mirror of
https://github.com/vim/vim
synced 2025-03-17 23:37:08 +01:00
aae583441b
Problem: Decrypting with libsodium may fail if the library changes.
Solution: Add parameters used to the encrypted file header. (Christian
Brabandt, closes #12279)
154 lines
3.2 KiB
C
154 lines
3.2 KiB
C
/* vi:set ts=8 sts=4 sw=4 noet:
|
|
*
|
|
* VIM - Vi IMproved by Bram Moolenaar
|
|
*
|
|
* Do ":help uganda" in Vim to read copying and usage conditions.
|
|
* Do ":help credits" in Vim to see a list of people who contributed.
|
|
* See README.txt for an overview of the Vim source code.
|
|
*/
|
|
|
|
/*
|
|
* crypt_zip.c: Zip encryption support.
|
|
*/
|
|
#include "vim.h"
|
|
|
|
#if defined(FEAT_CRYPT) || defined(PROTO)
|
|
/*
|
|
* 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.
|
|
*/
|
|
|
|
// Need a type that should be 32 bits. 64 also works but wastes space.
|
|
typedef unsigned int u32_T; // int is at least 32 bits
|
|
|
|
// The state of encryption, referenced by cryptstate_T.
|
|
typedef struct {
|
|
u32_T keys[3];
|
|
} zip_state_T;
|
|
|
|
|
|
static u32_T crc_32_table[256];
|
|
|
|
/*
|
|
* Fill the CRC table, if not done already.
|
|
*/
|
|
static void
|
|
make_crc_tab(void)
|
|
{
|
|
u32_T s, t, v;
|
|
static int done = FALSE;
|
|
|
|
if (done)
|
|
return;
|
|
for (t = 0; t < 256; t++)
|
|
{
|
|
v = t;
|
|
for (s = 0; s < 8; s++)
|
|
v = (v >> 1) ^ ((v & 1) * (u32_T)0xedb88320L);
|
|
crc_32_table[t] = v;
|
|
}
|
|
done = TRUE;
|
|
}
|
|
|
|
#define CRC32(c, b) (crc_32_table[((int)(c) ^ (b)) & 0xff] ^ ((c) >> 8))
|
|
|
|
/*
|
|
* Return the next byte in the pseudo-random sequence.
|
|
*/
|
|
#define DECRYPT_BYTE_ZIP(keys, t) \
|
|
{ \
|
|
short_u temp = (short_u)keys[2] | 2; \
|
|
t = (int)(((unsigned)(temp * (temp ^ 1U)) >> 8) & 0xff); \
|
|
}
|
|
|
|
/*
|
|
* Update the encryption keys with the next byte of plain text.
|
|
*/
|
|
#define UPDATE_KEYS_ZIP(keys, c) do { \
|
|
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)); \
|
|
} while (0)
|
|
|
|
/*
|
|
* Initialize for encryption/decryption.
|
|
*/
|
|
int
|
|
crypt_zip_init(
|
|
cryptstate_T *state,
|
|
char_u *key,
|
|
crypt_arg_T *arg UNUSED)
|
|
{
|
|
char_u *p;
|
|
zip_state_T *zs;
|
|
|
|
zs = ALLOC_ONE(zip_state_T);
|
|
if (zs == NULL)
|
|
return FAIL;
|
|
state->method_state = zs;
|
|
|
|
make_crc_tab();
|
|
zs->keys[0] = 305419896L;
|
|
zs->keys[1] = 591751049L;
|
|
zs->keys[2] = 878082192L;
|
|
for (p = key; *p != NUL; ++p)
|
|
UPDATE_KEYS_ZIP(zs->keys, (int)*p);
|
|
|
|
return OK;
|
|
}
|
|
|
|
/*
|
|
* Encrypt "from[len]" into "to[len]".
|
|
* "from" and "to" can be equal to encrypt in place.
|
|
*/
|
|
void
|
|
crypt_zip_encode(
|
|
cryptstate_T *state,
|
|
char_u *from,
|
|
size_t len,
|
|
char_u *to,
|
|
int last UNUSED)
|
|
{
|
|
zip_state_T *zs = state->method_state;
|
|
size_t i;
|
|
int ztemp, t;
|
|
|
|
for (i = 0; i < len; ++i)
|
|
{
|
|
ztemp = from[i];
|
|
DECRYPT_BYTE_ZIP(zs->keys, t);
|
|
UPDATE_KEYS_ZIP(zs->keys, ztemp);
|
|
to[i] = t ^ ztemp;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Decrypt "from[len]" into "to[len]".
|
|
*/
|
|
void
|
|
crypt_zip_decode(
|
|
cryptstate_T *state,
|
|
char_u *from,
|
|
size_t len,
|
|
char_u *to,
|
|
int last UNUSED)
|
|
{
|
|
zip_state_T *zs = state->method_state;
|
|
size_t i;
|
|
short_u temp;
|
|
|
|
for (i = 0; i < len; ++i)
|
|
{
|
|
temp = (short_u)zs->keys[2] | 2;
|
|
temp = (int)(((unsigned)(temp * (temp ^ 1U)) >> 8) & 0xff);
|
|
UPDATE_KEYS_ZIP(zs->keys, to[i] = from[i] ^ temp);
|
|
}
|
|
}
|
|
|
|
#endif // FEAT_CRYPT
|