+/*
+ * Copyright (c) 2014 Apple Inc. All Rights Reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_LICENSE_HEADER_END@
+ */
+#include "opaquewhitelist.h"
+#include "csutilities.h"
+#include "StaticCode.h"
+#include <CoreFoundation/CoreFoundation.h>
+#include <Security/SecCodePriv.h>
+#include <Security/SecCodeSigner.h>
+#include <Security/SecStaticCode.h>
+#include <security_utilities/cfutilities.h>
+#include <security_utilities/cfmunge.h>
+#include <CoreFoundation/CFBundlePriv.h>
+
+namespace Security {
+namespace CodeSigning {
+
+using namespace SQLite;
+
+
+static void traceHash(MessageTrace &trace, const char *key, CFDataRef hash);
+static void attachOpaque(SecStaticCodeRef code);
+
+
+//
+// Open the database
+//
+OpaqueWhitelist::OpaqueWhitelist(const char *path, int flags)
+ : SQLite::Database(path ? path : opaqueDatabase, flags)
+{
+ SQLite::Statement createConditions(*this,
+ "CREATE TABLE IF NOT EXISTS conditions ("
+ " label text,"
+ " weight real not null unique,"
+ " source text,"
+ " identifier text,"
+ " version text,"
+ " conditions text not null);"
+ );
+ createConditions.execute();
+
+}
+
+OpaqueWhitelist::~OpaqueWhitelist()
+{ /* virtual */ }
+
+
+//
+// Check if a code object is whitelisted
+//
+bool OpaqueWhitelist::contains(SecStaticCodeRef codeRef, OSStatus reason, bool trace)
+{
+ // make our own copy of the code object, so we can poke at it without disturbing the original
+ SecPointer<SecStaticCode> code = new SecStaticCode(SecStaticCode::requiredStatic(codeRef)->diskRep());
+
+ CFCopyRef<CFDataRef> current = code->cdHash(); // current cdhash
+ CFDataRef opaque = NULL; // holds computed opaque cdhash
+ bool match = false; // holds final result
+
+ if (!current)
+ return false; // unsigned
+
+ // collect auxiliary information for trace
+ CFRef<CFDictionaryRef> info;
+ std::string team = "";
+ CFStringRef cfVersion = NULL, cfShortVersion = NULL, cfExecutable = NULL;
+ if (errSecSuccess == SecCodeCopySigningInformation(code->handle(false), kSecCSSigningInformation, &info.aref())) {
+ if (CFStringRef cfTeam = CFStringRef(CFDictionaryGetValue(info, kSecCodeInfoTeamIdentifier)))
+ team = cfString(cfTeam);
+ if (CFDictionaryRef infoPlist = CFDictionaryRef(CFDictionaryGetValue(info, kSecCodeInfoPList))) {
+ if (CFTypeRef version = CFDictionaryGetValue(infoPlist, kCFBundleVersionKey))
+ if (CFGetTypeID(version) == CFStringGetTypeID())
+ cfVersion = CFStringRef(version);
+ if (CFTypeRef shortVersion = CFDictionaryGetValue(infoPlist, _kCFBundleShortVersionStringKey))
+ if (CFGetTypeID(shortVersion) == CFStringGetTypeID())
+ cfShortVersion = CFStringRef(shortVersion);
+ if (CFTypeRef executable = CFDictionaryGetValue(infoPlist, kCFBundleExecutableKey))
+ if (CFGetTypeID(executable) == CFStringGetTypeID())
+ cfExecutable = CFStringRef(executable);
+ }
+ }
+
+ // compute and attach opaque signature
+ attachOpaque(code->handle(false));
+ opaque = code->cdHash();
+
+ // lookup current cdhash in whitelist
+ SQLite::Statement lookup(*this, "SELECT opaque FROM whitelist WHERE current=:current");
+ lookup.bind(":current") = current.get();
+ while (lookup.nextRow()) {
+ CFRef<CFDataRef> expected = lookup[0].data();
+ if (CFEqual(opaque, expected)) {
+ match = true; // actual opaque cdhash matches expected
+ break;
+ }
+ }
+
+ if (trace) {
+ // send a trace indicating the result
+ MessageTrace trace("com.apple.security.assessment.whitelist2", code->identifier().c_str());
+ traceHash(trace, "signature2", current);
+ traceHash(trace, "signature3", opaque);
+ trace.add("result", match ? "pass" : "fail");
+ trace.add("reason", "%d", reason);
+ if (!team.empty())
+ trace.add("teamid", "%s", team.c_str());
+ if (cfVersion)
+ trace.add("version", "%s", cfString(cfVersion).c_str());
+ if (cfShortVersion)
+ trace.add("version2", "%s", cfString(cfShortVersion).c_str());
+ if (cfExecutable)
+ trace.add("execname", "%s", cfString(cfExecutable).c_str());
+ trace.send("");
+ }
+
+ return match;
+}
+
+
+//
+// Obtain special validation conditions for a static code, based on database configuration.
+//
+CFDictionaryRef OpaqueWhitelist::validationConditionsFor(SecStaticCodeRef code)
+{
+ // figure out which team key to use
+ std::string team = "UNKNOWN";
+ CFStringRef cfId = NULL;
+ CFStringRef cfVersion = NULL;
+ CFRef<CFDictionaryRef> info; // holds lifetimes for the above
+ if (errSecSuccess == SecCodeCopySigningInformation(code, kSecCSSigningInformation, &info.aref())) {
+ if (CFStringRef cfTeam = CFStringRef(CFDictionaryGetValue(info, kSecCodeInfoTeamIdentifier)))
+ team = cfString(cfTeam);
+ cfId = CFStringRef(CFDictionaryGetValue(info, kSecCodeInfoIdentifier));
+ if (CFDictionaryRef infoPlist = CFDictionaryRef(CFDictionaryGetValue(info, kSecCodeInfoPList)))
+ if (CFTypeRef version = CFDictionaryGetValue(infoPlist, _kCFBundleShortVersionStringKey))
+ if (CFGetTypeID(version) == CFStringGetTypeID())
+ cfVersion = CFStringRef(version);
+ }
+ if (cfId == NULL) // unsigned; punt
+ return NULL;
+
+ // find the highest weight matching condition. We perform no merging and the heaviest rule wins
+ SQLite::Statement matches(*this,
+ "SELECT conditions FROM conditions"
+ " WHERE (source = :source or source IS NULL)"
+ " AND (identifier = :identifier or identifier is NULL)"
+ " AND ((:version IS NULL AND version IS NULL) OR (version = :version OR version IS NULL))"
+ " ORDER BY weight DESC"
+ " LIMIT 1"
+ );
+ matches.bind(":source") = team;
+ matches.bind(":identifier") = cfString(cfId);
+ if (cfVersion)
+ matches.bind(":version") = cfString(cfVersion);
+ if (matches.nextRow()) {
+ CFTemp<CFDictionaryRef> conditions((const char*)matches[0]);
+ return conditions.yield();
+ }
+ // no matches
+ return NULL;
+}
+
+
+//
+// Convert a SHA1 hash to hex and add to a trace
+//
+static void traceHash(MessageTrace &trace, const char *key, CFDataRef hash)
+{
+ if (CFDataGetLength(hash) != sizeof(SHA1::Digest)) {
+ trace.add(key, "(unknown format)");
+ } else {
+ const UInt8 *bytes = CFDataGetBytePtr(hash);
+ char s[2 * SHA1::digestLength + 1];
+ for (unsigned n = 0; n < SHA1::digestLength; n++)
+ sprintf(&s[2*n], "%2.2x", bytes[n]);
+ trace.add(key, s);
+ }
+}
+
+
+//
+// Add a code object to the whitelist
+//
+void OpaqueWhitelist::add(SecStaticCodeRef codeRef)
+{
+ // make our own copy of the code object
+ SecPointer<SecStaticCode> code = new SecStaticCode(SecStaticCode::requiredStatic(codeRef)->diskRep());
+
+ CFCopyRef<CFDataRef> current = code->cdHash();
+ attachOpaque(code->handle(false)); // compute and attach an opaque signature
+ CFDataRef opaque = code->cdHash();
+
+ SQLite::Statement insert(*this, "INSERT OR REPLACE INTO whitelist (current,opaque) VALUES (:current, :opaque)");
+ insert.bind(":current") = current.get();
+ insert.bind(":opaque") = opaque;
+ insert.execute();
+}
+
+
+//
+// Generate and attach an ad-hoc opaque signature
+//
+static void attachOpaque(SecStaticCodeRef code)
+{
+ CFTemp<CFDictionaryRef> rules("{" // same resource rules as used for collection
+ "rules={"
+ "'^.*' = #T"
+ "'^Info\\.plist$' = {omit=#T,weight=10}"
+ "},rules2={"
+ "'^(Frameworks|SharedFrameworks|Plugins|Plug-ins|XPCServices|Helpers|MacOS)/' = {nested=#T, weight=0}"
+ "'^.*' = #T"
+ "'^Info\\.plist$' = {omit=#T,weight=10}"
+ "'^[^/]+$' = {top=#T, weight=0}"
+ "}"
+ "}");
+
+ CFRef<CFDataRef> signature = CFDataCreateMutable(NULL, 0);
+ CFTemp<CFDictionaryRef> arguments("{%O=%O, %O=#N, %O=%O}",
+ kSecCodeSignerDetached, signature.get(),
+ kSecCodeSignerIdentity, /* kCFNull, */
+ kSecCodeSignerResourceRules, rules.get());
+ CFRef<SecCodeSignerRef> signer;
+ SecCSFlags flags = kSecCSSignOpaque | kSecCSSignNoV1 | kSecCSSignBundleRoot;
+ MacOSError::check(SecCodeSignerCreate(arguments, flags, &signer.aref()));
+ MacOSError::check(SecCodeSignerAddSignature(signer, code, kSecCSDefaultFlags));
+ MacOSError::check(SecCodeSetDetachedSignature(code, signature, kSecCSDefaultFlags));
+}
+
+
+} // end namespace CodeSigning
+} // end namespace Security
projects / apple / security.git / commitdiff
