X-Git-Url: https://git.saurik.com/apple/security.git/blobdiff_plain/72a12576750f52947eb043106ba5c12c0d07decf..b1ab9ed8d0e0f1c3b66d7daa8fd5564444c56195:/libsecurity_codesigning/lib/cfmdiskrep.cpp

diff --git a/libsecurity_codesigning/lib/cfmdiskrep.cpp b/libsecurity_codesigning/lib/cfmdiskrep.cpp
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+/*
+ * Copyright (c) 2007 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@
+ */
+ 
+//
+// cfmdiskrep - single-file CFM (PEF) executable disk representation
+//
+#include "cfmdiskrep.h"
+#include <cstring>
+
+
+namespace Security {
+namespace CodeSigning {
+
+using namespace UnixPlusPlus;
+
+
+//
+// Everything's lazy in here
+//
+CFMDiskRep::CFMDiskRep(const char *path)
+	: SingleDiskRep(path), mTriedRead(false)
+{
+	CODESIGN_DISKREP_CREATE_CFM(this, (char*)path);
+}
+
+CFMDiskRep::~CFMDiskRep()
+{
+	if (mTriedRead)
+		delete mSigningData;
+}
+
+
+//
+// CFM filter heuristic.
+// We look for the PEF header within the first scanLength bytes
+// of the file's data fork, at certain alignment boundaries (probably
+// conservative).
+//
+bool CFMDiskRep::candidate(FileDesc &fd)
+{
+	static const char magicMarker[] = "Joy!peffpwpc";
+	static const size_t magicLength = 12;
+	static const size_t scanLength = 128;
+	static const size_t scanAlignment = 4;
+	
+	char marker[scanLength];
+	if (fd.read(marker, scanLength, 0) == scanLength)
+		for (size_t p = 0; p <= scanLength - magicLength; p += scanAlignment)
+			if (!memcmp(marker+p, magicMarker, magicLength))
+				return true;
+	return false;
+}
+
+
+//
+// Extract and return a component by slot number.
+// If we have a Mach-O binary, use embedded components.
+// Otherwise, look for and return the extended attribute, if any.
+//
+CFDataRef CFMDiskRep::component(CodeDirectory::SpecialSlot slot)
+{
+	if (!mTriedRead)
+		readSigningData();
+	if (mSigningData)
+		return mSigningData->component(slot);
+	else
+		return NULL;
+}
+
+
+//
+// The signing limit is the start of the signature if present,
+// or the end of the file otherwise.
+//
+size_t CFMDiskRep::signingLimit()
+{
+	readSigningData();
+	if (mSigningData)
+		return mSigningOffset;
+	else
+		return fd().fileSize();
+}
+
+
+//
+// Various other aspects of our DiskRep personality.
+//
+string CFMDiskRep::format()
+{
+	return "CFM/PEF binary";
+}
+
+
+//
+// Discard cached information
+//
+void CFMDiskRep::flush()
+{
+	mTriedRead = false;
+	::free(mSigningData);
+}
+
+
+//
+// In Mac OS X, a CFM binary must always be managed by the LaunchCFMApp
+// system tool. Thus, we recommend that this be required as a host.
+//
+static const uint8_t cfm_ireqs[] = {	// host => anchor apple and identifier com.apple.LaunchCFMApp
+	0xfa, 0xde, 0x0c, 0x01, 0x00, 0x00, 0x00, 0x48, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x01,
+	0x00, 0x00, 0x00, 0x14, 0xfa, 0xde, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x34, 0x00, 0x00, 0x00, 0x01,
+	0x00, 0x00, 0x00, 0x06, 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x16,
+	0x63, 0x6f, 0x6d, 0x2e, 0x61, 0x70, 0x70, 0x6c, 0x65, 0x2e, 0x4c, 0x61, 0x75, 0x6e, 0x63, 0x68,
+	0x43, 0x46, 0x4d, 0x41, 0x70, 0x70, 0x00, 0x00,
+};
+
+const Requirements *CFMDiskRep::defaultRequirements(const Architecture *, const SigningContext &)
+{
+	return ((const Requirements *)cfm_ireqs)->clone();	// need to pass ownership
+}
+
+
+//
+// Default to system-paged signing
+//
+size_t CFMDiskRep::pageSize(const SigningContext &)
+{
+	return segmentedPageSize;
+}
+
+
+//
+// Locate, read, and cache embedded signing data from the CFM binary.
+//
+void CFMDiskRep::readSigningData()
+{
+	if (!mTriedRead) {				// try it once
+		mSigningData = NULL;		// preset failure
+		mTriedRead = true;			// we've tried (and perhaps failed)
+		
+		FileDesc &fd = this->fd();
+		fd.seek(fd.fileSize() - sizeof(Sentinel));
+		Sentinel sentinel;
+		if (fd.read(&sentinel, sizeof(sentinel), fd.fileSize() - sizeof(Sentinel)) == sizeof(Sentinel))
+			if (sentinel.magic == EmbeddedSignatureBlob::typeMagic) {
+				mSigningOffset = sentinel.offset;
+				if ((mSigningData = EmbeddedSignatureBlob::readBlob(fd, mSigningOffset)))
+					secdebug("cfmrep", "%zd signing bytes in %d blob(s) from %s(CFM)",
+						mSigningData->length(), mSigningData->count(),
+						mainExecutablePath().c_str());
+				else
+					secdebug("cfmrep", "failed to read signing bytes from %s(CFM)",
+						mainExecutablePath().c_str());
+			}
+	}
+}
+
+
+//
+// CFMDiskRep::Writers
+//
+DiskRep::Writer *CFMDiskRep::writer()
+{
+	return new Writer(this);
+}
+
+CFMDiskRep::Writer::~Writer()
+{
+	delete mSigningData;
+}
+
+
+//
+// Write a component.
+// Note that this isn't concerned with Mach-O writing; this is handled at
+// a much higher level. If we're called, it's extended attribute time.
+//
+void CFMDiskRep::Writer::component(CodeDirectory::SpecialSlot slot, CFDataRef data)
+{
+	EmbeddedSignatureBlob::Maker::component(slot, data);
+}
+
+
+//
+// Append the superblob we built to the CFM binary.
+// Note: Aligning the signing blob to a 16-byte boundary is not strictly necessary,
+// but it's what the Mach-O case does, and it probably improves performance a bit.
+//
+void CFMDiskRep::Writer::flush()
+{
+	delete mSigningData;			// ditch previous blob just in case
+	mSigningData = Maker::make();	// assemble new signature SuperBlob
+	size_t start = LowLevelMemoryUtilities::alignUp(rep->signingLimit(), 16);
+	Sentinel sentinel;
+	sentinel.magic = EmbeddedSignatureBlob::typeMagic;
+	sentinel.offset = start;
+	AutoFileDesc fd(rep->path(), O_RDWR);
+	fd.seek(start);
+	fd.writeAll(mSigningData, mSigningData->length());
+	fd.writeAll(&sentinel, sizeof(sentinel));
+}
+
+
+} // end namespace CodeSigning
+} // end namespace Security