X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=sshpubk.c;h=1a27c313974506ec4fd9e6051b47e3f414a87c97;hb=510f49e405e71ba5c97875e7a019364e1ef5fac9;hp=86c9fc03a42849c2dc522622fc9b1e6854ba177c;hpb=6608016fc28d97e9fd5f53cfc671f9e7ccafd8ce;p=PuTTY.git diff --git a/sshpubk.c b/sshpubk.c index 86c9fc03..1a27c313 100644 --- a/sshpubk.c +++ b/sshpubk.c @@ -1,7 +1,7 @@ /* * Generic SSH public-key handling operations. In particular, * reading of SSH public-key files, and also the generic `sign' - * operation for ssh2 (which checks the type of the key and + * operation for SSH-2 (which checks the type of the key and * dispatches to the appropriate key-type specific function). */ @@ -9,21 +9,10 @@ #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) - -#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])) - #define rsa_signature "SSH PRIVATE KEY FILE FORMAT 1.1\n" #define BASE64_TOINT(x) ( (x)-'A'<26 ? (x)-'A'+0 :\ @@ -32,8 +21,11 @@ (x)=='+' ? 62 : \ (x)=='/' ? 63 : 0 ) -static int loadrsakey_main(FILE * fp, struct RSAKey *key, - char **commentptr, char *passphrase) +static int key_type_fp(FILE *fp); + +static int loadrsakey_main(FILE * fp, struct RSAKey *key, int pub_only, + char **commentptr, const char *passphrase, + const char **error) { unsigned char buf[16384]; unsigned char keybuf[16]; @@ -43,13 +35,18 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, struct MD5Context md5c; char *comment; + *error = NULL; + /* Slurp the whole file (minus the header) into a buffer. */ len = fread(buf, 1, sizeof(buf), fp); fclose(fp); - if (len < 0 || len == sizeof(buf)) + if (len < 0 || len == sizeof(buf)) { + *error = "error reading file"; goto end; /* file too big or not read */ + } i = 0; + *error = "file format error"; /* * A zero byte. (The signature includes a terminating NUL.) @@ -71,28 +68,39 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, || buf[i + 3] != 0) goto end; /* reserved field nonzero, panic! */ i += 4; - /* Now the serious stuff. An ordinary SSH 1 public key. */ - i += makekey(buf + i, key, NULL, 1); - if (len - i < 0) + /* Now the serious stuff. An ordinary SSH-1 public key. */ + j = makekey(buf + i, len - i, key, NULL, 1); + if (j < 0) goto end; /* overran */ + i += j; /* Next, the comment field. */ - j = GET_32BIT(buf + i); + j = toint(GET_32BIT(buf + i)); i += 4; - if (len - i < j) + if (j < 0 || len - i < j) goto end; - comment = smalloc(j + 1); + comment = snewn(j + 1, char); if (comment) { memcpy(comment, buf + i, j); comment[j] = '\0'; } i += j; if (commentptr) - *commentptr = comment; + *commentptr = dupstr(comment); if (key) key->comment = comment; + else + sfree(comment); + + if (pub_only) { + ret = 1; + goto end; + } + if (!key) { - return ciphertype != 0; + ret = ciphertype != 0; + *error = NULL; + goto end; } /* @@ -100,10 +108,10 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, */ if (ciphertype) { MD5Init(&md5c); - MD5Update(&md5c, passphrase, strlen(passphrase)); + MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); MD5Final(keybuf, &md5c); des3_decrypt_pubkey(keybuf, buf + i, (len - i + 7) & ~7); - memset(keybuf, 0, sizeof(keybuf)); /* burn the evidence */ + smemclr(keybuf, sizeof(keybuf)); /* burn the evidence */ } /* @@ -113,6 +121,7 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, if (len - i < 4) goto end; if (buf[i] != buf[i + 2] || buf[i + 1] != buf[i + 3]) { + *error = "wrong passphrase"; ret = -1; goto end; } @@ -123,64 +132,81 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, * decryption exponent, and then the three auxiliary values * (iqmp, q, p). */ - i += makeprivate(buf + i, key); - if (len - i < 0) - goto end; - i += ssh1_read_bignum(buf + i, &key->iqmp); - if (len - i < 0) - goto end; - i += ssh1_read_bignum(buf + i, &key->q); - if (len - i < 0) - goto end; - i += ssh1_read_bignum(buf + i, &key->p); - if (len - i < 0) - goto end; + j = makeprivate(buf + i, len - i, key); + if (j < 0) goto end; + i += j; + j = ssh1_read_bignum(buf + i, len - i, &key->iqmp); + if (j < 0) goto end; + i += j; + j = ssh1_read_bignum(buf + i, len - i, &key->q); + if (j < 0) goto end; + i += j; + j = ssh1_read_bignum(buf + i, len - i, &key->p); + if (j < 0) goto end; + i += j; if (!rsa_verify(key)) { + *error = "rsa_verify failed"; freersakey(key); ret = 0; } else ret = 1; end: - memset(buf, 0, sizeof(buf)); /* burn the evidence */ + smemclr(buf, sizeof(buf)); /* burn the evidence */ return ret; } -int loadrsakey(char *filename, struct RSAKey *key, char *passphrase) +int loadrsakey(const Filename *filename, struct RSAKey *key, + const char *passphrase, const char **errorstr) { FILE *fp; - unsigned char buf[64]; + char buf[64]; + int ret = 0; + const char *error = NULL; - fp = fopen(filename, "rb"); - if (!fp) - return 0; /* doesn't even exist */ + fp = f_open(filename, "rb", FALSE); + if (!fp) { + error = "can't open file"; + goto end; + } /* * Read the first line of the file and see if it's a v1 private * key file. */ if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) { - return loadrsakey_main(fp, key, NULL, passphrase); + /* + * This routine will take care of calling fclose() for us. + */ + ret = loadrsakey_main(fp, key, FALSE, NULL, passphrase, &error); + fp = NULL; + goto end; } /* * Otherwise, we have nothing. Return empty-handed. */ - fclose(fp); - return 0; + error = "not an SSH-1 RSA file"; + + end: + if (fp) + fclose(fp); + if ((ret != 1) && errorstr) + *errorstr = error; + return ret; } /* * See whether an RSA key is encrypted. Return its comment field as * well. */ -int rsakey_encrypted(char *filename, char **comment) +int rsakey_encrypted(const Filename *filename, char **comment) { FILE *fp; - unsigned char buf[64]; + char buf[64]; - fp = fopen(filename, "rb"); + fp = f_open(filename, "rb", FALSE); if (!fp) return 0; /* doesn't even exist */ @@ -189,16 +215,121 @@ int rsakey_encrypted(char *filename, char **comment) * key file. */ if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) { - return loadrsakey_main(fp, NULL, comment, NULL); + const char *dummy; + /* + * This routine will take care of calling fclose() for us. + */ + return loadrsakey_main(fp, NULL, FALSE, comment, NULL, &dummy); } fclose(fp); return 0; /* wasn't the right kind of file */ } +/* + * Return a malloc'ed chunk of memory containing the public blob of + * an RSA key, as given in the agent protocol (modulus bits, + * exponent, modulus). + */ +int rsakey_pubblob(const Filename *filename, void **blob, int *bloblen, + char **commentptr, const char **errorstr) +{ + FILE *fp; + char buf[64]; + struct RSAKey key; + int ret; + const char *error = NULL; + + /* Default return if we fail. */ + *blob = NULL; + *bloblen = 0; + ret = 0; + + fp = f_open(filename, "rb", FALSE); + if (!fp) { + error = "can't open file"; + goto end; + } + + /* + * Read the first line of the file and see if it's a v1 private + * key file. + */ + if (fgets(buf, sizeof(buf), fp) && !strcmp(buf, rsa_signature)) { + memset(&key, 0, sizeof(key)); + if (loadrsakey_main(fp, &key, TRUE, commentptr, NULL, &error)) { + *blob = rsa_public_blob(&key, bloblen); + freersakey(&key); + ret = 1; + } + fp = NULL; /* loadrsakey_main unconditionally closes fp */ + } else { + /* + * Try interpreting the file as an SSH-1 public key. + */ + char *line, *p, *bitsp, *expp, *modp, *commentp; + + rewind(fp); + line = chomp(fgetline(fp)); + p = line; + + bitsp = p; + p += strspn(p, "0123456789"); + if (*p != ' ') + goto not_public_either; + *p++ = '\0'; + + expp = p; + p += strspn(p, "0123456789"); + if (*p != ' ') + goto not_public_either; + *p++ = '\0'; + + modp = p; + p += strspn(p, "0123456789"); + if (*p) { + if (*p != ' ') + goto not_public_either; + *p++ = '\0'; + commentp = p; + } else { + commentp = NULL; + } + + memset(&key, 0, sizeof(key)); + key.exponent = bignum_from_decimal(expp); + key.modulus = bignum_from_decimal(modp); + if (atoi(bitsp) != bignum_bitcount(key.modulus)) { + freebn(key.exponent); + freebn(key.modulus); + sfree(line); + error = "key bit count does not match in SSH-1 public key file"; + goto end; + } + if (commentptr) + *commentptr = commentp ? dupstr(commentp) : NULL; + *blob = rsa_public_blob(&key, bloblen); + freersakey(&key); + sfree(line); + fclose(fp); + return 1; + + not_public_either: + sfree(line); + error = "not an SSH-1 RSA file"; + } + + end: + if (fp) + fclose(fp); + if ((ret != 1) && errorstr) + *errorstr = error; + return ret; +} + /* * Save an RSA key file. Return nonzero on success. */ -int saversakey(char *filename, struct RSAKey *key, char *passphrase) +int saversakey(const Filename *filename, struct RSAKey *key, char *passphrase) { unsigned char buf[16384]; unsigned char keybuf[16]; @@ -222,7 +353,7 @@ int saversakey(char *filename, struct RSAKey *key, char *passphrase) p += 4; /* - * An ordinary SSH 1 public key consists of: a uint32 + * An ordinary SSH-1 public key consists of: a uint32 * containing the bit count, then two bignums containing the * modulus and exponent respectively. */ @@ -279,30 +410,31 @@ int saversakey(char *filename, struct RSAKey *key, char *passphrase) */ if (passphrase) { MD5Init(&md5c); - MD5Update(&md5c, passphrase, strlen(passphrase)); + MD5Update(&md5c, (unsigned char *)passphrase, strlen(passphrase)); MD5Final(keybuf, &md5c); des3_encrypt_pubkey(keybuf, estart, p - estart); - memset(keybuf, 0, sizeof(keybuf)); /* burn the evidence */ + smemclr(keybuf, sizeof(keybuf)); /* burn the evidence */ } /* * Done. Write the result to the file. */ - fp = fopen(filename, "wb"); + fp = f_open(filename, "wb", TRUE); if (fp) { int ret = (fwrite(buf, 1, p - buf, fp) == (size_t) (p - buf)); - ret = ret && (fclose(fp) == 0); + if (fclose(fp)) + ret = 0; return ret; } else return 0; } /* ---------------------------------------------------------------------- - * SSH2 private key load/store functions. + * SSH-2 private key load/store functions. */ /* - * PuTTY's own format for SSH2 keys is as follows: + * PuTTY's own format for SSH-2 keys is as follows: * * The file is text. Lines are terminated by CRLF, although CR-only * and LF-only are tolerated on input. @@ -318,7 +450,7 @@ int saversakey(char *filename, struct RSAKey *key, char *passphrase) * * Next there is a line saying "Public-Lines: " plus a number N. * The following N lines contain a base64 encoding of the public - * part of the key. This is encoded as the standard SSH2 public key + * part of the key. This is encoded as the standard SSH-2 public key * blob (with no initial length): so for RSA, for example, it will * read * @@ -358,8 +490,7 @@ int saversakey(char *filename, struct RSAKey *key, char *passphrase) * data "putty-private-key-file-mac-key" * data passphrase * - * Encrypted keys should have a MAC, whereas unencrypted ones must - * have a hash. + * (An empty passphrase is used for unencrypted keys.) * * If the key is encrypted, the encryption key is derived from the * passphrase by means of a succession of SHA-1 hashes. Each hash @@ -376,10 +507,9 @@ int saversakey(char *filename, struct RSAKey *key, char *passphrase) * with "PuTTY-User-Key-File-1" (version number differs). In this * format the Private-MAC: field only covers the private-plaintext * field and nothing else (and without the 4-byte string length on - * the front too). Moreover, for RSA keys the Private-MAC: field - * can be replaced with a Private-Hash: field which is a plain - * SHA-1 hash instead of an HMAC. This is not allowable in DSA - * keys. (Yes, the old format was a mess. Guess why it changed :-) + * the front too). Moreover, the Private-MAC: field can be replaced + * with a Private-Hash: field which is a plain SHA-1 hash instead of + * an HMAC (this was generated for unencrypted keys). */ static int read_header(FILE * fp, char *header) @@ -387,7 +517,7 @@ static int read_header(FILE * fp, char *header) int len = 39; int c; - while (len > 0) { + while (1) { c = fgetc(fp); if (c == '\n' || c == '\r' || c == EOF) return 0; /* failure */ @@ -414,80 +544,30 @@ static char *read_body(FILE * fp) int c; size = 128; - text = smalloc(size); + text = snewn(size, char); len = 0; text[len] = '\0'; while (1) { c = fgetc(fp); - if (c == '\r' || c == '\n') { - c = fgetc(fp); - if (c != '\r' && c != '\n' && c != EOF) - ungetc(c, fp); + if (c == '\r' || c == '\n' || c == EOF) { + if (c != EOF) { + c = fgetc(fp); + if (c != '\r' && c != '\n') + ungetc(c, fp); + } return text; } - if (c == EOF) { - sfree(text); - return NULL; - } - if (len + 1 > size) { + if (len + 1 >= size) { size += 128; - text = srealloc(text, size); + text = sresize(text, size, char); } text[len++] = c; text[len] = '\0'; } } -int base64_decode_atom(char *atom, unsigned char *out) -{ - int vals[4]; - int i, v, len; - unsigned word; - char c; - - for (i = 0; i < 4; i++) { - c = atom[i]; - if (c >= 'A' && c <= 'Z') - v = c - 'A'; - else if (c >= 'a' && c <= 'z') - v = c - 'a' + 26; - else if (c >= '0' && c <= '9') - v = c - '0' + 52; - else if (c == '+') - v = 62; - else if (c == '/') - v = 63; - else if (c == '=') - v = -1; - else - return 0; /* invalid atom */ - vals[i] = v; - } - - if (vals[0] == -1 || vals[1] == -1) - return 0; - if (vals[2] == -1 && vals[3] != -1) - return 0; - - if (vals[3] != -1) - len = 3; - else if (vals[2] != -1) - len = 2; - else - len = 1; - - word = ((vals[0] << 18) | - (vals[1] << 12) | ((vals[2] & 0x3F) << 6) | (vals[3] & 0x3F)); - out[0] = (word >> 16) & 0xFF; - if (len > 1) - out[1] = (word >> 8) & 0xFF; - if (len > 2) - out[2] = word & 0xFF; - return len; -} - -static char *read_blob(FILE * fp, int nlines, int *bloblen) +static unsigned char *read_blob(FILE * fp, int nlines, int *bloblen) { unsigned char *blob; char *line; @@ -495,7 +575,7 @@ static char *read_blob(FILE * fp, int nlines, int *bloblen) int i, j, k; /* We expect at most 64 base64 characters, ie 48 real bytes, per line. */ - blob = smalloc(48 * nlines); + blob = snewn(48 * nlines, unsigned char); len = 0; for (i = 0; i < nlines; i++) { line = read_body(fp); @@ -531,7 +611,32 @@ struct ssh2_userkey ssh2_wrong_passphrase = { NULL, NULL, NULL }; -struct ssh2_userkey *ssh2_load_userkey(char *filename, char *passphrase) +const struct ssh_signkey *find_pubkey_alg_len(int namelen, const char *name) +{ + if (match_ssh_id(namelen, name, "ssh-rsa")) + return &ssh_rsa; + else if (match_ssh_id(namelen, name, "ssh-dss")) + return &ssh_dss; + else if (match_ssh_id(namelen, name, "ecdsa-sha2-nistp256")) + return &ssh_ecdsa_nistp256; + else if (match_ssh_id(namelen, name, "ecdsa-sha2-nistp384")) + return &ssh_ecdsa_nistp384; + else if (match_ssh_id(namelen, name, "ecdsa-sha2-nistp521")) + return &ssh_ecdsa_nistp521; + else if (match_ssh_id(namelen, name, "ssh-ed25519")) + return &ssh_ecdsa_ed25519; + else + return NULL; +} + +const struct ssh_signkey *find_pubkey_alg(const char *name) +{ + return find_pubkey_alg_len(strlen(name), name); +} + +struct ssh2_userkey *ssh2_load_userkey(const Filename *filename, + const char *passphrase, + const char **errorstr) { FILE *fp; char header[40], *b, *encryption, *comment, *mac; @@ -542,14 +647,17 @@ struct ssh2_userkey *ssh2_load_userkey(char *filename, char *passphrase) int public_blob_len, private_blob_len; int i, is_mac, old_fmt; int passlen = passphrase ? strlen(passphrase) : 0; + const char *error = NULL; ret = NULL; /* return NULL for most errors */ - comment = mac = NULL; + encryption = comment = mac = NULL; public_blob = private_blob = NULL; - fp = fopen(filename, "rb"); - if (!fp) + fp = f_open(filename, "rb", FALSE); + if (!fp) { + error = "can't open file"; goto error; + } /* Read the first header line which contains the key type. */ if (!read_header(fp, header)) @@ -560,16 +668,21 @@ struct ssh2_userkey *ssh2_load_userkey(char *filename, char *passphrase) /* this is an old key file; warn and then continue */ old_keyfile_warning(); old_fmt = 1; - } else + } else if (0 == strncmp(header, "PuTTY-User-Key-File-", 20)) { + /* this is a key file FROM THE FUTURE; refuse it, but with a + * more specific error message than the generic one below */ + error = "PuTTY key format too new"; + goto error; + } else { + error = "not a PuTTY SSH-2 private key"; goto error; + } + error = "file format error"; if ((b = read_body(fp)) == NULL) goto error; /* Select key algorithm structure. */ - if (!strcmp(b, "ssh-rsa")) - alg = &ssh_rsa; - else if (!strcmp(b, "ssh-dss")) - alg = &ssh_dss; - else { + alg = find_pubkey_alg(b); + if (!alg) { sfree(b); goto error; } @@ -587,7 +700,6 @@ struct ssh2_userkey *ssh2_load_userkey(char *filename, char *passphrase) cipher = 0; cipherblk = 1; } else { - sfree(encryption); goto error; } @@ -624,8 +736,7 @@ struct ssh2_userkey *ssh2_load_userkey(char *filename, char *passphrase) if ((mac = read_body(fp)) == NULL) goto error; is_mac = 1; - } else if (0 == strcmp(header, "Private-Hash") && - alg == &ssh_rsa && old_fmt) { + } else if (0 == strcmp(header, "Private-Hash") && old_fmt) { if ((mac = read_body(fp)) == NULL) goto error; is_mac = 0; @@ -683,7 +794,7 @@ struct ssh2_userkey *ssh2_load_userkey(char *filename, char *passphrase) 4 + commlen + 4 + public_blob_len + 4 + private_blob_len); - macdata = smalloc(maclen); + macdata = snewn(maclen, unsigned char); p = macdata; #define DO_STR(s,len) PUT_32BIT(p,(len));memcpy(p+4,(s),(len));p+=4+(len) DO_STR(alg->name, namelen); @@ -702,20 +813,20 @@ struct ssh2_userkey *ssh2_load_userkey(char *filename, char *passphrase) SHA_Init(&s); SHA_Bytes(&s, header, sizeof(header)-1); - if (passphrase) + if (cipher && passphrase) SHA_Bytes(&s, passphrase, passlen); SHA_Final(&s, mackey); hmac_sha1_simple(mackey, 20, macdata, maclen, binary); - memset(mackey, 0, sizeof(mackey)); - memset(&s, 0, sizeof(s)); + smemclr(mackey, sizeof(mackey)); + smemclr(&s, sizeof(s)); } else { SHA_Simple(macdata, maclen, binary); } if (free_macdata) { - memset(macdata, 0, maclen); + smemclr(macdata, maclen); sfree(macdata); } @@ -725,28 +836,39 @@ struct ssh2_userkey *ssh2_load_userkey(char *filename, char *passphrase) if (strcmp(mac, realmac)) { /* An incorrect MAC is an unconditional Error if the key is * unencrypted. Otherwise, it means Wrong Passphrase. */ - ret = cipher ? SSH2_WRONG_PASSPHRASE : NULL; + if (cipher) { + error = "wrong passphrase"; + ret = SSH2_WRONG_PASSPHRASE; + } else { + error = "MAC failed"; + ret = NULL; + } goto error; } } sfree(mac); + mac = NULL; /* * Create and return the key. */ - ret = smalloc(sizeof(struct ssh2_userkey)); + ret = snew(struct ssh2_userkey); ret->alg = alg; ret->comment = comment; - ret->data = alg->createkey(public_blob, public_blob_len, + ret->data = alg->createkey(alg, public_blob, public_blob_len, private_blob, private_blob_len); if (!ret->data) { - sfree(ret->comment); sfree(ret); ret = NULL; + error = "createkey failed"; + goto error; } sfree(public_blob); + smemclr(private_blob, private_blob_len); sfree(private_blob); sfree(encryption); + if (errorstr) + *errorstr = NULL; return ret; /* @@ -763,44 +885,283 @@ struct ssh2_userkey *ssh2_load_userkey(char *filename, char *passphrase) sfree(mac); if (public_blob) sfree(public_blob); - if (private_blob) - sfree(private_blob); + if (private_blob) { + smemclr(private_blob, private_blob_len); + sfree(private_blob); + } + if (errorstr) + *errorstr = error; return ret; } -char *ssh2_userkey_loadpub(char *filename, char **algorithm, - int *pub_blob_len) +unsigned char *rfc4716_loadpub(FILE *fp, char **algorithm, + int *pub_blob_len, char **commentptr, + const char **errorstr) +{ + const char *error; + char *line, *colon, *value; + char *comment = NULL; + unsigned char *pubblob = NULL; + int pubbloblen, pubblobsize; + char base64in[4]; + unsigned char base64out[3]; + int base64bytes; + int alglen; + + line = chomp(fgetline(fp)); + if (!line || 0 != strcmp(line, "---- BEGIN SSH2 PUBLIC KEY ----")) { + error = "invalid begin line in SSH-2 public key file"; + goto error; + } + sfree(line); line = NULL; + + while (1) { + line = chomp(fgetline(fp)); + if (!line) { + error = "truncated SSH-2 public key file"; + goto error; + } + colon = strstr(line, ": "); + if (!colon) + break; + *colon = '\0'; + value = colon + 2; + + if (!strcmp(line, "Comment")) { + char *p, *q; + + /* Remove containing double quotes, if present */ + p = value; + if (*p == '"' && p[strlen(p)-1] == '"') { + p[strlen(p)-1] = '\0'; + p++; + } + + /* Remove \-escaping, not in RFC4716 but seen in the wild + * in practice. */ + for (q = line; *p; p++) { + if (*p == '\\' && p[1]) + p++; + *q++ = *p; + } + + *q = '\0'; + sfree(comment); /* *just* in case of multiple Comment headers */ + comment = dupstr(line); + } else if (!strcmp(line, "Subject") || + !strncmp(line, "x-", 2)) { + /* Headers we recognise and ignore. Do nothing. */ + } else { + error = "unrecognised header in SSH-2 public key file"; + goto error; + } + + sfree(line); line = NULL; + } + + /* + * Now line contains the initial line of base64 data. Loop round + * while it still does contain base64. + */ + pubblobsize = 4096; + pubblob = snewn(pubblobsize, unsigned char); + pubbloblen = 0; + base64bytes = 0; + while (line && line[0] != '-') { + char *p; + for (p = line; *p; p++) { + base64in[base64bytes++] = *p; + if (base64bytes == 4) { + int n = base64_decode_atom(base64in, base64out); + if (pubbloblen + n > pubblobsize) { + pubblobsize = (pubbloblen + n) * 5 / 4 + 1024; + pubblob = sresize(pubblob, pubblobsize, unsigned char); + } + memcpy(pubblob + pubbloblen, base64out, n); + pubbloblen += n; + base64bytes = 0; + } + } + sfree(line); line = NULL; + line = chomp(fgetline(fp)); + } + + /* + * Finally, check the END line makes sense. + */ + if (!line || 0 != strcmp(line, "---- END SSH2 PUBLIC KEY ----")) { + error = "invalid end line in SSH-2 public key file"; + goto error; + } + sfree(line); line = NULL; + + /* + * OK, we now have a public blob and optionally a comment. We must + * return the key algorithm string too, so look for that at the + * start of the public blob. + */ + if (pubbloblen < 4) { + error = "not enough data in SSH-2 public key file"; + goto error; + } + alglen = toint(GET_32BIT(pubblob)); + if (alglen < 0 || alglen > pubbloblen-4) { + error = "invalid algorithm prefix in SSH-2 public key file"; + goto error; + } + if (algorithm) + *algorithm = dupprintf("%.*s", alglen, pubblob+4); + if (pub_blob_len) + *pub_blob_len = pubbloblen; + if (commentptr) + *commentptr = comment; + else + sfree(comment); + return pubblob; + + error: + sfree(line); + sfree(comment); + sfree(pubblob); + if (errorstr) + *errorstr = error; + return NULL; +} + +unsigned char *openssh_loadpub(FILE *fp, char **algorithm, + int *pub_blob_len, char **commentptr, + const char **errorstr) +{ + const char *error; + char *line, *base64; + char *comment = NULL; + unsigned char *pubblob = NULL; + int pubbloblen, pubblobsize; + int alglen; + + line = chomp(fgetline(fp)); + + base64 = strchr(line, ' '); + if (!base64) { + error = "no key blob in OpenSSH public key file"; + goto error; + } + *base64++ = '\0'; + + comment = strchr(base64, ' '); + if (comment) { + *comment++ = '\0'; + comment = dupstr(comment); + } + + pubblobsize = strlen(base64) / 4 * 3; + pubblob = snewn(pubblobsize, unsigned char); + pubbloblen = 0; + + while (!memchr(base64, '\0', 4)) { + assert(pubbloblen + 3 <= pubblobsize); + pubbloblen += base64_decode_atom(base64, pubblob + pubbloblen); + base64 += 4; + } + if (*base64) { + error = "invalid length for base64 data in OpenSSH public key file"; + goto error; + } + + /* + * Sanity check: the first word on the line should be the key + * algorithm, and should match the encoded string at the start of + * the public blob. + */ + alglen = strlen(line); + if (pubbloblen < alglen + 4 || + GET_32BIT(pubblob) != alglen || + 0 != memcmp(pubblob + 4, line, alglen)) { + error = "key algorithms do not match in OpenSSH public key file"; + goto error; + } + + /* + * Done. + */ + if (algorithm) + *algorithm = dupstr(line); + if (pub_blob_len) + *pub_blob_len = pubbloblen; + if (commentptr) + *commentptr = comment; + else + sfree(comment); + sfree(line); + return pubblob; + + error: + sfree(line); + sfree(comment); + sfree(pubblob); + if (errorstr) + *errorstr = error; + return NULL; +} + +unsigned char *ssh2_userkey_loadpub(const Filename *filename, char **algorithm, + int *pub_blob_len, char **commentptr, + const char **errorstr) { FILE *fp; char header[40], *b; const struct ssh_signkey *alg; unsigned char *public_blob; int public_blob_len; - int i; + int type, i; + const char *error = NULL; + char *comment = NULL; public_blob = NULL; - fp = fopen(filename, "rb"); - if (!fp) + fp = f_open(filename, "rb", FALSE); + if (!fp) { + error = "can't open file"; goto error; + } + + /* Initially, check if this is a public-only key file. Sometimes + * we'll be asked to read a public blob from one of those. */ + type = key_type_fp(fp); + if (type == SSH_KEYTYPE_SSH2_PUBLIC_RFC4716) { + unsigned char *ret = rfc4716_loadpub(fp, algorithm, pub_blob_len, + commentptr, errorstr); + fclose(fp); + return ret; + } else if (type == SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH) { + unsigned char *ret = openssh_loadpub(fp, algorithm, pub_blob_len, + commentptr, errorstr); + fclose(fp); + return ret; + } else if (type != SSH_KEYTYPE_SSH2) { + error = "not a PuTTY SSH-2 private key"; + goto error; + } /* Read the first header line which contains the key type. */ if (!read_header(fp, header) || (0 != strcmp(header, "PuTTY-User-Key-File-2") && - 0 != strcmp(header, "PuTTY-User-Key-File-1"))) + 0 != strcmp(header, "PuTTY-User-Key-File-1"))) { + if (0 == strncmp(header, "PuTTY-User-Key-File-", 20)) + error = "PuTTY key format too new"; + else + error = "not a PuTTY SSH-2 private key"; goto error; + } + error = "file format error"; if ((b = read_body(fp)) == NULL) goto error; - /* Select key algorithm structure. Currently only ssh-rsa. */ - if (!strcmp(b, "ssh-rsa")) - alg = &ssh_rsa; - else if (!strcmp(b, "ssh-dss")) - alg = &ssh_dss; - else { - sfree(b); + /* Select key algorithm structure. */ + alg = find_pubkey_alg(b); + sfree(b); + if (!alg) { goto error; } - sfree(b); /* Read the Encryption header line. */ if (!read_header(fp, header) || 0 != strcmp(header, "Encryption")) @@ -812,9 +1173,13 @@ char *ssh2_userkey_loadpub(char *filename, char **algorithm, /* Read the Comment header line. */ if (!read_header(fp, header) || 0 != strcmp(header, "Comment")) goto error; - if ((b = read_body(fp)) == NULL) + if ((comment = read_body(fp)) == NULL) goto error; - sfree(b); /* we don't care */ + + if (commentptr) + *commentptr = comment; + else + sfree(comment); /* Read the Public-Lines header line and the public blob. */ if (!read_header(fp, header) || 0 != strcmp(header, "Public-Lines")) @@ -827,8 +1192,10 @@ char *ssh2_userkey_loadpub(char *filename, char **algorithm, goto error; fclose(fp); - *pub_blob_len = public_blob_len; - *algorithm = alg->name; + if (pub_blob_len) + *pub_blob_len = public_blob_len; + if (algorithm) + *algorithm = dupstr(alg->name); return public_blob; /* @@ -839,10 +1206,16 @@ char *ssh2_userkey_loadpub(char *filename, char **algorithm, fclose(fp); if (public_blob) sfree(public_blob); + if (errorstr) + *errorstr = error; + if (comment && commentptr) { + sfree(comment); + *commentptr = NULL; + } return NULL; } -int ssh2_userkey_encrypted(char *filename, char **commentptr) +int ssh2_userkey_encrypted(const Filename *filename, char **commentptr) { FILE *fp; char header[40], *b, *comment; @@ -851,7 +1224,7 @@ int ssh2_userkey_encrypted(char *filename, char **commentptr) if (commentptr) *commentptr = NULL; - fp = fopen(filename, "rb"); + fp = f_open(filename, "rb", FALSE); if (!fp) return 0; if (!read_header(fp, header) @@ -889,6 +1262,8 @@ int ssh2_userkey_encrypted(char *filename, char **commentptr) if (commentptr) *commentptr = comment; + else + sfree(comment); fclose(fp); if (!strcmp(b, "aes256-cbc")) @@ -905,52 +1280,30 @@ int base64_lines(int datalen) return (datalen + 47) / 48; } -void base64_encode_atom(unsigned char *data, int n, char *out) -{ - static const char base64_chars[] = - "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; - - unsigned word; - - word = data[0] << 16; - if (n > 1) - word |= data[1] << 8; - if (n > 2) - word |= data[2]; - out[0] = base64_chars[(word >> 18) & 0x3F]; - out[1] = base64_chars[(word >> 12) & 0x3F]; - if (n > 1) - out[2] = base64_chars[(word >> 6) & 0x3F]; - else - out[2] = '='; - if (n > 2) - out[3] = base64_chars[word & 0x3F]; - else - out[3] = '='; -} - -void base64_encode(FILE * fp, unsigned char *data, int datalen) +void base64_encode(FILE *fp, const unsigned char *data, int datalen, int cpl) { int linelen = 0; char out[4]; - int n; + int n, i; while (datalen > 0) { - if (linelen >= 64) { - linelen = 0; - fputc('\n', fp); - } n = (datalen < 3 ? datalen : 3); base64_encode_atom(data, n, out); data += n; datalen -= n; - fwrite(out, 1, 4, fp); - linelen += 4; + for (i = 0; i < 4; i++) { + if (linelen >= cpl) { + linelen = 0; + fputc('\n', fp); + } + fputc(out[i], fp); + linelen++; + } } fputc('\n', fp); } -int ssh2_save_userkey(char *filename, struct ssh2_userkey *key, +int ssh2_save_userkey(const Filename *filename, struct ssh2_userkey *key, char *passphrase) { FILE *fp; @@ -959,7 +1312,7 @@ int ssh2_save_userkey(char *filename, struct ssh2_userkey *key, int passlen; int cipherblk; int i; - char *cipherstr; + const char *cipherstr; unsigned char priv_mac[20]; /* @@ -985,7 +1338,7 @@ int ssh2_save_userkey(char *filename, struct ssh2_userkey *key, } priv_encrypted_len = priv_blob_len + cipherblk - 1; priv_encrypted_len -= priv_encrypted_len % cipherblk; - priv_blob_encrypted = smalloc(priv_encrypted_len); + priv_blob_encrypted = snewn(priv_encrypted_len, unsigned char); memset(priv_blob_encrypted, 0, priv_encrypted_len); memcpy(priv_blob_encrypted, priv_blob, priv_blob_len); /* Create padding based on the SHA hash of the unpadded blob. This prevents @@ -1012,7 +1365,7 @@ int ssh2_save_userkey(char *filename, struct ssh2_userkey *key, 4 + commlen + 4 + pub_blob_len + 4 + priv_encrypted_len); - macdata = smalloc(maclen); + macdata = snewn(maclen, unsigned char); p = macdata; #define DO_STR(s,len) PUT_32BIT(p,(len));memcpy(p+4,(s),(len));p+=4+(len) DO_STR(key->alg->name, namelen); @@ -1027,14 +1380,14 @@ int ssh2_save_userkey(char *filename, struct ssh2_userkey *key, SHA_Bytes(&s, passphrase, strlen(passphrase)); SHA_Final(&s, mackey); hmac_sha1_simple(mackey, 20, macdata, maclen, priv_mac); - memset(macdata, 0, maclen); + smemclr(macdata, maclen); sfree(macdata); - memset(mackey, 0, sizeof(mackey)); - memset(&s, 0, sizeof(s)); + smemclr(mackey, sizeof(mackey)); + smemclr(&s, sizeof(s)); } if (passphrase) { - char key[40]; + unsigned char key[40]; SHA_State s; passlen = strlen(passphrase); @@ -1050,20 +1403,26 @@ int ssh2_save_userkey(char *filename, struct ssh2_userkey *key, aes256_encrypt_pubkey(key, priv_blob_encrypted, priv_encrypted_len); - memset(key, 0, sizeof(key)); - memset(&s, 0, sizeof(s)); + smemclr(key, sizeof(key)); + smemclr(&s, sizeof(s)); } - fp = fopen(filename, "w"); - if (!fp) - return 0; + fp = f_open(filename, "w", TRUE); + if (!fp) { + sfree(pub_blob); + smemclr(priv_blob, priv_blob_len); + sfree(priv_blob); + smemclr(priv_blob_encrypted, priv_blob_len); + sfree(priv_blob_encrypted); + return 0; + } fprintf(fp, "PuTTY-User-Key-File-2: %s\n", key->alg->name); fprintf(fp, "Encryption: %s\n", cipherstr); fprintf(fp, "Comment: %s\n", key->comment); fprintf(fp, "Public-Lines: %d\n", base64_lines(pub_blob_len)); - base64_encode(fp, pub_blob, pub_blob_len); + base64_encode(fp, pub_blob, pub_blob_len, 64); fprintf(fp, "Private-Lines: %d\n", base64_lines(priv_encrypted_len)); - base64_encode(fp, priv_blob_encrypted, priv_encrypted_len); + base64_encode(fp, priv_blob_encrypted, priv_encrypted_len, 64); fprintf(fp, "Private-MAC: "); for (i = 0; i < 20; i++) fprintf(fp, "%02x", priv_mac[i]); @@ -1071,29 +1430,288 @@ int ssh2_save_userkey(char *filename, struct ssh2_userkey *key, fclose(fp); sfree(pub_blob); - memset(priv_blob, 0, priv_blob_len); + smemclr(priv_blob, priv_blob_len); sfree(priv_blob); + smemclr(priv_blob_encrypted, priv_blob_len); sfree(priv_blob_encrypted); return 1; } /* ---------------------------------------------------------------------- - * A function to determine which version of SSH to try on a private - * key file. Returns 0 on failure, 1 or 2 on success. + * Output public keys. */ -int keyfile_version(char *filename) +char *ssh1_pubkey_str(struct RSAKey *key) { - FILE *fp; + char *buffer; + char *dec1, *dec2; + + dec1 = bignum_decimal(key->exponent); + dec2 = bignum_decimal(key->modulus); + buffer = dupprintf("%d %s %s%s%s", bignum_bitcount(key->modulus), + dec1, dec2, + key->comment ? " " : "", + key->comment ? key->comment : ""); + sfree(dec1); + sfree(dec2); + return buffer; +} + +void ssh1_write_pubkey(FILE *fp, struct RSAKey *key) +{ + char *buffer = ssh1_pubkey_str(key); + fprintf(fp, "%s\n", buffer); + sfree(buffer); +} + +static char *ssh2_pubkey_openssh_str_internal(const char *comment, + const void *v_pub_blob, + int pub_len) +{ + const unsigned char *ssh2blob = (const unsigned char *)v_pub_blob; + const char *alg; + int alglen; + char *buffer, *p; + int i; + + if (pub_len < 4) { + alg = NULL; + } else { + alglen = GET_32BIT(ssh2blob); + if (alglen > 0 && alglen < pub_len - 4) { + alg = (const char *)ssh2blob + 4; + } else { + alg = NULL; + } + } + + if (!alg) { + alg = "INVALID-ALGORITHM"; + alglen = strlen(alg); + } + + buffer = snewn(alglen + + 4 * ((pub_len+2) / 3) + + (comment ? strlen(comment) : 0) + 3, char); + p = buffer + sprintf(buffer, "%.*s ", alglen, alg); + i = 0; + while (i < pub_len) { + int n = (pub_len - i < 3 ? pub_len - i : 3); + base64_encode_atom(ssh2blob + i, n, p); + i += n; + p += 4; + } + if (*comment) { + *p++ = ' '; + strcpy(p, comment); + } else + *p++ = '\0'; + + return buffer; +} + +char *ssh2_pubkey_openssh_str(struct ssh2_userkey *key) +{ + int bloblen; + unsigned char *blob; + char *ret; + + blob = key->alg->public_blob(key->data, &bloblen); + ret = ssh2_pubkey_openssh_str_internal(key->comment, blob, bloblen); + sfree(blob); + + return ret; +} + +void ssh2_write_pubkey(FILE *fp, const char *comment, + const void *v_pub_blob, int pub_len, + int keytype) +{ + unsigned char *pub_blob = (unsigned char *)v_pub_blob; + + if (keytype == SSH_KEYTYPE_SSH2_PUBLIC_RFC4716) { + const char *p; + int i, column; + + fprintf(fp, "---- BEGIN SSH2 PUBLIC KEY ----\n"); + + if (comment) { + fprintf(fp, "Comment: \""); + for (p = comment; *p; p++) { + if (*p == '\\' || *p == '\"') + fputc('\\', fp); + fputc(*p, fp); + } + fprintf(fp, "\"\n"); + } + + i = 0; + column = 0; + while (i < pub_len) { + char buf[5]; + int n = (pub_len - i < 3 ? pub_len - i : 3); + base64_encode_atom(pub_blob + i, n, buf); + i += n; + buf[4] = '\0'; + fputs(buf, fp); + if (++column >= 16) { + fputc('\n', fp); + column = 0; + } + } + if (column > 0) + fputc('\n', fp); + + fprintf(fp, "---- END SSH2 PUBLIC KEY ----\n"); + } else if (keytype == SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH) { + char *buffer = ssh2_pubkey_openssh_str_internal(comment, + v_pub_blob, pub_len); + fprintf(fp, "%s\n", buffer); + sfree(buffer); + } else { + assert(0 && "Bad key type in ssh2_write_pubkey"); + } +} + +/* ---------------------------------------------------------------------- + * Utility functions to compute SSH-2 fingerprints in a uniform way. + */ +char *ssh2_fingerprint_blob(const void *blob, int bloblen) +{ + unsigned char digest[16]; + char fingerprint_str[16*3]; + const char *algstr; + int alglen; + const struct ssh_signkey *alg; + int i; + + /* + * The fingerprint hash itself is always just the MD5 of the blob. + */ + MD5Simple(blob, bloblen, digest); + for (i = 0; i < 16; i++) + sprintf(fingerprint_str + i*3, "%02x%s", digest[i], i==15 ? "" : ":"); + + /* + * Identify the key algorithm, if possible. + */ + alglen = toint(GET_32BIT((const unsigned char *)blob)); + if (alglen > 0 && alglen < bloblen-4) { + algstr = (const char *)blob + 4; + + /* + * If we can actually identify the algorithm as one we know + * about, get hold of the key's bit count too. + */ + alg = find_pubkey_alg_len(alglen, algstr); + if (alg) { + int bits = alg->pubkey_bits(alg, blob, bloblen); + return dupprintf("%.*s %d %s", alglen, algstr, + bits, fingerprint_str); + } else { + return dupprintf("%.*s %s", alglen, algstr, fingerprint_str); + } + } else { + /* + * No algorithm available (which means a seriously confused + * key blob, but there we go). Return only the hash. + */ + return dupstr(fingerprint_str); + } +} + +char *ssh2_fingerprint(const struct ssh_signkey *alg, void *data) +{ + int len; + unsigned char *blob = alg->public_blob(data, &len); + char *ret = ssh2_fingerprint_blob(blob, len); + sfree(blob); + return ret; +} + +/* ---------------------------------------------------------------------- + * Determine the type of a private key file. + */ +static int key_type_fp(FILE *fp) +{ + char buf[1024]; + const char public_std_sig[] = "---- BEGIN SSH2 PUBLIC KEY"; + const char putty2_sig[] = "PuTTY-User-Key-File-"; + const char sshcom_sig[] = "---- BEGIN SSH2 ENCRYPTED PRIVAT"; + const char openssh_new_sig[] = "-----BEGIN OPENSSH PRIVATE KEY"; + const char openssh_sig[] = "-----BEGIN "; int i; + char *p; + + i = fread(buf, 1, sizeof(buf)-1, fp); + rewind(fp); + + if (i < 0) + return SSH_KEYTYPE_UNOPENABLE; + if (i < 32) + return SSH_KEYTYPE_UNKNOWN; + assert(i > 0 && i < sizeof(buf)); + buf[i] = '\0'; + if (!memcmp(buf, rsa_signature, sizeof(rsa_signature)-1)) + return SSH_KEYTYPE_SSH1; + if (!memcmp(buf, public_std_sig, sizeof(public_std_sig)-1)) + return SSH_KEYTYPE_SSH2_PUBLIC_RFC4716; + if (!memcmp(buf, putty2_sig, sizeof(putty2_sig)-1)) + return SSH_KEYTYPE_SSH2; + if (!memcmp(buf, openssh_new_sig, sizeof(openssh_new_sig)-1)) + return SSH_KEYTYPE_OPENSSH_NEW; + if (!memcmp(buf, openssh_sig, sizeof(openssh_sig)-1)) + return SSH_KEYTYPE_OPENSSH_PEM; + if (!memcmp(buf, sshcom_sig, sizeof(sshcom_sig)-1)) + return SSH_KEYTYPE_SSHCOM; + if ((p = buf + strspn(buf, "0123456789"), *p == ' ') && + (p = p+1 + strspn(p+1, "0123456789"), *p == ' ') && + (p = p+1 + strspn(p+1, "0123456789"), *p == ' ' || *p == '\n' || !*p)) + return SSH_KEYTYPE_SSH1_PUBLIC; + if ((p = buf + strcspn(buf, " "), find_pubkey_alg_len(p-buf, buf)) && + (p = p+1 + strspn(p+1, "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghij" + "klmnopqrstuvwxyz+/="), + *p == ' ' || *p == '\n' || !*p)) + return SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH; + return SSH_KEYTYPE_UNKNOWN; /* unrecognised or EOF */ +} + +int key_type(const Filename *filename) +{ + FILE *fp; + int ret; - fp = fopen(filename, "r"); + fp = f_open(filename, "r", FALSE); if (!fp) - return 0; - i = fgetc(fp); + return SSH_KEYTYPE_UNOPENABLE; + ret = key_type_fp(fp); fclose(fp); - if (i == 'S') - return 1; /* "SSH PRIVATE KEY FORMAT" etc */ - if (i == 'P') /* "PuTTY-User-Key-File" etc */ - return 2; - return 0; /* unrecognised or EOF */ + return ret; +} + +/* + * Convert the type word to a string, for `wrong type' error + * messages. + */ +const char *key_type_to_str(int type) +{ + switch (type) { + case SSH_KEYTYPE_UNOPENABLE: return "unable to open file"; break; + case SSH_KEYTYPE_UNKNOWN: return "not a recognised key file format"; break; + case SSH_KEYTYPE_SSH1_PUBLIC: return "SSH-1 public key"; break; + case SSH_KEYTYPE_SSH2_PUBLIC_RFC4716: return "SSH-2 public key (RFC 4716 format)"; break; + case SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH: return "SSH-2 public key (OpenSSH format)"; break; + case SSH_KEYTYPE_SSH1: return "SSH-1 private key"; break; + case SSH_KEYTYPE_SSH2: return "PuTTY SSH-2 private key"; break; + case SSH_KEYTYPE_OPENSSH_PEM: return "OpenSSH SSH-2 private key (old PEM format)"; break; + case SSH_KEYTYPE_OPENSSH_NEW: return "OpenSSH SSH-2 private key (new format)"; break; + case SSH_KEYTYPE_SSHCOM: return "ssh.com SSH-2 private key"; break; + /* + * This function is called with a key type derived from + * looking at an actual key file, so the output-only type + * OPENSSH_AUTO should never get here, and is much an INTERNAL + * ERROR as a code we don't even understand. + */ + case SSH_KEYTYPE_OPENSSH_AUTO: return "INTERNAL ERROR (OPENSSH_AUTO)"; break; + default: return "INTERNAL ERROR"; break; + } }