X-Git-Url: https://git.saurik.com/apple/security.git/blobdiff_plain/c38e3ce98599a410a47dc10253faa4d5830f13b2..427c49bcad63d042b29ada2ac27e3dfc4845c779:/sec/Security/SecOTRMath.c?ds=sidebyside

diff --git a/sec/Security/SecOTRMath.c b/sec/Security/SecOTRMath.c
new file mode 100644
index 00000000..65615ffc
--- /dev/null
+++ b/sec/Security/SecOTRMath.c
@@ -0,0 +1,186 @@
+//
+//  OTRMath.c
+//  libsecurity_libSecOTR
+//
+//  Created by Mitch Adler on 1/28/11.
+//  Copyright 2011 Apple Inc. All rights reserved.
+//
+
+#include "SecOTRMath.h"
+#include "SecOTRMathPrivate.h"
+
+#include "SecOTRPacketData.h"
+
+#include <AssertMacros.h>
+
+#include <pthread.h>
+
+#include <Security/SecRandom.h>
+
+#include <corecrypto/ccsha2.h>
+#include <corecrypto/cczp.h>
+
+#include <limits.h>
+
+static inline
+void cczp_init_from_bytes(cc_size n, cczp_t zp, size_t pSize, const void *p, size_t rSize, const void* r)
+{
+    CCZP_N(zp) = n;
+    zp.zp->mod_prime = cczp_mod;
+    ccn_read_uint(n, CCZP_PRIME(zp), pSize, p);
+    ccn_read_uint(n+1, CCZP_RECIP(zp), rSize, r);
+
+}
+
+static pthread_once_t   kOTRImportGroupData = PTHREAD_ONCE_INIT;
+
+static cc_unit sOTRGenerator[kOTRDHGroupUnits];
+static cczp_decl_n(kOTRDHGroupUnits, sOTRGroup_zp);
+
+static void setupGroupValues()
+{
+    __Check( kExponentiationUnits == kOTRDHGroupUnits );
+
+    cczp_init_from_bytes(kOTRDHGroupUnits, sOTRGroup_zp,
+                         sizeof(kOTRDHGroup), kOTRDHGroup,
+                         sizeof(kOTRDHGroup_Recip), kOTRDHGroup_Recip);
+    
+    ccn_seti(kOTRDHGroupUnits, sOTRGenerator, kOTRGeneratorValue);
+}
+
+void OTRExponentiate(cc_unit* res, const cc_unit* base, const cc_unit* exponent)
+{
+    pthread_once(&kOTRImportGroupData, setupGroupValues);
+    
+    cczp_power(sOTRGroup_zp, res, base, exponent);
+}
+
+void OTRGroupExponentiate(cc_unit* res, const cc_unit* exponent)
+{
+    pthread_once(&kOTRImportGroupData, setupGroupValues);
+
+    OTRExponentiate(res, sOTRGenerator, exponent);
+}
+
+//
+// Random Number Generation
+//
+
+OSStatus GetRandomBytesInLSBs(size_t bytesOfRandomness, size_t n, cc_unit* place)
+{
+    OSStatus result = errSecParam;
+    require(bytesOfRandomness * 8 <= ccn_bitsof_n(n), fail);
+    {
+        uint8_t randomBytes[bytesOfRandomness];
+        
+        result = SecRandomCopyBytes(kSecRandomDefault, sizeof(randomBytes), randomBytes);
+        
+        require_noerr(result, fail);
+        
+        ccn_read_uint(n, place, sizeof(randomBytes), randomBytes);
+        
+        bzero(randomBytes, bytesOfRandomness);
+    }
+fail:
+    return result;
+}
+
+OSStatus FillWithRandomBytes(size_t n, cc_unit* place)
+{
+    return GetRandomBytesInLSBs(ccn_sizeof(n), n, place);
+}
+
+
+static const uint8_t kIVZero[16] = { };
+
+static void AES_CTR_Transform(size_t keySize, const uint8_t* key,
+                       const uint8_t iv[16],
+                       size_t howMuch, const uint8_t* from, uint8_t* to)
+{
+    const struct ccmode_ctr* ctr_encrypt = ccaes_ctr_crypt_mode();
+    ccctr_ctx_decl(ctr_encrypt->size, ctr_ctx);
+    ctr_encrypt->init(ctr_encrypt, ctr_ctx, keySize, key, iv);
+    
+    ctr_encrypt->ctr(ctr_ctx, howMuch, from, to);
+}
+
+void AES_CTR_HighHalf_Transform(size_t keySize, const uint8_t* key,
+                                uint64_t highHalf,
+                                size_t howMuch, const uint8_t* from, uint8_t* to)
+{
+    uint8_t iv[16] = { highHalf >> 56, highHalf >> 48, highHalf >> 40, highHalf >> 32,
+                       highHalf >> 24, highHalf >> 16, highHalf >> 8 , highHalf >> 0,
+                                    0,              0,             0,              0,
+                                    0,              0,             0,              0 };
+    AES_CTR_Transform(keySize, key, iv, howMuch, from, to);
+}
+
+void AES_CTR_IV0_Transform(size_t keySize, const uint8_t* key,
+                           size_t howMuch, const uint8_t* from, uint8_t* to)
+{
+    AES_CTR_Transform(keySize, key, kIVZero, howMuch, from, to);
+}
+
+
+//
+// Key Derivation
+//
+
+static void HashMPIWithPrefix(uint8_t byte, cc_size sN, const cc_unit* s, uint8_t* buffer)
+{
+    CFMutableDataRef dataToHash = CFDataCreateMutable(kCFAllocatorDefault, 0);
+    CFDataAppendBytes(dataToHash, &byte, 1);
+    
+    AppendMPI(dataToHash, sN, s);
+    
+    uint8_t *bytesToHash = CFDataGetMutableBytePtr(dataToHash);
+    CFIndex  amountToHash = CFDataGetLength(dataToHash);
+    
+    /* 64 bits cast: amountToHash is the size of an identity +1 , which is currently hardcoded and never more than 2^32 bytes */
+    assert((unsigned long)amountToHash<UINT32_MAX); /* Debug check, Correct as long as CFIndex is a signed long and CC_LONG is a uint32_t */
+
+    (void) CC_SHA256(bytesToHash, (CC_LONG)amountToHash, buffer);
+    
+    bzero(bytesToHash, (size_t)amountToHash);
+    CFReleaseNull(dataToHash);
+}
+
+void DeriveOTR256BitsFromS(KeyType whichKey, cc_size sN, const cc_unit* s, size_t keySize, uint8_t* key)
+{
+    HashMPIWithPrefix(whichKey, sN, s, key);
+}
+
+void DeriveOTR128BitPairFromS(KeyType whichKey, size_t sSize, const cc_unit* s,
+                              size_t firstKeySize, uint8_t* firstKey,
+                              size_t secondKeySize, uint8_t* secondKey)
+{
+    uint8_t hashBuffer[CCSHA256_OUTPUT_SIZE];
+    
+    HashMPIWithPrefix(whichKey, sSize, s, hashBuffer);
+    
+    if (firstKey) {
+        firstKeySize = firstKeySize > CCSHA256_OUTPUT_SIZE/2 ? CCSHA256_OUTPUT_SIZE/2 : firstKeySize;
+        memcpy(firstKey, hashBuffer, firstKeySize);
+    }
+    if (secondKey) {
+        secondKeySize = secondKeySize > CCSHA256_OUTPUT_SIZE/2 ? CCSHA256_OUTPUT_SIZE/2 : secondKeySize;
+        memcpy(secondKey, hashBuffer, secondKeySize);
+    }
+    
+    bzero(hashBuffer, CCSHA256_OUTPUT_SIZE);
+
+}
+
+void DeriveOTR64BitsFromS(KeyType whichKey, size_t sn, const cc_unit* s,
+                          size_t topKeySize, uint8_t* topKey)
+{
+    uint8_t hashBuffer[CCSHA256_OUTPUT_SIZE];
+    
+    HashMPIWithPrefix(whichKey, sn, s, hashBuffer);
+    
+    topKeySize = topKeySize > CCSHA256_OUTPUT_SIZE/2 ? CCSHA256_OUTPUT_SIZE/2 : topKeySize;
+    memcpy(topKey, hashBuffer, topKeySize);
+    
+    bzero(hashBuffer, CCSHA256_OUTPUT_SIZE);
+}
+