这与其他问题非常相似，但我所看到的问题要么没有答案，要么也不会问同样的问题。我有一个自签名CA证书，以及使用该CA证书签名的另外两个证书。我很确定证书是正确的，因为'openssl verify'有效：
$ openssl verify -CAfile ca.pem server.pem
server.pem: OK
（以上是从记忆中，我没有在他面前，所以它可能会略微偏离）。
现在我想以编程方式验证证书。我有一个带伪代码的实用函数：
int verify_cert(X509 *cert, X509 *cacert)
{
int ret;
X509_STORE *store;
X509_STORE_CTX *ctx;
store = X509_STORE_new();
X590_STORE_add_cert(store, cacert);
ctx = X509_STORE_CTX_new();
X509_STORE_CTX_init(ctx, store, cert, NULL);
ret = X590_verify_cert(ctx);
/* check for errors and clean up */
}
我的问题是上面的代码总是返回'找不到颁发者证书'。我做错了什么？我相信我正在创建一个新的商店，添加cacert，创建一个新的上下文，并使用指向包含CA的商店的指针将要验证的子证书添加到上下文中。我显然做错了什么，但我不确定是什么。
有什么想法吗？
更新：我知道我可以将这些证书保存到磁盘并使用类似X509_LOOKUP_file之类的东西。我正在寻找一种不会不必要地接触磁盘的解决方案。
答案 0 :(得分：14)
您可以使用常规验证例程（请参阅How do you verify a public key was issued by your private CA?），就像OpenSSL中的-verify函数一样。您需要创建一个查找方法（X509_LOOKUP_METHOD），如X509_LOOKUP_file（），但它使用字符串而不是文件名。 X509_LOOKUP_buffer（）的代码如下。
头文件by_buffer.h：
/* File: by_buffer.h */
#ifndef BY_BUFFER_H
#define BY_BUFFER_H
#include <openssl/x509.h>
#ifdef __cplusplus
extern "C" {
#endif
#define X509_L_BUF_LOAD 1
#define X509_LOOKUP_load_buf(x,name,type) \
X509_LOOKUP_ctrl((x),X509_L_BUF_LOAD,(name),(long)(type),NULL)
X509_LOOKUP_METHOD *X509_LOOKUP_buffer(void);
#ifdef __cplusplus
}
#endif
#endif /* BY_BUFFER_H */
c程序by_buffer.c：
/* by_buffer.c - copied and modified from crypto/x509/by_file.c */
/* Copyright (C) - should be the same as for OpenSSL
*/
#include "by_buffer.h"
#include <stdio.h>
#include <time.h>
#include <errno.h>
#include "../crypto/cryptlib.h"
#include <openssl/lhash.h>
#include <openssl/buffer.h>
#include <openssl/pem.h>
#include <openssl/err.h>
static int by_buffer_ctrl(X509_LOOKUP *ctx, int cmd, const char *argc,
long argl, char **ret);
X509_LOOKUP_METHOD x509_buffer_lookup=
{
"Load buffer into cache",
NULL, /* new */
NULL, /* free */
NULL, /* init */
NULL, /* shutdown */
by_buffer_ctrl, /* ctrl */
NULL, /* get_by_subject */
NULL, /* get_by_issuer_serial */
NULL, /* get_by_fingerprint */
NULL, /* get_by_alias */
};
X509_LOOKUP_METHOD *X509_LOOKUP_buffer(void)
{
return(&x509_buffer_lookup);
}
static int by_buffer_ctrl(X509_LOOKUP *ctx, int cmd, const char *argp, long argl,
char **ret)
{
int ok=0;
char *certBuf;
switch (cmd)
{
case X509_L_BUF_LOAD:
if (argl == X509_FILETYPE_DEFAULT)
{
X509err(X509_F_BY_FILE_CTRL,X509_R_LOADING_DEFAULTS);
}
else
{
if(argl == X509_FILETYPE_PEM)
ok = (X509_load_cert_crl_buf(ctx,argp,
X509_FILETYPE_PEM) != 0);
else
ok = (X509_load_cert_buf(ctx,argp,(int)argl) != 0);
}
break;
}
return(ok);
}
int X509_load_cert_buf(X509_LOOKUP *ctx, const char *certBuf, int type)
{
int ret=0;
BIO *in=NULL;
int i,count=0;
X509 *x=NULL;
if (certBuf == NULL) return(1);
in=BIO_new(BIO_s_mem());
if(in==NULL) goto err;
if (type == X509_FILETYPE_PEM)
{
for (;;)
{
x=PEM_read_bio_X509_AUX(in,NULL,NULL,NULL);
if (x == NULL)
{
if ((ERR_GET_REASON(ERR_peek_last_error()) ==
PEM_R_NO_START_LINE) && (count > 0))
{
ERR_clear_error();
break;
}
else
{
X509err(X509_F_X509_LOAD_CERT_FILE,
ERR_R_PEM_LIB);
goto err;
}
}
i=X509_STORE_add_cert(ctx->store_ctx,x);
if (!i) goto err;
count++;
X509_free(x);
x=NULL;
}
ret=count;
}
else if (type == X509_FILETYPE_ASN1)
{
x=d2i_X509_bio(in,NULL);
if (x == NULL)
{
X509err(X509_F_X509_LOAD_CERT_FILE,ERR_R_ASN1_LIB);
goto err;
}
i=X509_STORE_add_cert(ctx->store_ctx,x);
if (!i) goto err;
ret=i;
}
else
{
X509err(X509_F_X509_LOAD_CERT_FILE,X509_R_BAD_X509_FILETYPE);
goto err;
}
err:
if (x != NULL) X509_free(x);
if (in != NULL) BIO_free(in);
return(ret);
}
int X509_load_crl_buf(X509_LOOKUP *ctx, const char *certBuf, int type)
{
int ret=0;
BIO *in=NULL;
int i,count=0;
X509_CRL *x=NULL;
if (certBuf == NULL) return(1);
//in=BIO_new(BIO_s_file_internal());
in=BIO_new(BIO_s_mem());
if(in==NULL) goto err;
if (type == X509_FILETYPE_PEM)
{
for (;;)
{
x=PEM_read_bio_X509_CRL(in,NULL,NULL,NULL);
if (x == NULL)
{
if ((ERR_GET_REASON(ERR_peek_last_error()) ==
PEM_R_NO_START_LINE) && (count > 0))
{
ERR_clear_error();
break;
}
else
{
X509err(X509_F_X509_LOAD_CRL_FILE,
ERR_R_PEM_LIB);
goto err;
}
}
i=X509_STORE_add_crl(ctx->store_ctx,x);
if (!i) goto err;
count++;
X509_CRL_free(x);
x=NULL;
}
ret=count;
}
else if (type == X509_FILETYPE_ASN1)
{
x=d2i_X509_CRL_bio(in,NULL);
if (x == NULL)
{
X509err(X509_F_X509_LOAD_CRL_FILE,ERR_R_ASN1_LIB);
goto err;
}
i=X509_STORE_add_crl(ctx->store_ctx,x);
if (!i) goto err;
ret=i;
}
else
{
X509err(X509_F_X509_LOAD_CRL_FILE,X509_R_BAD_X509_FILETYPE);
goto err;
}
err:
if (x != NULL) X509_CRL_free(x);
if (in != NULL) BIO_free(in);
return(ret);
}
int X509_load_cert_crl_buf(X509_LOOKUP *ctx, const char *certBuf, int type)
{
STACK_OF(X509_INFO) *inf;
X509_INFO *itmp;
BIO *in;
int i, count = 0;
if(type != X509_FILETYPE_PEM)
return X509_load_cert_buf(ctx, certBuf, type);
in = BIO_new(BIO_s_mem());
if(!in) {
X509err(X509_F_X509_LOAD_CERT_CRL_FILE,ERR_R_SYS_LIB);
return 0;
}
BIO_write(in, certBuf, strlen(certBuf));
inf = PEM_X509_INFO_read_bio(in, NULL, NULL, NULL);
BIO_free(in);
if(!inf) {
X509err(X509_F_X509_LOAD_CERT_CRL_FILE,ERR_R_PEM_LIB);
return 0;
}
for(i = 0; i < sk_X509_INFO_num(inf); i++) {
itmp = sk_X509_INFO_value(inf, i);
if(itmp->x509) {
X509_STORE_add_cert(ctx->store_ctx, itmp->x509);
count++;
}
if(itmp->crl) {
X509_STORE_add_crl(ctx->store_ctx, itmp->crl);
count++;
}
}
sk_X509_INFO_pop_free(inf, X509_INFO_free);
return count;
}
C ++中的例程调用上述例程：
#include "by_buffer.h"
static int check(X509_STORE *ctx, const char *certBuf);
static X509 *load_cert(const char *certBuf);
int validateKey(const char *rsaKeyCA, const char *rsaCertificate) {
int ret=0;
X509_STORE *cert_ctx=NULL;
X509_LOOKUP *lookup=NULL;
cert_ctx=X509_STORE_new();
if (cert_ctx == NULL) goto end;
OpenSSL_add_all_algorithms();
lookup=X509_STORE_add_lookup(cert_ctx,X509_LOOKUP_buffer());
if (lookup == NULL)
goto end;
if(!X509_LOOKUP_load_buf(lookup,rsaKeyCA,X509_FILETYPE_PEM))
goto end;
lookup=X509_STORE_add_lookup(cert_ctx,X509_LOOKUP_hash_dir());
if (lookup == NULL)
goto end;
X509_LOOKUP_add_dir(lookup,NULL,X509_FILETYPE_DEFAULT);
ret = check(cert_ctx, rsaCertificate);
end:
if (cert_ctx != NULL) X509_STORE_free(cert_ctx);
return ret;
}
static X509 *load_cert(const char *certBuf)
{
X509 *x=NULL;
BIO *cert;
if ((cert=BIO_new(BIO_s_mem())) == NULL)
goto end;
BIO_write(cert, certBuf, strlen(certBuf));
x=PEM_read_bio_X509_AUX(cert,NULL, NULL, NULL);
end:
if (cert != NULL) BIO_free(cert);
return(x);
}
static int check(X509_STORE *ctx, const char *certBuf)
{
X509 *x=NULL;
int i=0,ret=0;
X509_STORE_CTX *csc;
x = load_cert(certBuf);
if (x == NULL)
goto end;
csc = X509_STORE_CTX_new();
if (csc == NULL)
goto end;
X509_STORE_set_flags(ctx, 0);
if(!X509_STORE_CTX_init(csc,ctx,x,0))
goto end;
////// See crypto/asn1/t_x509.c for ideas on how to access and print the values
//printf("X.509 name: %s\n", x->name);
i=X509_verify_cert(csc);
X509_STORE_CTX_free(csc);
ret=0;
end:
ret = (i > 0);
if (x != NULL)
X509_free(x);
return(ret);
}
答案 1 :(得分：4)
我自己遇到了这个问题，并开始使用非常接近OP的代码。我的证书链包括3个证书： 证书1（root-ca）发行人：root-ca主题：root-ca 证书2（签署ca）发行人：root-ca主题：签署ca. 证书3（设备）发行人：签署ca主题：设备
我想验证设备证书。我的ca.pem等价物（wrt OP）包含root-ca和signing-ca。
X509_verify_cert函数需要整个证书链一直到X509_store中的根（root-ca＆amp; signing-ca）。
以下是我的代码。省略了对返回值的检查以缩小代码。
int getIssuerCert(X509_STORE *x509_store){
STACK_OF(X509_INFO) *inf;
X509_INFO *itmp;
BIO *in;
int i, count = 0;
in = BIO_new(BIO_s_mem());
BIO_write(in, issuerCertStr, strlen(issuerCertStr)); //string containing root-ca & signing-ca
inf = PEM_X509_INFO_read_bio(in, NULL, NULL, NULL);
if(in != NULL) BIO_free(in);
for(i = 0; i < sk_X509_INFO_num(inf); i++) {
itmp = sk_X509_INFO_value(inf, i);
if(itmp->x509) {
X509_STORE_add_cert(x509_store, itmp->x509);
count++;
}
if(itmp->crl) {
X509_STORE_add_crl(x509_store, itmp->crl);
count++;
}
}
sk_X509_INFO_pop_free(inf, X509_INFO_free);
return 0;
}
int verify_cert(){
int ret = 0;
X509 *devCert = NULL;
X509_STORE *x509_store = NULL;
X509_STORE_CTX *x509_store_ctx = NULL;
OpenSSL_add_all_algorithms();
devCert = getDeviceCert(); // Returns X509 pointer
x509_store = X509_STORE_new();
X509_STORE_set_verify_cb(x509_store, verify_cb);
X509_STORE_set_flags(x509_store, 0);
x509_store_ctx = X509_STORE_CTX_new();
X509_STORE_CTX_init(x509_store_ctx, x509_store, devCert, NULL)
X509_STORE_CTX_set_purpose(x509_store_ctx, X509_PURPOSE_ANY);
ret = X509_verify_cert(x509_store_ctx);
if(x509_store_ctx != NULL) X509_STORE_CTX_free(x509_store_ctx);
if(x509_store != NULL) X509_STORE_free(x509_store);
if(devCert != NULL) X509_free(devCert);
EVP_cleanup();
return ret;
}
我不需要创建任何查找方法。对我来说，关键是从内存中的字符串循环我的证书，所以我拥有完成链所需的所有证书。该字符串相当于我将用于选项-CAfile的openssl验证。
此外，请确保使用时X509指针不为空。
答案 2 :(得分：3)
可能的答案（没有代表点添加评论，抱歉）：SSL_CTX_load_verify_locations(3)的联机帮助页说明了
When building its own certificate chain, an OpenSSL client/server will try to fill in
missing certificates from CAfile/CApath, if the certificate chain was not explicitly
specified (see SSL_CTX_add_extra_chain_cert(3), SSL_CTX_use_certificate(3).
（没有匹配他们的，不是我的。）
这似乎意味着，作为SSL_CTX_load_verify_locations(3)的替代方案，应该可以使用SSL_CTX_add_extra_chain_cert(3)或SSL_CTX_use_certificate(3) - 两者都采用X509 * arg。因此，不再需要Ed先生的解决方案，如上所述。
答案 3 :(得分：2)
请查看SSL_CTX_load_verify_locations ()功能：http://www.openssl.org/docs/ssl/SSL_CTX_load_verify_locations.html
SSL_CTX_load_verify_locations（）指定ctx的位置，at 用于验证目的的CA证书。该 通过CAfile和CApath提供的证书是可信的。
您可以生成包含ca.pem server.pem：
的CA证书文件 #!/bin/sh
rm CAfile.pem
for i in ca.pem server.pem ; do
openssl x509 -in $i -text >> CAfile.pem
done
然后将CAfile变量设置为指向CAfile.pem文件。
希望它有所帮助！
答案 4 :(得分：2)
我想，您可以使用＆＃34; X509_STORE_set_verify_cb＆＃34;添加回调以识别实际错误：
static int verify_cb(int ok, X509_STORE_CTX *ctx)
{
if (!ok)
{
/* check the error code and current cert*/
X509 *currentCert = X509_STORE_CTX_get_current_cert(ctx);
int certError = X509_STORE_CTX_get_error(ctx);
int depth = X509_STORE_CTX_get_error_depth(ctx);
printCert(currentCert);
printf("Error depth %d, certError %d", depth, certError)
}
return(ok);
}
int verify_cert(X509 *cert, X509 *cacert)
{
int ret;
X509_STORE *store;
X509_STORE_CTX *ctx;
store = X509_STORE_new();
X509_STORE_set_verify_cb(store, verify_cb);
X590_STORE_add_cert(store, cacert);
ctx = X509_STORE_CTX_new();
X509_STORE_CTX_init(ctx, store, cert, NULL);
ret = X590_verify_cert(ctx);
/* check for errors and clean up */
}
除非我们知道错误代码，否则很难猜出实际问题。否则代码看起来没问题。
答案 5 :(得分：0)
请参阅官方源代码： apps / verify.c
static int check(X509_STORE *ctx, const char *file,
STACK_OF(X509) *uchain, STACK_OF(X509) *tchain,
STACK_OF(X509_CRL) *crls, int show_chain);
您可以在此处查看如何输出“确定”：
if (i > 0 && X509_STORE_CTX_get_error(csc) == X509_V_OK) {
printf("%s: OK\n", (file == NULL) ? "stdin" : file);
功能依赖性可以在apps / apps.c中找到