ECDSA signatures need a zero padding for the ASN.1 storage of the R and S values
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@ -4390,6 +4390,9 @@ int StoreECC_DSA_Sig(byte* out, word32* outLen, mp_int* r, mp_int* s)
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word32 sSz;
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word32 headerSz = 4; /* 2*ASN_TAG + 2*LEN(ENUM) */
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/* If the leading bit on the INTEGER is a 1, add a leading zero */
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int rLeadingZero = mp_leading_bit(r);
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int sLeadingZero = mp_leading_bit(s);
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int rLen = mp_unsigned_bin_size(r); /* big int size */
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int sLen = mp_unsigned_bin_size(s);
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int err;
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@ -4397,20 +4400,24 @@ int StoreECC_DSA_Sig(byte* out, word32* outLen, mp_int* r, mp_int* s)
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if (*outLen < (rLen + sLen + headerSz + 2)) /* SEQ_TAG + LEN(ENUM) */
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return BAD_FUNC_ARG;
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idx = SetSequence(rLen + sLen + headerSz, out);
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idx = SetSequence(rLen+rLeadingZero+sLen+sLeadingZero+headerSz, out);
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/* store r */
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out[idx++] = ASN_INTEGER;
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rSz = SetLength(rLen, &out[idx]);
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rSz = SetLength(rLen + rLeadingZero, &out[idx]);
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idx += rSz;
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if (rLeadingZero)
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out[idx++] = 0;
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err = mp_to_unsigned_bin(r, &out[idx]);
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if (err != MP_OKAY) return err;
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idx += rLen;
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/* store s */
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out[idx++] = ASN_INTEGER;
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sSz = SetLength(sLen, &out[idx]);
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sSz = SetLength(sLen + sLeadingZero, &out[idx]);
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idx += sSz;
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if (sLeadingZero)
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out[idx++] = 0;
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err = mp_to_unsigned_bin(s, &out[idx]);
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if (err != MP_OKAY) return err;
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idx += sLen;
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@ -179,6 +179,28 @@ mp_count_bits (mp_int * a)
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}
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int mp_leading_bit (mp_int * a)
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{
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int bit = 0;
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mp_int t;
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if (mp_init_copy(&t, a) != MP_OKAY)
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return 0;
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while (mp_iszero(&t) == 0) {
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#ifndef MP_8BIT
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bit = (t.dp[0] & 0x80) != 0;
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#else
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bit = (t.dp[0] | ((t.dp[1] & 0x01) << 7)) & 0x80 != 0;
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#endif
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if (mp_div_2d (&t, 8, &t, NULL) != MP_OKAY)
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break;
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}
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mp_clear(&t);
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return bit;
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}
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/* store in unsigned [big endian] format */
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int mp_to_unsigned_bin (mp_int * a, unsigned char *b)
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{
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@ -1706,6 +1706,25 @@ int fp_count_bits (fp_int * a)
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return r;
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}
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int fp_leading_bit(fp_int *a)
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{
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int bit = 0;
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if (a->used != 0) {
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fp_digit q = a->dp[a->used - 1];
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int qSz = sizeof(fp_digit);
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while (qSz > 0) {
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if ((unsigned char)q != 0)
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bit = (q & 0x80) != 0;
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q >>= 8;
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qSz--;
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}
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}
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return bit;
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}
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void fp_lshd(fp_int *a, int x)
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{
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int y;
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@ -1968,6 +1987,12 @@ int mp_count_bits (mp_int* a)
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}
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int mp_leading_bit (mp_int* a)
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{
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return fp_leading_bit(a);
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}
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/* fast math conversion */
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void mp_rshb (mp_int* a, int x)
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{
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@ -225,6 +225,7 @@ int mp_exptmod (mp_int * G, mp_int * X, mp_int * P, mp_int * Y);
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/* functions added to support above needed, removed TOOM and KARATSUBA */
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int mp_count_bits (mp_int * a);
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int mp_leading_bit (mp_int * a);
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int mp_init_copy (mp_int * a, mp_int * b);
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int mp_copy (mp_int * a, mp_int * b);
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int mp_grow (mp_int * a, int size);
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@ -490,6 +490,7 @@ int fp_exptmod(fp_int *a, fp_int *b, fp_int *c, fp_int *d);
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/* radix conersions */
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int fp_count_bits(fp_int *a);
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int fp_leading_bit(fp_int *a);
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int fp_unsigned_bin_size(fp_int *a);
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void fp_read_unsigned_bin(fp_int *a, unsigned char *b, int c);
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@ -655,6 +656,7 @@ int mp_copy(fp_int* a, fp_int* b);
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int mp_isodd(mp_int* a);
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int mp_iszero(mp_int* a);
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int mp_count_bits(mp_int *a);
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int mp_leading_bit(mp_int *a);
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int mp_set_int(fp_int *a, fp_digit b);
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void mp_rshb(mp_int *a, int x);
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@ -8433,7 +8433,7 @@ static void PickHashSigAlgo(CYASSL* ssl,
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ret = EccPrivateKeyDecode(ssl->buffers.key.buffer, &i,
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&dsaKey, ssl->buffers.key.length);
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if (ret != 0) return ret;
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sigSz = ecc_sig_size(&dsaKey) + 2; /* worst case estimate */
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sigSz = ecc_sig_size(&dsaKey) + 4; /* worst case estimate */
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}
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else {
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#ifndef NO_RSA
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