[LTP] [PATCH v1] open15: allow restricted O_CREAT of FIFOs and regular files

[LTP] [PATCH v1] open15: allow restricted O_CREAT of FIFOs and regular files

[Wei Gao via ltp]

Fix: #574

Signed-off-by: Wei Gao <wegao@suse.com>
---
 runtest/syscalls                          |   1 +
 testcases/kernel/syscalls/open/.gitignore |   1 +
 testcases/kernel/syscalls/open/open15.c   | 188 ++++++++++++++++++++++
 3 files changed, 190 insertions(+)
 create mode 100644 testcases/kernel/syscalls/open/open15.c

diff --git a/runtest/syscalls b/runtest/syscalls
index 4f1ee1f34..4152e1e5f 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -935,6 +935,7 @@ open11 open11
 open12 open12
 open13 open13
 open14 open14
+open15 open15
 
 openat01 openat01
 openat02 openat02
diff --git a/testcases/kernel/syscalls/open/.gitignore b/testcases/kernel/syscalls/open/.gitignore
index 001d874d6..af5997572 100644
--- a/testcases/kernel/syscalls/open/.gitignore
+++ b/testcases/kernel/syscalls/open/.gitignore
@@ -12,3 +12,4 @@
 /open12_child
 /open13
 /open14
+/open15
diff --git a/testcases/kernel/syscalls/open/open15.c b/testcases/kernel/syscalls/open/open15.c
new file mode 100644
index 000000000..f0eec08e7
--- /dev/null
+++ b/testcases/kernel/syscalls/open/open15.c
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2023 Wei Gao <wegao@suse.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * Verify disallows open of FIFOs or regular files not owned by the user in world
+ * writable sticky directories
+ *
+ * Linux commit 30aba6656f61ed44cba445a3c0d38b296fa9e8f5
+ */
+
+#include <pwd.h>
+#include <stdlib.h>
+#include "tst_test.h"
+#include "tst_safe_file_at.h"
+
+#define  FILENAME  "setuid04_testfile"
+#define  DIR "ltp_tmp_check1"
+#define  TEST_FILE "test_file_1"
+#define  TEST_FIFO "test_fifo_1"
+#define  LTP_USER1 "ltp_user1"
+#define  LTP_USER2 "ltp_user2"
+#define  CONCAT(dir, filename) dir "/" filename
+#define  PROTECTED_REGULAR "/proc/sys/fs/protected_regular"
+#define  PROTECTED_FIFOS "/proc/sys/fs/protected_fifos"
+
+static int LTP_USER1_UID;
+static int LTP_USER2_UID;
+static int dir_fd;
+
+static void run(void)
+{
+	int pid;
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 0);
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 0);
+
+	pid = SAFE_FORK();
+	if (pid == 0) {
+		SAFE_SETUID(LTP_USER1_UID);
+
+		int fd = SAFE_OPENAT(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777);
+
+		SAFE_CLOSE(fd);
+		fd = SAFE_MKFIFO(CONCAT(DIR, TEST_FIFO), 0777);
+		SAFE_CLOSE(fd);
+
+		TST_CHECKPOINT_WAKE(0);
+		exit(0);
+	}
+
+	TST_CHECKPOINT_WAIT(0);
+
+	pid = SAFE_FORK();
+
+	if (pid == 0) {
+		SAFE_SETUID(LTP_USER2_UID);
+
+		int fd = SAFE_OPENAT(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777);
+
+		tst_res(TPASS, "check protect_regural == 0 pass");
+		SAFE_CLOSE(fd);
+
+		fd = SAFE_OPEN(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT);
+		tst_res(TPASS, "check protect_fifos == 0 pass");
+		SAFE_CLOSE(fd);
+
+		TST_CHECKPOINT_WAKE(1);
+		exit(0);
+	}
+
+	TST_CHECKPOINT_WAIT(1);
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 1);
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 1);
+
+	pid = SAFE_FORK();
+
+	if (pid == 0) {
+		SAFE_SETUID(LTP_USER2_UID);
+
+		TEST(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777));
+		if (TST_RET == -1 && TST_ERR == EACCES)
+			tst_res(TPASS, "check protect_regural == 1 pass");
+		else
+			tst_res(TFAIL | TERRNO, "check protect_regural == 1 failed");
+
+		TEST(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777));
+		if (TST_RET == -1 && TST_ERR == EACCES)
+			tst_res(TPASS, "check protect_fifos == 1 pass");
+		else
+			tst_res(TFAIL | TERRNO, "check protect_fifos == 1 failed");
+
+		TST_CHECKPOINT_WAKE(2);
+		exit(0);
+	}
+
+	TST_CHECKPOINT_WAIT(2);
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 2);
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 2);
+	SAFE_CHMOD(DIR, 0020 | S_ISVTX);
+
+	pid = SAFE_FORK();
+
+	if (pid == 0) {
+		SAFE_SETUID(LTP_USER2_UID);
+
+		TEST(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777));
+		if (TST_RET == -1 && TST_ERR == EACCES)
+			tst_res(TPASS, "check protect_regural == 2 pass");
+		else
+			tst_res(TFAIL | TERRNO, "check protect_regural == 2 failed");
+
+		TEST(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777));
+		if (TST_RET == -1 && TST_ERR == EACCES)
+			tst_res(TPASS, "check protect_fifos == 2 pass");
+		else
+			tst_res(TFAIL | TERRNO, "check protect_fifos == 2 failed");
+
+		TST_CHECKPOINT_WAKE(3);
+		exit(0);
+	}
+
+	TST_CHECKPOINT_WAIT(3);
+}
+
+static int add_user(char *username)
+{
+	const char *const cmd_useradd[] = {"useradd", username, NULL};
+	struct passwd *ltpuser;
+	int rc, uid = -1;
+
+	switch ((rc = tst_cmd(cmd_useradd, NULL, NULL, TST_CMD_PASS_RETVAL))) {
+	case 0:
+	case 9:
+		ltpuser = SAFE_GETPWNAM(username);
+		uid = ltpuser->pw_uid;
+		break;
+	default:
+		tst_brk(TBROK, "Useradd failed (%d)", rc);
+	}
+
+	return uid;
+}
+
+static void del_user(char *username)
+{
+	const char *const cmd_userdel[] = {"userdel", "-r", username, NULL};
+
+	tst_cmd(cmd_userdel, NULL, NULL, TST_CMD_PASS_RETVAL);
+
+}
+
+static void setup(void)
+{
+	umask(0);
+	SAFE_MKDIR(DIR, 0777 | S_ISVTX);
+
+	dir_fd = SAFE_OPEN(DIR, O_DIRECTORY);
+
+	LTP_USER1_UID = add_user(LTP_USER1);
+	LTP_USER2_UID = add_user(LTP_USER2);
+}
+
+static void cleanup(void)
+{
+	del_user(LTP_USER1);
+	del_user(LTP_USER2);
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.cleanup = cleanup,
+	.needs_root = 1,
+	.test_all = run,
+	.needs_tmpdir = 1,
+	.forks_child = 1,
+	.save_restore = (const struct tst_path_val[]) {
+		{PROTECTED_REGULAR, NULL, TST_SR_SKIP},
+		{PROTECTED_FIFOS, NULL, TST_SR_SKIP},
+		{}
+	},
+	.needs_checkpoints = 1,
+};
-- 
2.35.3


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH v1] open15: allow restricted O_CREAT of FIFOs and regular files

[Cyril Hrubis]

Hi!
> +// SPDX-License-Identifier: GPL-2.0-only

The default license should be GPL-2.0-or-later for new tests.

> +/*
> + * Copyright (c) 2023 Wei Gao <wegao@suse.com>
> + */
> +
> +/*\
> + * [Description]
> + *
> + * Verify disallows open of FIFOs or regular files not owned by the user in world
> + * writable sticky directories
> + *
> + * Linux commit 30aba6656f61ed44cba445a3c0d38b296fa9e8f5
> + */
> +
> +#include <pwd.h>
> +#include <stdlib.h>
> +#include "tst_test.h"
> +#include "tst_safe_file_at.h"
> +
> +#define  FILENAME  "setuid04_testfile"
> +#define  DIR "ltp_tmp_check1"
> +#define  TEST_FILE "test_file_1"
> +#define  TEST_FIFO "test_fifo_1"
> +#define  LTP_USER1 "ltp_user1"
> +#define  LTP_USER2 "ltp_user2"
> +#define  CONCAT(dir, filename) dir "/" filename
> +#define  PROTECTED_REGULAR "/proc/sys/fs/protected_regular"
> +#define  PROTECTED_FIFOS "/proc/sys/fs/protected_fifos"
> +
> +static int LTP_USER1_UID;
> +static int LTP_USER2_UID;
> +static int dir_fd;
> +
> +static void run(void)
> +{
> +	int pid;
> +
> +	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 0);
> +	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 0);
> +
> +	pid = SAFE_FORK();
> +	if (pid == 0) {
> +		SAFE_SETUID(LTP_USER1_UID);
> +
> +		int fd = SAFE_OPENAT(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777);
> +
> +		SAFE_CLOSE(fd);
> +		fd = SAFE_MKFIFO(CONCAT(DIR, TEST_FIFO), 0777);
> +		SAFE_CLOSE(fd);
> +
> +		TST_CHECKPOINT_WAKE(0);
> +		exit(0);
> +	}
> +
> +	TST_CHECKPOINT_WAIT(0);

This shouldn't be checkpoint, but rather you should wait for the child
process with tst_reap_children() and the same in all the other cases.

> +	pid = SAFE_FORK();
> +
> +	if (pid == 0) {
> +		SAFE_SETUID(LTP_USER2_UID);
> +
> +		int fd = SAFE_OPENAT(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777);

This can't be SAFE_OPENAT() since it will TBROK instead of TFAIL in a
case of a failure. You have to do the TST_EXP_FD(openat(...)) instead.

And the same for all the cases that shouldn't fail.

> +		tst_res(TPASS, "check protect_regural == 0 pass");
> +		SAFE_CLOSE(fd);
> +
> +		fd = SAFE_OPEN(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT);
> +		tst_res(TPASS, "check protect_fifos == 0 pass");
> +		SAFE_CLOSE(fd);
> +
> +		TST_CHECKPOINT_WAKE(1);
> +		exit(0);
> +	}
> +
> +	TST_CHECKPOINT_WAIT(1);
> +
> +	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 1);
> +	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 1);
> +
> +	pid = SAFE_FORK();
> +
> +	if (pid == 0) {
> +		SAFE_SETUID(LTP_USER2_UID);
> +
> +		TEST(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777));
> +		if (TST_RET == -1 && TST_ERR == EACCES)
> +			tst_res(TPASS, "check protect_regural == 1 pass");
> +		else
> +			tst_res(TFAIL | TERRNO, "check protect_regural == 1 failed");


And here you have to do TST_EXP_FAIL(openat(...)) and in all the failing
cases as well.

> +		TEST(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777));
> +		if (TST_RET == -1 && TST_ERR == EACCES)
> +			tst_res(TPASS, "check protect_fifos == 1 pass");
> +		else
> +			tst_res(TFAIL | TERRNO, "check protect_fifos == 1 failed");
> +
> +		TST_CHECKPOINT_WAKE(2);
> +		exit(0);
> +	}
> +
> +	TST_CHECKPOINT_WAIT(2);
> +
> +	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 2);
> +	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 2);
> +	SAFE_CHMOD(DIR, 0020 | S_ISVTX);
> +
> +	pid = SAFE_FORK();
> +
> +	if (pid == 0) {
> +		SAFE_SETUID(LTP_USER2_UID);
> +
> +		TEST(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777));
> +		if (TST_RET == -1 && TST_ERR == EACCES)
> +			tst_res(TPASS, "check protect_regural == 2 pass");
> +		else
> +			tst_res(TFAIL | TERRNO, "check protect_regural == 2 failed");
> +
> +		TEST(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777));
> +		if (TST_RET == -1 && TST_ERR == EACCES)
> +			tst_res(TPASS, "check protect_fifos == 2 pass");
> +		else
> +			tst_res(TFAIL | TERRNO, "check protect_fifos == 2 failed");
> +
> +		TST_CHECKPOINT_WAKE(3);
> +		exit(0);
> +	}
> +
> +	TST_CHECKPOINT_WAIT(3);
> +}
> +
> +static int add_user(char *username)
> +{
> +	const char *const cmd_useradd[] = {"useradd", username, NULL};
> +	struct passwd *ltpuser;
> +	int rc, uid = -1;
> +
> +	switch ((rc = tst_cmd(cmd_useradd, NULL, NULL, TST_CMD_PASS_RETVAL))) {
> +	case 0:
> +	case 9:
> +		ltpuser = SAFE_GETPWNAM(username);
> +		uid = ltpuser->pw_uid;
> +		break;
> +	default:
> +		tst_brk(TBROK, "Useradd failed (%d)", rc);
> +	}
> +
> +	return uid;
> +}
> +
> +static void del_user(char *username)
> +{
> +	const char *const cmd_userdel[] = {"userdel", "-r", username, NULL};
> +
> +	tst_cmd(cmd_userdel, NULL, NULL, TST_CMD_PASS_RETVAL);
> +
> +}
> +
> +static void setup(void)
> +{
> +	umask(0);
> +	SAFE_MKDIR(DIR, 0777 | S_ISVTX);
> +
> +	dir_fd = SAFE_OPEN(DIR, O_DIRECTORY);
> +
> +	LTP_USER1_UID = add_user(LTP_USER1);
> +	LTP_USER2_UID = add_user(LTP_USER2);

We actually does not need to add users for these tests, we can just
choose two random UIDs and use them, since all the kernel does is to
compare the UIDs of the processes...

So we can just do:

#define LTP_USR_UID1 1000
#define LTP_USR_UID2 1001

> +}
> +
> +static void cleanup(void)
> +{
> +	del_user(LTP_USER1);
> +	del_user(LTP_USER2);
> +}
> +
> +static struct tst_test test = {
> +	.setup = setup,
> +	.cleanup = cleanup,
> +	.needs_root = 1,
> +	.test_all = run,
> +	.needs_tmpdir = 1,
> +	.forks_child = 1,
> +	.save_restore = (const struct tst_path_val[]) {
> +		{PROTECTED_REGULAR, NULL, TST_SR_SKIP},
> +		{PROTECTED_FIFOS, NULL, TST_SR_SKIP},
                                         ^
					 TST_SR_TCONF

Since we want to skip the test if these files are missing.

> +		{}
> +	},
> +	.needs_checkpoints = 1,
> +};
> -- 
> 2.35.3
> 
> 
> -- 
> Mailing list info: https://lists.linux.it/listinfo/ltp

-- 
Cyril Hrubis
chrubis@suse.cz

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v2] open15: allow restricted O_CREAT of FIFOs and regular files

[Wei Gao via ltp]

Fix: #574

Signed-off-by: Wei Gao <wegao@suse.com>
---
 runtest/syscalls                          |   1 +
 testcases/kernel/syscalls/open/.gitignore |   1 +
 testcases/kernel/syscalls/open/open15.c   | 138 ++++++++++++++++++++++
 3 files changed, 140 insertions(+)
 create mode 100644 testcases/kernel/syscalls/open/open15.c

diff --git a/runtest/syscalls b/runtest/syscalls
index 4f1ee1f34..4152e1e5f 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -935,6 +935,7 @@ open11 open11
 open12 open12
 open13 open13
 open14 open14
+open15 open15
 
 openat01 openat01
 openat02 openat02
diff --git a/testcases/kernel/syscalls/open/.gitignore b/testcases/kernel/syscalls/open/.gitignore
index 001d874d6..af5997572 100644
--- a/testcases/kernel/syscalls/open/.gitignore
+++ b/testcases/kernel/syscalls/open/.gitignore
@@ -12,3 +12,4 @@
 /open12_child
 /open13
 /open14
+/open15
diff --git a/testcases/kernel/syscalls/open/open15.c b/testcases/kernel/syscalls/open/open15.c
new file mode 100644
index 000000000..4feb1bb08
--- /dev/null
+++ b/testcases/kernel/syscalls/open/open15.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2023 Wei Gao <wegao@suse.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * Verify disallows open of FIFOs or regular files not owned by the user in world
+ * writable sticky directories
+ *
+ * commit 30aba6656f61ed44cba445a3c0d38b296fa9e8f5
+ * Author: Salvatore Mesoraca <s.mesoraca16@gmail.com>
+ * Date:   Thu Aug 23 17:00:35 2018 -0700
+ *     namei: allow restricted O_CREAT of FIFOs and regular files
+ */
+
+#include <pwd.h>
+#include <stdlib.h>
+#include "tst_test.h"
+#include "tst_safe_file_at.h"
+
+#define  FILENAME  "setuid04_testfile"
+#define  DIR "ltp_tmp_check1"
+#define  TEST_FILE "test_file_1"
+#define  TEST_FIFO "test_fifo_1"
+#define  LTP_USR_UID1 1000
+#define  LTP_USR_UID2 1001
+#define  CONCAT(dir, filename) dir "/" filename
+#define  PROTECTED_REGULAR "/proc/sys/fs/protected_regular"
+#define  PROTECTED_FIFOS "/proc/sys/fs/protected_fifos"
+
+static int dir_fd;
+
+static void run(void)
+{
+	int pid;
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 0);
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 0);
+
+	pid = SAFE_FORK();
+	if (pid == 0) {
+		SAFE_SETUID(LTP_USR_UID1);
+
+		int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
+
+		SAFE_CLOSE(fd);
+		fd = SAFE_MKFIFO(CONCAT(DIR, TEST_FIFO), 0777);
+		SAFE_CLOSE(fd);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	pid = SAFE_FORK();
+
+	if (pid == 0) {
+		SAFE_SETUID(LTP_USR_UID2);
+
+		int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
+
+		tst_res(TPASS, "check protect_regural == 0 pass");
+		SAFE_CLOSE(fd);
+
+		fd = SAFE_OPEN(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT);
+		tst_res(TPASS, "check protect_fifos == 0 pass");
+		SAFE_CLOSE(fd);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 1);
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 1);
+
+	pid = SAFE_FORK();
+
+	if (pid == 0) {
+		SAFE_SETUID(LTP_USR_UID2);
+
+		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
+
+		TST_EXP_FAIL(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777), EACCES);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 2);
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 2);
+	SAFE_CHMOD(DIR, 0020 | S_ISVTX);
+
+	pid = SAFE_FORK();
+
+	if (pid == 0) {
+		SAFE_SETUID(LTP_USR_UID2);
+
+		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
+
+		TST_EXP_FAIL(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777), EACCES);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+}
+
+static void setup(void)
+{
+	umask(0);
+	SAFE_MKDIR(DIR, 0777 | S_ISVTX);
+
+	dir_fd = SAFE_OPEN(DIR, O_DIRECTORY);
+}
+
+static void cleanup(void)
+{
+	SAFE_CLOSE(dir_fd);
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.cleanup = cleanup,
+	.needs_root = 1,
+	.test_all = run,
+	.needs_tmpdir = 1,
+	.forks_child = 1,
+	.save_restore = (const struct tst_path_val[]) {
+		{PROTECTED_REGULAR, NULL, TST_SR_TCONF},
+		{PROTECTED_FIFOS, NULL, TST_SR_TCONF},
+		{}
+	},
+	.needs_checkpoints = 1,
+};
-- 
2.35.3


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH v2] open15: allow restricted O_CREAT of FIFOs and regular files

[Cyril Hrubis]

Hi!
> +/*\
> + * [Description]
> + *
> + * Verify disallows open of FIFOs or regular files not owned by the user in world
> + * writable sticky directories
> + *
> + * commit 30aba6656f61ed44cba445a3c0d38b296fa9e8f5
> + * Author: Salvatore Mesoraca <s.mesoraca16@gmail.com>
> + * Date:   Thu Aug 23 17:00:35 2018 -0700
> + *     namei: allow restricted O_CREAT of FIFOs and regular files
> + */
> +
> +#include <pwd.h>
> +#include <stdlib.h>
> +#include "tst_test.h"
> +#include "tst_safe_file_at.h"
> +
> +#define  FILENAME  "setuid04_testfile"
> +#define  DIR "ltp_tmp_check1"
> +#define  TEST_FILE "test_file_1"
> +#define  TEST_FIFO "test_fifo_1"
> +#define  LTP_USR_UID1 1000
> +#define  LTP_USR_UID2 1001
> +#define  CONCAT(dir, filename) dir "/" filename
> +#define  PROTECTED_REGULAR "/proc/sys/fs/protected_regular"
> +#define  PROTECTED_FIFOS "/proc/sys/fs/protected_fifos"
> +
> +static int dir_fd;
> +
> +static void run(void)
> +{
> +	int pid;
> +
> +	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 0);
> +	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 0);
> +
> +	pid = SAFE_FORK();

No need to store the pid if we are not using it. We can do instead just:

	if (!SAFE_FORK()) {

> +	if (pid == 0) {
> +		SAFE_SETUID(LTP_USR_UID1);
> +
> +		int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
> +
> +		SAFE_CLOSE(fd);
> +		fd = SAFE_MKFIFO(CONCAT(DIR, TEST_FIFO), 0777);
> +		SAFE_CLOSE(fd);

This part has to be done in the test setup() otherwise the test will
fail with EEXIST with -i 2.

> +		exit(0);
> +	}
> +
> +	tst_reap_children();
> +
> +	pid = SAFE_FORK();
> +
> +	if (pid == 0) {
> +		SAFE_SETUID(LTP_USR_UID2);
> +
> +		int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
> +
> +		tst_res(TPASS, "check protect_regural == 0 pass");

The TST_EXP_FD() should print TPASS message, there is no point in adding
another.


> +		SAFE_CLOSE(fd);

This should be closed only if the fd is valid.

> +		fd = SAFE_OPEN(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT);
> +		tst_res(TPASS, "check protect_fifos == 0 pass");
> +		SAFE_CLOSE(fd);

Again this should be TST_EXP_FD().

> +		exit(0);
> +	}
> +
> +	tst_reap_children();
> +
> +	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 1);
> +	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 1);
> +
> +	pid = SAFE_FORK();
> +
> +	if (pid == 0) {
> +		SAFE_SETUID(LTP_USR_UID2);
> +
> +		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
> +
> +		TST_EXP_FAIL(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777), EACCES);
> +
> +		exit(0);
> +	}
> +
> +	tst_reap_children();
> +
> +	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 2);
> +	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 2);
> +	SAFE_CHMOD(DIR, 0020 | S_ISVTX);

I suppose that this will break the test with -i 2 as well, you need to
chmod the directory back at the end of the test.

> +	pid = SAFE_FORK();
> +
> +	if (pid == 0) {
> +		SAFE_SETUID(LTP_USR_UID2);
> +
> +		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
> +
> +		TST_EXP_FAIL(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777), EACCES);
> +
> +		exit(0);
> +	}
> +
> +	tst_reap_children();
> +}
> +
> +static void setup(void)
> +{
> +	umask(0);
> +	SAFE_MKDIR(DIR, 0777 | S_ISVTX);
> +
> +	dir_fd = SAFE_OPEN(DIR, O_DIRECTORY);
> +}
> +
> +static void cleanup(void)
> +{
> +	SAFE_CLOSE(dir_fd);
> +}
> +
> +static struct tst_test test = {
> +	.setup = setup,
> +	.cleanup = cleanup,
> +	.needs_root = 1,
> +	.test_all = run,
> +	.needs_tmpdir = 1,
> +	.forks_child = 1,
> +	.save_restore = (const struct tst_path_val[]) {
> +		{PROTECTED_REGULAR, NULL, TST_SR_TCONF},
> +		{PROTECTED_FIFOS, NULL, TST_SR_TCONF},
> +		{}
> +	},
> +	.needs_checkpoints = 1,

This should have been removed.

> +};
> -- 
> 2.35.3
> 
> 
> -- 
> Mailing list info: https://lists.linux.it/listinfo/ltp

-- 
Cyril Hrubis
chrubis@suse.cz

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v3] open15: allow restricted O_CREAT of FIFOs and regular files

[Wei Gao via ltp]

Fix: #574

Signed-off-by: Wei Gao <wegao@suse.com>
---
 runtest/syscalls                          |   1 +
 testcases/kernel/syscalls/open/.gitignore |   1 +
 testcases/kernel/syscalls/open/open15.c   | 125 ++++++++++++++++++++++
 3 files changed, 127 insertions(+)
 create mode 100644 testcases/kernel/syscalls/open/open15.c

diff --git a/runtest/syscalls b/runtest/syscalls
index 4f1ee1f34..4152e1e5f 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -935,6 +935,7 @@ open11 open11
 open12 open12
 open13 open13
 open14 open14
+open15 open15
 
 openat01 openat01
 openat02 openat02
diff --git a/testcases/kernel/syscalls/open/.gitignore b/testcases/kernel/syscalls/open/.gitignore
index 001d874d6..af5997572 100644
--- a/testcases/kernel/syscalls/open/.gitignore
+++ b/testcases/kernel/syscalls/open/.gitignore
@@ -12,3 +12,4 @@
 /open12_child
 /open13
 /open14
+/open15
diff --git a/testcases/kernel/syscalls/open/open15.c b/testcases/kernel/syscalls/open/open15.c
new file mode 100644
index 000000000..de5325e01
--- /dev/null
+++ b/testcases/kernel/syscalls/open/open15.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2023 Wei Gao <wegao@suse.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * Verify disallows open of FIFOs or regular files not owned by the user in world
+ * writable sticky directories
+ *
+ * commit 30aba6656f61ed44cba445a3c0d38b296fa9e8f5
+ * Author: Salvatore Mesoraca <s.mesoraca16@gmail.com>
+ * Date:   Thu Aug 23 17:00:35 2018 -0700
+ *     namei: allow restricted O_CREAT of FIFOs and regular files
+ */
+
+#include <pwd.h>
+#include <stdlib.h>
+#include "tst_test.h"
+#include "tst_safe_file_at.h"
+
+#define  FILENAME  "setuid04_testfile"
+#define  DIR "ltp_tmp_check1"
+#define  TEST_FILE "test_file_1"
+#define  TEST_FIFO "test_fifo_1"
+#define  LTP_USR_UID1 1000
+#define  LTP_USR_UID2 1001
+#define  CONCAT(dir, filename) dir "/" filename
+#define  PROTECTED_REGULAR "/proc/sys/fs/protected_regular"
+#define  PROTECTED_FIFOS "/proc/sys/fs/protected_fifos"
+
+static int dir_fd;
+
+static void run(void)
+{
+	int pid;
+
+	SAFE_CHMOD(DIR, 0777 | S_ISVTX);
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 0);
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 0);
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(LTP_USR_UID1);
+
+		int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
+
+		SAFE_CLOSE(fd);
+
+		SAFE_MKFIFO(CONCAT(DIR, TEST_FIFO), 0777);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(LTP_USR_UID2);
+
+		int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
+
+		SAFE_CLOSE(fd);
+
+		fd = TST_EXP_FD(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777));
+		SAFE_CLOSE(fd);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 1);
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 1);
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(LTP_USR_UID2);
+		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
+		TST_EXP_FAIL(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777), EACCES);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 2);
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 2);
+	SAFE_CHMOD(DIR, 0020 | S_ISVTX);
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(LTP_USR_UID2);
+		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
+		TST_EXP_FAIL(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777), EACCES);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+	unlink(CONCAT(DIR, TEST_FIFO));
+}
+
+static void setup(void)
+{
+	umask(0);
+	SAFE_MKDIR(DIR, 0777 | S_ISVTX);
+	dir_fd = SAFE_OPEN(DIR, O_DIRECTORY);
+}
+
+static void cleanup(void)
+{
+	SAFE_CLOSE(dir_fd);
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.cleanup = cleanup,
+	.needs_root = 1,
+	.test_all = run,
+	.needs_tmpdir = 1,
+	.forks_child = 1,
+	.save_restore = (const struct tst_path_val[]) {
+		{PROTECTED_REGULAR, NULL, TST_SR_TCONF},
+		{PROTECTED_FIFOS, NULL, TST_SR_TCONF},
+		{}
+	},
+};
-- 
2.35.3


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH v3] open15: allow restricted O_CREAT of FIFOs and regular files

[Andrea Cervesato via ltp]

Hi Wei,

If we want to merge this patch, we need to do a couple of things more.
The open15 is now taken by an another test, so we need to move it to open16.
Also we don't have a nice git commit message describing what's the 
purpose of the test.

On 6/3/24 14:55, Wei Gao via ltp wrote:
> Fix: #574
>
> Signed-off-by: Wei Gao <wegao@suse.com>
> ---
>   runtest/syscalls                          |   1 +
>   testcases/kernel/syscalls/open/.gitignore |   1 +
>   testcases/kernel/syscalls/open/open15.c   | 125 ++++++++++++++++++++++
>   3 files changed, 127 insertions(+)
>   create mode 100644 testcases/kernel/syscalls/open/open15.c
>
> diff --git a/runtest/syscalls b/runtest/syscalls
> index 4f1ee1f34..4152e1e5f 100644
> --- a/runtest/syscalls
> +++ b/runtest/syscalls
> @@ -935,6 +935,7 @@ open11 open11
>   open12 open12
>   open13 open13
>   open14 open14
> +open15 open15
>   
>   openat01 openat01
>   openat02 openat02
> diff --git a/testcases/kernel/syscalls/open/.gitignore b/testcases/kernel/syscalls/open/.gitignore
> index 001d874d6..af5997572 100644
> --- a/testcases/kernel/syscalls/open/.gitignore
> +++ b/testcases/kernel/syscalls/open/.gitignore
> @@ -12,3 +12,4 @@
>   /open12_child
>   /open13
>   /open14
> +/open15
> diff --git a/testcases/kernel/syscalls/open/open15.c b/testcases/kernel/syscalls/open/open15.c
> new file mode 100644
> index 000000000..de5325e01
> --- /dev/null
> +++ b/testcases/kernel/syscalls/open/open15.c
> @@ -0,0 +1,125 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2023 Wei Gao <wegao@suse.com>
> + */
> +
> +/*\
> + * [Description]
Not needed anymore.
> + *
> + * Verify disallows open of FIFOs or regular files not owned by the user in world
> + * writable sticky directories
> + *
> + * commit 30aba6656f61ed44cba445a3c0d38b296fa9e8f5
> + * Author: Salvatore Mesoraca <s.mesoraca16@gmail.com>
> + * Date:   Thu Aug 23 17:00:35 2018 -0700
> + *     namei: allow restricted O_CREAT of FIFOs and regular files
we should update .tags instead of copying commit message here.
> + */
> +
> +#include <pwd.h>
> +#include <stdlib.h>
> +#include "tst_test.h"
> +#include "tst_safe_file_at.h"
> +
> +#define  FILENAME  "setuid04_testfile"
> +#define  DIR "ltp_tmp_check1"
> +#define  TEST_FILE "test_file_1"
> +#define  TEST_FIFO "test_fifo_1"
> +#define  LTP_USR_UID1 1000
> +#define  LTP_USR_UID2 1001
> +#define  CONCAT(dir, filename) dir "/" filename
> +#define  PROTECTED_REGULAR "/proc/sys/fs/protected_regular"
> +#define  PROTECTED_FIFOS "/proc/sys/fs/protected_fifos"
> +
> +static int dir_fd;
> +
> +static void run(void)
> +{
> +	int pid;
> +
> +	SAFE_CHMOD(DIR, 0777 | S_ISVTX);
> +	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 0);
> +	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 0);
> +
> +	if (!SAFE_FORK()) {
> +		SAFE_SETUID(LTP_USR_UID1);
> +
> +		int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
> +
> +		SAFE_CLOSE(fd);
> +
> +		SAFE_MKFIFO(CONCAT(DIR, TEST_FIFO), 0777);
> +
> +		exit(0);
> +	}
> +
> +	tst_reap_children();
> +
> +	if (!SAFE_FORK()) {
> +		SAFE_SETUID(LTP_USR_UID2);
> +
> +		int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
> +
> +		SAFE_CLOSE(fd);
> +
> +		fd = TST_EXP_FD(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777));
> +		SAFE_CLOSE(fd);
> +
> +		exit(0);
> +	}
> +
> +	tst_reap_children();
> +
> +	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 1);
> +	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 1);
> +
> +	if (!SAFE_FORK()) {
> +		SAFE_SETUID(LTP_USR_UID2);
> +		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
> +		TST_EXP_FAIL(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777), EACCES);
> +
> +		exit(0);
> +	}
> +
> +	tst_reap_children();
> +
> +	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 2);
> +	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 2);
> +	SAFE_CHMOD(DIR, 0020 | S_ISVTX);
> +
> +	if (!SAFE_FORK()) {
> +		SAFE_SETUID(LTP_USR_UID2);
> +		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
> +		TST_EXP_FAIL(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777), EACCES);
> +
> +		exit(0);
> +	}
> +
> +	tst_reap_children();
> +	unlink(CONCAT(DIR, TEST_FIFO));
SAFE_UNLINK()
> +}
> +
> +static void setup(void)
> +{
> +	umask(0);
> +	SAFE_MKDIR(DIR, 0777 | S_ISVTX);
> +	dir_fd = SAFE_OPEN(DIR, O_DIRECTORY);
> +}
> +
> +static void cleanup(void)
> +{
> +	SAFE_CLOSE(dir_fd);

if (dir_fd != -1)
     SAFE_CLOSE(dir_fd);

> +}
> +
> +static struct tst_test test = {
> +	.setup = setup,
> +	.cleanup = cleanup,
> +	.needs_root = 1,
> +	.test_all = run,
> +	.needs_tmpdir = 1,
> +	.forks_child = 1,
> +	.save_restore = (const struct tst_path_val[]) {
> +		{PROTECTED_REGULAR, NULL, TST_SR_TCONF},
> +		{PROTECTED_FIFOS, NULL, TST_SR_TCONF},
> +		{}
> +	},
.tags is missing.
> +};
Andrea

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v4] open16: allow restricted O_CREAT of FIFOs and regular files

[Wei Gao via ltp]

Signed-off-by: Wei Gao <wegao@suse.com>

This commit adds test cases to verify the security restrictions for opening
FIFOs and regular files in world-writable sticky directories.

Signed-off-by: Wei Gao <wegao@suse.com>
---
 runtest/syscalls                          |   1 +
 testcases/kernel/syscalls/open/.gitignore |   1 +
 testcases/kernel/syscalls/open/open16.c   | 121 ++++++++++++++++++++++
 3 files changed, 123 insertions(+)
 create mode 100644 testcases/kernel/syscalls/open/open16.c

diff --git a/runtest/syscalls b/runtest/syscalls
index 839c23d0a..7a1a64c01 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -974,6 +974,7 @@ open12 open12
 open13 open13
 open14 open14
 open15 open15
+open16 open16
 
 openat01 openat01
 openat02 openat02
diff --git a/testcases/kernel/syscalls/open/.gitignore b/testcases/kernel/syscalls/open/.gitignore
index af5997572..d2cacc02e 100644
--- a/testcases/kernel/syscalls/open/.gitignore
+++ b/testcases/kernel/syscalls/open/.gitignore
@@ -13,3 +13,4 @@
 /open13
 /open14
 /open15
+/open16
diff --git a/testcases/kernel/syscalls/open/open16.c b/testcases/kernel/syscalls/open/open16.c
new file mode 100644
index 000000000..709c5c87f
--- /dev/null
+++ b/testcases/kernel/syscalls/open/open16.c
@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2023 Wei Gao <wegao@suse.com>
+ */
+
+/*\
+ * Verify disallows open of FIFOs or regular files not owned by the user in world
+ * writable sticky directories
+ */
+
+#include <pwd.h>
+#include <stdlib.h>
+#include "tst_test.h"
+#include "tst_safe_file_at.h"
+
+#define  FILENAME  "setuid04_testfile"
+#define  DIR "ltp_tmp_check1"
+#define  TEST_FILE "test_file_1"
+#define  TEST_FIFO "test_fifo_1"
+#define  LTP_USR_UID1 1000
+#define  LTP_USR_UID2 1001
+#define  CONCAT(dir, filename) dir "/" filename
+#define  PROTECTED_REGULAR "/proc/sys/fs/protected_regular"
+#define  PROTECTED_FIFOS "/proc/sys/fs/protected_fifos"
+
+static int dir_fd;
+
+static void run(void)
+{
+	SAFE_CHMOD(DIR, 0777 | S_ISVTX);
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 0);
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 0);
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(LTP_USR_UID1);
+
+		int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
+
+		SAFE_CLOSE(fd);
+
+		SAFE_MKFIFO(CONCAT(DIR, TEST_FIFO), 0777);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(LTP_USR_UID2);
+
+		int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
+
+		SAFE_CLOSE(fd);
+
+		fd = TST_EXP_FD(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777));
+		SAFE_CLOSE(fd);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 1);
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 1);
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(LTP_USR_UID2);
+		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
+		TST_EXP_FAIL(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777), EACCES);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 2);
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 2);
+	SAFE_CHMOD(DIR, 0020 | S_ISVTX);
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(LTP_USR_UID2);
+		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
+		TST_EXP_FAIL(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777), EACCES);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+	SAFE_UNLINK(CONCAT(DIR, TEST_FIFO));
+}
+
+static void setup(void)
+{
+	umask(0);
+	SAFE_MKDIR(DIR, 0777 | S_ISVTX);
+	dir_fd = SAFE_OPEN(DIR, O_DIRECTORY);
+}
+
+static void cleanup(void)
+{
+	if (dir_fd != -1)
+		SAFE_CLOSE(dir_fd);
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.cleanup = cleanup,
+	.needs_root = 1,
+	.test_all = run,
+	.needs_tmpdir = 1,
+	.forks_child = 1,
+	.save_restore = (const struct tst_path_val[]) {
+		{PROTECTED_REGULAR, NULL, TST_SR_TCONF},
+		{PROTECTED_FIFOS, NULL, TST_SR_TCONF},
+		{}
+	},
+	.tags = (const struct tst_tag[]) {
+		{"linux-git", "30aba6656f61ed44cba445a3c0d38b296fa9e8f5"},
+		{}
+	}
+};
-- 
2.35.3


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH v4] open16: allow restricted O_CREAT of FIFOs and regular files

[Cyril Hrubis]

Hi!
> +/*\
> + * Verify disallows open of FIFOs or regular files not owned by the user in world
> + * writable sticky directories
> + */
> +
> +#include <pwd.h>
> +#include <stdlib.h>
> +#include "tst_test.h"
> +#include "tst_safe_file_at.h"
> +
> +#define  FILENAME  "setuid04_testfile"
> +#define  DIR "ltp_tmp_check1"
> +#define  TEST_FILE "test_file_1"
> +#define  TEST_FIFO "test_fifo_1"
> +#define  LTP_USR_UID1 1000
> +#define  LTP_USR_UID2 1001
> +#define  CONCAT(dir, filename) dir "/" filename
> +#define  PROTECTED_REGULAR "/proc/sys/fs/protected_regular"
> +#define  PROTECTED_FIFOS "/proc/sys/fs/protected_fifos"
           ^
	   Just a single space?

> +
> +static int dir_fd;
> +
> +static void run(void)
> +{
> +	SAFE_CHMOD(DIR, 0777 | S_ISVTX);



> +	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 0);
> +	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 0);

Huh, why not just SAFE_FILE_PRINTF(PROTECTED_FIFOS, "0") ?

> +	if (!SAFE_FORK()) {
> +		SAFE_SETUID(LTP_USR_UID1);
> +
> +		int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
> +
> +		SAFE_CLOSE(fd);
                ^
		if (TST_PASS)
			SAFE_CLOSE(TST_RET);

Also this seems like a setup phase, so we should probably use just
SAFE_OPEN() instead of the TST_EXP_FD() at this point.

> +		SAFE_MKFIFO(CONCAT(DIR, TEST_FIFO), 0777);
                                  ^
We usually do this as:

#define TEST_FIFO_PATH DIR "/" TEST_FIFO

And use the TEST_FIFO_PATH instead.


Or we can just do SAFE_CHDIR(DIR) after the fork and use just the file
names.

> +		exit(0);
> +	}
> +
> +	tst_reap_children();
> +
> +	if (!SAFE_FORK()) {
> +		SAFE_SETUID(LTP_USR_UID2);
> +
> +		int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
> +
> +		SAFE_CLOSE(fd);

Here as well:

		if (TST_PASS)
			SAFE_CLOSE(TST_RET)

> +		fd = TST_EXP_FD(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777));
> +		SAFE_CLOSE(fd);

And here as well.

> +		exit(0);
> +	}
> +
> +	tst_reap_children();
> +
> +	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 1);
> +	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 1);

Here as well why the %d?

> +	if (!SAFE_FORK()) {
> +		SAFE_SETUID(LTP_USR_UID2);
> +		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
> +		TST_EXP_FAIL(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777), EACCES);
> +
> +		exit(0);
> +	}
> +
> +	tst_reap_children();
> +
> +	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%d", 2);
> +	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%d", 2);

And here as well.

> +	SAFE_CHMOD(DIR, 0020 | S_ISVTX);
> +
> +	if (!SAFE_FORK()) {
> +		SAFE_SETUID(LTP_USR_UID2);
> +		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
> +		TST_EXP_FAIL(open(CONCAT(DIR, TEST_FIFO), O_RDWR | O_CREAT, 0777), EACCES);
> +
> +		exit(0);
> +	}
> +
> +	tst_reap_children();
> +	SAFE_UNLINK(CONCAT(DIR, TEST_FIFO));
> +}
> +
> +static void setup(void)
> +{
> +	umask(0);
> +	SAFE_MKDIR(DIR, 0777 | S_ISVTX);
> +	dir_fd = SAFE_OPEN(DIR, O_DIRECTORY);
> +}
> +
> +static void cleanup(void)
> +{
> +	if (dir_fd != -1)
> +		SAFE_CLOSE(dir_fd);
> +}
> +
> +static struct tst_test test = {
> +	.setup = setup,
> +	.cleanup = cleanup,
> +	.needs_root = 1,
> +	.test_all = run,
> +	.needs_tmpdir = 1,
> +	.forks_child = 1,
> +	.save_restore = (const struct tst_path_val[]) {
> +		{PROTECTED_REGULAR, NULL, TST_SR_TCONF},
> +		{PROTECTED_FIFOS, NULL, TST_SR_TCONF},
> +		{}
> +	},
> +	.tags = (const struct tst_tag[]) {
> +		{"linux-git", "30aba6656f61ed44cba445a3c0d38b296fa9e8f5"},
                               ^
			       We usually shorten these to just first 12
			       characters.

> +		{}
> +	}
> +};
> -- 
> 2.35.3
> 
> 
> -- 
> Mailing list info: https://lists.linux.it/listinfo/ltp

-- 
Cyril Hrubis
chrubis@suse.cz

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v5] open16: allow restricted O_CREAT of FIFOs and regular files

[Wei Gao via ltp]

This commit adds test cases to verify the security restrictions for opening
FIFOs and regular files in world-writable sticky directories.

Signed-off-by: Wei Gao <wegao@suse.com>
---
 runtest/syscalls                          |   1 +
 testcases/kernel/syscalls/open/.gitignore |   1 +
 testcases/kernel/syscalls/open/open16.c   | 124 ++++++++++++++++++++++
 3 files changed, 126 insertions(+)
 create mode 100644 testcases/kernel/syscalls/open/open16.c

diff --git a/runtest/syscalls b/runtest/syscalls
index 3531c2a3c..0de9bfaef 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -984,6 +984,7 @@ open12 open12
 open13 open13
 open14 open14
 open15 open15
+open16 open16
 
 openat01 openat01
 openat02 openat02
diff --git a/testcases/kernel/syscalls/open/.gitignore b/testcases/kernel/syscalls/open/.gitignore
index af5997572..d2cacc02e 100644
--- a/testcases/kernel/syscalls/open/.gitignore
+++ b/testcases/kernel/syscalls/open/.gitignore
@@ -13,3 +13,4 @@
 /open13
 /open14
 /open15
+/open16
diff --git a/testcases/kernel/syscalls/open/open16.c b/testcases/kernel/syscalls/open/open16.c
new file mode 100644
index 000000000..6e01dde26
--- /dev/null
+++ b/testcases/kernel/syscalls/open/open16.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2023 Wei Gao <wegao@suse.com>
+ */
+
+/*\
+ * Verify disallows open of FIFOs or regular files not owned by the user in world
+ * writable sticky directories
+ */
+
+#include <pwd.h>
+#include <stdlib.h>
+#include "tst_test.h"
+#include "tst_safe_file_at.h"
+
+#define FILENAME  "setuid04_testfile"
+#define DIR "ltp_tmp_check1"
+#define TEST_FILE "test_file_1"
+#define TEST_FIFO "test_fifo_1"
+#define LTP_USR_UID1 1000
+#define LTP_USR_UID2 1001
+#define PROTECTED_REGULAR "/proc/sys/fs/protected_regular"
+#define PROTECTED_FIFOS "/proc/sys/fs/protected_fifos"
+#define TEST_FIFO_PATH DIR "/" TEST_FIFO
+
+static int dir_fd;
+
+static void run(void)
+{
+	SAFE_CHMOD(DIR, 0777 | S_ISVTX);
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "0");
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "0");
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(LTP_USR_UID1);
+
+		int fd = SAFE_OPENAT(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777);
+
+		SAFE_CLOSE(fd);
+
+		SAFE_MKFIFO(TEST_FIFO_PATH, 0777);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(LTP_USR_UID2);
+
+		int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
+
+		if (TST_PASS)
+			SAFE_CLOSE(fd);
+
+		fd = TST_EXP_FD(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777));
+
+		if (TST_PASS)
+			SAFE_CLOSE(fd);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "1");
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "1");
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(LTP_USR_UID2);
+		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
+		TST_EXP_FAIL(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777), EACCES);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "2");
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "2");
+	SAFE_CHMOD(DIR, 0020 | S_ISVTX);
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(LTP_USR_UID2);
+		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
+		TST_EXP_FAIL(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777), EACCES);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+	SAFE_UNLINK(TEST_FIFO_PATH);
+}
+
+static void setup(void)
+{
+	umask(0);
+	SAFE_MKDIR(DIR, 0777 | S_ISVTX);
+	dir_fd = SAFE_OPEN(DIR, O_DIRECTORY);
+}
+
+static void cleanup(void)
+{
+	if (dir_fd != -1)
+		SAFE_CLOSE(dir_fd);
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.cleanup = cleanup,
+	.needs_root = 1,
+	.test_all = run,
+	.needs_tmpdir = 1,
+	.forks_child = 1,
+	.save_restore = (const struct tst_path_val[]) {
+		{PROTECTED_REGULAR, NULL, TST_SR_TCONF},
+		{PROTECTED_FIFOS, NULL, TST_SR_TCONF},
+		{}
+	},
+	.tags = (const struct tst_tag[]) {
+		{"linux-git", "30aba6656f61"},
+		{}
+	}
+};
-- 
2.49.0


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH v5] open16: allow restricted O_CREAT of FIFOs and regular files

[Andrea Cervesato via ltp]

Hi!

On Wed Jul 23, 2025 at 5:46 PM CEST, Wei Gao via ltp wrote:
> This commit adds test cases to verify the security restrictions for opening
> FIFOs and regular files in world-writable sticky directories.
>
> Signed-off-by: Wei Gao <wegao@suse.com>
> ---
>  runtest/syscalls                          |   1 +
>  testcases/kernel/syscalls/open/.gitignore |   1 +
>  testcases/kernel/syscalls/open/open16.c   | 124 ++++++++++++++++++++++
>  3 files changed, 126 insertions(+)
>  create mode 100644 testcases/kernel/syscalls/open/open16.c
>
> diff --git a/runtest/syscalls b/runtest/syscalls
> index 3531c2a3c..0de9bfaef 100644
> --- a/runtest/syscalls
> +++ b/runtest/syscalls
> @@ -984,6 +984,7 @@ open12 open12
>  open13 open13
>  open14 open14
>  open15 open15
> +open16 open16
>  
>  openat01 openat01
>  openat02 openat02
> diff --git a/testcases/kernel/syscalls/open/.gitignore b/testcases/kernel/syscalls/open/.gitignore
> index af5997572..d2cacc02e 100644
> --- a/testcases/kernel/syscalls/open/.gitignore
> +++ b/testcases/kernel/syscalls/open/.gitignore
> @@ -13,3 +13,4 @@
>  /open13
>  /open14
>  /open15
> +/open16
> diff --git a/testcases/kernel/syscalls/open/open16.c b/testcases/kernel/syscalls/open/open16.c
> new file mode 100644
> index 000000000..6e01dde26
> --- /dev/null
> +++ b/testcases/kernel/syscalls/open/open16.c
> @@ -0,0 +1,124 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2023 Wei Gao <wegao@suse.com>
> + */
> +
> +/*\
> + * Verify disallows open of FIFOs or regular files not owned by the user in world
> + * writable sticky directories
> + */
> +
> +#include <pwd.h>
> +#include <stdlib.h>
> +#include "tst_test.h"
> +#include "tst_safe_file_at.h"
> +
> +#define FILENAME  "setuid04_testfile"

Never used.

> +#define DIR "ltp_tmp_check1"
> +#define TEST_FILE "test_file_1"
> +#define TEST_FIFO "test_fifo_1"
> +#define LTP_USR_UID1 1000
> +#define LTP_USR_UID2 1001

If target is to have a UID that doesn't belong to the current user,
we can just have:

  pw = SAFE_GETPWNAM("nobody");

and use the provided UID.

> +#define PROTECTED_REGULAR "/proc/sys/fs/protected_regular"
> +#define PROTECTED_FIFOS "/proc/sys/fs/protected_fifos"
> +#define TEST_FIFO_PATH DIR "/" TEST_FIFO
> +
> +static int dir_fd;

Not initialized to -1.

> +
> +static void run(void)
> +{
> +	SAFE_CHMOD(DIR, 0777 | S_ISVTX);
> +	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "0");
> +	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "0");
> +
> +	if (!SAFE_FORK()) {
> +		SAFE_SETUID(LTP_USR_UID1);
> +
> +		int fd = SAFE_OPENAT(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777);
> +
> +		SAFE_CLOSE(fd);
> +
> +		SAFE_MKFIFO(TEST_FIFO_PATH, 0777);
> +
> +		exit(0);
> +	}
> +
> +	tst_reap_children();
> +
> +	if (!SAFE_FORK()) {
> +		SAFE_SETUID(LTP_USR_UID2);
> +
> +		int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
> +
> +		if (TST_PASS)
> +			SAFE_CLOSE(fd);
> +
> +		fd = TST_EXP_FD(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777));
> +
> +		if (TST_PASS)
> +			SAFE_CLOSE(fd);
> +
> +		exit(0);
> +	}
> +
> +	tst_reap_children();
> +
> +	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "1");
> +	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "1");
> +
> +	if (!SAFE_FORK()) {
> +		SAFE_SETUID(LTP_USR_UID2);
> +		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
> +		TST_EXP_FAIL(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777), EACCES);
> +
> +		exit(0);
> +	}
> +
> +	tst_reap_children();
> +
> +	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "2");
> +	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "2");
> +	SAFE_CHMOD(DIR, 0020 | S_ISVTX);
> +
> +	if (!SAFE_FORK()) {
> +		SAFE_SETUID(LTP_USR_UID2);
> +		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
> +		TST_EXP_FAIL(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777), EACCES);
> +
> +		exit(0);
> +	}
> +
> +	tst_reap_children();
> +	SAFE_UNLINK(TEST_FIFO_PATH);
> +}
> +
> +static void setup(void)
> +{
> +	umask(0);
> +	SAFE_MKDIR(DIR, 0777 | S_ISVTX);
> +	dir_fd = SAFE_OPEN(DIR, O_DIRECTORY);
> +}
> +
> +static void cleanup(void)
> +{
> +	if (dir_fd != -1)
> +		SAFE_CLOSE(dir_fd);
> +}
> +
> +static struct tst_test test = {
> +	.setup = setup,
> +	.cleanup = cleanup,
> +	.needs_root = 1,
> +	.test_all = run,
> +	.needs_tmpdir = 1,
> +	.forks_child = 1,
> +	.save_restore = (const struct tst_path_val[]) {
> +		{PROTECTED_REGULAR, NULL, TST_SR_TCONF},
> +		{PROTECTED_FIFOS, NULL, TST_SR_TCONF},
> +		{}
> +	},
> +	.tags = (const struct tst_tag[]) {
> +		{"linux-git", "30aba6656f61"},
> +		{}
> +	}
> +};


-- 
Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v6 0/2] open16: allow restricted O_CREAT of FIFOs and regular files

[Wei Gao via ltp]

Wei Gao (2):
  lib: New library function tst_get_free_uid
  open16: allow restricted O_CREAT of FIFOs and regular files

v5->v6:
- Remove unused FILENAME
- Initialize dir_fd to -1
- Use tst_get_free_uid() dynamically find unused UIDs instead of fixed
  uids

 include/tst_uid.h                         |   7 +-
 lib/tst_uid.c                             |  26 +++++
 runtest/syscalls                          |   1 +
 testcases/kernel/syscalls/open/.gitignore |   1 +
 testcases/kernel/syscalls/open/open16.c   | 129 ++++++++++++++++++++++
 5 files changed, 162 insertions(+), 2 deletions(-)
 create mode 100644 testcases/kernel/syscalls/open/open16.c

-- 
2.52.0


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v6 1/2] lib: New library function tst_get_free_uid

[Wei Gao via ltp]

Signed-off-by: Wei Gao <wegao@suse.com>
---
 include/tst_uid.h |  7 +++++--
 lib/tst_uid.c     | 26 ++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/include/tst_uid.h b/include/tst_uid.h
index 2237ddcbf..394cb3edc 100644
--- a/include/tst_uid.h
+++ b/include/tst_uid.h
@@ -8,10 +8,13 @@
 #include <sys/types.h>
 
 /*
- * Find unassigned gid. The skip argument can be used to ignore e.g. the main
+ * Find unassigned uid/gid. The skip argument can be used to ignore e.g. the main
  * group of a specific user in case it's not listed in the group file. If you
- * do not need to skip any specific gid, simply set it to 0.
+ * do not need to skip any specific id, simply set it to 0.
  */
+uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip);
+#define tst_get_free_uid(skip) tst_get_free_uid_(__FILE__, __LINE__, (skip))
+
 gid_t tst_get_free_gid_(const char *file, const int lineno, gid_t skip);
 #define tst_get_free_gid(skip) tst_get_free_gid_(__FILE__, __LINE__, (skip))
 
diff --git a/lib/tst_uid.c b/lib/tst_uid.c
index af4ef8cf7..deff17085 100644
--- a/lib/tst_uid.c
+++ b/lib/tst_uid.c
@@ -5,6 +5,7 @@
 
 #include <sys/types.h>
 #include <grp.h>
+#include <pwd.h>
 #include <errno.h>
 
 #define TST_NO_DEFAULT_MAIN
@@ -12,6 +13,31 @@
 #include "tst_uid.h"
 
 #define MAX_GID 32767
+#define MAX_UID 32767
+
+uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip)
+{
+	uid_t ret;
+
+	errno = 0;
+
+	for (ret = 1; ret < MAX_UID; ret++) {
+		if (ret == skip || getpwuid(ret))
+			continue;
+
+		if (errno == 0 || errno == ENOENT || errno == ESRCH) {
+			tst_res_(file, lineno, TINFO | TERRNO,
+				"Found unused UID %d", (int)ret);
+			return ret;
+		}
+
+		tst_brk_(file, lineno, TBROK|TERRNO, "User ID lookup failed");
+		return (uid_t)-1;
+	}
+
+	tst_brk_(file, lineno, TBROK, "No free user ID found");
+	return (uid_t)-1;
+}
 
 gid_t tst_get_free_gid_(const char *file, const int lineno, gid_t skip)
 {
-- 
2.52.0


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] lib: New library function tst_get_free_uid

[linuxtestproject.agent]

Hi Wei,

--- [PATCH 1/2] ---

On Wed, 15 Apr 2026 06:07:16 +0000, Wei Gao wrote:
> [PATCH 1/2] lib: New library function tst_get_free_uid

The commit body is empty. Add at least one sentence explaining why
this helper is needed — e.g. that open16 requires two distinct
unprivileged UIDs and that this extends the existing tst_get_free_gid
pattern to UIDs.

--- [PATCH 2/2] ---

On Wed, 15 Apr 2026 06:07:17 +0000, Wei Gao wrote:
> [PATCH 2/2] open16: allow restricted O_CREAT of FIFOs and regular files

Same issue — no commit body. Describe what kernel feature is under
test (protected_regular/protected_fifos, kernel commit 30aba6656f61)
and why a dedicated test was needed.

> +/*\
> + * Verify disallows open of FIFOs or regular files not owned by the user in world
> + * writable sticky directories
> + */

Incomplete. The test also verifies the positive case (protection=0
allows access) and level 2 protection (group-writable sticky
directories via SAFE_CHMOD(DIR, 0020|S_ISVTX)). Update the doc
comment to cover all three scenarios.

---
Note:

Our agent completed the review of the patch. The full review can be
found at: https://github.com/linux-test-project/ltp-agent/actions/runs/24442661607

The agent can sometimes produce false positives although often its
findings are genuine. If you find issues with the review, please
comment this email or ignore the suggestions.

Regards,
LTP AI Reviewer

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v6 2/2] open16: allow restricted O_CREAT of FIFOs and regular files

[Wei Gao via ltp]

Signed-off-by: Wei Gao <wegao@suse.com>
---
 runtest/syscalls                          |   1 +
 testcases/kernel/syscalls/open/.gitignore |   1 +
 testcases/kernel/syscalls/open/open16.c   | 129 ++++++++++++++++++++++
 3 files changed, 131 insertions(+)
 create mode 100644 testcases/kernel/syscalls/open/open16.c

diff --git a/runtest/syscalls b/runtest/syscalls
index d72fceb5e..c14ebb3a0 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -1005,6 +1005,7 @@ open12 open12
 open13 open13
 open14 open14
 open15 open15
+open16 open16
 
 openat01 openat01
 openat02 openat02
diff --git a/testcases/kernel/syscalls/open/.gitignore b/testcases/kernel/syscalls/open/.gitignore
index af5997572..d2cacc02e 100644
--- a/testcases/kernel/syscalls/open/.gitignore
+++ b/testcases/kernel/syscalls/open/.gitignore
@@ -13,3 +13,4 @@
 /open13
 /open14
 /open15
+/open16
diff --git a/testcases/kernel/syscalls/open/open16.c b/testcases/kernel/syscalls/open/open16.c
new file mode 100644
index 000000000..9ec6515e7
--- /dev/null
+++ b/testcases/kernel/syscalls/open/open16.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2026 Wei Gao <wegao@suse.com>
+ */
+
+/*\
+ * Verify disallows open of FIFOs or regular files not owned by the user in world
+ * writable sticky directories
+ */
+
+#include <pwd.h>
+#include <stdlib.h>
+#include "tst_test.h"
+#include "tst_safe_file_at.h"
+#include "tst_uid.h"
+
+#define DIR "ltp_tmp_check1"
+#define TEST_FILE "test_file_1"
+#define TEST_FIFO "test_fifo_1"
+#define PROTECTED_REGULAR "/proc/sys/fs/protected_regular"
+#define PROTECTED_FIFOS "/proc/sys/fs/protected_fifos"
+#define TEST_FIFO_PATH DIR "/" TEST_FIFO
+
+static int dir_fd = -1;
+static uid_t uid1, uid2;
+
+static void run(void)
+{
+	SAFE_CHMOD(DIR, 0777 | S_ISVTX);
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "0");
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "0");
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(uid1);
+
+		int fd = SAFE_OPENAT(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777);
+
+		SAFE_CLOSE(fd);
+
+		SAFE_MKFIFO(TEST_FIFO_PATH, 0777);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(uid2);
+
+		int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
+
+		if (TST_PASS)
+			SAFE_CLOSE(fd);
+
+		fd = TST_EXP_FD(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777));
+
+		if (TST_PASS)
+			SAFE_CLOSE(fd);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "1");
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "1");
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(uid2);
+		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
+		TST_EXP_FAIL(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777), EACCES);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "2");
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "2");
+	SAFE_CHMOD(DIR, 0020 | S_ISVTX);
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(uid2);
+		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
+		TST_EXP_FAIL(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777), EACCES);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+	SAFE_UNLINK(TEST_FIFO_PATH);
+}
+
+static void setup(void)
+{
+	struct passwd *pw;
+
+	pw = SAFE_GETPWNAM("nobody");
+	uid1 = pw->pw_uid;
+	uid2 = tst_get_free_uid(uid1);
+
+	umask(0);
+	SAFE_MKDIR(DIR, 0777 | S_ISVTX);
+	dir_fd = SAFE_OPEN(DIR, O_DIRECTORY);
+}
+
+static void cleanup(void)
+{
+	if (dir_fd != -1)
+		SAFE_CLOSE(dir_fd);
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.cleanup = cleanup,
+	.needs_root = 1,
+	.test_all = run,
+	.needs_tmpdir = 1,
+	.forks_child = 1,
+	.save_restore = (const struct tst_path_val[]) {
+		{PROTECTED_REGULAR, NULL, TST_SR_TCONF},
+		{PROTECTED_FIFOS, NULL, TST_SR_TCONF},
+		{}
+	},
+	.tags = (const struct tst_tag[]) {
+		{"linux-git", "30aba6656f61"},
+		{}
+	}
+};
-- 
2.52.0


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v6 0/2] open16: allow restricted O_CREAT of FIFOs and regular files

[Wei Gao via ltp]

Wei Gao (2):
  lib: New library function tst_get_free_uid
  open16: allow restricted O_CREAT of FIFOs and regular files

v6->v7:
- Add commit body
- Update test description

 include/tst_uid.h                         |   7 +-
 lib/tst_uid.c                             |  26 +++++
 runtest/syscalls                          |   1 +
 testcases/kernel/syscalls/open/.gitignore |   1 +
 testcases/kernel/syscalls/open/open16.c   | 132 ++++++++++++++++++++++
 5 files changed, 165 insertions(+), 2 deletions(-)
 create mode 100644 testcases/kernel/syscalls/open/open16.c

-- 
2.52.0


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v7 1/2] lib: New library function tst_get_free_uid

[Wei Gao via ltp]

Add tst_get_free_uid() to dynamically find unused UIDs for tests.

Signed-off-by: Wei Gao <wegao@suse.com>
---
 include/tst_uid.h |  7 +++++--
 lib/tst_uid.c     | 26 ++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/include/tst_uid.h b/include/tst_uid.h
index 2237ddcbf..394cb3edc 100644
--- a/include/tst_uid.h
+++ b/include/tst_uid.h
@@ -8,10 +8,13 @@
 #include <sys/types.h>
 
 /*
- * Find unassigned gid. The skip argument can be used to ignore e.g. the main
+ * Find unassigned uid/gid. The skip argument can be used to ignore e.g. the main
  * group of a specific user in case it's not listed in the group file. If you
- * do not need to skip any specific gid, simply set it to 0.
+ * do not need to skip any specific id, simply set it to 0.
  */
+uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip);
+#define tst_get_free_uid(skip) tst_get_free_uid_(__FILE__, __LINE__, (skip))
+
 gid_t tst_get_free_gid_(const char *file, const int lineno, gid_t skip);
 #define tst_get_free_gid(skip) tst_get_free_gid_(__FILE__, __LINE__, (skip))
 
diff --git a/lib/tst_uid.c b/lib/tst_uid.c
index af4ef8cf7..deff17085 100644
--- a/lib/tst_uid.c
+++ b/lib/tst_uid.c
@@ -5,6 +5,7 @@
 
 #include <sys/types.h>
 #include <grp.h>
+#include <pwd.h>
 #include <errno.h>
 
 #define TST_NO_DEFAULT_MAIN
@@ -12,6 +13,31 @@
 #include "tst_uid.h"
 
 #define MAX_GID 32767
+#define MAX_UID 32767
+
+uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip)
+{
+	uid_t ret;
+
+	errno = 0;
+
+	for (ret = 1; ret < MAX_UID; ret++) {
+		if (ret == skip || getpwuid(ret))
+			continue;
+
+		if (errno == 0 || errno == ENOENT || errno == ESRCH) {
+			tst_res_(file, lineno, TINFO | TERRNO,
+				"Found unused UID %d", (int)ret);
+			return ret;
+		}
+
+		tst_brk_(file, lineno, TBROK|TERRNO, "User ID lookup failed");
+		return (uid_t)-1;
+	}
+
+	tst_brk_(file, lineno, TBROK, "No free user ID found");
+	return (uid_t)-1;
+}
 
 gid_t tst_get_free_gid_(const char *file, const int lineno, gid_t skip)
 {
-- 
2.52.0


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] lib: New library function tst_get_free_uid

[linuxtestproject.agent]

Hi Wei,

On Wed, 15 Apr 2026, Wei Gao wrote:
> open16: allow restricted O_CREAT of FIFOs and regular files

--- [PATCH 2/2] ---

On Wed, 15 Apr 2026, Wei Gao wrote:
> open16: allow restricted O_CREAT of FIFOs and regular files

> +	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "2");
> +	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "2");
> +	SAFE_CHMOD(DIR, 0020 | S_ISVTX);
> +
> +	if (!SAFE_FORK()) {
> +		SAFE_SETUID(uid2);
> +		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
> +		TST_EXP_FAIL(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777), EACCES);

uid2 is a free (unused) UID with no group memberships. With mode 0020|S_ISVTX
the "other" bits are 0, so the kernel's DAC check rejects openat/open before
reaching the protected_regular/protected_fifos logic in may_open(). EACCES
fires for the wrong reason.

For a valid level-2 test the directory needs group-execute and group-write
(e.g. 0770|S_ISVTX), and uid2 must be placed in the directory's owning group
so it can access the directory but is still blocked by the protection check.

---
Note:

Our agent completed the review of the patch. The full review can be
found at: <review_url>

The agent can sometimes produce false positives although often its
findings are genuine. If you find issues with the review, please
comment this email or ignore the suggestions.

Regards,
LTP AI Reviewer

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v8 0/2] open16: allow restricted O_CREAT of FIFOs and regular files

[Wei Gao via ltp]

Wei Gao (2):
  lib: New library function tst_get_free_uid
  open16: allow restricted O_CREAT of FIFOs and regular files

v7->v8
- Update comments of test cases
- Refactor test case with tcase array
- Set file mode to 0030 for level2 check
- TST_EXP_FAIL->TST_EXP_FAIL2

 include/tst_uid.h                         |   7 +-
 lib/tst_uid.c                             |  26 +++++
 runtest/syscalls                          |   1 +
 testcases/kernel/syscalls/open/.gitignore |   1 +
 testcases/kernel/syscalls/open/open16.c   | 128 ++++++++++++++++++++++
 5 files changed, 161 insertions(+), 2 deletions(-)
 create mode 100644 testcases/kernel/syscalls/open/open16.c

-- 
2.52.0


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v8 1/2] lib: New library function tst_get_free_uid

[Wei Gao via ltp]

Add tst_get_free_uid() to dynamically find unused UIDs for tests.

Signed-off-by: Wei Gao <wegao@suse.com>
---
 include/tst_uid.h |  7 +++++--
 lib/tst_uid.c     | 26 ++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/include/tst_uid.h b/include/tst_uid.h
index 2237ddcbf..394cb3edc 100644
--- a/include/tst_uid.h
+++ b/include/tst_uid.h
@@ -8,10 +8,13 @@
 #include <sys/types.h>
 
 /*
- * Find unassigned gid. The skip argument can be used to ignore e.g. the main
+ * Find unassigned uid/gid. The skip argument can be used to ignore e.g. the main
  * group of a specific user in case it's not listed in the group file. If you
- * do not need to skip any specific gid, simply set it to 0.
+ * do not need to skip any specific id, simply set it to 0.
  */
+uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip);
+#define tst_get_free_uid(skip) tst_get_free_uid_(__FILE__, __LINE__, (skip))
+
 gid_t tst_get_free_gid_(const char *file, const int lineno, gid_t skip);
 #define tst_get_free_gid(skip) tst_get_free_gid_(__FILE__, __LINE__, (skip))
 
diff --git a/lib/tst_uid.c b/lib/tst_uid.c
index af4ef8cf7..deff17085 100644
--- a/lib/tst_uid.c
+++ b/lib/tst_uid.c
@@ -5,6 +5,7 @@
 
 #include <sys/types.h>
 #include <grp.h>
+#include <pwd.h>
 #include <errno.h>
 
 #define TST_NO_DEFAULT_MAIN
@@ -12,6 +13,31 @@
 #include "tst_uid.h"
 
 #define MAX_GID 32767
+#define MAX_UID 32767
+
+uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip)
+{
+	uid_t ret;
+
+	errno = 0;
+
+	for (ret = 1; ret < MAX_UID; ret++) {
+		if (ret == skip || getpwuid(ret))
+			continue;
+
+		if (errno == 0 || errno == ENOENT || errno == ESRCH) {
+			tst_res_(file, lineno, TINFO | TERRNO,
+				"Found unused UID %d", (int)ret);
+			return ret;
+		}
+
+		tst_brk_(file, lineno, TBROK|TERRNO, "User ID lookup failed");
+		return (uid_t)-1;
+	}
+
+	tst_brk_(file, lineno, TBROK, "No free user ID found");
+	return (uid_t)-1;
+}
 
 gid_t tst_get_free_gid_(const char *file, const int lineno, gid_t skip)
 {
-- 
2.52.0


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] lib: New library function tst_get_free_uid

[linuxtestproject.agent]

Hi Wei,

On Thu, 16 Apr 2026 00:55:23 +0000, Wei Gao via ltp wrote:
> [PATCH 2/2] open16: allow restricted O_CREAT of FIFOs and regular files
>
> This commit adds test cases to verify the security restrictions for opening
> FIFOs and regular files in world-writable sticky directories.

The body only describes what the test does, not why it is being added.
State the motivation explicitly, e.g. "Add LTP coverage for kernel commit
30aba6656f61 (Linux 4.19), which introduced protection against spoofing
attacks via O_CREAT of FIFOs and regular files in world-writable sticky
directories."

[...]

Regards,
LTP AI Reviewer

---
Note:

Our agent completed the review of the patch.

The agent can sometimes produce false positives although often its
findings are genuine. If you find issues with the review, please
comment this email or ignore the suggestions.

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] lib: New library function tst_get_free_uid

[Wei Gao via ltp]

On Thu, Apr 16, 2026 at 02:43:24AM +0000, linuxtestproject.agent@gmail.com wrote:
> Hi Wei,
> 
> On Thu, 16 Apr 2026 00:55:23 +0000, Wei Gao via ltp wrote:
> > [PATCH 2/2] open16: allow restricted O_CREAT of FIFOs and regular files
> >
> > This commit adds test cases to verify the security restrictions for opening
> > FIFOs and regular files in world-writable sticky directories.
> 
> The body only describes what the test does, not why it is being added.
> State the motivation explicitly, e.g. "Add LTP coverage for kernel commit
> 30aba6656f61 (Linux 4.19), which introduced protection against spoofing
> attacks via O_CREAT of FIFOs and regular files in world-writable sticky
> directories."
Patchset cover letter and the tags within the test code (which already reference
linux-git 30aba6656f61) clearly established the purpose
> 
> [...]
> 
> Regards,
> LTP AI Reviewer
> 
> ---
> Note:
> 
> Our agent completed the review of the patch.
> 
> The agent can sometimes produce false positives although often its
> findings are genuine. If you find issues with the review, please
> comment this email or ignore the suggestions.

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v8 2/2] open16: allow restricted O_CREAT of FIFOs and regular files

[Wei Gao via ltp]

This commit adds test cases to verify the security restrictions for opening
FIFOs and regular files in world-writable sticky directories.

Signed-off-by: Wei Gao <wegao@suse.com>
---
 runtest/syscalls                          |   1 +
 testcases/kernel/syscalls/open/.gitignore |   1 +
 testcases/kernel/syscalls/open/open16.c   | 128 ++++++++++++++++++++++
 3 files changed, 130 insertions(+)
 create mode 100644 testcases/kernel/syscalls/open/open16.c

diff --git a/runtest/syscalls b/runtest/syscalls
index d72fceb5e..c14ebb3a0 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -1005,6 +1005,7 @@ open12 open12
 open13 open13
 open14 open14
 open15 open15
+open16 open16
 
 openat01 openat01
 openat02 openat02
diff --git a/testcases/kernel/syscalls/open/.gitignore b/testcases/kernel/syscalls/open/.gitignore
index af5997572..d2cacc02e 100644
--- a/testcases/kernel/syscalls/open/.gitignore
+++ b/testcases/kernel/syscalls/open/.gitignore
@@ -13,3 +13,4 @@
 /open13
 /open14
 /open15
+/open16
diff --git a/testcases/kernel/syscalls/open/open16.c b/testcases/kernel/syscalls/open/open16.c
new file mode 100644
index 000000000..8ba2d9ec9
--- /dev/null
+++ b/testcases/kernel/syscalls/open/open16.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2026 Wei Gao <wegao@suse.com>
+ */
+
+/*\
+ * Verify restricted opening of FIFOs and regular files in sticky directories.
+ * This test covers the positive case where access is allowed when protection
+ * is disabled (level 0), and the negative cases where access is disallowed
+ * (EACCES) in world-writable (level 1) or group-writable (level 2) sticky
+ * directories when the file is not owned by the opener.
+ *
+ * This test requires root to modify /proc/sys/fs/protected_* sysctls and
+ * to manage file ownership and permissions in sticky directories.
+ */
+
+#include <pwd.h>
+#include <stdlib.h>
+#include "tst_test.h"
+#include "tst_safe_file_at.h"
+#include "tst_uid.h"
+
+#define DIR "ltp_tmp_check1"
+#define TEST_FILE "test_file_1"
+#define TEST_FIFO "test_fifo_1"
+#define PROTECTED_REGULAR "/proc/sys/fs/protected_regular"
+#define PROTECTED_FIFOS "/proc/sys/fs/protected_fifos"
+#define TEST_FIFO_PATH DIR "/" TEST_FIFO
+
+static int dir_fd = -1;
+static uid_t uid1, uid2;
+static gid_t gid1;
+
+static struct tcase {
+	char *level;
+	int exp_errno;
+} tcases[] = {
+	{"0", 0},
+	{"1", EACCES},
+	{"2", EACCES},
+};
+
+static void verify_open(unsigned int n)
+{
+	struct tcase *tc = &tcases[n];
+	pid_t pid;
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%s", tc->level);
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%s", tc->level);
+
+	if (n == 2) {
+		SAFE_CHOWN(DIR, -1, gid1);
+		SAFE_CHMOD(DIR, 0030 | S_ISVTX);
+	} else {
+		SAFE_CHOWN(DIR, 0, 0);
+		SAFE_CHMOD(DIR, 0777 | S_ISVTX);
+	}
+
+	pid = SAFE_FORK();
+	if (!pid) {
+		SAFE_SETGID(gid1);
+		SAFE_SETUID(uid2);
+
+		if (tc->exp_errno) {
+			TST_EXP_FAIL2(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777),
+				tc->exp_errno, "openat %s (Level %s)", TEST_FILE, tc->level);
+			TST_EXP_FAIL2(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777),
+				tc->exp_errno, "open %s (Level %s)", TEST_FIFO, tc->level);
+		} else {
+			int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
+			if (TST_PASS)
+				SAFE_CLOSE(fd);
+
+			fd = TST_EXP_FD(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777));
+			if (TST_PASS)
+				SAFE_CLOSE(fd);
+		}
+
+		exit(0);
+	}
+
+	SAFE_WAITPID(pid, NULL, 0);
+}
+
+static void setup(void)
+{
+	struct passwd *pw;
+
+	pw = SAFE_GETPWNAM("nobody");
+	uid1 = pw->pw_uid;
+	gid1 = pw->pw_gid;
+	uid2 = tst_get_free_uid(uid1);
+
+	umask(0);
+	SAFE_MKDIR(DIR, 0777 | S_ISVTX);
+	dir_fd = SAFE_OPEN(DIR, O_DIRECTORY);
+
+	int fd = SAFE_OPENAT(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777);
+	SAFE_CLOSE(fd);
+	SAFE_MKFIFO(TEST_FIFO_PATH, 0777);
+	SAFE_CHOWN(TEST_FIFO_PATH, uid1, gid1);
+	SAFE_CHOWN(DIR "/" TEST_FILE, uid1, gid1);
+}
+
+static void cleanup(void)
+{
+	if (dir_fd != -1)
+		SAFE_CLOSE(dir_fd);
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.cleanup = cleanup,
+	.needs_root = 1,
+	.tcnt = ARRAY_SIZE(tcases),
+	.test = verify_open,
+	.needs_tmpdir = 1,
+	.forks_child = 1,
+	.save_restore = (const struct tst_path_val[]) {
+		{PROTECTED_REGULAR, NULL, TST_SR_TCONF},
+		{PROTECTED_FIFOS, NULL, TST_SR_TCONF},
+		{}
+	},
+	.tags = (const struct tst_tag[]) {
+		{"linux-git", "30aba6656f61"},
+		{}
+	}
+};
-- 
2.52.0


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH v8 2/2] open16: allow restricted O_CREAT of FIFOs and regular files

[Andrea Cervesato via ltp]

Hi Wei,

> +
> +	if (n == 2) {
> +		SAFE_CHOWN(DIR, -1, gid1);
> +		SAFE_CHMOD(DIR, 0030 | S_ISVTX);
> +	} else {
> +		SAFE_CHOWN(DIR, 0, 0);
> +		SAFE_CHMOD(DIR, 0777 | S_ISVTX);
> +	}

This is not convincing me. We should probably add these values inside the
tcase struct and use a canary value for excluding SAFE_CHOWN/CHMOD from
being used.

Regards,

--
Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v9 0/2] open16: allow restricted O_CREAT of FIFOs and regular files

[Wei Gao via ltp]

v8->v9:
- Use a canary value for excluding SAFE_CHOWN/CHMOD from
being used

Wei Gao (2):
  lib: New library function tst_get_free_uid
  open16: allow restricted O_CREAT of FIFOs and regular files

 include/tst_uid.h                         |   7 +-
 lib/tst_uid.c                             |  26 +++++
 runtest/syscalls                          |   1 +
 testcases/kernel/syscalls/open/.gitignore |   1 +
 testcases/kernel/syscalls/open/open16.c   | 131 ++++++++++++++++++++++
 5 files changed, 164 insertions(+), 2 deletions(-)
 create mode 100644 testcases/kernel/syscalls/open/open16.c

-- 
2.54.0


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v9 1/2] lib: New library function tst_get_free_uid

[Wei Gao via ltp]

Add tst_get_free_uid() to dynamically find unused UIDs for tests.

Signed-off-by: Wei Gao <wegao@suse.com>
---
 include/tst_uid.h |  7 +++++--
 lib/tst_uid.c     | 26 ++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/include/tst_uid.h b/include/tst_uid.h
index 2237ddcbf..394cb3edc 100644
--- a/include/tst_uid.h
+++ b/include/tst_uid.h
@@ -8,10 +8,13 @@
 #include <sys/types.h>
 
 /*
- * Find unassigned gid. The skip argument can be used to ignore e.g. the main
+ * Find unassigned uid/gid. The skip argument can be used to ignore e.g. the main
  * group of a specific user in case it's not listed in the group file. If you
- * do not need to skip any specific gid, simply set it to 0.
+ * do not need to skip any specific id, simply set it to 0.
  */
+uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip);
+#define tst_get_free_uid(skip) tst_get_free_uid_(__FILE__, __LINE__, (skip))
+
 gid_t tst_get_free_gid_(const char *file, const int lineno, gid_t skip);
 #define tst_get_free_gid(skip) tst_get_free_gid_(__FILE__, __LINE__, (skip))
 
diff --git a/lib/tst_uid.c b/lib/tst_uid.c
index af4ef8cf7..deff17085 100644
--- a/lib/tst_uid.c
+++ b/lib/tst_uid.c
@@ -5,6 +5,7 @@
 
 #include <sys/types.h>
 #include <grp.h>
+#include <pwd.h>
 #include <errno.h>
 
 #define TST_NO_DEFAULT_MAIN
@@ -12,6 +13,31 @@
 #include "tst_uid.h"
 
 #define MAX_GID 32767
+#define MAX_UID 32767
+
+uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip)
+{
+	uid_t ret;
+
+	errno = 0;
+
+	for (ret = 1; ret < MAX_UID; ret++) {
+		if (ret == skip || getpwuid(ret))
+			continue;
+
+		if (errno == 0 || errno == ENOENT || errno == ESRCH) {
+			tst_res_(file, lineno, TINFO | TERRNO,
+				"Found unused UID %d", (int)ret);
+			return ret;
+		}
+
+		tst_brk_(file, lineno, TBROK|TERRNO, "User ID lookup failed");
+		return (uid_t)-1;
+	}
+
+	tst_brk_(file, lineno, TBROK, "No free user ID found");
+	return (uid_t)-1;
+}
 
 gid_t tst_get_free_gid_(const char *file, const int lineno, gid_t skip)
 {
-- 
2.54.0


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] lib: New library function tst_get_free_uid

[linuxtestproject.agent]

Hi Wei,

On Tue, 07 Jul 2026 02:29:41 +0000, Wei Gao wrote:
> lib: New library function tst_get_free_uid

--- [PATCH 1/2] ---

> Add tst_get_free_uid() to dynamically find unused UIDs for tests.

The body restates what the subject already says.  What scenario or
test requires a dynamically allocated free UID that tst_get_uids()
cannot cover?

> +uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip);
> +#define tst_get_free_uid(skip) tst_get_free_uid_(__FILE__, __LINE__, (skip))

tst_get_free_uid_() is a new public function in lib/ and include/.
LTP documentation rules require a kernel-doc /** ... */ comment for
new public symbols there.  Something like:

  /**
   * tst_get_free_uid() - Find a UID not assigned to any user.
   * @skip: UID value to skip (pass 0 to skip none).
   *
   * Scans the password database for the first unused UID starting
   * from 1, skipping @skip.  Calls tst_brk(TBROK) if no free UID
   * is found or a lookup error occurs.
   *
   * Return: An unused uid_t value.
   */

> - * Find unassigned gid. The skip argument can be used to ignore e.g. the main
> + * Find unassigned uid/gid. The skip argument can be used to ignore e.g. the main
>   * group of a specific user in case it's not listed in the group file. If you
> - * do not need to skip any specific gid, simply set it to 0.
> + * do not need to skip any specific id, simply set it to 0.

"not listed in the group file" applies to GIDs only.  UIDs live in
the password database (/etc/passwd or NSS passwd).  The comment
should say "password or group file", or be split per-function.

> +uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip)
> +{
> +	uid_t ret;
> +
> +	errno = 0;
> +
> +	for (ret = 1; ret < MAX_UID; ret++) {
> +		if (ret == skip || getpwuid(ret))
> +			continue;
> +
> +		if (errno == 0 || errno == ENOENT || errno == ESRCH) {

POSIX requires callers to set errno = 0 before each call to
getpwuid() so that a NULL return with non-zero errno means error
rather than "entry not found".  The reset here is done once before
the loop.  If a successful getpwuid() call for an earlier UID leaves
errno non-zero (POSIX does not guarantee it is cleared on success),
the next NULL-returning call could be misclassified as an error and
trigger the tst_brk() path below.

A per-iteration reset:

  errno = 0;
  if (ret == skip || getpwuid(ret))
      continue;

would match the POSIX-recommended pattern and make the intent clear.

Verdict - Needs revision

Pre-existing issues:

tst_get_free_gid_() in lib/tst_uid.c has the same errno-reset issue
described above (errno set once before the loop, not before each
getgrgid() call).

---
Note:

The agent can sometimes produce false positives although often its
findings are genuine. If you find issues with the review, please
comment this email or ignore the suggestions.

Regards,
LTP AI Reviewer

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v9 2/2] open16: allow restricted O_CREAT of FIFOs and regular files

[Wei Gao via ltp]

Add LTP coverage for kernel commit 30aba6656f61 (Linux 4.19), which
introduced protection against spoofing attacks via O_CREAT of FIFOs and
regular files in world-writable sticky directories.

This commit adds test cases to verify these security restrictions for
opening FIFOs and regular files in world-writable sticky directories.

Signed-off-by: Wei Gao <wegao@suse.com>
---
 runtest/syscalls                          |   1 +
 testcases/kernel/syscalls/open/.gitignore |   1 +
 testcases/kernel/syscalls/open/open16.c   | 131 ++++++++++++++++++++++
 3 files changed, 133 insertions(+)
 create mode 100644 testcases/kernel/syscalls/open/open16.c

diff --git a/runtest/syscalls b/runtest/syscalls
index a021c79da..4fd62efa8 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -1008,6 +1008,7 @@ open12 open12
 open13 open13
 open14 open14
 open15 open15
+open16 open16
 
 openat01 openat01
 openat02 openat02
diff --git a/testcases/kernel/syscalls/open/.gitignore b/testcases/kernel/syscalls/open/.gitignore
index af5997572..d2cacc02e 100644
--- a/testcases/kernel/syscalls/open/.gitignore
+++ b/testcases/kernel/syscalls/open/.gitignore
@@ -13,3 +13,4 @@
 /open13
 /open14
 /open15
+/open16
diff --git a/testcases/kernel/syscalls/open/open16.c b/testcases/kernel/syscalls/open/open16.c
new file mode 100644
index 000000000..c786cf097
--- /dev/null
+++ b/testcases/kernel/syscalls/open/open16.c
@@ -0,0 +1,131 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2026 Wei Gao <wegao@suse.com>
+ */
+
+/*\
+ * Verify restricted opening of FIFOs and regular files in sticky directories.
+ * This test covers the positive case where access is allowed when protection
+ * is disabled (level 0), and the negative cases where access is disallowed
+ * (EACCES) in world-writable (level 1) or group-writable (level 2) sticky
+ * directories when the file is not owned by the opener.
+ *
+ * This test requires root to modify /proc/sys/fs/protected_* sysctls and
+ * to manage file ownership and permissions in sticky directories.
+ */
+
+#include <pwd.h>
+#include <stdlib.h>
+#include "tst_test.h"
+#include "tst_safe_file_at.h"
+#include "tst_uid.h"
+
+#define DIR "ltp_tmp_check1"
+#define TEST_FILE "test_file_1"
+#define TEST_FIFO "test_fifo_1"
+#define PROTECTED_REGULAR "/proc/sys/fs/protected_regular"
+#define PROTECTED_FIFOS "/proc/sys/fs/protected_fifos"
+#define TEST_FIFO_PATH DIR "/" TEST_FIFO
+
+static int dir_fd = -1;
+static uid_t uid1, uid2;
+static gid_t gid1;
+
+static struct tcase {
+	char *level;
+	int exp_errno;
+	uid_t owner_uid;
+	int use_nobody_gid;
+	mode_t dir_mode;
+} tcases[] = {
+	{"0", 0,      0,  0, 0777 | S_ISVTX},
+	{"1", EACCES, 0,  0, 0777 | S_ISVTX},
+	{"2", EACCES, -1, 1, 0030 | S_ISVTX},
+};
+
+static void verify_open(unsigned int n)
+{
+	struct tcase *tc = &tcases[n];
+	pid_t pid;
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "%s", tc->level);
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "%s", tc->level);
+
+	if (tc->owner_uid != (uid_t)-1 || tc->use_nobody_gid) {
+		gid_t gid = tc->use_nobody_gid ? gid1 : 0;
+		SAFE_CHOWN(DIR, tc->owner_uid, gid);
+	}
+
+	if (tc->dir_mode)
+		SAFE_CHMOD(DIR, tc->dir_mode);
+
+	pid = SAFE_FORK();
+	if (!pid) {
+		SAFE_SETGID(gid1);
+		SAFE_SETUID(uid2);
+
+		if (tc->exp_errno) {
+			TST_EXP_FAIL2(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777),
+				tc->exp_errno, "openat %s (Level %s)", TEST_FILE, tc->level);
+			TST_EXP_FAIL2(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777),
+				tc->exp_errno, "open %s (Level %s)", TEST_FIFO, tc->level);
+		} else {
+			int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
+			if (TST_PASS)
+				SAFE_CLOSE(fd);
+
+			fd = TST_EXP_FD(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777));
+			if (TST_PASS)
+				SAFE_CLOSE(fd);
+		}
+
+		exit(0);
+	}
+
+	SAFE_WAITPID(pid, NULL, 0);
+}
+
+static void setup(void)
+{
+	struct passwd *pw;
+
+	pw = SAFE_GETPWNAM("nobody");
+	uid1 = pw->pw_uid;
+	gid1 = pw->pw_gid;
+	uid2 = tst_get_free_uid(uid1);
+
+	umask(0);
+	SAFE_MKDIR(DIR, 0777 | S_ISVTX);
+	dir_fd = SAFE_OPEN(DIR, O_DIRECTORY);
+
+	int fd = SAFE_OPENAT(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777);
+	SAFE_CLOSE(fd);
+	SAFE_MKFIFO(TEST_FIFO_PATH, 0777);
+	SAFE_CHOWN(TEST_FIFO_PATH, uid1, gid1);
+	SAFE_CHOWN(DIR "/" TEST_FILE, uid1, gid1);
+}
+
+static void cleanup(void)
+{
+	if (dir_fd != -1)
+		SAFE_CLOSE(dir_fd);
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.cleanup = cleanup,
+	.needs_root = 1,
+	.tcnt = ARRAY_SIZE(tcases),
+	.test = verify_open,
+	.needs_tmpdir = 1,
+	.forks_child = 1,
+	.save_restore = (const struct tst_path_val[]) {
+		{PROTECTED_REGULAR, NULL, TST_SR_TCONF},
+		{PROTECTED_FIFOS, NULL, TST_SR_TCONF},
+		{}
+	},
+	.tags = (const struct tst_tag[]) {
+		{"linux-git", "30aba6656f61"},
+		{}
+	}
+};
-- 
2.54.0


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v7 2/2] open16: allow restricted O_CREAT of FIFOs and regular files

[Wei Gao via ltp]

This commit adds test cases to verify the security restrictions for opening
FIFOs and regular files in world-writable sticky directories.

Signed-off-by: Wei Gao <wegao@suse.com>
---
 runtest/syscalls                          |   1 +
 testcases/kernel/syscalls/open/.gitignore |   1 +
 testcases/kernel/syscalls/open/open16.c   | 132 ++++++++++++++++++++++
 3 files changed, 134 insertions(+)
 create mode 100644 testcases/kernel/syscalls/open/open16.c

diff --git a/runtest/syscalls b/runtest/syscalls
index d72fceb5e..c14ebb3a0 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -1005,6 +1005,7 @@ open12 open12
 open13 open13
 open14 open14
 open15 open15
+open16 open16
 
 openat01 openat01
 openat02 openat02
diff --git a/testcases/kernel/syscalls/open/.gitignore b/testcases/kernel/syscalls/open/.gitignore
index af5997572..d2cacc02e 100644
--- a/testcases/kernel/syscalls/open/.gitignore
+++ b/testcases/kernel/syscalls/open/.gitignore
@@ -13,3 +13,4 @@
 /open13
 /open14
 /open15
+/open16
diff --git a/testcases/kernel/syscalls/open/open16.c b/testcases/kernel/syscalls/open/open16.c
new file mode 100644
index 000000000..726b05df9
--- /dev/null
+++ b/testcases/kernel/syscalls/open/open16.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2026 Wei Gao <wegao@suse.com>
+ */
+
+/*\
+ * Verify restricted opening of FIFOs and regular files in sticky directories.
+ * This test covers the positive case where access is allowed when protection
+ * is disabled (level 0), and the negative cases where access is disallowed
+ * (EACCES) in world-writable (level 1) or group-writable (level 2) sticky
+ * directories when the file is not owned by the opener.
+ */
+
+#include <pwd.h>
+#include <stdlib.h>
+#include "tst_test.h"
+#include "tst_safe_file_at.h"
+#include "tst_uid.h"
+
+#define DIR "ltp_tmp_check1"
+#define TEST_FILE "test_file_1"
+#define TEST_FIFO "test_fifo_1"
+#define PROTECTED_REGULAR "/proc/sys/fs/protected_regular"
+#define PROTECTED_FIFOS "/proc/sys/fs/protected_fifos"
+#define TEST_FIFO_PATH DIR "/" TEST_FIFO
+
+static int dir_fd = -1;
+static uid_t uid1, uid2;
+
+static void run(void)
+{
+	SAFE_CHMOD(DIR, 0777 | S_ISVTX);
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "0");
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "0");
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(uid1);
+
+		int fd = SAFE_OPENAT(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777);
+
+		SAFE_CLOSE(fd);
+
+		SAFE_MKFIFO(TEST_FIFO_PATH, 0777);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(uid2);
+
+		int fd = TST_EXP_FD(openat(dir_fd, TEST_FILE, O_CREAT | O_RDWR, 0777));
+
+		if (TST_PASS)
+			SAFE_CLOSE(fd);
+
+		fd = TST_EXP_FD(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777));
+
+		if (TST_PASS)
+			SAFE_CLOSE(fd);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "1");
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "1");
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(uid2);
+		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
+		TST_EXP_FAIL(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777), EACCES);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+
+	SAFE_FILE_PRINTF(PROTECTED_REGULAR, "2");
+	SAFE_FILE_PRINTF(PROTECTED_FIFOS, "2");
+	SAFE_CHMOD(DIR, 0020 | S_ISVTX);
+
+	if (!SAFE_FORK()) {
+		SAFE_SETUID(uid2);
+		TST_EXP_FAIL(openat(dir_fd, TEST_FILE, O_RDWR | O_CREAT, 0777), EACCES);
+		TST_EXP_FAIL(open(TEST_FIFO_PATH, O_RDWR | O_CREAT, 0777), EACCES);
+
+		exit(0);
+	}
+
+	tst_reap_children();
+	SAFE_UNLINK(TEST_FIFO_PATH);
+}
+
+static void setup(void)
+{
+	struct passwd *pw;
+
+	pw = SAFE_GETPWNAM("nobody");
+	uid1 = pw->pw_uid;
+	uid2 = tst_get_free_uid(uid1);
+
+	umask(0);
+	SAFE_MKDIR(DIR, 0777 | S_ISVTX);
+	dir_fd = SAFE_OPEN(DIR, O_DIRECTORY);
+}
+
+static void cleanup(void)
+{
+	if (dir_fd != -1)
+		SAFE_CLOSE(dir_fd);
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.cleanup = cleanup,
+	.needs_root = 1,
+	.test_all = run,
+	.needs_tmpdir = 1,
+	.forks_child = 1,
+	.save_restore = (const struct tst_path_val[]) {
+		{PROTECTED_REGULAR, NULL, TST_SR_TCONF},
+		{PROTECTED_FIFOS, NULL, TST_SR_TCONF},
+		{}
+	},
+	.tags = (const struct tst_tag[]) {
+		{"linux-git", "30aba6656f61"},
+		{}
+	}
+};
-- 
2.52.0


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v10 1/2] lib: New library function tst_get_free_uid

[Wei Gao via ltp]

Add tst_get_free_uid() to dynamically find unused UIDs for tests.

Some tests need a completely unassigned, unused UID. This is used by
open16 to verify restricted O_CREAT in sticky directories by running
as a sandboxed user with no file ownership or privileges.

Signed-off-by: Wei Gao <wegao@suse.com>
---
 include/tst_uid.h | 27 +++++++++++++++++++++++----
 lib/tst_uid.c     | 28 ++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/include/tst_uid.h b/include/tst_uid.h
index 2237ddcbf..2ffe84613 100644
--- a/include/tst_uid.h
+++ b/include/tst_uid.h
@@ -7,10 +7,29 @@
 
 #include <sys/types.h>
 
-/*
- * Find unassigned gid. The skip argument can be used to ignore e.g. the main
- * group of a specific user in case it's not listed in the group file. If you
- * do not need to skip any specific gid, simply set it to 0.
+/**
+ * tst_get_free_uid() - Find a UID not assigned to any user.
+ * @skip: UID value to skip (pass 0 to skip none).
+ *
+ * Scans the password database for the first unused UID starting
+ * from 1, skipping @skip. Calls tst_brk(TBROK) if no free UID
+ * is found or a lookup error occurs.
+ *
+ * Return: An unused uid_t value.
+ */
+uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip);
+#define tst_get_free_uid(skip) tst_get_free_uid_(__FILE__, __LINE__, (skip))
+
+/**
+ * tst_get_free_gid() - Find a GID not assigned to any group.
+ * @skip: GID value to skip (pass 0 to skip none).
+ *
+ * Scans the group database for the first unused GID starting from 1,
+ * skipping @skip. The @skip argument can be used to ignore e.g. the main
+ * group of a specific user in case it's not listed in the group file.
+ * Calls tst_brk(TBROK) if no free GID is found or a lookup error occurs.
+ *
+ * Return: An unused gid_t value.
  */
 gid_t tst_get_free_gid_(const char *file, const int lineno, gid_t skip);
 #define tst_get_free_gid(skip) tst_get_free_gid_(__FILE__, __LINE__, (skip))
diff --git a/lib/tst_uid.c b/lib/tst_uid.c
index af4ef8cf7..93c9b83d2 100644
--- a/lib/tst_uid.c
+++ b/lib/tst_uid.c
@@ -5,6 +5,7 @@
 
 #include <sys/types.h>
 #include <grp.h>
+#include <pwd.h>
 #include <errno.h>
 
 #define TST_NO_DEFAULT_MAIN
@@ -12,6 +13,33 @@
 #include "tst_uid.h"
 
 #define MAX_GID 32767
+#define MAX_UID 32767
+
+uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip)
+{
+	uid_t ret;
+
+	for (ret = 1; ret < MAX_UID; ret++) {
+		if (ret == skip)
+			continue;
+
+		errno = 0;
+		if (getpwuid(ret))
+			continue;
+
+		if (errno == 0 || errno == ENOENT || errno == ESRCH) {
+			tst_res_(file, lineno, TINFO | TERRNO,
+				"Found unused UID %d", (int)ret);
+			return ret;
+		}
+
+		tst_brk_(file, lineno, TBROK | TERRNO, "User ID lookup failed");
+		return (uid_t)-1;
+	}
+
+	tst_brk_(file, lineno, TBROK, "No free user ID found");
+	return (uid_t)-1;
+}
 
 gid_t tst_get_free_gid_(const char *file, const int lineno, gid_t skip)
 {
-- 
2.54.0


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] lib: New library function tst_get_free_uid

[linuxtestproject.agent]

Hi Wei,

On Tue, 7 Jul 2026 05:47:53 +0000, Wei Gao wrote:
> lib: New library function tst_get_free_uid

--- [PATCH 1/2] ---

> +/**
> + * tst_get_free_uid() - Find a UID not assigned to any user.
> + * @skip: UID value to skip (pass 0 to skip none).

The summary line says tst_get_free_uid() but the symbol being declared
is tst_get_free_uid_(). linuxdoc requires the summary name to match the
symbol exactly, so it would fail to associate this /** block with the
implementation.

Should this be "tst_get_free_uid_() - ..." to match the symbol, or is
the intent to document the macro tst_get_free_uid() instead?

Same issue applies to the modified tst_get_free_gid() summary below.

> +uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip);

The function has three parameters but the kernel-doc block only documents
@skip. linuxdoc expects an @name: entry for every parameter in declaration
order. @file and @lineno are missing.

Same gap in the modified tst_get_free_gid_() block.

> +		if (errno == 0 || errno == ENOENT || errno == ESRCH) {
> +			tst_res_(file, lineno, TINFO | TERRNO,
> +				"Found unused UID %d", (int)ret);
> +			return ret;

When getpwuid() returns NULL with errno set to ENOENT or ESRCH, TERRNO
appends the errno string to the message, producing output like:
"Found unused UID 5: No such file or directory". The function succeeded,
so the error string is misleading. Should TERRNO be dropped here, or
should it be conditionally omitted when errno indicates "not found"?

--- [PATCH 2/2] ---

> +Add LTP coverage for kernel commit 30aba6656f61 (Linux 4.19), which
> +introduced protection against spoofing attacks via O_CREAT of FIFOs and
> +regular files in world-writable sticky directories.
> +
> +This commit adds test cases to verify these security restrictions for
> +opening FIFOs and regular files in world-writable sticky directories.

tcase[2] uses dir_mode=0030|SVTX (group-writable sticky, level 2), which
the commit body doesn't mention. The test's own doc block describes both
"world-writable (level 1) or group-writable (level 2)" correctly — does
the body need updating to match?

Verdict - Needs revision

---
Note:

The agent can sometimes produce false positives although often its
findings are genuine. If you find issues with the review, please
comment this email or ignore the suggestions.

Regards,
LTP AI Reviewer

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

[LTP] [PATCH v11 1/2] lib: New library function tst_get_free_uid

[Wei Gao via ltp]

Add tst_get_free_uid() to dynamically find unused UIDs for tests.

Some tests need a completely unassigned, unused UID. This is used by
open16 to verify restricted O_CREAT in sticky directories by running
as a sandboxed user with no file ownership or privileges.

Signed-off-by: Wei Gao <wegao@suse.com>
---
 include/tst_uid.h | 29 +++++++++++++++++++++++++----
 lib/tst_uid.c     | 30 +++++++++++++++++++++++++++++-
 2 files changed, 54 insertions(+), 5 deletions(-)

diff --git a/include/tst_uid.h b/include/tst_uid.h
index 2237ddcbf..c73450956 100644
--- a/include/tst_uid.h
+++ b/include/tst_uid.h
@@ -7,12 +7,33 @@
 
 #include <sys/types.h>
 
-/*
- * Find unassigned gid. The skip argument can be used to ignore e.g. the main
- * group of a specific user in case it's not listed in the group file. If you
- * do not need to skip any specific gid, simply set it to 0.
+uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip);
+
+/**
+ * tst_get_free_uid() - Find a UID not assigned to any user.
+ * @skip: UID value to skip (pass 0 to skip none).
+ *
+ * Scans the password database for the first unused UID starting
+ * from 1, skipping @skip. Calls tst_brk(TBROK) if no free UID
+ * is found or a lookup error occurs.
+ *
+ * Return: An unused uid_t value.
  */
+#define tst_get_free_uid(skip) tst_get_free_uid_(__FILE__, __LINE__, (skip))
+
 gid_t tst_get_free_gid_(const char *file, const int lineno, gid_t skip);
+
+/**
+ * tst_get_free_gid() - Find a GID not assigned to any group.
+ * @skip: GID value to skip (pass 0 to skip none).
+ *
+ * Scans the group database for the first unused GID starting from 1,
+ * skipping @skip. The @skip argument can be used to ignore e.g. the main
+ * group of a specific user in case it's not listed in the group file.
+ * Calls tst_brk(TBROK) if no free GID is found or a lookup error occurs.
+ *
+ * Return: An unused gid_t value.
+ */
 #define tst_get_free_gid(skip) tst_get_free_gid_(__FILE__, __LINE__, (skip))
 
 /*
diff --git a/lib/tst_uid.c b/lib/tst_uid.c
index af4ef8cf7..47c267bc4 100644
--- a/lib/tst_uid.c
+++ b/lib/tst_uid.c
@@ -5,6 +5,7 @@
 
 #include <sys/types.h>
 #include <grp.h>
+#include <pwd.h>
 #include <errno.h>
 
 #define TST_NO_DEFAULT_MAIN
@@ -12,6 +13,33 @@
 #include "tst_uid.h"
 
 #define MAX_GID 32767
+#define MAX_UID 32767
+
+uid_t tst_get_free_uid_(const char *file, const int lineno, uid_t skip)
+{
+	uid_t ret;
+
+	for (ret = 1; ret < MAX_UID; ret++) {
+		if (ret == skip)
+			continue;
+
+		errno = 0;
+		if (getpwuid(ret))
+			continue;
+
+		if (errno == 0 || errno == ENOENT || errno == ESRCH) {
+			tst_res_(file, lineno, TINFO,
+				"Found unused UID %d", (int)ret);
+			return ret;
+		}
+
+		tst_brk_(file, lineno, TBROK | TERRNO, "User ID lookup failed");
+		return (uid_t)-1;
+	}
+
+	tst_brk_(file, lineno, TBROK, "No free user ID found");
+	return (uid_t)-1;
+}
 
 gid_t tst_get_free_gid_(const char *file, const int lineno, gid_t skip)
 {
@@ -24,7 +52,7 @@ gid_t tst_get_free_gid_(const char *file, const int lineno, gid_t skip)
 			continue;
 
 		if (errno == 0 || errno == ENOENT || errno == ESRCH) {
-			tst_res_(file, lineno, TINFO | TERRNO,
+			tst_res_(file, lineno, TINFO,
 				"Found unused GID %d", (int)ret);
 			return ret;
 		}
-- 
2.54.0


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] lib: New library function tst_get_free_uid

[linuxtestproject.agent]

Hi Wei,

On Tue, 21 Jul 2026 07:41:28 +0000, Wei Gao wrote:
> lib: New library function tst_get_free_uid

--- [PATCH 1/2] ---

> -		tst_res_(file, lineno, TINFO | TERRNO,
> +		tst_res_(file, lineno, TINFO,
>  			"Found unused GID %d", (int)ret);

This hunk is a fix to the existing tst_get_free_gid_() success path --
removing | TERRNO so errno is not printed when a free GID is found.

That is a reasonable fix on its own, but it has no relationship to the
new tst_get_free_uid() API that the commit message describes. The commit
message does not mention it.

Could these be split into two patches?

  1/3  lib/tst_uid: Remove spurious TERRNO from tst_get_free_gid success path
  2/3  lib: New library function tst_get_free_uid
  3/3  open16: allow restricted O_CREAT of FIFOs and regular files

Verdict - Needs revision

---
Note:

The agent can sometimes produce false positives although often its
findings are genuine. If you find issues with the review, please
comment this email or ignore the suggestions.

Regards,
LTP AI Reviewer

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp