diff options
Diffstat (limited to 'security/nss/cmd/lib/berparse.c')
| -rw-r--r-- | security/nss/cmd/lib/berparse.c | 388 |
1 files changed, 388 insertions, 0 deletions
diff --git a/security/nss/cmd/lib/berparse.c b/security/nss/cmd/lib/berparse.c new file mode 100644 index 000000000..8cd1ebae0 --- /dev/null +++ b/security/nss/cmd/lib/berparse.c @@ -0,0 +1,388 @@ +/* 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; + } +} |