#include <assert.h>
#include <ctype.h>
+#include "putty.h"
#include "ssh.h"
#include "misc.h"
-#define PUT_32BIT(cp, value) do { \
- (cp)[3] = (value); \
- (cp)[2] = (value) >> 8; \
- (cp)[1] = (value) >> 16; \
- (cp)[0] = (value) >> 24; } while (0)
+int openssh_encrypted(const Filename *filename);
+struct ssh2_userkey *openssh_read(const Filename *filename, char *passphrase,
+ const char **errmsg_p);
+int openssh_write(const Filename *filename, struct ssh2_userkey *key,
+ char *passphrase);
-#define GET_32BIT(cp) \
- (((unsigned long)(unsigned char)(cp)[0] << 24) | \
- ((unsigned long)(unsigned char)(cp)[1] << 16) | \
- ((unsigned long)(unsigned char)(cp)[2] << 8) | \
- ((unsigned long)(unsigned char)(cp)[3]))
-
-int openssh_encrypted(char *filename);
-struct ssh2_userkey *openssh_read(char *filename, char *passphrase);
+int sshcom_encrypted(const Filename *filename, char **comment);
+struct ssh2_userkey *sshcom_read(const Filename *filename, char *passphrase,
+ const char **errmsg_p);
+int sshcom_write(const Filename *filename, struct ssh2_userkey *key,
+ char *passphrase);
/*
* Given a key type, determine whether we know how to import it.
{
if (type == SSH_KEYTYPE_OPENSSH)
return 1;
+ if (type == SSH_KEYTYPE_SSHCOM)
+ return 1;
return 0;
}
int import_target_type(int type)
{
/*
- * There are no known foreign SSH1 key formats.
+ * There are no known foreign SSH-1 key formats.
*/
return SSH_KEYTYPE_SSH2;
}
/*
* Determine whether a foreign key is encrypted.
*/
-int import_encrypted(char *filename, int type, char **comment)
+int import_encrypted(const Filename *filename, int type, char **comment)
{
if (type == SSH_KEYTYPE_OPENSSH) {
- *comment = filename; /* OpenSSH doesn't do key comments */
+ /* OpenSSH doesn't do key comments */
+ *comment = dupstr(filename_to_str(filename));
return openssh_encrypted(filename);
}
+ if (type == SSH_KEYTYPE_SSHCOM) {
+ return sshcom_encrypted(filename, comment);
+ }
return 0;
}
/*
- * Import an SSH1 key.
+ * Import an SSH-1 key.
*/
-int import_ssh1(char *filename, int type, struct RSAKey *key, char *passphrase)
+int import_ssh1(const Filename *filename, int type,
+ struct RSAKey *key, char *passphrase, const char **errmsg_p)
{
return 0;
}
/*
- * Import an SSH2 key.
+ * Import an SSH-2 key.
*/
-struct ssh2_userkey *import_ssh2(char *filename, int type, char *passphrase)
+struct ssh2_userkey *import_ssh2(const Filename *filename, int type,
+ char *passphrase, const char **errmsg_p)
{
if (type == SSH_KEYTYPE_OPENSSH)
- return openssh_read(filename, passphrase);
+ return openssh_read(filename, passphrase, errmsg_p);
+ if (type == SSH_KEYTYPE_SSHCOM)
+ return sshcom_read(filename, passphrase, errmsg_p);
return NULL;
}
+/*
+ * Export an SSH-1 key.
+ */
+int export_ssh1(const Filename *filename, int type, struct RSAKey *key,
+ char *passphrase)
+{
+ return 0;
+}
+
+/*
+ * Export an SSH-2 key.
+ */
+int export_ssh2(const Filename *filename, int type,
+ struct ssh2_userkey *key, char *passphrase)
+{
+ if (type == SSH_KEYTYPE_OPENSSH)
+ return openssh_write(filename, key, passphrase);
+ if (type == SSH_KEYTYPE_SSHCOM)
+ return sshcom_write(filename, key, passphrase);
+ return 0;
+}
+
+/*
+ * Strip trailing CRs and LFs at the end of a line of text.
+ */
+void strip_crlf(char *str)
+{
+ char *p = str + strlen(str);
+
+ while (p > str && (p[-1] == '\r' || p[-1] == '\n'))
+ *--p = '\0';
+}
+
/* ----------------------------------------------------------------------
* Helper routines. (The base64 ones are defined in sshpubk.c.)
*/
(c) == '+' || (c) == '/' || (c) == '=' \
)
-extern int base64_decode_atom(char *atom, unsigned char *out);
-extern int base64_lines(int datalen);
-extern void base64_encode_atom(unsigned char *data, int n, char *out);
-extern void base64_encode(FILE * fp, unsigned char *data, int datalen);
-
/*
* Read an ASN.1/BER identifier and length pair.
*
/* Primitive versus constructed bit. */
#define ASN1_CONSTRUCTED (1 << 5)
-int ber_read_id_len(void *source, int sourcelen,
- int *id, int *length, int *flags)
+static int ber_read_id_len(void *source, int sourcelen,
+ int *id, int *length, int *flags)
{
unsigned char *p = (unsigned char *) source;
if ((*p & 0x1F) == 0x1F) {
*id = 0;
while (*p & 0x80) {
- *id = (*id << 7) | (*p & 0x7F);
p++, sourcelen--;
if (sourcelen == 0)
return -1;
+ *id = (*id << 7) | (*p & 0x7F);
}
- *id = (*id << 7) | (*p & 0x7F);
p++, sourcelen--;
} else {
*id = *p & 0x1F;
return p - (unsigned char *) source;
}
+/*
+ * Write an ASN.1/BER identifier and length pair. Returns the
+ * number of bytes consumed. Assumes dest contains enough space.
+ * Will avoid writing anything if dest is NULL, but still return
+ * amount of space required.
+ */
+static int ber_write_id_len(void *dest, int id, int length, int flags)
+{
+ unsigned char *d = (unsigned char *)dest;
+ int len = 0;
+
+ if (id <= 30) {
+ /*
+ * Identifier is one byte.
+ */
+ len++;
+ if (d) *d++ = id | flags;
+ } else {
+ int n;
+ /*
+ * Identifier is multiple bytes: the first byte is 11111
+ * plus the flags, and subsequent bytes encode the value of
+ * the identifier, 7 bits at a time, with the top bit of
+ * each byte 1 except the last one which is 0.
+ */
+ len++;
+ if (d) *d++ = 0x1F | flags;
+ for (n = 1; (id >> (7*n)) > 0; n++)
+ continue; /* count the bytes */
+ while (n--) {
+ len++;
+ if (d) *d++ = (n ? 0x80 : 0) | ((id >> (7*n)) & 0x7F);
+ }
+ }
+
+ if (length < 128) {
+ /*
+ * Length is one byte.
+ */
+ len++;
+ if (d) *d++ = length;
+ } else {
+ int n;
+ /*
+ * Length is multiple bytes. The first is 0x80 plus the
+ * number of subsequent bytes, and the subsequent bytes
+ * encode the actual length.
+ */
+ for (n = 1; (length >> (8*n)) > 0; n++)
+ continue; /* count the bytes */
+ len++;
+ if (d) *d++ = 0x80 | n;
+ while (n--) {
+ len++;
+ if (d) *d++ = (length >> (8*n)) & 0xFF;
+ }
+ }
+
+ return len;
+}
+
+static int put_string(void *target, void *data, int len)
+{
+ unsigned char *d = (unsigned char *)target;
+
+ PUT_32BIT(d, len);
+ memcpy(d+4, data, len);
+ return len+4;
+}
+
+static int put_mp(void *target, void *data, int len)
+{
+ unsigned char *d = (unsigned char *)target;
+ unsigned char *i = (unsigned char *)data;
+
+ if (*i & 0x80) {
+ PUT_32BIT(d, len+1);
+ d[4] = 0;
+ memcpy(d+5, data, len);
+ return len+5;
+ } else {
+ PUT_32BIT(d, len);
+ memcpy(d+4, data, len);
+ return len+4;
+ }
+}
+
+/* Simple structure to point to an mp-int within a blob. */
+struct mpint_pos { void *start; int bytes; };
+
+static int ssh2_read_mpint(void *data, int len, struct mpint_pos *ret)
+{
+ int bytes;
+ unsigned char *d = (unsigned char *) data;
+
+ if (len < 4)
+ goto error;
+ bytes = toint(GET_32BIT(d));
+ if (bytes < 0 || len-4 < bytes)
+ goto error;
+
+ ret->start = d + 4;
+ ret->bytes = bytes;
+ return bytes+4;
+
+ error:
+ ret->start = NULL;
+ ret->bytes = -1;
+ return len; /* ensure further calls fail as well */
+}
+
/* ----------------------------------------------------------------------
- * Code to read OpenSSH private keys.
+ * Code to read and write OpenSSH private keys.
*/
enum { OSSH_DSA, OSSH_RSA };
+enum { OSSH_ENC_3DES, OSSH_ENC_AES };
struct openssh_key {
int type;
- int encrypted;
+ int encrypted, encryption;
char iv[32];
unsigned char *keyblob;
int keyblob_len, keyblob_size;
};
-struct openssh_key *load_openssh_key(char *filename)
+static struct openssh_key *load_openssh_key(const Filename *filename,
+ const char **errmsg_p)
{
struct openssh_key *ret;
- FILE *fp;
- char buffer[256];
+ FILE *fp = NULL;
+ char *line = NULL;
char *errmsg, *p;
int headers_done;
+ char base64_bit[4];
+ int base64_chars = 0;
- ret = smalloc(sizeof(*ret));
+ ret = snew(struct openssh_key);
ret->keyblob = NULL;
ret->keyblob_len = ret->keyblob_size = 0;
ret->encrypted = 0;
memset(ret->iv, 0, sizeof(ret->iv));
- fp = fopen(filename, "r");
+ fp = f_open(filename, "r", FALSE);
if (!fp) {
- errmsg = "Unable to open key file";
+ errmsg = "unable to open key file";
goto error;
}
- if (!fgets(buffer, sizeof(buffer), fp) ||
- 0 != strncmp(buffer, "-----BEGIN ", 11) ||
- 0 != strcmp(buffer+strlen(buffer)-17, "PRIVATE KEY-----\n")) {
- errmsg = "File does not begin with OpenSSH key header";
+
+ if (!(line = fgetline(fp))) {
+ errmsg = "unexpected end of file";
goto error;
}
- if (!strcmp(buffer, "-----BEGIN RSA PRIVATE KEY-----\n"))
+ strip_crlf(line);
+ if (0 != strncmp(line, "-----BEGIN ", 11) ||
+ 0 != strcmp(line+strlen(line)-16, "PRIVATE KEY-----")) {
+ errmsg = "file does not begin with OpenSSH key header";
+ goto error;
+ }
+ if (!strcmp(line, "-----BEGIN RSA PRIVATE KEY-----"))
ret->type = OSSH_RSA;
- else if (!strcmp(buffer, "-----BEGIN DSA PRIVATE KEY-----\n"))
+ else if (!strcmp(line, "-----BEGIN DSA PRIVATE KEY-----"))
ret->type = OSSH_DSA;
else {
- errmsg = "Unrecognised key type";
+ errmsg = "unrecognised key type";
goto error;
}
+ smemclr(line, strlen(line));
+ sfree(line);
+ line = NULL;
headers_done = 0;
while (1) {
- if (!fgets(buffer, sizeof(buffer), fp)) {
- errmsg = "Unexpected end of file";
+ if (!(line = fgetline(fp))) {
+ errmsg = "unexpected end of file";
goto error;
}
- if (0 == strncmp(buffer, "-----END ", 9) &&
- 0 == strcmp(buffer+strlen(buffer)-17, "PRIVATE KEY-----\n"))
+ strip_crlf(line);
+ if (0 == strncmp(line, "-----END ", 9) &&
+ 0 == strcmp(line+strlen(line)-16, "PRIVATE KEY-----")) {
+ sfree(line);
+ line = NULL;
break; /* done */
- if ((p = strchr(buffer, ':')) != NULL) {
+ }
+ if ((p = strchr(line, ':')) != NULL) {
if (headers_done) {
- errmsg = "Header found in body of key data";
+ errmsg = "header found in body of key data";
goto error;
}
*p++ = '\0';
while (*p && isspace((unsigned char)*p)) p++;
- if (!strcmp(buffer, "Proc-Type")) {
+ if (!strcmp(line, "Proc-Type")) {
if (p[0] != '4' || p[1] != ',') {
errmsg = "Proc-Type is not 4 (only 4 is supported)";
goto error;
}
p += 2;
- if (!strcmp(p, "ENCRYPTED\n"))
+ if (!strcmp(p, "ENCRYPTED"))
ret->encrypted = 1;
- } else if (!strcmp(buffer, "DEK-Info")) {
- int i, j;
+ } else if (!strcmp(line, "DEK-Info")) {
+ int i, j, ivlen;
- if (strncmp(p, "DES-EDE3-CBC,", 13)) {
- errmsg = "Ciphers other than DES-EDE3-CBC not supported";
+ if (!strncmp(p, "DES-EDE3-CBC,", 13)) {
+ ret->encryption = OSSH_ENC_3DES;
+ ivlen = 8;
+ } else if (!strncmp(p, "AES-128-CBC,", 12)) {
+ ret->encryption = OSSH_ENC_AES;
+ ivlen = 16;
+ } else {
+ errmsg = "unsupported cipher";
goto error;
}
- p += 13;
- for (i = 0; i < 8; i++) {
- if (1 != sscanf(p, "%2x", &j))
- break;
+ p = strchr(p, ',') + 1;/* always non-NULL, by above checks */
+ for (i = 0; i < ivlen; i++) {
+ if (1 != sscanf(p, "%2x", &j)) {
+ errmsg = "expected more iv data in DEK-Info";
+ goto error;
+ }
ret->iv[i] = j;
p += 2;
}
- if (i < 8) {
- errmsg = "Expected 16-digit iv in DEK-Info";
+ if (*p) {
+ errmsg = "more iv data than expected in DEK-Info";
goto error;
}
}
} else {
headers_done = 1;
- p = buffer;
- while (isbase64(p[0]) && isbase64(p[1]) &&
- isbase64(p[2]) && isbase64(p[3])) {
- int len;
- unsigned char out[3];
+ p = line;
+ while (isbase64(*p)) {
+ base64_bit[base64_chars++] = *p;
+ if (base64_chars == 4) {
+ unsigned char out[3];
+ int len;
- len = base64_decode_atom(p, out);
+ base64_chars = 0;
- if (len <= 0) {
- errmsg = "Invalid base64 encoding";
- goto error;
- }
+ len = base64_decode_atom(base64_bit, out);
- if (ret->keyblob_len + len > ret->keyblob_size) {
- ret->keyblob_size = ret->keyblob_len + len + 256;
- ret->keyblob = srealloc(ret->keyblob, ret->keyblob_size);
- }
+ if (len <= 0) {
+ errmsg = "invalid base64 encoding";
+ goto error;
+ }
- memcpy(ret->keyblob + ret->keyblob_len, out, len);
- ret->keyblob_len += len;
+ if (ret->keyblob_len + len > ret->keyblob_size) {
+ ret->keyblob_size = ret->keyblob_len + len + 256;
+ ret->keyblob = sresize(ret->keyblob, ret->keyblob_size,
+ unsigned char);
+ }
- p += 4;
- }
+ memcpy(ret->keyblob + ret->keyblob_len, out, len);
+ ret->keyblob_len += len;
- if (isbase64(*p)) {
- errmsg = "base64 characters left at end of line";
- goto error;
+ smemclr(out, sizeof(out));
+ }
+
+ p++;
}
}
+ smemclr(line, strlen(line));
+ sfree(line);
+ line = NULL;
}
+ fclose(fp);
+ fp = NULL;
+
if (ret->keyblob_len == 0 || !ret->keyblob) {
- errmsg = "Key body not present";
+ errmsg = "key body not present";
goto error;
}
if (ret->encrypted && ret->keyblob_len % 8 != 0) {
- errmsg = "Encrypted key blob is not a multiple of cipher block size";
+ errmsg = "encrypted key blob is not a multiple of cipher block size";
goto error;
}
+ smemclr(base64_bit, sizeof(base64_bit));
+ if (errmsg_p) *errmsg_p = NULL;
return ret;
error:
+ if (line) {
+ smemclr(line, strlen(line));
+ sfree(line);
+ line = NULL;
+ }
+ smemclr(base64_bit, sizeof(base64_bit));
if (ret) {
- if (ret->keyblob) sfree(ret->keyblob);
+ if (ret->keyblob) {
+ smemclr(ret->keyblob, ret->keyblob_size);
+ sfree(ret->keyblob);
+ }
+ smemclr(ret, sizeof(*ret));
sfree(ret);
}
+ if (errmsg_p) *errmsg_p = errmsg;
+ if (fp) fclose(fp);
return NULL;
}
-int openssh_encrypted(char *filename)
+int openssh_encrypted(const Filename *filename)
{
- struct openssh_key *key = load_openssh_key(filename);
+ struct openssh_key *key = load_openssh_key(filename, NULL);
int ret;
if (!key)
return 0;
ret = key->encrypted;
+ smemclr(key->keyblob, key->keyblob_size);
sfree(key->keyblob);
+ smemclr(key, sizeof(*key));
sfree(key);
return ret;
}
-struct ssh2_userkey *openssh_read(char *filename, char *passphrase)
+struct ssh2_userkey *openssh_read(const Filename *filename, char *passphrase,
+ const char **errmsg_p)
{
- struct openssh_key *key = load_openssh_key(filename);
+ struct openssh_key *key = load_openssh_key(filename, errmsg_p);
struct ssh2_userkey *retkey;
unsigned char *p;
int ret, id, len, flags;
struct ssh2_userkey *retval = NULL;
char *errmsg;
unsigned char *blob;
- int blobptr, privptr;
- char *modptr;
- int modlen;
+ int blobsize = 0, blobptr, privptr;
+ char *modptr = NULL;
+ int modlen = 0;
+
+ blob = NULL;
if (!key)
return NULL;
* - let block B equal MD5(A || passphrase || iv)
* - block C would be MD5(B || passphrase || iv) and so on
* - encryption key is the first N bytes of A || B
+ *
+ * (Note that only 8 bytes of the iv are used for key
+ * derivation, even when the key is encrypted with AES and
+ * hence there are 16 bytes available.)
*/
struct MD5Context md5c;
unsigned char keybuf[32];
MD5Init(&md5c);
- MD5Update(&md5c, passphrase, strlen(passphrase));
- MD5Update(&md5c, key->iv, 8);
+ MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
+ MD5Update(&md5c, (unsigned char *)key->iv, 8);
MD5Final(keybuf, &md5c);
MD5Init(&md5c);
MD5Update(&md5c, keybuf, 16);
- MD5Update(&md5c, passphrase, strlen(passphrase));
- MD5Update(&md5c, key->iv, 8);
+ MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
+ MD5Update(&md5c, (unsigned char *)key->iv, 8);
MD5Final(keybuf+16, &md5c);
/*
* Now decrypt the key blob.
*/
- des3_decrypt_pubkey_ossh(keybuf, key->iv,
- key->keyblob, key->keyblob_len);
+ if (key->encryption == OSSH_ENC_3DES)
+ des3_decrypt_pubkey_ossh(keybuf, (unsigned char *)key->iv,
+ key->keyblob, key->keyblob_len);
+ else {
+ void *ctx;
+ assert(key->encryption == OSSH_ENC_AES);
+ ctx = aes_make_context();
+ aes128_key(ctx, keybuf);
+ aes_iv(ctx, (unsigned char *)key->iv);
+ aes_ssh2_decrypt_blk(ctx, key->keyblob, key->keyblob_len);
+ aes_free_context(ctx);
+ }
+
+ smemclr(&md5c, sizeof(md5c));
+ smemclr(keybuf, sizeof(keybuf));
}
/*
p = key->keyblob;
- /* Expect the SEQUENCE header. Take its absence as a failure to decrypt. */
+ /* Expect the SEQUENCE header. Take its absence as a failure to
+ * decrypt, if the key was encrypted. */
ret = ber_read_id_len(p, key->keyblob_len, &id, &len, &flags);
p += ret;
if (ret < 0 || id != 16) {
errmsg = "ASN.1 decoding failure";
- retval = SSH2_WRONG_PASSPHRASE;
+ retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
goto error;
}
num_integers = 9;
else if (key->type == OSSH_DSA)
num_integers = 6;
+ else
+ num_integers = 0; /* placate compiler warnings */
/*
* Space to create key blob in.
*/
- blob = smalloc(256+key->keyblob_len);
+ blobsize = 256+key->keyblob_len;
+ blob = snewn(blobsize, unsigned char);
PUT_32BIT(blob, 7);
if (key->type == OSSH_DSA)
memcpy(blob+4, "ssh-dss", 7);
if (ret < 0 || id != 2 ||
key->keyblob+key->keyblob_len-p < len) {
errmsg = "ASN.1 decoding failure";
+ retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
goto error;
}
* this is some sort of version indication).
*/
if (len != 1 || p[0] != 0) {
- errmsg = "Version number mismatch";
+ errmsg = "version number mismatch";
goto error;
}
} else if (key->type == OSSH_RSA) {
*/
if (i == 1) {
/* Save the details for after we deal with number 2. */
- modptr = p;
+ modptr = (char *)p;
modlen = len;
} else if (i != 6 && i != 7) {
PUT_32BIT(blob+blobptr, len);
* the sanity checks for free.
*/
assert(privptr > 0); /* should have bombed by now if not */
- retkey = smalloc(sizeof(struct ssh2_userkey));
+ retkey = snew(struct ssh2_userkey);
retkey->alg = (key->type == OSSH_RSA ? &ssh_rsa : &ssh_dss);
retkey->data = retkey->alg->createkey(blob, privptr,
blob+privptr, blobptr-privptr);
}
retkey->comment = dupstr("imported-openssh-key");
- if (blob) sfree(blob);
+ errmsg = NULL; /* no error */
+ retval = retkey;
+
+ error:
+ if (blob) {
+ smemclr(blob, blobsize);
+ sfree(blob);
+ }
+ smemclr(key->keyblob, key->keyblob_size);
sfree(key->keyblob);
+ smemclr(key, sizeof(*key));
sfree(key);
- return retkey;
+ if (errmsg_p) *errmsg_p = errmsg;
+ return retval;
+}
+
+int openssh_write(const Filename *filename, struct ssh2_userkey *key,
+ char *passphrase)
+{
+ unsigned char *pubblob, *privblob, *spareblob;
+ int publen, privlen, sparelen = 0;
+ unsigned char *outblob;
+ int outlen;
+ struct mpint_pos numbers[9];
+ int nnumbers, pos, len, seqlen, i;
+ char *header, *footer;
+ char zero[1];
+ unsigned char iv[8];
+ int ret = 0;
+ FILE *fp;
+
+ /*
+ * Fetch the key blobs.
+ */
+ pubblob = key->alg->public_blob(key->data, &publen);
+ privblob = key->alg->private_blob(key->data, &privlen);
+ spareblob = outblob = NULL;
+
+ /*
+ * Find the sequence of integers to be encoded into the OpenSSH
+ * key blob, and also decide on the header line.
+ */
+ if (key->alg == &ssh_rsa) {
+ int pos;
+ struct mpint_pos n, e, d, p, q, iqmp, dmp1, dmq1;
+ Bignum bd, bp, bq, bdmp1, bdmq1;
+
+ /*
+ * These blobs were generated from inside PuTTY, so we needn't
+ * treat them as untrusted.
+ */
+ pos = 4 + GET_32BIT(pubblob);
+ pos += ssh2_read_mpint(pubblob+pos, publen-pos, &e);
+ pos += ssh2_read_mpint(pubblob+pos, publen-pos, &n);
+ pos = 0;
+ pos += ssh2_read_mpint(privblob+pos, privlen-pos, &d);
+ pos += ssh2_read_mpint(privblob+pos, privlen-pos, &p);
+ pos += ssh2_read_mpint(privblob+pos, privlen-pos, &q);
+ pos += ssh2_read_mpint(privblob+pos, privlen-pos, &iqmp);
+
+ assert(e.start && iqmp.start); /* can't go wrong */
+
+ /* We also need d mod (p-1) and d mod (q-1). */
+ bd = bignum_from_bytes(d.start, d.bytes);
+ bp = bignum_from_bytes(p.start, p.bytes);
+ bq = bignum_from_bytes(q.start, q.bytes);
+ decbn(bp);
+ decbn(bq);
+ bdmp1 = bigmod(bd, bp);
+ bdmq1 = bigmod(bd, bq);
+ freebn(bd);
+ freebn(bp);
+ freebn(bq);
+
+ dmp1.bytes = (bignum_bitcount(bdmp1)+8)/8;
+ dmq1.bytes = (bignum_bitcount(bdmq1)+8)/8;
+ sparelen = dmp1.bytes + dmq1.bytes;
+ spareblob = snewn(sparelen, unsigned char);
+ dmp1.start = spareblob;
+ dmq1.start = spareblob + dmp1.bytes;
+ for (i = 0; i < dmp1.bytes; i++)
+ spareblob[i] = bignum_byte(bdmp1, dmp1.bytes-1 - i);
+ for (i = 0; i < dmq1.bytes; i++)
+ spareblob[i+dmp1.bytes] = bignum_byte(bdmq1, dmq1.bytes-1 - i);
+ freebn(bdmp1);
+ freebn(bdmq1);
+
+ numbers[0].start = zero; numbers[0].bytes = 1; zero[0] = '\0';
+ numbers[1] = n;
+ numbers[2] = e;
+ numbers[3] = d;
+ numbers[4] = p;
+ numbers[5] = q;
+ numbers[6] = dmp1;
+ numbers[7] = dmq1;
+ numbers[8] = iqmp;
+
+ nnumbers = 9;
+ header = "-----BEGIN RSA PRIVATE KEY-----\n";
+ footer = "-----END RSA PRIVATE KEY-----\n";
+ } else if (key->alg == &ssh_dss) {
+ int pos;
+ struct mpint_pos p, q, g, y, x;
+
+ /*
+ * These blobs were generated from inside PuTTY, so we needn't
+ * treat them as untrusted.
+ */
+ pos = 4 + GET_32BIT(pubblob);
+ pos += ssh2_read_mpint(pubblob+pos, publen-pos, &p);
+ pos += ssh2_read_mpint(pubblob+pos, publen-pos, &q);
+ pos += ssh2_read_mpint(pubblob+pos, publen-pos, &g);
+ pos += ssh2_read_mpint(pubblob+pos, publen-pos, &y);
+ pos = 0;
+ pos += ssh2_read_mpint(privblob+pos, privlen-pos, &x);
+
+ assert(y.start && x.start); /* can't go wrong */
+
+ numbers[0].start = zero; numbers[0].bytes = 1; zero[0] = '\0';
+ numbers[1] = p;
+ numbers[2] = q;
+ numbers[3] = g;
+ numbers[4] = y;
+ numbers[5] = x;
+
+ nnumbers = 6;
+ header = "-----BEGIN DSA PRIVATE KEY-----\n";
+ footer = "-----END DSA PRIVATE KEY-----\n";
+ } else {
+ assert(0); /* zoinks! */
+ exit(1); /* XXX: GCC doesn't understand assert() on some systems. */
+ }
+
+ /*
+ * Now count up the total size of the ASN.1 encoded integers,
+ * so as to determine the length of the containing SEQUENCE.
+ */
+ len = 0;
+ for (i = 0; i < nnumbers; i++) {
+ len += ber_write_id_len(NULL, 2, numbers[i].bytes, 0);
+ len += numbers[i].bytes;
+ }
+ seqlen = len;
+ /* Now add on the SEQUENCE header. */
+ len += ber_write_id_len(NULL, 16, seqlen, ASN1_CONSTRUCTED);
+ /* Round up to the cipher block size, ensuring we have at least one
+ * byte of padding (see below). */
+ outlen = len;
+ if (passphrase)
+ outlen = (outlen+8) &~ 7;
+
+ /*
+ * Now we know how big outblob needs to be. Allocate it.
+ */
+ outblob = snewn(outlen, unsigned char);
+
+ /*
+ * And write the data into it.
+ */
+ pos = 0;
+ pos += ber_write_id_len(outblob+pos, 16, seqlen, ASN1_CONSTRUCTED);
+ for (i = 0; i < nnumbers; i++) {
+ pos += ber_write_id_len(outblob+pos, 2, numbers[i].bytes, 0);
+ memcpy(outblob+pos, numbers[i].start, numbers[i].bytes);
+ pos += numbers[i].bytes;
+ }
+
+ /*
+ * Padding on OpenSSH keys is deterministic. The number of
+ * padding bytes is always more than zero, and always at most
+ * the cipher block length. The value of each padding byte is
+ * equal to the number of padding bytes. So a plaintext that's
+ * an exact multiple of the block size will be padded with 08
+ * 08 08 08 08 08 08 08 (assuming a 64-bit block cipher); a
+ * plaintext one byte less than a multiple of the block size
+ * will be padded with just 01.
+ *
+ * This enables the OpenSSL key decryption function to strip
+ * off the padding algorithmically and return the unpadded
+ * plaintext to the next layer: it looks at the final byte, and
+ * then expects to find that many bytes at the end of the data
+ * with the same value. Those are all removed and the rest is
+ * returned.
+ */
+ assert(pos == len);
+ while (pos < outlen) {
+ outblob[pos++] = outlen - len;
+ }
+
+ /*
+ * Encrypt the key.
+ *
+ * For the moment, we still encrypt our OpenSSH keys using
+ * old-style 3DES.
+ */
+ if (passphrase) {
+ /*
+ * Invent an iv. Then derive encryption key from passphrase
+ * and iv/salt:
+ *
+ * - let block A equal MD5(passphrase || iv)
+ * - let block B equal MD5(A || passphrase || iv)
+ * - block C would be MD5(B || passphrase || iv) and so on
+ * - encryption key is the first N bytes of A || B
+ */
+ struct MD5Context md5c;
+ unsigned char keybuf[32];
+
+ for (i = 0; i < 8; i++) iv[i] = random_byte();
+
+ MD5Init(&md5c);
+ MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
+ MD5Update(&md5c, iv, 8);
+ MD5Final(keybuf, &md5c);
+
+ MD5Init(&md5c);
+ MD5Update(&md5c, keybuf, 16);
+ MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
+ MD5Update(&md5c, iv, 8);
+ MD5Final(keybuf+16, &md5c);
+
+ /*
+ * Now encrypt the key blob.
+ */
+ des3_encrypt_pubkey_ossh(keybuf, iv, outblob, outlen);
+
+ smemclr(&md5c, sizeof(md5c));
+ smemclr(keybuf, sizeof(keybuf));
+ }
+
+ /*
+ * And save it. We'll use Unix line endings just in case it's
+ * subsequently transferred in binary mode.
+ */
+ fp = f_open(filename, "wb", TRUE); /* ensure Unix line endings */
+ if (!fp)
+ goto error;
+ fputs(header, fp);
+ if (passphrase) {
+ fprintf(fp, "Proc-Type: 4,ENCRYPTED\nDEK-Info: DES-EDE3-CBC,");
+ for (i = 0; i < 8; i++)
+ fprintf(fp, "%02X", iv[i]);
+ fprintf(fp, "\n\n");
+ }
+ base64_encode(fp, outblob, outlen, 64);
+ fputs(footer, fp);
+ fclose(fp);
+ ret = 1;
+
+ error:
+ if (outblob) {
+ smemclr(outblob, outlen);
+ sfree(outblob);
+ }
+ if (spareblob) {
+ smemclr(spareblob, sparelen);
+ sfree(spareblob);
+ }
+ if (privblob) {
+ smemclr(privblob, privlen);
+ sfree(privblob);
+ }
+ if (pubblob) {
+ smemclr(pubblob, publen);
+ sfree(pubblob);
+ }
+ return ret;
+}
+
+/* ----------------------------------------------------------------------
+ * Code to read ssh.com private keys.
+ */
+
+/*
+ * The format of the base64 blob is largely SSH-2-packet-formatted,
+ * except that mpints are a bit different: they're more like the
+ * old SSH-1 mpint. You have a 32-bit bit count N, followed by
+ * (N+7)/8 bytes of data.
+ *
+ * So. The blob contains:
+ *
+ * - uint32 0x3f6ff9eb (magic number)
+ * - uint32 size (total blob size)
+ * - string key-type (see below)
+ * - string cipher-type (tells you if key is encrypted)
+ * - string encrypted-blob
+ *
+ * (The first size field includes the size field itself and the
+ * magic number before it. All other size fields are ordinary SSH-2
+ * strings, so the size field indicates how much data is to
+ * _follow_.)
+ *
+ * The encrypted blob, once decrypted, contains a single string
+ * which in turn contains the payload. (This allows padding to be
+ * added after that string while still making it clear where the
+ * real payload ends. Also it probably makes for a reasonable
+ * decryption check.)
+ *
+ * The payload blob, for an RSA key, contains:
+ * - mpint e
+ * - mpint d
+ * - mpint n (yes, the public and private stuff is intermixed)
+ * - mpint u (presumably inverse of p mod q)
+ * - mpint p (p is the smaller prime)
+ * - mpint q (q is the larger)
+ *
+ * For a DSA key, the payload blob contains:
+ * - uint32 0
+ * - mpint p
+ * - mpint g
+ * - mpint q
+ * - mpint y
+ * - mpint x
+ *
+ * Alternatively, if the parameters are `predefined', that
+ * (0,p,g,q) sequence can be replaced by a uint32 1 and a string
+ * containing some predefined parameter specification. *shudder*,
+ * but I doubt we'll encounter this in real life.
+ *
+ * The key type strings are ghastly. The RSA key I looked at had a
+ * type string of
+ *
+ * `if-modn{sign{rsa-pkcs1-sha1},encrypt{rsa-pkcs1v2-oaep}}'
+ *
+ * and the DSA key wasn't much better:
+ *
+ * `dl-modp{sign{dsa-nist-sha1},dh{plain}}'
+ *
+ * It isn't clear that these will always be the same. I think it
+ * might be wise just to look at the `if-modn{sign{rsa' and
+ * `dl-modp{sign{dsa' prefixes.
+ *
+ * Finally, the encryption. The cipher-type string appears to be
+ * either `none' or `3des-cbc'. Looks as if this is SSH-2-style
+ * 3des-cbc (i.e. outer cbc rather than inner). The key is created
+ * from the passphrase by means of yet another hashing faff:
+ *
+ * - first 16 bytes are MD5(passphrase)
+ * - next 16 bytes are MD5(passphrase || first 16 bytes)
+ * - if there were more, they'd be MD5(passphrase || first 32),
+ * and so on.
+ */
+
+#define SSHCOM_MAGIC_NUMBER 0x3f6ff9eb
+
+struct sshcom_key {
+ char comment[256]; /* allowing any length is overkill */
+ unsigned char *keyblob;
+ int keyblob_len, keyblob_size;
+};
+
+static struct sshcom_key *load_sshcom_key(const Filename *filename,
+ const char **errmsg_p)
+{
+ struct sshcom_key *ret;
+ FILE *fp;
+ char *line = NULL;
+ int hdrstart, len;
+ char *errmsg, *p;
+ int headers_done;
+ char base64_bit[4];
+ int base64_chars = 0;
+
+ ret = snew(struct sshcom_key);
+ ret->comment[0] = '\0';
+ ret->keyblob = NULL;
+ ret->keyblob_len = ret->keyblob_size = 0;
+
+ fp = f_open(filename, "r", FALSE);
+ if (!fp) {
+ errmsg = "unable to open key file";
+ goto error;
+ }
+ if (!(line = fgetline(fp))) {
+ errmsg = "unexpected end of file";
+ goto error;
+ }
+ strip_crlf(line);
+ if (0 != strcmp(line, "---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----")) {
+ errmsg = "file does not begin with ssh.com key header";
+ goto error;
+ }
+ smemclr(line, strlen(line));
+ sfree(line);
+ line = NULL;
+
+ headers_done = 0;
+ while (1) {
+ if (!(line = fgetline(fp))) {
+ errmsg = "unexpected end of file";
+ goto error;
+ }
+ strip_crlf(line);
+ if (!strcmp(line, "---- END SSH2 ENCRYPTED PRIVATE KEY ----")) {
+ sfree(line);
+ line = NULL;
+ break; /* done */
+ }
+ if ((p = strchr(line, ':')) != NULL) {
+ if (headers_done) {
+ errmsg = "header found in body of key data";
+ goto error;
+ }
+ *p++ = '\0';
+ while (*p && isspace((unsigned char)*p)) p++;
+ hdrstart = p - line;
+
+ /*
+ * Header lines can end in a trailing backslash for
+ * continuation.
+ */
+ len = hdrstart + strlen(line+hdrstart);
+ assert(!line[len]);
+ while (line[len-1] == '\\') {
+ char *line2;
+ int line2len;
+
+ line2 = fgetline(fp);
+ if (!line2) {
+ errmsg = "unexpected end of file";
+ goto error;
+ }
+ strip_crlf(line2);
+
+ line2len = strlen(line2);
+ line = sresize(line, len + line2len + 1, char);
+ strcpy(line + len - 1, line2);
+ len += line2len - 1;
+ assert(!line[len]);
+
+ smemclr(line2, strlen(line2));
+ sfree(line2);
+ line2 = NULL;
+ }
+ p = line + hdrstart;
+ strip_crlf(p);
+ if (!strcmp(line, "Comment")) {
+ /* Strip quotes in comment if present. */
+ if (p[0] == '"' && p[strlen(p)-1] == '"') {
+ p++;
+ p[strlen(p)-1] = '\0';
+ }
+ strncpy(ret->comment, p, sizeof(ret->comment));
+ ret->comment[sizeof(ret->comment)-1] = '\0';
+ }
+ } else {
+ headers_done = 1;
+
+ p = line;
+ while (isbase64(*p)) {
+ base64_bit[base64_chars++] = *p;
+ if (base64_chars == 4) {
+ unsigned char out[3];
+
+ base64_chars = 0;
+
+ len = base64_decode_atom(base64_bit, out);
+
+ if (len <= 0) {
+ errmsg = "invalid base64 encoding";
+ goto error;
+ }
+
+ if (ret->keyblob_len + len > ret->keyblob_size) {
+ ret->keyblob_size = ret->keyblob_len + len + 256;
+ ret->keyblob = sresize(ret->keyblob, ret->keyblob_size,
+ unsigned char);
+ }
+
+ memcpy(ret->keyblob + ret->keyblob_len, out, len);
+ ret->keyblob_len += len;
+ }
+
+ p++;
+ }
+ }
+ smemclr(line, strlen(line));
+ sfree(line);
+ line = NULL;
+ }
+
+ if (ret->keyblob_len == 0 || !ret->keyblob) {
+ errmsg = "key body not present";
+ goto error;
+ }
+
+ fclose(fp);
+ if (errmsg_p) *errmsg_p = NULL;
+ return ret;
+
+ error:
+ if (fp)
+ fclose(fp);
+
+ if (line) {
+ smemclr(line, strlen(line));
+ sfree(line);
+ line = NULL;
+ }
+ if (ret) {
+ if (ret->keyblob) {
+ smemclr(ret->keyblob, ret->keyblob_size);
+ sfree(ret->keyblob);
+ }
+ smemclr(ret, sizeof(*ret));
+ sfree(ret);
+ }
+ if (errmsg_p) *errmsg_p = errmsg;
+ return NULL;
+}
+
+int sshcom_encrypted(const Filename *filename, char **comment)
+{
+ struct sshcom_key *key = load_sshcom_key(filename, NULL);
+ int pos, len, answer;
+
+ answer = 0;
+
+ *comment = NULL;
+ if (!key)
+ goto done;
+
+ /*
+ * Check magic number.
+ */
+ if (GET_32BIT(key->keyblob) != 0x3f6ff9eb) {
+ goto done; /* key is invalid */
+ }
+
+ /*
+ * Find the cipher-type string.
+ */
+ pos = 8;
+ if (key->keyblob_len < pos+4)
+ goto done; /* key is far too short */
+ len = toint(GET_32BIT(key->keyblob + pos));
+ if (len < 0 || len > key->keyblob_len - pos - 4)
+ goto done; /* key is far too short */
+ pos += 4 + len; /* skip key type */
+ len = toint(GET_32BIT(key->keyblob + pos)); /* find cipher-type length */
+ if (len < 0 || len > key->keyblob_len - pos - 4)
+ goto done; /* cipher type string is incomplete */
+ if (len != 4 || 0 != memcmp(key->keyblob + pos + 4, "none", 4))
+ answer = 1;
+
+ done:
+ if (key) {
+ *comment = dupstr(key->comment);
+ smemclr(key->keyblob, key->keyblob_size);
+ sfree(key->keyblob);
+ smemclr(key, sizeof(*key));
+ sfree(key);
+ } else {
+ *comment = dupstr("");
+ }
+ return answer;
+}
+
+static int sshcom_read_mpint(void *data, int len, struct mpint_pos *ret)
+{
+ unsigned bits, bytes;
+ unsigned char *d = (unsigned char *) data;
+
+ if (len < 4)
+ goto error;
+ bits = GET_32BIT(d);
+
+ bytes = (bits + 7) / 8;
+ if (len < 4+bytes)
+ goto error;
+
+ ret->start = d + 4;
+ ret->bytes = bytes;
+ return bytes+4;
error:
- if (blob) sfree(blob);
+ ret->start = NULL;
+ ret->bytes = -1;
+ return len; /* ensure further calls fail as well */
+}
+
+static int sshcom_put_mpint(void *target, void *data, int len)
+{
+ unsigned char *d = (unsigned char *)target;
+ unsigned char *i = (unsigned char *)data;
+ int bits = len * 8 - 1;
+
+ while (bits > 0) {
+ if (*i & (1 << (bits & 7)))
+ break;
+ if (!(bits-- & 7))
+ i++, len--;
+ }
+
+ PUT_32BIT(d, bits+1);
+ memcpy(d+4, i, len);
+ return len+4;
+}
+
+struct ssh2_userkey *sshcom_read(const Filename *filename, char *passphrase,
+ const char **errmsg_p)
+{
+ struct sshcom_key *key = load_sshcom_key(filename, errmsg_p);
+ char *errmsg;
+ int pos, len;
+ const char prefix_rsa[] = "if-modn{sign{rsa";
+ const char prefix_dsa[] = "dl-modp{sign{dsa";
+ enum { RSA, DSA } type;
+ int encrypted;
+ char *ciphertext;
+ int cipherlen;
+ struct ssh2_userkey *ret = NULL, *retkey;
+ const struct ssh_signkey *alg;
+ unsigned char *blob = NULL;
+ int blobsize = 0, publen, privlen;
+
+ if (!key)
+ return NULL;
+
+ /*
+ * Check magic number.
+ */
+ if (GET_32BIT(key->keyblob) != SSHCOM_MAGIC_NUMBER) {
+ errmsg = "key does not begin with magic number";
+ goto error;
+ }
+
+ /*
+ * Determine the key type.
+ */
+ pos = 8;
+ if (key->keyblob_len < pos+4 ||
+ (len = toint(GET_32BIT(key->keyblob + pos))) < 0 ||
+ len > key->keyblob_len - pos - 4) {
+ errmsg = "key blob does not contain a key type string";
+ goto error;
+ }
+ if (len > sizeof(prefix_rsa) - 1 &&
+ !memcmp(key->keyblob+pos+4, prefix_rsa, sizeof(prefix_rsa) - 1)) {
+ type = RSA;
+ } else if (len > sizeof(prefix_dsa) - 1 &&
+ !memcmp(key->keyblob+pos+4, prefix_dsa, sizeof(prefix_dsa) - 1)) {
+ type = DSA;
+ } else {
+ errmsg = "key is of unknown type";
+ goto error;
+ }
+ pos += 4+len;
+
+ /*
+ * Determine the cipher type.
+ */
+ if (key->keyblob_len < pos+4 ||
+ (len = toint(GET_32BIT(key->keyblob + pos))) < 0 ||
+ len > key->keyblob_len - pos - 4) {
+ errmsg = "key blob does not contain a cipher type string";
+ goto error;
+ }
+ if (len == 4 && !memcmp(key->keyblob+pos+4, "none", 4))
+ encrypted = 0;
+ else if (len == 8 && !memcmp(key->keyblob+pos+4, "3des-cbc", 8))
+ encrypted = 1;
+ else {
+ errmsg = "key encryption is of unknown type";
+ goto error;
+ }
+ pos += 4+len;
+
+ /*
+ * Get hold of the encrypted part of the key.
+ */
+ if (key->keyblob_len < pos+4 ||
+ (len = toint(GET_32BIT(key->keyblob + pos))) < 0 ||
+ len > key->keyblob_len - pos - 4) {
+ errmsg = "key blob does not contain actual key data";
+ goto error;
+ }
+ ciphertext = (char *)key->keyblob + pos + 4;
+ cipherlen = len;
+ if (cipherlen == 0) {
+ errmsg = "length of key data is zero";
+ goto error;
+ }
+
+ /*
+ * Decrypt it if necessary.
+ */
+ if (encrypted) {
+ /*
+ * Derive encryption key from passphrase and iv/salt:
+ *
+ * - let block A equal MD5(passphrase)
+ * - let block B equal MD5(passphrase || A)
+ * - block C would be MD5(passphrase || A || B) and so on
+ * - encryption key is the first N bytes of A || B
+ */
+ struct MD5Context md5c;
+ unsigned char keybuf[32], iv[8];
+
+ if (cipherlen % 8 != 0) {
+ errmsg = "encrypted part of key is not a multiple of cipher block"
+ " size";
+ goto error;
+ }
+
+ MD5Init(&md5c);
+ MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
+ MD5Final(keybuf, &md5c);
+
+ MD5Init(&md5c);
+ MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
+ MD5Update(&md5c, keybuf, 16);
+ MD5Final(keybuf+16, &md5c);
+
+ /*
+ * Now decrypt the key blob.
+ */
+ memset(iv, 0, sizeof(iv));
+ des3_decrypt_pubkey_ossh(keybuf, iv, (unsigned char *)ciphertext,
+ cipherlen);
+
+ smemclr(&md5c, sizeof(md5c));
+ smemclr(keybuf, sizeof(keybuf));
+
+ /*
+ * Hereafter we return WRONG_PASSPHRASE for any parsing
+ * error. (But only if we've just tried to decrypt it!
+ * Returning WRONG_PASSPHRASE for an unencrypted key is
+ * automatic doom.)
+ */
+ if (encrypted)
+ ret = SSH2_WRONG_PASSPHRASE;
+ }
+
+ /*
+ * Strip away the containing string to get to the real meat.
+ */
+ len = toint(GET_32BIT(ciphertext));
+ if (len < 0 || len > cipherlen-4) {
+ errmsg = "containing string was ill-formed";
+ goto error;
+ }
+ ciphertext += 4;
+ cipherlen = len;
+
+ /*
+ * Now we break down into RSA versus DSA. In either case we'll
+ * construct public and private blobs in our own format, and
+ * end up feeding them to alg->createkey().
+ */
+ blobsize = cipherlen + 256;
+ blob = snewn(blobsize, unsigned char);
+ privlen = 0;
+ if (type == RSA) {
+ struct mpint_pos n, e, d, u, p, q;
+ int pos = 0;
+ pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &e);
+ pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &d);
+ pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &n);
+ pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &u);
+ pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &p);
+ pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &q);
+ if (!q.start) {
+ errmsg = "key data did not contain six integers";
+ goto error;
+ }
+
+ alg = &ssh_rsa;
+ pos = 0;
+ pos += put_string(blob+pos, "ssh-rsa", 7);
+ pos += put_mp(blob+pos, e.start, e.bytes);
+ pos += put_mp(blob+pos, n.start, n.bytes);
+ publen = pos;
+ pos += put_string(blob+pos, d.start, d.bytes);
+ pos += put_mp(blob+pos, q.start, q.bytes);
+ pos += put_mp(blob+pos, p.start, p.bytes);
+ pos += put_mp(blob+pos, u.start, u.bytes);
+ privlen = pos - publen;
+ } else {
+ struct mpint_pos p, q, g, x, y;
+ int pos = 4;
+
+ assert(type == DSA); /* the only other option from the if above */
+
+ if (GET_32BIT(ciphertext) != 0) {
+ errmsg = "predefined DSA parameters not supported";
+ goto error;
+ }
+ pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &p);
+ pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &g);
+ pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &q);
+ pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &y);
+ pos += sshcom_read_mpint(ciphertext+pos, cipherlen-pos, &x);
+ if (!x.start) {
+ errmsg = "key data did not contain five integers";
+ goto error;
+ }
+
+ alg = &ssh_dss;
+ pos = 0;
+ pos += put_string(blob+pos, "ssh-dss", 7);
+ pos += put_mp(blob+pos, p.start, p.bytes);
+ pos += put_mp(blob+pos, q.start, q.bytes);
+ pos += put_mp(blob+pos, g.start, g.bytes);
+ pos += put_mp(blob+pos, y.start, y.bytes);
+ publen = pos;
+ pos += put_mp(blob+pos, x.start, x.bytes);
+ privlen = pos - publen;
+ }
+
+ assert(privlen > 0); /* should have bombed by now if not */
+
+ retkey = snew(struct ssh2_userkey);
+ retkey->alg = alg;
+ retkey->data = alg->createkey(blob, publen, blob+publen, privlen);
+ if (!retkey->data) {
+ sfree(retkey);
+ errmsg = "unable to create key data structure";
+ goto error;
+ }
+ retkey->comment = dupstr(key->comment);
+
+ errmsg = NULL; /* no error */
+ ret = retkey;
+
+ error:
+ if (blob) {
+ smemclr(blob, blobsize);
+ sfree(blob);
+ }
+ smemclr(key->keyblob, key->keyblob_size);
sfree(key->keyblob);
+ smemclr(key, sizeof(*key));
sfree(key);
- return retval;
+ if (errmsg_p) *errmsg_p = errmsg;
+ return ret;
+}
+
+int sshcom_write(const Filename *filename, struct ssh2_userkey *key,
+ char *passphrase)
+{
+ unsigned char *pubblob, *privblob;
+ int publen, privlen;
+ unsigned char *outblob;
+ int outlen;
+ struct mpint_pos numbers[6];
+ int nnumbers, initial_zero, pos, lenpos, i;
+ char *type;
+ char *ciphertext;
+ int cipherlen;
+ int ret = 0;
+ FILE *fp;
+
+ /*
+ * Fetch the key blobs.
+ */
+ pubblob = key->alg->public_blob(key->data, &publen);
+ privblob = key->alg->private_blob(key->data, &privlen);
+ outblob = NULL;
+
+ /*
+ * Find the sequence of integers to be encoded into the OpenSSH
+ * key blob, and also decide on the header line.
+ */
+ if (key->alg == &ssh_rsa) {
+ int pos;
+ struct mpint_pos n, e, d, p, q, iqmp;
+
+ /*
+ * These blobs were generated from inside PuTTY, so we needn't
+ * treat them as untrusted.
+ */
+ pos = 4 + GET_32BIT(pubblob);
+ pos += ssh2_read_mpint(pubblob+pos, publen-pos, &e);
+ pos += ssh2_read_mpint(pubblob+pos, publen-pos, &n);
+ pos = 0;
+ pos += ssh2_read_mpint(privblob+pos, privlen-pos, &d);
+ pos += ssh2_read_mpint(privblob+pos, privlen-pos, &p);
+ pos += ssh2_read_mpint(privblob+pos, privlen-pos, &q);
+ pos += ssh2_read_mpint(privblob+pos, privlen-pos, &iqmp);
+
+ assert(e.start && iqmp.start); /* can't go wrong */
+
+ numbers[0] = e;
+ numbers[1] = d;
+ numbers[2] = n;
+ numbers[3] = iqmp;
+ numbers[4] = q;
+ numbers[5] = p;
+
+ nnumbers = 6;
+ initial_zero = 0;
+ type = "if-modn{sign{rsa-pkcs1-sha1},encrypt{rsa-pkcs1v2-oaep}}";
+ } else if (key->alg == &ssh_dss) {
+ int pos;
+ struct mpint_pos p, q, g, y, x;
+
+ /*
+ * These blobs were generated from inside PuTTY, so we needn't
+ * treat them as untrusted.
+ */
+ pos = 4 + GET_32BIT(pubblob);
+ pos += ssh2_read_mpint(pubblob+pos, publen-pos, &p);
+ pos += ssh2_read_mpint(pubblob+pos, publen-pos, &q);
+ pos += ssh2_read_mpint(pubblob+pos, publen-pos, &g);
+ pos += ssh2_read_mpint(pubblob+pos, publen-pos, &y);
+ pos = 0;
+ pos += ssh2_read_mpint(privblob+pos, privlen-pos, &x);
+
+ assert(y.start && x.start); /* can't go wrong */
+
+ numbers[0] = p;
+ numbers[1] = g;
+ numbers[2] = q;
+ numbers[3] = y;
+ numbers[4] = x;
+
+ nnumbers = 5;
+ initial_zero = 1;
+ type = "dl-modp{sign{dsa-nist-sha1},dh{plain}}";
+ } else {
+ assert(0); /* zoinks! */
+ exit(1); /* XXX: GCC doesn't understand assert() on some systems. */
+ }
+
+ /*
+ * Total size of key blob will be somewhere under 512 plus
+ * combined length of integers. We'll calculate the more
+ * precise size as we construct the blob.
+ */
+ outlen = 512;
+ for (i = 0; i < nnumbers; i++)
+ outlen += 4 + numbers[i].bytes;
+ outblob = snewn(outlen, unsigned char);
+
+ /*
+ * Create the unencrypted key blob.
+ */
+ pos = 0;
+ PUT_32BIT(outblob+pos, SSHCOM_MAGIC_NUMBER); pos += 4;
+ pos += 4; /* length field, fill in later */
+ pos += put_string(outblob+pos, type, strlen(type));
+ {
+ char *ciphertype = passphrase ? "3des-cbc" : "none";
+ pos += put_string(outblob+pos, ciphertype, strlen(ciphertype));
+ }
+ lenpos = pos; /* remember this position */
+ pos += 4; /* encrypted-blob size */
+ pos += 4; /* encrypted-payload size */
+ if (initial_zero) {
+ PUT_32BIT(outblob+pos, 0);
+ pos += 4;
+ }
+ for (i = 0; i < nnumbers; i++)
+ pos += sshcom_put_mpint(outblob+pos,
+ numbers[i].start, numbers[i].bytes);
+ /* Now wrap up the encrypted payload. */
+ PUT_32BIT(outblob+lenpos+4, pos - (lenpos+8));
+ /* Pad encrypted blob to a multiple of cipher block size. */
+ if (passphrase) {
+ int padding = -(pos - (lenpos+4)) & 7;
+ while (padding--)
+ outblob[pos++] = random_byte();
+ }
+ ciphertext = (char *)outblob+lenpos+4;
+ cipherlen = pos - (lenpos+4);
+ assert(!passphrase || cipherlen % 8 == 0);
+ /* Wrap up the encrypted blob string. */
+ PUT_32BIT(outblob+lenpos, cipherlen);
+ /* And finally fill in the total length field. */
+ PUT_32BIT(outblob+4, pos);
+
+ assert(pos < outlen);
+
+ /*
+ * Encrypt the key.
+ */
+ if (passphrase) {
+ /*
+ * Derive encryption key from passphrase and iv/salt:
+ *
+ * - let block A equal MD5(passphrase)
+ * - let block B equal MD5(passphrase || A)
+ * - block C would be MD5(passphrase || A || B) and so on
+ * - encryption key is the first N bytes of A || B
+ */
+ struct MD5Context md5c;
+ unsigned char keybuf[32], iv[8];
+
+ MD5Init(&md5c);
+ MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
+ MD5Final(keybuf, &md5c);
+
+ MD5Init(&md5c);
+ MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase));
+ MD5Update(&md5c, keybuf, 16);
+ MD5Final(keybuf+16, &md5c);
+
+ /*
+ * Now decrypt the key blob.
+ */
+ memset(iv, 0, sizeof(iv));
+ des3_encrypt_pubkey_ossh(keybuf, iv, (unsigned char *)ciphertext,
+ cipherlen);
+
+ smemclr(&md5c, sizeof(md5c));
+ smemclr(keybuf, sizeof(keybuf));
+ }
+
+ /*
+ * And save it. We'll use Unix line endings just in case it's
+ * subsequently transferred in binary mode.
+ */
+ fp = f_open(filename, "wb", TRUE); /* ensure Unix line endings */
+ if (!fp)
+ goto error;
+ fputs("---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----\n", fp);
+ fprintf(fp, "Comment: \"");
+ /*
+ * Comment header is broken with backslash-newline if it goes
+ * over 70 chars. Although it's surrounded by quotes, it
+ * _doesn't_ escape backslashes or quotes within the string.
+ * Don't ask me, I didn't design it.
+ */
+ {
+ int slen = 60; /* starts at 60 due to "Comment: " */
+ char *c = key->comment;
+ while ((int)strlen(c) > slen) {
+ fprintf(fp, "%.*s\\\n", slen, c);
+ c += slen;
+ slen = 70; /* allow 70 chars on subsequent lines */
+ }
+ fprintf(fp, "%s\"\n", c);
+ }
+ base64_encode(fp, outblob, pos, 70);
+ fputs("---- END SSH2 ENCRYPTED PRIVATE KEY ----\n", fp);
+ fclose(fp);
+ ret = 1;
+
+ error:
+ if (outblob) {
+ smemclr(outblob, outlen);
+ sfree(outblob);
+ }
+ if (privblob) {
+ smemclr(privblob, privlen);
+ sfree(privblob);
+ }
+ if (pubblob) {
+ smemclr(pubblob, publen);
+ sfree(pubblob);
+ }
+ return ret;
}
projects / u / mdw / putty / blobdiff