1 /*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel (at) haxx.se>, et al. 9 * 10 * This software is licensed as described in the file COPYING, which 11 * you should have received as part of this distribution. The terms 12 * are also available at https://curl.haxx.se/docs/copyright.html. 13 * 14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell 15 * copies of the Software, and permit persons to whom the Software is 16 * furnished to do so, under the terms of the COPYING file. 17 * 18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY 19 * KIND, either express or implied. 20 * 21 ***************************************************************************/ 22 23 /* <DESC> 24 * POP3 example using TLS 25 * </DESC> 26 */ 27 28 #include <stdio.h> 29 #include <curl/curl.h> 30 31 /* This is a simple example showing how to retrieve mail using libcurl's POP3 32 * capabilities. It builds on the pop3-retr.c example adding transport 33 * security to protect the authentication details from being snooped. 34 * 35 * Note that this example requires libcurl 7.20.0 or above. 36 */ 37 38 int main(void) 39 { 40 CURL *curl; 41 CURLcode res = CURLE_OK; 42 43 curl = curl_easy_init(); 44 if(curl) { 45 /* Set username and password */ 46 curl_easy_setopt(curl, CURLOPT_USERNAME, "user"); 47 curl_easy_setopt(curl, CURLOPT_PASSWORD, "secret"); 48 49 /* This will retrieve message 1 from the user's mailbox */ 50 curl_easy_setopt(curl, CURLOPT_URL, "pop3://pop.example.com/1"); 51 52 /* In this example, we'll start with a plain text connection, and upgrade 53 * to Transport Layer Security (TLS) using the STLS command. Be careful of 54 * using CURLUSESSL_TRY here, because if TLS upgrade fails, the transfer 55 * will continue anyway - see the security discussion in the libcurl 56 * tutorial for more details. */ 57 curl_easy_setopt(curl, CURLOPT_USE_SSL, (long)CURLUSESSL_ALL); 58 59 /* If your server doesn't have a valid certificate, then you can disable 60 * part of the Transport Layer Security protection by setting the 61 * CURLOPT_SSL_VERIFYPEER and CURLOPT_SSL_VERIFYHOST options to 0 (false). 62 * curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L); 63 * curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L); 64 * 65 * That is, in general, a bad idea. It is still better than sending your 66 * authentication details in plain text though. Instead, you should get 67 * the issuer certificate (or the host certificate if the certificate is 68 * self-signed) and add it to the set of certificates that are known to 69 * libcurl using CURLOPT_CAINFO and/or CURLOPT_CAPATH. See docs/SSLCERTS 70 * for more information. */ 71 curl_easy_setopt(curl, CURLOPT_CAINFO, "/path/to/certificate.pem"); 72 73 /* Since the traffic will be encrypted, it is very useful to turn on debug 74 * information within libcurl to see what is happening during the 75 * transfer */ 76 curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L); 77 78 /* Perform the retr */ 79 res = curl_easy_perform(curl); 80 81 /* Check for errors */ 82 if(res != CURLE_OK) 83 fprintf(stderr, "curl_easy_perform() failed: %s\n", 84 curl_easy_strerror(res)); 85 86 /* Always cleanup */ 87 curl_easy_cleanup(curl); 88 } 89 90 return (int)res; 91 } 92
