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#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <sys/select.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <sys/errno.h>
#include <sys/stat.h>
#include <time.h>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <map>
#include <string>
using namespace std;
#define PICA_REGISTRAR_PORT 2299
#define READ_BUF_SIZE 4096
#define WRITE_BUF_SIZE 8192
#define BAN_THRESHOLD_SECS 60
char read_buf[READ_BUF_SIZE];
char write_buf[WRITE_BUF_SIZE];
struct ban_info
{
unsigned int reg_count;
time_t last_reg;
};
static std::map<in_addr_t, struct ban_info> banmap;
unsigned int current_id = 30000;
int read_CSR(int client_socket, int *bytes_read)
{
int pos = 0, ret;
int disconnect_flag = 0;
do
{
ret = recv(client_socket, read_buf + pos, READ_BUF_SIZE - 1 - pos, 0);
if (ret > 0)
pos += ret;
else
{
disconnect_flag = 1;
if (ret < 0)
perror("recv");
}
read_buf[pos + 1] = '\0';
*bytes_read = pos;
}
while(pos < READ_BUF_SIZE && !disconnect_flag && !std::strstr(read_buf, "-----END CERTIFICATE REQUEST-----"));
return disconnect_flag;
}
int store_CSR(string csr_filename, int csr_size)
{
FILE *csr_temp;
int ret;
csr_temp = fopen(csr_filename.c_str(), "w");
if (!csr_temp)
{
perror("fopen");
return 1;
}
ret = fwrite(read_buf, csr_size, 1, csr_temp);
if (ret != 1)
{
perror("fwrite");
fclose(csr_temp);
remove(csr_filename.c_str());
return 1;
}
fclose(csr_temp);
return 0;
}
int send_cert(int client_socket, string cert_filename)
{
int cert_size, ret, bs;
FILE *cert;
//get file size
struct stat st;
if (stat(cert_filename.c_str(), &st))
return 1;
cert_size = st.st_size;
cert = fopen(cert_filename.c_str(), "r");
if (!cert)
{
perror("fopen");
return 1;
}
//read
ret = fread(write_buf, cert_size, 1, cert);
if (ret !=1)
{
perror("fread");
fclose(cert);
return 1;
}
//send
bs = 0;
do
{
ret = send(client_socket, write_buf + bs, cert_size - bs, MSG_NOSIGNAL);
if (ret <=0)
break;
bs += ret;
} while (bs < cert_size);
if (bs < cert_size)
return 1;
return 0;
}
//check if we should ban this IP
int IP_ban(struct sockaddr_in *a)
{
time_t time_now =time(NULL);
if (banmap[a->sin_addr.s_addr].reg_count >=3 && (time_now - banmap[a->sin_addr.s_addr].last_reg ) < BAN_THRESHOLD_SECS)
{
banmap[a->sin_addr.s_addr].reg_count++;
printf("IP %.16s temporarily banned\n", inet_ntoa(a->sin_addr));
return 1;
}
return 0;
}
//add successfully registered client to ban info
void baninfo_update(struct sockaddr_in *a)
{
time_t time_now =time(NULL);
if ((time_now - banmap[a->sin_addr.s_addr].last_reg ) > BAN_THRESHOLD_SECS)
banmap[a->sin_addr.s_addr].reg_count = 0;
banmap[a->sin_addr.s_addr].reg_count++;
banmap[a->sin_addr.s_addr].last_reg = time_now;
}
int main(int argc, char *argv[])
{
int s, client_socket, ret, pos, disconnect_flag, bytes_read, cert_size;
struct sockaddr_in sd, sc;
s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
memset(&sd,0,sizeof(sd));
sd.sin_family = AF_INET;
sd.sin_addr.s_addr = INADDR_ANY;
sd.sin_port = htons(PICA_REGISTRAR_PORT);
ret = bind(s,(struct sockaddr*)&sd,sizeof(sd));
ret = listen(s, 60);
while (1)
{
socklen_t sockaddr_size = sizeof(sc);
memset(&sc, 0, sizeof(sc));
client_socket = accept(s, (struct sockaddr*)&sc, &sockaddr_size);
if (client_socket >= 0)
{
if (IP_ban(&sc))
{
close(client_socket);
continue;
}
disconnect_flag = read_CSR(client_socket, &bytes_read);
if (disconnect_flag)
{
shutdown(client_socket, SHUT_RDWR);
close(client_socket);
continue;
}
std::string filename = (string("/tmp/CSR-") + inet_ntoa(sc.sin_addr) );
if (store_CSR(filename, bytes_read))
{
shutdown(client_socket, SHUT_RDWR);
close(client_socket);
continue;
}
char current_id_str[256];
sprintf(current_id_str, "%u", current_id);
std::string cert_filename = (string)(current_id_str) + ".pem";
std::string sign_command = (string)"openssl ca -config ca_config.txt -utf8 -subj /CN=" + current_id_str + "\\#tester -batch -notext -out " + cert_filename + " -in " + filename;
puts(sign_command.c_str());//debug
system(sign_command.c_str());
if (send_cert(client_socket, cert_filename))
goto freeres_1;
current_id++;
baninfo_update(&sc);
freeres_1:
remove(cert_filename.c_str());
freeres_2:
remove(filename.c_str());
freeres_3:
shutdown(client_socket, SHUT_RDWR);
close(client_socket);
}
else
perror("accept");
}
return 0;
}
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