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[apple/security.git] / Security / libsecurity_cryptkit / lib / byteRep.c
diff --git a/Security/libsecurity_cryptkit/lib/byteRep.c b/Security/libsecurity_cryptkit/lib/byteRep.c
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+/* Copyright (c) 1998,2011,2014 Apple Inc.  All Rights Reserved.
+ *
+ * NOTICE: USE OF THE MATERIALS ACCOMPANYING THIS NOTICE IS SUBJECT
+ * TO THE TERMS OF THE SIGNED "FAST ELLIPTIC ENCRYPTION (FEE) REFERENCE
+ * SOURCE CODE EVALUATION AGREEMENT" BETWEEN APPLE, INC. AND THE
+ * ORIGINAL LICENSEE THAT OBTAINED THESE MATERIALS FROM APPLE,
+ * INC.  ANY USE OF THESE MATERIALS NOT PERMITTED BY SUCH AGREEMENT WILL
+ * EXPOSE YOU TO LIABILITY.
+ ***************************************************************************
+ *
+ * byteRep.c -  FEE portable byte representation support
+ *
+ * Revision History
+ * ----------------
+ * 10/06/98            ap
+ *     Changed to compile with C++.
+ * 18 Apr 98 at Apple
+ *     Mods for variable size giantDigit.
+ * 20 Jan 98 at Apple
+ *     Added curve param fields for CURVE_PARAM_VERSION 2.
+ * 17 Jul 97 at Apple
+ *     Added signature routines.
+ *  9 Jan 97 at NeXT
+ *     Split off from utilities.c
+ */
+
+#include "byteRep.h"
+#include "feeTypes.h"
+#include "curveParams.h"
+#include "giantIntegers.h"
+#include "elliptic.h"
+#include "falloc.h"
+#include "ckutilities.h"
+#include "feeDebug.h"
+#include <stdlib.h>
+
+#ifndef        NULL
+#define NULL   ((void *)0)
+#endif /* NULL */
+
+/*
+ * Support for portable bytestream representation of keys and signatures.
+ * Platform and endianness independent; format shared with JavaFEE
+ * implementation.
+ */
+
+/*
+ * Some handy macros.
+ */
+#define ENC_BYTE(n, b, bytes)                  \
+       *b++ = n;                               \
+       bytes++;
+
+#define ENC_INT(n, b, bytes, i)                        \
+       i = intToByteRep(n, b);                 \
+       bytes += i;                             \
+       b += i;
+
+#define ENC_GIANT(g, b, bytes, i)              \
+       i = giantToByteRep(g, b);               \
+       bytes += i;                             \
+       b += i;
+
+#define DEC_BYTE(n, b, blen, bytes)            \
+       n = *b++;                               \
+       bytes++;                                \
+       blen--;
+
+#define DEC_INT(n, b, blen, bytes)             \
+       n = byteRepToInt(b);                    \
+       b += sizeof(int);                       \
+       bytes += sizeof(int);                   \
+       blen -= gLen;
+
+#define DEC_GIANT(g, b, blen, glen, bytes, out)        \
+       g = byteRepToGiant(b, blen, &glen);     \
+       if(g == NULL) {                         \
+               goto out;                       \
+       }                                       \
+       b += glen;                              \
+       bytes += glen;                          \
+       blen -= gLen;
+
+
+
+
+/*
+ * The routines which convert various types to byte reps return the number
+ * of bytes written to the output stream.
+ */
+int intToByteRep(int i, unsigned char *buf)
+{
+       *buf++ = (unsigned char)((i >> 24) & 0xff);
+       *buf++ = (unsigned char)((i >> 16) & 0xff);
+       *buf++ = (unsigned char)((i >> 8)  & 0xff);
+       *buf   = (unsigned char)(i & 0xff);
+       return 4;
+}
+
+int shortToByteRep(short s, unsigned char *buf)
+{
+       *buf++ = (unsigned char)((s >> 8)  & 0xff);
+       *buf   = (unsigned char)(s & 0xff);
+       return 2;
+}
+
+/*
+ * 7 Apr 1998 : leading int is now the number of bytes in the giant's
+ * giantDigits array. This value is signed.
+ */
+int giantToByteRep(giant g, unsigned char *buf)
+{
+       int numBytes = g->sign * GIANT_BYTES_PER_DIGIT;
+       unsigned aNumBytes = abs(numBytes);
+
+       CKASSERT(g != NULL);
+       intToByteRep(numBytes, buf);
+       buf += sizeof(int);
+       serializeGiant(g, buf, aNumBytes);
+       return (sizeof(int) + aNumBytes);
+}
+
+int keyToByteRep(key k, unsigned char *buf)
+{
+       int numBytes = 0;
+       int i;
+
+       CKASSERT(k != NULL);
+       ENC_GIANT(k->x, buf, numBytes, i);
+
+       /* only write y for plus curve */
+       if(k->twist == CURVE_PLUS) {
+               CKASSERT(k->y != NULL);
+               ENC_GIANT(k->y, buf, numBytes, i);
+       }
+       return numBytes;
+}
+
+#define CURVE_PARAM_VERSION    3
+#define CURVE_PARAM_VERSION_MIN        3
+
+int curveParamsToByteRep(curveParams *cp, unsigned char *buf)
+{
+       int numBytes = 0;
+       int i;
+
+       CKASSERT(cp != NULL);
+       ENC_INT(CURVE_PARAM_VERSION, buf, numBytes, i);
+       ENC_INT(CURVE_PARAM_VERSION_MIN, buf, numBytes, i);
+       ENC_BYTE(cp->primeType, buf, numBytes);
+       ENC_BYTE(cp->curveType, buf, numBytes);
+       ENC_INT(cp->q, buf, numBytes, i);
+       ENC_INT(cp->k, buf, numBytes, i);
+       ENC_INT(cp->m, buf, numBytes, i);
+       ENC_INT(0, buf, numBytes, i);           // spare
+
+       ENC_GIANT(cp->a, buf, numBytes, i);
+       ENC_GIANT(cp->b, buf, numBytes, i);
+       ENC_GIANT(cp->c, buf, numBytes, i);
+       ENC_GIANT(cp->x1Plus, buf, numBytes, i);
+       ENC_GIANT(cp->x1Minus, buf, numBytes, i);
+       ENC_GIANT(cp->cOrderPlus, buf, numBytes, i);
+       ENC_GIANT(cp->cOrderMinus, buf, numBytes, i);
+       ENC_GIANT(cp->x1OrderPlus, buf, numBytes, i);
+       ENC_GIANT(cp->x1OrderMinus, buf, numBytes, i);
+       if(cp->primeType == FPT_General) {
+               ENC_GIANT(cp->basePrime, buf, numBytes, i);
+       }
+       return numBytes;
+}
+
+int sigToByteRep(int magic,
+       int version,
+       int minVersion,
+       giant g0,
+       giant g1,
+       unsigned char *buf)
+{
+       int numBytes = 0;
+       int i;
+
+       ENC_INT(magic, buf, numBytes, i);
+       ENC_INT(version, buf, numBytes, i);
+       ENC_INT(minVersion, buf, numBytes, i);
+       ENC_INT(0, buf, numBytes, i);           // spare
+       ENC_GIANT(g0, buf, numBytes, i);
+       ENC_GIANT(g1, buf, numBytes, i);
+
+       return numBytes;
+}
+
+
+/*
+ * return the size of various data types' byte representations.
+ */
+int lengthOfByteRepGiant(giant g)
+{
+       CKASSERT(g != NULL);
+       return sizeof(int) + (GIANT_BYTES_PER_DIGIT * abs(g->sign));
+}
+
+int lengthOfByteRepKey(key k)
+{
+       int len = lengthOfByteRepGiant(k->x);
+
+       CKASSERT(k != NULL);
+       if(k->twist == CURVE_PLUS) {
+               CKASSERT(k->y != NULL);
+               len += lengthOfByteRepGiant(k->y);
+       }
+       return len;
+}
+
+int lengthOfByteRepCurveParams(curveParams *cp)
+{
+       int length;
+
+       CKASSERT(cp != NULL);
+       length = (6 * sizeof(int)) +            // ver, minVers, q, k, m, spare
+               2 +                             // primeType + curveType
+               lengthOfByteRepGiant(cp->a) +
+               lengthOfByteRepGiant(cp->b) +
+               lengthOfByteRepGiant(cp->c) +
+               lengthOfByteRepGiant(cp->x1Plus) +
+               lengthOfByteRepGiant(cp->x1Minus) +
+               lengthOfByteRepGiant(cp->cOrderPlus) +
+               lengthOfByteRepGiant(cp->cOrderMinus) +
+               lengthOfByteRepGiant(cp->x1OrderPlus) +
+               lengthOfByteRepGiant(cp->x1OrderMinus);
+       if(cp->primeType == FPT_General) {
+               length += lengthOfByteRepGiant(cp->basePrime);
+       }
+       return length;
+}
+
+int lengthOfByteRepSig(giant g0,
+       giant g1)
+{
+       int length = (4 * sizeof(int)) +        // magic, version, minVersion,
+                                               // spare
+           lengthOfByteRepGiant(g0) +
+           lengthOfByteRepGiant(g1);
+       return length;
+}
+
+/*
+ * Routine to cons up various types from a byte rep stream.
+ */
+int byteRepToInt(const unsigned char *buf) {
+       int result;
+
+       result = (((int)buf[0] << 24) & 0xff000000) |
+                (((int)buf[1] << 16) & 0x00ff0000) |
+                (((int)buf[2] << 8) & 0xff00) |
+                (((int)buf[3]) & 0xff);
+       return result;
+}
+
+unsigned short byteRepToShort(const unsigned char *buf) {
+       unsigned short result;
+
+       result = (((unsigned short)buf[0] << 8) & 0xff00) |
+                (((unsigned short)buf[1]) & 0xff);
+       return result;
+}
+
+/*
+ * Probably need byteRepToShortArray...
+ */
+
+/*
+ * byte rep stream to giant. Returns NULL on error; returns number of bytes
+ * of *buf snarfed in *giantLen if successful.
+ *
+ * 7 Apr 1998 : leading int is now the number of bytes in the giant's
+ * giantDigits array. This value is signed.
+ */
+giant byteRepToGiant(const unsigned char *buf,
+       unsigned bufLen,
+       unsigned *giantLen)
+{
+       giant g;
+       int numDigits;
+       int numBytes;                   // signed!
+       unsigned aNumBytes;
+
+       if(bufLen < sizeof(int)) {
+               return (giant)NULL;
+       }
+       numBytes = byteRepToInt(buf);
+       aNumBytes = abs(numBytes);
+       numDigits = BYTES_TO_GIANT_DIGITS(aNumBytes);
+       buf += sizeof(int);
+       bufLen -= sizeof(int);
+       if(numDigits > MAX_DIGITS) {
+               return (giant)NULL;
+       }
+
+       if(bufLen < aNumBytes) {
+               return (giant)NULL;
+       }
+
+       /* 9 Apr 1998 - sign = 0 means no following n[] bytes in the
+        * byteRep. We do need to alloc one digit, in this case, though...
+        * Note that the giantstruct has one implicit digit in n[].
+        */
+       if(aNumBytes == 0) {
+           g = (giant)fmalloc(sizeof(giantstruct));
+           g->capacity = 1;
+       }
+       else {
+           g = (giant)fmalloc(sizeof(giantstruct) +
+               aNumBytes - GIANT_BYTES_PER_DIGIT);
+           g->capacity = numDigits;
+       }
+       deserializeGiant(buf, g, aNumBytes);
+
+       /* deserializeGiant always cooks up positive giant; sign is
+        * properly trimmed to handle trailing (M.S.) zeroes. */
+       if(numBytes < 0) {
+               g->sign = -g->sign;
+       }
+       *giantLen = sizeof(int) + aNumBytes;
+       return g;
+
+}
+
+/*
+ * Convert a byte stream (and some other parameters) into a
+ * keystruct.
+ * Returns NULL on error; returns number of bytes of *buf snarfed in
+ * *keyLen if successful.
+ */
+key byteRepToKey(const unsigned char *buf,
+       unsigned bufLen,
+       int twist,
+       curveParams *cp,
+       unsigned *keyLen)       // returned
+{
+       key k;
+       giant x;
+       giant y;
+       unsigned gLen;
+       unsigned totalLen;
+
+       x = byteRepToGiant(buf, bufLen, &gLen);
+       if(x == NULL) {
+               return NULL;
+       }
+       bufLen  -= gLen;
+       buf     += gLen;
+       totalLen = gLen;
+       if(twist == CURVE_PLUS) {
+               /* this also contains y */
+               y = byteRepToGiant(buf, bufLen, &gLen);
+               if(y == NULL) {
+                       freeGiant(x);
+                       return NULL;
+               }
+               totalLen += gLen;
+       }
+       else {
+               /* minus curve, y is not used */
+               y = newGiant(1);
+               int_to_giant(0, y);
+       }
+       k = (key)fmalloc(sizeof(keystruct));
+       k->twist = twist;
+       k->cp = cp;
+       k->x = x;
+       k->y = y;
+       *keyLen = totalLen;
+       return k;
+}
+
+curveParams *byteRepToCurveParams(const unsigned char *buf,
+       unsigned bufLen,
+       unsigned *cpLen)
+{
+       curveParams *cp;
+       unsigned gLen = 0;
+       int version;
+       int minVersion;
+       int spare;
+       int bytes = 0;
+
+       if(bufLen < (5 * sizeof(int))) {        // ver, minVers, q, k, spare
+               return NULL;
+       }
+       cp = newCurveParams();
+
+       DEC_INT(version, buf, bufLen, bytes);
+       DEC_INT(minVersion, buf, bufLen, bytes);
+       if(minVersion > CURVE_PARAM_VERSION) {
+               /*
+                * Can't parse this; things have changed too much between
+                * this version of the code and the time this curveParams
+                * was written.
+                */
+               goto abort;
+       }
+
+       DEC_BYTE(cp->primeType, buf, bufLen, bytes);
+       DEC_BYTE(cp->curveType, buf, bufLen, bytes);
+       DEC_INT(cp->q, buf, bufLen, bytes);
+       DEC_INT(cp->k, buf, bufLen, bytes);
+       DEC_INT(cp->m, buf, bufLen, bytes);
+       DEC_INT(spare, buf, bufLen, bytes);
+
+       DEC_GIANT(cp->a,                buf, bufLen, gLen, bytes, abort);
+       DEC_GIANT(cp->b,                buf, bufLen, gLen, bytes, abort);
+       DEC_GIANT(cp->c,                buf, bufLen, gLen, bytes, abort);
+       DEC_GIANT(cp->x1Plus,           buf, bufLen, gLen, bytes, abort);
+       DEC_GIANT(cp->x1Minus,          buf, bufLen, gLen, bytes, abort);
+       DEC_GIANT(cp->cOrderPlus,       buf, bufLen, gLen, bytes, abort);
+       DEC_GIANT(cp->cOrderMinus,      buf, bufLen, gLen, bytes, abort);
+       DEC_GIANT(cp->x1OrderPlus,      buf, bufLen, gLen, bytes, abort);
+       DEC_GIANT(cp->x1OrderMinus,     buf, bufLen, gLen, bytes, abort);
+
+       /*
+        * basePrime only present in byte rep for PT_GENERAL
+        */
+       if(cp->primeType == FPT_General) {
+           DEC_GIANT(cp->basePrime, buf, bufLen, gLen, bytes, abort);
+       }
+
+       /* remaining fields inferred */
+       curveParamsInferFields(cp);
+       allocRecipGiants(cp);
+
+       *cpLen = bytes;
+       return cp;
+
+abort:
+       freeCurveParams(cp);
+       return NULL;
+}
+
+/*
+ * Returns 0 if bad format, e.g., if minVersion of sig is > than codeVersion.
+ */
+int byteRepToSig(const unsigned char *buf,
+       unsigned bufLen,
+       int codeVersion,
+       int *sigMagic,                          // RETURNED
+       int *sigVersion,                        // RETURNED
+       int *sigMinVersion,                     // RETURNED
+       giant *g0,                                      // alloc'd  & RETURNED
+       giant *g1)                                      // alloc'd  & RETURNED
+{
+       unsigned gLen = 0;
+       int spare;
+       int bytes = 0;
+
+       if(bufLen < (4 * sizeof(int))) {        // magic, version, minVersion,
+                                               // spare
+               return 0;
+       }
+       DEC_INT(*sigMagic, buf, bufLen, bytes);
+       DEC_INT(*sigVersion, buf, bufLen, bytes);
+       DEC_INT(*sigMinVersion, buf, bufLen, bytes);
+       if(*sigMinVersion > codeVersion) {
+               return 0;
+       }
+       DEC_INT(spare, buf, bufLen, bytes);
+       // deleted 2/20/01 DEC_INT(*signerLen, buf, bufLen, bytes);
+       // deleted 2/20/01 *signer = byteRepToUnichars(buf, *signerLen);
+       // deleted 2/20/01 buf += (2 * *signerLen);
+       // deleted 2/20/01 bufLen -= (2 * *signerLen);
+       DEC_GIANT(*g0, buf, bufLen, gLen, bytes, abort);
+       DEC_GIANT(*g1, buf, bufLen, gLen, bytes, abort);
+
+       return 1;
+abort:
+       return 0;
+}