[LTP] [PATCH 4/4] syscalls/modify_ldt: Refactor modify_ldt01 into new API
Andrea Cervesato
andrea.cervesato@suse.com
Tue Mar 25 11:10:51 CET 2025
Hi!
So this is a test which is testing if modify_ldt syscall is producing
the right errors according to invalid inputs. It's a pretty common type
of test in LTP and we can extend it to all the other errors as well
Basically, we need to merge simple tests checking for errors into a
single one using test cases.
Some comments below.
On 3/24/25 21:45, Ricardo B. Marliere via ltp wrote:
> From: Ricardo B. Marlière <rbm@suse.com>
>
> Also split its three blocks into individual tests.
>
> Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
> ---
> testcases/kernel/syscalls/modify_ldt/.gitignore | 8 +-
> .../kernel/syscalls/modify_ldt/modify_ldt01.c | 234 ++-------------------
> .../kernel/syscalls/modify_ldt/modify_ldt04.c | 32 +++
> .../kernel/syscalls/modify_ldt/modify_ldt05.c | 37 ++++
> 4 files changed, 92 insertions(+), 219 deletions(-)
>
> diff --git a/testcases/kernel/syscalls/modify_ldt/.gitignore b/testcases/kernel/syscalls/modify_ldt/.gitignore
> index c0b8bbf5875af453b4880ef4b717fdb40d109ee7..76fe2f3f0592f92fa87963597d0c03e2fd81e2da 100644
> --- a/testcases/kernel/syscalls/modify_ldt/.gitignore
> +++ b/testcases/kernel/syscalls/modify_ldt/.gitignore
> @@ -1,3 +1,5 @@
> -/modify_ldt01
> -/modify_ldt02
> -/modify_ldt03
> +modify_ldt01
> +modify_ldt02
> +modify_ldt03
> +modify_ldt04
> +modify_ldt05
> diff --git a/testcases/kernel/syscalls/modify_ldt/modify_ldt01.c b/testcases/kernel/syscalls/modify_ldt/modify_ldt01.c
> index 684e53772414ae468b4f168578596eabb27ef18b..45e9649f91b68f28c8adc081183cfbd1b1c3ca88 100644
> --- a/testcases/kernel/syscalls/modify_ldt/modify_ldt01.c
> +++ b/testcases/kernel/syscalls/modify_ldt/modify_ldt01.c
> @@ -1,230 +1,32 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> /*
> - *
> - * Copyright (c) International Business Machines Corp., 2001
> - *
> - * This program is free software; you can redistribute it and/or modify
> - * it under the terms of the GNU General Public License as published by
> - * the Free Software Foundation; either version 2 of the License, or
> - * (at your option) any later version.
> - *
> - * This program 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 General Public License for more details.
> - *
> - * You should have received a copy of the GNU General Public License
> - * along with this program; if not, write to the Free Software
> - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> - */
> -
> -/*
> - * NAME
> - * modify_ldt01.c
> - *
> - * DESCRIPTION
> - * Testcase to check the error conditions for modify_ldt(2)
> - *
> - * CALLS
> - * modify_ldt()
> - *
> - * ALGORITHM
> - * block1:
> - * Invoke modify_ldt() with a func value which is neither
> - * 0 or 1. Verify that ENOSYS is set.
> - * block2:
> - * Invoke mprotect() with ptr == NULL. Verify that EINVAL
> - * is set.
> - * block3:
> - * Create an LDT segment.
> - * Try to read from an invalid pointer.
> - * Verify that EFAULT is set.
> - *
> - * USAGE
> - * modify_ldt01
> - *
> - * HISTORY
> + * Copyright (c) International Business Machines Corp., 2001
> * 07/2001 Ported by Wayne Boyer
> - *
> - * RESTRICTIONS
> - * None
> + * Copyright (c) 2025 SUSE LLC Ricardo B. Marlière <rbm@suse.com>
> */
>
> -#include "config.h"
> -#include "test.h"
> -
> -TCID_DEFINE(modify_ldt01);
> -int TST_TOTAL = 1;
> -
> -#if defined(__i386__) && defined(HAVE_MODIFY_LDT)
> -
> -#ifdef HAVE_ASM_LDT_H
> -#include <asm/ldt.h>
> -#endif
> -extern int modify_ldt(int, void *, unsigned long);
> -
> -#include <asm/unistd.h>
> -#include <errno.h>
> -
> -/* Newer ldt.h files use user_desc, instead of modify_ldt_ldt_s */
> -#ifdef HAVE_STRUCT_USER_DESC
> -typedef struct user_desc modify_ldt_s;
> -#elif HAVE_STRUCT_MODIFY_LDT_LDT_S
> -typedef struct modify_ldt_ldt_s modify_ldt_s;
> -#else
> -typedef struct modify_ldt_ldt_t {
> - unsigned int entry_number;
> - unsigned long int base_addr;
> - unsigned int limit;
> - unsigned int seg_32bit:1;
> - unsigned int contents:2;
> - unsigned int read_exec_only:1;
> - unsigned int limit_in_pages:1;
> - unsigned int seg_not_present:1;
> - unsigned int useable:1;
> - unsigned int empty:25;
> -} modify_ldt_s;
> -#endif
> -
> -int create_segment(void *, size_t);
> -void cleanup(void);
> -void setup(void);
> -
> -int main(int ac, char **av)
> -{
> - int lc;
> -
> - void *ptr;
> - int retval, func;
> -
> - int seg[4];
> -
> - tst_parse_opts(ac, av, NULL, NULL);
> -
> - setup();
> -
> - for (lc = 0; TEST_LOOPING(lc); lc++) {
> -
> - /* reset tst_count in case we are looping */
> - tst_count = 0;
> -
> - /*
> - * Check for ENOSYS.
> - */
> - ptr = malloc(10);
> - func = 100;
> - retval = modify_ldt(func, ptr, sizeof(ptr));
> - if (retval < 0) {
> - if (errno != ENOSYS) {
> - tst_resm(TFAIL, "modify_ldt() set invalid "
> - "errno, expected ENOSYS, got: %d",
> - errno);
> - } else {
> - tst_resm(TPASS,
> - "modify_ldt() set expected errno");
> - }
> - } else {
> - tst_resm(TFAIL, "modify_ldt error: "
> - "unexpected return value %d", retval);
> - }
> -
> - free(ptr);
> -
> - /*
> - * Check for EINVAL
> - */
> - ptr = 0;
> -
> - retval = modify_ldt(1, ptr, sizeof(ptr));
> - if (retval < 0) {
> - if (errno != EINVAL) {
> - tst_resm(TFAIL, "modify_ldt() set invalid "
> - "errno, expected EINVAL, got: %d",
> - errno);
> - } else {
> - tst_resm(TPASS,
> - "modify_ldt() set expected errno");
> - }
> - } else {
> - tst_resm(TFAIL, "modify_ldt error: "
> - "unexpected return value %d", retval);
> - }
> -
> - /*
> - * Create a new LDT segment.
> - */
> - if (create_segment(seg, sizeof(seg)) == -1) {
> - tst_brkm(TBROK, cleanup, "Creation of segment failed");
> - }
> -
> - /*
> - * Check for EFAULT
> - */
> - ptr = sbrk(0);
> -
> - retval = modify_ldt(0, ptr + 0xFFF, sizeof(ptr));
> - if (retval < 0) {
> - if (errno != EFAULT) {
> - tst_resm(TFAIL, "modify_ldt() set invalid "
> - "errno, expected EFAULT, got: %d",
> - errno);
> - } else {
> - tst_resm(TPASS,
> - "modify_ldt() set expected errno");
> - }
> - } else {
> - tst_resm(TFAIL, "modify_ldt error: "
> - "unexpected return value %d", retval);
> - }
> - }
> - cleanup();
> - tst_exit();
> -}
> -
> -/*
> - * create_segment() -
> +/*\
> + * Verify that a ENOSYS error is thrown when calling modify_ldt with a func
> + * which is neither 0 or 1.
> */
> -int create_segment(void *seg, size_t size)
> -{
> - modify_ldt_s entry;
> -
> - entry.entry_number = 0;
> - entry.base_addr = (unsigned long)seg;
> - entry.limit = size;
> - entry.seg_32bit = 1;
> - entry.contents = 0;
> - entry.read_exec_only = 0;
> - entry.limit_in_pages = 0;
> - entry.seg_not_present = 0;
>
> - return modify_ldt(1, &entry, sizeof(entry));
> -}
> -
> -void setup(void)
> -{
> +#include "tst_test.h"
>
> - tst_sig(FORK, DEF_HANDLER, cleanup);
> -
> - TEST_PAUSE;
> -}
> +#ifdef __i386__
> +#include "lapi/ldt.h"
>
> -void cleanup(void)
> +void run(void)
> {
> + char buf[sizeof(struct user_desc)];
>
> + TEST(modify_ldt(100, buf, sizeof(buf)));
> + TST_EXP_EQ_LI(TST_ERR, ENOSYS);
We can use TST_EXP_FAIL() which is a shorter version.
Also, when we are testing syscalls, we usually (not always for
historical reasons) use guarded buffers for memory input. Please take a
look at the "tst_test::bufs" attribute. Also in this case, LTP code is
the way to understand how to use them.
> }
>
> -#elif HAVE_MODIFY_LDT
> -int main(void)
> -{
> - tst_brkm(TCONF,
> - NULL,
> - "modify_ldt is available but not tested on the platform than __i386__");
> -}
> +static struct tst_test test = {
> + .test_all = run,
> +};
>
> #else
> -int main(void)
> -{
> - tst_resm(TINFO, "modify_ldt01 test only for ix86");
> - tst_exit();
> -}
> -
> -#endif /* defined(__i386__) */
> +TST_TEST_TCONF("Test supported only on i386");
> +#endif /* __i386__ */
> diff --git a/testcases/kernel/syscalls/modify_ldt/modify_ldt04.c b/testcases/kernel/syscalls/modify_ldt/modify_ldt04.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..91de4ca28eee389c0b49b889cc60c1a8cbde39f4
> --- /dev/null
> +++ b/testcases/kernel/syscalls/modify_ldt/modify_ldt04.c
> @@ -0,0 +1,32 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) International Business Machines Corp., 2001
> + * 07/2001 Ported by Wayne Boyer
> + * Copyright (c) 2025 SUSE LLC Ricardo B. Marlière <rbm@suse.com>
> + */
> +
> +/*\
> + * Verify that a EINVAL error is thrown when calling modify_ldt to write a
> + * NULL pointer.
> + */
> +
> +#include "tst_test.h"
> +
> +#ifdef __i386__
> +#include "lapi/ldt.h"
> +
> +void run(void)
> +{
> + void *ptr = 0;
> +
> + TEST(modify_ldt(1, ptr, sizeof(ptr)));
> + TST_EXP_EQ_LI(TST_ERR, EINVAL);
> +}
> +
> +static struct tst_test test = {
> + .test_all = run,
> +};
> +
> +#else
> +TST_TEST_TCONF("Test supported only on i386");
> +#endif /* __i386__ */
> diff --git a/testcases/kernel/syscalls/modify_ldt/modify_ldt05.c b/testcases/kernel/syscalls/modify_ldt/modify_ldt05.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..77c32ae763edc00d324e6eecf79bedebb3413c24
> --- /dev/null
> +++ b/testcases/kernel/syscalls/modify_ldt/modify_ldt05.c
> @@ -0,0 +1,37 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) International Business Machines Corp., 2001
> + * 07/2001 Ported by Wayne Boyer
> + * Copyright (c) 2025 SUSE LLC Ricardo B. Marlière <rbm@suse.com>
> + */
> +
> +/*\
> + * Verify that a EFAULT error is thrown when calling modify_ldt to read an
> + * invalid pointer.
> + */
> +
> +#include "tst_test.h"
> +
> +#ifdef __i386__
> +#include "lapi/ldt.h"
> +#include "common.h"
> +
> +void run(void)
> +{
> + int seg[4];
> + void *ptr = sbrk(0);
> +
> + if (create_segment(seg, sizeof(seg)) == -1)
> + tst_brk(TBROK, "Creation of segment failed");
> +
> + TEST(modify_ldt(0, ptr + 0xFFF, sizeof(ptr)));
> + TST_EXP_EQ_LI(TST_ERR, EFAULT);
> +}
> +
> +static struct tst_test test = {
> + .test_all = run,
> +};
> +
> +#else
> +TST_TEST_TCONF("Test supported only on i386");
> +#endif /* __i386__ */
>
Kind regards,
Andrea Cervesato
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