[xmlsec] Verifying a signature against a PEM certificate, SOLUTION!

[Asbj�rn Oskal]

Hi! I seem to have found a solution to my problem.   I wanted to use a X509 pem certificate to validate a signature but I did not find a straightforward solution to load a public key from a certificate. I have struggled a bit to work this out but it turned out wasn't so bad afterall. Since I could not load a PEM certificate directly I have to get the (in my case) RSA public key from the certificate and turn it into a xmlSecKeyPtr.   Here is my function which does that and returns an xmlSecKeyPtr:     static xmlSecKeyPtr ReadPublicKeyFromPemCert(const char* certFile){  xmlSecKeyPtr retval = NULL;    // Load certificate from file  FILE* fid = fopen(certFile, "r");  X509* pCert = PEM_read_X509(fid, NULL, NULL, NULL);  fclose(fid);    // Get the public key from the certificate  EVP_PKEY *pPublicKey = X509_get_pubkey(pCert);    if(!pPublicKey){   printf("Failed to get public key from cert\n");     return NULL;  }    // I only handle RSA keys  if(pPublicKey->type == EVP_PKEY_RSA){   retval = xmlSecKeyCreate(xmlSecRsaKey, xmlSecKeyOriginX509);   if(xmlSecRsaKeyGenerate(retval, pPublicKey->pkey.rsa) < 0){    printf("Failed to generate public key from RSA key\n");    xmlSecKeyDestroy(retval);    EVP_PKEY_free(pPublicKey);          return NULL;   }   EVP_PKEY_free(pPublicKey);     return retval;  }    EVP_PKEY_free(pPublicKey);    printf("Unknown public key type in cert");    return NULL; }     I then use this public key together with xmlSecDSigValidate and it seems to work Ok.   Please comment if you see something bad about this.   Thanks for all help!