+/*
+ * Copyright (c) 2006-2014 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@
+ */
+
+//
+// codedirectory - format and operations for code signing "code directory" structures
+//
+#include "codedirectory.h"
+#include "csutilities.h"
+#include "CSCommonPriv.h"
+
+using namespace UnixPlusPlus;
+
+
+namespace Security {
+namespace CodeSigning {
+
+
+//
+// Highest understood special slot in this CodeDirectory.
+//
+CodeDirectory::SpecialSlot CodeDirectory::maxSpecialSlot() const
+{
+ SpecialSlot slot = this->nSpecialSlots;
+ if (slot > cdSlotMax)
+ slot = cdSlotMax;
+ return slot;
+}
+
+
+//
+// Canonical filesystem names for select slot numbers.
+// These are variously used for filenames, extended attribute names, etc.
+// to get some consistency in naming. These are for storing signing-related
+// data; they have no bearing on the actual hash slots in the CodeDirectory.
+//
+const char *CodeDirectory::canonicalSlotName(SpecialSlot slot)
+{
+ switch (slot) {
+ case cdRequirementsSlot:
+ return kSecCS_REQUIREMENTSFILE;
+ case cdResourceDirSlot:
+ return kSecCS_RESOURCEDIRFILE;
+ case cdCodeDirectorySlot:
+ return kSecCS_CODEDIRECTORYFILE;
+ case cdSignatureSlot:
+ return kSecCS_SIGNATUREFILE;
+ case cdApplicationSlot:
+ return kSecCS_APPLICATIONFILE;
+ case cdEntitlementSlot:
+ return kSecCS_ENTITLEMENTFILE;
+ default:
+ return NULL;
+ }
+}
+
+
+//
+// Canonical attributes of SpecialSlots.
+//
+unsigned CodeDirectory::slotAttributes(SpecialSlot slot)
+{
+ switch (slot) {
+ case cdRequirementsSlot:
+ return cdComponentIsBlob; // global
+ case cdCodeDirectorySlot:
+ return cdComponentPerArchitecture | cdComponentIsBlob;
+ case cdSignatureSlot:
+ return cdComponentPerArchitecture; // raw
+ case cdEntitlementSlot:
+ return cdComponentIsBlob; // global
+ case cdIdentificationSlot:
+ return cdComponentPerArchitecture; // raw
+ default:
+ return 0; // global, raw
+ }
+}
+
+
+//
+// Symbolic names for code directory special slots.
+// These are only used for debug output. They are not API-official.
+// Needs to be coordinated with the cd*Slot enumeration in codedirectory.h.
+//
+#if !defined(NDEBUG)
+const char * const CodeDirectory::debugSlotName[] = {
+ "codedirectory",
+ "info",
+ "requirements",
+ "resources",
+ "application",
+ "entitlement"
+};
+#endif //NDEBUG
+
+
+//
+// Check a CodeDirectory for basic integrity. This should ensure that the
+// version is understood by our code, and that the internal structure
+// (offsets etc.) is intact. In particular, it must make sure that no offsets
+// point outside the CodeDirectory.
+// Throws if the directory is corrupted or out of versioning bounds.
+// Returns if the version is usable (perhaps with degraded features due to
+// compatibility hacks).
+//
+// Note: There are some things we don't bother checking because they won't
+// cause crashes, and will just be flagged as nonsense later. For example,
+// a Bad Guy could overlap the identifier and hash fields, which is nonsense
+// but not dangerous.
+//
+void CodeDirectory::checkIntegrity() const
+{
+ // check version for support
+ if (!this->validateBlob())
+ MacOSError::throwMe(errSecCSSignatureInvalid); // busted
+ if (version > compatibilityLimit)
+ MacOSError::throwMe(errSecCSSignatureUnsupported); // too new - no clue
+ if (version < earliestVersion)
+ MacOSError::throwMe(errSecCSSignatureUnsupported); // too old - can't support
+ if (version > currentVersion)
+ secdebug("codedir", "%p version 0x%x newer than current 0x%x",
+ this, uint32_t(version), currentVersion);
+
+ // now check interior offsets for validity
+ if (!stringAt(identOffset))
+ MacOSError::throwMe(errSecCSSignatureFailed); // identifier out of blob range
+ if (version >= supportsTeamID && teamIDOffset != 0 && !stringAt(teamIDOffset))
+ MacOSError::throwMe(errSecCSSignatureFailed); // identifier out of blob range
+ if (!contains(hashOffset - int64_t(hashSize) * nSpecialSlots, hashSize * (int64_t(nSpecialSlots) + nCodeSlots)))
+ MacOSError::throwMe(errSecCSSignatureFailed); // hash array out of blob range
+ if (const Scatter *scatter = this->scatterVector()) {
+ // the optional scatter vector is terminated with an element having (count == 0)
+ unsigned int pagesConsumed = 0;
+ for (;; scatter++) {
+ if (!contains(scatter, sizeof(Scatter)))
+ MacOSError::throwMe(errSecCSSignatureFailed);
+ if (scatter->count == 0)
+ break;
+ pagesConsumed += scatter->count;
+ }
+ if (!contains((*this)[pagesConsumed-1], hashSize)) // referenced too many main hash slots
+ MacOSError::throwMe(errSecCSSignatureFailed);
+ }
+}
+
+
+//
+// Validate a slot against data in memory.
+//
+bool CodeDirectory::validateSlot(const void *data, size_t length, Slot slot) const
+{
+ secdebug("codedir", "%p validating slot %d", this, int(slot));
+ MakeHash<CodeDirectory> hasher(this);
+ Hashing::Byte digest[hasher->digestLength()];
+ generateHash(hasher, data, length, digest);
+ return memcmp(digest, (*this)[slot], hasher->digestLength()) == 0;
+}
+
+
+//
+// Validate a slot against the contents of an open file. At most 'length' bytes
+// will be read from the file.
+//
+bool CodeDirectory::validateSlot(FileDesc fd, size_t length, Slot slot) const
+{
+ MakeHash<CodeDirectory> hasher(this);
+ Hashing::Byte digest[hasher->digestLength()];
+ generateHash(hasher, fd, digest, length);
+ return memcmp(digest, (*this)[slot], hasher->digestLength()) == 0;
+}
+
+
+//
+// Check whether a particular slot is present.
+// Absense is indicated by either a zero hash, or by lying outside
+// the slot range.
+//
+bool CodeDirectory::slotIsPresent(Slot slot) const
+{
+ if (slot >= -Slot(nSpecialSlots) && slot < Slot(nCodeSlots)) {
+ const Hashing::Byte *digest = (*this)[slot];
+ for (unsigned n = 0; n < hashSize; n++)
+ if (digest[n])
+ return true; // non-zero digest => present
+ }
+ return false; // absent
+}
+
+
+//
+// Given a hash type code, create an appropriate subclass of DynamicHash
+// and return it. The caller owns the object and must delete it when done.
+// This function never returns NULL. It throws if the hashType is unsuupported,
+// or if there's an error creating the hasher.
+//
+DynamicHash *CodeDirectory::hashFor(HashAlgorithm hashType)
+{
+ CCDigestAlg alg;
+ switch (hashType) {
+ case kSecCodeSignatureHashSHA1: alg = kCCDigestSHA1; break;
+ case kSecCodeSignatureHashSHA256: alg = kCCDigestSHA256; break;
+ default:
+ MacOSError::throwMe(errSecCSSignatureUnsupported);
+ }
+ return new CCHashInstance(alg);
+}
+
+
+//
+// Hash the next limit bytes of a file and return the digest.
+// If the file is shorter, hash as much as you can.
+// Limit==0 means unlimited (to end of file).
+// Return how many bytes were actually hashed.
+// Throw on any errors.
+//
+size_t CodeDirectory::generateHash(DynamicHash *hasher, FileDesc fd, Hashing::Byte *digest, size_t limit)
+{
+ size_t size = hashFileData(fd, hasher, limit);
+ hasher->finish(digest);
+ return size;
+}
+
+
+//
+// Ditto, but hash a memory buffer instead.
+//
+size_t CodeDirectory::generateHash(DynamicHash *hasher, const void *data, size_t length, Hashing::Byte *digest)
+{
+ hasher->update(data, length);
+ hasher->finish(digest);
+ return length;
+}
+
+
+//
+// Turn a hash of canonical type into a hex string
+//
+std::string CodeDirectory::hexHash(const unsigned char *hash) const
+{
+ size_t size = this->hashSize;
+ char result[2*size+1];
+ for (unsigned n = 0; n < size; n++)
+ sprintf(result+2*n, "%02.2x", hash[n]);
+ return result;
+}
+
+
+//
+// Generate a screening code string from a (complete) CodeDirectory.
+// This can be used to make a lightweight pre-screening code from (just) a CodeDirectory.
+//
+std::string CodeDirectory::screeningCode() const
+{
+ if (slotIsPresent(-cdInfoSlot)) // has Info.plist
+ return "I" + hexHash((*this)[-cdInfoSlot]); // use Info.plist hash
+ if (pageSize == 0) // good-enough proxy for "not a Mach-O file"
+ return "M" + hexHash((*this)[0]); // use hash of main executable
+ return "N"; // no suitable screening code
+}
+
+
+} // CodeSigning
+} // Security
+
+
+//
+// Canonical text form for user-settable code directory flags.
+// Note: This table is actually exported from Security.framework.
+//
+const SecCodeDirectoryFlagTable kSecCodeDirectoryFlagTable[] = {
+ { "host", kSecCodeSignatureHost, true },
+ { "adhoc", kSecCodeSignatureAdhoc, false },
+ { "hard", kSecCodeSignatureForceHard, true },
+ { "kill", kSecCodeSignatureForceKill, true },
+ { "expires", kSecCodeSignatureForceExpiration, true },
+ { "restrict", kSecCodeSignatureRestrict, true },
+ { "enforcement", kSecCodeSignatureEnforcement, true },
+ { "library-validation", kSecCodeSignatureLibraryValidation, true },
+ { NULL }
+};
projects / apple / security.git / blobdiff