X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/7bedb13c064e90654b709137a01c6feaee7a3abe..2d8cd396ba55fad14d7e03ae904d9fe8fdf1b60d:/sshpubk.c diff --git a/sshpubk.c b/sshpubk.c index 86c9fc03..dd06ebd5 100644 --- a/sshpubk.c +++ b/sshpubk.c @@ -9,6 +9,7 @@ #include #include +#include "putty.h" #include "ssh.h" #include "misc.h" @@ -32,8 +33,9 @@ (x)=='+' ? 62 : \ (x)=='/' ? 63 : 0 ) -static int loadrsakey_main(FILE * fp, struct RSAKey *key, - char **commentptr, char *passphrase) +static int loadrsakey_main(FILE * fp, struct RSAKey *key, int pub_only, + char **commentptr, char *passphrase, + const char **error) { unsigned char buf[16384]; unsigned char keybuf[16]; @@ -43,13 +45,18 @@ 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.) @@ -76,12 +83,17 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, if (len - i < 0) goto end; /* overran */ + if (pub_only) { + ret = 1; + goto end; + } + /* Next, the comment field. */ j = GET_32BIT(buf + i); i += 4; if (len - i < j) goto end; - comment = smalloc(j + 1); + comment = snewn(j + 1, char); if (comment) { memcpy(comment, buf + i, j); comment[j] = '\0'; @@ -92,7 +104,9 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, if (key) key->comment = comment; if (!key) { - return ciphertype != 0; + ret = ciphertype != 0; + *error = NULL; + goto end; } /* @@ -100,7 +114,7 @@ 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 */ @@ -113,6 +127,7 @@ 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; } @@ -137,6 +152,7 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, goto end; if (!rsa_verify(key)) { + *error = "rsa_verify failed"; freersakey(key); ret = 0; } else @@ -147,40 +163,51 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, return ret; } -int loadrsakey(char *filename, struct RSAKey *key, char *passphrase) +int loadrsakey(const Filename *filename, struct RSAKey *key, 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"); + 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); + ret = loadrsakey_main(fp, key, FALSE, NULL, passphrase, &error); + goto end; } /* * Otherwise, we have nothing. Return empty-handed. */ fclose(fp); - return 0; + error = "not an SSH-1 RSA file"; + + end: + 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"); if (!fp) return 0; /* doesn't even exist */ @@ -189,16 +216,64 @@ 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; + 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, + 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"); + 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, NULL, NULL, &error)) { + *blob = rsa_public_blob(&key, bloblen); + freersakey(&key); + ret = 1; + } + } else { + error = "not an SSH-1 RSA file"; + fclose(fp); + } + + end: + 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]; @@ -279,7 +354,7 @@ 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 */ @@ -288,7 +363,7 @@ int saversakey(char *filename, struct RSAKey *key, char *passphrase) /* * Done. Write the result to the file. */ - fp = fopen(filename, "wb"); + fp = f_open(*filename, "wb"); if (fp) { int ret = (fwrite(buf, 1, p - buf, fp) == (size_t) (p - buf)); ret = ret && (fclose(fp) == 0); @@ -358,8 +433,7 @@ 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 @@ -414,7 +488,7 @@ static char *read_body(FILE * fp) int c; size = 128; - text = smalloc(size); + text = snewn(size, char); len = 0; text[len] = '\0'; @@ -432,7 +506,7 @@ static char *read_body(FILE * fp) } if (len + 1 > size) { size += 128; - text = srealloc(text, size); + text = sresize(text, size, char); } text[len++] = c; text[len] = '\0'; @@ -487,7 +561,7 @@ int base64_decode_atom(char *atom, unsigned char *out) 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 +569,7 @@ 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 +605,8 @@ struct ssh2_userkey ssh2_wrong_passphrase = { NULL, NULL, NULL }; -struct ssh2_userkey *ssh2_load_userkey(char *filename, char *passphrase) +struct ssh2_userkey *ssh2_load_userkey(const Filename *filename, + char *passphrase, const char **errorstr) { FILE *fp; char header[40], *b, *encryption, *comment, *mac; @@ -542,14 +617,17 @@ 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"); + if (!fp) { + error = "can't open file"; goto error; + } /* Read the first header line which contains the key type. */ if (!read_header(fp, header)) @@ -560,8 +638,11 @@ 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 { + 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. */ @@ -683,7 +764,7 @@ 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); @@ -702,7 +783,7 @@ 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); @@ -725,7 +806,12 @@ 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) { + ret = SSH2_WRONG_PASSPHRASE; + } else { + error = "MAC failed"; + ret = NULL; + } goto error; } } @@ -734,7 +820,7 @@ struct ssh2_userkey *ssh2_load_userkey(char *filename, char *passphrase) /* * 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, @@ -743,10 +829,14 @@ struct ssh2_userkey *ssh2_load_userkey(char *filename, char *passphrase) sfree(ret->comment); sfree(ret); ret = NULL; + error = "createkey failed"; + goto error; } sfree(public_blob); sfree(private_blob); sfree(encryption); + if (errorstr) + *errorstr = NULL; return ret; /* @@ -765,11 +855,13 @@ struct ssh2_userkey *ssh2_load_userkey(char *filename, char *passphrase) sfree(public_blob); if (private_blob) sfree(private_blob); + if (errorstr) + *errorstr = error; return ret; } -char *ssh2_userkey_loadpub(char *filename, char **algorithm, - int *pub_blob_len) +char *ssh2_userkey_loadpub(const Filename *filename, char **algorithm, + int *pub_blob_len, const char **errorstr) { FILE *fp; char header[40], *b; @@ -777,18 +869,24 @@ char *ssh2_userkey_loadpub(char *filename, char **algorithm, unsigned char *public_blob; int public_blob_len; int i; + const char *error = NULL; public_blob = NULL; - fp = fopen(filename, "rb"); - if (!fp) + fp = f_open(*filename, "rb"); + if (!fp) { + error = "can't open file"; 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"))) { + 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. */ @@ -827,9 +925,11 @@ char *ssh2_userkey_loadpub(char *filename, char **algorithm, goto error; fclose(fp); - *pub_blob_len = public_blob_len; - *algorithm = alg->name; - return public_blob; + if (pub_blob_len) + *pub_blob_len = public_blob_len; + if (algorithm) + *algorithm = alg->name; + return (char *)public_blob; /* * Error processing. @@ -839,10 +939,12 @@ char *ssh2_userkey_loadpub(char *filename, char **algorithm, fclose(fp); if (public_blob) sfree(public_blob); + if (errorstr) + *errorstr = error; 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 +953,7 @@ int ssh2_userkey_encrypted(char *filename, char **commentptr) if (commentptr) *commentptr = NULL; - fp = fopen(filename, "rb"); + fp = f_open(*filename, "rb"); if (!fp) return 0; if (!read_header(fp, header) @@ -905,52 +1007,30 @@ 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, 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; @@ -985,7 +1065,7 @@ 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 +1092,7 @@ 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); @@ -1034,7 +1114,7 @@ int ssh2_save_userkey(char *filename, struct ssh2_userkey *key, } if (passphrase) { - char key[40]; + unsigned char key[40]; SHA_State s; passlen = strlen(passphrase); @@ -1054,16 +1134,16 @@ int ssh2_save_userkey(char *filename, struct ssh2_userkey *key, memset(&s, 0, sizeof(s)); } - fp = fopen(filename, "w"); + fp = f_open(*filename, "w"); if (!fp) 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]); @@ -1078,22 +1158,51 @@ int ssh2_save_userkey(char *filename, struct ssh2_userkey *key, } /* ---------------------------------------------------------------------- - * A function to determine which version of SSH to try on a private - * key file. Returns 0 on failure, 1 or 2 on success. + * A function to determine the type of a private key file. Returns + * 0 on failure, 1 or 2 on success. */ -int keyfile_version(char *filename) +int key_type(const Filename *filename) { FILE *fp; + char buf[32]; + const char putty2_sig[] = "PuTTY-User-Key-File-"; + const char sshcom_sig[] = "---- BEGIN SSH2 ENCRYPTED PRIVAT"; + const char openssh_sig[] = "-----BEGIN "; int i; - fp = fopen(filename, "r"); + fp = f_open(*filename, "r"); if (!fp) - return 0; - i = fgetc(fp); + return SSH_KEYTYPE_UNOPENABLE; + i = fread(buf, 1, sizeof(buf), 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 */ + if (i < 0) + return SSH_KEYTYPE_UNOPENABLE; + if (i < 32) + return SSH_KEYTYPE_UNKNOWN; + if (!memcmp(buf, rsa_signature, sizeof(rsa_signature)-1)) + return SSH_KEYTYPE_SSH1; + if (!memcmp(buf, putty2_sig, sizeof(putty2_sig)-1)) + return SSH_KEYTYPE_SSH2; + if (!memcmp(buf, openssh_sig, sizeof(openssh_sig)-1)) + return SSH_KEYTYPE_OPENSSH; + if (!memcmp(buf, sshcom_sig, sizeof(sshcom_sig)-1)) + return SSH_KEYTYPE_SSHCOM; + return SSH_KEYTYPE_UNKNOWN; /* unrecognised or EOF */ +} + +/* + * Convert the type word to a string, for `wrong type' error + * messages. + */ +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 private key"; break; + case SSH_KEYTYPE_SSH1: return "SSH1 private key"; break; + case SSH_KEYTYPE_SSH2: return "PuTTY SSH2 private key"; break; + case SSH_KEYTYPE_OPENSSH: return "OpenSSH SSH2 private key"; break; + case SSH_KEYTYPE_SSHCOM: return "ssh.com SSH2 private key"; break; + default: return "INTERNAL ERROR"; break; + } }