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mbedtls | 01 - 移植mbedtls库到STM32的两种方法
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mbedtls | 02 - 伪随机数生成器（ctr_drbg）的配置与使用
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mbedtls | 03 - 单向散列算法的配置与使用（MD5、SHA1、SHA256、SHA512）
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mbedtls | 04 - 对称加密算法的配置与使用（AES算法）
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mbedtls | 05 - 消息认证码的配置与使用（HMAC算法、GCM算法）
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mbedtls | 06 - 非对称加密算法的配置与使用（RSA算法）
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mbedtls | 07 - DH秘钥协商算法的配置与使用
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mbedtls | 08 - ECDH秘钥协商算法的配置与使用
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mbedtls | 09 - 数字签名算法的配置与使用（RSA数字签名算法、ECDSA数字签名算法）
Demo工程源码
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https://github.com/Mculover666/mbedtls-study-demo
本工程基于STM32L41RCT6开发板，包含了本系列文章中所编写的所有Demo，持续更新……
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mbedtls系列文章
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Demo工程源码
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一、X.509证书标准
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1. X.509证书的结构
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2. 获取证书示例（百度）
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3. 查看百度证书内容
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二、X509证书解析验证功能的配置与使用
openssl x509 -text -in baidu_3.cer -noout
① 证书颁发者和使用者信息：
② 公钥算法和公钥内容：
③ 签名算法和内容：
同样的方法可以查看百度二级证书和百度一级证书（根证书）的内容。
二、X509证书解析验证功能的配置与使用
1. 配置宏
* \def MBEDTLS_PK_C
* Enable the generic public (asymetric) key layer.
* Module: library/pk.c
* Caller: library/ssl_tls.c
* library/ssl_cli.c
* library/ssl_srv.c
* Requires: MBEDTLS_RSA_C or MBEDTLS_ECP_C
* Uncomment to enable generic public key wrappers.
#define MBEDTLS_PK_C
* \def MBEDTLS_PK_PARSE_C
* Enable the generic public (asymetric) key parser.
* Module: library/pkparse.c
* Caller: library/x509_crt.c
* library/x509_csr.c
* Requires: MBEDTLS_PK_C
* Uncomment to enable generic public key parse functions.
#define MBEDTLS_PK_PARSE_C
* \def MBEDTLS_ASN1_PARSE_C
* Enable the generic ASN1 parser.
* Module: library/asn1.c
* Caller: library/x509.c
* library/dhm.c
* library/pkcs12.c
* library/pkcs5.c
* library/pkparse.c
#define MBEDTLS_ASN1_PARSE_C
* \def MBEDTLS_ASN1_WRITE_C
* Enable the generic ASN1 writer.
* Module: library/asn1write.c
* Caller: library/ecdsa.c
* library/pkwrite.c
* library/x509_create.c
* library/x509write_crt.c
* library/x509write_csr.c
#define MBEDTLS_ASN1_WRITE_C
* \def MBEDTLS_X509_USE_C
* Enable X.509 core for using certificates.
* Module: library/x509.c
* Caller: library/x509_crl.c
* library/x509_crt.c
* library/x509_csr.c
* Requires: MBEDTLS_ASN1_PARSE_C, MBEDTLS_BIGNUM_C, MBEDTLS_OID_C,
* MBEDTLS_PK_PARSE_C
* This module is required for the X.509 parsing modules.
#define MBEDTLS_X509_USE_C
* \def MBEDTLS_BASE64_C
* Enable the Base64 module.
* Module: library/base64.c
* Caller: library/pem.c
* This module is required for PEM support (required by X.509).
#define MBEDTLS_BASE64_C
* \def MBEDTLS_PEM_PARSE_C
* Enable PEM decoding / parsing.
* Module: library/pem.c
* Caller: library/dhm.c
* library/pkparse.c
* library/x509_crl.c
* library/x509_crt.c
* library/x509_csr.c
* Requires: MBEDTLS_BASE64_C
* This modules adds support for decoding / parsing PEM files.
#define MBEDTLS_PEM_PARSE_C
* \def MBEDTLS_X509_CRT_PARSE_C
* Enable X.509 certificate parsing.
* Module: library/x509_crt.c
* Caller: library/ssl_cli.c
* library/ssl_srv.c
* library/ssl_tls.c
* Requires: MBEDTLS_X509_USE_C
* This module is required for X.509 certificate parsing.
#define MBEDTLS_X509_CRT_PARSE_C
新建配置文件mbedtls_config_x509.h，编辑以下内容：
* @brief Minimal configuration for X509 Function
* @author mculover666
* @date 2020/10/04
#ifndef _MBEDTLS_CONFIG_X509_H_
#define _MBEDTLS_CONFIG_X509_H_
/* System support */
#define MBEDTLS_HAVE_ASM
//#define MBEDTLS_HAVE_TIME
/* mbed feature support */
#define MBEDTLS_ENTROPY_HARDWARE_ALT
//#define MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES
#define MBEDTLS_NO_PLATFORM_ENTROPY
/* mbed modules */
#define MBEDTLS_SHA1_C
#define MBEDTLS_SHA256_C
#define MBEDTLS_MD_C
#define MBEDTLS_BIGNUM_C
#define MBEDTLS_OID_C
#define MBEDTLS_RSA_C
#define MBEDTLS_PKCS1_V21
#define MBEDTLS_PK_C
#define MBEDTLS_PK_PARSE_C
#define MBEDTLS_ASN1_PARSE_C
#define MBEDTLS_ASN1_WRITE_C
#define MBEDTLS_X509_USE_C
#define MBEDTLS_BASE64_C
#define MBEDTLS_PEM_PARSE_C
#define MBEDTLS_X509_CRT_PARSE_C
#include "mbedtls/check_config.h"
#endif /* _MBEDTLS_CONFIG_X509_H_ */
在MDK中配置使用该文件：
2. API说明
使用时需要包含头文件：
#include "mbedtls/x509_crt.h"
① 初始化证书结构体
* \brief Initialize a certificate (chain)
* \param crt Certificate chain to initialize
void mbedtls_x509_crt_init( mbedtls_x509_crt *crt );
② 证书解析
* \brief Parse one DER-encoded or one or more concatenated PEM-encoded
* certificates and add them to the chained list.
* For CRTs in PEM encoding, the function parses permissively:
* if at least one certificate can be parsed, the function
* returns the number of certificates for which parsing failed
* (hence \c 0 if all certificates were parsed successfully).
* If no certificate could be parsed, the function returns
* the first (negative) error encountered during parsing.
* PEM encoded certificates may be interleaved by other data
* such as human readable descriptions of their content, as
* long as the certificates are enclosed in the PEM specific
* '-----{BEGIN/END} CERTIFICATE-----' delimiters.
* \param chain The chain to which to add the parsed certificates.
* \param buf The buffer holding the certificate data in PEM or DER format.
* For certificates in PEM encoding, this may be a concatenation
* of multiple certificates; for DER encoding, the buffer must
* comprise exactly one certificate.
* \param buflen The size of \p buf, including the terminating \c NULL byte
* in case of PEM encoded data.
* \return \c 0 if all certificates were parsed successfully.
* \return The (positive) number of certificates that couldn't
* be parsed if parsing was partly successful (see above).
* \return A negative X509 or PEM error code otherwise.
int mbedtls_x509_crt_parse( mbedtls_x509_crt *chain, const unsigned char *buf, size_t buflen );
③ 获取证书信息
* \brief Returns an informational string about the
* certificate.
* \param buf Buffer to write to
* \param size Maximum size of buffer
* \param prefix A line prefix
* \param crt The X509 certificate to represent
* \return The length of the string written (not including the
* terminated nul byte), or a negative error code.
int mbedtls_x509_crt_info( char *buf, size_t size, const char *prefix,
const mbedtls_x509_crt *crt );
④ 获取证书认证信息：
* \brief Returns an informational string about the
* verification status of a certificate.
* \param buf Buffer to write to
* \param size Maximum size of buffer
* \param prefix A line prefix
* \param flags Verification flags created by mbedtls_x509_crt_verify()
* \return The length of the string written (not including the
* terminated nul byte), or a negative error code.
int mbedtls_x509_crt_verify_info( char *buf, size_t size, const char *prefix,
uint32_t flags );
⑤ 证书认证
* \brief Verify a chain of certificates.
* The verify callback is a user-supplied callback that
* can clear / modify / add flags for a certificate. If set,
* the verification callback is called for each
* certificate in the chain (from the trust-ca down to the
* presented crt). The parameters for the callback are:
* (void *parameter, mbedtls_x509_crt *crt, int certificate_depth,
* int *flags). With the flags representing current flags for
* that specific certificate and the certificate depth from
* the bottom (Peer cert depth = 0).
* All flags left after returning from the callback
* are also returned to the application. The function should
* return 0 for anything (including invalid certificates)
* other than fatal error, as a non-zero return code
* immediately aborts the verification process. For fatal
* errors, a specific error code should be used (different
* from MBEDTLS_ERR_X509_CERT_VERIFY_FAILED which should not
* be returned at this point), or MBEDTLS_ERR_X509_FATAL_ERROR
* can be used if no better code is available.
* \note In case verification failed, the results can be displayed
* using \c mbedtls_x509_crt_verify_info()
* \note Same as \c mbedtls_x509_crt_verify_with_profile() with the
* default security profile.
* \note It is your responsibility to provide up-to-date CRLs for
* all trusted CAs. If no CRL is provided for the CA that was
* used to sign the certificate, CRL verification is skipped
* silently, that is *without* setting any flag.
* \note The \c trust_ca list can contain two types of certificates:
* (1) those of trusted root CAs, so that certificates
* chaining up to those CAs will be trusted, and (2)
* self-signed end-entity certificates to be trusted (for
* specific peers you know) - in that case, the self-signed
* certificate doesn't need to have the CA bit set.
* \param crt The certificate chain to be verified.
* \param trust_ca The list of trusted CAs.
* \param ca_crl The list of CRLs for trusted CAs.
* \param cn The expected Common Name. This will be checked to be
* present in the certificate's subjectAltNames extension or,
* if this extension is absent, as a CN component in its
* Subject name. Currently only DNS names are supported. This
* may be \c NULL if the CN need not be verified.
* \param flags The address at which to store the result of the verification.
* If the verification couldn't be completed, the flag value is
* set to (uint32_t) -1.
* \param f_vrfy The verification callback to use. See the documentation
* of mbedtls_x509_crt_verify() for more information.
* \param p_vrfy The context to be passed to \p f_vrfy.
* \return \c 0 if the chain is valid with respect to the
* passed CN, CAs, CRLs and security profile.
* \return #MBEDTLS_ERR_X509_CERT_VERIFY_FAILED in case the
* certificate chain verification failed. In this case,
* \c *flags will have one or more
* \c MBEDTLS_X509_BADCERT_XXX or \c MBEDTLS_X509_BADCRL_XXX
* flags set.
* \return Another negative error code in case of a fatal error
* encountered during the verification process.
int mbedtls_x509_crt_verify( mbedtls_x509_crt *crt,
mbedtls_x509_crt *trust_ca,
mbedtls_x509_crl *ca_crl,
const char *cn, uint32_t *flags,
int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
void *p_vrfy );
⑥ 释放证书结构体
* \brief Unallocate all certificate data
* \param crt Certificate chain to free
void mbedtls_x509_crt_free( mbedtls_x509_crt *crt );
⑦ 错误码：
* \name X509 Error codes
#define MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE -0x2080 /**< Unavailable feature, e.g. RSA hashing/encryption combination. */
#define MBEDTLS_ERR_X509_UNKNOWN_OID -0x2100 /**< Requested OID is unknown. */
#define MBEDTLS_ERR_X509_INVALID_FORMAT -0x2180 /**< The CRT/CRL/CSR format is invalid, e.g. different type expected. */
#define MBEDTLS_ERR_X509_INVALID_VERSION -0x2200 /**< The CRT/CRL/CSR version element is invalid. */
#define MBEDTLS_ERR_X509_INVALID_SERIAL -0x2280 /**< The serial tag or value is invalid. */
#define MBEDTLS_ERR_X509_INVALID_ALG -0x2300 /**< The algorithm tag or value is invalid. */
#define MBEDTLS_ERR_X509_INVALID_NAME -0x2380 /**< The name tag or value is invalid. */
#define MBEDTLS_ERR_X509_INVALID_DATE -0x2400 /**< The date tag or value is invalid. */
#define MBEDTLS_ERR_X509_INVALID_SIGNATURE -0x2480 /**< The signature tag or value invalid. */
#define MBEDTLS_ERR_X509_INVALID_EXTENSIONS -0x2500 /**< The extension tag or value is invalid. */
#define MBEDTLS_ERR_X509_UNKNOWN_VERSION -0x2580 /**< CRT/CRL/CSR has an unsupported version number. */
#define MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG -0x2600 /**< Signature algorithm (oid) is unsupported. */
#define MBEDTLS_ERR_X509_SIG_MISMATCH -0x2680 /**< Signature algorithms do not match. (see \c ::mbedtls_x509_crt sig_oid) */
#define MBEDTLS_ERR_X509_CERT_VERIFY_FAILED -0x2700 /**< Certificate verification failed, e.g. CRL, CA or signature check failed. */
#define MBEDTLS_ERR_X509_CERT_UNKNOWN_FORMAT -0x2780 /**< Format not recognized as DER or PEM. */
#define MBEDTLS_ERR_X509_BAD_INPUT_DATA -0x2800 /**< Input invalid. */
#define MBEDTLS_ERR_X509_ALLOC_FAILED -0x2880 /**< Allocation of memory failed. */
#define MBEDTLS_ERR_X509_FILE_IO_ERROR -0x2900 /**< Read/write of file failed. */
#define MBEDTLS_ERR_X509_BUFFER_TOO_SMALL -0x2980 /**< Destination buffer is too small. */
#define MBEDTLS_ERR_X509_FATAL_ERROR -0x3000 /**< A fatal error occurred, eg the chain is too long or the vrfy callback failed. */
3. 编写测试函数
编写头文件baidu_certs.h，将百度的证书存储：
#ifndef __CERTS_H__
#define __CERTS_H__
const char baidu_ca_cert[] =
"-----BEGIN CERTIFICATE-----\r\n"
"MIIKLjCCCRagAwIBAgIMclh4Nm6fVugdQYhIMA0GCSqGSIb3DQEBCwUAMGYxCzAJ\r\n"
"BgNVBAYTAkJFMRkwFwYDVQQKExBHbG9iYWxTaWduIG52LXNhMTwwOgYDVQQDEzNH\r\n"
"bG9iYWxTaWduIE9yZ2FuaXphdGlvbiBWYWxpZGF0aW9uIENBIC0gU0hBMjU2IC0g\r\n"
"RzIwHhcNMjAwNDAyMDcwNDU4WhcNMjEwNzI2MDUzMTAyWjCBpzELMAkGA1UEBhMC\r\n"
"Q04xEDAOBgNVBAgTB2JlaWppbmcxEDAOBgNVBAcTB2JlaWppbmcxJTAjBgNVBAsT\r\n"
"HHNlcnZpY2Ugb3BlcmF0aW9uIGRlcGFydG1lbnQxOTA3BgNVBAoTMEJlaWppbmcg\r\n"
"QmFpZHUgTmV0Y29tIFNjaWVuY2UgVGVjaG5vbG9neSBDby4sIEx0ZDESMBAGA1UE\r\n"
"AxMJYmFpZHUuY29tMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAwamw\r\n"
"rkca0lfrHRUfblyy5PgLINvqAN8p/6RriSZLnyMv7FewirhGQCp+vNxaRZdPrUEO\r\n"
"vCCGSwxdVSFH4jE8V6fsmUfrRw1y18gWVHXv00URD0vOYHpGXCh0ro4bvthwZnuo\r\n"
"k0ko0qN2lFXefCfyD/eYDK2G2sau/Z/w2YEympfjIe4EkpbkeBHlxBAOEDF6Speg\r\n"
"68ebxNqJN6nDN9dWsX9Sx9kmCtavOBaxbftzebFoeQOQ64h7jEiRmFGlB5SGpXhG\r\n"
"eY9Ym+k1Wafxe1cxCpDPJM4NJOeSsmrp5pY3Crh8hy900lzoSwpfZhinQYbPJqYI\r\n"
"jqVJF5JTs5Glz1OwMQIDAQABo4IGmDCCBpQwDgYDVR0PAQH/BAQDAgWgMIGgBggr\r\n"
"BgEFBQcBAQSBkzCBkDBNBggrBgEFBQcwAoZBaHR0cDovL3NlY3VyZS5nbG9iYWxz\r\n"
"aWduLmNvbS9jYWNlcnQvZ3Nvcmdhbml6YXRpb252YWxzaGEyZzJyMS5jcnQwPwYI\r\n"
"KwYBBQUHMAGGM2h0dHA6Ly9vY3NwMi5nbG9iYWxzaWduLmNvbS9nc29yZ2FuaXph\r\n"
"dGlvbnZhbHNoYTJnMjBWBgNVHSAETzBNMEEGCSsGAQQBoDIBFDA0MDIGCCsGAQUF\r\n"
"BwIBFiZodHRwczovL3d3dy5nbG9iYWxzaWduLmNvbS9yZXBvc2l0b3J5LzAIBgZn\r\n"
"gQwBAgIwCQYDVR0TBAIwADBJBgNVHR8EQjBAMD6gPKA6hjhodHRwOi8vY3JsLmds\r\n"
"b2JhbHNpZ24uY29tL2dzL2dzb3JnYW5pemF0aW9udmFsc2hhMmcyLmNybDCCA04G\r\n"
"A1UdEQSCA0UwggNBggliYWlkdS5jb22CDGJhaWZ1YmFvLmNvbYIMd3d3LmJhaWR1\r\n"
"LmNughB3d3cuYmFpZHUuY29tLmNugg9tY3QueS5udW9taS5jb22CC2Fwb2xsby5h\r\n"
"dXRvggZkd3ouY26CCyouYmFpZHUuY29tgg4qLmJhaWZ1YmFvLmNvbYIRKi5iYWlk\r\n"
"dXN0YXRpYy5jb22CDiouYmRzdGF0aWMuY29tggsqLmJkaW1nLmNvbYIMKi5oYW8x\r\n"
"MjMuY29tggsqLm51b21pLmNvbYINKi5jaHVhbmtlLmNvbYINKi50cnVzdGdvLmNv\r\n"
"bYIPKi5iY2UuYmFpZHUuY29tghAqLmV5dW4uYmFpZHUuY29tgg8qLm1hcC5iYWlk\r\n"
"dS5jb22CDyoubWJkLmJhaWR1LmNvbYIRKi5mYW55aS5iYWlkdS5jb22CDiouYmFp\r\n"
"ZHViY2UuY29tggwqLm1pcGNkbi5jb22CECoubmV3cy5iYWlkdS5jb22CDiouYmFp\r\n"
"ZHVwY3MuY29tggwqLmFpcGFnZS5jb22CCyouYWlwYWdlLmNugg0qLmJjZWhvc3Qu\r\n"
"Y29tghAqLnNhZmUuYmFpZHUuY29tgg4qLmltLmJhaWR1LmNvbYISKi5iYWlkdWNv\r\n"
"bnRlbnQuY29tggsqLmRsbmVsLmNvbYILKi5kbG5lbC5vcmeCEiouZHVlcm9zLmJh\r\n"
"aWR1LmNvbYIOKi5zdS5iYWlkdS5jb22CCCouOTEuY29tghIqLmhhbzEyMy5iYWlk\r\n"
"dS5jb22CDSouYXBvbGxvLmF1dG+CEioueHVlc2h1LmJhaWR1LmNvbYIRKi5iai5i\r\n"
"YWlkdWJjZS5jb22CESouZ3ouYmFpZHViY2UuY29tgg4qLnNtYXJ0YXBwcy5jboIN\r\n"
"Ki5iZHRqcmN2LmNvbYIMKi5oYW8yMjIuY29tggwqLmhhb2thbi5jb22CDyoucGFl\r\n"
"LmJhaWR1LmNvbYIRKi52ZC5iZHN0YXRpYy5jb22CEmNsaWNrLmhtLmJhaWR1LmNv\r\n"
"bYIQbG9nLmhtLmJhaWR1LmNvbYIQY20ucG9zLmJhaWR1LmNvbYIQd24ucG9zLmJh\r\n"
"aWR1LmNvbYIUdXBkYXRlLnBhbi5iYWlkdS5jb20wHQYDVR0lBBYwFAYIKwYBBQUH\r\n"
"AwEGCCsGAQUFBwMCMB8GA1UdIwQYMBaAFJbeYfG9HBYpUxzAzH07gwBA5hp8MB0G\r\n"
"A1UdDgQWBBSeyXnX6VurihbMMo7GmeafIEI1hzCCAX4GCisGAQQB1nkCBAIEggFu\r\n"
"BIIBagFoAHYAXNxDkv7mq0VEsV6a1FbmEDf71fpH3KFzlLJe5vbHDsoAAAFxObU8\r\n"
"ugAABAMARzBFAiBphmgxIbNZXaPWiUqXRWYLaRST38KecoekKIof5fXmsgIhAMkZ\r\n"
"tF8XyKCu/nZll1e9vIlKbW8RrUr/74HpmScVRRsBAHYAb1N2rDHwMRnYmQCkURX/\r\n"
"dxUcEdkCwQApBo2yCJo32RMAAAFxObU85AAABAMARzBFAiBURWwwTgXZ+9IV3mhm\r\n"
"E0EOzbg901DLRszbLIpafDY/XgIhALsvEGqbBVrpGxhKoTVlz7+GWom8SrfUeHcn\r\n"
"4+9Dn7xGAHYA9lyUL9F3MCIUVBgIMJRWjuNNExkzv98MLyALzE7xZOMAAAFxObU8\r\n"
"qwAABAMARzBFAiBFBYPxKEdhlf6bqbwxQY7tskgdoFulPxPmdrzS5tNpPwIhAKnK\r\n"
"qwzch98lINQYzLAV52+C8GXZPXFZNfhfpM4tQ6xbMA0GCSqGSIb3DQEBCwUAA4IB\r\n"
"AQC83ALQ2d6MxeLZ/k3vutEiizRCWYSSMYLVCrxANdsGshNuyM8B8V/A57c0Nzqo\r\n"
"CPKfMtX5IICfv9P/bUecdtHL8cfx24MzN+U/GKcA4r3a/k8pRVeHeF9ThQ2zo1xj\r\n"
"k/7gJl75koztdqNfOeYiBTbFMnPQzVGqyMMfqKxbJrfZlGAIgYHT9bd6T985IVgz\r\n"
"tRVjAoy4IurZenTsWkG7PafJ4kAh6jQaSu1zYEbHljuZ5PXlkhPO9DwW1WIPug6Z\r\n"
"rlylLTTYmlW3WETOATi70HYsZN6NACuZ4t1hEO3AsF7lqjdA2HwTN10FX2HuaUvf\r\n"
"5OzP+PKupV9VKw8x8mQKU6vr\r\n"
"-----END CERTIFICATE-----\r\n";
#endif
编写测试函数文件mbedtls_x509_test.c：
* @brief X509 Function demo
* @author mculover666
* @date 2020/10/04
#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#if defined(MBEDTLS_X509_CRT_PARSE_C)
#include <stdio.h>
#include "string.h"
#include "mbedtls/x509_crt.h"
#include "baidu_certs.h"
char buf[4096];
int mbedtls_x509_test(void)
int ret;
mbedtls_x509_crt cert, cacert;
/* 1. init structure */
mbedtls_x509_crt_init(&cert);
mbedtls_x509_crt_init(&cacert);
/* 2. Parser cacert */
printf( "\n . Parse cacert..." );
ret = mbedtls_x509_crt_parse(&cacert, (unsigned char *)baidu_ca_cert, sizeof(baidu_ca_cert));
if(ret != 0) {
printf( " failed\n ! mbedtls_x509_crt_parse cacert returned %d(-0x%04x)\n", ret, -ret);
goto exit;
printf( " ok\n" );
/* 2. Cacert parser result */
printf( "\n . Cacert parser result..." );
ret = mbedtls_x509_crt_info(buf, sizeof(buf) - 1, " ", &cacert);
if (ret < 0) {
printf("fail! mbedtls_x509_crt_info return %d(-0x%04x)\n", ret, -ret);
goto exit;
} else {
buf[ret] = '\0';
printf("ok!\r\n");
printf("crt info has %d chars\r\n", strlen(buf));
printf("%s\r\n", buf);
exit:
/* 3. release structure */
mbedtls_x509_crt_free(&cert);
mbedtls_x509_crt_free(&cacert);
return ret;
#endif /* MBEDTLS_RSA_C */
4. 测试结果
在main.c中声明该测试函数：
extern int mbedtls_x509_test(void);
在main函数中调用该测试函数：
/* 10. x509 test */
mbedtls_x509_test();
编译、下载、测试结果为：
