166 lines
4.0 KiB
C
166 lines
4.0 KiB
C
/*
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* file.c - File writing functionality
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* The author licenses this file
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* to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing,
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* software distributed under the License is distributed on an
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* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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* KIND, either express or implied. See the License for the
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* specific language governing permissions and limitations
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* under the License.
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*/
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#include "file.h"
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#include "config.h"
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#include "base64.h"
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#include <time.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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/* Generate a safe directory name to store ONE emails files into. This is
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* done to prevent someone from guessing the directory names. THe first part
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* is the date in ISO format, in case you want to have a shell script cleaning
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* the directory every once in a while.
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*/
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char* generate_safe_dirname(){
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/* Get time */
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time_t rawtime;
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struct tm *info;
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time( &rawtime );
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info = localtime( &rawtime );
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#define TIME_LEN 30
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char datestr[TIME_LEN];
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memset(datestr, 0, TIME_LEN);
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strftime(datestr, TIME_LEN, "%FT%T%z", info);
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/* Get data from urandom to be secure. I mean from what I
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* know it should be, but I'm not a crypto expert. If you have doubts
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* and know how I should do that, PLEASE TELL ME! The man pages told me
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* to do so!
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*/
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int randie[3];
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int random_fd = open("/dev/random", O_RDONLY);
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if (random_fd < 0){
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perror("Failed to open /dev/urandom");
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return NULL;
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}else{
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size_t randie_len = 0;
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while (randie_len < sizeof(randie)){
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ssize_t result = read(random_fd, randie + randie_len, sizeof(randie) - randie_len);
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if (result < 0){
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perror("Failed to read from /dev/urandom");
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close(random_fd);
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return NULL;
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}
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randie_len += result;
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}
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close(random_fd);
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}
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size_t dir_len = TIME_LEN + 50 + strlen(directory);
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char * dir_id = malloc(dir_len+1);
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memset(dir_id, 0, dir_len+1 );
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snprintf(dir_id,dir_len, "%s/%s%i%i%i/",directory, datestr,
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randie[0], randie[1], randie[2]);
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#undef TIME_LEN
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return dir_id;
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}
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int base64_decode_file(const char* directory, const struct email_t* mail){
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if(!mail->base64_encoded){
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return -1;
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}
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if(directory == NULL || mail == NULL || mail->file_info.name == NULL){
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/* I don't know how I should call that file! */
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return 0;
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}
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size_t dec_len = 0;
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unsigned char* decoded = base64_decode(
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((unsigned char*)mail->message+mail->body_offset),
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(mail->message_length-mail->body_offset),
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&dec_len);
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if(decoded == NULL){
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fprintf(stderr, "Failed to decode base64 message\n");
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return -1;
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}
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size_t fn_len = strlen(mail->file_info.name) + strlen(directory) + 1;
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char* filename = malloc(fn_len);
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if(filename == NULL){
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free(decoded);
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return -1;
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}
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memset(filename, 0, fn_len);
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strcat(filename, directory);
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strcat(filename, mail->file_info.name);
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bool exists = false;
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for(size_t i = 0; i < 10; i++){
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exists = file_exists(filename);
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if(exists){
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free(filename);
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fn_len = strlen(mail->file_info.name) +
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strlen(directory) + 20;
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filename = malloc(fn_len);
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snprintf(filename, fn_len, "%s%i-%s",directory,
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rand(), mail->file_info.name);
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}
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}
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if(exists){
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/* What?*/
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fprintf(stderr,"Failed to create unique file name!\n");
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free(filename);
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free(decoded);
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return -1;
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}
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FILE* outfile = fopen(filename, "w+");
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if(outfile == NULL){
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perror("Failed to open base64 out file");
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free(filename);
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free(decoded);
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return -1;
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}
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if(verbose){
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printf("Storing base64 file len %lu top [%s]\n",
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dec_len, decoded);
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}
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fwrite(decoded, dec_len, 1, outfile);
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fclose(outfile);
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free(filename);
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free(decoded);
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return 0;
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}
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bool file_exists(const char* filename){
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struct stat buffer;
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int exist = stat(filename,&buffer);
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if(exist >= 0){
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return true;
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} else{
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return false;
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}
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}
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