+ASN1_INTEGER *ASN1_INTEGER_dup(const ASN1_INTEGER *x)
+{
+ return ASN1_STRING_dup(x);
+}
+
+int ASN1_INTEGER_cmp(const ASN1_INTEGER *x, const ASN1_INTEGER *y)
+{
+ int neg, ret;
+ /* Compare signs */
+ neg = x->type & V_ASN1_NEG;
+ if (neg != (y->type & V_ASN1_NEG)) {
+ if (neg)
+ return -1;
+ else
+ return 1;
+ }
+
+ ret = ASN1_STRING_cmp(x, y);
+
+ if (neg)
+ return -ret;
+ else
+ return ret;
+}
+
+/*-
+ * This converts a big endian buffer and sign into its content encoding.
+ * This is used for INTEGER and ENUMERATED types.
+ * The internal representation is an ASN1_STRING whose data is a big endian
+ * representation of the value, ignoring the sign. The sign is determined by
+ * the type: if type & V_ASN1_NEG is true it is negative, otherwise positive.
+ *
+ * Positive integers are no problem: they are almost the same as the DER
+ * encoding, except if the first byte is >= 0x80 we need to add a zero pad.
+ *
+ * Negative integers are a bit trickier...
+ * The DER representation of negative integers is in 2s complement form.
+ * The internal form is converted by complementing each octet and finally
+ * adding one to the result. This can be done less messily with a little trick.
+ * If the internal form has trailing zeroes then they will become FF by the
+ * complement and 0 by the add one (due to carry) so just copy as many trailing
+ * zeros to the destination as there are in the source. The carry will add one
+ * to the last none zero octet: so complement this octet and add one and finally
+ * complement any left over until you get to the start of the string.
+ *
+ * Padding is a little trickier too. If the first bytes is > 0x80 then we pad
+ * with 0xff. However if the first byte is 0x80 and one of the following bytes
+ * is non-zero we pad with 0xff. The reason for this distinction is that 0x80
+ * followed by optional zeros isn't padded.
+ */
+
+/*
+ * If |pad| is zero, the operation is effectively reduced to memcpy,
+ * and if |pad| is 0xff, then it performs two's complement, ~dst + 1.
+ * Note that in latter case sequence of zeros yields itself, and so
+ * does 0x80 followed by any number of zeros. These properties are
+ * used elsewhere below...
+ */
+static void twos_complement(unsigned char *dst, const unsigned char *src,
+ size_t len, unsigned char pad)
+{
+ unsigned int carry = pad & 1;
+
+ /* Begin at the end of the encoding */
+ dst += len;
+ src += len;
+ /* two's complement value: ~value + 1 */
+ while (len-- != 0) {
+ *(--dst) = (unsigned char)(carry += *(--src) ^ pad);
+ carry >>= 8;
+ }
+}
+
+static size_t i2c_ibuf(const unsigned char *b, size_t blen, int neg,
+ unsigned char **pp)
+{
+ unsigned int pad = 0;
+ size_t ret, i;
+ unsigned char *p, pb = 0;
+
+ if (b != NULL && blen) {
+ ret = blen;
+ i = b[0];
+ if (!neg && (i > 127)) {
+ pad = 1;
+ pb = 0;
+ } else if (neg) {
+ pb = 0xFF;
+ if (i > 128) {
+ pad = 1;
+ } else if (i == 128) {
+ /*
+ * Special case [of minimal negative for given length]:
+ * if any other bytes non zero we pad, otherwise we don't.
+ */
+ for (pad = 0, i = 1; i < blen; i++)
+ pad |= b[i];
+ pb = pad != 0 ? 0xffU : 0;
+ pad = pb & 1;
+ }
+ }
+ ret += pad;
+ } else {
+ ret = 1;
+ blen = 0; /* reduce '(b == NULL || blen == 0)' to '(blen == 0)' */
+ }
+
+ if (pp == NULL || (p = *pp) == NULL)
+ return ret;
+
+ /*
+ * This magically handles all corner cases, such as '(b == NULL ||
+ * blen == 0)', non-negative value, "negative" zero, 0x80 followed
+ * by any number of zeros...
+ */
+ *p = pb;
+ p += pad; /* yes, p[0] can be written twice, but it's little
+ * price to pay for eliminated branches */
+ twos_complement(p, b, blen, pb);
+
+ *pp += ret;
+ return ret;
+}
+
+/*
+ * convert content octets into a big endian buffer. Returns the length
+ * of buffer or 0 on error: for malformed INTEGER. If output buffer is
+ * NULL just return length.
+ */
+
+static size_t c2i_ibuf(unsigned char *b, int *pneg,
+ const unsigned char *p, size_t plen)
+{
+ int neg, pad;
+ /* Zero content length is illegal */
+ if (plen == 0) {
+ ASN1err(ASN1_F_C2I_IBUF, ASN1_R_ILLEGAL_ZERO_CONTENT);
+ return 0;
+ }
+ neg = p[0] & 0x80;
+ if (pneg)
+ *pneg = neg;
+ /* Handle common case where length is 1 octet separately */
+ if (plen == 1) {
+ if (b != NULL) {
+ if (neg)
+ b[0] = (p[0] ^ 0xFF) + 1;
+ else
+ b[0] = p[0];
+ }
+ return 1;
+ }
+
+ pad = 0;
+ if (p[0] == 0) {
+ pad = 1;
+ } else if (p[0] == 0xFF) {
+ size_t i;
+
+ /*
+ * Special case [of "one less minimal negative" for given length]:
+ * if any other bytes non zero it was padded, otherwise not.
+ */
+ for (pad = 0, i = 1; i < plen; i++)
+ pad |= p[i];
+ pad = pad != 0 ? 1 : 0;
+ }
+ /* reject illegal padding: first two octets MSB can't match */
+ if (pad && (neg == (p[1] & 0x80))) {
+ ASN1err(ASN1_F_C2I_IBUF, ASN1_R_ILLEGAL_PADDING);
+ return 0;
+ }
+
+ /* skip over pad */
+ p += pad;
+ plen -= pad;
+
+ if (b != NULL)
+ twos_complement(b, p, plen, neg ? 0xffU : 0);
+
+ return plen;
+}
+
+int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)
+{
+ return i2c_ibuf(a->data, a->length, a->type & V_ASN1_NEG, pp);
+}
+
+/* Convert big endian buffer into uint64_t, return 0 on error */
+static int asn1_get_uint64(uint64_t *pr, const unsigned char *b, size_t blen)
+{
+ size_t i;
+ uint64_t r;
+
+ if (blen > sizeof(*pr)) {
+ ASN1err(ASN1_F_ASN1_GET_UINT64, ASN1_R_TOO_LARGE);
+ return 0;
+ }
+ if (b == NULL)
+ return 0;
+ for (r = 0, i = 0; i < blen; i++) {
+ r <<= 8;
+ r |= b[i];
+ }
+ *pr = r;
+ return 1;
+}
+
+/*
+ * Write uint64_t to big endian buffer and return offset to first
+ * written octet. In other words it returns offset in range from 0
+ * to 7, with 0 denoting 8 written octets and 7 - one.
+ */
+static size_t asn1_put_uint64(unsigned char b[sizeof(uint64_t)], uint64_t r)
+{
+ size_t off = sizeof(uint64_t);
+
+ do {
+ b[--off] = (unsigned char)r;
+ } while (r >>= 8);
+
+ return off;
+}
+
+/*
+ * Absolute value of INT64_MIN: we can't just use -INT64_MIN as gcc produces
+ * overflow warnings.