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/* 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.c: Generic encryption support.
*/
#include "vim.h"
#if defined(FEAT_CRYPT) || defined(PROTO)
/*
* Optional encryption support.
* Mohsin Ahmed, mosh@sasi.com, 1998-09-24
* Based on zip/crypt sources.
* Refactored by David Leadbeater, 2014.
*
* 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* Blowfish addition originally made by Mohsin Ahmed,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.
*/
typedef struct {
char *name; /* encryption name as used in 'cryptmethod' */
char *magic; /* magic bytes stored in file header */
int salt_len; /* length of salt, or 0 when not using salt */
int seed_len; /* length of seed, or 0 when not using salt */
#ifdef CRYPT_NOT_INPLACE
int works_inplace; /* encryption/decryption can be done in-place */
#endif
int whole_undofile; /* whole undo file is encrypted */
/* Optional function pointer for a self-test. */
int (* self_test_fn)();
// Function pointer for initializing encryption/description.
void (* init_fn)(cryptstate_T *state, char_u *key,
char_u *salt, int salt_len, char_u *seed, int seed_len);
/* Function pointers for encoding/decoding from one buffer into another.
* Optional, however, these or the _buffer ones should be configured. */
void (*encode_fn)(cryptstate_T *state, char_u *from, size_t len,
char_u *to);
void (*decode_fn)(cryptstate_T *state, char_u *from, size_t len,
char_u *to);
/* Function pointers for encoding and decoding, can buffer data if needed.
* Optional (however, these or the above should be configured). */
long (*encode_buffer_fn)(cryptstate_T *state, char_u *from, size_t len,
char_u **newptr);
long (*decode_buffer_fn)(cryptstate_T *state, char_u *from, size_t len,
char_u **newptr);
/* Function pointers for in-place encoding and decoding, used for
* crypt_*_inplace(). "from" and "to" arguments will be equal.
* These may be the same as decode_fn and encode_fn above, however an
* algorithm may implement them in a way that is not interchangeable with
* the crypt_(en|de)code() interface (for example because it wishes to add
* padding to files).
* This method is used for swap and undo files which have a rigid format.
*/
void (*encode_inplace_fn)(cryptstate_T *state, char_u *p1, size_t len,
char_u *p2);
void (*decode_inplace_fn)(cryptstate_T *state, char_u *p1, size_t len,
char_u *p2);
} cryptmethod_T;
/* index is method_nr of cryptstate_T, CRYPT_M_* */
static cryptmethod_T cryptmethods[CRYPT_M_COUNT] = {
/* PK_Zip; very weak */
{
"zip",
"VimCrypt~01!",
0,
0,
#ifdef CRYPT_NOT_INPLACE
TRUE,
#endif
FALSE,
NULL,
crypt_zip_init,
crypt_zip_encode, crypt_zip_decode,
NULL, NULL,
crypt_zip_encode, crypt_zip_decode,
},
/* Blowfish/CFB + SHA-256 custom key derivation; implementation issues. */
{
"blowfish",
"VimCrypt~02!",
8,
8,
#ifdef CRYPT_NOT_INPLACE
TRUE,
#endif
FALSE,
blowfish_self_test,
crypt_blowfish_init,
crypt_blowfish_encode, crypt_blowfish_decode,
NULL, NULL,
crypt_blowfish_encode, crypt_blowfish_decode,
},
/* Blowfish/CFB + SHA-256 custom key derivation; fixed. */
{
"blowfish2",
"VimCrypt~03!",
8,
8,
#ifdef CRYPT_NOT_INPLACE
TRUE,
#endif
TRUE,
blowfish_self_test,
crypt_blowfish_init,
crypt_blowfish_encode, crypt_blowfish_decode,
NULL, NULL,
crypt_blowfish_encode, crypt_blowfish_decode,
},
/* NOTE: when adding a new method, use some random bytes for the magic key,
* to avoid that a text file is recognized as encrypted. */
};
#define CRYPT_MAGIC_LEN 12 /* cannot change */
static char crypt_magic_head[] = "VimCrypt~";
/*
* Return int value for crypt method name.
* 0 for "zip", the old method. Also for any non-valid value.
* 1 for "blowfish".
* 2 for "blowfish2".
*/
int
crypt_method_nr_from_name(char_u *name)
{
int i;
for (i = 0; i < CRYPT_M_COUNT; ++i)
if (STRCMP(name, cryptmethods[i].name) == 0)
return i;
return 0;
}
/*
* Get the crypt method used for a file from "ptr[len]", the magic text at the
* start of the file.
* Returns -1 when no encryption used.
*/
int
crypt_method_nr_from_magic(char *ptr, int len)
{
int i;
if (len < CRYPT_MAGIC_LEN)
return -1;
for (i = 0; i < CRYPT_M_COUNT; i++)
if (memcmp(ptr, cryptmethods[i].magic, CRYPT_MAGIC_LEN) == 0)
return i;
i = (int)STRLEN(crypt_magic_head);
if (len >= i && memcmp(ptr, crypt_magic_head, i) == 0)
emsg(_("E821: File is encrypted with unknown method"));
return -1;
}
#ifdef CRYPT_NOT_INPLACE
/*
* Return TRUE if the crypt method for "method_nr" can be done in-place.
*/
int
crypt_works_inplace(cryptstate_T *state)
{
return cryptmethods[state->method_nr].works_inplace;
}
#endif
/*
* Get the crypt method for buffer "buf" as a number.
*/
int
crypt_get_method_nr(buf_T *buf)
{
return crypt_method_nr_from_name(*buf->b_p_cm == NUL ? p_cm : buf->b_p_cm);
}
/*
* Return TRUE when the buffer uses an encryption method that encrypts the
* whole undo file, not only the text.
*/
int
crypt_whole_undofile(int method_nr)
{
return cryptmethods[method_nr].whole_undofile;
}
/*
* Get crypt method specifc length of the file header in bytes.
*/
int
crypt_get_header_len(int method_nr)
{
return CRYPT_MAGIC_LEN
+ cryptmethods[method_nr].salt_len
+ cryptmethods[method_nr].seed_len;
}
/*
* Set the crypt method for buffer "buf" to "method_nr" using the int value as
* returned by crypt_method_nr_from_name().
*/
void
crypt_set_cm_option(buf_T *buf, int method_nr)
{
free_string_option(buf->b_p_cm);
buf->b_p_cm = vim_strsave((char_u *)cryptmethods[method_nr].name);
}
/*
* If the crypt method for the current buffer has a self-test, run it and
* return OK/FAIL.
*/
int
crypt_self_test(void)
{
int method_nr = crypt_get_method_nr(curbuf);
if (cryptmethods[method_nr].self_test_fn == NULL)
return OK;
return cryptmethods[method_nr].self_test_fn();
}
/*
* Allocate a crypt state and initialize it.
*/
cryptstate_T *
crypt_create(
int method_nr,
char_u *key,
char_u *salt,
int salt_len,
char_u *seed,
int seed_len)
{
cryptstate_T *state = (cryptstate_T *)alloc((int)sizeof(cryptstate_T));
state->method_nr = method_nr;
cryptmethods[method_nr].init_fn(state, key, salt, salt_len, seed, seed_len);
return state;
}
/*
* Allocate a crypt state from a file header and initialize it.
* Assumes that header contains at least the number of bytes that
* crypt_get_header_len() returns for "method_nr".
*/
cryptstate_T *
crypt_create_from_header(
int method_nr,
char_u *key,
char_u *header)
{
char_u *salt = NULL;
char_u *seed = NULL;
int salt_len = cryptmethods[method_nr].salt_len;
int seed_len = cryptmethods[method_nr].seed_len;
if (salt_len > 0)
salt = header + CRYPT_MAGIC_LEN;
if (seed_len > 0)
seed = header + CRYPT_MAGIC_LEN + salt_len;
return crypt_create(method_nr, key, salt, salt_len, seed, seed_len);
}
/*
* Read the crypt method specific header data from "fp".
* Return an allocated cryptstate_T or NULL on error.
*/
cryptstate_T *
crypt_create_from_file(FILE *fp, char_u *key)
{
int method_nr;
int header_len;
char magic_buffer[CRYPT_MAGIC_LEN];
char_u *buffer
|