Unverified Commit 8199e6f7 authored by Amir Goldstein's avatar Amir Goldstein Committed by Christian Brauner
Browse files

selftests/filesystems: create setup_userns() helper 



Add helper to utils.c and use it in statmount userns tests.

Reviewed-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/20250509133240.529330-8-amir73il@gmail.com


Reviewed-by: default avatarChristian Brauner <brauner@kernel.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent e897b9b1

tools/testing/selftests/filesystems/statmount/statmount_test_ns.c

+1 −57
Original line number Diff line number Diff line
@@ -79,66 +79,10 @@ static int get_mnt_ns_id(const char *mnt_ns, uint64_t *mnt_ns_id) 
	return NSID_PASS;

}



static int write_file(const char *path, const char *val)

{

	int fd = open(path, O_WRONLY);

	size_t len = strlen(val);

	int ret;



	if (fd == -1) {

		ksft_print_msg("opening %s for write: %s\n", path, strerror(errno));

		return NSID_ERROR;

	}



	ret = write(fd, val, len);

	if (ret == -1) {

		ksft_print_msg("writing to %s: %s\n", path, strerror(errno));

		return NSID_ERROR;

	}

	if (ret != len) {

		ksft_print_msg("short write to %s\n", path);

		return NSID_ERROR;

	}



	ret = close(fd);

	if (ret == -1) {

		ksft_print_msg("closing %s\n", path);

		return NSID_ERROR;

	}



	return NSID_PASS;

}



static int setup_namespace(void)

{

	int ret;

	char buf[32];

	uid_t uid = getuid();

	gid_t gid = getgid();



	ret = unshare(CLONE_NEWNS|CLONE_NEWUSER|CLONE_NEWPID);

	if (ret == -1)

		ksft_exit_fail_msg("unsharing mountns and userns: %s\n",

				   strerror(errno));



	sprintf(buf, "0 %d 1", uid);

	ret = write_file("/proc/self/uid_map", buf);

	if (ret != NSID_PASS)

		return ret;

	ret = write_file("/proc/self/setgroups", "deny");

	if (ret != NSID_PASS)

		return ret;

	sprintf(buf, "0 %d 1", gid);

	ret = write_file("/proc/self/gid_map", buf);

	if (ret != NSID_PASS)

		return ret;



	ret = mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);

	if (ret == -1) {

		ksft_print_msg("making mount tree private: %s\n",

			       strerror(errno));

	if (setup_userns() != 0)

		return NSID_ERROR;

	}



	return NSID_PASS;

}

tools/testing/selftests/filesystems/utils.c

+66 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <sys/types.h>

#include <sys/wait.h>

#include <sys/xattr.h>

#include <sys/mount.h>



#include "../kselftest.h"

#include "wrappers.h"
@@ -449,6 +450,71 @@ static int create_userns_hierarchy(struct userns_hierarchy *h) 
	return fret;

}



static int write_file(const char *path, const char *val)

{

	int fd = open(path, O_WRONLY);

	size_t len = strlen(val);

	int ret;



	if (fd == -1) {

		ksft_print_msg("opening %s for write: %s\n", path, strerror(errno));

		return -1;

	}



	ret = write(fd, val, len);

	if (ret == -1) {

		ksft_print_msg("writing to %s: %s\n", path, strerror(errno));

		return -1;

	}

	if (ret != len) {

		ksft_print_msg("short write to %s\n", path);

		return -1;

	}



	ret = close(fd);

	if (ret == -1) {

		ksft_print_msg("closing %s\n", path);

		return -1;

	}



	return 0;

}



int setup_userns(void)

{

	int ret;

	char buf[32];

	uid_t uid = getuid();

	gid_t gid = getgid();



	ret = unshare(CLONE_NEWNS|CLONE_NEWUSER|CLONE_NEWPID);

	if (ret) {

		ksft_exit_fail_msg("unsharing mountns and userns: %s\n",

				   strerror(errno));

		return ret;

	}



	sprintf(buf, "0 %d 1", uid);

	ret = write_file("/proc/self/uid_map", buf);

	if (ret)

		return ret;

	ret = write_file("/proc/self/setgroups", "deny");

	if (ret)

		return ret;

	sprintf(buf, "0 %d 1", gid);

	ret = write_file("/proc/self/gid_map", buf);

	if (ret)

		return ret;



	ret = mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);

	if (ret) {

		ksft_print_msg("making mount tree private: %s\n", strerror(errno));

		return ret;

	}



	return 0;

}



/* caps_down - lower all effective caps */

int caps_down(void)

{

tools/testing/selftests/filesystems/utils.h

+1 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ extern int caps_down(void); 
extern int cap_down(cap_value_t down);



extern bool switch_ids(uid_t uid, gid_t gid);

extern int setup_userns(void);



static inline bool switch_userns(int fd, uid_t uid, gid_t gid, bool drop_caps)

{