Mercurial > dropbear
view signkey.c @ 1036:deed0571cacc
DROPBEAR_ prefix for include guards to avoid collisions
author | Thorsten Horstmann <thorsten.horstmann@web.de> |
---|---|
date | Tue, 24 Feb 2015 20:43:01 +0800 |
parents | 25692c60479e |
children | 0da8ba489c23 |
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/* * Dropbear - a SSH2 server * * Copyright (c) 2002,2003 Matt Johnston * All rights reserved. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ #include "includes.h" #include "dbutil.h" #include "signkey.h" #include "buffer.h" #include "ssh.h" #include "ecdsa.h" static const char *signkey_names[DROPBEAR_SIGNKEY_NUM_NAMED] = { #ifdef DROPBEAR_RSA "ssh-rsa", #endif #ifdef DROPBEAR_DSS "ssh-dss", #endif #ifdef DROPBEAR_ECDSA "ecdsa-sha2-nistp256", "ecdsa-sha2-nistp384", "ecdsa-sha2-nistp521" #endif /* DROPBEAR_ECDSA */ }; /* malloc a new sign_key and set the dss and rsa keys to NULL */ sign_key * new_sign_key() { sign_key * ret; ret = (sign_key*)m_malloc(sizeof(sign_key)); ret->type = DROPBEAR_SIGNKEY_NONE; ret->source = SIGNKEY_SOURCE_INVALID; return ret; } /* Returns key name corresponding to the type. Exits fatally * if the type is invalid */ const char* signkey_name_from_type(enum signkey_type type, unsigned int *namelen) { if (type >= DROPBEAR_SIGNKEY_NUM_NAMED) { dropbear_exit("Bad key type %d", type); } if (namelen) { *namelen = strlen(signkey_names[type]); } return signkey_names[type]; } /* Returns DROPBEAR_SIGNKEY_NONE if none match */ enum signkey_type signkey_type_from_name(const char* name, unsigned int namelen) { int i; for (i = 0; i < DROPBEAR_SIGNKEY_NUM_NAMED; i++) { const char *fixed_name = signkey_names[i]; if (namelen == strlen(fixed_name) && memcmp(fixed_name, name, namelen) == 0) { #ifdef DROPBEAR_ECDSA /* Some of the ECDSA key sizes are defined even if they're not compiled in */ if (0 #ifndef DROPBEAR_ECC_256 || i == DROPBEAR_SIGNKEY_ECDSA_NISTP256 #endif #ifndef DROPBEAR_ECC_384 || i == DROPBEAR_SIGNKEY_ECDSA_NISTP384 #endif #ifndef DROPBEAR_ECC_521 || i == DROPBEAR_SIGNKEY_ECDSA_NISTP521 #endif ) { TRACE(("attempt to use ecdsa type %d not compiled in", i)) return DROPBEAR_SIGNKEY_NONE; } #endif return i; } } TRACE(("signkey_type_from_name unexpected key type.")) return DROPBEAR_SIGNKEY_NONE; } /* Returns a pointer to the key part specific to "type" */ void ** signkey_key_ptr(sign_key *key, enum signkey_type type) { switch (type) { #ifdef DROPBEAR_ECDSA #ifdef DROPBEAR_ECC_256 case DROPBEAR_SIGNKEY_ECDSA_NISTP256: return (void**)&key->ecckey256; #endif #ifdef DROPBEAR_ECC_384 case DROPBEAR_SIGNKEY_ECDSA_NISTP384: return (void**)&key->ecckey384; #endif #ifdef DROPBEAR_ECC_521 case DROPBEAR_SIGNKEY_ECDSA_NISTP521: return (void**)&key->ecckey521; #endif #endif /* DROPBEAR_ECDSA */ #ifdef DROPBEAR_RSA case DROPBEAR_SIGNKEY_RSA: return (void**)&key->rsakey; #endif #ifdef DROPBEAR_DSS case DROPBEAR_SIGNKEY_DSS: return (void**)&key->dsskey; #endif default: return NULL; } } /* returns DROPBEAR_SUCCESS on success, DROPBEAR_FAILURE on fail. * type should be set by the caller to specify the type to read, and * on return is set to the type read (useful when type = _ANY) */ int buf_get_pub_key(buffer *buf, sign_key *key, enum signkey_type *type) { unsigned char* ident; unsigned int len; int keytype; int ret = DROPBEAR_FAILURE; TRACE2(("enter buf_get_pub_key")) ident = buf_getstring(buf, &len); keytype = signkey_type_from_name(ident, len); m_free(ident); if (*type != DROPBEAR_SIGNKEY_ANY && *type != keytype) { TRACE(("buf_get_pub_key bad type - got %d, expected %d", keytype, *type)) return DROPBEAR_FAILURE; } TRACE2(("buf_get_pub_key keytype is %d", keytype)) *type = keytype; /* Rewind the buffer back before "ssh-rsa" etc */ buf_incrpos(buf, -len - 4); #ifdef DROPBEAR_DSS if (keytype == DROPBEAR_SIGNKEY_DSS) { dss_key_free(key->dsskey); key->dsskey = m_malloc(sizeof(*key->dsskey)); ret = buf_get_dss_pub_key(buf, key->dsskey); if (ret == DROPBEAR_FAILURE) { m_free(key->dsskey); } } #endif #ifdef DROPBEAR_RSA if (keytype == DROPBEAR_SIGNKEY_RSA) { rsa_key_free(key->rsakey); key->rsakey = m_malloc(sizeof(*key->rsakey)); ret = buf_get_rsa_pub_key(buf, key->rsakey); if (ret == DROPBEAR_FAILURE) { m_free(key->rsakey); } } #endif #ifdef DROPBEAR_ECDSA if (signkey_is_ecdsa(keytype)) { ecc_key **eck = (ecc_key**)signkey_key_ptr(key, keytype); if (eck) { if (*eck) { ecc_free(*eck); *eck = NULL; } *eck = buf_get_ecdsa_pub_key(buf); if (*eck) { ret = DROPBEAR_SUCCESS; } } } #endif TRACE2(("leave buf_get_pub_key")) return ret; } /* returns DROPBEAR_SUCCESS on success, DROPBEAR_FAILURE on fail. * type should be set by the caller to specify the type to read, and * on return is set to the type read (useful when type = _ANY) */ int buf_get_priv_key(buffer *buf, sign_key *key, enum signkey_type *type) { unsigned char* ident; unsigned int len; int keytype; int ret = DROPBEAR_FAILURE; TRACE2(("enter buf_get_priv_key")) ident = buf_getstring(buf, &len); keytype = signkey_type_from_name(ident, len); m_free(ident); if (*type != DROPBEAR_SIGNKEY_ANY && *type != keytype) { TRACE(("wrong key type: %d %d", *type, keytype)) return DROPBEAR_FAILURE; } *type = keytype; /* Rewind the buffer back before "ssh-rsa" etc */ buf_incrpos(buf, -len - 4); #ifdef DROPBEAR_DSS if (keytype == DROPBEAR_SIGNKEY_DSS) { dss_key_free(key->dsskey); key->dsskey = m_malloc(sizeof(*key->dsskey)); ret = buf_get_dss_priv_key(buf, key->dsskey); if (ret == DROPBEAR_FAILURE) { m_free(key->dsskey); } } #endif #ifdef DROPBEAR_RSA if (keytype == DROPBEAR_SIGNKEY_RSA) { rsa_key_free(key->rsakey); key->rsakey = m_malloc(sizeof(*key->rsakey)); ret = buf_get_rsa_priv_key(buf, key->rsakey); if (ret == DROPBEAR_FAILURE) { m_free(key->rsakey); } } #endif #ifdef DROPBEAR_ECDSA if (signkey_is_ecdsa(keytype)) { ecc_key **eck = (ecc_key**)signkey_key_ptr(key, keytype); if (eck) { if (*eck) { ecc_free(*eck); *eck = NULL; } *eck = buf_get_ecdsa_priv_key(buf); if (*eck) { ret = DROPBEAR_SUCCESS; } } } #endif TRACE2(("leave buf_get_priv_key")) return ret; } /* type is either DROPBEAR_SIGNKEY_DSS or DROPBEAR_SIGNKEY_RSA */ void buf_put_pub_key(buffer* buf, sign_key *key, enum signkey_type type) { buffer *pubkeys; TRACE2(("enter buf_put_pub_key")) pubkeys = buf_new(MAX_PUBKEY_SIZE); #ifdef DROPBEAR_DSS if (type == DROPBEAR_SIGNKEY_DSS) { buf_put_dss_pub_key(pubkeys, key->dsskey); } #endif #ifdef DROPBEAR_RSA if (type == DROPBEAR_SIGNKEY_RSA) { buf_put_rsa_pub_key(pubkeys, key->rsakey); } #endif #ifdef DROPBEAR_ECDSA if (signkey_is_ecdsa(type)) { ecc_key **eck = (ecc_key**)signkey_key_ptr(key, type); if (eck) { buf_put_ecdsa_pub_key(pubkeys, *eck); } } #endif if (pubkeys->len == 0) { dropbear_exit("Bad key types in buf_put_pub_key"); } buf_putbufstring(buf, pubkeys); buf_free(pubkeys); TRACE2(("leave buf_put_pub_key")) } /* type is either DROPBEAR_SIGNKEY_DSS or DROPBEAR_SIGNKEY_RSA */ void buf_put_priv_key(buffer* buf, sign_key *key, enum signkey_type type) { TRACE(("enter buf_put_priv_key")) TRACE(("type is %d", type)) #ifdef DROPBEAR_DSS if (type == DROPBEAR_SIGNKEY_DSS) { buf_put_dss_priv_key(buf, key->dsskey); TRACE(("leave buf_put_priv_key: dss done")) return; } #endif #ifdef DROPBEAR_RSA if (type == DROPBEAR_SIGNKEY_RSA) { buf_put_rsa_priv_key(buf, key->rsakey); TRACE(("leave buf_put_priv_key: rsa done")) return; } #endif #ifdef DROPBEAR_ECDSA if (signkey_is_ecdsa(type)) { ecc_key **eck = (ecc_key**)signkey_key_ptr(key, type); if (eck) { buf_put_ecdsa_priv_key(buf, *eck); TRACE(("leave buf_put_priv_key: ecdsa done")) return; } } #endif dropbear_exit("Bad key types in put pub key"); } void sign_key_free(sign_key *key) { TRACE2(("enter sign_key_free")) #ifdef DROPBEAR_DSS dss_key_free(key->dsskey); key->dsskey = NULL; #endif #ifdef DROPBEAR_RSA rsa_key_free(key->rsakey); key->rsakey = NULL; #endif #ifdef DROPBEAR_ECDSA #ifdef DROPBEAR_ECC_256 if (key->ecckey256) { ecc_free(key->ecckey256); key->ecckey256 = NULL; } #endif #ifdef DROPBEAR_ECC_384 if (key->ecckey384) { ecc_free(key->ecckey384); key->ecckey384 = NULL; } #endif #ifdef DROPBEAR_ECC_521 if (key->ecckey521) { ecc_free(key->ecckey521); key->ecckey521 = NULL; } #endif #endif m_free(key->filename); m_free(key); TRACE2(("leave sign_key_free")) } static char hexdig(unsigned char x) { if (x > 0xf) return 'X'; if (x < 10) return '0' + x; else return 'a' + x - 10; } /* Since we're not sure if we'll have md5 or sha1, we present both. * MD5 is used in preference, but sha1 could still be useful */ #ifdef DROPBEAR_MD5_HMAC static char * sign_key_md5_fingerprint(unsigned char* keyblob, unsigned int keybloblen) { char * ret; hash_state hs; unsigned char hash[MD5_HASH_SIZE]; unsigned int i; unsigned int buflen; md5_init(&hs); /* skip the size int of the string - this is a bit messy */ md5_process(&hs, keyblob, keybloblen); md5_done(&hs, hash); /* "md5 hexfingerprinthere\0", each hex digit is "AB:" etc */ buflen = 4 + 3*MD5_HASH_SIZE; ret = (char*)m_malloc(buflen); memset(ret, 'Z', buflen); strcpy(ret, "md5 "); for (i = 0; i < MD5_HASH_SIZE; i++) { unsigned int pos = 4 + i*3; ret[pos] = hexdig(hash[i] >> 4); ret[pos+1] = hexdig(hash[i] & 0x0f); ret[pos+2] = ':'; } ret[buflen-1] = 0x0; return ret; } #else /* use SHA1 rather than MD5 for fingerprint */ static char * sign_key_sha1_fingerprint(unsigned char* keyblob, unsigned int keybloblen) { char * ret; hash_state hs; unsigned char hash[SHA1_HASH_SIZE]; unsigned int i; unsigned int buflen; sha1_init(&hs); /* skip the size int of the string - this is a bit messy */ sha1_process(&hs, keyblob, keybloblen); sha1_done(&hs, hash); /* "sha1!! hexfingerprinthere\0", each hex digit is "AB:" etc */ buflen = 7 + 3*SHA1_HASH_SIZE; ret = (char*)m_malloc(buflen); strcpy(ret, "sha1!! "); for (i = 0; i < SHA1_HASH_SIZE; i++) { unsigned int pos = 7 + 3*i; ret[pos] = hexdig(hash[i] >> 4); ret[pos+1] = hexdig(hash[i] & 0x0f); ret[pos+2] = ':'; } ret[buflen-1] = 0x0; return ret; } #endif /* MD5/SHA1 switch */ /* This will return a freshly malloced string, containing a fingerprint * in either sha1 or md5 */ char * sign_key_fingerprint(unsigned char* keyblob, unsigned int keybloblen) { #ifdef DROPBEAR_MD5_HMAC return sign_key_md5_fingerprint(keyblob, keybloblen); #else return sign_key_sha1_fingerprint(keyblob, keybloblen); #endif } void buf_put_sign(buffer* buf, sign_key *key, enum signkey_type type, buffer *data_buf) { buffer *sigblob; sigblob = buf_new(MAX_PUBKEY_SIZE); #ifdef DROPBEAR_DSS if (type == DROPBEAR_SIGNKEY_DSS) { buf_put_dss_sign(sigblob, key->dsskey, data_buf); } #endif #ifdef DROPBEAR_RSA if (type == DROPBEAR_SIGNKEY_RSA) { buf_put_rsa_sign(sigblob, key->rsakey, data_buf); } #endif #ifdef DROPBEAR_ECDSA if (signkey_is_ecdsa(type)) { ecc_key **eck = (ecc_key**)signkey_key_ptr(key, type); if (eck) { buf_put_ecdsa_sign(sigblob, *eck, data_buf); } } #endif if (sigblob->len == 0) { dropbear_exit("Non-matching signing type"); } buf_putbufstring(buf, sigblob); buf_free(sigblob); } #ifdef DROPBEAR_SIGNKEY_VERIFY /* Return DROPBEAR_SUCCESS or DROPBEAR_FAILURE. * If FAILURE is returned, the position of * buf is undefined. If SUCCESS is returned, buf will be positioned after the * signature blob */ int buf_verify(buffer * buf, sign_key *key, buffer *data_buf) { unsigned char * type_name = NULL; unsigned int type_name_len = 0; enum signkey_type type; TRACE(("enter buf_verify")) buf_getint(buf); /* blob length */ type_name = buf_getstring(buf, &type_name_len); type = signkey_type_from_name(type_name, type_name_len); m_free(type_name); #ifdef DROPBEAR_DSS if (type == DROPBEAR_SIGNKEY_DSS) { if (key->dsskey == NULL) { dropbear_exit("No DSS key to verify signature"); } return buf_dss_verify(buf, key->dsskey, data_buf); } #endif #ifdef DROPBEAR_RSA if (type == DROPBEAR_SIGNKEY_RSA) { if (key->rsakey == NULL) { dropbear_exit("No RSA key to verify signature"); } return buf_rsa_verify(buf, key->rsakey, data_buf); } #endif #ifdef DROPBEAR_ECDSA if (signkey_is_ecdsa(type)) { ecc_key **eck = (ecc_key**)signkey_key_ptr(key, type); if (eck) { return buf_ecdsa_verify(buf, *eck, data_buf); } } #endif dropbear_exit("Non-matching signing type"); return DROPBEAR_FAILURE; } #endif /* DROPBEAR_SIGNKEY_VERIFY */ #ifdef DROPBEAR_KEY_LINES /* ie we're using authorized_keys or known_hosts */ /* Returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE when given a buffer containing * a key, a key, and a type. The buffer is positioned at the start of the * base64 data, and contains no trailing data */ /* If fingerprint is non-NULL, it will be set to a malloc()ed fingerprint of the key if it is successfully decoded */ int cmp_base64_key(const unsigned char* keyblob, unsigned int keybloblen, const unsigned char* algoname, unsigned int algolen, buffer * line, char ** fingerprint) { buffer * decodekey = NULL; int ret = DROPBEAR_FAILURE; unsigned int len, filealgolen; unsigned long decodekeylen; unsigned char* filealgo = NULL; /* now we have the actual data */ len = line->len - line->pos; decodekeylen = len * 2; /* big to be safe */ decodekey = buf_new(decodekeylen); if (base64_decode(buf_getptr(line, len), len, buf_getwriteptr(decodekey, decodekey->size), &decodekeylen) != CRYPT_OK) { TRACE(("checkpubkey: base64 decode failed")) goto out; } TRACE(("checkpubkey: base64_decode success")) buf_incrlen(decodekey, decodekeylen); if (fingerprint) { *fingerprint = sign_key_fingerprint(buf_getptr(decodekey, decodekeylen), decodekeylen); } /* compare the keys */ if ( ( decodekeylen != keybloblen ) || memcmp( buf_getptr(decodekey, decodekey->len), keyblob, decodekey->len) != 0) { TRACE(("checkpubkey: compare failed")) goto out; } /* ... and also check that the algo specified and the algo in the key * itself match */ filealgolen = buf_getint(decodekey); filealgo = buf_getptr(decodekey, filealgolen); if (filealgolen != algolen || memcmp(filealgo, algoname, algolen) != 0) { TRACE(("checkpubkey: algo match failed")) goto out; } /* All checks passed */ ret = DROPBEAR_SUCCESS; out: buf_free(decodekey); decodekey = NULL; return ret; } #endif