// This function is used to retrieve the lenght of a DER encoded
// item. It looks to see if this a multibyte length and then
// interprets the buffer accordingly to get the actual length value.
// This funciton is used mostly while parsing the DER headers.
//
// A DER encoded item has the following structure:
//
// <tag><length<data consisting of lenght bytes>
static int32_t
getDERItemLength(unsigned char *data, unsigned char *end,
unsigned long *bytesUsed, bool *indefinite)
{
unsigned char lbyte = *data++;
int32_t length = -1;
*indefinite = false;
if (lbyte >= 0x80) {
// Multibyte length
unsigned nb = (unsigned) (lbyte & 0x7f);
if (nb > 4) {
return -1;
}
if (nb > 0) {
if ((data+nb) > end) {
return -1;
}
length = getInteger256(data, nb);
if (length < 0)
return -1;
} else {
*indefinite = true;
length = 0;
}
*bytesUsed = nb+1;
} else {
length = lbyte;
*bytesUsed = 1;
}
return length;
}
static int
prettyPrintLength(FILE *out, const unsigned char *data, const unsigned char *end,
int *lenp, PRBool *indefinitep, unsigned int lv, PRBool raw)
{
unsigned char lbyte;
int lenLen;
int rv;
if (data >= end) {
PORT_SetError(SEC_ERROR_BAD_DER);
return -1;
}
rv = fprintf(out, " ");
if (rv < 0) {
PORT_SetError(SEC_ERROR_IO);
return rv;
}
*indefinitep = PR_FALSE;
lbyte = *data++;
if (lbyte >= 0x80) {
/* Multibyte length */
unsigned nb = (unsigned) (lbyte & 0x7f);
if (nb > 4) {
PORT_SetError(SEC_ERROR_BAD_DER);
return -1;
}
if (nb > 0) {
int il;
if ((data + nb) > end) {
PORT_SetError(SEC_ERROR_BAD_DER);
return -1;
}
il = getInteger256(data, nb);
if (il < 0) return -1;
*lenp = (unsigned) il;
} else {
*lenp = 0;
*indefinitep = PR_TRUE;
}
lenLen = nb + 1;
if (raw) {
unsigned int i;
rv = prettyPrintByte(out, lbyte, lv);
if (rv < 0)
return rv;
for (i = 0; i < nb; i++) {
rv = prettyPrintByte(out, data[i], lv);
if (rv < 0)
return rv;
}
}
} else {
*lenp = lbyte;
lenLen = 1;
if (raw) {
rv = prettyPrintByte(out, lbyte, lv);
if (rv < 0)
return rv;
}
}
if (*indefinitep)
rv = fprintf(out, "(indefinite)\n");
else
rv = fprintf(out, "(%d)\n", *lenp);
if (rv < 0) {
PORT_SetError(SEC_ERROR_IO);
return rv;
}
prettyColumn = -1;
return lenLen;
}
