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hlinnakahlinnaka
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Revert "Replace PostmasterRandom() with a stronger way of generating randomness."
This reverts commit 9e083fd. That was a few bricks shy of a load: * Query cancel stopped working * Buildfarm member pademelon stopped working, because the box doesn't have /dev/urandom nor /dev/random. This clearly needs some more discussion, and a quite different patch, so revert for now.
1 parent 7d3235b commit faae1c9

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9 files changed

+384
-244
lines changed

9 files changed

+384
-244
lines changed

‎contrib/pgcrypto/Makefile

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,7 @@
11
# contrib/pgcrypto/Makefile
22

33
INT_SRCS = md5.c sha1.c sha2.c internal.c internal-sha2.c blf.c rijndael.c \
4-
fortuna.c pgp-mpi-internal.c imath.c
4+
fortuna.c random.c pgp-mpi-internal.c imath.c
55
INT_TESTS = sha2
66

77
OSSL_SRCS = openssl.c pgp-mpi-openssl.c

‎contrib/pgcrypto/internal.c

Lines changed: 16 additions & 24 deletions
Original file line numberDiff line numberDiff line change
@@ -626,6 +626,8 @@ static time_t check_time = 0;
626626
static void
627627
system_reseed(void)
628628
{
629+
uint8 buf[1024];
630+
int n;
629631
time_t t;
630632
int skip = 1;
631633

@@ -640,34 +642,24 @@ system_reseed(void)
640642
else if (check_time == 0 ||
641643
(t - check_time) > SYSTEM_RESEED_CHECK_TIME)
642644
{
643-
uint8 buf;
644-
645645
check_time = t;
646646

647647
/* roll dice */
648-
px_get_random_bytes(&buf, 1);
649-
skip = (buf >= SYSTEM_RESEED_CHANCE);
650-
651-
/* clear 1 byte */
652-
px_memset(&buf, 0, sizeof(buf));
653-
}
654-
if (!skip)
655-
{
656-
/*
657-
* fortuna_add_entropy passes the input to SHA-256, so there's no
658-
* point in giving it more than 256 bits of input to begin with.
659-
*/
660-
uint8 buf[32];
661-
662-
if (!pg_strong_random(buf, sizeof(buf)))
663-
ereport(ERROR,
664-
(errcode(ERRCODE_INTERNAL_ERROR),
665-
errmsg("could not acquire random data")));
666-
fortuna_add_entropy(buf, sizeof(buf));
667-
668-
seed_time = t;
669-
px_memset(buf, 0, sizeof(buf));
648+
px_get_random_bytes(buf, 1);
649+
skip = buf[0] >= SYSTEM_RESEED_CHANCE;
670650
}
651+
/* clear 1 byte */
652+
px_memset(buf, 0, sizeof(buf));
653+
654+
if (skip)
655+
return;
656+
657+
n = px_acquire_system_randomness(buf);
658+
if (n > 0)
659+
fortuna_add_entropy(buf, n);
660+
661+
seed_time = t;
662+
px_memset(buf, 0, sizeof(buf));
671663
}
672664

673665
int

‎contrib/pgcrypto/random.c

Lines changed: 247 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,247 @@
1+
/*
2+
* random.c
3+
* Acquire randomness from system. For seeding RNG.
4+
*
5+
* Copyright (c) 2001 Marko Kreen
6+
* All rights reserved.
7+
*
8+
* Redistribution and use in source and binary forms, with or without
9+
* modification, are permitted provided that the following conditions
10+
* are met:
11+
* 1. Redistributions of source code must retain the above copyright
12+
* notice, this list of conditions and the following disclaimer.
13+
* 2. Redistributions in binary form must reproduce the above copyright
14+
* notice, this list of conditions and the following disclaimer in the
15+
* documentation and/or other materials provided with the distribution.
16+
*
17+
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18+
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19+
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20+
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21+
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22+
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23+
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24+
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25+
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26+
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27+
* SUCH DAMAGE.
28+
*
29+
* contrib/pgcrypto/random.c
30+
*/
31+
32+
#include "postgres.h"
33+
34+
#include "px.h"
35+
#include "utils/memdebug.h"
36+
37+
/* how many bytes to ask from system random provider */
38+
#define RND_BYTES 32
39+
40+
/*
41+
* Try to read from /dev/urandom or /dev/random on these OS'es.
42+
*
43+
* The list can be pretty liberal, as the device not existing
44+
* is expected event.
45+
*/
46+
#if defined(__linux__) || defined(__FreeBSD__) || defined(__OpenBSD__) \
47+
|| defined(__NetBSD__) || defined(__DragonFly__) \
48+
|| defined(__darwin__) || defined(__SOLARIS__) \
49+
|| defined(__hpux) || defined(__HPUX__) \
50+
|| defined(__CYGWIN__) || defined(_AIX)
51+
52+
#define TRY_DEV_RANDOM
53+
54+
#include <fcntl.h>
55+
#include <unistd.h>
56+
57+
static int
58+
safe_read(int fd, void *buf, size_t count)
59+
{
60+
int done = 0;
61+
char *p = buf;
62+
int res;
63+
64+
while (count)
65+
{
66+
res = read(fd, p, count);
67+
if (res <= 0)
68+
{
69+
if (errno == EINTR)
70+
continue;
71+
return PXE_DEV_READ_ERROR;
72+
}
73+
p += res;
74+
done += res;
75+
count -= res;
76+
}
77+
return done;
78+
}
79+
80+
static uint8 *
81+
try_dev_random(uint8 *dst)
82+
{
83+
int fd;
84+
int res;
85+
86+
fd = open("/dev/urandom", O_RDONLY, 0);
87+
if (fd == -1)
88+
{
89+
fd = open("/dev/random", O_RDONLY, 0);
90+
if (fd == -1)
91+
return dst;
92+
}
93+
res = safe_read(fd, dst, RND_BYTES);
94+
close(fd);
95+
if (res > 0)
96+
dst += res;
97+
return dst;
98+
}
99+
#endif
100+
101+
/*
102+
* Try to find randomness on Windows
103+
*/
104+
#ifdef WIN32
105+
106+
#define TRY_WIN32_GENRAND
107+
#define TRY_WIN32_PERFC
108+
109+
#include <windows.h>
110+
#include <wincrypt.h>
111+
112+
/*
113+
* this function is from libtomcrypt
114+
*
115+
* try to use Microsoft crypto API
116+
*/
117+
static uint8 *
118+
try_win32_genrand(uint8 *dst)
119+
{
120+
int res;
121+
HCRYPTPROV h = 0;
122+
123+
res = CryptAcquireContext(&h, NULL, MS_DEF_PROV, PROV_RSA_FULL,
124+
(CRYPT_VERIFYCONTEXT | CRYPT_MACHINE_KEYSET));
125+
if (!res)
126+
res = CryptAcquireContext(&h, NULL, MS_DEF_PROV, PROV_RSA_FULL,
127+
CRYPT_VERIFYCONTEXT | CRYPT_MACHINE_KEYSET | CRYPT_NEWKEYSET);
128+
if (!res)
129+
return dst;
130+
131+
res = CryptGenRandom(h, RND_BYTES, dst);
132+
if (res == TRUE)
133+
dst += RND_BYTES;
134+
135+
CryptReleaseContext(h, 0);
136+
return dst;
137+
}
138+
139+
static uint8 *
140+
try_win32_perfc(uint8 *dst)
141+
{
142+
int res;
143+
LARGE_INTEGER time;
144+
145+
res = QueryPerformanceCounter(&time);
146+
if (!res)
147+
return dst;
148+
149+
memcpy(dst, &time, sizeof(time));
150+
return dst + sizeof(time);
151+
}
152+
#endif /* WIN32 */
153+
154+
155+
/*
156+
* If we are not on Windows, then hopefully we are
157+
* on a unix-like system. Use the usual suspects
158+
* for randomness.
159+
*/
160+
#ifndef WIN32
161+
162+
#define TRY_UNIXSTD
163+
164+
#include <sys/types.h>
165+
#include <sys/time.h>
166+
#include <time.h>
167+
#include <unistd.h>
168+
169+
/*
170+
* Everything here is predictible, only needs some patience.
171+
*
172+
* But there is a chance that the system-specific functions
173+
* did not work. So keep faith and try to slow the attacker down.
174+
*/
175+
static uint8 *
176+
try_unix_std(uint8 *dst)
177+
{
178+
pid_t pid;
179+
int x;
180+
PX_MD *md;
181+
struct timeval tv;
182+
int res;
183+
184+
/* process id */
185+
pid = getpid();
186+
memcpy(dst, (uint8 *) &pid, sizeof(pid));
187+
dst += sizeof(pid);
188+
189+
/* time */
190+
gettimeofday(&tv, NULL);
191+
memcpy(dst, (uint8 *) &tv, sizeof(tv));
192+
dst += sizeof(tv);
193+
194+
/* pointless, but should not hurt */
195+
x = random();
196+
memcpy(dst, (uint8 *) &x, sizeof(x));
197+
dst += sizeof(x);
198+
199+
/* hash of uninitialized stack and heap allocations */
200+
res = px_find_digest("sha1", &md);
201+
if (res >= 0)
202+
{
203+
uint8 *ptr;
204+
uint8 stack[8192];
205+
int alloc = 32 * 1024;
206+
207+
VALGRIND_MAKE_MEM_DEFINED(stack, sizeof(stack));
208+
px_md_update(md, stack, sizeof(stack));
209+
ptr = px_alloc(alloc);
210+
VALGRIND_MAKE_MEM_DEFINED(ptr, alloc);
211+
px_md_update(md, ptr, alloc);
212+
px_free(ptr);
213+
214+
px_md_finish(md, dst);
215+
px_md_free(md);
216+
217+
dst += 20;
218+
}
219+
220+
return dst;
221+
}
222+
#endif
223+
224+
/*
225+
* try to extract some randomness for initial seeding
226+
*
227+
* dst should have room for 1024 bytes.
228+
*/
229+
unsigned
230+
px_acquire_system_randomness(uint8 *dst)
231+
{
232+
uint8 *p = dst;
233+
234+
#ifdef TRY_DEV_RANDOM
235+
p = try_dev_random(p);
236+
#endif
237+
#ifdef TRY_WIN32_GENRAND
238+
p = try_win32_genrand(p);
239+
#endif
240+
#ifdef TRY_WIN32_PERFC
241+
p = try_win32_perfc(p);
242+
#endif
243+
#ifdef TRY_UNIXSTD
244+
p = try_unix_std(p);
245+
#endif
246+
return p - dst;
247+
}

‎src/backend/libpq/auth.c

Lines changed: 4 additions & 23 deletions
Original file line numberDiff line numberDiff line change
@@ -45,12 +45,6 @@ static void auth_failed(Port *port, int status, char *logdetail);
4545
static char *recv_password_packet(Port *port);
4646
static int recv_and_check_password_packet(Port *port, char **logdetail);
4747

48-
/*----------------------------------------------------------------
49-
* MD5 authentication
50-
*----------------------------------------------------------------
51-
*/
52-
static int CheckMD5Auth(Port *port, char **logdetail);
53-
5448

5549
/*----------------------------------------------------------------
5650
* Ident authentication
@@ -541,7 +535,9 @@ ClientAuthentication(Port *port)
541535
ereport(FATAL,
542536
(errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
543537
errmsg("MD5 authentication is not supported when \"db_user_namespace\" is enabled")));
544-
status = CheckMD5Auth(port, &logdetail);
538+
/* include the salt to use for computing the response */
539+
sendAuthRequest(port, AUTH_REQ_MD5, port->md5Salt, 4);
540+
status = recv_and_check_password_packet(port, &logdetail);
545541
break;
546542

547543
case uaPassword:
@@ -696,25 +692,10 @@ recv_password_packet(Port *port)
696692

697693

698694
/*----------------------------------------------------------------
699-
* MD5 and password authentication
695+
* MD5 authentication
700696
*----------------------------------------------------------------
701697
*/
702698

703-
static int
704-
CheckMD5Auth(Port *port, char **logdetail)
705-
{
706-
/* include the salt to use for computing the response */
707-
if (!pg_strong_random(port->md5Salt, sizeof(port->md5Salt)))
708-
{
709-
*logdetail = psprintf(_("Could not generate random salt"));
710-
return STATUS_ERROR;
711-
}
712-
713-
sendAuthRequest(port, AUTH_REQ_MD5, port->md5Salt, 4);
714-
return recv_and_check_password_packet(port, logdetail);
715-
}
716-
717-
718699
/*
719700
* Called when we have sent an authorization request for a password.
720701
* Get the response and check it.

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