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crypt32: Only permit v1 or v2 CA certificates without a key usage extension if they're installed locally.

This commit is contained in:
Juan Lang 2009-10-28 17:32:39 -07:00 committed by Alexandre Julliard
parent 7b0297769d
commit 60770fb011
1 changed files with 25 additions and 19 deletions
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44
dlls/crypt32/chain.c
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@ -1082,8 +1082,8 @@ static void dump_element(PCCERT_CONTEXT cert)
dump_extension(&cert->pCertInfo->rgExtension[i]);
}
static BOOL CRYPT_KeyUsageValid(PCCERT_CONTEXT cert, BOOL isRoot, BOOL isCA,
DWORD index)
static BOOL CRYPT_KeyUsageValid(PCertificateChainEngine engine,
PCCERT_CONTEXT cert, BOOL isCA, DWORD index)
{
PCERT_EXTENSION ext;
BOOL ret;
@ -1121,20 +1121,33 @@ static BOOL CRYPT_KeyUsageValid(PCCERT_CONTEXT cert, BOOL isRoot, BOOL isCA,
{
if (!ext)
{
/* MS appears to violate RFC 3280, section 4.2.1.3 (Key Usage)
/* MS appears to violate RFC 5280, section 4.2.1.3 (Key Usage)
* here. Quoting the RFC:
* "This [key usage] extension MUST appear in certificates that
* contain public keys that are used to validate digital signatures
* on other public key certificates or CRLs."
* Most of the test chains' certs do not contain key usage
* extensions, yet are allowed to be CA certs. This appears to
* be common usage too: the root CA in a chain often does not have
* the key usage extension. We are a little more restrictive:
* root certs, which commonly do not have any extensions, are
* allowed to sign certificates without the key usage extension.
* MS appears to accept certs that do not contain key usage
* extensions as CA certs. V1 and V2 certificates did not have
* extensions, and many root certificates are V1 certificates, so
* perhaps this is prudent. On the other hand, MS also accepts V3
* certs without key usage extensions. We are more restrictive:
* we accept locally installed V1 or V2 certs as CA certs.
*/
WARN_(chain)("no key usage extension on a CA cert\n");
ret = isRoot;
ret = FALSE;
if (cert->pCertInfo->dwVersion == CERT_V1 ||
cert->pCertInfo->dwVersion == CERT_V2)
{
PCCERT_CONTEXT localCert = CRYPT_FindCertInStore(
engine->hWorld, cert);
if (localCert)
{
CertFreeCertificateContext(localCert);
ret = TRUE;
}
}
if (!ret)
WARN_(chain)("no key usage extension on a CA cert\n");
}
else
{
@ -1206,19 +1219,12 @@ static void CRYPT_CheckSimpleChain(PCertificateChainEngine engine,
chain->cElement, debugstr_w(filetime_to_str(time)));
for (i = chain->cElement - 1; i >= 0; i--)
{
BOOL isRoot;
if (TRACE_ON(chain))
dump_element(chain->rgpElement[i]->pCertContext);
if (CertVerifyTimeValidity(time,
chain->rgpElement[i]->pCertContext->pCertInfo) != 0)
chain->rgpElement[i]->TrustStatus.dwErrorStatus |=
CERT_TRUST_IS_NOT_TIME_VALID;
if (i == chain->cElement - 1)
isRoot = CRYPT_IsCertificateSelfSigned(
chain->rgpElement[i]->pCertContext);
else
isRoot = FALSE;
if (i != 0)
{
/* Check the signature of the cert this issued */
@ -1255,7 +1261,7 @@ static void CRYPT_CheckSimpleChain(PCertificateChainEngine engine,
chain->rgpElement[i]->TrustStatus.dwErrorStatus |=
CERT_TRUST_INVALID_BASIC_CONSTRAINTS;
}
if (!CRYPT_KeyUsageValid(chain->rgpElement[i]->pCertContext, isRoot,
if (!CRYPT_KeyUsageValid(engine, chain->rgpElement[i]->pCertContext,
constraints.fCA, i))
chain->rgpElement[i]->TrustStatus.dwErrorStatus |=
CERT_TRUST_IS_NOT_VALID_FOR_USAGE;