8000 Secure Unix-domain sockets of "make check" temporary clusters. · larkly/postgres-docker@481831b · GitHub
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Secure Unix-domain sockets of "make check" temporary clusters.
Any OS user able to access the socket can connect as the bootstrap superuser and proceed to execute arbitrary code as the OS user running the test. Protect against that by placing the socket in a temporary, mode-0700 subdirectory of /tmp. The pg_regress-based test suites and the pg_upgrade test suite were vulnerable; the $(prove_check)-based test suites were already secure. Back-patch to 8.4 (all supported versions). The hazard remains wherever the temporary cluster accepts TCP connections, notably on Windows. As a convenient side effect, this lets testing proceed smoothly in builds that override DEFAULT_PGSOCKET_DIR. Popular non-default values like /var/run/postgresql are often unwritable to the build user. Security: CVE-2014-0067
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‎doc/src/sgml/regress.sgml

Lines changed: 8 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -58,21 +58,14 @@ gmake check
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<warning>
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<para>
61-
This test method starts a temporary server, which is configured to accept
62-
any connection originating on the local machine. Any local user can gain
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database superuser privileges when connecting to this server, and could
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in principle exploit all privileges of the operating-system user running
65-
the tests. Therefore, it is not recommended that you use <literal>gmake
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check</> on machines shared with untrusted users. Instead, run the tests
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after completing the installation, as described in the next section.
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</para>
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<para>
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On Unix-like machines, this danger can be avoided if the temporary
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server's socket file is made inaccessible to other users, for example
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by running the tests in a protected chroot. On Windows, the temporary
74-
server opens a locally-accessible TCP socket, so filesystem protections
75-
cannot help.
61+
On systems lacking Unix-domain sockets, notably Windows, this test method
62+
starts a temporary server configured to accept any connection originating
63+
on the local machine. Any local user can gain database superuser
64+
privileges when connecting to this server, and could in principle exploit
65+
all privileges of the operating-system user running the tests. Therefore,
66+
it is not recommended that you use <literal>gmake check</> on an affected
67+
system shared with untrusted users. Instead, run the tests after
68+
completing the installation, as described in the next section.
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</para>
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</warning>
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‎src/test/regress/.gitignore

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Original file line numberDiff line numberDiff line change
@@ -1,3 +1,5 @@
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/pqsignal.c
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13
# Local binaries
24
/pg_regress
35

‎src/test/regress/GNUmakefile

Lines changed: 7 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -43,13 +43,18 @@ EXTRADEFS = '-DHOST_TUPLE="$(host_tuple)"' \
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all: pg_regress$(X)
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46-
pg_regress$(X): pg_regress.o pg_regress_main.o | submake-libpgport
46+
pg_regress$(X): pg_regress.o pg_regress_main.o pqsignal.o | submake-libpgport
4747
$(CC) $(CFLAGS) $^ $(LDFLAGS) $(LDFLAGS_EX) $(LIBS) -o $@
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# dependencies ensure that path changes propagate
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pg_regress.o: pg_regress.c $(top_builddir)/src/port/pg_config_paths.h
5151
$(CC) $(CFLAGS) $(CPPFLAGS) -I$(top_builddir)/src/port $(EXTRADEFS) -c -o $@ $<
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53+
# Pull in pqsignal like initdb does.
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pqsignal.c: % : $(top_srcdir)/src/interfaces/libpq/%
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rm -f $@ && $(LN_S) $< .
56+
pqsignal.o: override CPPFLAGS += -I$(libpq_srcdir)
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5358
$(top_builddir)/src/port/pg_config_paths.h: $(top_builddir)/src/Makefile.global
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$(MAKE) -C $(top_builddir)/src/port pg_config_paths.h
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@@ -166,7 +171,7 @@ bigcheck: all tablespace-setup
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clean distclean maintainer-clean: clean-lib
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# things built by `all' target
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rm -f $(OBJS) refint$(DLSUFFIX) autoinc$(DLSUFFIX) dummy_seclabel$(DLSUFFIX)
169-
rm -f pg_regress_main.o pg_regress.o pg_regress$(X)
174+
rm -f pqsignal.c pg_regress_main.o pg_regress.o pqsignal.o pg_regress$(X)
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# things created by various check targets
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rm -f $(output_files) $(input_files)
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rm -rf testtablespace

‎src/test/regress/pg_regress.c

Lines changed: 102 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -30,6 +30,8 @@
3030
#endif
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#include "getopt_long.h"
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#include "libpq/pqcomm.h" /* needed for UNIXSOCK_PATH() */
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#include "libpq/pqsignal.h"
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#include "pg_config_paths.h"
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/* for resultmap we need a list of pairs of strings */
@@ -109,6 +111,12 @@ static const char *progname;
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static char *logfilename;
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static FILE *logfile;
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static char *difffilename;
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static const char *sockdir;
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#ifdef HAVE_UNIX_SOCKETS
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static const char *temp_sockdir;
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static char sockself[MAXPGPATH];
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static char socklock[MAXPGPATH];
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#endif
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static _resultmap *resultmap = NULL;
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@@ -307,6 +315,81 @@ stop_postmaster(void)
307315
}
308316
}
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318+
#ifdef HAVE_UNIX_SOCKETS
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/*
320+
* Remove the socket temporary directory. pg_regress never waits for a
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* postmaster exit, so it is indeterminate whether the postmaster has yet to
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* unlink the socket and lock file. Unlink them here so we can proceed to
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* remove the directory. Ignore errors; leaking a temporary directory is
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* unimportant. This can run from a signal handler. The code is not
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* acceptable in a Windows signal handler (see initdb.c:trapsig()), but
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* Windows is not a HAVE_UNIX_SOCKETS platform.
327+
*/
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static void
329+
remove_temp(void)
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{
331+
unlink(sockself);
332+
unlink(socklock);
333+
rmdir(temp_sockdir);
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}
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/*
337+
* Signal handler that calls remove_temp() and reraises the signal.
338+
*/
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static void
340+
signal_remove_temp(int signum)
341+
{
342+
remove_temp();
343+
344+
pqsignal(signum, SIG_DFL);
345+
raise(signum);
346+
}
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/*
349+
* Create a temporary directory suitable for the server's Unix-domain socket.
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* The directory will have mode 0700 or stricter, so no other OS user can open
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* our socket to exploit our use of trust authentication. Most systems
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* constrain the length of socket paths well below _POSIX_PATH_MAX, so we
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* place the directory under /tmp rather than relative to the possibly-deep
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* current working directory.
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*
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* Compared to using the compiled-in DEFAULT_PGSOCKET_DIR, this also permits
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* testing to work in builds that relocate it to a directory not writable to
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* the build/test user.
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*/
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static const char *
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make_temp_sockdir(void)
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{
363+
char *template = strdup("/tmp/pg_regress-XXXXXX");
364+
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temp_sockdir = mkdtemp(template);
366+
if (temp_sockdir == NULL)
367+
{
368+
fprintf(stderr, _("%s: could not create directory \"%s\": %s\n"),
369+
progname, template, strerror(errno));
370+
exit(2);
371+
}
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/* Stage file names for remove_temp(). Unsafe in a signal handler. */
374+
UNIXSOCK_PATH(sockself, port, temp_sockdir);
375+
snprintf(socklock, sizeof(socklock), "%s.lock", sockself);
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377+
/* Remove the directory during clean exit. */
378+
atexit(remove_temp);
379+
380+
/*
381+
* Remove the directory before dying to the usual signals. Omit SIGQUIT,
382+
* preserving it as a quick, untidy exit.
383+
*/
384+
pqsignal(SIGHUP, signal_remove_temp);
385+
pqsignal(SIGINT, signal_remove_temp);
386+
pqsignal(SIGPIPE, signal_remove_temp);
387+
pqsignal(SIGTERM, signal_remove_temp);
388+
389+
return temp_sockdir;
390+
}
391+
#endif /* HAVE_UNIX_SOCKETS */
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310393
/*
311394
* Always exit through here, not through plain exit(), to ensure we make
312395
* an effort to shut down a temp postmaster
@@ -768,8 +851,7 @@ initialize_environment(void)
768851
* the wrong postmaster, or otherwise behave in nondefault ways. (Note
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* we also use psql's -X switch consistently, so that ~/.psqlrc files
770853
* won't mess things up.) Also, set PGPORT to the temp port, and set
771-
* or unset PGHOST depending on whether we are using TCP or Unix
772-
* sockets.
854+
* PGHOST depending on whether we are using TCP or Unix sockets.
773855
*/
774856
unsetenv("PGDATABASE");
775857
unsetenv("PGUSER");
@@ -778,10 +860,19 @@ initialize_environment(void)
778860
unsetenv("PGREQUIRESSL");
779861
unsetenv("PGCONNECT_TIMEOUT");
780862
unsetenv("PGDATA");
863+
#ifdef HAVE_UNIX_SOCKETS
781864
if (hostname != NULL)
782865
doputenv("PGHOST", hostname);
783866
else
784-
unsetenv("PGHOST");
867+
{
868+
sockdir = getenv("PG_REGRESS_SOCK_DIR");
869+
if (!sockdir)
870+
sockdir = make_temp_sockdir();
871+
doputenv("PGHOST", sockdir);
872+
}
873+
#else
874+
doputenv("PGHOST", hostname);
875+
#endif
785876
unsetenv("PGHOSTADDR");
786877
if (port != -1)
787878
{
@@ -2084,7 +2175,9 @@ regression_main(int argc, char *argv[], init_function ifunc, test_function tfunc
20842175
/*
20852176
* To reduce chances of interference with parallel installations, use
20862177
* a port number starting in the private range (49152-65535)
2087-
* calculated from the version number.
2178+
* calculated from the version number. This aids !HAVE_UNIX_SOCKETS
2179+
* systems; elsewhere, the use of a private socket directory already
2180+
* prevents interference.
20882181
*/
20892182
port = 0xC000 | (PG_VERSION_NUM & 0x3FFF);
20902183

@@ -2253,10 +2346,11 @@ regression_main(int argc, char *argv[], init_function ifunc, test_function tfunc
22532346
*/
22542347
header(_("starting postmaster"));
22552348
snprintf(buf, sizeof(buf),
2256-
SYSTEMQUOTE "\"%s/postgres\" -D \"%s/data\" -F%s -c \"listen_addresses=%s\" > \"%s/log/postmaster.log\" 2>&1" SYSTEMQUOTE,
2257-
bindir, temp_install,
2258-
debug ? " -d 5" : "",
2259-
hostname ? hostname : "",
2349+
SYSTEMQUOTE "\"%s/postgres\" -D \"%s/data\" -F%s "
2350+
"-c \"listen_addresses=%s\" -k \"%s\" "
2351+
"> \"%s/log/postmaster.log\" 2>&1" SYSTEMQUOTE,
2352+
bindir, temp_install, debug ? " -d 5" : "",
2353+
hostname ? hostname : "", sockdir ? sockdir : "",
22602354
outputdir);
22612355
postmaster_pid = spawn_process(buf);
22622356
if (postmaster_pid == INVALID_PID)

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