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wordexp: Split out command execution tests from posix/wordexp-test

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Once wordexp switches to posix_spawn, testing for command execution
based on fork handlers will not work anymore.  Therefore, move these
subtests into  a new test, posix/tst-wordexp-nocmd, which uses a
different form of command execution detection, based on PID
namespaces.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Florian Weimer 2019-10-08 13:04:15 +02:00
parent ca602c1536
commit 3203690170
4 changed files with 194 additions and 84 deletions
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13
ChangeLog
View File

@ -1,3 +1,16 @@
2019-10-08 Florian Weimer <fweimer@redhat.com>
* posix/Makefile (tests): Add tst-wordexp-nocmd.
* posix/wordexp-test.c (__app_register_atfork): Remove function.
(registered_forks): Remove variable.
(register_fork): Remove function.
(test_case): Remove WRDE_NOCMD tests.
(main): Do not set up fork tracking. Remove integer overflow in
division tests.
(testit): Do not check for unexpected forks.
* posix/tst-wordexp-nocmd.c: New file containing the tests removed
from posix/wordexp-test.c.
2019-10-07 Florian Weimer <fweimer@redhat.com>
nptl: Move pthread_attr_setschedparam implementation into libc.

3
posix/Makefile
View File

@ -100,7 +100,8 @@ tests := test-errno tstgetopt testfnm runtests runptests \
tst-posix_fadvise tst-posix_fadvise64 \
tst-sysconf-empty-chroot tst-glob_symlinks tst-fexecve \
tst-glob-tilde test-ssize-max tst-spawn4 bug-regex37 \
bug-regex38 tst-regcomp-truncated tst-spawn-chdir
bug-regex38 tst-regcomp-truncated tst-spawn-chdir \
tst-wordexp-nocmd
tests-internal := bug-regex5 bug-regex20 bug-regex33 \
tst-rfc3484 tst-rfc3484-2 tst-rfc3484-3 \
tst-glob_lstat_compat tst-spawn4-compat

179
posix/tst-wordexp-nocmd.c Normal file
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@ -0,0 +1,179 @@
/* Test for (lack of) command execution in wordexp.
Copyright (C) 1997-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* This test optionally counts PIDs in a PID namespace to detect
forks. Without kernel support for that, it will merely look at the
error codes from wordexp to check that no command execution
happens. */
#include <sched.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <support/check.h>
#include <support/namespace.h>
#include <support/xunistd.h>
#include <wordexp.h>
/* Set to true if the test runs in a PID namespace and can therefore
use next_pid below. */
static bool pid_tests_supported;
/* The next PID, as returned from next_pid below. Only meaningful if
pid_tests_supported. */
static pid_t expected_pid;
/* Allocate the next PID and return it. The process is terminated.
Note that the test itself advances the next PID. */
static pid_t
next_pid (void)
{
pid_t pid = xfork ();
if (pid == 0)
_exit (0);
xwaitpid (pid, NULL, 0);
return pid;
}
/* Check that evaluating PATTERN with WRDE_NOCMD results in
EXPECTED_ERROR. */
static void
expect_failure (const char *pattern, int expected_error)
{
printf ("info: testing pattern: %s\n", pattern);
wordexp_t w;
TEST_COMPARE (wordexp (pattern, &w, WRDE_NOCMD), expected_error);
if (pid_tests_supported)
TEST_COMPARE (expected_pid++, next_pid ());
}
/* Run all the tests. Invoked with different IFS values. */
static void
run_tests (void)
{
/* Integer overflow in division. */
{
static const char *const numbers[] = {
"0",
"1",
"65536",
"2147483648",
"4294967296"
"9223372036854775808",
"18446744073709551616",
"170141183460469231731687303715884105728",
"340282366920938463463374607431768211456",
NULL
};
for (const char *const *num = numbers; *num != NULL; ++num)
{
wordexp_t w;
char pattern[256];
snprintf (pattern, sizeof (pattern), "$[(-%s)/(-1)]", *num);
int ret = wordexp (pattern, &w, WRDE_NOCMD);
if (ret == 0)
{
/* If the call is successful, the result must match the
original number. */
TEST_COMPARE (w.we_wordc, 1);
TEST_COMPARE_STRING (w.we_wordv[0], *num);
TEST_COMPARE_STRING (w.we_wordv[1], NULL);
wordfree (&w);
}
else
/* Otherwise, the test must fail with a syntax error. */
TEST_COMPARE (ret, WRDE_SYNTAX);
/* In both cases, command execution is not permitted. */
if (pid_tests_supported)
TEST_COMPARE (expected_pid++, next_pid ());
}
}
/* (Lack of) command execution tests. */
expect_failure ("$(ls)", WRDE_CMDSUB);
/* Test for CVE-2014-7817. We test 3 combinations of command
substitution inside an arithmetic expression to make sure that
no commands are executed and error is returned. */
expect_failure ("$((`echo 1`))", WRDE_CMDSUB);
expect_failure ("$((1+`echo 1`))", WRDE_CMDSUB);
expect_failure ("$((1+$((`echo 1`))))", WRDE_CMDSUB);
expect_failure ("$[1/0]", WRDE_SYNTAX); /* BZ 18100. */
}
static void
subprocess (void *closure)
{
expected_pid = 2;
if (pid_tests_supported)
TEST_COMPARE (expected_pid++, next_pid ());
/* Check that triggering command execution via wordexp results in a
PID increase. */
if (pid_tests_supported)
{
wordexp_t w;
TEST_COMPARE (wordexp ("$(echo Test)", &w, 0), 0);
TEST_COMPARE (w.we_wordc, 1);
TEST_COMPARE_STRING (w.we_wordv[0], "Test");
TEST_COMPARE_STRING (w.we_wordv[1], NULL);
wordfree (&w);
pid_t n = next_pid ();
printf ("info: self-test resulted in PID %d (processes created: %d)\n",
(int) n, (int) (n - expected_pid));
TEST_VERIFY (n > expected_pid);
expected_pid = n + 1;
}
puts ("info: testing without IFS");
unsetenv ("IFS");
run_tests ();
puts ("info: testing with IFS");
TEST_COMPARE (setenv ("IFS", " \t\n", 1), 0);
run_tests ();
}
static int
do_test (void)
{
support_become_root ();
#ifdef CLONE_NEWPID
if (unshare (CLONE_NEWPID) != 0)
printf ("warning: unshare (CLONE_NEW_PID) failed: %m\n"
"warning: This leads to reduced test coverage.\n");
else
pid_tests_supported = true;
#else
printf ("warning: CLONE_NEW_PID not available.\n"
"warning: This leads to reduced test coverage.\n");
#endif
/* CLONE_NEWPID only has an effect after fork. */
support_isolate_in_subprocess (subprocess, NULL);
return 0;
}
#include <support/test-driver.c>

83
posix/wordexp-test.c
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@ -31,23 +31,6 @@
#define IFS " \n\t"
extern int __register_atfork (void (*) (void), void (*) (void), void (*) (void), void *);
static int __app_register_atfork (void (*prepare) (void), void (*parent) (void), void (*child) (void))
{
return __register_atfork (prepare, parent, child, __dso_handle);
}
/* Number of forks seen. */
static int registered_forks;
/* For each fork increment the fork count. */
static void
register_fork (void)
{
registered_forks++;
}
struct test_case_struct
{
int retval;
@ -217,7 +200,6 @@ struct test_case_struct
{ WRDE_BADCHAR, NULL, "close-paren)", 0, 0, { NULL, }, IFS },
{ WRDE_BADCHAR, NULL, "{open-brace", 0, 0, { NULL, }, IFS },
{ WRDE_BADCHAR, NULL, "close-brace}", 0, 0, { NULL, }, IFS },
{ WRDE_CMDSUB, NULL, "$(ls)", WRDE_NOCMD, 0, { NULL, }, IFS },
{ WRDE_BADVAL, NULL, "$var", WRDE_UNDEF, 0, { NULL, }, IFS },
{ WRDE_BADVAL, NULL, "$9", WRDE_UNDEF, 0, { NULL, }, IFS },
{ WRDE_SYNTAX, NULL, "$[50+20))", 0, 0, { NULL, }, IFS },
@ -227,17 +209,10 @@ struct test_case_struct
{ WRDE_SYNTAX, NULL, "$((2+))", 0, 0, { NULL, }, IFS },
{ WRDE_SYNTAX, NULL, "`", 0, 0, { NULL, }, IFS },
{ WRDE_SYNTAX, NULL, "$((010+4+))", 0, 0, { NULL }, IFS },
/* Test for CVE-2014-7817. We test 3 combinations of command
substitution inside an arithmetic expression to make sure that
no commands are executed and error is returned. */
{ WRDE_CMDSUB, NULL, "$((`echo 1`))", WRDE_NOCMD, 0, { NULL, }, IFS },
{ WRDE_CMDSUB, NULL, "$((1+`echo 1`))", WRDE_NOCMD, 0, { NULL, }, IFS },
{ WRDE_CMDSUB, NULL, "$((1+$((`echo 1`))))", WRDE_NOCMD, 0, { NULL, }, IFS },
{ WRDE_SYNTAX, NULL, "`\\", 0, 0, { NULL, }, IFS }, /* BZ 18042 */
{ WRDE_SYNTAX, NULL, "${", 0, 0, { NULL, }, IFS }, /* BZ 18043 */
{ WRDE_SYNTAX, NULL, "L${a:", 0, 0, { NULL, }, IFS }, /* BZ 18043#c4 */
{ WRDE_SYNTAX, NULL, "$[1/0]", WRDE_NOCMD, 0, {NULL, }, IFS }, /* BZ 18100 */
{ -1, NULL, NULL, 0, 0, { NULL, }, IFS },
};
@ -290,15 +265,6 @@ main (int argc, char *argv[])
return -1;
}
/* If we are not allowed to do command substitution, we install
fork handlers to verify that no forks happened. No forks should
happen at all if command substitution is disabled. */
if (__app_register_atfork (register_fork, NULL, NULL) != 0)
{
printf ("Failed to register fork handler.\n");
return -1;
}
for (test = 0; test_case[test].retval != -1; test++)
if (testit (&test_case[test]))
++fail;
@ -363,45 +329,6 @@ main (int argc, char *argv[])
++fail;
}
/* Integer overflow in division. */
{
static const char *const numbers[] = {
"0",
"1",
"65536",
"2147483648",
"4294967296"
"9223372036854775808",
"18446744073709551616",
"170141183460469231731687303715884105728",
"340282366920938463463374607431768211456",
NULL
};
for (const char *const *num = numbers; *num; ++num)
{
wordexp_t p;
char pattern[256];
snprintf (pattern, sizeof (pattern), "$[(-%s)/(-1)]", *num);
int ret = wordexp (pattern, &p, WRDE_NOCMD);
if (ret == 0)
{
if (p.we_wordc != 1 || strcmp (p.we_wordv[0], *num) != 0)
{
printf ("Integer overflow for \"%s\" failed", pattern);
++fail;
}
wordfree (&p);
}
else if (ret != WRDE_SYNTAX)
{
printf ("Integer overflow for \"%s\" failed with %d",
pattern, ret);
++fail;
}
}
}
puts ("tests completed, now cleaning up");
/* Clean up */
@ -472,9 +399,6 @@ testit (struct test_case_struct *tc)
fflush (NULL);
const char *words = at_page_end (tc->words);
if (tc->flags & WRDE_NOCMD)
registered_forks = 0;
if (tc->flags & WRDE_APPEND)
{
/* initial wordexp() call, to be appended to */
@ -486,13 +410,6 @@ testit (struct test_case_struct *tc)
}
retval = wordexp (words, &we, tc->flags);
if ((tc->flags & WRDE_NOCMD)
&& (registered_forks > 0))
{
printf ("FAILED fork called for WRDE_NOCMD\n");
return 1;
}
if (tc->flags & WRDE_DOOFFS)
start_offs = sav_we.we_offs;