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Decodes the Name Constraints certificate extension on the CA cert

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and checks the names on the peer cert, rejecting it if invalid
based on the name.
This commit is contained in:
John Safranek
2014-04-28 11:03:24 -07:00
parent 8d8fca67c3
commit 618d282d94
5 changed files with 407 additions and 1 deletions
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366
ctaocrypt/src/asn.c
View File

@@ -1272,6 +1272,11 @@ void InitDecodedCert(DecodedCert* cert, byte* source, word32 inSz, void* heap)
cert->subjectCNLen = 0;
cert->subjectCNStored = 0;
cert->altNames = NULL;
#ifndef IGNORE_NAME_CONSTRAINTS
cert->altEmailNames = NULL;
cert->permittedNames = NULL;
cert->excludedNames = NULL;
#endif /* IGNORE_NAME_CONSTRAINTS */
cert->issuer[0] = '\0';
cert->subject[0] = '\0';
cert->source = source; /* don't own */
@@ -1341,6 +1346,9 @@ void InitDecodedCert(DecodedCert* cert, byte* source, word32 inSz, void* heap)
cert->extSubjKeyIdSrc = NULL;
cert->extSubjKeyIdSz = 0;
#endif /* OPENSSL_EXTRA */
#if defined(OPENSSL_EXTRA) || !defined(IGNORE_NAME_CONSTRAINTS)
cert->extNameConstraintSet = 0;
#endif /* OPENSSL_EXTRA || !IGNORE_NAME_CONSTRAINTS */
#ifdef HAVE_ECC
cert->pkCurveOID = 0;
#endif /* HAVE_ECC */
@@ -1372,6 +1380,22 @@ void FreeAltNames(DNS_entry* altNames, void* heap)
}
}
#ifndef IGNORE_NAME_CONSTRAINTS
void FreeNameSubtrees(Base_entry* names, void* heap)
{
(void)heap;
while (names) {
Base_entry* tmp = names->next;
XFREE(names->name, heap, DYNAMIC_TYPE_ALTNAME);
XFREE(names, heap, DYNAMIC_TYPE_ALTNAME);
names = tmp;
}
}
#endif /* IGNORE_NAME_CONSTRAINTS */
void FreeDecodedCert(DecodedCert* cert)
{
@@ -1381,6 +1405,14 @@ void FreeDecodedCert(DecodedCert* cert)
XFREE(cert->publicKey, cert->heap, DYNAMIC_TYPE_PUBLIC_KEY);
if (cert->altNames)
FreeAltNames(cert->altNames, cert->heap);
#ifndef IGNORE_NAME_CONSTRAINTS
if (cert->altEmailNames)
FreeAltNames(cert->altEmailNames, cert->heap);
if (cert->permittedNames)
FreeNameSubtrees(cert->permittedNames, cert->heap);
if (cert->excludedNames)
FreeNameSubtrees(cert->excludedNames, cert->heap);
#endif /* IGNORE_NAME_CONSTRAINTS */
#ifdef CYASSL_SEP
XFREE(cert->deviceType, cert->heap, 0);
XFREE(cert->hwType, cert->heap, 0);
@@ -1863,7 +1895,30 @@ static int GetName(DecodedCert* cert, int nameType)
dName->emailIdx = cert->srcIdx;
dName->emailLen = adv;
#endif /* OPENSSL_EXTRA */
#ifndef IGNORE_NAME_CONSTRAINTS
{
DNS_entry* emailName = NULL;
emailName = (DNS_entry*)XMALLOC(sizeof(DNS_entry),
cert->heap, DYNAMIC_TYPE_ALTNAME);
if (emailName == NULL) {
CYASSL_MSG("\tOut of Memory");
return MEMORY_E;
}
emailName->name = (char*)XMALLOC(adv + 1,
cert->heap, DYNAMIC_TYPE_ALTNAME);
if (emailName->name == NULL) {
CYASSL_MSG("\tOut of Memory");
return MEMORY_E;
}
XMEMCPY(emailName->name,
&cert->source[cert->srcIdx], adv);
emailName->name[adv] = 0;
emailName->next = cert->altEmailNames;
cert->altEmailNames = emailName;
}
#endif /* IGNORE_NAME_CONSTRAINTS */
if (!tooBig) {
XMEMCPY(&full[idx], &cert->source[cert->srcIdx], adv);
idx += adv;
@@ -2870,6 +2925,152 @@ static int ConfirmSignature(const byte* buf, word32 bufSz,
}
#ifndef IGNORE_NAME_CONSTRAINTS
static int MatchBaseName(int type, const char* name, int nameSz,
const char* base, int baseSz)
{
if (base == NULL || baseSz <= 0 || name == NULL || nameSz <= 0 ||
name[0] == '.' || nameSz < baseSz ||
(type != ASN_RFC822_TYPE && type != ASN_DNS_TYPE))
return 0;
/* If an email type, handle special cases where the base is only
* a domain, or is an email address itself. */
if (type == ASN_RFC822_TYPE) {
const char* p = NULL;
int count = 0;
if (base[0] != '.') {
p = base;
count = 0;
/* find the '@' in the base */
while (*p != '@' && count < baseSz) {
count++;
p++;
}
/* No '@' in base, reset p to NULL */
if (count >= baseSz)
p = NULL;
}
if (p == NULL) {
/* Base isn't an email address, it is a domain name,
* wind the name forward one character past its '@'. */
p = name;
count = 0;
while (*p != '@' && count < baseSz) {
count++;
p++;
}
if (count < baseSz && *p == '@') {
name = p + 1;
nameSz -= count + 1;
}
}
}
if ((type == ASN_DNS_TYPE || type == ASN_RFC822_TYPE) && base[0] == '.') {
int szAdjust = nameSz - baseSz;
name += szAdjust;
nameSz -= szAdjust;
}
while (nameSz > 0) {
if (XTOLOWER(*name++) != XTOLOWER(*base++))
return 0;
nameSz--;
}
return 1;
}
static int ConfirmNameConstraints(Signer* signer, DecodedCert* cert)
{
if (signer == NULL || cert == NULL)
return 0;
/* Check against the excluded list */
if (signer->excludedNames) {
Base_entry* base = signer->excludedNames;
while (base != NULL) {
if (base->type == ASN_DNS_TYPE) {
DNS_entry* name = cert->altNames;
while (name != NULL) {
if (MatchBaseName(ASN_DNS_TYPE,
name->name, (int)XSTRLEN(name->name),
base->name, (int)XSTRLEN(base->name)))
return 0;
name = name->next;
}
}
else if (base->type == ASN_RFC822_TYPE) {
DNS_entry* name = cert->altEmailNames;
while (name != NULL) {
if (MatchBaseName(ASN_RFC822_TYPE,
name->name, (int)XSTRLEN(name->name),
base->name, (int)XSTRLEN(base->name)))
return 0;
name = name->next;
}
}
base = base->next;
}
}
/* Check against the permitted list */
if (signer->permittedNames != NULL) {
int needDns = 0;
int matchDns = 0;
int needEmail = 0;
int matchEmail = 0;
Base_entry* base = signer->permittedNames;
while (base != NULL) {
if (base->type == ASN_DNS_TYPE) {
DNS_entry* name = cert->altNames;
if (name != NULL)
needDns = 1;
while (name != NULL) {
matchDns = MatchBaseName(ASN_DNS_TYPE,
name->name, (int)XSTRLEN(name->name),
base->name, (int)XSTRLEN(base->name));
name = name->next;
}
}
else if (base->type == ASN_RFC822_TYPE) {
DNS_entry* name = cert->altEmailNames;
if (name != NULL)
needEmail = 1;
while (name != NULL) {
matchEmail = MatchBaseName(ASN_DNS_TYPE,
name->name, (int)XSTRLEN(name->name),
base->name, (int)XSTRLEN(base->name));
name = name->next;
}
}
base = base->next;
}
if ((needDns && !matchDns) || (needEmail && !matchEmail))
return 0;
}
return 1;
}
#endif /* IGNORE_NAME_CONSTRAINTS */
static int DecodeAltNames(byte* input, int sz, DecodedCert* cert)
{
word32 idx = 0;
@@ -2924,6 +3125,43 @@ static int DecodeAltNames(byte* input, int sz, DecodedCert* cert)
length -= strLen;
idx += strLen;
}
#ifndef IGNORE_NAME_CONSTRAINTS
else if (b == (ASN_CONTEXT_SPECIFIC | ASN_RFC822_TYPE)) {
DNS_entry* emailEntry;
int strLen;
word32 lenStartIdx = idx;
if (GetLength(input, &idx, &strLen, sz) < 0) {
CYASSL_MSG("\tfail: str length");
return ASN_PARSE_E;
}
length -= (idx - lenStartIdx);
emailEntry = (DNS_entry*)XMALLOC(sizeof(DNS_entry), cert->heap,
DYNAMIC_TYPE_ALTNAME);
if (emailEntry == NULL) {
CYASSL_MSG("\tOut of Memory");
return ASN_PARSE_E;
}
emailEntry->name = (char*)XMALLOC(strLen + 1, cert->heap,
DYNAMIC_TYPE_ALTNAME);
if (emailEntry->name == NULL) {
CYASSL_MSG("\tOut of Memory");
XFREE(emailEntry, cert->heap, DYNAMIC_TYPE_ALTNAME);
return ASN_PARSE_E;
}
XMEMCPY(emailEntry->name, &input[idx], strLen);
emailEntry->name[strLen] = '\0';
emailEntry->next = cert->altEmailNames;
cert->altEmailNames = emailEntry;
length -= strLen;
idx += strLen;
}
#endif /* IGNORE_NAME_CONSTRAINTS */
#ifdef CYASSL_SEP
else if (b == (ASN_CONTEXT_SPECIFIC | ASN_CONSTRUCTED | ASN_OTHER_TYPE))
{
@@ -3329,7 +3567,7 @@ static int DecodeExtKeyUsage(byte* input, int sz, DecodedCert* cert)
CYASSL_ENTER("DecodeExtKeyUsage");
if (GetSequence(input, &idx, &length, sz) < 0) {
CYASSL_MSG("\tfail: should be a SEQUENCE\n");
CYASSL_MSG("\tfail: should be a SEQUENCE");
return ASN_PARSE_E;
}
@@ -3366,6 +3604,103 @@ static int DecodeExtKeyUsage(byte* input, int sz, DecodedCert* cert)
}
#ifndef IGNORE_NAME_CONSTRAINTS
static int DecodeSubtree(byte* input, int sz, Base_entry** head, void* heap)
{
word32 idx = 0;
(void)heap;
while (idx < (word32)sz) {
int seqLength, strLength;
word32 nameIdx;
byte b;
if (GetSequence(input, &idx, &seqLength, sz) < 0) {
CYASSL_MSG("\tfail: should be a SEQUENCE");
return ASN_PARSE_E;
}
nameIdx = idx;
b = input[nameIdx++];
if (GetLength(input, &nameIdx, &strLength, sz) <= 0) {
CYASSL_MSG("\tinvalid length");
return ASN_PARSE_E;
}
if (b == (ASN_CONTEXT_SPECIFIC | ASN_DNS_TYPE) ||
b == (ASN_CONTEXT_SPECIFIC | ASN_RFC822_TYPE)) {
Base_entry* entry = (Base_entry*)XMALLOC(sizeof(Base_entry),
heap, DYNAMIC_TYPE_ALTNAME);
if (entry == NULL) {
CYASSL_MSG("allocate error");
return MEMORY_E;
}
entry->name = (char*)XMALLOC(strLength + 1,
heap, DYNAMIC_TYPE_ALTNAME);
if (entry->name == NULL) {
CYASSL_MSG("allocate error");
return MEMORY_E;
}
XMEMCPY(entry->name, &input[nameIdx], strLength);
entry->name[strLength] = '\0';
entry->type = b & 0x0F;
entry->next = *head;
*head = entry;
}
idx += seqLength;
}
return 0;
}
static int DecodeNameConstraints(byte* input, int sz, DecodedCert* cert)
{
word32 idx = 0;
int length = 0;
CYASSL_ENTER("DecodeNameConstraints");
if (GetSequence(input, &idx, &length, sz) < 0) {
CYASSL_MSG("\tfail: should be a SEQUENCE");
return ASN_PARSE_E;
}
while (idx < (word32)sz) {
byte b = input[idx++];
Base_entry** subtree = NULL;
if (GetLength(input, &idx, &length, sz) <= 0) {
CYASSL_MSG("\tinvalid length");
return ASN_PARSE_E;
}
if (b == (ASN_CONTEXT_SPECIFIC | ASN_CONSTRUCTED | 0))
subtree = &cert->permittedNames;
else if (b == (ASN_CONTEXT_SPECIFIC | ASN_CONSTRUCTED | 1))
subtree = &cert->excludedNames;
else {
CYASSL_MSG("\tinvalid subtree");
return ASN_PARSE_E;
}
DecodeSubtree(input + idx, length, subtree, cert->heap);
idx += length;
}
return 0;
}
#endif /* IGNORE_NAME_CONSTRAINTS */
#ifdef CYASSL_SEP
static int DecodeCertPolicy(byte* input, int sz, DecodedCert* cert)
{
@@ -3552,6 +3887,17 @@ static int DecodeCertExtensions(DecodedCert* cert)
return ASN_PARSE_E;
break;
#ifndef IGNORE_NAME_CONSTRAINTS
case NAME_CONS_OID:
cert->extNameConstraintSet = 1;
#ifdef OPENSSL_EXTRA
cert->extNameConstraintCrit = critical;
#endif
if (DecodeNameConstraints(&input[idx], length, cert) < 0)
return ASN_PARSE_E;
break;
#endif /* IGNORE_NAME_CONSTRAINTS */
case INHIBIT_ANY_OID:
CYASSL_MSG("Inhibit anyPolicy extension not supported yet.");
break;
@@ -3714,6 +4060,14 @@ int ParseCertRelative(DecodedCert* cert, int type, int verify, void* cm)
CYASSL_MSG("Confirm signature failed");
return ASN_SIG_CONFIRM_E;
}
#ifndef IGNORE_NAME_CONSTRAINTS
/* check that this cert's name is permitted by the signer's
* name constraints */
if (!ConfirmNameConstraints(ca, cert)) {
CYASSL_MSG("Confirm name constraint failed");
return ASN_NAME_INVALID_E;
}
#endif /* IGNORE_NAME_CONSTRAINTS */
}
else {
/* no signer */
@@ -3743,6 +4097,10 @@ Signer* MakeSigner(void* heap)
signer->publicKey = NULL;
signer->nameLen = 0;
signer->name = NULL;
#ifndef IGNORE_NAME_CONSTRAINTS
signer->permittedNames = NULL;
signer->excludedNames = NULL;
#endif /* IGNORE_NAME_CONSTRAINTS */
signer->next = NULL;
}
(void)heap;
@@ -3756,6 +4114,12 @@ void FreeSigner(Signer* signer, void* heap)
{
XFREE(signer->name, heap, DYNAMIC_TYPE_SUBJECT_CN);
XFREE(signer->publicKey, heap, DYNAMIC_TYPE_PUBLIC_KEY);
#ifndef IGNORE_NAME_CONSTRAINTS
if (signer->permittedNames)
FreeNameSubtrees(signer->permittedNames, heap);
if (signer->excludedNames)
FreeNameSubtrees(signer->excludedNames, heap);
#endif
XFREE(signer, heap, DYNAMIC_TYPE_SIGNER);
(void)heap;

4
ctaocrypt/src/error.c
View File

@@ -351,6 +351,10 @@ void CTaoCryptErrorString(int error, char* buffer)
XSTRNCPY(buffer, "FIPS mode not allowed error", max);
break;
case ASN_NAME_INVALID_E:
XSTRNCPY(buffer, "Name Constraint error", max);
break;
default:
XSTRNCPY(buffer, "unknown error number", max);