8000 Distrust external OpenSSL clients; clear err queue · prmdeveloper/postgres@e3a493a · GitHub
[go: up one dir, main page]
Skip to content

Commit e3a493a

Browse files
peterepetere
committed 8000
Distrust external OpenSSL clients; clear err queue
OpenSSL has an unfortunate tendency to mix per-session state error handling with per-thread error handling. This can cause problems when programs that link to libpq with OpenSSL enabled have some other use of OpenSSL; without care, one caller of OpenSSL may cause problems for the other caller. Backend code might similarly be affected, for example when a third party extension independently uses OpenSSL without taking the appropriate precautions. To fix, don't trust other users of OpenSSL to clear the per-thread error queue. Instead, clear the entire per-thread queue ahead of certain I/O operations when it appears that there might be trouble (these I/O operations mostly need to call SSL_get_error() to check for success, which relies on the queue being empty). This is slightly aggressive, but it's pretty clear that the other callers have a very dubious claim to ownership of the per-thread queue. Do this is both frontend and backend code. Finally, be more careful about clearing our own error queue, so as to not cause these problems ourself. It's possibly that control previously did not always reach SSLerrmessage(), where ERR_get_error() was supposed to be called to clear the queue's earliest code. Make sure ERR_get_error() is always called, so as to spare other users of OpenSSL the possibility of similar problems caused by libpq (as opposed to problems caused by a third party OpenSSL library like PHP's OpenSSL extension). Again, do this is both frontend and backend code. See bug #12799 and https://bugs.php.net/bug.php?id=68276 Based on patches by Dave Vitek and Peter Eisentraut. From: Peter Geoghegan <pg@bowt.ie>
1 parent 11247dd commit e3a493a

File tree

2 files changed

+102
-44
lines changed

2 files changed

+102
-44
lines changed

‎src/backend/libpq/be-secure.c 8000

Lines changed: 48 additions & 20 deletions
Original file line numberDiff line numberDiff line change
@@ -86,7 +86,7 @@ static void info_cb(const SSL *ssl, int type, int args);
8686
static void initialize_SSL(void);
8787
static int open_server_SSL(Port *);
8888
static void close_SSL(Port *);
89-
static const char *SSLerrmessage(void);
89+
static const char *SSLerrmessage(unsigned long ecode);
9090
#endif
9191

9292
char *ssl_cert_file;
@@ -245,11 +245,14 @@ secure_read(Port *port, void *ptr, size_t len)
245245
if (port->ssl)
246246
{
247247
int err;
248+
unsigned long ecode;
248249

249250
rloop:
250251
errno = 0;
252+
ERR_clear_error();
251253
n = SSL_read(port->ssl, ptr, len);
252254
err = SSL_get_error(port->ssl, n);
255+
ecode = (err != SSL_ERROR_NONE || n < 0) ? ERR_get_error() : 0;
253256
switch (err)
254257
{
255258
case SSL_ERROR_NONE:
@@ -281,7 +284,7 @@ secure_read(Port *port, void *ptr, size_t len)
281284
case SSL_ERROR_SSL:
282285
ereport(COMMERROR,
283286
(errcode(ERRCODE_PROTOCOL_VIOLATION),
284-
errmsg("SSL error: %s", SSLerrmessage())));
287+
errmsg("SSL error: %s", SSLerrmessage(ecode))));
285288
/* fall through */
286289
case SSL_ERROR_ZERO_RETURN:
287290
errno = ECONNRESET;
@@ -321,6 +324,7 @@ secure_write(Port *port, void *ptr, size_t len)
3 8000 21324
if (port->ssl)
322325
{
323326
int err;
327+
unsigned long ecode;
324328

325329
if (ssl_renegotiation_limit && port->count > ssl_renegotiation_limit * 1024L)
326330
{
@@ -349,8 +353,10 @@ secure_write(Port *port, void *ptr, size_t len)
349353

350354
wloop:
351355
errno = 0;
356+
ERR_clear_error();
352357
n = SSL_write(port->ssl, ptr, len);
353358
err = SSL_get_error(port->ssl, n);
359+
ecode = (err != SSL_ERROR_NONE || n < 0) ? ERR_get_error() : 0;
354360
switch (err)
355361
{
356362
case SSL_ERROR_NONE:
@@ -376,7 +382,7 @@ secure_write(Port *port, void *ptr, size_t len)
376382
case SSL_ERROR_SSL:
377383
ereport(COMMERROR,
378384
(errcode(ERRCODE_PROTOCOL_VIOLATION),
379-
errmsg("SSL error: %s", SSLerrmessage())));
385+
errmsg("SSL error: %s", SSLerrmessage(ecode))));
380386
/* fall through */
381387
case SSL_ERROR_ZERO_RETURN:
382388
errno = ECONNRESET;
@@ -536,7 +542,8 @@ load_dh_file(int keylength)
536542
{
537543
if (DH_check(dh, &codes) == 0)
538544
{
539-
elog(LOG, "DH_check error (%s): %s", fnbuf, SSLerrmessage());
545+
elog(LOG, "DH_check error (%s): %s", fnbuf,
546+
SSLerrmessage(ERR_get_error()));
540547
return NULL;
541548
}
542549
if (codes & DH_CHECK_P_NOT_PRIME)
@@ -576,7 +583,7 @@ load_dh_buffer(const char *buffer, size_t len)
576583
if (dh == NULL)
577584
ereport(DEBUG2,
578585
(errmsg_internal("DH load buffer: %s",
579-
SSLerrmessage())));
586+
SSLerrmessage(ERR_get_error()))));
580587
BIO_free(bio);
581588

582589
return dh;
@@ -746,7 +753,7 @@ initialize_SSL(void)
746753
if (!SSL_context)
747754
ereport(FATAL,
748755
(errmsg("could not create SSL context: %s",
749-
SSLerrmessage())));
756+
SSLerrmessage(ERR_get_error()))));
750757

751758
/*
752759
* Disable OpenSSL's moving-write-buffer sanity check, because it
@@ -762,7 +769,7 @@ initialize_SSL(void)
762769
ereport(FATAL,
763770
(errcode(ERRCODE_CONFIG_FILE_ERROR),
764771
errmsg("could not load server certificate file \"%s\": %s",
765-
ssl_cert_file, SSLerrmessage())));
772+
ssl_cert_file, SSLerrmessage(ERR_get_error()))));
766773

767774
if (stat(ssl_key_file, &buf) != 0)
768775
ereport(FATAL,
@@ -792,12 +799,12 @@ initialize_SSL(void)
792799
SSL_FILETYPE_PEM) != 1)
793800
ereport(FATAL,
794801
(errmsg("could not load private key file \"%s\": %s",
795-
ssl_key_file, SSLerrmessage())));
802+
ssl_key_file, SSLerrmessage(ERR_get_error()))));
796803

797804
if (SSL_CTX_check_private_key(SSL_context) != 1)
798805
ereport(FATAL,
799806
(errmsg("check of private key failed: %s",
800-
SSLerrmessage())));
807+
SSLerrmessage(ERR_get_error()))));
801808
}
802809

803810
/* set up ephemeral DH keys, and disallow SSL v2 while at it */
@@ -817,7 +824,7 @@ initialize_SSL(void)
817824
(root_cert_list = SSL_load_client_CA_file(ssl_ca_file)) == NULL)
818825
ereport(FATAL,
819826
(errmsg("could not load root certificate file \"%s\": %s",
820-
ssl_ca_file, SSLerrmessage())));
827+
ssl_ca_file, SSLerrmessage(ERR_get_error()))));
821828
}
822829

823830
/*----------
@@ -848,7 +855,7 @@ initialize_SSL(void)
848855
else
849856
ereport(FATAL,
850857
(errmsg("could not load SSL certificate revocation list file \"%s\": %s",
851-
ssl_crl_file, SSLerrmessage())));
858+
ssl_crl_file, SSLerrmessage(ERR_get_error()))));
852859
}
853860
}
854861

@@ -884,6 +891,7 @@ open_server_SSL(Port *port)
884891
{
885892
int r;
886893
int err;
894+
unsigned long ecode;
887895

888896
Assert(!port->ssl);
889897
Assert(!port->peer);
@@ -893,23 +901,43 @@ open_server_SSL(Port *port)
893901
ereport(COMMERROR,
894902
(errcode(ERRCODE_PROTOCOL_VIOLATION),
895903
errmsg("could not initialize SSL connection: %s",
896-
SSLerrmessage())));
904+
SSLerrmessage(ERR_get_error()))));
897905
return -1;
898906
}
899907
if (!my_SSL_set_fd(port->ssl, port->sock))
900908
{
901909
ereport(COMMERROR,
902910
(errcode(ERRCODE_PROTOCOL_VIOLATION),
903911
errmsg("could not set SSL socket: %s",
904-
SSLerrmessage())));
912+
SSLerrmessage(ERR_get_error()))));
905913
return -1;
906914
}
907915

908916
aloop:
917+
/*
918+
* Prepare to call SSL_get_error() by clearing thread's OpenSSL error
919+
* queue. In general, the current thread's error queue must be empty
920+
* before the TLS/SSL I/O operation is attempted, or SSL_get_error()
921+
* will not work reliably. An extension may have failed to clear the
922+
* per-thread error queue following another call to an OpenSSL I/O
923+
* routine.
924+
*/
925+
ERR_clear_error();
909926
r = SSL_accept(port->ssl);
910927
if (r <= 0)
911928
{
912929
err = SSL_get_error(port->ssl, r);
930+
931+
/*
932+
* Other clients of OpenSSL in the backend may fail to call
933+
* ERR_get_error(), but we always do, so as to not cause problems
934+
* for OpenSSL clients that don't call ERR_clear_error()
935+
* defensively. Be sure that this happens by calling now.
936+
* SSL_get_error() relies on the OpenSSL per-thread error queue
937+
* being intact, so this is the earliest possible point
938+
* ERR_get_error() may be called.
939+
*/
940+
ecode = ERR_get_error();
913941
switch (err)
914942
{
915943
case SSL_ERROR_WANT_READ:
@@ -935,7 +963,7 @@ open_server_SSL(Port *port)
935963
ereport(COMMERROR,
936964
(errcode(ERRCODE_PROTOCOL_VIOLATION),
937965
errmsg("could not accept SSL connection: %s",
938-
SSLerrmessage())));
966+
SSLerrmessage(ecode))));
939967
break;
940968
case SSL_ERROR_ZERO_RETURN:
941969
ereport(COMMERROR,
@@ -1036,24 +1064,24 @@ close_SSL(Port *port)
10361064
/*
10371065
* Obtain reason string for last SSL error
10381066
*
1067+
* ERR_get_error() is used by caller to get errcode to pass here.
1068+
*
10391069
* Some caution is needed here since ERR_reason_error_string will
10401070
* return NULL if it doesn't recognize the error code. We don't
10411071
* want to return NULL ever.
10421072
*/
10431073
static const char *
1044-
SSLerrmessage(void)
1074+
SSLerrmessage(unsigned long ecode)
10451075
{
1046-
unsigned long errcode;
10471076
const char *errreason;
10481077
static char errbuf[32];
10491078

1050-
errcode = ERR_get_error();
1051-
if (errcode == 0)
1079+
if (ecode == 0)
10521080
return _("no SSL error reported");
1053-
errreason = ERR_reason_error_string(errcode);
1081+
errreason = ERR_reason_error_string(ecode);
10541082
if (errreason != NULL)
10551083
return errreason;
1056-
snprintf(errbuf, sizeof(errbuf), _("SSL error code %lu"), errcode);
1084+
snprintf(errbuf, sizeof(errbuf), _("SSL error code %lu"), ecode);
10571085
return errbuf;
10581086
}
10591087

0 commit comments

Comments
 (0)
0