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alvherrealvherre
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Add conninfo to pg_stat_wal_receiver
Commit b1a9bad introduced a stats view to provide insight into the running WAL receiver, but neglected to include the connection string in it, as reported by Michaël Paquier. This commit fixes that omission. (Any security-sensitive information is not disclosed). While at it, close the mild security hole that we were exposing the password in the connection string in shared memory. This isn't user-accessible, but it still looks like a good idea to avoid having the cleartext password in memory. Author: Michaël Paquier, Álvaro Herrera Review by: Vik Fearing Discussion: https://www.postgresql.org/message-id/CAB7nPqStg4M561obo7ryZ5G+fUydG4v1Ajs1xZT1ujtu+woRag@mail.gmail.com
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7 files changed

+122
-39
lines changed

7 files changed

+122
-39
lines changed

‎doc/src/sgml/monitoring.sgml

Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1302,6 +1302,14 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
13021302
<entry><type>text</></entry>
13031303
<entry>Replication slot name used by this WAL receiver</entry>
13041304
</row>
1305+
<row>
1306+
<entry><structfield>conn_info</></entry>
1307+
<entry><type>text</></entry>
1308+
<entry>
1309+
Connection string used by this WAL receiver,
1310+
with security-sensitive fields obfuscated.
1311+
</entry>
1312+
</row>
13051313
</tbody>
13061314
</tgroup>
13071315
</table>

‎src/backend/catalog/system_views.sql

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -681,7 +681,8 @@ CREATE VIEW pg_stat_wal_receiver AS
681681
s.last_msg_receipt_time,
682682
s.latest_end_lsn,
683683
s.latest_end_time,
684-
s.slot_name
684+
s.slot_name,
685+
s.conn_info
685686
FROM pg_stat_get_wal_receiver() s
686687
WHERE s.pid IS NOT NULL;
687688

‎src/backend/replication/libpqwalreceiver/libpqwalreceiver.c

Lines changed: 52 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -20,6 +20,7 @@
2020
#include <sys/time.h>
2121

2222
#include "libpq-fe.h"
23+
#include "pqexpbuffer.h"
2324
#include "access/xlog.h"
2425
#include "miscadmin.h"
2526
#include "replication/walreceiver.h"
@@ -47,6 +48,7 @@ static char *recvBuf = NULL;
4748

4849
/* Prototypes for interface functions */
4950
static void libpqrcv_connect(char *conninfo);
51+
static char *libpqrcv_get_conninfo(void);
5052
static void libpqrcv_identify_system(TimeLineID *primary_tli);
5153
static void libpqrcv_readtimelinehistoryfile(TimeLineID tli, char **filename, char **content, int *len);
5254
static bool libpqrcv_startstreaming(TimeLineID tli, XLogRecPtr startpoint,
@@ -74,6 +76,7 @@ _PG_init(void)
7476
walrcv_disconnect != NULL)
7577
elog(ERROR, "libpqwalreceiver already loaded");
7678
walrcv_connect = libpqrcv_connect;
79+
walrcv_get_conninfo = libpqrcv_get_conninfo;
7780
walrcv_identify_system = libpqrcv_identify_system;
7881
walrcv_readtimelinehistoryfile = libpqrcv_readtimelinehistoryfile;
7982
walrcv_startstreaming = libpqrcv_startstreaming;
@@ -117,6 +120,55 @@ libpqrcv_connect(char *conninfo)
117120
PQerrorMessage(streamConn))));
118121
}
119122

123+
/*
124+
* Return a user-displayable conninfo string. Any security-sensitive fields
125+
* are obfuscated.
126+
*/
127+
static char *
128+
libpqrcv_get_conninfo(void)
129+
{
130+
PQconninfoOption *conn_opts;
131+
PQconninfoOption *conn_opt;
132+
PQExpBufferData buf;
133+
char *retval;
134+
135+
Assert(streamConn != NULL);
136+
137+
initPQExpBuffer(&buf);
138+
conn_opts = PQconninfo(streamConn);
139+
140+
if (conn_opts == NULL)
141+
ereport(ERROR,
142+
(errmsg("could not parse connection string: %s",
143+
_("out of memory"))));
144+
145+
/* build a clean connection string from pieces */
146+
for (conn_opt = conn_opts; conn_opt->keyword != NULL; conn_opt++)
147+
{
148+
bool obfuscate;
149+
150+
/* Skip debug and empty options */
151+
if (strchr(conn_opt->dispchar, 'D') ||
152+
conn_opt->val == NULL ||
153+
conn_opt->val[0] == '\0')
154+
continue;
155+
156+
/* Obfuscate security-sensitive options */
157+
obfuscate = strchr(conn_opt->dispchar, '*') != NULL;
158+
159+
appendPQExpBuffer(&buf, "%s%s=%s",
160+
buf.len == 0 ? "" : " ",
161+
conn_opt->keyword,
162+
obfuscate ? "********" : conn_opt->val);
163+
}
164+
165+
PQconninfoFree(conn_opts);
166+
167+
retval = PQExpBufferDataBroken(buf) ? NULL : pstrdup(buf.data);
168+
termPQExpBuffer(&buf);
169+
return retval;
170+
}
171+
120172
/*
121173
* Check that primary's system identifier matches ours, and fetch the current
122174
* timeline ID of the primary.

‎src/backend/replication/walreceiver.c

Lines changed: 50 additions & 35 deletions
Original file line numberDiff line numberDiff line change
@@ -75,6 +75,7 @@ bool hot_standby_feedback;
7575

7676
/* libpqreceiver hooks to these when loaded */
7777
walrcv_connect_type walrcv_connect = NULL;
78+
walrcv_get_conninfo_type walrcv_get_conninfo = NULL;
7879
walrcv_identify_system_type walrcv_identify_system = NULL;
7980
walrcv_startstreaming_type walrcv_startstreaming = NULL;
8081
walrcv_endstreaming_type walrcv_endstreaming = NULL;
@@ -192,6 +193,7 @@ void
192193
WalReceiverMain(void)
193194
{
194195
char conninfo[MAXCONNINFO];
196+
char *tmp_conninfo;
195197
char slotname[NAMEDATALEN];
196198
XLogRecPtr startpoint;
197199
TimeLineID startpointTLI;
@@ -282,7 +284,9 @@ WalReceiverMain(void)
282284

283285
/* Load the libpq-specific functions */
284286
load_file("libpqwalreceiver", false);
285-
if (walrcv_connect == NULL || walrcv_startstreaming == NULL ||
287+
if (walrcv_connect == NULL ||
288+
walrcv_get_conninfo == NULL ||
289+
walrcv_startstreaming == NULL ||
286290
walrcv_endstreaming == NULL ||
287291
walrcv_identify_system == NULL ||
288292
walrcv_readtimelinehistoryfile == NULL ||
@@ -304,6 +308,21 @@ WalReceiverMain(void)
304308
walrcv_connect(conninfo);
305309
DisableWalRcvImmediateExit();
306310

311+
/*
312+
* Save user-visible connection string. This clobbers the original
313+
* conninfo, for security.
314+
*/
315+
tmp_conninfo = walrcv_get_conninfo();
316+
SpinLockAcquire(&walrcv->mutex);
317+
memset(walrcv->conninfo, 0, MAXCONNINFO);
318+
if (tmp_conninfo)
319+
{
320+
strlcpy((char *) walrcv->conninfo, tmp_conninfo, MAXCONNINFO);
321+
pfree(tmp_conninfo);
322+
}
323+
walrcv->ready_to_display = true;
324+
SpinLockRelease(&walrcv->mutex);
325+
307326
first_stream = true;
308327
for (;;)
309328
{
@@ -1308,10 +1327,9 @@ WalRcvGetStateString(WalRcvState state)
13081327
Datum
13091328
pg_stat_get_wal_receiver(PG_FUNCTION_ARGS)
13101329
{
1311-
#define PG_STAT_GET_WAL_RECEIVER_COLS 11
13121330
TupleDesc tupdesc;
1313-
Datum values[PG_STAT_GET_WAL_RECEIVER_COLS];
1314-
bool nulls[PG_STAT_GET_WAL_RECEIVER_COLS];
1331+
Datum *values;
1332+
bool *nulls;
13151333
WalRcvData *walrcv = WalRcv;
13161334
WalRcvState state;
13171335
XLogRecPtr receive_start_lsn;
@@ -1323,41 +1341,33 @@ pg_stat_get_wal_receiver(PG_FUNCTION_ARGS)
13231341
XLogRecPtr latest_end_lsn;
13241342
TimestampTz latest_end_time;
13251343
char *slotname;
1344+
char *conninfo;
13261345

13271346
/* No WAL receiver, just return a tuple with NULL values */
13281347
if (walrcv->pid == 0)
13291348
PG_RETURN_NULL();
13301349

1331-
/* Initialise values and NULL flags arrays */
1332-
MemSet(values, 0, sizeof(values));
1333-
MemSet(nulls, 0, sizeof(nulls));
1334-
1335-
/* Initialise attributes information in the tuple descriptor */
1336-
tupdesc = CreateTemplateTupleDesc(PG_STAT_GET_WAL_RECEIVER_COLS, false);
1337-
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "pid",
1338-
INT4OID, -1, 0);
1339-
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "status",
1340-
TEXTOID, -1, 0);
1341-
TupleDescInitEntry(tupdesc, (AttrNumber) 3, "receive_start_lsn",
1342-
LSNOID, -1, 0);
1343-
TupleDescInitEntry(tupdesc, (AttrNumber) 4, "receive_start_tli",
1344-
INT4OID, -1, 0);
1345-
TupleDescInitEntry(tupdesc, (AttrNumber) 5, "received_lsn",
1346-
LSNOID, -1, 0);
1347-
TupleDescInitEntry(tupdesc, (AttrNumber) 6, "received_tli",
1348-
INT4OID, -1, 0);
1349-
TupleDescInitEntry(tupdesc, (AttrNumber) 7, "last_msg_send_time",
1350-
TIMESTAMPTZOID, -1, 0);
1351-
TupleDescInitEntry(tupdesc, (AttrNumber) 8, "last_msg_receipt_time",
1352-
TIMESTAMPTZOID, -1, 0);
1353-
TupleDescInitEntry(tupdesc, (AttrNumber) 9, "latest_end_lsn",
1354-
LSNOID, -1, 0);
1355-
TupleDescInitEntry(tupdesc, (AttrNumber) 10, "latest_end_time",
1356-
TIMESTAMPTZOID, -1, 0);
1357-
TupleDescInitEntry(tupdesc, (AttrNumber) 11, "slot_name",
1358-
TEXTOID, -1, 0);
1359-
1360-
BlessTupleDesc(tupdesc);
1350+
/*
1351+
* Users attempting to read this data mustn't be shown security sensitive
1352+
* data, so sleep until everything has been properly obfuscated.
1353+
*/
1354+
retry:
1355+
SpinLockAcquire(&walrcv->mutex);
1356+
if (!walrcv->ready_to_display)
1357+
{
1358+
SpinLockRelease(&walrcv->mutex);
1359+
CHECK_FOR_INTERRUPTS();
1360+
pg_usleep(1000);
1361+
goto retry;
1362+
}
1363+
SpinLockRelease(&walrcv->mutex);
1364+
1365+
/* determine result type */
1366+
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
1367+
elog(ERROR, "return type must be a row type");
1368+
1369+
values = palloc0(sizeof(Datum) * tupdesc->natts);
1370+
nulls = palloc0(sizeof(bool) * tupdesc->natts);
13611371

13621372
/* Take a lock to ensure value consistency */
13631373
SpinLockAcquire(&walrcv->mutex);
@@ -1371,6 +1381,7 @@ pg_stat_get_wal_receiver(PG_FUNCTION_ARGS)
13711381
latest_end_lsn = walrcv->latestWalEnd;
13721382
latest_end_time = walrcv->latestWalEndTime;
13731383
slotname = pstrdup(walrcv->slotname);
1384+
conninfo = pstrdup(walrcv->conninfo);
13741385
SpinLockRelease(&walrcv->mutex);
13751386

13761387
/* Fetch values */
@@ -1382,7 +1393,7 @@ pg_stat_get_wal_receiver(PG_FUNCTION_ARGS)
13821393
* Only superusers can see details. Other users only get the pid value
13831394
* to know whether it is a WAL receiver, but no details.
13841395
*/
1385-
MemSet(&nulls[1], true, PG_STAT_GET_WAL_RECEIVER_COLS - 1);
1396+
MemSet(&nulls[1], true, sizeof(bool) * (tupdesc->natts - 1));
13861397
}
13871398
else
13881399
{
@@ -1418,6 +1429,10 @@ pg_stat_get_wal_receiver(PG_FUNCTION_ARGS)
14181429
nulls[10] = true;
14191430
else
14201431
values[10] = CStringGetTextDatum(slotname);
1432+
if (*conninfo == '\0')
1433+
nulls[11] = true;
1434+
else
1435+
values[11] = CStringGetTextDatum(conninfo);
14211436
}
14221437

14231438
/* Returns the record as Datum */

‎src/include/catalog/catversion.h

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -53,6 +53,6 @@
5353
*/
5454

5555
/* yyyymmddN */
56-
#define CATALOG_VERSION_NO 201606261
56+
#define CATALOG_VERSION_NO 201606291
5757

5858
#endif

‎src/include/catalog/pg_proc.h

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2746,7 +2746,7 @@ DATA(insert OID = 3318 ( pg_stat_get_progress_info PGNSP PGUID 12 1 100 0 0
27462746
DESCR("statistics: information about progress of backends running maintenance command");
27472747
DATA(insert OID = 3099 ( pg_stat_get_wal_senders PGNSP PGUID 12 1 10 0 0 f f f f f t s r 0 0 2249 "" "{23,25,3220,3220,3220,3220,23,25}" "{o,o,o,o,o,o,o,o}" "{pid,state,sent_location,write_location,flush_location,replay_location,sync_priority,sync_state}" _null_ _null_ pg_stat_get_wal_senders _null_ _null_ _null_ ));
27482748
DESCR("statistics: information about currently active replication");
2749-
DATA(insert OID = 3317 ( pg_stat_get_wal_receiver PGNSP PGUID 12 1 0 0 0 f f f f f f s r 0 0 2249 "" "{23,25,3220,23,3220,23,1184,1184,3220,1184,25}" "{o,o,o,o,o,o,o,o,o,o,o}" "{pid,status,receive_start_lsn,receive_start_tli,received_lsn,received_tli,last_msg_send_time,last_msg_receipt_time,latest_end_lsn,latest_end_time,slot_name}" _null_ _null_ pg_stat_get_wal_receiver _null_ _null_ _null_ ));
2749+
DATA(insert OID = 3317 ( pg_stat_get_wal_receiver PGNSP PGUID 12 1 0 0 0 f f f f f f s r 0 0 2249 "" "{23,25,3220,23,3220,23,1184,1184,3220,1184,25,25}" "{o,o,o,o,o,o,o,o,o,o,o,o}" "{pid,status,receive_start_lsn,receive_start_tli,received_lsn,received_tli,last_msg_send_time,last_msg_receipt_time,latest_end_lsn,latest_end_time,slot_name,conn_info}" _null_ _null_ pg_stat_get_wal_receiver _null_ _null_ _null_ ));
27502750
DESCR("statistics: information about WAL receiver");
27512751
DATA(insert OID = 2026 ( pg_backend_pid PGNSP PGUID 12 1 0 0 0 f f f f t f s r 0 0 23 "" _null_ _null_ _null_ _null_ _null_ pg_backend_pid _null_ _null_ _null_ ));
27522752
DESCR("statistics: current backend PID");

‎src/include/replication/walreceiver.h

Lines changed: 8 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -100,7 +100,8 @@ typedef struct
100100
TimestampTz latestWalEndTime;
101101

102102
/*
103-
* connection string; is used for walreceiver to connect with the primary.
103+
* connection string; initially set to connect to the primary, and later
104+
* clobbered to hide security-sensitive fields.
104105
*/
105106
char conninfo[MAXCONNINFO];
106107

@@ -118,6 +119,9 @@ typedef struct
118119
*/
119120
bool force_reply;
120121

122+
/* set true once conninfo is ready to display (obfuscated pwds etc) */
123+
bool ready_to_display;
124+
121125
/*
122126
* Latch used by startup process to wake up walreceiver after telling it
123127
* where to start streaming (after setting receiveStart and
@@ -133,6 +137,9 @@ extern WalRcvData *WalRcv;
133137
typedef void (*walrcv_connect_type) (char *conninfo);
134138
extern PGDLLIMPORT walrcv_connect_type walrcv_connect;
135139

140+
typedef char *(*walrcv_get_conninfo_type) (void);
141+
extern PGDLLIMPORT walrcv_get_conninfo_type walrcv_get_conninfo;
142+
136143
typedef void (*walrcv_identify_system_type) (TimeLineID *primary_tli);
137144
extern PGDLLIMPORT walrcv_identify_system_type walrcv_identify_system;
138145

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