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
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
|
/*
* module for PostgreSQL to access client SSL certificate information
*
* Written by Victor B. Wagner <vitus@cryptocom.ru>, Cryptocom LTD
* This file is distributed under BSD-style license.
*
* contrib/sslinfo/sslinfo.c
*/
#include "postgres.h"
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include <openssl/asn1.h>
#include "access/htup_details.h"
#include "funcapi.h"
#include "libpq/libpq-be.h"
#include "miscadmin.h"
#include "utils/builtins.h"
PG_MODULE_MAGIC;
static Datum X509_NAME_field_to_text(X509_NAME *name, text *fieldName);
static Datum X509_NAME_to_text(X509_NAME *name);
static Datum ASN1_STRING_to_text(ASN1_STRING *str);
/*
* Function context for data persisting over repeated calls.
*/
typedef struct
{
TupleDesc tupdesc;
} SSLExtensionInfoContext;
/*
* Indicates whether current session uses SSL
*
* Function has no arguments. Returns bool. True if current session
* is SSL session and false if it is local or non-ssl session.
*/
PG_FUNCTION_INFO_V1(ssl_is_used);
Datum
ssl_is_used(PG_FUNCTION_ARGS)
{
PG_RETURN_BOOL(MyProcPort->ssl_in_use);
}
/*
* Returns SSL version currently in use.
*/
PG_FUNCTION_INFO_V1(ssl_version);
Datum
ssl_version(PG_FUNCTION_ARGS)
{
if (MyProcPort->ssl == NULL)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(cstring_to_text(SSL_get_version(MyProcPort->ssl)));
}
/*
* Returns SSL cipher currently in use.
*/
PG_FUNCTION_INFO_V1(ssl_cipher);
Datum
ssl_cipher(PG_FUNCTION_ARGS)
{
if (MyProcPort->ssl == NULL)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(cstring_to_text(SSL_get_cipher(MyProcPort->ssl)));
}
/*
* Indicates whether current client provided a certificate
*
* Function has no arguments. Returns bool. True if current session
* is SSL session and client certificate is verified, otherwise false.
*/
PG_FUNCTION_INFO_V1(ssl_client_cert_present);
Datum
ssl_client_cert_present(PG_FUNCTION_ARGS)
{
PG_RETURN_BOOL(MyProcPort->peer != NULL);
}
/*
* Returns serial number of certificate used to establish current
* session
*
* Function has no arguments. It returns the certificate serial
* number as numeric or null if current session doesn't use SSL or if
* SSL connection is established without sending client certificate.
*/
PG_FUNCTION_INFO_V1(ssl_client_serial);
Datum
ssl_client_serial(PG_FUNCTION_ARGS)
{
Datum result;
Port *port = MyProcPort;
X509 *peer = port->peer;
ASN1_INTEGER *serial = NULL;
BIGNUM *b;
char *decimal;
if (!peer)
PG_RETURN_NULL();
serial = X509_get_serialNumber(peer);
b = ASN1_INTEGER_to_BN(serial, NULL);
decimal = BN_bn2dec(b);
BN_free(b);
result = DirectFunctionCall3(numeric_in,
CStringGetDatum(decimal),
ObjectIdGetDatum(0),
Int32GetDatum(-1));
OPENSSL_free(decimal);
return result;
}
/*
* Converts OpenSSL ASN1_STRING structure into text
*
* Converts ASN1_STRING into text, converting all the characters into
* current database encoding if possible. Any invalid characters are
* replaced by question marks.
*
* Parameter: str - OpenSSL ASN1_STRING structure. Memory management
* of this structure is responsibility of caller.
*
* Returns Datum, which can be directly returned from a C language SQL
* function.
*/
static Datum
ASN1_STRING_to_text(ASN1_STRING *str)
{
BIO *membuf;
size_t size;
char nullterm;
char *sp;
char *dp;
text *result;
membuf = BIO_new(BIO_s_mem());
if (membuf == NULL)
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("could not create OpenSSL BIO structure")));
(void) BIO_set_close(membuf, BIO_CLOSE);
ASN1_STRING_print_ex(membuf, str,
((ASN1_STRFLGS_RFC2253 & ~ASN1_STRFLGS_ESC_MSB)
| ASN1_STRFLGS_UTF8_CONVERT));
/* ensure null termination of the BIO's content */
nullterm = '\0';
BIO_write(membuf, &nullterm, 1);
size = BIO_get_mem_data(membuf, &sp);
dp = pg_any_to_server(sp, size - 1, PG_UTF8);
result = cstring_to_text(dp);
if (dp != sp)
pfree(dp);
if (BIO_free(membuf) != 1)
elog(ERROR, "could not free OpenSSL BIO structure");
PG_RETURN_TEXT_P(result);
}
/*
* Returns specified field of specified X509_NAME structure
*
* Common part of ssl_client_dn and ssl_issuer_dn functions.
*
* Parameter: X509_NAME *name - either subject or issuer of certificate
* Parameter: text fieldName - field name string like 'CN' or commonName
* to be looked up in the OpenSSL ASN1 OID database
*
* Returns result of ASN1_STRING_to_text applied to appropriate
* part of name
*/
static Datum
X509_NAME_field_to_text(X509_NAME *name, text *fieldName)
{
char *string_fieldname;
int nid,
index;
ASN1_STRING *data;
string_fieldname = text_to_cstring(fieldName);
nid = OBJ_txt2nid(string_fieldname);
if (nid == NID_undef)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid X.509 field name: \"%s\"",
string_fieldname)));
pfree(string_fieldname);
index = X509_NAME_get_index_by_NID(name, nid, -1);
if (index < 0)
return (Datum) 0;
data = X509_NAME_ENTRY_get_data(X509_NAME_get_entry(name, index));
return ASN1_STRING_to_text(data);
}
/*
* Returns specified field of client certificate distinguished name
*
* Receives field name (like 'commonName' and 'emailAddress') and
* returns appropriate part of certificate subject converted into
* database encoding.
*
* Parameter: fieldname text - will be looked up in OpenSSL object
* identifier database
*
* Returns text string with appropriate value.
*
* Throws an error if argument cannot be converted into ASN1 OID by
* OpenSSL. Returns null if no client certificate is present, or if
* there is no field with such name in the certificate.
*/
PG_FUNCTION_INFO_V1(ssl_client_dn_field);
Datum
ssl_client_dn_field(PG_FUNCTION_ARGS)
{
text *fieldname = PG_GETARG_TEXT_PP(0);
Datum result;
if (!(MyProcPort->peer))
PG_RETURN_NULL();
result = X509_NAME_field_to_text(X509_get_subject_name(MyProcPort->peer), fieldname);
if (!result)
PG_RETURN_NULL();
else
return result;
}
/*
* Returns specified field of client certificate issuer name
*
* Receives field name (like 'commonName' and 'emailAddress') and
* returns appropriate part of certificate subject converted into
* database encoding.
*
* Parameter: fieldname text - would be looked up in OpenSSL object
* identifier database
*
* Returns text string with appropriate value.
*
* Throws an error if argument cannot be converted into ASN1 OID by
* OpenSSL. Returns null if no client certificate is present, or if
* there is no field with such name in the certificate.
*/
PG_FUNCTION_INFO_V1(ssl_issuer_field);
Datum
ssl_issuer_field(PG_FUNCTION_ARGS)
{
text *fieldname = PG_GETARG_TEXT_PP(0);
Datum result;
if (!(MyProcPort->peer))
PG_RETURN_NULL();
result = X509_NAME_field_to_text(X509_get_issuer_name(MyProcPort->peer), fieldname);
if (!result)
PG_RETURN_NULL();
else
return result;
}
/*
* Equivalent of X509_NAME_oneline that respects encoding
*
* This function converts X509_NAME structure to the text variable
* converting all textual data into current database encoding.
*
* Parameter: X509_NAME *name X509_NAME structure to be converted
*
* Returns: text datum which contains string representation of
* X509_NAME
*/
static Datum
X509_NAME_to_text(X509_NAME *name)
{
BIO *membuf = BIO_new(BIO_s_mem());
int i,
nid,
count = X509_NAME_entry_count(name);
X509_NAME_ENTRY *e;
ASN1_STRING *v;
const char *field_name;
size_t size;
char nullterm;
char *sp;
char *dp;
text *result;
if (membuf == NULL)
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("could not create OpenSSL BIO structure")));
(void) BIO_set_close(membuf, BIO_CLOSE);
for (i = 0; i < count; i++)
{
e = X509_NAME_get_entry(name, i);
nid = OBJ_obj2nid(X509_NAME_ENTRY_get_object(e));
if (nid == NID_undef)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not get NID for ASN1_OBJECT object")));
v = X509_NAME_ENTRY_get_data(e);
field_name = OBJ_nid2sn(nid);
if (field_name == NULL)
field_name = OBJ_nid2ln(nid);
if (field_name == NULL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("could not convert NID %d to an ASN1_OBJECT structure", nid)));
BIO_printf(membuf, "/%s=", field_name);
ASN1_STRING_print_ex(membuf, v,
((ASN1_STRFLGS_RFC2253 & ~ASN1_STRFLGS_ESC_MSB)
| ASN1_STRFLGS_UTF8_CONVERT));
}
/* ensure null termination of the BIO's content */
nullterm = '\0';
BIO_write(membuf, &nullterm, 1);
size = BIO_get_mem_data(membuf, &sp);
dp = pg_any_to_server(sp, size - 1, PG_UTF8);
result = cstring_to_text(dp);
if (dp != sp)
pfree(dp);
if (BIO_free(membuf) != 1)
elog(ERROR, "could not free OpenSSL BIO structure");
PG_RETURN_TEXT_P(result);
}
/*
* Returns current client certificate subject as one string
*
* This function returns distinguished name (subject) of the client
* certificate used in the current SSL connection, converting it into
* the current database encoding.
*
* Returns text datum.
*/
PG_FUNCTION_INFO_V1(ssl_client_dn);
Datum
ssl_client_dn(PG_FUNCTION_ARGS)
{
if (!(MyProcPort->peer))
PG_RETURN_NULL();
return X509_NAME_to_text(X509_get_subject_name(MyProcPort->peer));
}
/*
* Returns current client certificate issuer as one string
*
* This function returns issuer's distinguished name of the client
* certificate used in the current SSL connection, converting it into
* the current database encoding.
*
* Returns text datum.
*/
PG_FUNCTION_INFO_V1(ssl_issuer_dn);
Datum
ssl_issuer_dn(PG_FUNCTION_ARGS)
{
if (!(MyProcPort->peer))
PG_RETURN_NULL();
return X509_NAME_to_text(X509_get_issuer_name(MyProcPort->peer));
}
/*
* Returns information about available SSL extensions.
*
* Returns setof record made of the following values:
* - name of the extension.
* - value of the extension.
* - critical status of the extension.
*/
PG_FUNCTION_INFO_V1(ssl_extension_info);
Datum
ssl_extension_info(PG_FUNCTION_ARGS)
{
X509 *cert = MyProcPort->peer;
FuncCallContext *funcctx;
int call_cntr;
int max_calls;
MemoryContext oldcontext;
SSLExtensionInfoContext *fctx;
if (SRF_IS_FIRSTCALL())
{
TupleDesc tupdesc;
/* create a function context for cross-call persistence */
funcctx = SRF_FIRSTCALL_INIT();
/*
* Switch to memory context appropriate for multiple function calls
*/
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* Create a user function context for cross-call persistence */
fctx = (SSLExtensionInfoContext *) palloc(sizeof(SSLExtensionInfoContext));
/* Construct tuple descriptor */
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("function returning record called in context that cannot accept type record")));
fctx->tupdesc = BlessTupleDesc(tupdesc);
/* Set max_calls as a count of extensions in certificate */
max_calls = cert != NULL ? X509_get_ext_count(cert) : 0;
if (max_calls > 0)
{
/* got results, keep track of them */
funcctx->max_calls = max_calls;
funcctx->user_fctx = fctx;
}
else
{
/* fast track when no results */
MemoryContextSwitchTo(oldcontext);
SRF_RETURN_DONE(funcctx);
}
MemoryContextSwitchTo(oldcontext);
}
/* stuff done on every call of the function */
funcctx = SRF_PERCALL_SETUP();
/*
* Initialize per-call variables.
*/
call_cntr = funcctx->call_cntr;
max_calls = funcctx->max_calls;
fctx = funcctx->user_fctx;
/* do while there are more left to send */
if (call_cntr < max_calls)
{
Datum values[3];
bool nulls[3];
char *buf;
HeapTuple tuple;
Datum result;
BIO *membuf;
X509_EXTENSION *ext;
ASN1_OBJECT *obj;
int nid;
int len;
/* need a BIO for this */
membuf = BIO_new(BIO_s_mem());
if (membuf == NULL)
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("could not create OpenSSL BIO structure")));
/* Get the extension from the certificate */
ext = X509_get_ext(cert, call_cntr);
obj = X509_EXTENSION_get_object(ext);
/* Get the extension name */
nid = OBJ_obj2nid(obj);
if (nid == NID_undef)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("unknown OpenSSL extension in certificate at position %d",
call_cntr)));
values[0] = CStringGetTextDatum(OBJ_nid2sn(nid));
nulls[0] = false;
/* Get the extension value */
if (X509V3_EXT_print(membuf, ext, 0, 0) <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("could not print extension value in certificate at position %d",
call_cntr)));
len = BIO_get_mem_data(membuf, &buf);
values[1] = PointerGetDatum(cstring_to_text_with_len(buf, len));
nulls[1] = false;
/* Get critical status */
values[2] = BoolGetDatum(X509_EXTENSION_get_critical(ext));
nulls[2] = false;
/* Build tuple */
tuple = heap_form_tuple(fctx->tupdesc, values, nulls);
result = HeapTupleGetDatum(tuple);
if (BIO_free(membuf) != 1)
elog(ERROR, "could not free OpenSSL BIO structure");
SRF_RETURN_NEXT(funcctx, result);
}
/* All done */
SRF_RETURN_DONE(funcctx);
}
|