1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
/****************************************************************
* *
* Copyright 2009, 2014 Fidelity Information Services, Inc *
* *
* This source code contains the intellectual property *
* of its copyright holder(s), and is made available *
* under a license. If you do not know the terms of *
* the license, please stop and do not read further. *
* *
****************************************************************/
#define _FILE_OFFSET_BITS 64 /* Needed to compile gpgme client progs also with large file support */
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdarg.h>
#include <assert.h>
#include <fcntl.h>
#include <errno.h>
#include <dlfcn.h>
#include <sys/mman.h>
#include <sys/stat.h> /* BYPASSOK -- see above */
#include <sys/types.h>
#include <gpgme.h> /* gpgme functions */
#include <gpg-error.h> /* gcry*_err_t */
#include <libconfig.h>
#include "gtmxc_types.h" /* xc_string, xc_status_t and other callin interfaces xc_fileid */
#include "gtmcrypt_util.h"
#include "gtmcrypt_interface.h" /* Function prototypes for gtmcrypt*.* functions */
#include "gtmcrypt_ref.h"
#include "gtmcrypt_dbk_ref.h"
#include "gtmcrypt_sym_ref.h"
#include "gtmcrypt_pk_ref.h"
GBLDEF passwd_entry_t *gtmcrypt_pwent;
GBLDEF gpgme_ctx_t pk_crypt_ctx;
void gc_pk_scrub_passwd()
{
/* Nullify the key strings, so that any generated cores will not contain the unencrypted keys */
gc_freeup_pwent(gtmcrypt_pwent);
/* Finally release the gpgme context */
if (NULL != pk_crypt_ctx)
gpgme_release(pk_crypt_ctx);
}
/* This function is called whenever gpg needs the passphrase with which the secret key is encrypted. In this case, the passphrase
* is obtained from the ENVIRONMENT VARIABLE - $gtm_passwd or by invoking the mumps engine during the "gtmcrypt_init()".
* In either ways, it's guaranteed that when this function is called, the passphrase is already set in the global variable.
*/
int gc_pk_crypt_passphrase_callback(void *opaque, const char *uid_hint, const char *passphrase_info, int last_was_bad, int fd)
{
int write_ret, len;
assert(0 != fd);
assert(NULL != gtmcrypt_pwent->passwd);
len = STRLEN(gtmcrypt_pwent->passwd);
write_ret = write(fd, gtmcrypt_pwent->passwd, len);
if (len == write_ret)
{
write_ret = write(fd, "\n", 1);
if (1 == write_ret)
return 0;
}
/* Problem with one of the writes so let gpgme know */
return -1;
}
/* Given the structure that holds the plain data, this function reads through the structure and retrieves the plain text. We
* also return the number of bytes actually read from the structure.
*/
int gc_pk_crypt_retrieve_plain_text(gpgme_data_t plain_data, unsigned char *plain_text)
{
int ret;
assert(NULL != plain_text);
/* Clear the temporary buffer */
memset(plain_text, 0, SYMMETRIC_KEY_MAX);
gpgme_data_seek(plain_data, 0, SEEK_SET);
ret = (int)gpgme_data_read(plain_data, plain_text, SYMMETRIC_KEY_MAX);
return ret;
}
/* This is currently necessary to work around what seems to be a gpgme issue in not clearing the plaintext keys
* from the C stack (shows up in a core dump otherwise). When gpgme is fixed, this code can be removed.
* The size of lclarray (8K) is determined purely from experimentation on all platforms.
*/
int gc_pk_scrub_plaintext_keys_from_c_stack()
{
char lclarray[8192];
memset(lclarray, 0, SIZEOF(lclarray));
return 0;
}
/* This function tries to decrypt the cipher file (the file containing the symmetric key with which the database is encrypted).
* It's assumed that the context is initialized and is set with the appropriate passphrase callback. The cipher_file
* should contain the fully qualified path of the encrypted database key file. Also, plain text is supposed to be allocated with
* sufficient space to hold the decrypted text.
*/
gpgme_error_t gc_pk_get_decrypted_key(const char *cipher_file, unsigned char *plain_text, int *plain_text_length)
{
gpgme_error_t err;
gpgme_data_t cipher_data = NULL, plain_data = NULL;
gpg_err_code_t ecode;
char null_buffer[SYMMETRIC_KEY_MAX];
assert(NULL != cipher_file);
assert(NULL != plain_text);
assert(NULL != pk_crypt_ctx);
assert(0 != STRLEN(cipher_file));
/* Convert the cipher content in the cipher file into in-memory content.
* This in-memory content is stored in gpgme_data_t structure.
*/
err = gpgme_data_new_from_file(&cipher_data, cipher_file, 1);
if (!err)
{
err = gpgme_data_new(&plain_data);
if (!err)
{ /* Try decrypting the cipher content with the context.
* The decrypted content will also be stored in gpgme_data_t structure.
*/
err = gpgme_op_decrypt(pk_crypt_ctx, cipher_data, plain_data);
if (!err) /* Once decrypted, the plain text has to be obtained from the plain_data structure. */
*plain_text_length = gc_pk_crypt_retrieve_plain_text(plain_data, plain_text);
gc_pk_scrub_plaintext_keys_from_c_stack();
}
}
ecode = gpgme_err_code(err);
if (0 != ecode)
{
switch (ecode)
{
case GPG_ERR_BAD_PASSPHRASE:
UPDATE_ERROR_STRING("Incorrect password or error while obtaining password");
break;
case GPG_ERR_ENOENT:
UPDATE_ERROR_STRING("Encryption key file " STR_ARG " not found", ELLIPSIZE(cipher_file));
break;
case GPG_ERR_EACCES:
UPDATE_ERROR_STRING("Encryption key file " STR_ARG " not accessible", ELLIPSIZE(cipher_file));
break;
case GPG_ERR_ENAMETOOLONG:
UPDATE_ERROR_STRING("Path, or a component of the path, to encryption key file " STR_ARG
" is too long", ELLIPSIZE(cipher_file));
break;
default:
UPDATE_ERROR_STRING("Error while accessing key file " STR_ARG ": %s", ELLIPSIZE(cipher_file),
gpgme_strerror(err));
break;
}
} else
{
assert((0 == plain_text_length) || (NULL != plain_data));
}
if (NULL != plain_data)
{ /* Scrub plaintext data before releasing it */
assert(SYMMETRIC_KEY_MAX == SIZEOF(null_buffer));
memset(null_buffer, 0, SYMMETRIC_KEY_MAX);
assert((0 != ecode) || (0 != plain_text_length) || memcmp(plain_text, null_buffer, SYMMETRIC_KEY_MAX));
gpgme_data_write(plain_data, null_buffer, SYMMETRIC_KEY_MAX);
gpgme_data_release(plain_data);
}
if (NULL != cipher_data)
gpgme_data_release(cipher_data);
return ecode;
}
int gc_pk_gpghome_has_permissions()
{
char pathname[GTM_PATH_MAX], *ptr;
int gnupghome_set, perms;
/* See if GNUPGHOME is set in the environment */
if (!(ptr = getenv(GNUPGHOME)))
{ /* $GNUPGHOME is not set, use $HOME/.gnupg as the GPG home directory */
gnupghome_set = FALSE;
if (!(ptr = getenv(HOME)))
{
UPDATE_ERROR_STRING(ENV_UNDEF_ERROR, HOME);
return -1;
}
SNPRINTF(pathname, GTM_PATH_MAX, "%s/%s", ptr, DOT_GNUPG);
} else
{
if (0 == strlen(ptr))
{
UPDATE_ERROR_STRING(ENV_EMPTY_ERROR, GNUPGHOME);
return -1;
}
gnupghome_set = TRUE;
strcpy(pathname, ptr);
}
if (-1 != (perms = access(pathname, R_OK | X_OK)))
return 0;
else if (EACCES == errno)
{
if (gnupghome_set)
{
UPDATE_ERROR_STRING("No read permissions on $%s", GNUPGHOME);
} else
UPDATE_ERROR_STRING("No read permissions on $%s/%s", HOME, DOT_GNUPG);
} else /* Some other error */
UPDATE_ERROR_STRING("Cannot stat on " STR_ARG " - %d", ELLIPSIZE(pathname), errno);
return -1;
}
|
