From: Guus Sliepen Date: Sat, 24 Jan 2009 15:38:40 +0000 (+0100) Subject: Autoconfiscation. X-Git-Url: https://www.tinc-vpn.org/git/?a=commitdiff_plain;h=811b273f857703f489875376f188f1fc21b7e850;p=fides Autoconfiscation. --- diff --git a/Makefile b/Makefile deleted file mode 100644 index a7a4bd6..0000000 --- a/Makefile +++ /dev/null @@ -1,13 +0,0 @@ -all: fides - -CFLAGS ?= -Wall -g -O0 -LDFLAGS ?= -Wall -g -O0 - -fides: fides.o - $(CXX) $(LDFLAGS) -o $@ $< -lbotan - -%.o: %.cc %.h - $(CXX) $(CFLAGS) -g -c -Wall -o $@ $< - -clean: - rm -f *.o fides diff --git a/Makefile.am b/Makefile.am new file mode 100644 index 0000000..1e0060f --- /dev/null +++ b/Makefile.am @@ -0,0 +1,6 @@ +AUTOMAKE_OPTIONS = foreign + +SUBDIRS = lib src + +ChangeLog: + git log > ChangeLog diff --git a/configure.ac b/configure.ac new file mode 100644 index 0000000..415538b --- /dev/null +++ b/configure.ac @@ -0,0 +1,21 @@ +AC_INIT +AM_INIT_AUTOMAKE([fides], [0.1]) +AC_PREREQ(2.61) +AC_COPYRIGHT([Copyright (c) 2008-2009 Guus Sliepen ]) +AC_REVISION($Revision$) +AC_CONFIG_SRCDIR(src/fides.cc) + +AC_GNU_SOURCE + +AC_PROG_CXX +AC_PROG_CXXCPP +AC_PROG_INSTALL +AC_PROG_MAKE_SET +AC_PROG_LIBTOOL + +PKG_CHECK_MODULES(BOTAN, botan-1.8 >= 1.8.0) +AC_SUBST(BOTAN_CFLAGS) +AC_SUBST(BOTAN_LIBS) + +AC_CONFIG_FILES([Makefile lib/Makefile src/Makefile]) +AC_OUTPUT diff --git a/fides.cc b/fides.cc deleted file mode 100644 index eb2de1a..0000000 --- a/fides.cc +++ /dev/null @@ -1,1118 +0,0 @@ -/* fides.c - Light-weight, decentralised trust and authorisation management - Copyright (C) 2008-2009 Guus Sliepen - - Fides is free software; you can redistribute it and/or modify - it under the terms of the GNU Lesser General Public License as - published by the Free Software Foundation; either version 2.1 of - the License, or (at your option) any later version. - - Fides is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with this program; if not, see . -*/ - -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#include "fides.h" - -using namespace std; - -// Global state - -Botan::LibraryInitializer libinit; -Botan::AutoSeeded_RNG fides::rng; - -// Public key functions - -fides::publickey::publickey(): pub(0), trust(0) { -} - -fides::publickey::~publickey() { - delete pub; -} - -void fides::publickey::load(istream &in) { - try { - Botan::DataSource_Stream source(in); - pub = dynamic_cast(Botan::X509::load_key(source)); - } catch(Botan::Exception &e) { - throw exception(e.what()); - } -} - -void fides::publickey::load(const std::string &filename) { - ifstream in(filename.c_str()); - load(in); -} - -void fides::publickey::save(ostream &out) { - out << to_string(); -} - -void fides::publickey::save(const std::string &filename) { - ofstream out(filename.c_str()); - save(out); -} - -void fides::publickey::from_string(const std::string &in) { - try { - Botan::DataSource_Memory source(in); - pub = dynamic_cast(Botan::X509::load_key(source)); - } catch(Botan::Exception &e) { - throw exception(e.what()); - } -} - -string fides::publickey::to_string() { - return Botan::X509::PEM_encode(*pub); -} - -string fides::publickey::fingerprint(unsigned int bits) { - // TODO: find out if there is a standard way to get a hash of an ECDSA public key - Botan::SHA_256 sha256; - Botan::SecureVector hash = sha256.process(Botan::X509::PEM_encode(*pub)); - return string((const char *)hash.begin(), bits / 8); -} - -bool fides::publickey::verify(const std::string &statement, const std::string &signature) { - auto_ptr verifier(Botan::get_pk_verifier(*pub, "EMSA1(SHA-512)")); - verifier->update((const Botan::byte *)statement.data(), statement.size()); - Botan::SecureVector sig; - sig.set((const Botan::byte *)signature.data(), signature.size()); - return verifier->check_signature(sig); -} - -// Private key functions - -fides::privatekey::privatekey(): priv(0) { -} - -fides::privatekey::~privatekey() { - delete priv; - pub = 0; -} - -void fides::privatekey::generate(const std::string &field) { - Botan::EC_Domain_Params domain = Botan::get_EC_Dom_Pars_by_oid(field); - pub = priv = new Botan::ECDSA_PrivateKey(rng, domain); -} - -void fides::privatekey::generate(unsigned int bits) { - switch(bits) { - case 112: return generate("1.3.132.0.6"); - case 128: return generate("1.3.132.0.28"); - case 160: return generate("1.3.132.0.9"); - case 192: return generate("1.3.132.0.31"); - case 224: return generate("1.3.132.0.32"); - case 256: return generate("1.3.132.0.10"); - case 384: return generate("1.3.132.0.34"); - case 521: return generate("1.3.132.0.35"); - default: throw exception("Unsupported number of bits for private key"); - } -} - -void fides::privatekey::load_private(istream &in) { - try { - Botan::DataSource_Stream stream(in); - pub = priv = dynamic_cast(Botan::PKCS8::load_key(stream, rng, "")); - } catch(Botan::Exception &e) { - throw exception(e.what()); - } -} - -void fides::privatekey::load_private(const std::string &filename) { - ifstream in(filename.c_str()); - load_private(in); -} - -void fides::privatekey::save_private(ostream &out) { - out << Botan::PKCS8::PEM_encode(*priv); -} - -void fides::privatekey::save_private(const std::string &filename) { - ofstream out(filename.c_str()); - save_private(out); -} - -string fides::privatekey::sign(const std::string &statement) { - auto_ptr signer(Botan::get_pk_signer(*priv, "EMSA1(SHA-512)")); - Botan::SecureVector sig = signer->sign_message((const Botan::byte *)statement.data(), statement.size(), rng); - return string((const char *)sig.begin(), (size_t)sig.size()); -} - -// Base64 and hex encoding/decoding functions - -string fides::hexencode(const string &in) { - Botan::Pipe pipe(new Botan::Hex_Encoder); - pipe.process_msg((Botan::byte *)in.data(), in.size()); - return pipe.read_all_as_string(); -} - -string fides::hexdecode(const string &in) { - Botan::Pipe pipe(new Botan::Hex_Decoder); - pipe.process_msg((Botan::byte *)in.data(), in.size()); - return pipe.read_all_as_string(); -} - -string fides::b64encode(const string &in) { - Botan::Pipe pipe(new Botan::Base64_Encoder); - pipe.process_msg((Botan::byte *)in.data(), in.size()); - return pipe.read_all_as_string(); -} - -string fides::b64decode(const string &in) { - Botan::Pipe pipe(new Botan::Base64_Decoder); - pipe.process_msg((Botan::byte *)in.data(), in.size()); - return pipe.read_all_as_string(); -} - -// Certificate functions - -fides::certificate::certificate(publickey *key, struct timeval timestamp, const std::string &statement, const std::string &signature): signer(key), timestamp(timestamp), statement(statement), signature(signature) {} - -bool fides::certificate::validate() { - string data = signer->fingerprint(256); - data += string((const char *)×tamp, sizeof timestamp); - data += statement; - return signer->verify(data, signature); -} - -fides::certificate::certificate(privatekey *key, struct timeval timestamp, const std::string &statement): signer(key), timestamp(timestamp), statement(statement) { - string data = signer->fingerprint(256); - data += string((const char *)×tamp, sizeof timestamp); - data += statement; - signature = key->sign(data); -} - -string fides::certificate::fingerprint(unsigned int bits) { - return signature.substr(signature.size() - bits / 8); -} - -string fides::certificate::to_string() const { - string data = fides::hexencode(signer->fingerprint()); - data += ' '; - char ts[100]; - snprintf(ts, sizeof ts, "%lu.%06lu", timestamp.tv_sec, timestamp.tv_usec); - data += ts; - data += ' '; - data += fides::b64encode(signature); - data += ' '; - data += statement; - return data; -} - -static void help(ostream &out, const string &argv0) { - out << "Usage: " << argv0 << " [arguments]\n" - "\n" - "Available commands are:\n" - "\n" - " init Initialise fides, generate a public/private keypair.\n" - " version Show version and copyright information.\n" - " help Show this help message.\n" - "\n" - " trust \n" - " Trust allow/deny packets signed by the specified key.\n" - " distrust \n" - " Distrust allow/deny packets signed by the specified key.\n" - " dctrust \n" - " Don't care about allow/deny packets signed by the specified key.\n" - " is_trusted \n" - " Returns 0 if key is trusted, 1 otherwise\n" - " is_distrusted \n" - " Returns 0 if key is distrusted, 1 otherwise\n" - "\n" - " sign \n" - " Sign stuff.\n" - " allow \n" - " Allow stuff.\n" - " deny \n" - " Deny stuff.\n" - " dontcare \n" - " Don't care about stuff.\n" - " is_allowed \n" - " Returns 0 if stuff is allowed, 1 otherwise\n" - " is_denied \n" - " Returns 0 if stuff is denied, 1 otherwise\n" - "\n" - " import [filename]\n" - " Import keys and certificates from file, or stdin if unspecified.\n" - " export [filename]\n" - " Export keys and certificates to file, or stdout if unspecified.\n" - " test \n" - " Tell whether stuff is allowed or not by counting relevant certificates\n" - " find \n" - " Find all certificates matching regexp\n" - " fsck Verify the signature on all information collected.\n"; -} - -static void version(ostream &out = cout) { - out << "fides version 0.1\n" - "Copyright (c) 2008-2009 Guus Sliepen \n" - "\n" - "This program is free software; you can redistribute it and/or modify\n" - "it under the terms of the GNU General Public License as published by\n" - "the Free Software Foundation; either version 2 of the License, or\n" - "(at your option) any later version.\n"; -} - -// Utility functions - -static vector dirlist(const string &path) { - vector files; - - DIR *dir = opendir(path.c_str()); - if(!dir) - return files; - - struct dirent entry, *result = &entry; - - while(result) { - readdir_r(dir, &entry, &result); - if(!result) - break; - struct stat st; - if(result->d_type == DT_UNKNOWN) { - if(stat((path + "/" + result->d_name).c_str(), &st)) - continue; - if(S_ISREG(st.st_mode)) - files.push_back(result->d_name); - } else if(result->d_type == DT_REG) { - files.push_back(result->d_name); - } - } - - closedir(dir); - - return files; -} - -void fides::certificate_save(const certificate *cert, const string &filename) { - ofstream file(filename.c_str()); - file << cert->to_string() << '\n'; -} - -fides::certificate *fides::certificate_load(const string &filename) { - ifstream file(filename.c_str()); - string data; - getline(file, data); - return certificate_from_string(data); -} - -fides::certificate *fides::certificate_from_string(const string &data) { - size_t b, e; - e = data.find(' ', 0); - if(e == string::npos) - throw exception("Invalid certificate"); - string fingerprint = hexdecode(data.substr(0, e)); - publickey *signer = find_key(fingerprint); - if(!signer) - throw exception("Unknown public key"); - b = e + 1; - e = data.find('.', b); - if(e == string::npos) - throw exception("Invalid certificate"); - struct timeval timestamp; - timestamp.tv_sec = atol(data.c_str() + b); - b = e + 1; - timestamp.tv_usec = atol(data.c_str() + b); - e = data.find(' ', b); - if(e == string::npos) - throw exception("Invalid certificate"); - b = e + 1; - e = data.find(' ', b); - if(e == string::npos) - throw exception("Invalid certificate"); - string signature = fides::b64decode(data.substr(b, e - b)); - b = e + 1; - string statement = data.substr(b); - - return new certificate(signer, timestamp, statement, signature); -} - -// Fides main functions - -fides::fides(const string &dir): homedir(dir) { - cerr << "Fides initialising\n"; - - // Set homedir to provided directory, or $FIDES_HOME, or $HOME/.fides, or as a last resort $PWD/.fides - if(homedir.empty()) - homedir = getenv("FIDES_HOME") ?: ""; - if(homedir.empty()) { - char cwd[PATH_MAX]; - homedir = getenv("HOME") ?: getcwd(cwd, sizeof cwd); - homedir += "/.fides"; - } - - // Derived directories - homedir += '/'; - certdir = homedir + "certs/"; - keydir = homedir + "keys/"; - obsoletedir = homedir + ".obsolete_certs/"; - - // Ensure the homedir and its subdirectories exist - mkdir(homedir.c_str(), 0700); - mkdir(certdir.c_str(), 0700); - mkdir(keydir.c_str(), 0700); - mkdir(obsoletedir.c_str(), 0700); - - try { - mykey.load_private(homedir + "priv"); - firstrun = false; - } catch(fides::exception &e) { - cerr << "Fides generating keypair\n"; - mykey.generate(); - mykey.save_private(homedir + "priv"); - mykey.save(keydir + hexencode(mykey.fingerprint())); - firstrun = true; - } - vector files = dirlist(keydir); - for(size_t i = 0; i < files.size(); ++i) { - cerr << "Loading key " << files[i] << '\n'; - - publickey *key = new publickey(); - key->load(keydir + files[i]); - keys[hexdecode(files[i])] = key; - } - - keys[mykey.fingerprint()] = &mykey; - - files = dirlist(certdir); - for(size_t i = 0; i < files.size(); ++i) { - cerr << "Loading certificate " << files[i] << '\n'; - certificate *cert = certificate_load(certdir + files[i]); - if(false && !cert->validate()) { - cerr << "Bad certificate!\n"; - continue; - } - certs[hexdecode(files[i])] = cert; - } - - // TODO: save and load this value - latest.tv_sec = 0; - latest.tv_usec = 0; - - update_trust(); -} - -fides::~fides() { - cerr << "Fides exitting\n"; - for(map::iterator i = certs.begin(); i != certs.end(); ++i) - delete i->second; - for(map::iterator i = keys.begin(); i != keys.end(); ++i) - if(i->second != &mykey) - delete i->second; -} - -bool fides::fsck() { - int errors = 0; - - for(map::iterator i = certs.begin(); i != certs.end(); ++i) { - if(!i->second->validate()) { - cerr << "Validation of certificate failed: " << i->second->to_string() << '\n'; - errors++; - } - } - - cerr << errors << " errors in " << certs.size() << " certificates\n"; - return !errors; -} - -string fides::get_homedir() { - return homedir; -} - -bool fides::is_firstrun() { - return firstrun; -} - -fides::publickey *fides::find_key(const string &fingerprint) { - map::iterator i; - i = keys.find(fingerprint); - if(i != keys.end()) - return i->second; - else - return 0; -} - -vector fides::find_certificates(publickey *signer, const string ®ex) { - vector found; - map::iterator i; - regexp regexp(regex); - for(i = certs.begin(); i != certs.end(); ++i) { - if(!i->second) { - cerr << "No certificate for " << hexencode(i->first) << '\n'; - continue; - } - if(i->second->signer == signer) - if(regexp.match(i->second->statement)) - found.push_back(i->second); - } - return found; -} - -vector fides::find_certificates(const string ®ex) { - vector found; - map::iterator i; - regexp regexp(regex); - for(i = certs.begin(); i != certs.end(); ++i) - if(regexp.match(i->second->statement)) - found.push_back(i->second); - return found; -} - -vector fides::find_certificates(publickey *signer) { - vector found; - map::iterator i; - for(i = certs.begin(); i != certs.end(); ++i) - if(i->second->signer == signer) - found.push_back(i->second); - return found; -} - -void fides::import_all(istream &in) { - string line, pem; - bool is_pem = false; - - while(getline(in, line)) { - if(line.empty()) - continue; - - if(is_pem || !line.compare(0, 11, "-----BEGIN ")) { - pem += line + '\n'; - if(!line.compare(0, 9, "-----END ")) { - fides::publickey *key = new publickey(); - key->from_string(pem); - cerr << "Imported key " << hexencode(key->fingerprint()) << '\n'; - merge(key); - is_pem = false; - } else { - is_pem = true; - } - continue; - } - - fides::certificate *cert = certificate_from_string(line); - cerr << "Importing certificate " << hexencode(cert->fingerprint()) << '\n'; - merge(cert); - } -} - -void fides::export_all(ostream &out) { - for(map::iterator i = keys.begin(); i != keys.end(); ++i) - out << i->second->to_string(); - for(map::iterator i = certs.begin(); i != certs.end(); ++i) - out << i->second->to_string() << '\n'; -} - -static int init() { - fides fides; - if(fides.is_firstrun()) { - cout << "New keys generated in " << fides.get_homedir() << '\n'; - } else { - cout << "Fides already initialised\n"; - } - return 0; -} - -void fides::trust(publickey *key) { - string full = "t+ " + hexencode(key->fingerprint()); - sign(full); -} - -void fides::distrust(publickey *key) { - string full = "t- " + hexencode(key->fingerprint()); - sign(full); -} - -void fides::dctrust(publickey *key) { - string full = "t0 " + hexencode(key->fingerprint()); - sign(full); -} - -static int is_trusted(int argc, char *const argv[]) { - if(argc < 1) - return EX_USAGE; - - fides fides; - fides::publickey *key = fides.find_key(fides::hexdecode(argv[0])); - if(!key) { - cerr << "Unknown key!\n"; - return 1; - } - return fides.is_trusted(key) ? 0 : 1; -} - -static int is_distrusted(int argc, char *const argv[]) { - if(argc < 1) - return EX_USAGE; - - fides fides; - fides::publickey *key = fides.find_key(fides::hexdecode(argv[0])); - if(!key) { - cerr << "Unknown key!\n"; - return 1; - } - return fides.is_distrusted(key) ? 0 : 1; -} - -static int trust(int argc, char *const argv[]) { - if(argc < 1) - return EX_USAGE; - - fides fides; - fides::publickey *key = fides.find_key(fides::hexdecode(argv[0])); - if(key) - fides.trust(key); - else { - cerr << "Unknown key!\n"; - return -1; - } - return 0; -} - -static int dctrust(int argc, char *const argv[]) { - if(argc < 1) - return EX_USAGE; - - fides fides; - fides::publickey *key = fides.find_key(fides::hexdecode(argv[0])); - if(key) - fides.dctrust(key); - else { - cerr << "Unknown key!\n"; - return -1; - } - return 0; -} - -static int distrust(int argc, char *const argv[]) { - if(argc < 1) - return EX_USAGE; - - fides fides; - fides::publickey *key = fides.find_key(fides::hexdecode(argv[0])); - if(key) - fides.distrust(key); - else { - cerr << "Unknown key!\n"; - return -1; - } - return 0; -} - -void fides::update_trust() { - // clear trust on all keys - for(map::iterator i = keys.begin(); i != keys.end(); ++i) - i->second->trust = 0; - - // Start by checking all trust certificates from ourself. - // If another key is positively or negatively trusted, update its trust score - // and add it to the the list of new keys to check. - // Then add our own key to the list of already checked keys. - // Then check all the trust certificates of those on the tocheck list, etc. - // Already checked keys are never updated anymore (TODO: is that smart?) - // Certificates of keys with a zero or negative trust score are not processed. - - set checked; - set tocheck; - set newkeys; - set::iterator i; - - mykey.trust = 3; - tocheck.insert(&mykey); - - while(tocheck.size()) { - // add - checked.insert(tocheck.begin(), tocheck.end()); - newkeys.clear(); - - // loop over all keys whose certificates need to be checked - - for(i = tocheck.begin(); i != tocheck.end(); ++i) { - cerr << "Trust for key " << hexencode((*i)->fingerprint()) << " set to " << (*i)->trust << '\n'; - - // except if this key is not trusted - - if((*i)->trust <= 0) - continue; - - // find all non-zero trust certificates of this key - - vector matches = find_certificates(*i, "^t[+-] "); - - // update trust value of those keys - - for(size_t j = 0; j < matches.size(); j++) { - publickey *other = find_key(hexdecode(matches[j]->statement.substr(3))); - - if(!other) { - cerr << "Trust certificate for unknown key: " << matches[j]->to_string() << '\n'; - continue; - } - - // except for keys we already checked - - if(checked.find(other) != checked.end()) { - cerr << "Skipping trust certificate for already checked key: " << matches[j]->to_string() << '\n'; - continue; - } - - // update trust - - if(matches[j]->statement[1] == '+') - other->trust++; - else - other->trust--; - - newkeys.insert(other); - } - } - - tocheck = newkeys; - } -} - -void fides::merge(publickey *key) { - if(keys.find(key->fingerprint()) != keys.end()) { - cerr << "Key already known\n"; - return; - } - - keys[key->fingerprint()] = key; - key->save(keydir + hexencode(key->fingerprint())); -} - -void fides::merge(certificate *cert) { - // TODO: check if cert is already in database - // TODO: check if cert obsoletes other certs - - // If we already know this certificate, drop it. - if(certs.find(cert->fingerprint()) != certs.end()) { - cerr << "Certificate already known\n"; - return; - } - - // If the certificate does not validate, drop it. - if(!cert->validate()) { - // TODO: this should not happen, be wary of DoS attacks - cerr << "Certificate invalid\n"; - return; - } - - // TODO: move these regexps to the class? - regexp authexp("^a[+0-] "); - regexp trustexp("^t[+0-] "); - vector others; - - // Is this an authorisation cert? - if(authexp.match(cert->statement)) { - // Find certs identical except for the +/-/0 - // TODO: escape statement in regexp - others = find_certificates(cert->signer, string("^a[+0-] ") + cert->statement.substr(3) + '$'); - if(others.size()) { - if(timercmp(&others[0]->timestamp, &cert->timestamp, >)) { - cerr << "Certificate is overruled by a newer certificate\n"; - return; - } - if(timercmp(&others[0]->timestamp, &cert->timestamp, ==)) { - // TODO: this should not happen, be wary of DoS attacks - cerr << "Certificate has same timestamp as another timestamp!\n"; - return; - } - cerr << "Certificate overrules an older certificate!\n"; - // save new cert first - certificate_save(cert, certdir + hexencode(cert->fingerprint())); - certs[cert->fingerprint()] = cert; - - // delete old one - rename((certdir + hexencode(others[0]->fingerprint())).c_str(), (obsoletedir + hexencode(others[0]->fingerprint())).c_str()); - certs.erase(others[0]->fingerprint()); - delete others[0]; - return; - } - } - - // Is this a trust cert? - // TODO: it's just the same as above! - if(trustexp.match(cert->statement)) { - // Find certs identical except for the +/-/0 - // TODO: escape statement in regexp - others = find_certificates(cert->signer, string("^t[+0-] ") + cert->statement.substr(3) + '$'); - if(others.size()) { - if(timercmp(&others[0]->timestamp, &cert->timestamp, >)) { - cerr << "Certificate is overruled by a newer certificate\n"; - return; - } - if(timercmp(&others[0]->timestamp, &cert->timestamp, ==)) { - // TODO: this should not happen, be wary of DoS attacks - cerr << "Certificate has same timestamp as another timestamp!\n"; - return; - } - cerr << "Certificate overrules an older certificate!\n"; - // delete old one - rename((certdir + hexencode(others[0]->fingerprint())).c_str(), (obsoletedir + hexencode(others[0]->fingerprint())).c_str()); - certs.erase(others[0]->fingerprint()); - delete others[0]; - certs[cert->fingerprint()] = cert; - certificate_save(cert, certdir + hexencode(cert->fingerprint())); - return; - } - } - - // Did somebody sign the exact same statement twice? - // Could happen if there is a different, conflicting statement between this new and the corresponding old one. - others = find_certificates(cert->signer, string("^") + cert->statement + '$'); - if(others.size()) { - if(timercmp(&others[0]->timestamp, &cert->timestamp, >)) { - cerr << "Certificate is overruled by a newer certificate\n"; - return; - } - if(timercmp(&others[0]->timestamp, &cert->timestamp, ==)) { - // TODO: this should not happen, be wary of DoS attacks - cerr << "Certificate has same timestamp as another timestamp!\n"; - return; - } - cerr << "Certificate overrules an older certificate!\n"; - // delete old one - rename((certdir + hexencode(others[0]->fingerprint())).c_str(), (obsoletedir + hexencode(others[0]->fingerprint())).c_str()); - certs.erase(others[0]->fingerprint()); - delete others[0]; - certs[cert->fingerprint()] = cert; - certificate_save(cert, certdir + hexencode(cert->fingerprint())); - return; - } - - cerr << "Certificate is new\n"; - certs[cert->fingerprint()] = cert; - certificate_save(cert, certdir + hexencode(cert->fingerprint())); -} - -void fides::auth_stats(const string &statement, int &self, int &trusted, int &all) { - self = trusted = all = 0; - vector matches = find_certificates(string("^a[+0-] ") + statement + '$'); - for(size_t i = 0; i < matches.size(); ++i) { - char code = matches[i]->statement[1]; - int diff = 0; - if(code == '+') - diff = 1; - else if(code == '-') - diff = -1; - if(matches[i]->signer == &mykey) - self += diff; - if(matches[i]->signer->trust > 0) - trusted += diff; - all += diff; - } -} - -bool fides::is_trusted(publickey *key) { - return key->trust > 0; -} - -bool fides::is_distrusted(publickey *key) { - return key->trust < 0; -} - -bool fides::is_allowed(const string &statement, publickey *key) { - int self, trusted, all; - - if(key) - auth_stats(hexencode(key->fingerprint()) + " " + statement, self, trusted, all); - else - auth_stats(statement, self, trusted, all); - - if(self) - return self > 0; - else if(trusted) - return trusted > 0; - else - return false; -} - -bool fides::is_denied(const string &statement, publickey *key) { - int self, trusted, all; - - if(key) - auth_stats(hexencode(key->fingerprint()) + " " + statement, self, trusted, all); - else - auth_stats(statement, self, trusted, all); - - if(self) - return self < 0; - else if(trusted) - return trusted < 0; - else - return false; -} - -void fides::sign(const string &statement) { - // Try to set "latest" to now, but ensure monoticity - struct timeval now; - gettimeofday(&now, 0); - if(timercmp(&latest, &now, >=)) { - latest.tv_usec++; - if(latest.tv_usec >= 1000000) { - latest.tv_sec++; - latest.tv_usec -= 1000000; - } - } else { - latest = now; - } - - // Create a new certificate and merge it with our database - merge(new certificate(&mykey, latest, statement)); -} - -void fides::allow(const string &statement, publickey *key) { - string full = "a+ "; - if(key) - full += hexencode(key->fingerprint()) + ' '; - full += statement; - sign(full); -} - -void fides::dontcare(const string &statement, publickey *key) { - string full = "a0 "; - if(key) - full += hexencode(key->fingerprint()) + ' '; - full += statement; - sign(full); -} - -void fides::deny(const string &statement, publickey *key) { - string full = "a- "; - if(key) - full += hexencode(key->fingerprint()) + ' '; - full += statement; - sign(full); -} - -static int sign(int argc, char *const argv[]) { - if(argc < 1) - return EX_USAGE; - - fides fides; - fides.sign(argv[0]); - return 0; -} - -static int allow(int argc, char *const argv[]) { - if(argc < 1) - return EX_USAGE; - - fides fides; - fides.allow(argv[0]); - return 0; -} - -static int dontcare(int argc, char *const argv[]) { - if(argc < 1) - return EX_USAGE; - - fides fides; - fides.dontcare(argv[0]); - return 0; -} - -static int deny(int argc, char *const argv[]) { - if(argc < 1) - return EX_USAGE; - - fides fides; - fides.deny(argv[0]); - return 0; -} - -static int import(int argc, char *const argv[]) { - fides fides; - - if(argc) { - ifstream in(argv[0]); - fides.import_all(in); - } else - fides.import_all(cin); - return 0; -} - -static int exprt(int argc, char *const argv[]) { - fides fides; - - if(argc) { - ofstream out(argv[0]); - fides.export_all(out); - } else - fides.export_all(cout); - return 0; -} - -static int find(int argc, char *const argv[]) { - if(argc < 1) - return EX_USAGE; - - // Find certificates matching statement - fides fides; - const vector &certs = fides.find_certificates(argv[0]); - for(size_t i = 0; i < certs.size(); ++i) - cout << i << ' ' << certs[i]->to_string() << '\n'; - return 0; -} - -static int is_allowed(int argc, char *const argv[]) { - if(argc < 1) - return EX_USAGE; - - fides fides; - return fides.is_allowed(argv[0]) ? 0 : 1; -} - -static int is_denied(int argc, char *const argv[]) { - if(argc < 1) - return EX_USAGE; - - fides fides; - return fides.is_denied(argv[0]) ? 0 : 1; -} - -static int test(int argc, char *const argv[]) { - if(argc < 1) - return EX_USAGE; - - fides fides; - int self, trusted, all; - fides.auth_stats(argv[0], self, trusted, all); - cout << "Self: " << self << ", trusted: " << trusted << ", all: " << all << '\n'; - return 0; -} - -static int fsck() { - fides fides; - if(fides.fsck()) { - cout << "Everything OK\n"; - return 0; - } else { - cout << "Integrity failure!\n"; - return 1; - } -} - -int main(int argc, char *const argv[]) { - int r; - int option_index; - - static struct option const long_options[] = { - {"homedir", required_argument, NULL, 2}, - {"help", no_argument, NULL, 'h'}, - {"version", no_argument, NULL, 3}, - {NULL, 0, NULL, 0} - }; - - while((r = getopt_long(argc, argv, "h", long_options, &option_index)) != EOF) { - switch (r) { - case 0: /* long option */ - break; - case 1: /* non-option */ - break; - case 2: - //homedir = strdup(optarg); - break; - case 3: - version(); - return 0; - case 'h': - help(cout, argv[0]); - return 0; - } - } - - if(argc < 2) { - help(cerr, argv[0]); - return EX_USAGE; - } - - if(!strcmp(argv[1], "help")) { - help(cout, argv[0]); - return 0; - } - - if(!strcmp(argv[1], "version")) { - version(); - return 0; - } - - if(!strcmp(argv[1], "init")) - return init(); - - if(!strcmp(argv[1], "trust")) - return trust(argc - 2, argv + 2); - - if(!strcmp(argv[1], "dctrust")) - return dctrust(argc - 2, argv + 2); - - if(!strcmp(argv[1], "distrust")) - return distrust(argc - 2, argv + 2); - - if(!strcmp(argv[1], "is_trusted")) - return is_trusted(argc - 2, argv + 2); - - if(!strcmp(argv[1], "is_distrusted")) - return is_distrusted(argc - 2, argv + 2); - - if(!strcmp(argv[1], "is_allowed")) - return is_allowed(argc - 2, argv + 2); - - if(!strcmp(argv[1], "is_denied")) - return is_denied(argc - 2, argv + 2); - - if(!strcmp(argv[1], "allow")) - return allow(argc - 2, argv + 2); - - if(!strcmp(argv[1], "dontcare")) - return dontcare(argc - 2, argv + 2); - - if(!strcmp(argv[1], "deny")) - return deny(argc - 2, argv + 2); - - if(!strcmp(argv[1], "sign")) - return sign(argc - 2, argv + 2); - - if(!strcmp(argv[1], "import")) - return import(argc - 2, argv + 2); - - if(!strcmp(argv[1], "export")) - return exprt(argc - 2, argv + 2); - - if(!strcmp(argv[1], "test")) - return test(argc - 2, argv + 2); - - if(!strcmp(argv[1], "find")) - return find(argc - 2, argv + 2); - - if(!strcmp(argv[1], "fsck")) - return fsck(); - - cerr << "Unknown command: " << argv[1] << '\n'; - return EX_USAGE; -} - diff --git a/fides.h b/fides.h deleted file mode 100644 index 7d94719..0000000 --- a/fides.h +++ /dev/null @@ -1,170 +0,0 @@ -#ifndef __FIDES_H__ -#define __FIDES_H__ - -#include -#include -#include -#include -#include - -class fides { - std::string homedir; - std::string certdir; - std::string obsoletedir; - std::string keydir; - - bool firstrun; - struct timeval latest; - static Botan::AutoSeeded_RNG rng; - - public: - // Utility functions - - static std::string b64encode(const std::string &in); - static std::string b64decode(const std::string &in); - static std::string hexencode(const std::string &in); - static std::string hexdecode(const std::string &in); - - class regexp { - regex_t comp; - - public: - static const int EXTENDED = REG_EXTENDED; - static const int ICASE = REG_ICASE; - static const int NOSUB = REG_NOSUB; - static const int NEWLINE = REG_NEWLINE; - - static const int NOTBOL = REG_NOTBOL; - static const int NOTEAL = REG_NOTEOL; - - regexp(const std::string &exp, int cflags = 0) { - int err = regcomp(&comp, exp.c_str(), cflags | NOSUB); - if(err) - throw exception("Could not compile regular expression"); - } - - ~regexp() { - regfree(&comp); - } - - bool match(const std::string &in, int eflags = 0) { - return regexec(&comp, in.c_str(), 0, 0, eflags) == 0; - } - }; - - // Exception class - - class exception: public std::runtime_error { - public: - exception(const std::string reason): runtime_error(reason) {} - }; - - // Objects manipulated by fides - - class publickey { - protected: - Botan::ECDSA_PublicKey *pub; - - public: - publickey(); - ~publickey(); - - int trust; - void load(std::istream &in); - void save(std::ostream &out); - void load(const std::string &filename); - void save(const std::string &filename); - bool verify(const std::string &data, const std::string &signature); - std::string to_string(); - void from_string(const std::string &in); - std::string fingerprint(unsigned int bits = 64); - }; - - class privatekey: public publickey { - Botan::ECDSA_PrivateKey *priv; - - public: - privatekey(); - ~privatekey(); - - void load_private(std::istream &in); - void save_private(std::ostream &out); - void load_private(const std::string &filename); - void save_private(const std::string &filename); - void generate(const std::string &field); - void generate(unsigned int bits = 224); - std::string sign(const std::string &data); - }; - - class certificate { - friend class fides; - publickey *signer; - struct timeval timestamp; - std::string statement; - std::string signature; - - public: - certificate(publickey *pub, struct timeval timestamp, const std::string &statement, const std::string &signature); - certificate(privatekey *priv, struct timeval timestamp, const std::string &statement); - - std::string to_string() const; - std::string fingerprint(unsigned int bits = 64); - bool validate(); - }; - - // Fides class itself - - private: - privatekey mykey; - std::map keys; - std::map certs; - std::set trustedkeys; - - void merge(certificate *cert); - void merge(publickey *key); - - public: - fides(const std::string &homedir = ""); - ~fides(); - - bool is_firstrun(); - bool fsck(); - std::string get_homedir(); - - void sign(const std::string &statement); - - void allow(const std::string &statement, publickey *key = 0); - void dontcare(const std::string &statement, publickey *key = 0); - void deny(const std::string &statement, publickey *key = 0); - bool is_allowed(const std::string &statement, publickey *key = 0); - bool is_denied(const std::string &statement, publickey *key = 0); - - void auth_stats(const std::string &statement, int &self, int &trusted, int &all); - void trust(publickey *key); - void dctrust(publickey *key); - void distrust(publickey *key); - bool is_trusted(publickey *key); - bool is_distrusted(publickey *key); - publickey *find_key(const std::string &fingerprint); - void update_trust(); - - std::vector find_certificates(publickey *key, const std::string &statement); - std::vector find_certificates(const std::string &statement); - std::vector find_certificates(publickey *key); - - certificate *import_certificate(const std::string &certificate); - std::string export_certificate(const certificate *); - - publickey *import_key(const std::string &key); - std::string export_key(const publickey *key); - - void import_all(std::istream &in); - void export_all(std::ostream &out); - - certificate *certificate_from_string(const std::string &certificate); - certificate *certificate_load(const std::string &filename); - void certificate_save(const certificate *cert, const std::string &filename); - -}; - -#endif diff --git a/lib/Makefile.am b/lib/Makefile.am new file mode 100644 index 0000000..cb39600 --- /dev/null +++ b/lib/Makefile.am @@ -0,0 +1,4 @@ +lib_LTLIBRARIES = libfides.la +libfides_la_SOURCES = fides.cc +include_HEADERS = fides.h +libfides_la_LIBADD = $(BOTAN_LIBS) diff --git a/lib/fides.cc b/lib/fides.cc new file mode 100644 index 0000000..c4dff16 --- /dev/null +++ b/lib/fides.cc @@ -0,0 +1,774 @@ +/* fides.cc - Light-weight, decentralised trust and authorisation management + Copyright (C) 2008-2009 Guus Sliepen + + Fides is free software; you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of + the License, or (at your option) any later version. + + Fides is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this program; if not, see . +*/ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "fides.h" + +using namespace std; + +// Global state + +Botan::LibraryInitializer libinit; +Botan::AutoSeeded_RNG fides::rng; + +// Public key functions + +fides::publickey::publickey(): pub(0), trust(0) { +} + +fides::publickey::~publickey() { + delete pub; +} + +void fides::publickey::load(istream &in) { + try { + Botan::DataSource_Stream source(in); + pub = dynamic_cast(Botan::X509::load_key(source)); + } catch(Botan::Exception &e) { + throw exception(e.what()); + } +} + +void fides::publickey::load(const std::string &filename) { + ifstream in(filename.c_str()); + load(in); +} + +void fides::publickey::save(ostream &out) { + out << to_string(); +} + +void fides::publickey::save(const std::string &filename) { + ofstream out(filename.c_str()); + save(out); +} + +void fides::publickey::from_string(const std::string &in) { + try { + Botan::DataSource_Memory source(in); + pub = dynamic_cast(Botan::X509::load_key(source)); + } catch(Botan::Exception &e) { + throw exception(e.what()); + } +} + +string fides::publickey::to_string() { + return Botan::X509::PEM_encode(*pub); +} + +string fides::publickey::fingerprint(unsigned int bits) { + // TODO: find out if there is a standard way to get a hash of an ECDSA public key + Botan::SHA_256 sha256; + Botan::SecureVector hash = sha256.process(Botan::X509::PEM_encode(*pub)); + return string((const char *)hash.begin(), bits / 8); +} + +bool fides::publickey::verify(const std::string &statement, const std::string &signature) { + auto_ptr verifier(Botan::get_pk_verifier(*pub, "EMSA1(SHA-512)")); + verifier->update((const Botan::byte *)statement.data(), statement.size()); + Botan::SecureVector sig; + sig.set((const Botan::byte *)signature.data(), signature.size()); + return verifier->check_signature(sig); +} + +// Private key functions + +fides::privatekey::privatekey(): priv(0) { +} + +fides::privatekey::~privatekey() { + delete priv; + pub = 0; +} + +void fides::privatekey::generate(const std::string &field) { + Botan::EC_Domain_Params domain = Botan::get_EC_Dom_Pars_by_oid(field); + pub = priv = new Botan::ECDSA_PrivateKey(rng, domain); +} + +void fides::privatekey::generate(unsigned int bits) { + switch(bits) { + case 112: return generate("1.3.132.0.6"); + case 128: return generate("1.3.132.0.28"); + case 160: return generate("1.3.132.0.9"); + case 192: return generate("1.3.132.0.31"); + case 224: return generate("1.3.132.0.32"); + case 256: return generate("1.3.132.0.10"); + case 384: return generate("1.3.132.0.34"); + case 521: return generate("1.3.132.0.35"); + default: throw exception("Unsupported number of bits for private key"); + } +} + +void fides::privatekey::load_private(istream &in) { + try { + Botan::DataSource_Stream stream(in); + pub = priv = dynamic_cast(Botan::PKCS8::load_key(stream, rng, "")); + } catch(Botan::Exception &e) { + throw exception(e.what()); + } +} + +void fides::privatekey::load_private(const std::string &filename) { + ifstream in(filename.c_str()); + load_private(in); +} + +void fides::privatekey::save_private(ostream &out) { + out << Botan::PKCS8::PEM_encode(*priv); +} + +void fides::privatekey::save_private(const std::string &filename) { + ofstream out(filename.c_str()); + save_private(out); +} + +string fides::privatekey::sign(const std::string &statement) { + auto_ptr signer(Botan::get_pk_signer(*priv, "EMSA1(SHA-512)")); + Botan::SecureVector sig = signer->sign_message((const Botan::byte *)statement.data(), statement.size(), rng); + return string((const char *)sig.begin(), (size_t)sig.size()); +} + +// Base64 and hex encoding/decoding functions + +string fides::hexencode(const string &in) { + Botan::Pipe pipe(new Botan::Hex_Encoder); + pipe.process_msg((Botan::byte *)in.data(), in.size()); + return pipe.read_all_as_string(); +} + +string fides::hexdecode(const string &in) { + Botan::Pipe pipe(new Botan::Hex_Decoder); + pipe.process_msg((Botan::byte *)in.data(), in.size()); + return pipe.read_all_as_string(); +} + +string fides::b64encode(const string &in) { + Botan::Pipe pipe(new Botan::Base64_Encoder); + pipe.process_msg((Botan::byte *)in.data(), in.size()); + return pipe.read_all_as_string(); +} + +string fides::b64decode(const string &in) { + Botan::Pipe pipe(new Botan::Base64_Decoder); + pipe.process_msg((Botan::byte *)in.data(), in.size()); + return pipe.read_all_as_string(); +} + +// Certificate functions + +fides::certificate::certificate(publickey *key, struct timeval timestamp, const std::string &statement, const std::string &signature): signer(key), timestamp(timestamp), statement(statement), signature(signature) {} + +bool fides::certificate::validate() { + string data = signer->fingerprint(256); + data += string((const char *)×tamp, sizeof timestamp); + data += statement; + return signer->verify(data, signature); +} + +fides::certificate::certificate(privatekey *key, struct timeval timestamp, const std::string &statement): signer(key), timestamp(timestamp), statement(statement) { + string data = signer->fingerprint(256); + data += string((const char *)×tamp, sizeof timestamp); + data += statement; + signature = key->sign(data); +} + +string fides::certificate::fingerprint(unsigned int bits) { + return signature.substr(signature.size() - bits / 8); +} + +string fides::certificate::to_string() const { + string data = fides::hexencode(signer->fingerprint()); + data += ' '; + char ts[100]; + snprintf(ts, sizeof ts, "%lu.%06lu", timestamp.tv_sec, timestamp.tv_usec); + data += ts; + data += ' '; + data += fides::b64encode(signature); + data += ' '; + data += statement; + return data; +} + +// Utility functions + +static vector dirlist(const string &path) { + vector files; + + DIR *dir = opendir(path.c_str()); + if(!dir) + return files; + + struct dirent entry, *result = &entry; + + while(result) { + readdir_r(dir, &entry, &result); + if(!result) + break; + struct stat st; + if(result->d_type == DT_UNKNOWN) { + if(stat((path + "/" + result->d_name).c_str(), &st)) + continue; + if(S_ISREG(st.st_mode)) + files.push_back(result->d_name); + } else if(result->d_type == DT_REG) { + files.push_back(result->d_name); + } + } + + closedir(dir); + + return files; +} + +void fides::certificate_save(const certificate *cert, const string &filename) { + ofstream file(filename.c_str()); + file << cert->to_string() << '\n'; +} + +fides::certificate *fides::certificate_load(const string &filename) { + ifstream file(filename.c_str()); + string data; + getline(file, data); + return certificate_from_string(data); +} + +fides::certificate *fides::certificate_from_string(const string &data) { + size_t b, e; + e = data.find(' ', 0); + if(e == string::npos) + throw exception("Invalid certificate"); + string fingerprint = hexdecode(data.substr(0, e)); + publickey *signer = find_key(fingerprint); + if(!signer) + throw exception("Unknown public key"); + b = e + 1; + e = data.find('.', b); + if(e == string::npos) + throw exception("Invalid certificate"); + struct timeval timestamp; + timestamp.tv_sec = atol(data.c_str() + b); + b = e + 1; + timestamp.tv_usec = atol(data.c_str() + b); + e = data.find(' ', b); + if(e == string::npos) + throw exception("Invalid certificate"); + b = e + 1; + e = data.find(' ', b); + if(e == string::npos) + throw exception("Invalid certificate"); + string signature = fides::b64decode(data.substr(b, e - b)); + b = e + 1; + string statement = data.substr(b); + + return new certificate(signer, timestamp, statement, signature); +} + +// Fides main functions + +fides::fides(const string &dir): homedir(dir) { + cerr << "Fides initialising\n"; + + // Set homedir to provided directory, or $FIDES_HOME, or $HOME/.fides, or as a last resort $PWD/.fides + if(homedir.empty()) + homedir = getenv("FIDES_HOME") ?: ""; + if(homedir.empty()) { + char cwd[PATH_MAX]; + homedir = getenv("HOME") ?: getcwd(cwd, sizeof cwd); + homedir += "/.fides"; + } + + // Derived directories + homedir += '/'; + certdir = homedir + "certs/"; + keydir = homedir + "keys/"; + obsoletedir = homedir + ".obsolete_certs/"; + + // Ensure the homedir and its subdirectories exist + mkdir(homedir.c_str(), 0700); + mkdir(certdir.c_str(), 0700); + mkdir(keydir.c_str(), 0700); + mkdir(obsoletedir.c_str(), 0700); + + try { + mykey.load_private(homedir + "priv"); + firstrun = false; + } catch(fides::exception &e) { + cerr << "Fides generating keypair\n"; + mykey.generate(); + mykey.save_private(homedir + "priv"); + mykey.save(keydir + hexencode(mykey.fingerprint())); + firstrun = true; + } + vector files = dirlist(keydir); + for(size_t i = 0; i < files.size(); ++i) { + cerr << "Loading key " << files[i] << '\n'; + + publickey *key = new publickey(); + key->load(keydir + files[i]); + keys[hexdecode(files[i])] = key; + } + + keys[mykey.fingerprint()] = &mykey; + + files = dirlist(certdir); + for(size_t i = 0; i < files.size(); ++i) { + cerr << "Loading certificate " << files[i] << '\n'; + certificate *cert = certificate_load(certdir + files[i]); + if(false && !cert->validate()) { + cerr << "Bad certificate!\n"; + continue; + } + certs[hexdecode(files[i])] = cert; + } + + // TODO: save and load this value + latest.tv_sec = 0; + latest.tv_usec = 0; + + update_trust(); +} + +fides::~fides() { + cerr << "Fides exitting\n"; + for(map::iterator i = certs.begin(); i != certs.end(); ++i) + delete i->second; + for(map::iterator i = keys.begin(); i != keys.end(); ++i) + if(i->second != &mykey) + delete i->second; +} + +bool fides::fsck() { + int errors = 0; + + for(map::iterator i = certs.begin(); i != certs.end(); ++i) { + if(!i->second->validate()) { + cerr << "Validation of certificate failed: " << i->second->to_string() << '\n'; + errors++; + } + } + + cerr << errors << " errors in " << certs.size() << " certificates\n"; + return !errors; +} + +string fides::get_homedir() { + return homedir; +} + +bool fides::is_firstrun() { + return firstrun; +} + +fides::publickey *fides::find_key(const string &fingerprint) { + map::iterator i; + i = keys.find(fingerprint); + if(i != keys.end()) + return i->second; + else + return 0; +} + +vector fides::find_certificates(publickey *signer, const string ®ex) { + vector found; + map::iterator i; + regexp regexp(regex); + for(i = certs.begin(); i != certs.end(); ++i) { + if(!i->second) { + cerr << "No certificate for " << hexencode(i->first) << '\n'; + continue; + } + if(i->second->signer == signer) + if(regexp.match(i->second->statement)) + found.push_back(i->second); + } + return found; +} + +vector fides::find_certificates(const string ®ex) { + vector found; + map::iterator i; + regexp regexp(regex); + for(i = certs.begin(); i != certs.end(); ++i) + if(regexp.match(i->second->statement)) + found.push_back(i->second); + return found; +} + +vector fides::find_certificates(publickey *signer) { + vector found; + map::iterator i; + for(i = certs.begin(); i != certs.end(); ++i) + if(i->second->signer == signer) + found.push_back(i->second); + return found; +} + +void fides::import_all(istream &in) { + string line, pem; + bool is_pem = false; + + while(getline(in, line)) { + if(line.empty()) + continue; + + if(is_pem || !line.compare(0, 11, "-----BEGIN ")) { + pem += line + '\n'; + if(!line.compare(0, 9, "-----END ")) { + fides::publickey *key = new publickey(); + key->from_string(pem); + cerr << "Imported key " << hexencode(key->fingerprint()) << '\n'; + merge(key); + is_pem = false; + } else { + is_pem = true; + } + continue; + } + + fides::certificate *cert = certificate_from_string(line); + cerr << "Importing certificate " << hexencode(cert->fingerprint()) << '\n'; + merge(cert); + } +} + +void fides::export_all(ostream &out) { + for(map::iterator i = keys.begin(); i != keys.end(); ++i) + out << i->second->to_string(); + for(map::iterator i = certs.begin(); i != certs.end(); ++i) + out << i->second->to_string() << '\n'; +} + +void fides::trust(publickey *key) { + string full = "t+ " + hexencode(key->fingerprint()); + sign(full); +} + +void fides::distrust(publickey *key) { + string full = "t- " + hexencode(key->fingerprint()); + sign(full); +} + +void fides::dctrust(publickey *key) { + string full = "t0 " + hexencode(key->fingerprint()); + sign(full); +} + +void fides::update_trust() { + // clear trust on all keys + for(map::iterator i = keys.begin(); i != keys.end(); ++i) + i->second->trust = 0; + + // Start by checking all trust certificates from ourself. + // If another key is positively or negatively trusted, update its trust score + // and add it to the the list of new keys to check. + // Then add our own key to the list of already checked keys. + // Then check all the trust certificates of those on the tocheck list, etc. + // Already checked keys are never updated anymore (TODO: is that smart?) + // Certificates of keys with a zero or negative trust score are not processed. + + set checked; + set tocheck; + set newkeys; + set::iterator i; + + mykey.trust = 3; + tocheck.insert(&mykey); + + while(tocheck.size()) { + // add + checked.insert(tocheck.begin(), tocheck.end()); + newkeys.clear(); + + // loop over all keys whose certificates need to be checked + + for(i = tocheck.begin(); i != tocheck.end(); ++i) { + cerr << "Trust for key " << hexencode((*i)->fingerprint()) << " set to " << (*i)->trust << '\n'; + + // except if this key is not trusted + + if((*i)->trust <= 0) + continue; + + // find all non-zero trust certificates of this key + + vector matches = find_certificates(*i, "^t[+-] "); + + // update trust value of those keys + + for(size_t j = 0; j < matches.size(); j++) { + publickey *other = find_key(hexdecode(matches[j]->statement.substr(3))); + + if(!other) { + cerr << "Trust certificate for unknown key: " << matches[j]->to_string() << '\n'; + continue; + } + + // except for keys we already checked + + if(checked.find(other) != checked.end()) { + cerr << "Skipping trust certificate for already checked key: " << matches[j]->to_string() << '\n'; + continue; + } + + // update trust + + if(matches[j]->statement[1] == '+') + other->trust++; + else + other->trust--; + + newkeys.insert(other); + } + } + + tocheck = newkeys; + } +} + +void fides::merge(publickey *key) { + if(keys.find(key->fingerprint()) != keys.end()) { + cerr << "Key already known\n"; + return; + } + + keys[key->fingerprint()] = key; + key->save(keydir + hexencode(key->fingerprint())); +} + +void fides::merge(certificate *cert) { + // TODO: check if cert is already in database + // TODO: check if cert obsoletes other certs + + // If we already know this certificate, drop it. + if(certs.find(cert->fingerprint()) != certs.end()) { + cerr << "Certificate already known\n"; + return; + } + + // If the certificate does not validate, drop it. + if(!cert->validate()) { + // TODO: this should not happen, be wary of DoS attacks + cerr << "Certificate invalid\n"; + return; + } + + // TODO: move these regexps to the class? + regexp authexp("^a[+0-] "); + regexp trustexp("^t[+0-] "); + vector others; + + // Is this an authorisation cert? + if(authexp.match(cert->statement)) { + // Find certs identical except for the +/-/0 + // TODO: escape statement in regexp + others = find_certificates(cert->signer, string("^a[+0-] ") + cert->statement.substr(3) + '$'); + if(others.size()) { + if(timercmp(&others[0]->timestamp, &cert->timestamp, >)) { + cerr << "Certificate is overruled by a newer certificate\n"; + return; + } + if(timercmp(&others[0]->timestamp, &cert->timestamp, ==)) { + // TODO: this should not happen, be wary of DoS attacks + cerr << "Certificate has same timestamp as another timestamp!\n"; + return; + } + cerr << "Certificate overrules an older certificate!\n"; + // save new cert first + certificate_save(cert, certdir + hexencode(cert->fingerprint())); + certs[cert->fingerprint()] = cert; + + // delete old one + rename((certdir + hexencode(others[0]->fingerprint())).c_str(), (obsoletedir + hexencode(others[0]->fingerprint())).c_str()); + certs.erase(others[0]->fingerprint()); + delete others[0]; + return; + } + } + + // Is this a trust cert? + // TODO: it's just the same as above! + if(trustexp.match(cert->statement)) { + // Find certs identical except for the +/-/0 + // TODO: escape statement in regexp + others = find_certificates(cert->signer, string("^t[+0-] ") + cert->statement.substr(3) + '$'); + if(others.size()) { + if(timercmp(&others[0]->timestamp, &cert->timestamp, >)) { + cerr << "Certificate is overruled by a newer certificate\n"; + return; + } + if(timercmp(&others[0]->timestamp, &cert->timestamp, ==)) { + // TODO: this should not happen, be wary of DoS attacks + cerr << "Certificate has same timestamp as another timestamp!\n"; + return; + } + cerr << "Certificate overrules an older certificate!\n"; + // delete old one + rename((certdir + hexencode(others[0]->fingerprint())).c_str(), (obsoletedir + hexencode(others[0]->fingerprint())).c_str()); + certs.erase(others[0]->fingerprint()); + delete others[0]; + certs[cert->fingerprint()] = cert; + certificate_save(cert, certdir + hexencode(cert->fingerprint())); + return; + } + } + + // Did somebody sign the exact same statement twice? + // Could happen if there is a different, conflicting statement between this new and the corresponding old one. + others = find_certificates(cert->signer, string("^") + cert->statement + '$'); + if(others.size()) { + if(timercmp(&others[0]->timestamp, &cert->timestamp, >)) { + cerr << "Certificate is overruled by a newer certificate\n"; + return; + } + if(timercmp(&others[0]->timestamp, &cert->timestamp, ==)) { + // TODO: this should not happen, be wary of DoS attacks + cerr << "Certificate has same timestamp as another timestamp!\n"; + return; + } + cerr << "Certificate overrules an older certificate!\n"; + // delete old one + rename((certdir + hexencode(others[0]->fingerprint())).c_str(), (obsoletedir + hexencode(others[0]->fingerprint())).c_str()); + certs.erase(others[0]->fingerprint()); + delete others[0]; + certs[cert->fingerprint()] = cert; + certificate_save(cert, certdir + hexencode(cert->fingerprint())); + return; + } + + cerr << "Certificate is new\n"; + certs[cert->fingerprint()] = cert; + certificate_save(cert, certdir + hexencode(cert->fingerprint())); +} + +void fides::auth_stats(const string &statement, int &self, int &trusted, int &all) { + self = trusted = all = 0; + vector matches = find_certificates(string("^a[+0-] ") + statement + '$'); + for(size_t i = 0; i < matches.size(); ++i) { + char code = matches[i]->statement[1]; + int diff = 0; + if(code == '+') + diff = 1; + else if(code == '-') + diff = -1; + if(matches[i]->signer == &mykey) + self += diff; + if(matches[i]->signer->trust > 0) + trusted += diff; + all += diff; + } +} + +bool fides::is_trusted(publickey *key) { + return key->trust > 0; +} + +bool fides::is_distrusted(publickey *key) { + return key->trust < 0; +} + +bool fides::is_allowed(const string &statement, publickey *key) { + int self, trusted, all; + + if(key) + auth_stats(hexencode(key->fingerprint()) + " " + statement, self, trusted, all); + else + auth_stats(statement, self, trusted, all); + + if(self) + return self > 0; + else if(trusted) + return trusted > 0; + else + return false; +} + +bool fides::is_denied(const string &statement, publickey *key) { + int self, trusted, all; + + if(key) + auth_stats(hexencode(key->fingerprint()) + " " + statement, self, trusted, all); + else + auth_stats(statement, self, trusted, all); + + if(self) + return self < 0; + else if(trusted) + return trusted < 0; + else + return false; +} + +void fides::sign(const string &statement) { + // Try to set "latest" to now, but ensure monoticity + struct timeval now; + gettimeofday(&now, 0); + if(timercmp(&latest, &now, >=)) { + latest.tv_usec++; + if(latest.tv_usec >= 1000000) { + latest.tv_sec++; + latest.tv_usec -= 1000000; + } + } else { + latest = now; + } + + // Create a new certificate and merge it with our database + merge(new certificate(&mykey, latest, statement)); +} + +void fides::allow(const string &statement, publickey *key) { + string full = "a+ "; + if(key) + full += hexencode(key->fingerprint()) + ' '; + full += statement; + sign(full); +} + +void fides::dontcare(const string &statement, publickey *key) { + string full = "a0 "; + if(key) + full += hexencode(key->fingerprint()) + ' '; + full += statement; + sign(full); +} + +void fides::deny(const string &statement, publickey *key) { + string full = "a- "; + if(key) + full += hexencode(key->fingerprint()) + ' '; + full += statement; + sign(full); +} + diff --git a/lib/fides.h b/lib/fides.h new file mode 100644 index 0000000..7d94719 --- /dev/null +++ b/lib/fides.h @@ -0,0 +1,170 @@ +#ifndef __FIDES_H__ +#define __FIDES_H__ + +#include +#include +#include +#include +#include + +class fides { + std::string homedir; + std::string certdir; + std::string obsoletedir; + std::string keydir; + + bool firstrun; + struct timeval latest; + static Botan::AutoSeeded_RNG rng; + + public: + // Utility functions + + static std::string b64encode(const std::string &in); + static std::string b64decode(const std::string &in); + static std::string hexencode(const std::string &in); + static std::string hexdecode(const std::string &in); + + class regexp { + regex_t comp; + + public: + static const int EXTENDED = REG_EXTENDED; + static const int ICASE = REG_ICASE; + static const int NOSUB = REG_NOSUB; + static const int NEWLINE = REG_NEWLINE; + + static const int NOTBOL = REG_NOTBOL; + static const int NOTEAL = REG_NOTEOL; + + regexp(const std::string &exp, int cflags = 0) { + int err = regcomp(&comp, exp.c_str(), cflags | NOSUB); + if(err) + throw exception("Could not compile regular expression"); + } + + ~regexp() { + regfree(&comp); + } + + bool match(const std::string &in, int eflags = 0) { + return regexec(&comp, in.c_str(), 0, 0, eflags) == 0; + } + }; + + // Exception class + + class exception: public std::runtime_error { + public: + exception(const std::string reason): runtime_error(reason) {} + }; + + // Objects manipulated by fides + + class publickey { + protected: + Botan::ECDSA_PublicKey *pub; + + public: + publickey(); + ~publickey(); + + int trust; + void load(std::istream &in); + void save(std::ostream &out); + void load(const std::string &filename); + void save(const std::string &filename); + bool verify(const std::string &data, const std::string &signature); + std::string to_string(); + void from_string(const std::string &in); + std::string fingerprint(unsigned int bits = 64); + }; + + class privatekey: public publickey { + Botan::ECDSA_PrivateKey *priv; + + public: + privatekey(); + ~privatekey(); + + void load_private(std::istream &in); + void save_private(std::ostream &out); + void load_private(const std::string &filename); + void save_private(const std::string &filename); + void generate(const std::string &field); + void generate(unsigned int bits = 224); + std::string sign(const std::string &data); + }; + + class certificate { + friend class fides; + publickey *signer; + struct timeval timestamp; + std::string statement; + std::string signature; + + public: + certificate(publickey *pub, struct timeval timestamp, const std::string &statement, const std::string &signature); + certificate(privatekey *priv, struct timeval timestamp, const std::string &statement); + + std::string to_string() const; + std::string fingerprint(unsigned int bits = 64); + bool validate(); + }; + + // Fides class itself + + private: + privatekey mykey; + std::map keys; + std::map certs; + std::set trustedkeys; + + void merge(certificate *cert); + void merge(publickey *key); + + public: + fides(const std::string &homedir = ""); + ~fides(); + + bool is_firstrun(); + bool fsck(); + std::string get_homedir(); + + void sign(const std::string &statement); + + void allow(const std::string &statement, publickey *key = 0); + void dontcare(const std::string &statement, publickey *key = 0); + void deny(const std::string &statement, publickey *key = 0); + bool is_allowed(const std::string &statement, publickey *key = 0); + bool is_denied(const std::string &statement, publickey *key = 0); + + void auth_stats(const std::string &statement, int &self, int &trusted, int &all); + void trust(publickey *key); + void dctrust(publickey *key); + void distrust(publickey *key); + bool is_trusted(publickey *key); + bool is_distrusted(publickey *key); + publickey *find_key(const std::string &fingerprint); + void update_trust(); + + std::vector find_certificates(publickey *key, const std::string &statement); + std::vector find_certificates(const std::string &statement); + std::vector find_certificates(publickey *key); + + certificate *import_certificate(const std::string &certificate); + std::string export_certificate(const certificate *); + + publickey *import_key(const std::string &key); + std::string export_key(const publickey *key); + + void import_all(std::istream &in); + void export_all(std::ostream &out); + + certificate *certificate_from_string(const std::string &certificate); + certificate *certificate_load(const std::string &filename); + void certificate_save(const certificate *cert, const std::string &filename); + +}; + +#endif diff --git a/src/Makefile.am b/src/Makefile.am new file mode 100644 index 0000000..3a5b9e9 --- /dev/null +++ b/src/Makefile.am @@ -0,0 +1,11 @@ +AM_CPPFLAGS = \ + -I$(top_srcdir)/lib + +bin_PROGRAMS = fides + +fides_SOURCES = fides.cc + +noinst_HEADERS = + +fides_LDADD = \ + $(top_srcdir)/lib/libfides.la diff --git a/src/fides.cc b/src/fides.cc new file mode 100644 index 0000000..006b503 --- /dev/null +++ b/src/fides.cc @@ -0,0 +1,382 @@ +/* fides.c - Light-weight, decentralised trust and authorisation management + Copyright (C) 2008-2009 Guus Sliepen + + Fides is free software; you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of + the License, or (at your option) any later version. + + Fides is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this program; if not, see . +*/ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "fides.h" + +using namespace std; + +static void help(ostream &out, const string &argv0) { + out << "Usage: " << argv0 << " [arguments]\n" + "\n" + "Available commands are:\n" + "\n" + " init Initialise fides, generate a public/private keypair.\n" + " version Show version and copyright information.\n" + " help Show this help message.\n" + "\n" + " trust \n" + " Trust allow/deny packets signed by the specified key.\n" + " distrust \n" + " Distrust allow/deny packets signed by the specified key.\n" + " dctrust \n" + " Don't care about allow/deny packets signed by the specified key.\n" + " is_trusted \n" + " Returns 0 if key is trusted, 1 otherwise\n" + " is_distrusted \n" + " Returns 0 if key is distrusted, 1 otherwise\n" + "\n" + " sign \n" + " Sign stuff.\n" + " allow \n" + " Allow stuff.\n" + " deny \n" + " Deny stuff.\n" + " dontcare \n" + " Don't care about stuff.\n" + " is_allowed \n" + " Returns 0 if stuff is allowed, 1 otherwise\n" + " is_denied \n" + " Returns 0 if stuff is denied, 1 otherwise\n" + "\n" + " import [filename]\n" + " Import keys and certificates from file, or stdin if unspecified.\n" + " export [filename]\n" + " Export keys and certificates to file, or stdout if unspecified.\n" + " test \n" + " Tell whether stuff is allowed or not by counting relevant certificates\n" + " find \n" + " Find all certificates matching regexp\n" + " fsck Verify the signature on all information collected.\n"; +} + +static void version(ostream &out = cout) { + out << "fides version 0.1\n" + "Copyright (c) 2008-2009 Guus Sliepen \n" + "\n" + "This program is free software; you can redistribute it and/or modify\n" + "it under the terms of the GNU General Public License as published by\n" + "the Free Software Foundation; either version 2 of the License, or\n" + "(at your option) any later version.\n"; +} + +static int init() { + fides fides; + if(fides.is_firstrun()) { + cout << "New keys generated in " << fides.get_homedir() << '\n'; + } else { + cout << "Fides already initialised\n"; + } + return 0; +} + +static int is_trusted(int argc, char *const argv[]) { + if(argc < 1) + return EX_USAGE; + + fides fides; + fides::publickey *key = fides.find_key(fides::hexdecode(argv[0])); + if(!key) { + cerr << "Unknown key!\n"; + return 1; + } + return fides.is_trusted(key) ? 0 : 1; +} + +static int is_distrusted(int argc, char *const argv[]) { + if(argc < 1) + return EX_USAGE; + + fides fides; + fides::publickey *key = fides.find_key(fides::hexdecode(argv[0])); + if(!key) { + cerr << "Unknown key!\n"; + return 1; + } + return fides.is_distrusted(key) ? 0 : 1; +} + +static int trust(int argc, char *const argv[]) { + if(argc < 1) + return EX_USAGE; + + fides fides; + fides::publickey *key = fides.find_key(fides::hexdecode(argv[0])); + if(key) + fides.trust(key); + else { + cerr << "Unknown key!\n"; + return -1; + } + return 0; +} + +static int dctrust(int argc, char *const argv[]) { + if(argc < 1) + return EX_USAGE; + + fides fides; + fides::publickey *key = fides.find_key(fides::hexdecode(argv[0])); + if(key) + fides.dctrust(key); + else { + cerr << "Unknown key!\n"; + return -1; + } + return 0; +} + +static int distrust(int argc, char *const argv[]) { + if(argc < 1) + return EX_USAGE; + + fides fides; + fides::publickey *key = fides.find_key(fides::hexdecode(argv[0])); + if(key) + fides.distrust(key); + else { + cerr << "Unknown key!\n"; + return -1; + } + return 0; +} + +static int sign(int argc, char *const argv[]) { + if(argc < 1) + return EX_USAGE; + + fides fides; + fides.sign(argv[0]); + return 0; +} + +static int allow(int argc, char *const argv[]) { + if(argc < 1) + return EX_USAGE; + + fides fides; + fides.allow(argv[0]); + return 0; +} + +static int dontcare(int argc, char *const argv[]) { + if(argc < 1) + return EX_USAGE; + + fides fides; + fides.dontcare(argv[0]); + return 0; +} + +static int deny(int argc, char *const argv[]) { + if(argc < 1) + return EX_USAGE; + + fides fides; + fides.deny(argv[0]); + return 0; +} + +static int import(int argc, char *const argv[]) { + fides fides; + + if(argc) { + ifstream in(argv[0]); + fides.import_all(in); + } else + fides.import_all(cin); + return 0; +} + +static int exprt(int argc, char *const argv[]) { + fides fides; + + if(argc) { + ofstream out(argv[0]); + fides.export_all(out); + } else + fides.export_all(cout); + return 0; +} + +static int find(int argc, char *const argv[]) { + if(argc < 1) + return EX_USAGE; + + // Find certificates matching statement + fides fides; + const vector &certs = fides.find_certificates(argv[0]); + for(size_t i = 0; i < certs.size(); ++i) + cout << i << ' ' << certs[i]->to_string() << '\n'; + return 0; +} + +static int is_allowed(int argc, char *const argv[]) { + if(argc < 1) + return EX_USAGE; + + fides fides; + return fides.is_allowed(argv[0]) ? 0 : 1; +} + +static int is_denied(int argc, char *const argv[]) { + if(argc < 1) + return EX_USAGE; + + fides fides; + return fides.is_denied(argv[0]) ? 0 : 1; +} + +static int test(int argc, char *const argv[]) { + if(argc < 1) + return EX_USAGE; + + fides fides; + int self, trusted, all; + fides.auth_stats(argv[0], self, trusted, all); + cout << "Self: " << self << ", trusted: " << trusted << ", all: " << all << '\n'; + return 0; +} + +static int fsck() { + fides fides; + if(fides.fsck()) { + cout << "Everything OK\n"; + return 0; + } else { + cout << "Integrity failure!\n"; + return 1; + } +} + +int main(int argc, char *const argv[]) { + int r; + int option_index; + + static struct option const long_options[] = { + {"homedir", required_argument, NULL, 2}, + {"help", no_argument, NULL, 'h'}, + {"version", no_argument, NULL, 3}, + {NULL, 0, NULL, 0} + }; + + while((r = getopt_long(argc, argv, "h", long_options, &option_index)) != EOF) { + switch (r) { + case 0: /* long option */ + break; + case 1: /* non-option */ + break; + case 2: + //homedir = strdup(optarg); + break; + case 3: + version(); + return 0; + case 'h': + help(cout, argv[0]); + return 0; + } + } + + if(argc < 2) { + help(cerr, argv[0]); + return EX_USAGE; + } + + if(!strcmp(argv[1], "help")) { + help(cout, argv[0]); + return 0; + } + + if(!strcmp(argv[1], "version")) { + version(); + return 0; + } + + if(!strcmp(argv[1], "init")) + return init(); + + if(!strcmp(argv[1], "trust")) + return trust(argc - 2, argv + 2); + + if(!strcmp(argv[1], "dctrust")) + return dctrust(argc - 2, argv + 2); + + if(!strcmp(argv[1], "distrust")) + return distrust(argc - 2, argv + 2); + + if(!strcmp(argv[1], "is_trusted")) + return is_trusted(argc - 2, argv + 2); + + if(!strcmp(argv[1], "is_distrusted")) + return is_distrusted(argc - 2, argv + 2); + + if(!strcmp(argv[1], "is_allowed")) + return is_allowed(argc - 2, argv + 2); + + if(!strcmp(argv[1], "is_denied")) + return is_denied(argc - 2, argv + 2); + + if(!strcmp(argv[1], "allow")) + return allow(argc - 2, argv + 2); + + if(!strcmp(argv[1], "dontcare")) + return dontcare(argc - 2, argv + 2); + + if(!strcmp(argv[1], "deny")) + return deny(argc - 2, argv + 2); + + if(!strcmp(argv[1], "sign")) + return sign(argc - 2, argv + 2); + + if(!strcmp(argv[1], "import")) + return import(argc - 2, argv + 2); + + if(!strcmp(argv[1], "export")) + return exprt(argc - 2, argv + 2); + + if(!strcmp(argv[1], "test")) + return test(argc - 2, argv + 2); + + if(!strcmp(argv[1], "find")) + return find(argc - 2, argv + 2); + + if(!strcmp(argv[1], "fsck")) + return fsck(); + + cerr << "Unknown command: " << argv[1] << '\n'; + return EX_USAGE; +}