/*
 * checkpop.c
 *
 * Supposedly generic code to check user authentication credentials through
 * POP3 authentication. Designed as an authentication mechanism for use with
 * PHP SpamAssasin MySQL (http://www.peregrinehw.com/downloads/).
 *
 * Tested to work fine with GNU POP3d, should work fine with other popper
 * daemons, if it dosnt please send a bug report.
 *
 * Bug reports to: tom+cpop@rooted.net
 * 
 */

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

#define PORT 110

#define ERR -1
#define POK 0 

int main(int argc, char **argv)
{

	int sockfd;
	int pwrf=0;
	int i=0,c=0;

	char popbuf[80];
	char tmpbuf[2];
	char quit[20];

	char *user, *pass;

	struct sockaddr_in server;
	struct hostent *he;

			
	if(argc < 3)
	{	
		return(ERR);
	}

	
	if ((user = (char *) malloc(20)) == NULL)
	{
		printf("malloc failed\n");
		exit(ERR);
	}

	if ((pass = (char *) malloc(20)) == NULL) 
	{
		printf("malloc failed\n");
		exit(ERR);
	}


	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if(sockfd < 0)
		perror("Error opening socket");

	
	he = gethostbyname(argv[1]);
	if(he == NULL)
		perror("gethostbyname() failed");


	memset(&server, 0x00, sizeof(struct sockaddr_in));	

	memcpy(&server.sin_addr, he->h_addr_list[0], he->h_length);	
	
	server.sin_family = AF_INET;
	server.sin_port = htons(110);

	
	if(connect(sockfd, (struct sockaddr *) &server, sizeof(server)) == -1)
	{
		printf("Error connecting");
		exit(ERR);
	}
	

	memset(user, 0x00, 20);
	memset(pass, 0x00, 20);
	memset(quit, 0x00, 20);
	memset(popbuf, 0x00, sizeof(popbuf));

	snprintf(user, 20, "USER %s\r\n", argv[2]);
	snprintf(pass, 20, "PASS %s\r\n", argv[3]);

	sprintf(quit, "QUIT\r\n");

	write(sockfd, user, strlen(user)); 
	write(sockfd, pass, strlen(pass)); 


	while( (read(sockfd, tmpbuf, 1) ) != -1)
	{
		i++;

		if(tmpbuf[0] == '\x0A')
		{
			
			if(strstr(popbuf, "-ERR") != NULL)
			{
				if(user != NULL)
					free(user);
				if(pass != NULL)
					free(user);


				write(sockfd, quit, strlen(quit)); 
				close(sockfd);
				exit(ERR);
			}

			else if(strstr(popbuf, "Password required for") != NULL)
			{
				pwrf = 1;
			}

			else if((pwrf == 1) && strstr(popbuf, "+OK") != NULL)
			{
				if(user != NULL)
					free(user);
				if(pass != NULL)
					free(user);

				write(sockfd, quit, strlen(quit)); 
				close(sockfd);
				exit(POK);
			}
			
			
			i=0;

			memset(popbuf, 0x00, sizeof(popbuf));
		}

		popbuf[i] = tmpbuf[0];
			
	}


	if(user != NULL)
		free(user);
	if(pass != NULL)
		free(user);

	write(sockfd, quit, strlen(quit)); 
	close(sockfd);	
	return(ERR);
}