X-Git-Url: https://git.saurik.com/apple/security.git/blobdiff_plain/5c19dc3ae3bd8e40a9c028b0deddd50ff337692c..0d4552ce43ff8bf2e8666a9c5c44c3590eb117a8:/OSX/libsecurity_codesigning/lib/cdbuilder.cpp

diff --git a/OSX/libsecurity_codesigning/lib/cdbuilder.cpp b/OSX/libsecurity_codesigning/lib/cdbuilder.cpp
index 719a01b3..7fefc1c5 100644
--- a/OSX/libsecurity_codesigning/lib/cdbuilder.cpp
+++ b/OSX/libsecurity_codesigning/lib/cdbuilder.cpp
@@ -47,6 +47,11 @@ CodeDirectory::Builder::Builder(HashAlgorithm digestAlgorithm)
 	  mCodeSlots(0),
 	  mScatter(NULL),
 	  mScatterSize(0),
+	  mExecSegOffset(0),
+	  mExecSegLimit(0),
+	  mExecSegFlags(0),
+	  mGeneratePreEncryptHashes(false),
+	  mRuntimeVersion(0),
 	  mDir(NULL)
 {
 	mDigestLength = (uint32_t)MakeHash<Builder>(this)->digestLength();
@@ -75,13 +80,18 @@ void CodeDirectory::Builder::executable(string path,
 
 void CodeDirectory::Builder::reopen(string path, size_t offset, size_t length)
 {
-	assert(mExec);					// already called executable()
+	assert(opened());					// already called executable()
 	mExec.close();
 	mExec.open(path);
 	mExecOffset = offset;
 	mExecLength = length;
 }
 
+bool CodeDirectory::Builder::opened()
+{
+	return bool(mExec);
+}
+
 
 //
 // Set the source for one special slot
@@ -92,6 +102,7 @@ void CodeDirectory::Builder::specialSlot(SpecialSlot slot, CFDataRef data)
 	MakeHash<Builder> hash(this);
 	hash->update(CFDataGetBytePtr(data), CFDataGetLength(data));
 	hash->finish(specialSlot(slot));
+	mFilledSpecialSlots.insert(slot);
 	if (slot >= mSpecialSlots)
 		mSpecialSlots = slot;
 }
@@ -109,14 +120,20 @@ CodeDirectory::Scatter *CodeDirectory::Builder::scatter(unsigned count)
 	return mScatter;
 }
 
-// This calculates the fixed size of the code directory
-// Because of <rdar://problem/16102695>, if the team ID
-// field is not used, we leave out the team ID offset
-// as well, to keep cd hashes consistent between
-// versions.
-const size_t CodeDirectory::Builder::fixedSize(const uint32_t version)
+//
+// Keep the allocated size of the (static) CodeDirectory consistent with
+// the version chosen. We dynamically picked the least-needed version
+// to provide stability of virtual signatures.
+//
+size_t CodeDirectory::Builder::fixedSize(const uint32_t version)
 {
 	size_t cdSize = sizeof(CodeDirectory);
+	if (version < supportsPreEncrypt)
+		cdSize -= sizeof(mDir->runtime) + sizeof(mDir->preEncryptOffset);
+	if (version < supportsExecSegment)
+		cdSize -= sizeof(mDir->execSegBase) + sizeof(mDir->execSegLimit) + sizeof(mDir->execSegFlags);
+	if (version < supportsCodeLimit64)
+		cdSize -= sizeof(mDir->spare3) + sizeof(mDir->codeLimit64);
 	if (version < supportsTeamID)
 		cdSize -= sizeof(mDir->teamIDOffset);
 
@@ -149,6 +166,11 @@ size_t CodeDirectory::Builder::size(const uint32_t version)
 	if (mTeamID.size())
 		offset += mTeamID.size() + 1;	// size of teamID (with null byte)
 	offset += (mCodeSlots + mSpecialSlots) * mDigestLength; // hash vector
+
+	if (mGeneratePreEncryptHashes || !mPreservedPreEncryptHashMap.empty()) {
+		offset += mCodeSlots * mDigestLength;
+	}
+
 	if (offset <= offset0)
 		UnixError::throwMe(ENOEXEC);
 
@@ -179,26 +201,37 @@ CodeDirectory *CodeDirectory::Builder::build()
 	size_t teamIDLength = mTeamID.size() + 1;
 	
 	// Determine the version
-	if (mTeamID.size()) {
+	if (mGeneratePreEncryptHashes || !mPreservedPreEncryptHashMap.empty() || mRuntimeVersion) {
 		version = currentVersion;
+	} else if (mExecSegLimit > 0) {
+		version = supportsExecSegment;
+	} else if (mExecLength > UINT32_MAX) {
+		version = supportsCodeLimit64;
+	} else if (mTeamID.size()) {
+		version = supportsTeamID;
 	} else {
 		version = supportsScatter;
 	}
 	
+	if (mCodeSlots > UINT32_MAX)	// (still limited to 32 bits)
+		MacOSError::throwMe(errSecCSTooBig);
+	
 	size_t total = size(version);
 	if (!(mDir = (CodeDirectory *)calloc(1, total)))	// initialize to zero
 		UnixError::throwMe(ENOMEM);
-	
-	if (mExecLength > UINT32_MAX)
-		MacOSError::throwMe(errSecCSTooBig);
-	
+
 	// fill header
 	mDir->initialize(total);
 	mDir->version = version;
 	mDir->flags = mFlags;
 	mDir->nSpecialSlots = (uint32_t)mSpecialSlots;
 	mDir->nCodeSlots = (uint32_t)mCodeSlots;
-	mDir->codeLimit = (uint32_t)mExecLength;
+	if (mExecLength > UINT32_MAX) {
+		mDir->codeLimit = UINT32_MAX;
+		mDir->codeLimit64 = mExecLength;
+	} else {
+		mDir->codeLimit = uint32_t(mExecLength);
+	}
 	mDir->hashType = mHashType;
 	mDir->platform = mPlatform;
 	mDir->hashSize = mDigestLength;
@@ -211,6 +244,11 @@ CodeDirectory *CodeDirectory::Builder::build()
 	} else
 		mDir->pageSize = 0;	// means infinite page size
 
+	mDir->execSegBase = mExecSegOffset;
+	mDir->execSegLimit = mExecSegLimit;
+	mDir->execSegFlags = mExecSegFlags;
+	mDir->runtime = mRuntimeVersion;
+
 	// locate and fill flex fields
 	size_t offset = fixedSize(mDir->version);
 	
@@ -229,26 +267,53 @@ CodeDirectory *CodeDirectory::Builder::build()
 		memcpy(mDir->teamID(), mTeamID.c_str(), teamIDLength);
 		offset += teamIDLength;
 	}
+
 	// (add new flexibly-allocated fields here)
 
+	/* Pre-encrypt hashes come before normal hashes, so that the kernel can free
+	 * the normal, potentially post-encrypt hashes away easily. */
+	if (mGeneratePreEncryptHashes || !mPreservedPreEncryptHashMap.empty()) {
+		mDir->preEncryptOffset = (uint32_t)offset;
+		offset += mCodeSlots * mDigestLength;
+	}
+
 	mDir->hashOffset = (uint32_t)(offset + mSpecialSlots * mDigestLength);
 	offset += (mSpecialSlots + mCodeSlots) * mDigestLength;
+
 	assert(offset == total);	// matches allocated size
+
+	(void)offset;
 	
 	// fill special slots
-	memset((*mDir)[(int)-mSpecialSlots], 0, mDigestLength * mSpecialSlots);
+	memset(mDir->getSlotMutable((int)-mSpecialSlots, false), 0, mDigestLength * mSpecialSlots);
 	for (size_t slot = 1; slot <= mSpecialSlots; ++slot)
-		memcpy((*mDir)[(int)-slot], specialSlot((SpecialSlot)slot), mDigestLength);
+		memcpy(mDir->getSlotMutable((int)-slot, false), specialSlot((SpecialSlot)slot), mDigestLength);
 	
 	// fill code slots
 	mExec.seek(mExecOffset);
 	size_t remaining = mExecLength;
 	for (unsigned int slot = 0; slot < mCodeSlots; ++slot) {
-		size_t thisPage = min(mPageSize, remaining);
+		size_t thisPage = remaining;
+		if (mPageSize)
+			thisPage = min(thisPage, mPageSize);
 		MakeHash<Builder> hasher(this);
-		generateHash(hasher, mExec, (*mDir)[slot], thisPage);
+		generateHash(hasher, mExec, mDir->getSlotMutable(slot, false), thisPage);
+		if (mGeneratePreEncryptHashes && mPreservedPreEncryptHashMap.empty()) {
+			memcpy(mDir->getSlotMutable(slot, true), mDir->getSlot(slot, false),
+				   mDir->hashSize);
+		}
 		remaining -= thisPage;
 	}
+	assert(remaining == 0);
+
+	PreEncryptHashMap::iterator preEncrypt =
+		mPreservedPreEncryptHashMap.find(mHashType);
+	if (preEncrypt != mPreservedPreEncryptHashMap.end()) {
+		memcpy(mDir->getSlotMutable(0, true),
+			   CFDataGetBytePtr(preEncrypt->second),
+			   mCodeSlots * mDigestLength);
+		mPreservedPreEncryptHashMap.erase(preEncrypt->first); // Releases the CFData memory.
+	}
 	
 	// all done. Pass ownership to caller
 	return mDir;