SCT_CTX *SCT_CTX_new(void)
{
- SCT_CTX *sctx = OPENSSL_zalloc(sizeof(SCT_CTX));
+ SCT_CTX *sctx = OPENSSL_zalloc(sizeof(*sctx));
+
if (sctx == NULL)
CTerr(CT_F_SCT_CTX_NEW, ERR_R_MALLOC_FAILURE);
+
return sctx;
}
OPENSSL_free(sctx);
}
-/* retrieve extension index checking for duplicates */
-static int sct_get_ext(X509 *cert, int nid)
+/*
+ * Finds the index of the first extension with the given NID in cert.
+ * If there is more than one extension with that NID, *is_duplicated is set to
+ * 1, otherwise 0 (unless it is NULL).
+ */
+static int ct_x509_get_ext(X509 *cert, int nid, int *is_duplicated)
{
- int rv = X509_get_ext_by_NID(cert, nid, -1);
- if (rv >= 0 && X509_get_ext_by_NID(cert, nid, rv) >= 0)
- return -2;
- return rv;
+ int ret = X509_get_ext_by_NID(cert, nid, -1);
+
+ if (is_duplicated != NULL)
+ *is_duplicated = ret >= 0 && X509_get_ext_by_NID(cert, nid, ret) >= 0;
+
+ return ret;
}
/*
- * modify certificate by deleting extensions, copying issuer
- * and AKID if necessary.
+ * Modifies a certificate by deleting extensions and copying the issuer and
+ * AKID from the presigner certificate, if necessary.
+ * Returns 1 on success, 0 otherwise.
*/
-static int sct_cert_fixup(X509 *cert, X509 *presigner)
+__owur static int ct_x509_cert_fixup(X509 *cert, X509 *presigner)
{
int preidx, certidx;
+ int pre_akid_ext_is_dup, cert_akid_ext_is_dup;
+
if (presigner == NULL)
return 1;
- preidx = sct_get_ext(presigner, NID_authority_key_identifier);
- certidx = sct_get_ext(cert, NID_authority_key_identifier);
- /* Invalid certificate if duplicate */
- if (preidx == -2 || certidx == -2)
+
+ preidx = ct_x509_get_ext(presigner, NID_authority_key_identifier,
+ &pre_akid_ext_is_dup);
+ certidx = ct_x509_get_ext(cert, NID_authority_key_identifier,
+ &cert_akid_ext_is_dup);
+
+ /* An error occurred whilst searching for the extension */
+ if (preidx < -1 || certidx < -1)
+ return 0;
+ /* Invalid certificate if they contain duplicate extensions */
+ if (pre_akid_ext_is_dup || cert_akid_ext_is_dup)
return 0;
/* AKID must be present in both certificate or absent in both */
if (preidx >= 0 && certidx == -1)
X509_EXTENSION *preext = X509_get_ext(presigner, preidx);
X509_EXTENSION *certext = X509_get_ext(cert, certidx);
ASN1_OCTET_STRING *preextdata;
+
/* Should never happen */
if (preext == NULL || certext == NULL)
return 0;
preextdata = X509_EXTENSION_get_data(preext);
- if (preextdata == NULL || !X509_EXTENSION_set_data(certext, preextdata))
+ if (preextdata == NULL ||
+ !X509_EXTENSION_set_data(certext, preextdata))
return 0;
}
return 1;
unsigned char *certder = NULL, *preder = NULL;
X509 *pretmp = NULL;
int certderlen = 0, prederlen = 0;
- int idx = -1, idxp = -1;
- idxp = sct_get_ext(cert, NID_ct_precert_poison);
- /* Duplicate poison */
- if (idxp == -2)
+ int idx = -1;
+ int poison_ext_is_dup, sct_ext_is_dup;
+ int poison_idx = ct_x509_get_ext(cert, NID_ct_precert_poison, &poison_ext_is_dup);
+
+ /* Duplicate poison extensions are present - error */
+ if (poison_ext_is_dup)
goto err;
- /* If no poison store encoding */
- if (idxp == -1) {
- /* If presigner must have poison */
- if (presigner)
+
+ /* If *cert doesn't have a poison extension, it isn't a precert */
+ if (poison_idx == -1) {
+ /* cert isn't a precert, so we shouldn't have a presigner */
+ if (presigner != NULL)
goto err;
+
certderlen = i2d_X509(cert, &certder);
if (certderlen < 0)
goto err;
}
- /* See if have precert scts extension */
- idx = X509_get_ext_by_NID(cert, NID_ct_precert_scts, -1);
- /* Duplicate scts */
- if (idx == -2)
+
+ /* See if cert has a precert SCTs extension */
+ idx = ct_x509_get_ext(cert, NID_ct_precert_scts, &sct_ext_is_dup);
+ /* Duplicate SCT extensions are present - error */
+ if (sct_ext_is_dup)
goto err;
- if (idx >= 0) {
- /* Can't have both poison and scts */
- if (idxp >= 0)
- goto err;
- } else
- idx = idxp;
- if (idx >= 0) {
- X509_EXTENSION *ext;
+
+ if (idx >= 0 && poison_idx >= 0) {
/*
- * Take a copy of certificate so we don't modify passed version
+ * cert can't both contain SCTs (i.e. have an SCT extension) and be a
+ * precert (i.e. have a poison extension).
*/
+ goto err;
+ }
+
+ if (idx == -1) {
+ idx = poison_idx;
+ }
+
+ /*
+ * If either a poison or SCT extension is present, remove it before encoding
+ * cert. This, along with ct_x509_cert_fixup(), gets a TBSCertificate (see
+ * RFC5280) from cert, which is what the CT log signed when it produced the
+ * SCT.
+ */
+ if (idx >= 0) {
+ X509_EXTENSION *ext;
+
+ /* Take a copy of certificate so we don't modify passed version */
pretmp = X509_dup(cert);
if (pretmp == NULL)
goto err;
+
ext = X509_delete_ext(pretmp, idx);
X509_EXTENSION_free(ext);
- if (!sct_cert_fixup(pretmp, presigner))
+
+ if (!ct_x509_cert_fixup(pretmp, presigner))
goto err;
prederlen = i2d_re_X509_tbs(pretmp, &preder);
sctx->prederlen = prederlen;
return 1;
-
- err:
+err:
OPENSSL_free(certder);
OPENSSL_free(preder);
X509_free(pretmp);
return 0;
}
-static int CT_public_key_hash(X509_PUBKEY *pkey, unsigned char **hash,
- size_t *hash_len)
+__owur static int ct_public_key_hash(X509_PUBKEY *pkey, unsigned char **hash,
+ size_t *hash_len)
{
- int ret = -1;
+ int ret = 0;
unsigned char *md = NULL, *der = NULL;
int der_len;
unsigned int md_len;
- if (pkey == NULL)
- goto err;
+
/* Reuse buffer if possible */
if (*hash != NULL && *hash_len >= SHA256_DIGEST_LENGTH) {
md = *hash;
} else {
md = OPENSSL_malloc(SHA256_DIGEST_LENGTH);
if (md == NULL)
- goto err;
+ goto err;
}
/* Calculate key hash */
der_len = i2d_X509_PUBKEY(pkey, &der);
if (der_len <= 0)
goto err;
+
if (!EVP_Digest(der, der_len, md, &md_len, EVP_sha256(), NULL))
goto err;
+
if (md != *hash) {
OPENSSL_free(*hash);
*hash = md;
*hash_len = SHA256_DIGEST_LENGTH;
}
+
md = NULL;
ret = 1;
err:
int SCT_CTX_set1_issuer(SCT_CTX *sctx, const X509 *issuer)
{
- return CT_public_key_hash(X509_get_X509_PUBKEY(issuer), &sctx->ihash,
- &sctx->ihashlen);
+ return SCT_CTX_set1_issuer_pubkey(sctx, X509_get_X509_PUBKEY(issuer));
}
int SCT_CTX_set1_issuer_pubkey(SCT_CTX *sctx, X509_PUBKEY *pubkey)
{
- return CT_public_key_hash(pubkey, &sctx->ihash, &sctx->ihashlen);
+ return ct_public_key_hash(pubkey, &sctx->ihash, &sctx->ihashlen);
}
int SCT_CTX_set1_pubkey(SCT_CTX *sctx, X509_PUBKEY *pubkey)
{
EVP_PKEY *pkey = X509_PUBKEY_get(pubkey);
+
if (pkey == NULL)
return 0;
- if (!CT_public_key_hash(pubkey, &sctx->pkeyhash, &sctx->pkeyhashlen)) {
+ if (!ct_public_key_hash(pubkey, &sctx->pkeyhash, &sctx->pkeyhashlen)) {
EVP_PKEY_free(pkey);
return 0;
}