diff options
Diffstat (limited to 'security/nss/lib/util/quickder.c')
| -rw-r--r-- | security/nss/lib/util/quickder.c | 837 |
1 files changed, 837 insertions, 0 deletions
diff --git a/security/nss/lib/util/quickder.c b/security/nss/lib/util/quickder.c new file mode 100644 index 0000000000..86f0fae2dc --- /dev/null +++ b/security/nss/lib/util/quickder.c @@ -0,0 +1,837 @@ +/* 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/. */ + +/* + Optimized ASN.1 DER decoder +*/ + +#include "secerr.h" +#include "secasn1.h" /* for SEC_ASN1GetSubtemplate */ +#include "secitem.h" + +/* + * simple definite-length ASN.1 decoder + */ + +static unsigned char* +definite_length_decoder(const unsigned char* buf, + const unsigned int buf_length, + unsigned int* out_data_length, + PRBool includeTag) +{ + unsigned char tag; + unsigned int used_length = 0; + unsigned int data_length = 0; + unsigned char length_field_len = 0; + unsigned char byte; + unsigned int i; + + if (used_length >= buf_length) { + /* Tag field was not found! */ + return NULL; + } + tag = buf[used_length++]; + + if (tag == 0) { + /* End-of-contents octects should not be present in DER because + DER doesn't use the indefinite length form. */ + return NULL; + } + + if ((tag & 0x1F) == 0x1F) { + /* High tag number (a tag number > 30) is not supported */ + return NULL; + } + + if (used_length >= buf_length) { + /* Length field was not found! */ + return NULL; + } + byte = buf[used_length++]; + + if (!(byte & 0x80)) { + /* Short form: The high bit is not set. */ + data_length = byte; /* clarity; we're returning a 32-bit int. */ + } else { + /* Long form. Extract the field length */ + length_field_len = byte & 0x7F; + if (length_field_len == 0) { + /* DER doesn't use the indefinite length form. */ + return NULL; + } + + if (length_field_len > sizeof(data_length)) { + /* We don't support an extended length field longer than + 4 bytes (2^32) */ + return NULL; + } + + if (length_field_len > (buf_length - used_length)) { + /* Extended length field was not found */ + return NULL; + } + + /* Iterate across the extended length field */ + for (i = 0; i < length_field_len; i++) { + byte = buf[used_length++]; + data_length = (data_length << 8) | byte; + + if (i == 0) { + PRBool too_long = PR_FALSE; + if (length_field_len == 1) { + too_long = ((byte & 0x80) == 0); /* Short form suffices */ + } else { + too_long = (byte == 0); /* This zero byte can be omitted */ + } + if (too_long) { + /* The length is longer than needed. */ + return NULL; + } + } + } + } + + if ((tag & SEC_ASN1_TAGNUM_MASK) == SEC_ASN1_NULL && data_length != 0) { + /* The DER encoding of NULL has no contents octets */ + return NULL; + } + + if (data_length > (buf_length - used_length)) { + /* The decoded length exceeds the available buffer */ + return NULL; + } + + if (includeTag) { + data_length += used_length; + } + + *out_data_length = data_length; + return ((unsigned char*)buf + (includeTag ? 0 : used_length)); +} + +static SECStatus +GetItem(SECItem* src, SECItem* dest, PRBool includeTag) +{ + if ((!src) || (!dest) || (!src->data && src->len)) { + PORT_SetError(SEC_ERROR_INVALID_ARGS); + return SECFailure; + } + + if (!src->len) { + /* reaching the end of the buffer is not an error */ + dest->data = NULL; + dest->len = 0; + return SECSuccess; + } + + dest->data = definite_length_decoder(src->data, src->len, &dest->len, + includeTag); + if (dest->data == NULL) { + PORT_SetError(SEC_ERROR_BAD_DER); + return SECFailure; + } + src->len -= (int)(dest->data - src->data) + dest->len; + src->data = dest->data + dest->len; + return SECSuccess; +} + +/* check if the actual component's type matches the type in the template */ + +static SECStatus +MatchComponentType(const SEC_ASN1Template* templateEntry, + SECItem* item, PRBool* match, void* dest) +{ + unsigned long kind = 0; + unsigned char tag = 0; + + if ((!item) || (!item->data && item->len) || (!templateEntry) || (!match)) { + PORT_SetError(SEC_ERROR_INVALID_ARGS); + return SECFailure; + } + + if (!item->len) { + *match = PR_FALSE; + return SECSuccess; + } + + kind = templateEntry->kind; + tag = *(unsigned char*)item->data; + + if (((kind & SEC_ASN1_INLINE) || + (kind & SEC_ASN1_POINTER)) && + (0 == (kind & SEC_ASN1_TAG_MASK))) { + /* These cases are special because the template's "kind" does not + give us the information for the ASN.1 tag of the next item. It can + only be figured out from the subtemplate. */ + if (!(kind & SEC_ASN1_OPTIONAL)) { + /* This is a required component. If there is a type mismatch, + the decoding of the subtemplate will fail, so assume this + is a match at the parent level and let it fail later. This + avoids a redundant check in matching cases */ + *match = PR_TRUE; + return SECSuccess; + } else { + /* optional component. This is the hard case. Now we need to + look at the subtemplate to get the expected kind */ + const SEC_ASN1Template* subTemplate = + SEC_ASN1GetSubtemplate(templateEntry, dest, PR_FALSE); + if (!subTemplate) { + PORT_SetError(SEC_ERROR_BAD_TEMPLATE); + return SECFailure; + } + if ((subTemplate->kind & SEC_ASN1_INLINE) || + (subTemplate->kind & SEC_ASN1_POINTER)) { + /* disallow nesting SEC_ASN1_POINTER and SEC_ASN1_INLINE, + otherwise you may get a false positive due to the recursion + optimization above that always matches the type if the + component is required . Nesting these should never be + required, so that no one should miss this ability */ + PORT_SetError(SEC_ERROR_BAD_TEMPLATE); + return SECFailure; + } + return MatchComponentType(subTemplate, item, match, + (void*)((char*)dest + templateEntry->offset)); + } + } + + if (kind & SEC_ASN1_CHOICE) { + /* we need to check the component's tag against each choice's tag */ + /* XXX it would be nice to save the index of the choice here so that + DecodeChoice wouldn't have to do this again. However, due to the + recursivity of MatchComponentType, we don't know if we are in a + required or optional component, so we can't write anywhere in + the destination within this function */ + unsigned choiceIndex = 1; + const SEC_ASN1Template* choiceEntry; + while ((choiceEntry = &templateEntry[choiceIndex++]) && (choiceEntry->kind)) { + if ((SECSuccess == MatchComponentType(choiceEntry, item, match, + (void*)((char*)dest + choiceEntry->offset))) && + (PR_TRUE == *match)) { + return SECSuccess; + } + } + /* no match, caller must decide if this is BAD DER, or not. */ + *match = PR_FALSE; + return SECSuccess; + } + + if (kind & SEC_ASN1_ANY) { + /* SEC_ASN1_ANY always matches */ + *match = PR_TRUE; + return SECSuccess; + } + + if ((0 == ((unsigned char)kind & SEC_ASN1_TAGNUM_MASK)) && + (!(kind & SEC_ASN1_EXPLICIT)) && + (((kind & SEC_ASN1_SAVE) || + (kind & SEC_ASN1_SKIP)) && + (!(kind & SEC_ASN1_OPTIONAL)))) { + /* when saving or skipping a required component, a type is not + required in the template. This is for legacy support of + SEC_ASN1_SAVE and SEC_ASN1_SKIP only. XXX I would like to + deprecate these usages and always require a type, as this + disables type checking, and effectively forbids us from + transparently ignoring optional components we aren't aware of */ + *match = PR_TRUE; + return SECSuccess; + } + + /* first, do a class check */ + if ((tag & SEC_ASN1_CLASS_MASK) != + (((unsigned char)kind) & SEC_ASN1_CLASS_MASK)) { + /* this is only to help debugging of the decoder in case of problems */ + /* unsigned char tagclass = tag & SEC_ASN1_CLASS_MASK; */ + /* unsigned char expectedclass = (unsigned char)kind & SEC_ASN1_CLASS_MASK; */ + *match = PR_FALSE; + return SECSuccess; + } + + /* now do a tag check */ + if (((unsigned char)kind & SEC_ASN1_TAGNUM_MASK) != + (tag & SEC_ASN1_TAGNUM_MASK)) { + *match = PR_FALSE; + return SECSuccess; + } + + /* now, do a method check. This depends on the class */ + switch (tag & SEC_ASN1_CLASS_MASK) { + case SEC_ASN1_UNIVERSAL: + /* For types of the SEC_ASN1_UNIVERSAL class, we know which must be + primitive or constructed based on the tag */ + switch (tag & SEC_ASN1_TAGNUM_MASK) { + case SEC_ASN1_SEQUENCE: + case SEC_ASN1_SET: + case SEC_ASN1_EMBEDDED_PDV: + /* this component must be a constructed type */ + /* XXX add any new universal constructed type here */ + if (tag & SEC_ASN1_CONSTRUCTED) { + *match = PR_TRUE; + return SECSuccess; + } + break; + + default: + /* this component must be a primitive type */ + if (!(tag & SEC_ASN1_CONSTRUCTED)) { + *match = PR_TRUE; + return SECSuccess; + } + break; + } + break; + + default: + /* for all other classes, we check the method based on the template */ + if ((unsigned char)(kind & SEC_ASN1_METHOD_MASK) == + (tag & SEC_ASN1_METHOD_MASK)) { + *match = PR_TRUE; + return SECSuccess; + } + /* method does not match between template and component */ + break; + } + + *match = PR_FALSE; + return SECSuccess; +} + +#ifdef DEBUG + +static SECStatus +CheckSequenceTemplate(const SEC_ASN1Template* sequenceTemplate) +{ + SECStatus rv = SECSuccess; + const SEC_ASN1Template* sequenceEntry = NULL; + unsigned long seqIndex = 0; + unsigned long lastEntryIndex = 0; + unsigned long ambiguityIndex = 0; + PRBool foundAmbiguity = PR_FALSE; + + do { + sequenceEntry = &sequenceTemplate[seqIndex++]; + if (sequenceEntry->kind) { + /* ensure that we don't have an optional component of SEC_ASN1_ANY + in the middle of the sequence, since we could not handle it */ + /* XXX this function needs to dig into the subtemplates to find + the next tag */ + if ((PR_FALSE == foundAmbiguity) && + (sequenceEntry->kind & SEC_ASN1_OPTIONAL) && + (sequenceEntry->kind & SEC_ASN1_ANY)) { + foundAmbiguity = PR_TRUE; + ambiguityIndex = seqIndex - 1; + } + } + } while (sequenceEntry->kind); + + lastEntryIndex = seqIndex - 2; + + if (PR_FALSE != foundAmbiguity) { + if (ambiguityIndex < lastEntryIndex) { + /* ambiguity can only be tolerated on the last entry */ + PORT_SetError(SEC_ERROR_BAD_TEMPLATE); + rv = SECFailure; + } + } + + /* XXX also enforce ASN.1 requirement that tags be + distinct for consecutive optional components */ + + return rv; +} + +#endif + +static SECStatus DecodeItem(void* dest, + const SEC_ASN1Template* templateEntry, + SECItem* src, PLArenaPool* arena, PRBool checkTag); + +static SECStatus +DecodeSequence(void* dest, + const SEC_ASN1Template* templateEntry, + SECItem* src, PLArenaPool* arena) +{ + SECStatus rv = SECSuccess; + SECItem source; + SECItem sequence; + const SEC_ASN1Template* sequenceTemplate = &(templateEntry[1]); + const SEC_ASN1Template* sequenceEntry = NULL; + unsigned long seqindex = 0; + +#ifdef DEBUG + /* for a sequence, we need to validate the template. */ + rv = CheckSequenceTemplate(sequenceTemplate); +#endif + + source = *src; + + /* get the sequence */ + if (SECSuccess == rv) { + rv = GetItem(&source, &sequence, PR_FALSE); + } + + /* process it */ + if (SECSuccess == rv) + do { + sequenceEntry = &sequenceTemplate[seqindex++]; + if ((sequenceEntry && sequenceEntry->kind) && + (sequenceEntry->kind != SEC_ASN1_SKIP_REST)) { + rv = DecodeItem(dest, sequenceEntry, &sequence, arena, PR_TRUE); + } + } while ((SECSuccess == rv) && + (sequenceEntry->kind && + sequenceEntry->kind != SEC_ASN1_SKIP_REST)); + /* we should have consumed all the bytes in the sequence by now + unless the caller doesn't care about the rest of the sequence */ + if (SECSuccess == rv && sequence.len && + sequenceEntry && sequenceEntry->kind != SEC_ASN1_SKIP_REST) { + /* it isn't 100% clear whether this is a bad DER or a bad template. + The problem is that logically, they don't match - there is extra + data in the DER that the template doesn't know about */ + PORT_SetError(SEC_ERROR_BAD_DER); + rv = SECFailure; + } + + return rv; +} + +static SECStatus +DecodeInline(void* dest, + const SEC_ASN1Template* templateEntry, + SECItem* src, PLArenaPool* arena, PRBool checkTag) +{ + const SEC_ASN1Template* inlineTemplate = + SEC_ASN1GetSubtemplate(templateEntry, dest, PR_FALSE); + return DecodeItem((void*)((char*)dest + templateEntry->offset), + inlineTemplate, src, arena, checkTag); +} + +static SECStatus +DecodePointer(void* dest, + const SEC_ASN1Template* templateEntry, + SECItem* src, PLArenaPool* arena, PRBool checkTag) +{ + const SEC_ASN1Template* ptrTemplate = + SEC_ASN1GetSubtemplate(templateEntry, dest, PR_FALSE); + if (!ptrTemplate) { + PORT_SetError(SEC_ERROR_INVALID_ARGS); + return SECFailure; + } + void* subdata = PORT_ArenaZAlloc(arena, ptrTemplate->size); + *(void**)((char*)dest + templateEntry->offset) = subdata; + if (subdata) { + return DecodeItem(subdata, ptrTemplate, src, arena, checkTag); + } else { + PORT_SetError(SEC_ERROR_NO_MEMORY); + return SECFailure; + } +} + +static SECStatus +DecodeImplicit(void* dest, + const SEC_ASN1Template* templateEntry, + SECItem* src, PLArenaPool* arena) +{ + if (templateEntry->kind & SEC_ASN1_POINTER) { + return DecodePointer((void*)((char*)dest), + templateEntry, src, arena, PR_FALSE); + } else { + return DecodeInline((void*)((char*)dest), + templateEntry, src, arena, PR_FALSE); + } +} + +static SECStatus +DecodeChoice(void* dest, + const SEC_ASN1Template* templateEntry, + SECItem* src, PLArenaPool* arena) +{ + SECStatus rv = SECSuccess; + SECItem choice; + const SEC_ASN1Template* choiceTemplate = &(templateEntry[1]); + const SEC_ASN1Template* choiceEntry = NULL; + unsigned long choiceindex = 0; + + /* XXX for a choice component, we should validate the template to make + sure the tags are distinct, in debug builds. This hasn't been + implemented yet */ + /* rv = CheckChoiceTemplate(sequenceTemplate); */ + + /* process it */ + do { + choice = *src; + choiceEntry = &choiceTemplate[choiceindex++]; + if (choiceEntry->kind) { + rv = DecodeItem(dest, choiceEntry, &choice, arena, PR_TRUE); + } + } while ((SECFailure == rv) && (choiceEntry->kind)); + + if (SECFailure == rv) { + /* the component didn't match any of the choices */ + PORT_SetError(SEC_ERROR_BAD_DER); + } else { + /* set the type in the union here */ + int* which = (int*)((char*)dest + templateEntry->offset); + *which = (int)choiceEntry->size; + } + + /* we should have consumed all the bytes by now */ + /* fail if we have not */ + if (SECSuccess == rv && choice.len) { + /* there is extra data that isn't listed in the template */ + PORT_SetError(SEC_ERROR_BAD_DER); + rv = SECFailure; + } + return rv; +} + +static SECStatus +DecodeGroup(void* dest, + const SEC_ASN1Template* templateEntry, + SECItem* src, PLArenaPool* arena) +{ + SECStatus rv = SECSuccess; + SECItem source; + SECItem group; + PRUint32 totalEntries = 0; + PRUint32 entryIndex = 0; + void** entries = NULL; + + const SEC_ASN1Template* subTemplate = + SEC_ASN1GetSubtemplate(templateEntry, dest, PR_FALSE); + + source = *src; + + /* get the group */ + if (SECSuccess == rv) { + rv = GetItem(&source, &group, PR_FALSE); + } + + /* XXX we should check the subtemplate in debug builds */ + if (SECSuccess == rv) { + /* first, count the number of entries. Benchmarking showed that this + counting pass is more efficient than trying to allocate entries as + we read the DER, even if allocating many entries at a time + */ + SECItem counter = group; + do { + SECItem anitem; + rv = GetItem(&counter, &anitem, PR_TRUE); + if (SECSuccess == rv && (anitem.len)) { + totalEntries++; + } + } while ((SECSuccess == rv) && (counter.len)); + + if (SECSuccess == rv) { + /* allocate room for pointer array and entries */ + /* we want to allocate the array even if there is 0 entry */ + entries = (void**)PORT_ArenaZAlloc(arena, sizeof(void*) * (totalEntries + 1) + /* the extra one is for NULL termination */ + subTemplate->size * totalEntries); + + if (entries) { + entries[totalEntries] = NULL; /* terminate the array */ + } else { + PORT_SetError(SEC_ERROR_NO_MEMORY); + rv = SECFailure; + } + if (SECSuccess == rv) { + void* entriesData = (unsigned char*)entries + (unsigned long)(sizeof(void*) * (totalEntries + 1)); + /* and fix the pointers in the array */ + PRUint32 entriesIndex = 0; + for (entriesIndex = 0; entriesIndex < totalEntries; entriesIndex++) { + entries[entriesIndex] = + (char*)entriesData + (subTemplate->size * entriesIndex); + } + } + } + } + + if (SECSuccess == rv && totalEntries) + do { + if (!(entryIndex < totalEntries)) { + rv = SECFailure; + break; + } + rv = DecodeItem(entries[entryIndex++], subTemplate, &group, arena, PR_TRUE); + } while ((SECSuccess == rv) && (group.len)); + /* we should be at the end of the set by now */ + /* save the entries where requested */ + memcpy(((char*)dest + templateEntry->offset), &entries, sizeof(void**)); + + return rv; +} + +static SECStatus +DecodeExplicit(void* dest, + const SEC_ASN1Template* templateEntry, + SECItem* src, PLArenaPool* arena) +{ + SECStatus rv = SECSuccess; + SECItem subItem; + SECItem constructed = *src; + + rv = GetItem(&constructed, &subItem, PR_FALSE); + + if (SECSuccess == rv) { + if (templateEntry->kind & SEC_ASN1_POINTER) { + rv = DecodePointer(dest, templateEntry, &subItem, arena, PR_TRUE); + } else { + rv = DecodeInline(dest, templateEntry, &subItem, arena, PR_TRUE); + } + } + + return rv; +} + +/* new decoder implementation. This is a recursive function */ + +static SECStatus +DecodeItem(void* dest, + const SEC_ASN1Template* templateEntry, + SECItem* src, PLArenaPool* arena, PRBool checkTag) +{ + SECStatus rv = SECSuccess; + SECItem temp; + SECItem mark = { siBuffer, NULL, 0 }; + PRBool pop = PR_FALSE; + PRBool decode = PR_TRUE; + PRBool save = PR_FALSE; + unsigned long kind; + PRBool match = PR_TRUE; + + PR_ASSERT(src && dest && templateEntry && arena); +#if 0 + if (!src || !dest || !templateEntry || !arena) + { + PORT_SetError(SEC_ERROR_INVALID_ARGS); + rv = SECFailure; + } +#endif + + if (SECSuccess == rv) { + /* do the template validation */ + kind = templateEntry->kind; + if (!kind) { + PORT_SetError(SEC_ERROR_BAD_TEMPLATE); + rv = SECFailure; + } + } + + if (SECSuccess == rv) { +#ifdef DEBUG + if (kind & SEC_ASN1_DEBUG_BREAK) { + /* when debugging the decoder or a template that fails to + decode, put SEC_ASN1_DEBUG in the component that gives you + trouble. The decoder will then get to this block and assert. + If you want to debug the rest of the code, you can set a + breakpoint and set dontassert to PR_TRUE, which will let + you skip over the assert and continue the debugging session + past it. */ + PRBool dontassert = PR_FALSE; + PR_ASSERT(dontassert); /* set bkpoint here & set dontassert*/ + } +#endif + + if ((kind & SEC_ASN1_SKIP) || + (kind & SEC_ASN1_SAVE)) { + /* if skipping or saving this component, don't decode it */ + decode = PR_FALSE; + } + + if (kind & (SEC_ASN1_SAVE | SEC_ASN1_OPTIONAL)) { + /* if saving this component, or if it is optional, we may not want to + move past it, so save the position in case we have to rewind */ + mark = *src; + if (kind & SEC_ASN1_SAVE) { + save = PR_TRUE; + if (0 == (kind & SEC_ASN1_SKIP)) { + /* we will for sure have to rewind when saving this + component and not skipping it. This is true for all + legacy uses of SEC_ASN1_SAVE where the following entry + in the template would causes the same component to be + processed again */ + pop = PR_TRUE; + } + } + } + + rv = GetItem(src, &temp, PR_TRUE); + } + + if (SECSuccess == rv) { + /* now check if the component matches what we expect in the template */ + + if (PR_TRUE == checkTag) + + { + rv = MatchComponentType(templateEntry, &temp, &match, dest); + } + + if ((SECSuccess == rv) && (PR_TRUE != match)) { + if (kind & SEC_ASN1_OPTIONAL) { + + /* the optional component is missing. This is not fatal. */ + /* Rewind, don't decode, and don't save */ + pop = PR_TRUE; + decode = PR_FALSE; + save = PR_FALSE; + } else { + /* a required component is missing. abort */ + PORT_SetError(SEC_ERROR_BAD_DER); + rv = SECFailure; + } + } + } + + if ((SECSuccess == rv) && (PR_TRUE == decode)) { + /* the order of processing here is is the tricky part */ + /* we start with our special cases */ + /* first, check the component class */ + if (kind & SEC_ASN1_INLINE) { + /* decode inline template */ + rv = DecodeInline(dest, templateEntry, &temp, arena, PR_TRUE); + } + + else if (kind & SEC_ASN1_EXPLICIT) { + rv = DecodeExplicit(dest, templateEntry, &temp, arena); + } else if ((SEC_ASN1_UNIVERSAL != (kind & SEC_ASN1_CLASS_MASK)) && + + (!(kind & SEC_ASN1_EXPLICIT))) { + + /* decode implicitly tagged components */ + rv = DecodeImplicit(dest, templateEntry, &temp, arena); + } else if (kind & SEC_ASN1_POINTER) { + rv = DecodePointer(dest, templateEntry, &temp, arena, PR_TRUE); + } else if (kind & SEC_ASN1_CHOICE) { + rv = DecodeChoice(dest, templateEntry, &temp, arena); + } else if (kind & SEC_ASN1_ANY) { + /* catch-all ANY type, don't decode */ + save = PR_TRUE; + if (kind & SEC_ASN1_INNER) { + /* skip the tag and length */ + SECItem newtemp = temp; + rv = GetItem(&newtemp, &temp, PR_FALSE); + } + } else if (kind & SEC_ASN1_GROUP) { + if ((SEC_ASN1_SEQUENCE == (kind & SEC_ASN1_TAGNUM_MASK)) || + (SEC_ASN1_SET == (kind & SEC_ASN1_TAGNUM_MASK))) { + rv = DecodeGroup(dest, templateEntry, &temp, arena); + } else { + /* a group can only be a SET OF or SEQUENCE OF */ + PORT_SetError(SEC_ERROR_BAD_TEMPLATE); + rv = SECFailure; + } + } else if (SEC_ASN1_SEQUENCE == (kind & SEC_ASN1_TAGNUM_MASK)) { + /* plain SEQUENCE */ + rv = DecodeSequence(dest, templateEntry, &temp, arena); + } else { + /* handle all other types as "save" */ + /* we should only get here for primitive universal types */ + SECItem newtemp = temp; + rv = GetItem(&newtemp, &temp, PR_FALSE); + save = PR_TRUE; + if ((SECSuccess == rv) && + SEC_ASN1_UNIVERSAL == (kind & SEC_ASN1_CLASS_MASK)) { + unsigned long tagnum = kind & SEC_ASN1_TAGNUM_MASK; + if (temp.len == 0 && (tagnum == SEC_ASN1_BOOLEAN || + tagnum == SEC_ASN1_INTEGER || + tagnum == SEC_ASN1_BIT_STRING || + tagnum == SEC_ASN1_OBJECT_ID || + tagnum == SEC_ASN1_ENUMERATED || + tagnum == SEC_ASN1_UTC_TIME || + tagnum == SEC_ASN1_GENERALIZED_TIME)) { + /* these types MUST have at least one content octet */ + PORT_SetError(SEC_ERROR_BAD_DER); + rv = SECFailure; + } else + switch (tagnum) { + /* special cases of primitive types */ + case SEC_ASN1_INTEGER: { + SECItem* destItem = (SECItem*)((char*)dest + + templateEntry->offset); + if (destItem && (siUnsignedInteger == destItem->type)) { + /* A leading 0 is only allowed when a value + * would otherwise be interpreted as negative. */ + if (temp.len > 1 && temp.data[0] == 0) { + temp.data++; + temp.len--; + if (!(temp.data[0] & 0x80)) { + PORT_SetError(SEC_ERROR_BAD_DER); + rv = SECFailure; + } + } + } + break; + } + + case SEC_ASN1_BIT_STRING: { + /* Can't be 8 or more spare bits, or any spare bits + * if there are no octets. */ + if (temp.data[0] >= 8 || (temp.data[0] > 0 && temp.len == 1)) { + PORT_SetError(SEC_ERROR_BAD_DER); + rv = SECFailure; + break; + } + /* change the length in the SECItem to be the number + of bits */ + temp.len = (temp.len - 1) * 8 - (temp.data[0] & 0x7); + temp.data++; + break; + } + + default: { + break; + } + } + } + } + } + + if ((SECSuccess == rv) && (PR_TRUE == save)) { + SECItem* destItem = (SECItem*)((char*)dest + templateEntry->offset); + if (destItem) { + /* we leave the type alone in the destination SECItem. + If part of the destination was allocated by the decoder, in + cases of POINTER, SET OF and SEQUENCE OF, then type is set to + siBuffer due to the use of PORT_ArenaZAlloc*/ + destItem->data = temp.len ? temp.data : NULL; + destItem->len = temp.len; + } else { + PORT_SetError(SEC_ERROR_INVALID_ARGS); + rv = SECFailure; + } + } + + if (PR_TRUE == pop) { + /* we don't want to move ahead, so restore the position */ + *src = mark; + } + return rv; +} + +/* the function below is the public one */ + +SECStatus +SEC_QuickDERDecodeItem(PLArenaPool* arena, void* dest, + const SEC_ASN1Template* templateEntry, + const SECItem* src) +{ + SECStatus rv = SECSuccess; + SECItem newsrc; + + if (!arena || !templateEntry || !src) { + PORT_SetError(SEC_ERROR_INVALID_ARGS); + rv = SECFailure; + } + + if (SECSuccess == rv) { + newsrc = *src; + rv = DecodeItem(dest, templateEntry, &newsrc, arena, PR_TRUE); + if (SECSuccess == rv && newsrc.len) { + rv = SECFailure; + PORT_SetError(SEC_ERROR_EXTRA_INPUT); + } + } + + return rv; +} |