+/*
+ * Copyright (c) 2006,2011-2014 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@
+ */
+
+//
+// blob - generic extensible binary blob frame
+//
+// To define a new type of binary blob:
+// class MyBlob : public Blob<MyBlob, magic number> { ... }
+// Pick a unique magic number (32-bit). Blobs are understood to be a MyBlob
+// header possibly followed by more data as a contiguous memory area. Length
+// is overall (including the header), so a fixed-size blob would have length
+// sizeof(MyBlob). Both length and magic are stored in NBO.
+//
+// You are highly encouraged to follow these rules:
+// Store all integers in NBO, including offsets.
+// Use internal offsets to "point to" dynamically-sized elements past the
+// header (using the at<Type>(offset) method for access).
+// Don't use pointers in your blob.
+// If you follow those rules, your blobs will be fully relocatable, byte-order
+// independent, and generally spreading happiness around your code.
+//
+#ifndef _H_BLOB
+#define _H_BLOB
+
+#include <security_utilities/endian.h>
+#include <security_utilities/memutils.h>
+#include <security_utilities/errors.h>
+
+namespace Security {
+
+
+//
+// All blobs in memory have this form.
+// You can have polymorphic memory blobs (C style) using different magics numbers.
+//
+class BlobCore {
+public:
+ typedef uint32_t Offset;
+ typedef uint32_t Magic;
+
+ Magic magic() const { return mMagic; }
+ size_t length() const { return mLength; }
+
+ void initialize(Magic magic, size_t length = 0)
+ { mMagic = magic; mLength = (uint32_t)length; }
+
+ bool validateBlob(Magic magic, size_t minSize = 0, size_t maxSize = 0) const;
+
+ template <class T, class Offset>
+ T *at(Offset offset)
+ { return LowLevelMemoryUtilities::increment<T>(this, offset); }
+
+ template <class T, class Offset>
+ const T *at(Offset offset) const
+ { return LowLevelMemoryUtilities::increment<const T>(this, offset); }
+
+ template <class Offset1, class Offset2>
+ bool contains(Offset1 offset, Offset2 size) const
+ { return offset >= 0 && size_t(offset) >= sizeof(BlobCore) && (size_t(offset) + size) <= this->length(); }
+
+ template <class Base, class Offset>
+ bool contains(Base *ptr, Offset size) const
+ { return contains(LowLevelMemoryUtilities::difference(ptr, this), size); }
+
+ char *stringAt(Offset offset);
+ const char *stringAt(Offset offset) const;
+
+ void *data() { return this; }
+ const void *data() const { return this; }
+ void length(size_t size) { mLength = (uint32_t)size; }
+
+ BlobCore *clone() const
+ {
+ if (BlobCore *copy = (BlobCore *)malloc(this->length())) {
+ memcpy(copy, this, this->length());
+ return copy;
+ }
+ UnixError::throwMe(ENOMEM);
+ }
+
+ template <class BlobType>
+ bool is() const { return magic() == BlobType::typeMagic; }
+
+ static BlobCore *readBlob(std::FILE *file) { return readBlob(file, 0, 0, 0); }
+ static BlobCore *readBlob(int fd) { return readBlob(fd, 0, 0, 0); }
+
+protected:
+ static BlobCore *readBlob(std::FILE *file, uint32_t magic, size_t minSize, size_t maxSize); // streaming
+ static BlobCore *readBlob(int fd, uint32_t magic, size_t minSize, size_t maxSize); // streaming
+ static BlobCore *readBlob(int fd, size_t offset, uint32_t magic, size_t minSize, size_t maxSize); // pread(2)@offset
+
+protected:
+ Endian<uint32_t> mMagic;
+ Endian<uint32_t> mLength;
+};
+
+
+// basic validation helper
+inline bool BlobCore::validateBlob(Magic magic, size_t minSize /* = 0 */, size_t maxSize /* = 0 */) const
+{
+ uint32_t length = this->mLength;
+ if (magic && magic != this->mMagic) {
+ errno = EINVAL;
+ return false;
+ }
+ if (minSize ? (length < minSize) : (length < sizeof(BlobCore))) {
+ errno = EINVAL;
+ return false;
+ }
+ if (maxSize && length > maxSize) {
+ errno = ENOMEM;
+ return false;
+ }
+ return true;
+}
+
+
+//
+// Typed Blobs (BlobCores that know their real type and magic)
+//
+template <class BlobType, uint32_t _magic>
+class Blob: public BlobCore {
+public:
+ void initialize(size_t size = 0) { BlobCore::initialize(_magic, size); }
+
+ static const Magic typeMagic = _magic;
+
+ bool validateBlob() const
+ { return BlobCore::validateBlob(_magic, sizeof(BlobType)); }
+
+ bool validateBlob(size_t extLength) const
+ { return extLength >= sizeof(BlobType) && validateBlob() && mLength == extLength; }
+
+ static BlobType *specific(BlobCore *blob, bool unalloc = false)
+ {
+ if (BlobType *p = static_cast<BlobType *>(blob)) {
+ if (p->validateBlob())
+ return p;
+ if (unalloc)
+ ::free(p);
+ }
+ return NULL;
+ }
+
+ static const BlobType *specific(const BlobCore *blob)
+ {
+ const BlobType *p = static_cast<const BlobType *>(blob);
+ if (p && p->validateBlob())
+ return p;
+ return NULL;
+ }
+
+ BlobType *clone() const
+ { assert(validateBlob()); return specific(this->BlobCore::clone()); }
+
+ static BlobType *readBlob(int fd)
+ { return specific(BlobCore::readBlob(fd, _magic, sizeof(BlobType), 0), true); }
+
+ static BlobType *readBlob(int fd, size_t offset, size_t maxSize = 0)
+ { return specific(BlobCore::readBlob(fd, offset, _magic, sizeof(BlobType), maxSize), true); }
+
+ static BlobType *readBlob(std::FILE *file)
+ { return specific(BlobCore::readBlob(file, _magic, sizeof(BlobType), 0), true); }
+};
+
+
+//
+// A generic blob wrapped around arbitrary (flat) binary data.
+// This can be used to "regularize" plain binary data, so it can be handled
+// as a genuine Blob (e.g. for insertion into a SuperBlob).
+//
+class BlobWrapper : public Blob<BlobWrapper, 0xfade0b01> {
+public:
+ static BlobWrapper *alloc(size_t length, Magic magic = BlobWrapper::typeMagic);
+ static BlobWrapper *alloc(const void *data, size_t length, Magic magic = BlobWrapper::typeMagic);
+
+ unsigned char dataArea[0];
+
+ // override data/length to point to the payload (only)
+ void *data() { return dataArea; }
+ const void *data() const { return dataArea; }
+ size_t length() const { return BlobCore::length() - sizeof(BlobCore); }
+};
+
+
+} // Security
+
+#endif //_H_BLOB
projects / apple / security.git / blobdiff