Thread: Use after free? in fe-connect.c:closePGconn
Hi=2C
Postgresql 9.5.3 32 bits
client 32bits libpq.dll with libpq.pdb
All calls of PQfinish is protected by:
if (conn !=3D NULL) {
PQfinish(conn)=3B
}
In [d:\pginstaller.auto\postgres.windows\src\interfaces\libpq\fe-connect.c=
=2C
closePGconn(PGconn *conn):
Does not check if conn is NULL.
Use after free?
Best regards=2C
Ranier
---------------------------------------------------------------------------=
-------------------------------------
Error #1: UNINITIALIZED READ: reading 0x0012fbb4-0x0012fbbb 7 byte(s) withi=
n 0x0012fb78-0x0012fbbb
# 0 system call NtCreateFile parameter #9
# 1 ntdll.dll!ZwCreateFile +0xb (0x7c90d09=
c <ntdll.dll+0xd09c>)
# 2 MSWSOCK.dll!? +0x0 (0x71a149c=
0 <MSWSOCK.dll+0x49c0>)
# 3 WS2_32.dll!WSASocketW +0x9c (0x71a740e=
b <WS2_32.dll+0x40eb>)
# 4 ngx_open_listening_sockets [c:\msys\1.0\nginx-=
1.10\src\core\ngx_connection.c:448]
# 5 ngx_init_cycle [c:\msys\1.0\nginx-=
1.10\src\core\ngx_cycle.c:609]
# 6 main [c:\msys\1.0\nginx-=
1.10\src\core\nginx.c:276]
Note: @0:00:03.954 in thread 3124
Error #2: UNADDRESSABLE ACCESS of freed memory: reading 0x020afd3c-0x020afd=
40 4 byte(s)
# 0 LIBPQ.dll!closePGconn [d:\pginstaller.auto\postgres.wi=
ndows\src\interfaces\libpq\fe-connect.c:2957]
# 1 LIBPQ.dll!PQfinish [d:\pginstaller.auto\postgres.wi=
ndows\src\interfaces\libpq\fe-connect.c:3055]
# 2 dbd_pgsql_close [c:\usr\src\dbd\postgresql\dbd_p=
gsql.c:279]
# 3 dbd_pgsql_cleanup [c:\usr\src\dbd\postgresql\dbd_p=
gsql.c:297]
# 4 ngx_destroy_pool [c:\msys\1.0\nginx-1.10\src\core=
\ngx_palloc.c:57]
# 5 ngx_master_process_exit [c:\msys\1.0\nginx-1.10\src\os\w=
in32\ngx_process_cycle.c:562]
# 6 ngx_master_process_cycle [c:\msys\1.0\nginx-1.10\src\os\w=
in32\ngx_process_cycle.c:235]
# 7 main [c:\msys\1.0\nginx-1.10\src\core=
\nginx.c:367]
Note: @8:39:35.860 in thread 3124
Note: prev lower malloc: 0x020afcf8-0x020afd08
Note: 0x020afd3c-0x020afd40 overlaps memory 0x020afd28-0x020b0d28 that was =
freed here:
Note: # 0 replace_free [d:\drmemory_package\commo=
n\alloc_replace.c:2706]
Note: # 1 ngx_hash_init [c:\msys\1.0\nginx-1.10\sr=
c\core\ngx_hash.c:426]
Note: # 2 ngx_http_merge_types [c:\msys\1.0\nginx-1.10\sr=
c\http\ngx_http.c:2089]
Note: # 3 ngx_http_gzip_merge_conf [c:\msys\1.0\nginx-1.10\sr=
c\http\modules\ngx_http_gzip_filter_module.c:1168]
Note: # 4 ngx_http_merge_servers [c:\msys\1.0\nginx-1.10\sr=
c\http\ngx_http.c:596]
Note: # 5 ngx_http_block [c:\msys\1.0\nginx-1.10\sr=
c\http\ngx_http.c:268]
Note: instruction: cmp 0x000000b4(%esi) $0xffffffff
Error #3: UNADDRESSABLE ACCESS beyond heap bounds: reading 0x020afd10-0x020=
afd14 4 byte(s)
# 0 LIBPQ.dll!closePGconn [d:\pginstaller.auto\postgres.wi=
ndows\src\interfaces\libpq\fe-connect.c:2957]
# 1 LIBPQ.dll!PQfinish [d:\pginstaller.auto\postgres.wi=
ndows\src\interfaces\libpq\fe-connect.c:3055]
# 2 dbd_pgsql_close [c:\usr\src\dbd\postgresql\dbd_p=
gsql.c:279]
# 3 dbd_pgsql_cleanup [c:\usr\src\dbd\postgresql\dbd_p=
gsql.c:297]
# 4 ngx_destroy_pool [c:\msys\1.0\nginx-1.10\src\core=
\ngx_palloc.c:57]
# 5 ngx_master_process_exit [c:\msys\1.0\nginx-1.10\src\os\w=
in32\ngx_process_cycle.c:562]
# 6 ngx_master_process_cycle [c:\msys\1.0\nginx-1.10\src\os\w=
in32\ngx_process_cycle.c:235]
# 7 main [c:\msys\1.0\nginx-1.10\src\core=
\nginx.c:367]
Note: @8:39:35.954 in thread 3124
Note: prev lower malloc: 0x020afcf8-0x020afd08
Note: instruction: cmp 0x00000088(%esi) $0x00000000
Error #4: UNADDRESSABLE ACCESS of freed memory: writing 0x020afd2b-0x020afd=
2c 1 byte(s)
# 0 LIBPQ.dll!closePGconn [d:\pginstaller.auto\postgres.wi=
ndows\src\interfaces\libpq\fe-connect.c:2974]
# 1 LIBPQ.dll!PQfinish [d:\pginstaller.auto\postgres.wi=
ndows\src\interfaces\libpq\fe-connect.c:3055]
# 2 dbd_pgsql_close [c:\usr\src\dbd\postgresql\dbd_p=
gsql.c:279]
# 3 dbd_pgsql_cleanup [c:\usr\src\dbd\postgresql\dbd_p=
gsql.c:297]
# 4 ngx_destroy_pool [c:\msys\1.0\nginx-1.10\src\core=
\ngx_palloc.c:57]
# 5 ngx_master_process_exit [c:\msys\1.0\nginx-1.10\src\os\w=
in32\ngx_process_cycle.c:562]
# 6 ngx_master_process_cycle [c:\msys\1.0\nginx-1.10\src\os\w=
in32\ngx_process_cycle.c:235]
# 7 main [c:\msys\1.0\nginx-1.10\src\core=
\nginx.c:367]
Note: @8:39:35.969 in thread 3124
Note: prev lower malloc: 0x020afcf8-0x020afd08
Note: 0x020afd2b-0x020afd2c overlaps memory 0x020afd28-0x020b0d28 that was =
freed here:
Note: # 0 replace_free [d:\drmemory_package\commo=
n\alloc_replace.c:2706]
Note: # 1 ngx_hash_init [c:\msys\1.0\nginx-1.10\sr=
c\core\ngx_hash.c:426]
Note: # 2 ngx_http_merge_types [c:\msys\1.0\nginx-1.10\sr=
c\http\ngx_http.c:2089]
Note: # 3 ngx_http_gzip_merge_conf [c:\msys\1.0\nginx-1.10\sr=
c\http\modules\ngx_http_gzip_filter_module.c:1168]
Note: # 4 ngx_http_merge_servers [c:\msys\1.0\nginx-1.10\sr=
c\http\ngx_http.c:596]
Note: # 5 ngx_http_block [c:\msys\1.0\nginx-1.10\sr=
c\http\ngx_http.c:268]
Note: instruction: mov $0x00 -> 0x000000a3(%esi)
---------------------------------------------------------------------------=
--------------------------------------------
=
Ranier VF <ranier_gyn@hotmail.com> writes:
> In [d:\pginstaller.auto\postgres.windows\src\interfaces\libpq\fe-connect.c,
> closePGconn(PGconn *conn):
> Does not check if conn is NULL.
All the callers do, so I don't entirely see your point.
The stack traces you show look to me like the fault is probably in
the caller, ie, calling PQfinish twice on the same "conn".
regards, tom lane
Hi Tom=2C
> All the callers do=2C so I don't entirely see your point.
Well=2C I still confuse...
> The stack traces you show look to me like the fault is probably in
> the caller=2C ie=2C calling PQfinish twice on the same "conn".
patch from dbd_pgsql_close function:
275 if (dbd->conn !=3D NULL) {
276 #if defined(DEBUG) && !defined(_WIN32)
277 PQuntrace(dbd->conn)=3B
278 #endif
279 PQfinish(dbd->conn)=3B
280 dbd->conn =3D NULL=3B
281 }
282 FREE(dbd)=3B
283 dbd =3D NULL=3B
IHMO=2C the caller of PQfinish can=B4t call twice.
Best regards=2C
Ranier
> From: tgl@sss.pgh.pa.us
> To: ranier_gyn@hotmail.com
> CC: pgsql-bugs@postgresql.org
> Subject: Re: [BUGS] Use after free? in fe-connect.c:closePGconn
> Date: Wed=2C 15 Jun 2016 19:05:53 -0400
>=20
> Ranier VF <ranier_gyn@hotmail.com> writes:
> > In [d:\pginstaller.auto\postgres.windows\src\interfaces\libpq\fe-conne=
ct.c=2C
> > closePGconn(PGconn *conn):
> > Does not check if conn is NULL.
>=20
> All the callers do=2C so I don't entirely see your point.
>=20
> The stack traces you show look to me like the fault is probably in
> the caller=2C ie=2C calling PQfinish twice on the same "conn".
>=20
> regards=2C tom lane
=20
=09
=20
Livre de v=EDrus. www.avast.com. =09
=09
=