diff options
Diffstat (limited to 'src/main.c')
| -rw-r--r-- | src/main.c | 555 |
1 files changed, 555 insertions, 0 deletions
diff --git a/src/main.c b/src/main.c new file mode 100644 index 0000000..46a5277 --- /dev/null +++ b/src/main.c @@ -0,0 +1,555 @@ +/* Inexact source code package. + * + * Written in 2019 by <ben@hackade.org>. + * + * To the extent possible under law, the author have dedicated all copyright + * and related and neighboring rights to this software to the public domain + * worldwide. This software is distributed without any warranty. + * + * You should have received a copy of the CC0 Public Domain Dedication along with + * this software. If not, see <http://creativecommons.org/publicdomain/zero/1.0/>. + */ + +#include <errno.h> +#include <getopt.h> +#include <limits.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include "argtable3.h" +#include "inexact.h" +#include "tests.h" + +/* global arg_xxx structs */ +struct arg_lit *help, *version, *gen, *dencrypt, *ddecrypt, *test, *base64, *weak, + *nopassword, *symmetric; +struct arg_file *seckey, *pubkey, *infile, *outfile; +struct arg_end *end; +struct arg_int *taglen, *noncelen, *cipherlen; + +int main(int argc, char *argv[]) { + /* the global arg_xxx structs are initialised within the argtable */ + void *argtable[] = { + help = arg_litn("h", "help", 0, 1, "display this help and exit"), + version = arg_litn("v", "version", 0, 1, "display version info and exit"), + gen = arg_litn("g", "genkeys", 0, 1, "generate keys"), + dencrypt = arg_litn("e", "encrypt", 0, 1, "encrypt data"), + ddecrypt = arg_litn("d", "decrypt", 0, 1, "decrypt data"), + symmetric = arg_litn("s", "symmetric", 0, 1, "symmetric encryption with password"), + seckey = arg_filen("k", "seckey", "secretkey", 0, 1, "secret key file"), + pubkey = arg_filen("p", "pubkey", "publickey", 0, 1, "public key iles"), + taglen = arg_intn("t", "taglen", "<64,128,192,256>", 0, 1, "authentication message tag length in bits (default: 256)"), + noncelen = arg_intn("n", "noncelen", "<n>", 0, 1, "random nonce length in bytes (default: 32, must be >= 16)"), + cipherlen = arg_intn("c", "cipherlen", "<n>", 0, 1, "set random nonce length for <n> bytes output ciphertext size"), + base64 = arg_litn(NULL, "base64", 0, 1, "use base64 format without transformation"), + test = arg_litn(NULL, "test", 0, 1, "test crypto and encoding internal functions"), + nopassword = arg_litn(NULL, "no-password", 0, 1, "generate secret key without password"), + weak = arg_litn("w", "weak", 0, 1, "use weak length for nonce and auth tag (-n 4 -t 32)"), + infile = arg_filen("i", "input-file", "<infile>", 0, 1, "input file (default: stdin)"), + outfile = arg_filen("o", "output-file", "<outfile>", 0, 1, "output file (default: stdout)"), + end = arg_end(20), + }; + + int exitcode = 0; + const char progname[] = "inexact"; + const char ver[] = "beta 1.0"; + FILE *fo = NULL; + + int nerrors; + nerrors = arg_parse(argc, argv, argtable); + + /* special case: '--help' takes precedence over error reporting */ + if (help->count > 0) { + printf("Usage: %s", progname); + arg_print_syntax(stdout, argtable, "\n"); + printf( + "INadvisable EXperimental Asymmetric Crypto Tool, by " + "<ben@hackade.org>.\n\n"); + arg_print_glossary(stdout, argtable, " %-25s %s\n"); + exitcode = 0; + goto exit; + } + + /* If the parser returned any errors then display them and exit */ + if (nerrors > 0) { + /* Display the error details contained in the arg_end struct.*/ + arg_print_errors(stdout, end, progname); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + + /* check if an action is specified */ + int action_count = gen->count + ddecrypt->count + dencrypt->count + + version->count + help->count + test->count; + if (action_count == 0) { + printf("Missing parameters.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + + if (version->count == 1) { + printf("version: %s\n", ver); + exitcode = 0; + goto exit; + } + + if (test->count > 0) { + exitcode = test_all(); + goto exit; + } + + /* check if more than one action is specified */ + if (action_count > 1) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + + if (symmetric->count == 1) { + if (gen->count == 1) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + if (pubkey->count == 1) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + if (seckey->count == 1) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + if (nopassword->count == 1) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + } + + /* check if a secret key is specified */ + if (seckey->count == 0 && symmetric->count == 0) { + printf("Missing secret key file operand.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + + /* check if public key is specified */ + if (pubkey->count == 0 && symmetric->count == 0) { + printf("Missing public key file operand.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + + int nopassword_flag = (nopassword->count == 1); + + /* generate action */ + if (gen->count == 1) { + if (base64->count == 1) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + if (infile->count == 1) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + if (outfile->count == 1) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + if (taglen->count == 1) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + if (noncelen->count == 1) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + if (access(seckey->filename[0], F_OK) != -1) { + char ch; + printf("Overwrite '%s' ? ", seckey->filename[0]); + int res = scanf("%c", &ch); + if ((ch != 'Y' && ch != 'y') || res == 0) { + exitcode = 1; + goto exit; + } + } + if (access(pubkey->filename[0], F_OK) != -1) { + char ch; + printf("Overwrite '%s' ? ", pubkey->filename[0]); + int res = scanf(" %c", &ch); + if ((ch != 'Y' && ch != 'y') || res == 0) { + exitcode = 1; + goto exit; + } + } + + return generate_keys(seckey->filename[0], pubkey->filename[0], + nopassword_flag); + } + + /* read input infile data */ + unsigned char *data = NULL; + int data_len = 0; + + if (infile->count == 0) { + /* read stdin */ + int cap = 4096, len = 0; + data = malloc(cap * sizeof(unsigned char)); + if (data == NULL) { + printf("malloc %d bytes failed.\n", cap); + exitcode = 1; + goto exit; + } + int c = 0; + do { + c = fgetc(stdin); + data[len] = c; + if (++len == cap) { + cap *= 2; + data = realloc(data, cap * sizeof(unsigned char)); + if (data == NULL) { + printf("realloc %d bytes failed.\n", cap); + exitcode = 1; + goto exit; + } + } + } while (!feof(stdin)); + fclose(stdin); + data = realloc(data, len * sizeof(unsigned char)); + if (data == NULL) { + printf("realloc %d bytes failed.\n", cap); + exitcode = 1; + goto exit; + } + data[len - 1] = '\0'; + data_len = len - 1; + } else if (access(infile->filename[0], F_OK) == -1) { + printf("Input file '%s' not found.\n", infile->filename[0]); + exitcode = 1; + goto exit; + } else { + FILE *fi = fopen(infile->filename[0], "rb"); + if (fi == NULL) { + printf("open file '%s' failed: %s.\n", infile->filename[0], + strerror(errno)); + exitcode = 1; + goto exit; + } + int rsb = fseek(fi, 0L, SEEK_END); + if (rsb != 0) { + printf("seek to end file '%s' failed: %s.\n", infile->filename[0], + strerror(errno)); + fclose(fi); + exitcode = 1; + goto exit; + } + data_len = ftell(fi); + if (data_len == -1) { + printf("tell file '%s' failed: %s.\n", infile->filename[0], + strerror(errno)); + fclose(fi); + exitcode = 1; + goto exit; + } + int rse = fseek(fi, 0L, SEEK_SET); + if (rse != 0) { + printf("seek file to begin'%s' failed: %s.\n", infile->filename[0], + strerror(errno)); + fclose(fi); + exitcode = 1; + goto exit; + } + data = malloc(data_len); + if (data == NULL) { + printf("malloc %d bytes failed.\n", data_len); + fclose(fi); + exitcode = 1; + goto exit; + } + size_t readed = fread(data, 1, data_len, fi); + if (readed != data_len) { + printf("read file '%s' failed: %s.\n", infile->filename[0], + strerror(errno)); + fclose(fi); + exitcode = 1; + goto exit; + } + fclose(fi); + } + + /* check size limitation for input data (32 bits) */ + if (data_len > 0xbfffffff) { + printf("Size of data too big.\n"); + exitcode = 1; + goto exit; + } + + int auth_tag_len = 32; + if (taglen->count == 1) { + if (ddecrypt->count == 1) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + if (dencrypt->count == 0) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + int tag_len_value = taglen->ival[0]; + if (tag_len_value != 64 && tag_len_value != 128 && + tag_len_value != 192 && tag_len_value != 256) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } else { + auth_tag_len = tag_len_value / 8; + } + } + + /* output file */ + if (outfile->count == 0) { + fo = stdout; + } else { + fo = fopen(outfile->filename[0], "wb"); + if (fo == NULL) { + printf("open file '%s' failed: %s.\n", outfile->filename[0], + strerror(errno)); + exitcode = 1; + goto exit; + } + } + + const int rand_nonce_len_min = 16; + int rand_nonce_len = 32; + if (noncelen->count == 1) { + if (ddecrypt->count == 1) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + if (dencrypt->count == 0) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + if (cipherlen->count == 1) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + int noncelen_value = noncelen->ival[0]; + if (noncelen_value < rand_nonce_len_min) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } else { + rand_nonce_len = noncelen_value; + } + } + + int base64_transformation = (base64->count == 0); + if (cipherlen->count == 1) { + if (dencrypt->count == 0 || noncelen->count == 1 || base64->count == 1) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + size_t cipherlen_b64_value = cipherlen->ival[0]; + size_t cipherlen_value = cipherlen_b64_value * 3 / 4; + + size_t part0_len = 9; + size_t part1_len = data_len + auth_tag_len + rand_nonce_len; + size_t total_encrypted_len = part0_len + part1_len; + size_t total_encrypted_len_without_rand1 = + total_encrypted_len - rand_nonce_len; + + if (symmetric->count == 1) { + total_encrypted_len_without_rand1 = + total_encrypted_len_without_rand1 + 64; + } + + size_t rand_nonce_len_needed = + cipherlen_value - total_encrypted_len_without_rand1; + + if (total_encrypted_len_without_rand1 > cipherlen_value || + rand_nonce_len_needed < rand_nonce_len_min) { + unsigned long total_cipherlen_b64_min = + (total_encrypted_len_without_rand1 + rand_nonce_len_min) * 4 / + 3; + printf("Insufficient nonce length, cipherlen must be > %lu\n", + total_cipherlen_b64_min); + exitcode = 2; + goto exit; + } else { + rand_nonce_len = rand_nonce_len_needed; + } + } + + if (weak->count == 1) { + if (dencrypt->count == 0 || noncelen->count == 1 || taglen->count == 1 || + cipherlen->count == 1) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + rand_nonce_len = 4; + auth_tag_len = 4; + } + + if (dencrypt->count == 1) { + unsigned char secretkey[32] = {0}; + unsigned char publickey[32] = {0}; + unsigned char salt[32] = {0}; + unsigned char *psalt = NULL; + + if (symmetric->count == 1) { + if (get_symmetrickeys(salt, secretkey, publickey) != 0) { + printf("Symmetric keys generation failed.\n"); + exitcode = 1; + goto exit; + } + psalt = &salt[0]; + } else { + if (access(seckey->filename[0], F_OK) == -1) { + printf("Secret key file '%s' not found.\n", + seckey->filename[0]); + exitcode = 1; + goto exit; + } + if (get_seckey(seckey->filename[0], secretkey, NULL) == 1) { + printf("File '%s': invalid key.\n", seckey->filename[0]); + exitcode = 1; + goto exit; + } + if (access(pubkey->filename[0], F_OK) == -1) { + printf("Public key file '%s' not found.\n", + pubkey->filename[0]); + exitcode = 1; + goto exit; + } + if (get_pubkey(pubkey->filename[0], publickey) == 1) { + printf("File '%s': invalid key.\n", pubkey->filename[0]); + exitcode = 1; + goto exit; + } + } + size_t encrypted_len = 0; + unsigned char *encrypted = encrypt_data( + secretkey, publickey, psalt, data, data_len, rand_nonce_len, + auth_tag_len, base64_transformation, &encrypted_len); + if (encrypted == NULL) { + printf("Encryption failed.\n"); + exitcode = 1; + goto exit; + } + fwrite(encrypted, 1, encrypted_len, fo); + if (base64_transformation) { + fwrite("\n", 1, 1, fo); + } + fflush(fo); + memset(encrypted, 0, encrypted_len); + memset(secretkey, 0, 32); + memset(publickey, 0, 32); + memset(data, 0, data_len); + free(encrypted); + } + + if (ddecrypt->count == 1) { + unsigned char secretkey[32] = {0}; + unsigned char publickey[32] = {0}; + + if (base64->count == 1) { + printf("Invalid options.\n"); + printf("Try '%s --help' for more information.\n", progname); + exitcode = 1; + goto exit; + } + if (symmetric->count == 1) { + if (check_get_symmetrickeys(data, data_len, secretkey, publickey) != + 0) { + exitcode = 1; + goto exit; + } + } else { + if (access(seckey->filename[0], F_OK) == -1) { + printf("Secret key file '%s' not found.\n", + seckey->filename[0]); + exitcode = 1; + goto exit; + } + if (get_seckey(seckey->filename[0], secretkey, NULL) == 1) { + printf("File '%s': invalid key.\n", seckey->filename[0]); + exitcode = 1; + goto exit; + } + if (access(pubkey->filename[0], F_OK) == -1) { + printf("Public key file '%s' not found.\n", + pubkey->filename[0]); + exitcode = 1; + goto exit; + } + if (get_pubkey(pubkey->filename[0], publickey) == 1) { + printf("File '%s': invalid key.\n", pubkey->filename[0]); + exitcode = 1; + goto exit; + } + } + + size_t decrypted_len = 0; + unsigned char *decrypted = + decrypt_data(secretkey, publickey, data, data_len, + (symmetric->count == 1), &decrypted_len); + + if (decrypted == NULL || decrypted_len == 0) { + printf("Decryption failed.\n"); + exitcode = 1; + goto exit; + } + fwrite(decrypted, 1, decrypted_len, fo); + fflush(fo); + memset(decrypted, 0, decrypted_len); + memset(secretkey, 0, 32); + memset(publickey, 0, 32); + memset(data, 0, data_len); + free(decrypted); + } + +exit: + if (fo != NULL) fclose(fo); + + /* deallocate each non-null entry in argtable[] */ + arg_freetable(argtable, sizeof(argtable) / sizeof(argtable[0])); + return exitcode; +} |