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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* Blowfish addition originally made by Mohsin Ahmed,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 */
int works_inplace; /* encryption/decryption can be done in-place */
int whole_undofile; /* whole undo file is encrypted */
/* Optional function pointer for a self-test. */
int (* self_test_fn)();
/* Function pointer for initializing encryption/decription. */
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,
TRUE,
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,
TRUE,
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,
TRUE,
TRUE,
blowfish_self_test,
crypt_blowfish_init,
crypt_blowfish_encode, crypt_blowfish_decode,
NULL, NULL,
crypt_blowfish_encode, crypt_blowfish_decode,
},
};
#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;
}
/*
* 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;
}
/*
* 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;
cryptstate_T *state;
if (fread(magic_buffer, CRYPT_MAGIC_LEN, 1, fp) != 1)
return NULL;
method_nr = crypt_method_nr_from_magic(magic_buffer, CRYPT_MAGIC_LEN);
if (method_nr < 0)
return NULL;
header_len = crypt_get_header_len(method_nr);
if ((buffer = alloc(header_len)) == NULL)
return NULL;
mch_memmove(buffer, magic_buffer, CRYPT_MAGIC_LEN);
if (header_len > CRYPT_MAGIC_LEN
&& fread(buffer + CRYPT_MAGIC_LEN,
header_len - CRYPT_MAGIC_LEN, 1, fp) != 1)
{
vim_free(buffer);
return NULL;
}
state = crypt_create_from_header(method_nr, key, buffer);
vim_free(buffer);
return state;
}
/*
* Allocate a cryptstate_T for writing and initialize it with "key".
* Allocates and fills in the header and stores it in "header", setting
* "header_len". The header may include salt and seed, depending on
* cryptmethod. Caller must free header.
* Returns the state or NULL on failure.
*/
cryptstate_T *
crypt_create_for_writing(
int method_nr,
char_u *key,
char_u **header,
int *header_len)
{
int len = crypt_get_header_len(method_nr);
char_u *salt = NULL;
char_u *seed = NULL;
int salt_len = cryptmethods[method_nr].salt_len;
int seed_len = cryptmethods[method_nr].seed_len;
cryptstate_T *state;
*header_len = len;
*header = alloc(len);
if (*header == NULL)
return NULL;
mch_memmove(*header, cryptmethods[method_nr].magic, CRYPT_MAGIC_LEN);
if (salt_len > 0 || seed_len > 0)
{
if (salt_len > 0)
salt = *header + CRYPT_MAGIC_LEN;
if (seed_len > 0)
seed = *header + CRYPT_MAGIC_LEN + salt_len;
/* TODO: Should this be crypt method specific? (Probably not worth
* it). sha2_seed is pretty bad for large amounts of entropy, so make
* that into something which is suitable for anything. */
sha2_seed(salt, salt_len, seed, seed_len);
}
state = crypt_create(method_nr, key, salt, salt_len, seed, seed_len);
if (state == NULL)
{
vim_free(*header);
*header = NULL;
}
return state;
}
/*
* Free the crypt state.
*/
void
crypt_free_state(cryptstate_T *state)
{
vim_free(state->method_state);
vim_free(state);
}
/*
* Encode "from[len]" and store the result in a newly allocated buffer, which
* is stored in "newptr".
* Return number of bytes in "newptr", 0 for need more or -1 on error.
*/
long
crypt_encode_alloc(
cryptstate_T *state,
char_u *from,
size_t len,
char_u **newptr)
{
cryptmethod_T *method = &cryptmethods[state->method_nr];
if (method->encode_buffer_fn != NULL)
/* Has buffer function, pass through. */
return method->encode_buffer_fn(state, from, len, newptr);
if (len == 0)
/* Not buffering, just return EOF. */
return (long)len;
*newptr = alloc((long)len);
if (*newptr == NULL)
return -1;
method->encode_fn(state, from, len, *newptr);
return (long)len;
}
/*
* Decrypt "ptr[len]" and store the result in a newly allocated buffer, which
* is stored in "newptr".
* Return number of bytes in "newptr", 0 for need more or -1 on error.
*/
long
crypt_decode_alloc(
cryptstate_T *state,
char_u *ptr,
long len,
char_u **newptr)
{
cryptmethod_T *method = &cryptmethods[state->method_nr];
if (method->decode_buffer_fn != NULL)
/* Has buffer function, pass through. */
return method->decode_buffer_fn(state, ptr, len, newptr);
if (len == 0)
/* Not buffering, just return EOF. */
return len;
*newptr = alloc(len);
if (*newptr == NULL)
return -1;
method->decode_fn(state, ptr, len, *newptr);
return len;
}
/*
* Encrypting "from[len]" into "to[len]".
*/
void
crypt_encode(
cryptstate_T *state,
char_u *from,
size_t len,
char_u *to)
{
cryptmethods[state->method_nr].encode_fn(state, from, len, to);
}
/*
* decryptin
8000
g "from[len]" into "to[len]".
*/
void
crypt_decode(
cryptstate_T *state,
char_u *from,
size_t len,
char_u *to)
{
cryptmethods[state->method_nr].decode_fn(state, from, len, to);
}
/*
* Simple inplace encryption, modifies "buf[len]" in place.
*/
void
crypt_encode_inplace(
cryptstate_T *state,
char_u *buf,
size_t len)
{
cryptmethods[state->method_nr].encode_inplace_fn(state, buf, len, buf);
}
/*
* Simple inplace decryption, modifies "buf[len]" in place.
*/
void
crypt_decode_inplace(
cryptstate_T *state,
char_u *buf,
size_t len)
{
cryptmethods[state->method_nr].decode_inplace_fn(state, buf, len, buf);
}
/*
* Free an allocated crypt key. Clear the text to make sure it doesn't stay
* in memory anywhere.
*/
void
crypt_free_key(char_u *key)
{
char_u *p;
if (key != NULL)
{
for (p = key; *p != NUL; ++p)
*p = 0;
vim_free(key);
}
}
/*
* Check the crypt method and give a warning if it's outdated.
*/
void
crypt_check_method(int method)
{
if (method < CRYPT_M_BF2)
{
msg_scroll = TRUE;
MSG(_("Warning: Using a weak encryption method; see :help 'cm'"));
}
}
void
crypt_check_current_method(void)
{
crypt_check_method(crypt_get_method_nr(curbuf));
}
/*
* Ask the user for a crypt key.
* When "store" is TRUE, the new key is stored in the 'key' option, and the
* 'key' option value is returned: Don't free it.
* When "store" is FALSE, the typed key is returned in allocated memory.
* Returns NULL on failure.
*/
char_u *
crypt_get_key(
int store,
int twice) /* Ask for the key twice. */
{
char_u *p1, *p2 = NULL;
int round;
for (round = 0; ; ++round)
{
cmdline_star = TRUE;
cmdline_row = msg_row;
p1 = getcmdline_prompt(NUL, round == 0
? (char_u *)_("Enter encryption key: ")
: (char_u *)_("Enter same key again: "), 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!"));
crypt_free_key(p1);
crypt_free_key(p2);
p2 = NULL;
round = -1; /* do it again */
continue;
}
if (store)
{
set_option_value((char_u *)"key", 0L, p1, OPT_LOCAL);
crypt_free_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;
crypt_free_key(p2);
return p1;
}
/*
* Append a message to IOb
3D1E
uff for the encryption/decryption method being used.
*/
void
crypt_append_msg(
buf_T *buf)
{
if (crypt_get_method_nr(buf) == 0)
STRCAT(IObuff, _("[crypted]"));
else
{
STRCAT(IObuff, "[");
STRCAT(IObuff, *buf->b_p_cm == NUL ? p_cm : buf->b_p_cm);
STRCAT(IObuff, "]");
}
}
#endif /* FEAT_CRYPT */