#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_pem_encrypted(const Filename *filename);
+int openssh_new_encrypted(const Filename *filename);
+struct ssh2_userkey *openssh_pem_read(const Filename *filename,
+ char *passphrase,
+ const char **errmsg_p);
+struct ssh2_userkey *openssh_new_read(const Filename *filename,
+ char *passphrase,
+ const char **errmsg_p);
+int openssh_auto_write(const Filename *filename, struct ssh2_userkey *key,
+ char *passphrase);
+int openssh_pem_write(const Filename *filename, struct ssh2_userkey *key,
+ char *passphrase);
+int openssh_new_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.
*/
int import_possible(int type)
{
- if (type == SSH_KEYTYPE_OPENSSH)
+ if (type == SSH_KEYTYPE_OPENSSH_PEM)
+ return 1;
+ if (type == SSH_KEYTYPE_OPENSSH_NEW)
+ 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 */
- return openssh_encrypted(filename);
+ if (type == SSH_KEYTYPE_OPENSSH_PEM) {
+ /* OpenSSH PEM format doesn't contain a key comment at all */
+ *comment = dupstr(filename_to_str(filename));
+ return openssh_pem_encrypted(filename);
+ } else if (type == SSH_KEYTYPE_OPENSSH_NEW) {
+ /* OpenSSH new format does, but it's inside the encrypted
+ * section for some reason */
+ *comment = dupstr(filename_to_str(filename));
+ return openssh_new_encrypted(filename);
+ } else 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);
+ if (type == SSH_KEYTYPE_OPENSSH_PEM)
+ return openssh_pem_read(filename, passphrase, errmsg_p);
+ else if (type == SSH_KEYTYPE_OPENSSH_NEW)
+ return openssh_new_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_AUTO)
+ return openssh_auto_write(filename, key, passphrase);
+ if (type == SSH_KEYTYPE_OPENSSH_NEW)
+ return openssh_new_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 -1;
if (*p & 0x80) {
+ unsigned len;
int n = *p & 0x7F;
p++, sourcelen--;
if (sourcelen < n)
return -1;
- *length = 0;
+ len = 0;
while (n--)
- *length = (*length << 8) | (*p++);
+ len = (len << 8) | (*p++);
sourcelen -= n;
+ *length = toint(len);
} else {
*length = *p;
p++, sourcelen--;
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_uint32(void *target, unsigned val)
+{
+ unsigned char *d = (unsigned char *)target;
+
+ PUT_32BIT(d, val);
+ return 4;
+}
+
+static int put_string(void *target, const 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_string_z(void *target, const char *string)
+{
+ return put_string(target, string, strlen(string));
+}
+
+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, in the old-style PEM
+ * format.
*/
-enum { OSSH_DSA, OSSH_RSA };
-struct openssh_key {
- int type;
+typedef enum {
+ OP_DSA, OP_RSA, OP_ECDSA
+} openssh_pem_keytype;
+typedef enum {
+ OP_E_3DES, OP_E_AES
+} openssh_pem_enc;
+
+struct openssh_pem_key {
+ openssh_pem_keytype keytype;
int encrypted;
+ openssh_pem_enc encryption;
char iv[32];
unsigned char *keyblob;
int keyblob_len, keyblob_size;
};
-struct openssh_key *load_openssh_key(char *filename)
+static struct openssh_pem_key *load_openssh_pem_key(const Filename *filename,
+ const char **errmsg_p)
{
- struct openssh_key *ret;
- FILE *fp;
- char buffer[256];
- char *errmsg, *p;
+ struct openssh_pem_key *ret;
+ FILE *fp = NULL;
+ char *line = NULL;
+ const char *errmsg;
+ char *p;
int headers_done;
+ char base64_bit[4];
+ int base64_chars = 0;
- ret = smalloc(sizeof(*ret));
+ ret = snew(struct openssh_pem_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"))
- ret->type = OSSH_RSA;
- else if (!strcmp(buffer, "-----BEGIN DSA PRIVATE KEY-----\n"))
- ret->type = OSSH_DSA;
- else {
- errmsg = "Unrecognised key type";
+ strip_crlf(line);
+ if (!strstartswith(line, "-----BEGIN ") ||
+ !strendswith(line, "PRIVATE KEY-----")) {
+ errmsg = "file does not begin with OpenSSH key header";
+ goto error;
+ }
+ /*
+ * Parse the BEGIN line. For old-format keys, this tells us the
+ * type of the key; for new-format keys, all it tells us is the
+ * format, and we'll find out the key type once we parse the
+ * base64.
+ */
+ if (!strcmp(line, "-----BEGIN RSA PRIVATE KEY-----")) {
+ ret->keytype = OP_RSA;
+ } else if (!strcmp(line, "-----BEGIN DSA PRIVATE KEY-----")) {
+ ret->keytype = OP_DSA;
+ } else if (!strcmp(line, "-----BEGIN EC PRIVATE KEY-----")) {
+ ret->keytype = OP_ECDSA;
+ } else if (!strcmp(line, "-----BEGIN OPENSSH PRIVATE KEY-----")) {
+ errmsg = "this is a new-style OpenSSH key";
+ goto error;
+ } else {
+ errmsg = "unrecognised key type";
goto error;
}
+ smemclr(line, strlen(line));
+ sfree(line);
+ line = NULL;
+
+ ret->encrypted = FALSE;
+ memset(ret->iv, 0, sizeof(ret->iv));
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 (strstartswith(line, "-----END ") &&
+ strendswith(line, "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"))
- ret->encrypted = 1;
- } else if (!strcmp(buffer, "DEK-Info")) {
- int i, j;
+ if (!strcmp(p, "ENCRYPTED"))
+ ret->encrypted = TRUE;
+ } 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 = OP_E_3DES;
+ ivlen = 8;
+ } else if (!strncmp(p, "AES-128-CBC,", 12)) {
+ ret->encryption = OP_E_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";
- goto error;
+ 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_pem_encrypted(const Filename *filename)
{
- struct openssh_key *key = load_openssh_key(filename);
+ struct openssh_pem_key *key = load_openssh_pem_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_pem_read(const Filename *filename,
+ char *passphrase,
+ const char **errmsg_p)
{
- struct openssh_key *key = load_openssh_key(filename);
+ struct openssh_pem_key *key = load_openssh_pem_key(filename, errmsg_p);
struct ssh2_userkey *retkey;
- unsigned char *p;
+ unsigned char *p, *q;
int ret, id, len, flags;
int i, num_integers;
struct ssh2_userkey *retval = NULL;
- char *errmsg;
+ const 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;
if (key->encrypted) {
- /*
- * 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];
+ /*
+ * 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
+ *
+ * (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);
- MD5Final(keybuf, &md5c);
+ MD5Init(&md5c);
+ 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);
- MD5Final(keybuf+16, &md5c);
+ MD5Init(&md5c);
+ MD5Update(&md5c, keybuf, 16);
+ 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);
+ /*
+ * Now decrypt the key blob.
+ */
+ if (key->encryption == OP_E_3DES)
+ des3_decrypt_pubkey_ossh(keybuf, (unsigned char *)key->iv,
+ key->keyblob, key->keyblob_len);
+ else {
+ void *ctx;
+ assert(key->encryption == OP_E_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));
}
/*
*
* - For DSA, we expect them to be 0, p, q, g, y, x in that
* order.
+ *
+ * - In ECDSA the format is totally different: we see the
+ * SEQUENCE, but beneath is an INTEGER 1, OCTET STRING priv
+ * EXPLICIT [0] OID curve, EXPLICIT [1] BIT STRING pubPoint
*/
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;
- goto error;
+ if (ret < 0 || id != 16 || len < 0 ||
+ key->keyblob+key->keyblob_len-p < len) {
+ errmsg = "ASN.1 decoding failure";
+ retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
+ goto error;
}
/* Expect a load of INTEGERs. */
- if (key->type == OSSH_RSA)
- num_integers = 9;
- else if (key->type == OSSH_DSA)
- num_integers = 6;
-
- /*
- * Space to create key blob in.
- */
- blob = smalloc(256+key->keyblob_len);
- PUT_32BIT(blob, 7);
- if (key->type == OSSH_DSA)
- memcpy(blob+4, "ssh-dss", 7);
- else if (key->type == OSSH_RSA)
- memcpy(blob+4, "ssh-rsa", 7);
- blobptr = 4+7;
- privptr = -1;
-
- for (i = 0; i < num_integers; i++) {
- ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
- &id, &len, &flags);
- p += ret;
- if (ret < 0 || id != 2 ||
- key->keyblob+key->keyblob_len-p < len) {
- errmsg = "ASN.1 decoding failure";
- goto error;
- }
+ if (key->keytype == OP_RSA)
+ num_integers = 9;
+ else if (key->keytype == OP_DSA)
+ num_integers = 6;
+ else
+ num_integers = 0; /* placate compiler warnings */
- if (i == 0) {
- /*
- * The first integer should be zero always (I think
- * this is some sort of version indication).
- */
- if (len != 1 || p[0] != 0) {
- errmsg = "Version number mismatch";
- goto error;
- }
- } else if (key->type == OSSH_RSA) {
- /*
- * Integers 1 and 2 go into the public blob but in the
- * opposite order; integers 3, 4, 5 and 8 go into the
- * private blob. The other two (6 and 7) are ignored.
- */
- if (i == 1) {
- /* Save the details for after we deal with number 2. */
- modptr = p;
- modlen = len;
- } else if (i != 6 && i != 7) {
- PUT_32BIT(blob+blobptr, len);
- memcpy(blob+blobptr+4, p, len);
- blobptr += 4+len;
- if (i == 2) {
- PUT_32BIT(blob+blobptr, modlen);
- memcpy(blob+blobptr+4, modptr, modlen);
- blobptr += 4+modlen;
- privptr = blobptr;
- }
- }
- } else if (key->type == OSSH_DSA) {
- /*
- * Integers 1-4 go into the public blob; integer 5 goes
- * into the private blob.
- */
- PUT_32BIT(blob+blobptr, len);
- memcpy(blob+blobptr+4, p, len);
- blobptr += 4+len;
- if (i == 4)
- privptr = blobptr;
- }
- /* Skip past the number. */
- p += len;
- }
+ if (key->keytype == OP_ECDSA) {
+ /* And now for something completely different */
+ unsigned char *priv;
+ int privlen;
+ const struct ssh_signkey *alg;
+ const struct ec_curve *curve;
+ int algnamelen, curvenamelen;
+ /* Read INTEGER 1 */
+ ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
+ &id, &len, &flags);
+ p += ret;
+ if (ret < 0 || id != 2 || len != 1 ||
+ key->keyblob+key->keyblob_len-p < len || p[0] != 1) {
+ errmsg = "ASN.1 decoding failure";
+ retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
+ goto error;
+ }
+ p += 1;
+ /* Read private key OCTET STRING */
+ ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
+ &id, &len, &flags);
+ p += ret;
+ if (ret < 0 || id != 4 || len < 0 ||
+ key->keyblob+key->keyblob_len-p < len) {
+ errmsg = "ASN.1 decoding failure";
+ retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
+ goto error;
+ }
+ priv = p;
+ privlen = len;
+ p += len;
+ /* Read curve OID */
+ ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
+ &id, &len, &flags);
+ p += ret;
+ if (ret < 0 || id != 0 || len < 0 ||
+ key->keyblob+key->keyblob_len-p < len) {
+ errmsg = "ASN.1 decoding failure";
+ retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
+ goto error;
+ }
+ ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
+ &id, &len, &flags);
+ p += ret;
+ if (ret < 0 || id != 6 || len < 0 ||
+ key->keyblob+key->keyblob_len-p < len) {
+ errmsg = "ASN.1 decoding failure";
+ retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
+ goto error;
+ }
+ alg = ec_alg_by_oid(len, p, &curve);
+ if (!alg) {
+ errmsg = "Unsupported ECDSA curve.";
+ retval = NULL;
+ goto error;
+ }
+ p += len;
+ /* Read BIT STRING point */
+ ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
+ &id, &len, &flags);
+ p += ret;
+ if (ret < 0 || id != 1 || len < 0 ||
+ key->keyblob+key->keyblob_len-p < len) {
+ errmsg = "ASN.1 decoding failure";
+ retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
+ goto error;
+ }
+ ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
+ &id, &len, &flags);
+ p += ret;
+ if (ret < 0 || id != 3 || len < 0 ||
+ key->keyblob+key->keyblob_len-p < len ||
+ len != ((((curve->fieldBits + 7) / 8) * 2) + 2)) {
+ errmsg = "ASN.1 decoding failure";
+ retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
+ goto error;
+ }
+ p += 1; len -= 1; /* Skip 0x00 before point */
- /*
- * Now put together the actual key. Simplest way to do this is
- * to assemble our own key blobs and feed them to the createkey
- * functions; this is a bit faffy but it does mean we get all
- * the sanity checks for free.
- */
- assert(privptr > 0); /* should have bombed by now if not */
- retkey = smalloc(sizeof(struct ssh2_userkey));
- retkey->alg = (key->type == OSSH_RSA ? &ssh_rsa : &ssh_dss);
- retkey->data = retkey->alg->createkey(blob, privptr,
- blob+privptr, blobptr-privptr);
- if (!retkey->data) {
- sfree(retkey);
- errmsg = "unable to create key data structure";
+ /* Construct the key */
+ retkey = snew(struct ssh2_userkey);
+ if (!retkey) {
+ errmsg = "out of memory";
+ goto error;
+ }
+ retkey->alg = alg;
+ blob = snewn((4+19 + 4+8 + 4+len) + (4+1+privlen), unsigned char);
+ if (!blob) {
+ sfree(retkey);
+ errmsg = "out of memory";
+ goto error;
+ }
+
+ q = blob;
+
+ algnamelen = strlen(alg->name);
+ PUT_32BIT(q, algnamelen); q += 4;
+ memcpy(q, alg->name, algnamelen); q += algnamelen;
+
+ curvenamelen = strlen(curve->name);
+ PUT_32BIT(q, curvenamelen); q += 4;
+ memcpy(q, curve->name, curvenamelen); q += curvenamelen;
+
+ PUT_32BIT(q, len); q += 4;
+ memcpy(q, p, len); q += len;
+
+ /*
+ * To be acceptable to our createkey(), the private blob must
+ * contain a valid mpint, i.e. without the top bit set. But
+ * the input private string may have the top bit set, so we
+ * prefix a zero byte to ensure createkey() doesn't fail for
+ * that reason.
+ */
+ PUT_32BIT(q, privlen+1);
+ q[4] = 0;
+ memcpy(q+5, priv, privlen);
+
+ retkey->data = retkey->alg->createkey(retkey->alg,
+ blob, q-blob,
+ q, 5+privlen);
+
+ if (!retkey->data) {
+ sfree(retkey);
+ errmsg = "unable to create key data structure";
+ goto error;
+ }
+
+ } else if (key->keytype == OP_RSA || key->keytype == OP_DSA) {
+
+ /*
+ * Space to create key blob in.
+ */
+ blobsize = 256+key->keyblob_len;
+ blob = snewn(blobsize, unsigned char);
+ PUT_32BIT(blob, 7);
+ if (key->keytype == OP_DSA)
+ memcpy(blob+4, "ssh-dss", 7);
+ else if (key->keytype == OP_RSA)
+ memcpy(blob+4, "ssh-rsa", 7);
+ blobptr = 4+7;
+ privptr = -1;
+
+ for (i = 0; i < num_integers; i++) {
+ ret = ber_read_id_len(p, key->keyblob+key->keyblob_len-p,
+ &id, &len, &flags);
+ p += ret;
+ if (ret < 0 || id != 2 || len < 0 ||
+ key->keyblob+key->keyblob_len-p < len) {
+ errmsg = "ASN.1 decoding failure";
+ retval = key->encrypted ? SSH2_WRONG_PASSPHRASE : NULL;
+ goto error;
+ }
+
+ if (i == 0) {
+ /*
+ * The first integer should be zero always (I think
+ * this is some sort of version indication).
+ */
+ if (len != 1 || p[0] != 0) {
+ errmsg = "version number mismatch";
+ goto error;
+ }
+ } else if (key->keytype == OP_RSA) {
+ /*
+ * Integers 1 and 2 go into the public blob but in the
+ * opposite order; integers 3, 4, 5 and 8 go into the
+ * private blob. The other two (6 and 7) are ignored.
+ */
+ if (i == 1) {
+ /* Save the details for after we deal with number 2. */
+ modptr = (char *)p;
+ modlen = len;
+ } else if (i != 6 && i != 7) {
+ PUT_32BIT(blob+blobptr, len);
+ memcpy(blob+blobptr+4, p, len);
+ blobptr += 4+len;
+ if (i == 2) {
+ PUT_32BIT(blob+blobptr, modlen);
+ memcpy(blob+blobptr+4, modptr, modlen);
+ blobptr += 4+modlen;
+ privptr = blobptr;
+ }
+ }
+ } else if (key->keytype == OP_DSA) {
+ /*
+ * Integers 1-4 go into the public blob; integer 5 goes
+ * into the private blob.
+ */
+ PUT_32BIT(blob+blobptr, len);
+ memcpy(blob+blobptr+4, p, len);
+ blobptr += 4+len;
+ if (i == 4)
+ privptr = blobptr;
+ }
+
+ /* Skip past the number. */
+ p += len;
+ }
+
+ /*
+ * Now put together the actual key. Simplest way to do this is
+ * to assemble our own key blobs and feed them to the createkey
+ * functions; this is a bit faffy but it does mean we get all
+ * the sanity checks for free.
+ */
+ assert(privptr > 0); /* should have bombed by now if not */
+ retkey = snew(struct ssh2_userkey);
+ retkey->alg = (key->keytype == OP_RSA ? &ssh_rsa : &ssh_dss);
+ retkey->data = retkey->alg->createkey(retkey->alg, blob, privptr,
+ blob+privptr,
+ blobptr-privptr);
+ if (!retkey->data) {
+ sfree(retkey);
+ errmsg = "unable to create key data structure";
+ goto error;
+ }
+
+ } else {
+ assert(0 && "Bad key type from load_openssh_pem_key");
+ errmsg = "Bad key type from load_openssh_pem_key";
goto error;
}
+ /*
+ * The old key format doesn't include a comment in the private
+ * key file.
+ */
retkey->comment = dupstr("imported-openssh-key");
- if (blob) sfree(blob);
- sfree(key->keyblob);
- sfree(key);
- return retkey;
+
+ errmsg = NULL; /* no error */
+ retval = retkey;
error:
- if (blob) sfree(blob);
+ if (blob) {
+ smemclr(blob, blobsize);
+ sfree(blob);
+ }
+ smemclr(key->keyblob, key->keyblob_size);
sfree(key->keyblob);
+ smemclr(key, sizeof(*key));
sfree(key);
+ if (errmsg_p) *errmsg_p = errmsg;
return retval;
}
+
+int openssh_pem_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;
+ const 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;
+
+ outblob = NULL;
+ len = 0;
+
+ /*
+ * Encode the OpenSSH key blob, and also decide on the header
+ * line.
+ */
+ if (key->alg == &ssh_rsa || key->alg == &ssh_dss) {
+ /*
+ * The RSA and DSS handlers share some code because the two
+ * key types have very similar ASN.1 representations, as a
+ * plain SEQUENCE of big integers. So we set up a list of
+ * bignums per key type and then construct the actual blob in
+ * common code after that.
+ */
+ 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 { /* 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";
+ }
+
+ /*
+ * 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);
+
+ /*
+ * Now we know how big outblob needs to be. Allocate it.
+ */
+ outblob = snewn(len, 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;
+ }
+ } else if (key->alg == &ssh_ecdsa_nistp256 ||
+ key->alg == &ssh_ecdsa_nistp384 ||
+ key->alg == &ssh_ecdsa_nistp521) {
+ const unsigned char *oid;
+ int oidlen;
+ int pointlen;
+
+ /*
+ * Structure of asn1:
+ * SEQUENCE
+ * INTEGER 1
+ * OCTET STRING (private key)
+ * [0]
+ * OID (curve)
+ * [1]
+ * BIT STRING (0x00 public key point)
+ */
+ oid = ec_alg_oid(key->alg, &oidlen);
+ pointlen = (((struct ec_key *)key->data)->publicKey.curve->fieldBits
+ + 7) / 8 * 2;
+
+ len = ber_write_id_len(NULL, 2, 1, 0);
+ len += 1;
+ len += ber_write_id_len(NULL, 4, privlen - 4, 0);
+ len+= privlen - 4;
+ len += ber_write_id_len(NULL, 0, oidlen +
+ ber_write_id_len(NULL, 6, oidlen, 0),
+ ASN1_CLASS_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED);
+ len += ber_write_id_len(NULL, 6, oidlen, 0);
+ len += oidlen;
+ len += ber_write_id_len(NULL, 1, 2 + pointlen +
+ ber_write_id_len(NULL, 3, 2 + pointlen, 0),
+ ASN1_CLASS_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED);
+ len += ber_write_id_len(NULL, 3, 2 + pointlen, 0);
+ len += 2 + pointlen;
+
+ seqlen = len;
+ len += ber_write_id_len(NULL, 16, seqlen, ASN1_CONSTRUCTED);
+
+ outblob = snewn(len, unsigned char);
+ assert(outblob);
+
+ pos = 0;
+ pos += ber_write_id_len(outblob+pos, 16, seqlen, ASN1_CONSTRUCTED);
+ pos += ber_write_id_len(outblob+pos, 2, 1, 0);
+ outblob[pos++] = 1;
+ pos += ber_write_id_len(outblob+pos, 4, privlen - 4, 0);
+ memcpy(outblob+pos, privblob + 4, privlen - 4);
+ pos += privlen - 4;
+ pos += ber_write_id_len(outblob+pos, 0, oidlen +
+ ber_write_id_len(NULL, 6, oidlen, 0),
+ ASN1_CLASS_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED);
+ pos += ber_write_id_len(outblob+pos, 6, oidlen, 0);
+ memcpy(outblob+pos, oid, oidlen);
+ pos += oidlen;
+ pos += ber_write_id_len(outblob+pos, 1, 2 + pointlen +
+ ber_write_id_len(NULL, 3, 2 + pointlen, 0),
+ ASN1_CLASS_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED);
+ pos += ber_write_id_len(outblob+pos, 3, 2 + pointlen, 0);
+ outblob[pos++] = 0;
+ memcpy(outblob+pos, pubblob+39, 1 + pointlen);
+ pos += 1 + pointlen;
+
+ header = "-----BEGIN EC PRIVATE KEY-----\n";
+ footer = "-----END EC PRIVATE KEY-----\n";
+ } else {
+ assert(0); /* zoinks! */
+ exit(1); /* XXX: GCC doesn't understand assert() on some systems. */
+ }
+
+ /*
+ * Encrypt the key.
+ *
+ * For the moment, we still encrypt our OpenSSH keys using
+ * old-style 3DES.
+ */
+ if (passphrase) {
+ struct MD5Context md5c;
+ unsigned char keybuf[32];
+
+ /*
+ * Round up to the cipher block size, ensuring we have at
+ * least one byte of padding (see below).
+ */
+ outlen = (len+8) &~ 7;
+ {
+ unsigned char *tmp = snewn(outlen, unsigned char);
+ memcpy(tmp, outblob, len);
+ smemclr(outblob, len);
+ sfree(outblob);
+ outblob = tmp;
+ }
+
+ /*
+ * 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;
+ }
+
+ /*
+ * 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
+ */
+ 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));
+ } else {
+ /*
+ * If no encryption, the blob has exactly its original
+ * cleartext size.
+ */
+ outlen = len;
+ }
+
+ /*
+ * 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 and write OpenSSH private keys in the new-style format.
+ */
+
+typedef enum {
+ ON_E_NONE, ON_E_AES256CBC
+} openssh_new_cipher;
+typedef enum {
+ ON_K_NONE, ON_K_BCRYPT
+} openssh_new_kdf;
+
+struct openssh_new_key {
+ openssh_new_cipher cipher;
+ openssh_new_kdf kdf;
+ union {
+ struct {
+ int rounds;
+ /* This points to a position within keyblob, not a
+ * separately allocated thing */
+ const unsigned char *salt;
+ int saltlen;
+ } bcrypt;
+ } kdfopts;
+ int nkeys, key_wanted;
+ /* This too points to a position within keyblob */
+ unsigned char *privatestr;
+ int privatelen;
+
+ unsigned char *keyblob;
+ int keyblob_len, keyblob_size;
+};
+
+static struct openssh_new_key *load_openssh_new_key(const Filename *filename,
+ const char **errmsg_p)
+{
+ struct openssh_new_key *ret;
+ FILE *fp = NULL;
+ char *line = NULL;
+ const char *errmsg;
+ char *p;
+ char base64_bit[4];
+ int base64_chars = 0;
+ const void *filedata;
+ int filelen;
+ const void *string, *kdfopts, *bcryptsalt, *pubkey;
+ int stringlen, kdfoptlen, bcryptsaltlen, pubkeylen;
+ unsigned bcryptrounds, nkeys, key_index;
+
+ ret = snew(struct openssh_new_key);
+ 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 OPENSSH PRIVATE KEY-----")) {
+ errmsg = "file does not begin with OpenSSH new-style key header";
+ goto error;
+ }
+ smemclr(line, strlen(line));
+ sfree(line);
+ line = NULL;
+
+ while (1) {
+ if (!(line = fgetline(fp))) {
+ errmsg = "unexpected end of file";
+ goto error;
+ }
+ strip_crlf(line);
+ if (0 == strcmp(line, "-----END OPENSSH PRIVATE KEY-----")) {
+ sfree(line);
+ line = NULL;
+ break; /* done */
+ }
+
+ p = line;
+ while (isbase64(*p)) {
+ base64_bit[base64_chars++] = *p;
+ if (base64_chars == 4) {
+ unsigned char out[3];
+ int len;
+
+ 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;
+
+ 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";
+ goto error;
+ }
+
+ filedata = ret->keyblob;
+ filelen = ret->keyblob_len;
+
+ if (filelen < 15 || 0 != memcmp(filedata, "openssh-key-v1\0", 15)) {
+ errmsg = "new-style OpenSSH magic number missing\n";
+ goto error;
+ }
+ filedata = (const char *)filedata + 15;
+ filelen -= 15;
+
+ if (!(string = get_ssh_string(&filelen, &filedata, &stringlen))) {
+ errmsg = "encountered EOF before cipher name\n";
+ goto error;
+ }
+ if (match_ssh_id(stringlen, string, "none")) {
+ ret->cipher = ON_E_NONE;
+ } else if (match_ssh_id(stringlen, string, "aes256-cbc")) {
+ ret->cipher = ON_E_AES256CBC;
+ } else {
+ errmsg = "unrecognised cipher name\n";
+ goto error;
+ }
+
+ if (!(string = get_ssh_string(&filelen, &filedata, &stringlen))) {
+ errmsg = "encountered EOF before kdf name\n";
+ goto error;
+ }
+ if (match_ssh_id(stringlen, string, "none")) {
+ ret->kdf = ON_K_NONE;
+ } else if (match_ssh_id(stringlen, string, "bcrypt")) {
+ ret->kdf = ON_K_BCRYPT;
+ } else {
+ errmsg = "unrecognised kdf name\n";
+ goto error;
+ }
+
+ if (!(kdfopts = get_ssh_string(&filelen, &filedata, &kdfoptlen))) {
+ errmsg = "encountered EOF before kdf options\n";
+ goto error;
+ }
+ switch (ret->kdf) {
+ case ON_K_NONE:
+ if (kdfoptlen != 0) {
+ errmsg = "expected empty options string for 'none' kdf";
+ goto error;
+ }
+ break;
+ case ON_K_BCRYPT:
+ if (!(bcryptsalt = get_ssh_string(&kdfoptlen, &kdfopts,
+ &bcryptsaltlen))) {
+ errmsg = "bcrypt options string did not contain salt\n";
+ goto error;
+ }
+ if (!get_ssh_uint32(&kdfoptlen, &kdfopts, &bcryptrounds)) {
+ errmsg = "bcrypt options string did not contain round count\n";
+ goto error;
+ }
+ ret->kdfopts.bcrypt.salt = bcryptsalt;
+ ret->kdfopts.bcrypt.saltlen = bcryptsaltlen;
+ ret->kdfopts.bcrypt.rounds = bcryptrounds;
+ break;
+ }
+
+ /*
+ * At this point we expect a uint32 saying how many keys are
+ * stored in this file. OpenSSH new-style key files can
+ * contain more than one. Currently we don't have any user
+ * interface to specify which one we're trying to extract, so
+ * we just bomb out with an error if more than one is found in
+ * the file. However, I've put in all the mechanism here to
+ * extract the nth one for a given n, in case we later connect
+ * up some UI to that mechanism. Just arrange that the
+ * 'key_wanted' field is set to a value in the range [0,
+ * nkeys) by some mechanism.
+ */
+ if (!get_ssh_uint32(&filelen, &filedata, &nkeys)) {
+ errmsg = "encountered EOF before key count\n";
+ goto error;
+ }
+ if (nkeys != 1) {
+ errmsg = "multiple keys in new-style OpenSSH key file "
+ "not supported\n";
+ goto error;
+ }
+ ret->nkeys = nkeys;
+ ret->key_wanted = 0;
+
+ for (key_index = 0; key_index < nkeys; key_index++) {
+ if (!(pubkey = get_ssh_string(&filelen, &filedata, &pubkeylen))) {
+ errmsg = "encountered EOF before kdf options\n";
+ goto error;
+ }
+ }
+
+ /*
+ * Now we expect a string containing the encrypted part of the
+ * key file.
+ */
+ if (!(string = get_ssh_string(&filelen, &filedata, &stringlen))) {
+ errmsg = "encountered EOF before private key container\n";
+ goto error;
+ }
+ ret->privatestr = (unsigned char *)string;
+ ret->privatelen = stringlen;
+
+ /*
+ * And now we're done, until asked to actually decrypt.
+ */
+
+ 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) {
+ 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_new_encrypted(const Filename *filename)
+{
+ struct openssh_new_key *key = load_openssh_new_key(filename, NULL);
+ int ret;
+
+ if (!key)
+ return 0;
+ ret = (key->cipher != ON_E_NONE);
+ smemclr(key->keyblob, key->keyblob_size);
+ sfree(key->keyblob);
+ smemclr(key, sizeof(*key));
+ sfree(key);
+ return ret;
+}
+
+struct ssh2_userkey *openssh_new_read(const Filename *filename,
+ char *passphrase,
+ const char **errmsg_p)
+{
+ struct openssh_new_key *key = load_openssh_new_key(filename, errmsg_p);
+ struct ssh2_userkey *retkey = NULL;
+ int i;
+ struct ssh2_userkey *retval = NULL;
+ const char *errmsg;
+ unsigned checkint0, checkint1;
+ const void *priv, *string;
+ int privlen, stringlen, key_index;
+ const struct ssh_signkey *alg = NULL;
+
+ if (!key)
+ return NULL;
+
+ if (key->cipher != ON_E_NONE) {
+ unsigned char keybuf[48];
+ int keysize;
+
+ /*
+ * Construct the decryption key, and decrypt the string.
+ */
+ switch (key->cipher) {
+ case ON_E_NONE:
+ keysize = 0;
+ break;
+ case ON_E_AES256CBC:
+ keysize = 48; /* 32 byte key + 16 byte IV */
+ break;
+ default:
+ assert(0 && "Bad cipher enumeration value");
+ }
+ assert(keysize <= sizeof(keybuf));
+ switch (key->kdf) {
+ case ON_K_NONE:
+ memset(keybuf, 0, keysize);
+ break;
+ case ON_K_BCRYPT:
+ openssh_bcrypt(passphrase,
+ key->kdfopts.bcrypt.salt,
+ key->kdfopts.bcrypt.saltlen,
+ key->kdfopts.bcrypt.rounds,
+ keybuf, keysize);
+ break;
+ default:
+ assert(0 && "Bad kdf enumeration value");
+ }
+ switch (key->cipher) {
+ case ON_E_NONE:
+ break;
+ case ON_E_AES256CBC:
+ if (key->privatelen % 16 != 0) {
+ errmsg = "private key container length is not a"
+ " multiple of AES block size\n";
+ goto error;
+ }
+ {
+ void *ctx = aes_make_context();
+ aes256_key(ctx, keybuf);
+ aes_iv(ctx, keybuf + 32);
+ aes_ssh2_decrypt_blk(ctx, key->privatestr,
+ key->privatelen);
+ aes_free_context(ctx);
+ }
+ break;
+ default:
+ assert(0 && "Bad cipher enumeration value");
+ }
+ }
+
+ /*
+ * Now parse the entire encrypted section, and extract the key
+ * identified by key_wanted.
+ */
+ priv = key->privatestr;
+ privlen = key->privatelen;
+
+ if (!get_ssh_uint32(&privlen, &priv, &checkint0) ||
+ !get_ssh_uint32(&privlen, &priv, &checkint1) ||
+ checkint0 != checkint1) {
+ errmsg = "decryption check failed";
+ goto error;
+ }
+
+ retkey = NULL;
+ for (key_index = 0; key_index < key->nkeys; key_index++) {
+ const unsigned char *thiskey;
+ int thiskeylen;
+
+ /*
+ * Read the key type, which will tell us how to scan over
+ * the key to get to the next one.
+ */
+ if (!(string = get_ssh_string(&privlen, &priv, &stringlen))) {
+ errmsg = "expected key type in private string";
+ goto error;
+ }
+
+ /*
+ * Preliminary key type identification, and decide how
+ * many pieces of key we expect to see. Currently
+ * (conveniently) all key types can be seen as some number
+ * of strings, so we just need to know how many of them to
+ * skip over. (The numbers below exclude the key comment.)
+ */
+ {
+ /* find_pubkey_alg needs a zero-terminated copy of the
+ * algorithm name */
+ char *name_zt = dupprintf("%.*s", stringlen, (char *)string);
+ alg = find_pubkey_alg(name_zt);
+ sfree(name_zt);
+ }
+
+ if (!alg) {
+ errmsg = "private key type not recognised\n";
+ goto error;
+ }
+
+ thiskey = priv;
+
+ /*
+ * Skip over the pieces of key.
+ */
+ for (i = 0; i < alg->openssh_private_npieces; i++) {
+ if (!(string = get_ssh_string(&privlen, &priv, &stringlen))) {
+ errmsg = "ran out of data in mid-private-key";
+ goto error;
+ }
+ }
+
+ thiskeylen = (int)((const unsigned char *)priv -
+ (const unsigned char *)thiskey);
+ if (key_index == key->key_wanted) {
+ retkey = snew(struct ssh2_userkey);
+ retkey->comment = NULL;
+ retkey->alg = alg;
+ retkey->data = alg->openssh_createkey(alg, &thiskey, &thiskeylen);
+ if (!retkey->data) {
+ errmsg = "unable to create key data structure";
+ goto error;
+ }
+ }
+
+ /*
+ * Read the key comment.
+ */
+ if (!(string = get_ssh_string(&privlen, &priv, &stringlen))) {
+ errmsg = "ran out of data at key comment";
+ goto error;
+ }
+ if (key_index == key->key_wanted) {
+ assert(retkey);
+ retkey->comment = dupprintf("%.*s", stringlen,
+ (const char *)string);
+ }
+ }
+
+ if (!retkey) {
+ errmsg = "key index out of range";
+ goto error;
+ }
+
+ /*
+ * Now we expect nothing left but padding.
+ */
+ for (i = 0; i < privlen; i++) {
+ if (((const unsigned char *)priv)[i] != (unsigned char)(i+1)) {
+ errmsg = "padding at end of private string did not match";
+ goto error;
+ }
+ }
+
+ errmsg = NULL; /* no error */
+ retval = retkey;
+ retkey = NULL; /* prevent the free */
+
+ error:
+ if (retkey) {
+ sfree(retkey->comment);
+ if (retkey->data) {
+ assert(alg);
+ alg->freekey(retkey->data);
+ }
+ sfree(retkey);
+ }
+ smemclr(key->keyblob, key->keyblob_size);
+ sfree(key->keyblob);
+ smemclr(key, sizeof(*key));
+ sfree(key);
+ if (errmsg_p) *errmsg_p = errmsg;
+ return retval;
+}
+
+int openssh_new_write(const Filename *filename, struct ssh2_userkey *key,
+ char *passphrase)
+{
+ unsigned char *pubblob, *privblob, *outblob, *p;
+ unsigned char *private_section_start, *private_section_length_field;
+ int publen, privlen, commentlen, maxsize, padvalue, i;
+ unsigned checkint;
+ int ret = 0;
+ unsigned char bcrypt_salt[16];
+ const int bcrypt_rounds = 16;
+ FILE *fp;
+
+ /*
+ * Fetch the key blobs and find out the lengths of things.
+ */
+ pubblob = key->alg->public_blob(key->data, &publen);
+ i = key->alg->openssh_fmtkey(key->data, NULL, 0);
+ privblob = snewn(i, unsigned char);
+ privlen = key->alg->openssh_fmtkey(key->data, privblob, i);
+ assert(privlen == i);
+ commentlen = strlen(key->comment);
+
+ /*
+ * Allocate enough space for the full binary key format. No need
+ * to be absolutely precise here.
+ */
+ maxsize = (16 + /* magic number */
+ 32 + /* cipher name string */
+ 32 + /* kdf name string */
+ 64 + /* kdf options string */
+ 4 + /* key count */
+ 4+publen + /* public key string */
+ 4 + /* string header for private section */
+ 8 + /* checkint x 2 */
+ 4+strlen(key->alg->name) + /* key type string */
+ privlen + /* private blob */
+ 4+commentlen + /* comment string */
+ 16); /* padding at end of private section */
+ outblob = snewn(maxsize, unsigned char);
+
+ /*
+ * Construct the cleartext version of the blob.
+ */
+ p = outblob;
+
+ /* Magic number. */
+ memcpy(p, "openssh-key-v1\0", 15);
+ p += 15;
+
+ /* Cipher and kdf names, and kdf options. */
+ if (!passphrase) {
+ memset(bcrypt_salt, 0, sizeof(bcrypt_salt)); /* prevent warnings */
+ p += put_string_z(p, "none");
+ p += put_string_z(p, "none");
+ p += put_string_z(p, "");
+ } else {
+ unsigned char *q;
+ for (i = 0; i < (int)sizeof(bcrypt_salt); i++)
+ bcrypt_salt[i] = random_byte();
+ p += put_string_z(p, "aes256-cbc");
+ p += put_string_z(p, "bcrypt");
+ q = p;
+ p += 4;
+ p += put_string(p, bcrypt_salt, sizeof(bcrypt_salt));
+ p += put_uint32(p, bcrypt_rounds);
+ PUT_32BIT_MSB_FIRST(q, (unsigned)(p - (q+4)));
+ }
+
+ /* Number of keys. */
+ p += put_uint32(p, 1);
+
+ /* Public blob. */
+ p += put_string(p, pubblob, publen);
+
+ /* Begin private section. */
+ private_section_length_field = p;
+ p += 4;
+ private_section_start = p;
+
+ /* checkint. */
+ checkint = 0;
+ for (i = 0; i < 4; i++)
+ checkint = (checkint << 8) + random_byte();
+ p += put_uint32(p, checkint);
+ p += put_uint32(p, checkint);
+
+ /* Private key. The main private blob goes inline, with no string
+ * wrapper. */
+ p += put_string_z(p, key->alg->name);
+ memcpy(p, privblob, privlen);
+ p += privlen;
+
+ /* Comment. */
+ p += put_string_z(p, key->comment);
+
+ /* Pad out the encrypted section. */
+ padvalue = 1;
+ do {
+ *p++ = padvalue++;
+ } while ((p - private_section_start) & 15);
+
+ assert(p - outblob < maxsize);
+
+ /* Go back and fill in the length field for the private section. */
+ PUT_32BIT_MSB_FIRST(private_section_length_field,
+ p - private_section_start);
+
+ if (passphrase) {
+ /*
+ * Encrypt the private section. We need 48 bytes of key
+ * material: 32 bytes AES key + 16 bytes iv.
+ */
+ unsigned char keybuf[48];
+ void *ctx;
+
+ openssh_bcrypt(passphrase,
+ bcrypt_salt, sizeof(bcrypt_salt), bcrypt_rounds,
+ keybuf, sizeof(keybuf));
+
+ ctx = aes_make_context();
+ aes256_key(ctx, keybuf);
+ aes_iv(ctx, keybuf + 32);
+ aes_ssh2_encrypt_blk(ctx, private_section_start,
+ p - private_section_start);
+ aes_free_context(ctx);
+
+ 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 OPENSSH PRIVATE KEY-----\n", fp);
+ base64_encode(fp, outblob, p - outblob, 64);
+ fputs("-----END OPENSSH PRIVATE KEY-----\n", fp);
+ fclose(fp);
+ ret = 1;
+
+ error:
+ if (outblob) {
+ smemclr(outblob, maxsize);
+ sfree(outblob);
+ }
+ if (privblob) {
+ smemclr(privblob, privlen);
+ sfree(privblob);
+ }
+ if (pubblob) {
+ smemclr(pubblob, publen);
+ sfree(pubblob);
+ }
+ return ret;
+}
+
+/* ----------------------------------------------------------------------
+ * The switch function openssh_auto_write(), which chooses one of the
+ * concrete OpenSSH output formats based on the key type.
+ */
+int openssh_auto_write(const Filename *filename, struct ssh2_userkey *key,
+ char *passphrase)
+{
+ /*
+ * The old OpenSSH format supports a fixed list of key types. We
+ * assume that anything not in that fixed list is newer, and hence
+ * will use the new format.
+ */
+ if (key->alg == &ssh_dss ||
+ key->alg == &ssh_rsa ||
+ key->alg == &ssh_ecdsa_nistp256 ||
+ key->alg == &ssh_ecdsa_nistp384 ||
+ key->alg == &ssh_ecdsa_nistp521)
+ return openssh_pem_write(filename, key, passphrase);
+ else
+ return openssh_new_write(filename, key, passphrase);
+}
+
+/* ----------------------------------------------------------------------
+ * 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;
+ const char *errmsg;
+ char *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:
+ 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);
+ const 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(alg, 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);
+ 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;
+ const 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));
+ {
+ const 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 / PuTTY.git / blobdiff