129 lines
3.2 KiB
C
Executable File
129 lines
3.2 KiB
C
Executable File
/**
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* gcc -g -o client client.c -lssl -lcrypt -lcrypto
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <unistd.h>
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#include <malloc.h>
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#include <string.h>
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#include <sys/socket.h>
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#include <resolv.h>
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#include <netdb.h>
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#include <openssl/ssl.h>
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#include <openssl/err.h>
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#define FAIL -1
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int OpenConnection(const char *hostname, int port)
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{
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int sd;
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struct hostent *host;
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struct sockaddr_in addr;
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if ((host = gethostbyname(hostname)) == NULL)
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{
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printf("Eroor: %s\n", hostname);
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perror(hostname);
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abort();
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}
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sd = socket(PF_INET, SOCK_STREAM, 0);
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bzero(&addr, sizeof(addr));
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addr.sin_family = AF_INET;
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addr.sin_port = htons(port);
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addr.sin_addr.s_addr = *(long*) (host->h_addr);
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if (connect(sd, (struct sockaddr*) &addr, sizeof(addr)) != 0)
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{
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close(sd);
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perror(hostname);
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abort();
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}
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return sd;
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}
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SSL_CTX* InitCTX(void)
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{
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SSL_METHOD *method;
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SSL_CTX *ctx;
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OpenSSL_add_all_algorithms(); /* Load cryptos, et.al. */
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SSL_load_error_strings(); /* Bring in and register error messages */
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// method = SSLv3_client_method(); /* Create new client-method instance */
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method = TLSv1_2_client_method();
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ctx = SSL_CTX_new(method); /* Create new context */
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if (ctx == NULL)
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{
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ERR_print_errors_fp(stderr);
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printf("Eroor: %s\n", stderr);
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abort();
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}
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return ctx;
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}
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void ShowCerts(SSL* ssl)
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{
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X509 *cert;
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char *line;
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cert = SSL_get_peer_certificate(ssl); /* Get certificates (if available) */
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if (cert != NULL)
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{
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printf("Server certificates:\n");
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line = X509_NAME_oneline(X509_get_subject_name(cert), 0, 0);
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printf("Subject: %s\n", line);
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free(line);
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line = X509_NAME_oneline(X509_get_issuer_name(cert), 0, 0);
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printf("Issuer: %s\n", line);
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free(line);
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X509_free(cert);
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}
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else
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printf("No certificates.\n");
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}
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int main(int count, char *strings[])
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{
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SSL_CTX *ctx;
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int server;
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SSL *ssl;
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char buf[1024];
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int bytes;
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char *hostname, *portnum;
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if (count != 3)
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{
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printf("usage: %s <hostname> <portnum>\n", strings[0]);
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exit(0);
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}
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SSL_library_init();
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hostname = strings[1];
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portnum = strings[2];
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ctx = InitCTX();
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server = OpenConnection(hostname, atoi(portnum));
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ssl = SSL_new(ctx); /* create new SSL connection state */
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SSL_set_fd(ssl, server); /* attach the socket descriptor */
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TLSv1_2_client_method();
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if (SSL_connect(ssl) == FAIL) /* perform the connection */
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{
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printf("Eroor: %s\n", stderr);
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ERR_print_errors_fp(stderr);
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}
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else
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{
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char *msg = "HelloWorld";
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printf("Connected with %s encryption\n", SSL_get_cipher(ssl));
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ShowCerts(ssl); /* get any certs */
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SSL_write(ssl, msg, strlen(msg)); /* encrypt & send message */
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bytes = SSL_read(ssl, buf, sizeof(buf)); /* get reply & decrypt */
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buf[bytes] = 0;
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printf("Received: \"%s\"\n", buf);
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SSL_free(ssl); /* release connection state */
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}
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close(server); /* close socket */
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SSL_CTX_free(ctx); /* release context */
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return 0;
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}
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