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// Optional encryption support.
// Mohsin Ahmed, mosh@sasi.com, 98-09-24
// Based on zip/crypt sources.
//
// NOTE FOR USA: Since 2000 exporting this code from the USA is allowed to
// most countries. There are a few exceptions, but that still should not be a
// problem since this code was originally created in Europe and India.
//
// Blowfish addition originally made by Mohsin Ahmed,
// http://www.cs.albany.edu/~mosh 2010-03-14
// Based on blowfish by Bruce Schneier (http://www.schneier.com/blowfish.html)
// and sha256 by Christophe Devine.
#include "vim.h"
#include "misc2.h"
#include "blowfish.h"
#include "ex_getln.h"
#include "message.h"
#include "option.h"
static void make_crc_tab(void);
static uint32_t crc_32_tab[256];
// Fills the CRC table.
static void make_crc_tab(void)
{
uint32_t s;
uint32_t t;
uint32_t v;
static bool done = false;
if (done) {
return;
}
for (t = 0; t < 256; t++) {
v = t;
for (s = 0; s < 8; s++) {
v = (v >> 1) ^ ((v & 1) * (uint32_t)0xedb88320L);
}
crc_32_tab[t] = v;
}
done = true;
}
#define CRC32(c, b) (crc_32_tab[((int)(c) ^ (b)) & 0xff] ^ ((c) >> 8))
static uint32_t keys[3]; // keys defining the pseudo-random sequence
// Returns the next byte in the pseudo-random sequence.
#define DECRYPT_BYTE_ZIP(t) { \
uint16_t temp; \
temp = (uint16_t)keys[2] | 2; \
t = (int)(((unsigned)(temp * (temp ^ 1U)) >> 8) & 0xff); \
}
// Updates the encryption keys with the next byte of plain text.
#define UPDATE_KEYS_ZIP(c) { \
keys[0] = CRC32(keys[0], (c)); \
keys[1] += keys[0] & 0xff; \
keys[1] = keys[1] * 134775813L + 1; \
keys[2] = CRC32(keys[2], (int)(keys[1] >> 24)); \
}
static int crypt_busy = 0;
static uint32_t saved_keys[3];
static int saved_crypt_method;
int crypt_method_from_string(char_u *s)
{
return *s == 'b' ? 1 : 0;
}
int get_crypt_method(buf_T *buf)
{
return crypt_method_from_string(*buf->b_p_cm == NUL ? p_cm : buf->b_p_cm);
}
void set_crypt_method(buf_T *buf, int method)
{
free_string_option(buf->b_p_cm);
buf->b_p_cm = vim_strsave((char_u *)(method == 0 ? "zip" : "blowfish"));
}
void crypt_push_state(void)
{
if (crypt_busy == 1) {
// Save the state
if (use_crypt_method == 0) {
saved_keys[0] = keys[0];
saved_keys[1] = keys[1];
saved_keys[2] = keys[2];
} else {
bf_crypt_save();
}
saved_crypt_method = use_crypt_method;
} else if (crypt_busy > 1) {
EMSG2(_(e_intern2), "crypt_push_state()");
}
crypt_busy++;
}
void crypt_pop_state(void)
{
crypt_busy--;
if (crypt_busy == 1) {
use_crypt_method = saved_crypt_method;
if (use_crypt_method == 0) {
keys[0] = saved_keys[0];
keys[1] = saved_keys[1];
keys[2] = saved_keys[2];
} else {
bf_crypt_restore();
}
}
}
void crypt_encode(char_u *from, size_t len, char_u *to)
{
size_t i;
int ztemp;
int t;
if (use_crypt_method == 0) {
for (i = 0; i < len; i++) {
ztemp = from[i];
DECRYPT_BYTE_ZIP(t);
UPDATE_KEYS_ZIP(ztemp);
to[i] = t ^ ztemp;
}
} else {
bf_crypt_encode(from, len, to);
}
}
void crypt_decode(char_u *ptr, long len)
{
char_u *p;
if (use_crypt_method == 0) {
for (p = ptr; p < ptr + len; p++) {
uint16_t temp;
temp = (uint16_t)keys[2] | 2;
temp = (int)(((unsigned)(temp * (temp ^ 1U)) >> 8) & 0xff);
UPDATE_KEYS_ZIP(*p ^= temp);
}
} else {
bf_crypt_decode(ptr, len);
}
}
void crypt_init_keys(char_u *passwd)
{
if ((passwd != NULL) && (*passwd != NUL)) {
if (use_crypt_method == 0) {
char_u *p;
make_crc_tab();
keys[0] = 305419896L;
keys[1] = 591751049L;
keys[2] = 878082192L;
for (p = passwd; *p != NUL; p++) {
UPDATE_KEYS_ZIP((int)*p);
}
} else {
bf_crypt_init_keys(passwd);
}
}
}
void free_crypt_key(char_u *key)
{
char_u *p;
if (key != NULL) {
for (p = key; *p != NUL; p++) {
*p = 0;
}
free(key);
}
}
char_u *get_crypt_key(int store, int twice)
{
char_u *p1;
char_u *p2 = NULL;
int round;
for (round = 0;; round++) {
cmdline_star = TRUE;
cmdline_row = msg_row;
char_u *prompt = (round == 0)
? (char_u *) _("Enter encryption key: ")
: (char_u *) _("Enter same key again: ");
p1 = getcmdline_prompt(NUL, prompt, 0, EXPAND_NOTHING, NULL);
cmdline_star = FALSE;
if (p1 == NULL) {
break;
}
if (round == twice) {
if ((p2 != NULL) && (STRCMP(p1, p2) != 0)) {
MSG(_("Keys don't match!"));
free_crypt_key(p1);
free_crypt_key(p2);
p2 = NULL;
round = -1; // Do it again
continue;
}
if (store) {
set_option_value((char_u *) "key", 0L, p1, OPT_LOCAL);
free_crypt_key(p1);
p1 = curbuf->b_p_key;
}
break;
}
p2 = p1;
}
// Since the user typed this, no need to wait for return.
if (msg_didout) {
msg_putchar('\n');
}
need_wait_return = FALSE;
msg_didout = FALSE;
free_crypt_key(p2);
return p1;
}
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