Security-59306.11.20.tar.gz

[apple/security.git] / OSX / utilities / der_number.c

diff --git a/OSX/utilities/der_number.c b/OSX/utilities/der_number.c
new file mode 100644 (file)
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--- /dev/null
+++ b/OSX/utilities/der_number.c
@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2012,2014 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 <stdio.h>
+
+#include "utilities/SecCFRelease.h"
+#include "utilities/der_plist.h"
+#include "utilities/der_plist_internal.h"
+
+#include <corecrypto/ccder.h>
+#include <CoreFoundation/CoreFoundation.h>
+
+
+const uint8_t* der_decode_number(CFAllocatorRef allocator, CFOptionFlags mutability,
+                                 CFNumberRef* number, CFErrorRef *error,
+                                 const uint8_t* der, const uint8_t *der_end)
+{
+    if (NULL == der)
+        return NULL;
+
+    size_t payload_size = 0;
+    const uint8_t *payload = ccder_decode_tl(CCDER_INTEGER, &payload_size, der, der_end);
+
+    if (NULL == payload || (ssize_t) (der_end - payload) < (ssize_t) payload_size) {
+        SecCFDERCreateError(kSecDERErrorUnknownEncoding, CFSTR("Unknown number encoding"), NULL, error);
+        return NULL;
+    }
+    if (payload_size > sizeof(long long)) {
+        SecCFDERCreateError(kSecDERErrorUnsupportedNumberType, CFSTR("Number too large"), NULL, error);
+        return NULL;
+
+    }
+
+    long long value = 0;
+    
+    if (payload_size > 0) {
+        if ((*payload & 0x80) == 0x80)
+            value = -1; // Negative integers fill with 1s so we end up negative.
+        
+        const uint8_t* const payload_end = payload + payload_size;
+        
+        for (const uint8_t *payload_byte = payload;
+             payload_byte < payload_end;
+             ++payload_byte) {
+            value <<= 8;
+            value |= *payload_byte;
+        }
+    }
+
+    *number = CFNumberCreate(allocator, kCFNumberLongLongType, &value);
+    
+    if (*number == NULL) {
+        SecCFDERCreateError(kSecDERErrorAllocationFailure, CFSTR("Number allocation failed"), NULL, error);
+        return NULL;
+    }
+    
+    return payload + payload_size;
+}
+
+
+static inline uint8_t byte_of(size_t byteNumber, long long value)
+{
+    return value >> (8 * (byteNumber - 1));
+}
+
+static inline size_t bytes_when_encoded(long long value)
+{
+    size_t bytes_encoded = sizeof(long long);
+    
+    uint8_t first_byte = byte_of(bytes_encoded, value);
+    
+    // Skip initial 0xFFs or 0x00
+    if (first_byte == 0xFF || first_byte == 0x00) {
+        do {
+            --bytes_encoded;
+        } while (bytes_encoded > 1 && (byte_of(bytes_encoded, value) == first_byte));
+        
+        if ((first_byte & 0x80) != (byte_of(bytes_encoded, value) & 0x80))
+            bytes_encoded += 1;
+    }
+    
+    return bytes_encoded;
+}
+
+size_t der_sizeof_number(CFNumberRef data, CFErrorRef *error)
+{
+    long long value;
+    if (!CFNumberGetValue(data, kCFNumberLongLongType, &value))
+        return 0;
+    
+    return ccder_sizeof(CCDER_INTEGER, bytes_when_encoded(value));
+}
+
+uint8_t* der_encode_number(CFNumberRef number, CFErrorRef *error,
+                           const uint8_t *der, uint8_t *der_end)
+{
+    long long value;
+    if (!CFNumberGetValue(number, kCFNumberLongLongType, &value))
+        return NULL;
+    
+    size_t first_byte_to_include = bytes_when_encoded(value);
+    
+    if (!der_end || (ssize_t) (der_end - der) < (ssize_t) first_byte_to_include)
+        return NULL;
+
+    // Put the bytes we should include on the end.
+    for(size_t bytes_included = 0; bytes_included < first_byte_to_include; ++bytes_included)
+    {
+        --der_end;
+        *der_end = value & 0xFF;
+        value >>= 8;
+    }
+
+    return ccder_encode_tl(CCDER_INTEGER, first_byte_to_include, der, der_end);
+
+}