examples/cacertinmem: ignore cert-already-exists error

- Ignore X509_R_CERT_ALREADY_IN_HASH_TABLE errors in the CTX callback
  since it's possible the cert may have already been loaded by libcurl.

- Remove the EXAMPLE code in the CURLOPT_SSL_CTX_FUNCTION.3 doc.
  Instead have it direct the reader to this cacertinmem.c example.

- Fix the CA certificate to use the right CA for example.com, Digicert.

Bug: https://curl.haxx.se/mail/lib-2017-12/0057.html
Reported-by: Thomas van Hesteren

Closes https://github.com/curl/curl/pull/2182
This commit is contained in:
Jay Satiro 2017-12-19 02:17:39 -05:00
parent 859ac36021
commit a0f3eaf25d
2 changed files with 92 additions and 125 deletions

View File

@ -24,85 +24,103 @@
* </DESC>
*/
#include <openssl/err.h>
#include <openssl/ssl.h>
#include <curl/curl.h>
#include <stdio.h>
size_t writefunction(void *ptr, size_t size, size_t nmemb, void *stream)
{
fwrite(ptr, size, nmemb, stream);
fwrite(ptr, size, nmemb, (FILE *)stream);
return (nmemb*size);
}
static CURLcode sslctx_function(CURL *curl, void *sslctx, void *parm)
{
X509_STORE *store;
CURLcode rv = CURLE_ABORTED_BY_CALLBACK;
X509_STORE *store = NULL;
X509 *cert = NULL;
BIO *bio;
char *mypem = /* www.cacert.org */
"-----BEGIN CERTIFICATE-----\n"\
"MIIHPTCCBSWgAwIBAgIBADANBgkqhkiG9w0BAQQFADB5MRAwDgYDVQQKEwdSb290\n"\
"IENBMR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNB\n"\
"IENlcnQgU2lnbmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRA\n"\
"Y2FjZXJ0Lm9yZzAeFw0wMzAzMzAxMjI5NDlaFw0zMzAzMjkxMjI5NDlaMHkxEDAO\n"\
"BgNVBAoTB1Jvb3QgQ0ExHjAcBgNVBAsTFWh0dHA6Ly93d3cuY2FjZXJ0Lm9yZzEi\n"\
"MCAGA1UEAxMZQ0EgQ2VydCBTaWduaW5nIEF1dGhvcml0eTEhMB8GCSqGSIb3DQEJ\n"\
"ARYSc3VwcG9ydEBjYWNlcnQub3JnMIICIjANBgkqhkiG9w0BAQEFAAOCAg8AMIIC\n"\
"CgKCAgEAziLA4kZ97DYoB1CW8qAzQIxL8TtmPzHlawI229Z89vGIj053NgVBlfkJ\n"\
"8BLPRoZzYLdufujAWGSuzbCtRRcMY/pnCujW0r8+55jE8Ez64AO7NV1sId6eINm6\n"\
"zWYyN3L69wj1x81YyY7nDl7qPv4coRQKFWyGhFtkZip6qUtTefWIonvuLwphK42y\n"\
"fk1WpRPs6tqSnqxEQR5YYGUFZvjARL3LlPdCfgv3ZWiYUQXw8wWRBB0bF4LsyFe7\n"\
"w2t6iPGwcswlWyCR7BYCEo8y6RcYSNDHBS4CMEK4JZwFaz+qOqfrU0j36NK2B5jc\n"\
"G8Y0f3/JHIJ6BVgrCFvzOKKrF11myZjXnhCLotLddJr3cQxyYN/Nb5gznZY0dj4k\n"\
"epKwDpUeb+agRThHqtdB7Uq3EvbXG4OKDy7YCbZZ16oE/9KTfWgu3YtLq1i6L43q\n"\
"laegw1SJpfvbi1EinbLDvhG+LJGGi5Z4rSDTii8aP8bQUWWHIbEZAWV/RRyH9XzQ\n"\
"QUxPKZgh/TMfdQwEUfoZd9vUFBzugcMd9Zi3aQaRIt0AUMyBMawSB3s42mhb5ivU\n"\
"fslfrejrckzzAeVLIL+aplfKkQABi6F1ITe1Yw1nPkZPcCBnzsXWWdsC4PDSy826\n"\
"YreQQejdIOQpvGQpQsgi3Hia/0PsmBsJUUtaWsJx8cTLc6nloQsCAwEAAaOCAc4w\n"\
"ggHKMB0GA1UdDgQWBBQWtTIb1Mfz4OaO873SsDrusjkY0TCBowYDVR0jBIGbMIGY\n"\
"gBQWtTIb1Mfz4OaO873SsDrusjkY0aF9pHsweTEQMA4GA1UEChMHUm9vdCBDQTEe\n"\
"MBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0\n"\
"IFNpZ25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2Vy\n"\
"dC5vcmeCAQAwDwYDVR0TAQH/BAUwAwEB/zAyBgNVHR8EKzApMCegJaAjhiFodHRw\n"\
"czovL3d3dy5jYWNlcnQub3JnL3Jldm9rZS5jcmwwMAYJYIZIAYb4QgEEBCMWIWh0\n"\
"dHBzOi8vd3d3LmNhY2VydC5vcmcvcmV2b2tlLmNybDA0BglghkgBhvhCAQgEJxYl\n"\
"aHR0cDovL3d3dy5jYWNlcnQub3JnL2luZGV4LnBocD9pZD0xMDBWBglghkgBhvhC\n"\
"AQ0ESRZHVG8gZ2V0IHlvdXIgb3duIGNlcnRpZmljYXRlIGZvciBGUkVFIGhlYWQg\n"\
"b3ZlciB0byBodHRwOi8vd3d3LmNhY2VydC5vcmcwDQYJKoZIhvcNAQEEBQADggIB\n"\
"ACjH7pyCArpcgBLKNQodgW+JapnM8mgPf6fhjViVPr3yBsOQWqy1YPaZQwGjiHCc\n"\
"nWKdpIevZ1gNMDY75q1I08t0AoZxPuIrA2jxNGJARjtT6ij0rPtmlVOKTV39O9lg\n"\
"18p5aTuxZZKmxoGCXJzN600BiqXfEVWqFcofN8CCmHBh22p8lqOOLlQ+TyGpkO/c\n"\
"gr/c6EWtTZBzCDyUZbAEmXZ/4rzCahWqlwQ3JNgelE5tDlG+1sSPypZt90Pf6DBl\n"\
"Jzt7u0NDY8RD97LsaMzhGY4i+5jhe1o+ATc7iwiwovOVThrLm82asduycPAtStvY\n"\
"sONvRUgzEv/+PDIqVPfE94rwiCPCR/5kenHA0R6mY7AHfqQv0wGP3J8rtsYIqQ+T\n"\
"SCX8Ev2fQtzzxD72V7DX3WnRBnc0CkvSyqD/HMaMyRa+xMwyN2hzXwj7UfdJUzYF\n"\
"CpUCTPJ5GhD22Dp1nPMd8aINcGeGG7MW9S/lpOt5hvk9C8JzC6WZrG/8Z7jlLwum\n"\
"GCSNe9FINSkYQKyTYOGWhlC0elnYjyELn8+CkcY7v2vcB5G5l1YjqrZslMZIBjzk\n"\
"zk6q5PYvCdxTby78dOs6Y5nCpqyJvKeyRKANihDjbPIky/qbn3BHLt4Ui9SyIAmW\n"\
"omTxJBzcoTWcFbLUvFUufQb1nA5V9FrWk9p2rSVzTMVD\n"\
BIO *bio = NULL;
char *mypem =
/* CA for example.com. CN = DigiCert High Assurance EV Root CA */
"-----BEGIN CERTIFICATE-----\n"
"MIIDxTCCAq2gAwIBAgIQAqxcJmoLQJuPC3nyrkYldzANBgkqhkiG9w0BAQUFADBs\n"
"MQswCQYDVQQGEwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMRkwFwYDVQQLExB3\n"
"d3cuZGlnaWNlcnQuY29tMSswKQYDVQQDEyJEaWdpQ2VydCBIaWdoIEFzc3VyYW5j\n"
"ZSBFViBSb290IENBMB4XDTA2MTExMDAwMDAwMFoXDTMxMTExMDAwMDAwMFowbDEL\n"
"MAkGA1UEBhMCVVMxFTATBgNVBAoTDERpZ2lDZXJ0IEluYzEZMBcGA1UECxMQd3d3\n"
"LmRpZ2ljZXJ0LmNvbTErMCkGA1UEAxMiRGlnaUNlcnQgSGlnaCBBc3N1cmFuY2Ug\n"
"RVYgUm9vdCBDQTCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAMbM5XPm\n"
"+9S75S0tMqbf5YE/yc0lSbZxKsPVlDRnogocsF9ppkCxxLeyj9CYpKlBWTrT3JTW\n"
"PNt0OKRKzE0lgvdKpVMSOO7zSW1xkX5jtqumX8OkhPhPYlG++MXs2ziS4wblCJEM\n"
"xChBVfvLWokVfnHoNb9Ncgk9vjo4UFt3MRuNs8ckRZqnrG0AFFoEt7oT61EKmEFB\n"
"Ik5lYYeBQVCmeVyJ3hlKV9Uu5l0cUyx+mM0aBhakaHPQNAQTXKFx01p8VdteZOE3\n"
"hzBWBOURtCmAEvF5OYiiAhF8J2a3iLd48soKqDirCmTCv2ZdlYTBoSUeh10aUAsg\n"
"EsxBu24LUTi4S8sCAwEAAaNjMGEwDgYDVR0PAQH/BAQDAgGGMA8GA1UdEwEB/wQF\n"
"MAMBAf8wHQYDVR0OBBYEFLE+w2kD+L9HAdSYJhoIAu9jZCvDMB8GA1UdIwQYMBaA\n"
"FLE+w2kD+L9HAdSYJhoIAu9jZCvDMA0GCSqGSIb3DQEBBQUAA4IBAQAcGgaX3Nec\n"
"nzyIZgYIVyHbIUf4KmeqvxgydkAQV8GK83rZEWWONfqe/EW1ntlMMUu4kehDLI6z\n"
"eM7b41N5cdblIZQB2lWHmiRk9opmzN6cN82oNLFpmyPInngiK3BD41VHMWEZ71jF\n"
"hS9OMPagMRYjyOfiZRYzy78aG6A9+MpeizGLYAiJLQwGXFK3xPkKmNEVX58Svnw2\n"
"Yzi9RKR/5CYrCsSXaQ3pjOLAEFe4yHYSkVXySGnYvCoCWw9E1CAx2/S6cCZdkGCe\n"
"vEsXCS+0yx5DaMkHJ8HSXPfqIbloEpw8nL+e/IBcm2PN7EeqJSdnoDfzAIJ9VNep\n"
"+OkuE6N36B9K\n"
"-----END CERTIFICATE-----\n";
/* clear the current thread's OpenSSL error queue */
ERR_clear_error();
/* get a BIO */
bio = BIO_new_mem_buf(mypem, -1);
if(!bio)
goto err;
/* use it to read the PEM formatted certificate from memory into an X509
* structure that SSL can use
*/
PEM_read_bio_X509(bio, &cert, 0, NULL);
if(cert == NULL)
printf("PEM_read_bio_X509 failed...\n");
if(!PEM_read_bio_X509(bio, &cert, 0, NULL))
goto err;
/* get a pointer to the X509 certificate store (which may be empty!) */
store = SSL_CTX_get_cert_store((SSL_CTX *)sslctx);
if(!store)
goto err;
/* add our certificate to this store */
if(X509_STORE_add_cert(store, cert) == 0)
printf("error adding certificate\n");
if(!X509_STORE_add_cert(store, cert)) {
unsigned long error = ERR_peek_last_error();
/* Ignore error X509_R_CERT_ALREADY_IN_HASH_TABLE which means the
* certificate is already in the store. That could happen if
* libcurl already loaded the certificate from a ca cert bundle
* set at libcurl build-time or runtime.
*/
if(ERR_GET_LIB(error) != ERR_LIB_X509 ||
ERR_GET_REASON(error) != X509_R_CERT_ALREADY_IN_HASH_TABLE)
goto err;
ERR_clear_error();
}
rv = CURLE_OK;
err:
if(rv != CURLE_OK) {
char errbuf[256];
unsigned long error = ERR_peek_last_error();
fprintf(stderr, "error adding certificate\n");
if(error) {
ERR_error_string_n(error, errbuf, sizeof errbuf);
fprintf(stderr, "%s\n", errbuf);
}
}
/* decrease reference counts */
X509_free(cert);
BIO_free(bio);
ERR_clear_error();
/* all set to go */
return CURLE_OK;
return rv;
}
int main(void)
@ -124,7 +142,15 @@ int main(void)
rv = curl_easy_setopt(ch, CURLOPT_SSL_VERIFYPEER, 1L);
rv = curl_easy_setopt(ch, CURLOPT_URL, "https://www.example.com/");
/* first try: retrieve page without cacerts' certificate -> will fail
/* turn off the default CA locations (optional)
* otherwise libcurl will load CA certificates from the locations that
* were detected/specified at build-time
*/
rv = curl_easy_setopt(ch, CURLOPT_CAINFO, NULL);
rv = curl_easy_setopt(ch, CURLOPT_CAPATH, NULL);
/* first try: retrieve page without ca certificates -> should fail
* unless libcurl was built --with-ca-fallback enabled at build-time
*/
rv = curl_easy_perform(ch);
if(rv == CURLE_OK)
@ -132,6 +158,17 @@ int main(void)
else
printf("*** transfer failed ***\n");
/* use a fresh connection (optional)
* this option seriously impacts performance of multiple transfers but
* it is necessary order to demonstrate this example. recall that the
* ssl ctx callback is only called _before_ an SSL connection is
* established, therefore it will not affect existing verified SSL
* connections already in the connection cache associated with this
* handle. normally you would set the ssl ctx function before making
* any transfers, and not use this option.
*/
rv = curl_easy_setopt(ch, CURLOPT_FRESH_CONNECT, 1L);
/* second try: retrieve page using cacerts' certificate -> will succeed
* load the certificate by installing a function doing the necessary
* "modifications" to the SSL CONTEXT just before link init

View File

@ -62,79 +62,9 @@ NULL
.SH PROTOCOLS
All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.
.SH EXAMPLE
.nf
/* OpenSSL specific */
See cacertinmem.c in docs/examples directory for usage example.
#include <openssl/ssl.h>
#include <curl/curl.h>
#include <stdio.h>
static CURLcode sslctx_function(CURL *curl, void *sslctx, void *parm)
{
X509_STORE *store;
X509 *cert=NULL;
BIO *bio;
char *mypem = /* example CA cert PEM - shortened */
"-----BEGIN CERTIFICATE-----\\n"
"MIIHPTCCBSWgAwIBAgIBADANBgkqhkiG9w0BAQQFADB5MRAwDgYDVQQKEwdSb290\\n"
"IENBMR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNB\\n"
"IENlcnQgU2lnbmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRA\\n"
"Y2FjZXJ0Lm9yZzAeFw0wMzAzMzAxMjI5NDlaFw0zMzAzMjkxMjI5NDlaMHkxEDAO\\n"
"GCSNe9FINSkYQKyTYOGWhlC0elnYjyELn8+CkcY7v2vcB5G5l1YjqrZslMZIBjzk\\n"
"zk6q5PYvCdxTby78dOs6Y5nCpqyJvKeyRKANihDjbPIky/qbn3BHLt4Ui9SyIAmW\\n"
"omTxJBzcoTWcFbLUvFUufQb1nA5V9FrWk9p2rSVzTMVD\\n"
"-----END CERTIFICATE-----\\n";
/* get a BIO */
bio=BIO_new_mem_buf(mypem, -1);
/* use it to read the PEM formatted certificate from memory into an
* X509 structure that SSL can use
*/
PEM_read_bio_X509(bio, &cert, 0, NULL);
if(cert == NULL)
printf("PEM_read_bio_X509 failed...\\n");
/* get a pointer to the X509 certificate store (which may be empty) */
store=SSL_CTX_get_cert_store((SSL_CTX *)sslctx);
/* add our certificate to this store */
if(X509_STORE_add_cert(store, cert)==0)
printf("error adding certificate\\n");
/* decrease reference counts */
X509_free(cert);
BIO_free(bio);
/* all set to go */
return CURLE_OK;
}
int main(void)
{
CURL * ch;
CURLcode rv;
rv=curl_global_init(CURL_GLOBAL_ALL);
ch=curl_easy_init();
rv=curl_easy_setopt(ch, CURLOPT_SSLCERTTYPE, "PEM");
rv=curl_easy_setopt(ch, CURLOPT_SSL_VERIFYPEER, 1L);
rv=curl_easy_setopt(ch, CURLOPT_URL, "https://www.example.com/");
/* Retrieve page using cacerts' certificate -> will succeed
* load the certificate by installing a function doing the necessary
* "modifications" to the SSL CONTEXT just before link init
*/
rv=curl_easy_setopt(ch, CURLOPT_SSL_CTX_FUNCTION, *sslctx_function);
rv=curl_easy_perform(ch);
if(rv==CURLE_OK)
printf("*** transfer succeeded ***\\n");
else
printf("*** transfer failed ***\\n");
curl_easy_cleanup(ch);
curl_global_cleanup();
return rv;
}
.fi
https://curl.haxx.se/libcurl/c/cacertinmem.html
.SH AVAILABILITY
Added in 7.11.0 for OpenSSL. Added in 7.42.0 for wolfSSL/CyaSSL. Added in
7.54.0 for mbedTLS. Other SSL backends not supported.