exim-encrypt-dlfunc/src/common.c

#define _GNU_SOURCE

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <sodium.h>
#include "common.h"

char *read_first_line(const char *filename) {
    FILE *stream;
    char *cipherstring;
    size_t len = 0;
    ssize_t nread;
    bool input_is_stdin = false;

    // open file (use stdin for '-')
    if (!strncmp(filename, "-", 1)) {
        stream = stdin;
        input_is_stdin = true;
    } else {
        stream = fopen(filename, "r");
        if (stream == NULL) {
            fprintf(stderr, "[ERROR] Error opening file %s\n\n", filename);
            exit(EXIT_FAILURE);
        }
    }

    nread = getline(&cipherstring, &len, stream);

    if (nread == -1 && !feof(stream)) {
        perror("getline: ");
    }
    if (input_is_stdin == false) {
        fclose(stream);
    }

    // remove trailing newline
    cipherstring[strcspn(cipherstring, "\r\n")] = 0;

    return cipherstring;
}

char *read_password_file(const char *filename, size_t keysize, size_t *length) {
    FILE *stream;
    char *contents;
    ssize_t nread;
    bool input_is_stdin = false;

    contents = malloc(keysize + 1);
    sodium_memzero(contents, keysize + 1);

    // open file (use stdin for '-')
    if (!strncmp(filename, "-", 1)) {
        stream = stdin;
        input_is_stdin = true;
    } else {
        stream = fopen(filename, "r");
        if (stream == NULL) {
            fprintf(stderr, "[ERROR] Error opening file %s\n\n", filename);
            exit(EXIT_FAILURE);
        }
    }

    nread = fread(contents, sizeof(char), keysize, stream);

    if (nread < 0) {
        fprintf(stderr, "[ERROR] reading from %s failed\n\n", filename);
        exit(EXIT_FAILURE);
    } else {
        *length = (size_t) nread;
    }

    if (input_is_stdin == false) {
        fclose(stream);
    }
    return contents;
}

int base64_decode_string(const char *input, unsigned char **outstring, size_t *outlen) {
    size_t input_len = strlen(input);
    size_t outmaxlen = input_len / 4 * 3;
    *outstring = malloc(outmaxlen * sizeof(unsigned char));
    return sodium_base642bin(*outstring, outmaxlen, (const char *) input, input_len,
                             NULL, outlen, NULL, sodium_base64_VARIANT_ORIGINAL);
}