/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "secutil.h"
typedef enum {
tagDone,
lengthDone,
leafDone,
compositeDone,
notDone,
parseError,
parseComplete
} ParseState;
typedef unsigned char Byte;
typedef void (*ParseProc)(BERParse *h,
unsigned char **buf,
int *len);
typedef struct {
SECArb arb;
int pos;
/* length from global start to item start */
SECArb *parent;
} ParseStackElem;
struct BERParseStr {
PLArenaPool *his;
PLArenaPool *mine;
ParseProc proc;
int stackDepth;
ParseStackElem *stackPtr;
ParseStackElem *stack;
int pending;
/* bytes remaining to complete this part */
int pos;
/* running length of consumed characters */
ParseState state;
PRBool keepLeaves;
PRBool derOnly;
BERFilterProc filter;
void *filterArg;
BERNotifyProc before;
void *beforeArg;
BERNotifyProc after;
void *afterArg;
};
#define UNKNOWN -1
static unsigned char
NextChar(BERParse *h,
unsigned char **buf,
int *len)
{
unsigned char c = *(*buf)++;
(*len)--;
h->pos++;
if (h->filter)
(*h->filter)(h->filterArg, &c, 1);
return c;
}
static void
ParseTag(BERParse *h,
unsigned char **buf,
int *len)
{
SECArb *arb = &(h->stackPtr->arb);
arb->tag = NextChar(h, buf, len);
PORT_Assert(h->state == notDone);
/*
* NOTE: This does not handle the high-tag-number form
*/
if ((arb->tag & DER_HIGH_TAG_NUMBER) == DER_HIGH_TAG_NUMBER) {
PORT_SetError(SEC_ERROR_BAD_DER);
h->state = parseError;
return;
}
h->pending = UNKNOWN;
arb->length = UNKNOWN;
if (arb->tag & DER_CONSTRUCTED) {
arb->body.cons.numSubs = 0;
arb->body.cons.subs = NULL;
}
else {
arb->body.item.len = UNKNOWN;
arb->body.item.data = NULL;
}
h->state = tagDone;
}
static void
ParseLength(BERParse *h,
unsigned char **buf,
int *len)
{
Byte b;
SECArb *arb = &(h->stackPtr->arb);
PORT_Assert(h->state == notDone);
if (h->pending == UNKNOWN) {
b = NextChar(h, buf, len);
if ((b & 0x80) == 0) {
/* short form */
arb->length = b;
/*
* if the tag and the length are both zero bytes, then this
* should be the marker showing end of list for the
* indefinite length composite
*/
if (arb->length == 0 && arb->tag == 0)
h->state = compositeDone;
else
h->state = lengthDone;
return;
}
h->pending = b & 0x7f;
/* 0 implies this is an indefinite length */
if (h->pending > 4) {
PORT_SetError(SEC_ERROR_BAD_DER);
h->state = parseError;
return;
}
arb->length = 0;
}
while ((*len > 0) && (h->pending > 0)) {
b = NextChar(h, buf, len);
arb->length = (arb->length << 8) + b;
h->pending--;
}
if (h->pending == 0) {
if (h->derOnly && (arb->length == 0))
h->state = parseError;
else
h->state = lengthDone;
}
return;
}
static void
ParseLeaf(BERParse *h,
unsigned char **buf,
int *len)
{
int count;
SECArb *arb = &(h->stackPtr->arb);
PORT_Assert(h->state == notDone);
PORT_Assert(h->pending >= 0);
if (*len < h->pending)
count = *len;
else
count = h->pending;
if (h->keepLeaves)
memcpy(arb->body.item.data + arb->body.item.len, *buf, count);
if (h->filter)
(*h->filter)(h->filterArg, *buf, count);
*buf += count;
*len -= count;
arb->body.item.len += count;
h->pending -= count;
h->pos += count;
if (h->pending == 0) {
h->state = leafDone;
}
return;
}
static void
CreateArbNode(BERParse *h)
{
SECArb *arb = PORT_ArenaAlloc(h->his,
sizeof(SECArb));
*arb = h->stackPtr->arb;
/*
* Special case closing the root
*/
if (h->stackPtr == h->stack) {
PORT_Assert(arb->tag & DER_CONSTRUCTED);
h->state = parseComplete;
}
else {
SECArb *parent = h->stackPtr->parent;
parent->body.cons.subs = DS_ArenaGrow(
h->his, parent->body.cons.subs,
(parent->body.cons.numSubs) *
sizeof(SECArb *),
(parent->body.cons.numSubs + 1) *
sizeof(SECArb *));
parent->body.cons.subs[parent->body.cons.numSubs] = arb;
parent->body.cons.numSubs++;
h->proc = ParseTag;
h->state = notDone;
h->pending = UNKNOWN;
}
if (h->after)
(*h->after)(h->afterArg, arb, h->stackPtr - h->stack, PR_FALSE);
}
SECStatus
BER_ParseSome(BERParse *h,
unsigned char *buf,
int len)
{
if (h->state == parseError)
return PR_TRUE;
while (len) {
(*h->proc)(h, &buf, &len);
if (h->state == parseComplete) {
PORT_SetError(SEC_ERROR_BAD_DER);
h->state = parseError;
return PR_TRUE;
}
if (h->state == parseError)
return PR_TRUE;
PORT_Assert(h->state != parseComplete);
if (h->state <= compositeDone) {
if (h->proc == ParseTag) {
PORT_Assert(h->state == tagDone);
h->proc = ParseLength;
h->state = notDone;
}
else if (h->proc == ParseLength) {
SECArb *arb = &(h->stackPtr->arb);
PORT_Assert(h->state == lengthDone || h->state == compositeDone);
if (h->before)
(*h->before)(h->beforeArg, arb,
h->stackPtr - h->stack, PR_TRUE);
/*
* Check to see if this is the end of an indefinite
* length composite
*/
if (h->state == compositeDone) {
SECArb *parent = h->stackPtr->parent;
PORT_Assert(parent);
PORT_Assert(parent->tag & DER_CONSTRUCTED);
if (parent->length != 0) {
PORT_SetError(SEC_ERROR_BAD_DER);
h->state = parseError;
return PR_TRUE;
}
/*
* NOTE: This does not check for an indefinite length
* composite being contained inside a definite length
* composite. It is not clear that is legal.
*/
h->stackPtr--;
CreateArbNode(h);
}
else {
h->stackPtr->pos = h->pos;
if (arb->tag & DER_CONSTRUCTED) {
SECArb *parent;
/*
* Make sure there is room on the stack before we
* stick anything else there.
*/
PORT_Assert(h->stackPtr - h->stack < h->stackDepth);
if (h->stackPtr - h->stack == h->stackDepth - 1) {
int newDepth = h->stackDepth * 2;
h->stack = DS_ArenaGrow(h->mine, h->stack,
sizeof(ParseStackElem) *
h->stackDepth,
sizeof(ParseStackElem) *
newDepth);
h->stackPtr = h->stack + h->stackDepth + 1;
h->stackDepth = newDepth;
}
parent = &(h->stackPtr->arb);
h->stackPtr++;
h->stackPtr->parent = parent;
h->proc = ParseTag;
h->state = notDone;
h->pending = UNKNOWN;
}
else {
if (arb->length < 0) {
PORT_SetError(SEC_ERROR_BAD_DER);
h->state = parseError;
return PR_TRUE;
}
arb->body.item.len = 0;
if (arb->length > 0 && h->keepLeaves) {
arb->body.item.data =
PORT_ArenaAlloc(h->his, arb->length);
}
else {
arb->body.item.data = NULL;
}
h->proc = ParseLeaf;
h->state = notDone;
h->pending = arb->length;
}
}
}
else {
ParseStackElem *parent;
PORT_Assert(h->state = leafDone);
PORT_Assert(h->proc == ParseLeaf);
for (;;) {
CreateArbNode(h);
if (h->stackPtr == h->stack)
break;
parent = (h->stackPtr - 1);
PORT_Assert(parent->arb.tag & DER_CONSTRUCTED);
if (parent->arb.length == 0)
/* need explicit end */
break;
if (parent->pos + parent->arb.length > h->pos)
break;
if (parent->pos + parent->arb.length < h->pos) {
PORT_SetError(SEC_ERROR_BAD_DER);
h->state = parseError;
return PR_TRUE;
}
h->stackPtr = parent;
}
}
}
}
return PR_FALSE;
}
BERParse *
BER_ParseInit(PLArenaPool *arena, PRBool derOnly)
{
BERParse *h;
PLArenaPool *temp = PORT_NewArena(DER_DEFAULT_CHUNKSIZE);
if (temp == NULL) {
PORT_SetError(SEC_ERROR_NO_MEMORY);
return NULL;
}
h = PORT_ArenaAlloc(temp,
sizeof(BERParse));
if (h == NULL) {
PORT_FreeArena(temp, PR_FALSE);
PORT_SetError(SEC_ERROR_NO_MEMORY);
return NULL;
}
h->his = arena;
h->mine = temp;
h->proc = ParseTag;
h->stackDepth = 20;
h->stack = PORT_ArenaZAlloc(h->mine,
sizeof(ParseStackElem) * h->stackDepth);
h->stackPtr = h->stack;
h->state = notDone;
h->pos = 0;
h->keepLeaves = PR_TRUE;
h->before = NULL;
h->after = NULL;
h->filter = NULL;
h->derOnly = derOnly;
return h;
}
SECArb *
BER_ParseFini(BERParse *h)
{
PLArenaPool *myArena = h->mine;
SECArb *arb;
if (h->state != parseComplete) {
arb = NULL;
}
else {
arb = PORT_ArenaAlloc(h->his,
sizeof(SECArb));
*arb = h->stackPtr->arb;
}
PORT_FreeArena(myArena, PR_FALSE);
return arb;
}
void
BER_SetFilter(BERParse *h, BERFilterProc proc,
void *instance)
{
h->filter = proc;
h->filterArg = instance;
}
void
BER_SetLeafStorage(BERParse *h, PRBool keep)
{
h->keepLeaves = keep;
}
void
BER_SetNotifyProc(BERParse *h, BERNotifyProc proc,
void *instance,
PRBool beforeData)
{
if (beforeData) {
h->before = proc;
h->beforeArg = instance;
}
else {
h->after = proc;
h->afterArg = instance;
}
}
