X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/ee5c14220a9e2d3aeee34fa23db2e4ea1dcd32fb..71ed591e9e049cf1c64ec9ddc10e2158c2f76c89:/import.c diff --git a/import.c b/import.c index 930b6c58..d1ab7511 100644 --- a/import.c +++ b/import.c @@ -8,14 +8,15 @@ #include #include +#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) + (cp)[3] = (unsigned char)(value); \ + (cp)[2] = (unsigned char)((value) >> 8); \ + (cp)[1] = (unsigned char)((value) >> 16); \ + (cp)[0] = (unsigned char)((value) >> 24); } while (0) #define GET_32BIT(cp) \ (((unsigned long)(unsigned char)(cp)[0] << 24) | \ @@ -23,11 +24,15 @@ ((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 openssh_encrypted(const Filename *filename); +struct ssh2_userkey *openssh_read(const Filename *filename, char *passphrase); +int openssh_write(const Filename *filename, struct ssh2_userkey *key, + char *passphrase); -int sshcom_encrypted(char *filename, char **comment); -struct ssh2_userkey *sshcom_read(char *filename, char *passphrase); +int sshcom_encrypted(const Filename *filename, char **comment); +struct ssh2_userkey *sshcom_read(const Filename *filename, char *passphrase); +int sshcom_write(const Filename *filename, struct ssh2_userkey *key, + char *passphrase); /* * Given a key type, determine whether we know how to import it. @@ -57,10 +62,11 @@ int import_target_type(int type) /* * 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) { @@ -72,7 +78,8 @@ int import_encrypted(char *filename, int type, char **comment) /* * Import an SSH1 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) { return 0; } @@ -80,7 +87,8 @@ int import_ssh1(char *filename, int type, struct RSAKey *key, char *passphrase) /* * Import an SSH2 key. */ -struct ssh2_userkey *import_ssh2(char *filename, int type, char *passphrase) +struct ssh2_userkey *import_ssh2(const Filename *filename, int type, + char *passphrase) { if (type == SSH_KEYTYPE_OPENSSH) return openssh_read(filename, passphrase); @@ -89,6 +97,28 @@ struct ssh2_userkey *import_ssh2(char *filename, int type, char *passphrase) return NULL; } +/* + * Export an SSH1 key. + */ +int export_ssh1(const Filename *filename, int type, struct RSAKey *key, + char *passphrase) +{ + return 0; +} + +/* + * Export an SSH2 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; +} + /* ---------------------------------------------------------------------- * Helper routines. (The base64 ones are defined in sshpubk.c.) */ @@ -99,11 +129,6 @@ struct ssh2_userkey *import_ssh2(char *filename, int type, char *passphrase) (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. * @@ -123,8 +148,8 @@ extern void base64_encode(FILE * fp, unsigned char *data, int datalen); /* 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; @@ -135,12 +160,11 @@ int ber_read_id_len(void *source, int sourcelen, 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; @@ -167,6 +191,67 @@ int ber_read_id_len(void *source, int 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_string(void *target, void *data, int len) { unsigned char *d = (unsigned char *)target; @@ -193,8 +278,32 @@ static int put_mp(void *target, void *data, int len) } } +/* 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 = GET_32BIT(d); + 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 */ +} + /* ---------------------------------------------------------------------- - * Code to read OpenSSH private keys. + * Code to read and write OpenSSH private keys. */ enum { OSSH_DSA, OSSH_RSA }; @@ -206,7 +315,7 @@ struct openssh_key { int keyblob_len, keyblob_size; }; -struct openssh_key *load_openssh_key(char *filename) +static struct openssh_key *load_openssh_key(const Filename *filename) { struct openssh_key *ret; FILE *fp; @@ -216,13 +325,13 @@ struct openssh_key *load_openssh_key(char *filename) 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"); if (!fp) { errmsg = "Unable to open key file"; goto error; @@ -306,7 +415,8 @@ struct openssh_key *load_openssh_key(char *filename) if (ret->keyblob_len + len > ret->keyblob_size) { ret->keyblob_size = ret->keyblob_len + len + 256; - ret->keyblob = srealloc(ret->keyblob, ret->keyblob_size); + ret->keyblob = sresize(ret->keyblob, ret->keyblob_size, + unsigned char); } memcpy(ret->keyblob + ret->keyblob_len, out, len); @@ -348,7 +458,7 @@ struct openssh_key *load_openssh_key(char *filename) return NULL; } -int openssh_encrypted(char *filename) +int openssh_encrypted(const Filename *filename) { struct openssh_key *key = load_openssh_key(filename); int ret; @@ -363,7 +473,7 @@ int openssh_encrypted(char *filename) return ret; } -struct ssh2_userkey *openssh_read(char *filename, char *passphrase) +struct ssh2_userkey *openssh_read(const Filename *filename, char *passphrase) { struct openssh_key *key = load_openssh_key(filename); struct ssh2_userkey *retkey; @@ -373,9 +483,11 @@ struct ssh2_userkey *openssh_read(char *filename, char *passphrase) struct ssh2_userkey *retval = NULL; char *errmsg; unsigned char *blob; - int blobsize, blobptr, privptr; - char *modptr; - int modlen; + int blobsize = 0, blobptr, privptr; + char *modptr = NULL; + int modlen = 0; + + blob = NULL; if (!key) return NULL; @@ -393,20 +505,20 @@ struct ssh2_userkey *openssh_read(char *filename, char *passphrase) 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, + des3_decrypt_pubkey_ossh(keybuf, (unsigned char *)key->iv, key->keyblob, key->keyblob_len); memset(&md5c, 0, sizeof(md5c)); @@ -447,12 +559,14 @@ struct ssh2_userkey *openssh_read(char *filename, char *passphrase) 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. */ blobsize = 256+key->keyblob_len; - blob = smalloc(blobsize); + blob = snewn(blobsize, unsigned char); PUT_32BIT(blob, 7); if (key->type == OSSH_DSA) memcpy(blob+4, "ssh-dss", 7); @@ -468,6 +582,7 @@ struct ssh2_userkey *openssh_read(char *filename, char *passphrase) if (ret < 0 || id != 2 || key->keyblob+key->keyblob_len-p < len) { errmsg = "ASN.1 decoding failure"; + retval = SSH2_WRONG_PASSPHRASE; goto error; } @@ -488,7 +603,7 @@ struct ssh2_userkey *openssh_read(char *filename, char *passphrase) */ 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); @@ -524,7 +639,7 @@ struct ssh2_userkey *openssh_read(char *filename, char *passphrase) * 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); @@ -550,6 +665,247 @@ struct ssh2_userkey *openssh_read(char *filename, char *passphrase) 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; + + 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; + + 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! */ + } + + /* + * 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. + */ + 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); + + memset(&md5c, 0, sizeof(md5c)); + memset(keybuf, 0, 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"); /* 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) { + memset(outblob, 0, outlen); + sfree(outblob); + } + if (spareblob) { + memset(spareblob, 0, sparelen); + sfree(spareblob); + } + if (privblob) { + memset(privblob, 0, privlen); + sfree(privblob); + } + if (pubblob) { + memset(pubblob, 0, publen); + sfree(pubblob); + } + return ret; +} + /* ---------------------------------------------------------------------- * Code to read ssh.com private keys. */ @@ -624,13 +980,15 @@ struct ssh2_userkey *openssh_read(char *filename, char *passphrase) * 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; }; -struct sshcom_key *load_sshcom_key(char *filename) +static struct sshcom_key *load_sshcom_key(const Filename *filename) { struct sshcom_key *ret; FILE *fp; @@ -641,12 +999,12 @@ struct sshcom_key *load_sshcom_key(char *filename) char base64_bit[4]; int base64_chars = 0; - ret = smalloc(sizeof(*ret)); + ret = snew(struct sshcom_key); ret->comment[0] = '\0'; ret->keyblob = NULL; ret->keyblob_len = ret->keyblob_size = 0; - fp = fopen(filename, "r"); + fp = f_open(*filename, "r"); if (!fp) { errmsg = "Unable to open key file"; goto error; @@ -676,9 +1034,9 @@ struct sshcom_key *load_sshcom_key(char *filename) * Header lines can end in a trailing backslash for * continuation. */ - while ((len = strlen(p)) > sizeof(buffer) - (p-buffer) -1 || + while ((len = strlen(p)) > (int)(sizeof(buffer) - (p-buffer) -1) || p[len-1] != '\n' || p[len-2] == '\\') { - if (len > (p-buffer) + sizeof(buffer)-2) { + if (len > (int)((p-buffer) + sizeof(buffer)-2)) { errmsg = "Header line too long to deal with"; goto error; } @@ -717,7 +1075,8 @@ struct sshcom_key *load_sshcom_key(char *filename) if (ret->keyblob_len + len > ret->keyblob_size) { ret->keyblob_size = ret->keyblob_len + len + 256; - ret->keyblob = srealloc(ret->keyblob, ret->keyblob_size); + ret->keyblob = sresize(ret->keyblob, ret->keyblob_size, + unsigned char); } memcpy(ret->keyblob + ret->keyblob_len, out, len); @@ -748,7 +1107,7 @@ struct sshcom_key *load_sshcom_key(char *filename) return NULL; } -int sshcom_encrypted(char *filename, char **comment) +int sshcom_encrypted(const Filename *filename, char **comment) { struct sshcom_key *key = load_sshcom_key(filename); int pos, len, answer; @@ -788,9 +1147,7 @@ int sshcom_encrypted(char *filename, char **comment) return answer; } -struct mpint_pos { void *start; int bytes; }; - -int sshcom_read_mpint(void *data, int len, struct mpint_pos *ret) +static int sshcom_read_mpint(void *data, int len, struct mpint_pos *ret) { int bits; int bytes; @@ -814,7 +1171,25 @@ int sshcom_read_mpint(void *data, int len, struct mpint_pos *ret) return len; /* ensure further calls fail as well */ } -struct ssh2_userkey *sshcom_read(char *filename, char *passphrase) +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) { struct sshcom_key *key = load_sshcom_key(filename); char *errmsg; @@ -828,7 +1203,7 @@ struct ssh2_userkey *sshcom_read(char *filename, char *passphrase) struct ssh2_userkey *ret = NULL, *retkey; const struct ssh_signkey *alg; unsigned char *blob = NULL; - int blobsize, publen, privlen; + int blobsize = 0, publen, privlen; if (!key) return NULL; @@ -836,7 +1211,7 @@ struct ssh2_userkey *sshcom_read(char *filename, char *passphrase) /* * Check magic number. */ - if (GET_32BIT(key->keyblob) != 0x3f6ff9eb) { + if (GET_32BIT(key->keyblob) != SSHCOM_MAGIC_NUMBER) { errmsg = "Key does not begin with magic number"; goto error; } @@ -888,7 +1263,7 @@ struct ssh2_userkey *sshcom_read(char *filename, char *passphrase) errmsg = "Key blob does not contain actual key data"; goto error; } - ciphertext = key->keyblob + pos + 4; + ciphertext = (char *)key->keyblob + pos + 4; cipherlen = len; if (cipherlen == 0) { errmsg = "Length of key data is zero"; @@ -917,11 +1292,11 @@ struct ssh2_userkey *sshcom_read(char *filename, char *passphrase) } MD5Init(&md5c); - MD5Update(&md5c, passphrase, strlen(passphrase)); + MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); MD5Final(keybuf, &md5c); MD5Init(&md5c); - MD5Update(&md5c, passphrase, strlen(passphrase)); + MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); MD5Update(&md5c, keybuf, 16); MD5Final(keybuf+16, &md5c); @@ -929,7 +1304,8 @@ struct ssh2_userkey *sshcom_read(char *filename, char *passphrase) * Now decrypt the key blob. */ memset(iv, 0, sizeof(iv)); - des3_decrypt_pubkey_ossh(keybuf, iv, ciphertext, cipherlen); + des3_decrypt_pubkey_ossh(keybuf, iv, (unsigned char *)ciphertext, + cipherlen); memset(&md5c, 0, sizeof(md5c)); memset(keybuf, 0, sizeof(keybuf)); @@ -948,7 +1324,7 @@ struct ssh2_userkey *sshcom_read(char *filename, char *passphrase) * Strip away the containing string to get to the real meat. */ len = GET_32BIT(ciphertext); - if (len > cipherlen-4) { + if (len < 0 || len > cipherlen-4) { errmsg = "containing string was ill-formed"; goto error; } @@ -961,7 +1337,7 @@ struct ssh2_userkey *sshcom_read(char *filename, char *passphrase) * end up feeding them to alg->createkey(). */ blobsize = cipherlen + 256; - blob = smalloc(blobsize); + blob = snewn(blobsize, unsigned char); privlen = 0; if (type == RSA) { struct mpint_pos n, e, d, u, p, q; @@ -1015,11 +1391,12 @@ struct ssh2_userkey *sshcom_read(char *filename, char *passphrase) publen = pos; pos += put_mp(blob+pos, x.start, x.bytes); privlen = pos - publen; - } + } else + return NULL; assert(privlen > 0); /* should have bombed by now if not */ - retkey = smalloc(sizeof(struct ssh2_userkey)); + retkey = snew(struct ssh2_userkey); retkey->alg = alg; retkey->data = alg->createkey(blob, publen, blob+publen, privlen); if (!retkey->data) { @@ -1043,3 +1420,211 @@ struct ssh2_userkey *sshcom_read(char *filename, char *passphrase) sfree(key); 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; + + 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; + + 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! */ + } + + /* + * 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); + + memset(&md5c, 0, sizeof(md5c)); + memset(keybuf, 0, 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"); /* 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) { + memset(outblob, 0, outlen); + sfree(outblob); + } + if (privblob) { + memset(privblob, 0, privlen); + sfree(privblob); + } + if (pubblob) { + memset(pubblob, 0, publen); + sfree(pubblob); + } + return ret; +}