in src/crypto/x509/x509_vfy.c [186:523]
int X509_verify_cert(X509_STORE_CTX *ctx)
{
X509 *x, *xtmp, *xtmp2, *chain_ss = NULL;
int bad_chain = 0;
X509_VERIFY_PARAM *param = ctx->param;
int depth, i, ok = 0;
int num, j, retry, trust;
int (*cb) (int xok, X509_STORE_CTX *xctx);
STACK_OF(X509) *sktmp = NULL;
if (ctx->cert == NULL) {
OPENSSL_PUT_ERROR(X509, X509_R_NO_CERT_SET_FOR_US_TO_VERIFY);
ctx->error = X509_V_ERR_INVALID_CALL;
return -1;
}
if (ctx->chain != NULL) {
/*
* This X509_STORE_CTX has already been used to verify a cert. We
* cannot do another one.
*/
OPENSSL_PUT_ERROR(X509, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
ctx->error = X509_V_ERR_INVALID_CALL;
return -1;
}
cb = ctx->verify_cb;
/*
* first we make sure the chain we are going to build is present and that
* the first entry is in place
*/
ctx->chain = sk_X509_new_null();
if (ctx->chain == NULL || !sk_X509_push(ctx->chain, ctx->cert)) {
OPENSSL_PUT_ERROR(X509, ERR_R_MALLOC_FAILURE);
ctx->error = X509_V_ERR_OUT_OF_MEM;
goto end;
}
X509_up_ref(ctx->cert);
ctx->last_untrusted = 1;
/* We use a temporary STACK so we can chop and hack at it. */
if (ctx->untrusted != NULL
&& (sktmp = sk_X509_dup(ctx->untrusted)) == NULL) {
OPENSSL_PUT_ERROR(X509, ERR_R_MALLOC_FAILURE);
ctx->error = X509_V_ERR_OUT_OF_MEM;
goto end;
}
num = sk_X509_num(ctx->chain);
x = sk_X509_value(ctx->chain, num - 1);
depth = param->depth;
for (;;) {
/* If we have enough, we break */
if (depth < num)
break; /* FIXME: If this happens, we should take
* note of it and, if appropriate, use the
* X509_V_ERR_CERT_CHAIN_TOO_LONG error code
* later. */
int is_self_signed;
if (!cert_self_signed(x, &is_self_signed)) {
ctx->error = X509_V_ERR_INVALID_EXTENSION;
goto end;
}
/* If we are self signed, we break */
if (is_self_signed)
break;
/*
* If asked see if we can find issuer in trusted store first
*/
if (ctx->param->flags & X509_V_FLAG_TRUSTED_FIRST) {
ok = ctx->get_issuer(&xtmp, ctx, x);
if (ok < 0) {
ctx->error = X509_V_ERR_STORE_LOOKUP;
goto end;
}
/*
* If successful for now free up cert so it will be picked up
* again later.
*/
if (ok > 0) {
X509_free(xtmp);
break;
}
}
/* If we were passed a cert chain, use it first */
if (sktmp != NULL) {
xtmp = find_issuer(ctx, sktmp, x);
if (xtmp != NULL) {
if (!sk_X509_push(ctx->chain, xtmp)) {
OPENSSL_PUT_ERROR(X509, ERR_R_MALLOC_FAILURE);
ctx->error = X509_V_ERR_OUT_OF_MEM;
ok = 0;
goto end;
}
X509_up_ref(xtmp);
(void)sk_X509_delete_ptr(sktmp, xtmp);
ctx->last_untrusted++;
x = xtmp;
num++;
/*
* reparse the full chain for the next one
*/
continue;
}
}
break;
}
/* Remember how many untrusted certs we have */
j = num;
/*
* at this point, chain should contain a list of untrusted certificates.
* We now need to add at least one trusted one, if possible, otherwise we
* complain.
*/
do {
/*
* Examine last certificate in chain and see if it is self signed.
*/
i = sk_X509_num(ctx->chain);
x = sk_X509_value(ctx->chain, i - 1);
int is_self_signed;
if (!cert_self_signed(x, &is_self_signed)) {
ctx->error = X509_V_ERR_INVALID_EXTENSION;
goto end;
}
if (is_self_signed) {
/* we have a self signed certificate */
if (sk_X509_num(ctx->chain) == 1) {
/*
* We have a single self signed certificate: see if we can
* find it in the store. We must have an exact match to avoid
* possible impersonation.
*/
ok = ctx->get_issuer(&xtmp, ctx, x);
if ((ok <= 0) || X509_cmp(x, xtmp)) {
ctx->error = X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT;
ctx->current_cert = x;
ctx->error_depth = i - 1;
if (ok == 1)
X509_free(xtmp);
bad_chain = 1;
ok = cb(0, ctx);
if (!ok)
goto end;
} else {
/*
* We have a match: replace certificate with store
* version so we get any trust settings.
*/
X509_free(x);
x = xtmp;
(void)sk_X509_set(ctx->chain, i - 1, x);
ctx->last_untrusted = 0;
}
} else {
/*
* extract and save self signed certificate for later use
*/
chain_ss = sk_X509_pop(ctx->chain);
ctx->last_untrusted--;
num--;
j--;
x = sk_X509_value(ctx->chain, num - 1);
}
}
/* We now lookup certs from the certificate store */
for (;;) {
/* If we have enough, we break */
if (depth < num)
break;
if (!cert_self_signed(x, &is_self_signed)) {
ctx->error = X509_V_ERR_INVALID_EXTENSION;
goto end;
}
/* If we are self signed, we break */
if (is_self_signed)
break;
ok = ctx->get_issuer(&xtmp, ctx, x);
if (ok < 0) {
ctx->error = X509_V_ERR_STORE_LOOKUP;
goto end;
}
if (ok == 0)
break;
x = xtmp;
if (!sk_X509_push(ctx->chain, x)) {
X509_free(xtmp);
OPENSSL_PUT_ERROR(X509, ERR_R_MALLOC_FAILURE);
ctx->error = X509_V_ERR_OUT_OF_MEM;
ok = 0;
goto end;
}
num++;
}
/* we now have our chain, lets check it... */
trust = check_trust(ctx);
/* If explicitly rejected error */
if (trust == X509_TRUST_REJECTED) {
ok = 0;
goto end;
}
/*
* If it's not explicitly trusted then check if there is an alternative
* chain that could be used. We only do this if we haven't already
* checked via TRUSTED_FIRST and the user hasn't switched off alternate
* chain checking
*/
retry = 0;
if (trust != X509_TRUST_TRUSTED
&& !(ctx->param->flags & X509_V_FLAG_TRUSTED_FIRST)
&& !(ctx->param->flags & X509_V_FLAG_NO_ALT_CHAINS)) {
while (j-- > 1) {
xtmp2 = sk_X509_value(ctx->chain, j - 1);
ok = ctx->get_issuer(&xtmp, ctx, xtmp2);
if (ok < 0)
goto end;
/* Check if we found an alternate chain */
if (ok > 0) {
/*
* Free up the found cert we'll add it again later
*/
X509_free(xtmp);
/*
* Dump all the certs above this point - we've found an
* alternate chain
*/
while (num > j) {
xtmp = sk_X509_pop(ctx->chain);
X509_free(xtmp);
num--;
}
ctx->last_untrusted = sk_X509_num(ctx->chain);
retry = 1;
break;
}
}
}
} while (retry);
/*
* If not explicitly trusted then indicate error unless it's a single
* self signed certificate in which case we've indicated an error already
* and set bad_chain == 1
*/
if (trust != X509_TRUST_TRUSTED && !bad_chain) {
if ((chain_ss == NULL) || !ctx->check_issued(ctx, x, chain_ss)) {
if (ctx->last_untrusted >= num)
ctx->error = X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY;
else
ctx->error = X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT;
ctx->current_cert = x;
} else {
sk_X509_push(ctx->chain, chain_ss);
num++;
ctx->last_untrusted = num;
ctx->current_cert = chain_ss;
ctx->error = X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN;
chain_ss = NULL;
}
ctx->error_depth = num - 1;
bad_chain = 1;
ok = cb(0, ctx);
if (!ok)
goto end;
}
/* We have the chain complete: now we need to check its purpose */
ok = check_chain_extensions(ctx);
if (!ok)
goto end;
ok = check_id(ctx);
if (!ok)
goto end;
/*
* Check revocation status: we do this after copying parameters because
* they may be needed for CRL signature verification.
*/
ok = ctx->check_revocation(ctx);
if (!ok)
goto end;
int err = X509_chain_check_suiteb(&ctx->error_depth, NULL, ctx->chain,
ctx->param->flags);
if (err != X509_V_OK) {
ctx->error = err;
ctx->current_cert = sk_X509_value(ctx->chain, ctx->error_depth);
ok = cb(0, ctx);
if (!ok)
goto end;
}
/* At this point, we have a chain and need to verify it */
if (ctx->verify != NULL)
ok = ctx->verify(ctx);
else
ok = internal_verify(ctx);
if (!ok)
goto end;
/* Check name constraints */
ok = check_name_constraints(ctx);
if (!ok)
goto end;
/* If we get this far evaluate policies */
if (!bad_chain && (ctx->param->flags & X509_V_FLAG_POLICY_CHECK))
ok = ctx->check_policy(ctx);
end:
if (sktmp != NULL)
sk_X509_free(sktmp);
if (chain_ss != NULL)
X509_free(chain_ss);
/* Safety net, error returns must set ctx->error */
if (ok <= 0 && ctx->error == X509_V_OK)
ctx->error = X509_V_ERR_UNSPECIFIED;
return ok;
}