X-Git-Url: https://git.saurik.com/apple/security.git/blobdiff_plain/d8f41ccd20de16f8ebe2ccc84d47bf1cb2b26bbb..5c19dc3ae3bd8e40a9c028b0deddd50ff337692c:/securityd/src/codesigdb.cpp diff --git a/securityd/src/codesigdb.cpp b/securityd/src/codesigdb.cpp index c06a7582..80f3af67 100644 --- a/securityd/src/codesigdb.cpp +++ b/securityd/src/codesigdb.cpp @@ -34,86 +34,23 @@ #include -// -// A self-constructing database key class. -// Key format is -// where -// single ASCII character type code ('H' for hash links) -// decimal userid of owning user, or 'S' for system entries. Followed by null byte. -// variable length key value (binary). -// -class DbKey : public CssmAutoData { -public: - DbKey(char type, const CssmData &key, bool perUser = false, uid_t user = 0); -}; - -DbKey::DbKey(char type, const CssmData &key, bool perUser, uid_t user) - : CssmAutoData(Allocator::standard()) -{ - using namespace LowLevelMemoryUtilities; - char header[20]; - size_t headerLength; - if (perUser) - headerLength = 1 + sprintf(header, "%c%d", type, user); - else - headerLength = 1 + sprintf(header, "%cS", type); - malloc(headerLength + key.length()); - memcpy(this->data(), header, headerLength); - memcpy(get().at(headerLength), key.data(), key.length()); -} - - -// -// A subclass of Identity made of whole cloth (from a raw CodeSignature ACL information) -// -struct AclIdentity : public CodeSignatures::Identity { - AclIdentity(const CssmData hash, string path) : mHash(hash), mPath(path) { } - - string getPath() const { return mPath; } - const CssmData getHash() const { return mHash; } - -private: - const CssmData mHash; - const string mPath; -}; - - // // Construct a CodeSignatures objects // -CodeSignatures::CodeSignatures(const char *path) +CodeSignatures::CodeSignatures() { - try { - mDb.open(path, O_RDWR | O_CREAT, 0644); - } catch (const CommonError &err) { - try { - mDb.open(path, O_RDONLY, 0644); - Syslog::warning("database %s opened READONLY (R/W failed errno=%d)", path, err.unixError()); - secdebug("codesign", "database %s opened READONLY (R/W failed errno=%d)", path, err.unixError()); - } catch (...) { - Syslog::warning("cannot open %s; using no code equivalents", path); - secdebug("codesign", "unable to open %s; using no code equivalents", path); - } - } - if (mDb) - mDb.flush(); // in case we just created it - IFDUMPING("equiv", debugDump("open")); } CodeSignatures::~CodeSignatures() { } - // // (Re)open the equivalence database. // This is useful to switch to database in another volume. // void CodeSignatures::open(const char *path) { - mDb.open(path, O_RDWR | O_CREAT, 0644); - mDb.flush(); - IFDUMPING("equiv", debugDump("reopen")); } @@ -126,96 +63,6 @@ CodeSignatures::Identity::Identity() : mState(untried) CodeSignatures::Identity::~Identity() { } -string CodeSignatures::Identity::canonicalName(const string &path) -{ - string::size_type slash = path.rfind('/'); - if (slash == string::npos) // bloody unlikely, but whatever... - return path; - return path.substr(slash+1); -} - - -// -// Find and store database objects (primitive layer) -// -bool CodeSignatures::find(Identity &id, uid_t user) -{ - if (id.mState != Identity::untried) - return id.mState == Identity::valid; - try { - DbKey userKey('H', id.getHash(), true, user); - CssmData linkValue; - if (mDb.get(userKey, linkValue)) { - id.mName = string(linkValue.interpretedAs(), linkValue.length()); - IFDUMPING("equiv", id.debugDump("found/user")); - id.mState = Identity::valid; - return true; - } - DbKey sysKey('H', id.getHash()); - if (mDb.get(sysKey, linkValue)) { - id.mName = string(linkValue.interpretedAs(), linkValue.length()); - IFDUMPING("equiv", id.debugDump("found/system")); - id.mState = Identity::valid; - return true; - } - } catch (...) { - secdebug("codesign", "exception validating identity for %s - marking failed", id.path().c_str()); - id.mState = Identity::invalid; - } - return id.mState == Identity::valid; -} - -void CodeSignatures::makeLink(Identity &id, const string &ident, bool forUser, uid_t user) -{ - DbKey key('H', id.getHash(), forUser, user); - if (!mDb.put(key, StringData(ident))) - UnixError::throwMe(); -} - - -// -// Administrative manipulation calls -// -void CodeSignatures::addLink(const CssmData &oldHash, const CssmData &newHash, - const char *inName, bool forSystem) -{ - string name = Identity::canonicalName(inName); - uid_t user = Server::process().uid(); - if (forSystem && user) // only root user can establish forSystem links - UnixError::throwMe(EACCES); - if (!forSystem) // in fact, for now we don't allow per-user calls at all - UnixError::throwMe(EACCES); - AclIdentity oldCode(oldHash, name); - AclIdentity newCode(newHash, name); - secdebug("codesign", "addlink for name %s", name.c_str()); - StLock _(mDatabaseLock); - if (oldCode) { - if (oldCode.trustedName() != name) { - secdebug("codesign", "addlink does not match existing name %s", - oldCode.trustedName().c_str()); - MacOSError::throwMe(CSSMERR_CSP_VERIFY_FAILED); - } - } else { - makeLink(oldCode, name, !forSystem, user); - } - if (!newCode) - makeLink(newCode, name, !forSystem, user); - mDb.flush(); -} - -void CodeSignatures::removeLink(const CssmData &hash, const char *name, bool forSystem) -{ - AclIdentity code(hash, name); - uid_t user = Server::process().uid(); - if (forSystem && user) // only root user can remove forSystem links - UnixError::throwMe(EACCES); - DbKey key('H', hash, !forSystem, user); - StLock _(mDatabaseLock); - mDb.erase(key); - mDb.flush(); -} - - // // Verify signature matches. // This ends up getting called when a CodeSignatureAclSubject is validated. @@ -254,17 +101,33 @@ bool CodeSignatures::verify(Process &process, switch (matchSignedClientToLegacyACL(process, code, verifier, context)) { case noErr: // handled, allow access return true; - case errSecCSUnsigned: // unsigned client, complete legacy case - secdebug("codesign", "no CS requirement - using legacy hash"); - return verifyLegacy(process, - CssmData::wrap(verifier.legacyHash(), SHA1::digestLength), - verifier.path()); + case errSecCSUnsigned: { // unsigned client, complete legacy case + secdebug("codesign", "no CS requirement - using legacy hash"); + + /* + * We should stop supporting this case for binanaries + * built for modern OS/SDK, user should ad-hoc sign + * their binaries in that case. + * + * + */ + Identity &clientIdentity = process; + try { + if (clientIdentity.getHash() == CssmData::wrap(verifier.legacyHash(), SHA1::digestLength)) { + secdebug("codesign", "direct match: pass"); + return true; + } + } catch (...) { + secdebug("codesign", "exception getting client code hash: fail"); + return false; + } + return false; + } default: // client unsuitable, reject this match return false; } } - // // See if we can rewrite the ACL from legacy to Code Signing form without losing too much security. // Returns true if the present validation should succeed (we probably rewrote the ACL). @@ -379,171 +242,3 @@ OSStatus CodeSignatures::matchSignedClientToLegacyACL(Process &process, // not close enough to even ask - this can't match return errSecCSReqFailed; } - - -// -// Perform legacy hash verification. -// This is the pre-Leopard (Tiger, Panther) code path. Here we only have legacy hashes -// (called, confusingly, "signatures"), which we're matching against suitably computed -// "signatures" (hashes) on the requesting application. We consult the CodeEquivalenceDatabase -// in a doomed attempt to track changes made to applications through updates, and issue -// equivalence dialogs to users if we have a name match (but hash mismatch). That's all -// there was before Code Signing; and that's what you'll continue to get if the requesting -// application is unsigned. Until we throw the whole mess out altogether, hopefully by -// the Next Big Cat After Leopard. -// -bool CodeSignatures::verifyLegacy(Process &process, const CssmData &signature, string path) -{ - // First of all, if the signature directly matches the client's code, we're obviously fine - // we don't even need the database for that... - Identity &clientIdentity = process; - try { - if (clientIdentity.getHash() == signature) { - secdebug("codesign", "direct match: pass"); - return true; - } - } catch (...) { - secdebug("codesign", "exception getting client code hash: fail"); - return false; - } - -#if CONSULT_LEGACY_CODE_EQUIVALENCE_DATABASE - - // Ah well. Establish mediator objects for database signature links - AclIdentity aclIdentity(signature, path); - - uid_t user = process.uid(); - { - StLock _(mDatabaseLock); - find(aclIdentity, user); - find(clientIdentity, user); - } - - // if both links exist, we can decide this right now - if (aclIdentity && clientIdentity) { - if (aclIdentity.trustedName() == clientIdentity.trustedName()) { - secdebug("codesign", "app references match: pass"); - return true; - } else { - secdebug("codesign", "client/acl links exist but are unequal: fail"); - return false; - } - } - - // check for name equality - secdebug("codesign", "matching client %s against acl %s", - clientIdentity.name().c_str(), aclIdentity.name().c_str()); - if (aclIdentity.name() != clientIdentity.name()) { - secdebug("codesign", "name/path mismatch: fail"); - return false; - } - - // The names match - we have a possible update. - - // Take the UI lock now to serialize "update rushes". - LongtermStLock uiLocker(mUILock); - - // re-read the database in case some other thread beat us to the update - { - StLock _(mDatabaseLock); - find(aclIdentity, user); - find(clientIdentity, user); - } - if (aclIdentity && clientIdentity) { - if (aclIdentity.trustedName() == clientIdentity.trustedName()) { - secdebug("codesign", "app references match: pass (on the rematch)"); - return true; - } else { - secdebug("codesign", "client/acl links exist but are unequal: fail (on the rematch)"); - return false; - } - } - - // ask the user - QueryCodeCheck query; - query.inferHints(process); - if (!query(aclIdentity.path().c_str())) - { - secdebug("codesign", "user declined equivalence: cancel the access"); - CssmError::throwMe(CSSM_ERRCODE_USER_CANCELED); - } - - // take the database lock back for real - StLock _(mDatabaseLock); - - // user wants us to go ahead and establish trust (if possible) - if (aclIdentity) { - // acl is linked but new client: link the client to this application - makeLink(clientIdentity, aclIdentity.trustedName(), true, user); - mDb.flush(); - secdebug("codesign", "client %s linked to application %s: pass", - clientIdentity.path().c_str(), aclIdentity.trustedName().c_str()); - return true; - } - - if (clientIdentity) { // code link exists, acl link missing - // client is linked but ACL (hash) never seen: link the ACL to this app - makeLink(aclIdentity, clientIdentity.trustedName(), true, user); - mDb.flush(); - secdebug("codesign", "acl %s linked to client %s: pass", - aclIdentity.path().c_str(), clientIdentity.trustedName().c_str()); - return true; - } - - // the De Novo case: no links, must create everything - string ident = clientIdentity.name(); - makeLink(clientIdentity, ident, true, user); - makeLink(aclIdentity, ident, true, user); - mDb.flush(); - secdebug("codesign", "new linkages established: pass"); - return true; - -#else /* ignore Code Equivalence Database */ - - return false; - -#endif -} - - -// -// Debug dumping support -// -#if defined(DEBUGDUMP) - -void CodeSignatures::debugDump(const char *how) const -{ - using namespace Debug; - using namespace LowLevelMemoryUtilities; - if (!how) - how = "dump"; - CssmData key, value; - if (!mDb.first(key, value)) { - dump("CODE EQUIVALENTS DATABASE IS EMPTY (%s)\n", how); - } else { - dump("CODE EQUIVALENTS DATABASE DUMP (%s)\n", how); - do { - const char *header = key.interpretedAs(); - size_t headerLength = strlen(header) + 1; - dump("%s:", header); - dumpData(key.at(headerLength), key.length() - headerLength); - dump(" => "); - dumpData(value); - dump("\n"); - } while (mDb.next(key, value)); - dump("END DUMP\n"); - } -} - -void CodeSignatures::Identity::debugDump(const char *how) const -{ - using namespace Debug; - if (!how) - how = "dump"; - dump("IDENTITY (%s) path=%s", how, getPath().c_str()); - dump(" name=%s hash=", mName.empty() ? "(unset)" : mName.c_str()); - dumpData(getHash()); - dump("\n"); -} - -#endif //DEBUGDUMP