = strlen(key->alg->name);
1084 int enclen = strlen(cipherstr);
1085 int commlen = strlen(key->comment);
1087 unsigned char mackey[20];
1088 char header[] = "putty-private-key-file-mac-key";
1090 maclen = (4 + namelen +
1094 4 + priv_encrypted_len);
1095 macdata = snewn(maclen, unsigned char);
1097 #define DO_STR(s,len) PUT_32BIT(p,(len));memcpy(p+4,(s),(len));p+=4+(len)
1098 DO_STR(key->alg->name, namelen);
1099 DO_STR(cipherstr, enclen);
1100 DO_STR(key->comment, commlen);
1101 DO_STR(pub_blob, pub_blob_len);
1102 DO_STR(priv_blob_encrypted, priv_encrypted_len);
1105 SHA_Bytes(&s, header, sizeof(header)-1);
1107 SHA_Bytes(&s, passphrase, strlen(passphrase));
1108 SHA_Final(&s, mackey);
1109 hmac_sha1_simple(mackey, 20, macdata, maclen, priv_mac);
1110 memset(macdata, 0, maclen);
1112 memset(mackey, 0, sizeof(mackey));
1113 memset(&s, 0, sizeof(s));
1117 unsigned char key[40];
1120 passlen = strlen(passphrase);
1123 SHA_Bytes(&s, "\0\0\0\0", 4);
1124 SHA_Bytes(&s, passphrase, passlen);
1125 SHA_Final(&s, key + 0);
1127 SHA_Bytes(&s, "\0\0\0\1", 4);
1128 SHA_Bytes(&s, passphrase, passlen);
1129 SHA_Final(&s, key + 20);
1130 aes256_encrypt_pubkey(key, priv_blob_encrypted,
1131 priv_encrypted_len);
1133 memset(key, 0, sizeof(key));
1134 memset(&s, 0, sizeof(s));
1137 fp = f_open(*filename, "w");
1140 fprintf(fp, "PuTTY-User-Key-File-2: %s\n", key->alg->name);
1141 fprintf(fp, "Encryption: %s\n", cipherstr);
1142 fprintf(fp, "Comment: %s\n", key->comment);
1143 fprintf(fp, "Public-Lines: %d\n", base64_lines(pub_blob_len));
1144 base64_encode(fp, pub_blob, pub_blob_len, 64);
1145 fprintf(fp, "Private-Lines: %d\n", base64_lines(priv_encrypted_len));
1146 base64_encode(fp, priv_blob_encrypted, priv_encrypted_len, 64);
1147 fprintf(fp, "Private-MAC: ");
1148 for (i = 0; i < 20; i++)
1149 fprintf(fp, "%02x", priv_mac[i]);
1154 memset(priv_blob, 0, priv_blob_len);
1156 sfree(priv_blob_encrypted);
1160 /* ----------------------------------------------------------------------
1161 * A function to determine the type of a private key file. Returns
1162 * 0 on failure, 1 or 2 on success.
1164 int key_type(const Filename *filename)
1168 const char putty2_sig[] = "PuTTY-User-Key-File-";
1169 const char sshcom_sig[] = "---- BEGIN SSH2 ENCRYPTED PRIVAT";
1170 const char openssh_sig[] = "-----BEGIN ";
1173 fp = f_open(*filename, "r");
1175 return SSH_KEYTYPE_UNOPENABLE;
1176 i = fread(buf, 1, sizeof(buf), fp);
1179 return SSH_KEYTYPE_UNOPENABLE;
1181 return SSH_KEYTYPE_UNKNOWN;
1182 if (!memcmp(buf, rsa_signature, sizeof(rsa_signature)-1))
1183 return SSH_KEYTYPE_SSH1;
1184 if (!memcmp(buf, putty2_sig, sizeof(putty2_sig)-1))
1185 return SSH_KEYTYPE_SSH2;
1186 if (!memcmp(buf, openssh_sig, sizeof(openssh_sig)-1))
1187 return SSH_KEYTYPE_OPENSSH;
1188 if (!memcmp(buf, sshcom_sig, sizeof(sshcom_sig)-1))
1189 return SSH_KEYTYPE_SSHCOM;
1190 return SSH_KEYTYPE_UNKNOWN; /* unrecognised or EOF */
1194 * Convert the type word to a string, for `wrong type' error
1197 char *key_type_to_str(int type)
1200 case SSH_KEYTYPE_UNOPENABLE: return "unable to open file"; break;
1201 case SSH_KEYTYPE_UNKNOWN: return "not a private key"; break;
1202 case SSH_KEYTYPE_SSH1: return "SSH1 private key"; break;
1203 case SSH_KEYTYPE_SSH2: return "PuTTY SSH2 private key"; break;
1204 case SSH_KEYTYPE_OPENSSH: return "OpenSSH SSH2 private key"; break;
1205 case SSH_KEYTYPE_SSHCOM: return "ssh.com SSH2 private key"; break;
1206 default: return "INTERNAL ERROR"; break;