[titbang]

This program extracts certificates from OpenVPN configuration files.

Code:

#include <iostream>
#include <string.h>
#include <stdio.h>

using namespace std;

int i = 0;

string buffer, filename, ca, cert, key, auth;

struct _tags { const char* first; const char* last; };

const char* files[] = { "ca.crt", "client.crt", "client.key", "ta.key" };

_tags tags[] = {
    { "<ca>", "</ca>" },
    { "<cert>", "</cert>" },
    { "<key>", "</key>" },
    { "<tls-auth>", "</tls-auth>" }
};

string string_between( string str, const string& from, const string& to ) {
    size_t first = str.find(from);
    size_t last = str.find(to);
    return( str.substr ( first+from.size(),last-first-to.size()));
}

int read_file_to_buffer( string filename )
{
    char line[12];
    FILE* pFile = fopen( filename.c_str(), "r" );
    if( pFile != NULL ) {
        while( fgets( line, sizeof( line ), pFile ) ) {
            buffer.append( line );
        }
    } else {
        return 1;
    }
    return 0;
}

int write_buffer_to_file( string buffer, string filename )
{
    FILE* pFile = fopen( filename.c_str(), "w" );
    if( pFile != NULL ) {
        fwrite (buffer.c_str(), sizeof(char), buffer.size(), pFile);
        fclose(pFile);
    } else {
        return 1;
    }
    return 0;
}

int append_found_tags_to_main( int type )
{
    FILE* pFile = fopen( filename.c_str(), "a+" );
    if( pFile != NULL ) {
        if( type == 1 ) {
            fprintf( pFile, "\nca %s\r\ncert %s\r\nkey %s\r\n",
                files[0], files[1], files[2] );
        } else {
            fprintf( pFile, "\nca %s\r\ncert %s\r\nkey %s\r\ntls-auth %s\r\n",
                files[0], files[1], files[2], files[3] );
        }
        fclose(pFile);
    } else {
        return 1;
    }
    return 0;
}

int extract_tags( )
{
    while (buffer.find(tags[i].first) != std::string::npos )
    {
        if( i == 0 ) {
            ca = string_between( buffer, tags[i].first, tags[i].last);
        } else if( i == 1 ) {
            cert = string_between( buffer, tags[i].first, tags[i].last);
        } else if( i == 2 ) {
            key = string_between( buffer, tags[i].first, tags[i].last);
        } else if( i == 3 ) {
            auth = string_between( buffer, tags[i].first, tags[i].last);
        } else {
            return 1;
        }
        i++;
    }
    return 0;
}

int write_tags( )
{
    if( !ca.empty() && !cert.empty() && !key.empty() ) {
        write_buffer_to_file( ca, files[0] );
        write_buffer_to_file( cert, files[1] );
        write_buffer_to_file( key, files[2] );
        if( !auth.empty() ) {
            write_buffer_to_file( auth, files[3] );
            append_found_tags_to_main( 0 );
        } else {
            append_found_tags_to_main( 1 );
            return 1;
        }
    } else {
        return 2;
    }
    return 0;
}

int main(int argc, char* argv[])
{
    if( argv[1] == NULL ) {
        printf("cert2conf<: You need to specify a valid filename to extract from.\r\n");
        return 1;
    } else {
        if( argv[2] != NULL && argv[3] != NULL && argv[4] != NULL && argv[5] != NULL) {
            files[0] = argv[2];
            files[1] = argv[3];
            files[2] = argv[4];
            files[3] = argv[5];
        }
        filename = argv[1];
    }
    read_file_to_buffer( argv[1] );
    if( buffer.empty()){
        printf("cert2conf<: You need to specify a valid filename to extract from.\r\n");
        return 2;
    }
    if( extract_tags() == 0 ) {
        int result = write_tags();
        if( result == 0 ) {
            printf("cert2conf<: All certificates and keys successfully extracted.\r\n");
        } else if( result == 1 ) {
            printf("cert2conf<: Unable to find a TLS auth key, but this isn't exactly an error.\r\n");
        } else if( result == 2 ) {
            printf("cert2conf<: Something went totally wrong with the certificate files.\r\n");
        }
    } else {
        printf("cert2conf<: Something went wrong while extracting the tags.\r\n");
        return 3;
    }
    return 0;
}