c++ - 阅读和验证证书

Question

您好，我有两个证书，即 mycert.crt 和 root.crt。我需要验证我的证书是否由根证书签名。我正在使用以下代码使用以下代码来执行此操作，但出现错误段错误(核心已转储)

static int verifyCerti (BYTE *cert1, BYTE *cert2, int certlenght1, int certlenght2);

int main (int ac, char **av)
{
    FILE     *f_in, *f_in2;
    BYTE     *certBuf, *certBuf2;
    UINT32   certBufLen,certBufLen2;
    UINT32   certLen,certLen2;
    int      result;


    //////////// Reading first certificate/////

    certBufLen = 0;
    certBuf = malloc (1);
    //for (i=0; i<nCerts; i++) {
    if ((f_in = fopen (av[1], "rb")) == NULL) {
        fprintf (stderr, "Unable to open file %s for input\n", av[1]);
        exit (1);
    }
    fseek (f_in, 0, SEEK_END);
    certLen = ftell (f_in);
    fseek (f_in, 0, SEEK_SET);
    certBuf = realloc (certBuf, certBufLen + certLen);

    if (fread (certBuf+certBufLen, 1, certLen, f_in) != certLen) {
        fprintf (stderr, "Failed to read file %s\n", av[1]);
        exit (1);
    }
    if (certBuf[certBufLen] != 0x30) {
        fprintf (stderr, "Certificate file %s not in binary format\n", av[1]);
        exit (1);
    }
    fclose (f_in);
    printf ("we reach here %s \n", av[1]);


    ////////////////Reading second certificate/////////////////////////////////////////////////


    certBufLen2 = 0;
    certBuf2 = malloc (1);
    if ((f_in2 = fopen (av[2], "rb")) == NULL) {
        fprintf (stderr, "Unable to open file %s for input\n", av[2]);
        exit (1);
    }
    fseek (f_in2, 0, SEEK_END);
    certLen2 = ftell (f_in2);
    fseek (f_in2, 0, SEEK_SET);
    certBuf2 = realloc (certBuf2, certBufLen2 + certLen2);

    if (fread (certBuf2+certBufLen2, 1, certLen2, f_in2) != certLen2) {
        fprintf (stderr, "Failed to read file %s\n", av[2]);
        exit (1);
    }
    if (certBuf2[certBufLen2] != 0x30) {
        fprintf (stderr, "Certificate file %s not in binary format\n", av[2]);
        exit (1);
    }
    fclose (f_in2);

    printf ("we reach here %s \n", av[2]);

    if (verifyCerti (certBuf, certBuf2, certBufLen, certBufLen2) < 0) {
        fprintf (stderr, "Certificate chain is incorrect\n");
        exit (1);
    }
}

static int verifyCerti (BYTE *cert1, BYTE *cert2, int certLen1, int certLen2)
{

    X509 *root;
    X509 *mycert;

    root = d2i_X509 (NULL, (unsigned char const **)&cert2, certLen2);
    mycert = d2i_X509 (NULL, (unsigned char const **)&cert1, certLen1);

    //Get root certificate into root
    //Get mycert into mycert.

    //Get the public key.

    EVP_PKEY *pubkey = X509_get_pubkey(root);


    //verify. result less than or 0 means not verified or some error.

    int result = X509_verify(mycert, pubkey);

    //free the public key.

    EVP_PKEY_free(pubkey);

    return result;    
}

错误是我认为是因为 X509_verify()，但我不确定。

Answer 1

该函数的目的是验证 pkey(公钥)是否与用相应私钥签名的 serverCert 验证..

您实际上应该作为第二个参数传递的是公钥，其对应的私钥已经签署了参数 1 中传递的证书。我认为您没有传递正确的公钥。

尝试获取失败的错误代码。

unsigned int errCode = ERR_get_error();

printf("\nError: %s\n", ERR_error_string(errCode, NULL));
printf("\nLib: %s\n", ERR_lib_error_string(errCode));
printf("\nFunc: %s\n", ERR_func_error_string(errCode));
printf("\nReason: %s\n", ERR_reason_error_string(errCode));