Messages in this thread Patch in this message | | | From | Ran Xiaokai <> | Subject | [PATCH] tests: add mqueue sysctl tests for user namespace | Date | Sun, 22 Aug 2021 20:29:09 -0700 |
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when a ipc namespace is created in a user namespace, the mqueue sysctl files should be writalbe to the owner of the user namespace. Even the owner is not a global privileged user.
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn> --- tools/testing/selftests/Makefile | 1 + tools/testing/selftests/mqueue_sysctl/Makefile | 7 + tools/testing/selftests/mqueue_sysctl/config | 2 + .../selftests/mqueue_sysctl/mq_sysctl_test.c | 172 +++++++++++++++++++++ 4 files changed, 182 insertions(+) create mode 100644 tools/testing/selftests/mqueue_sysctl/Makefile create mode 100644 tools/testing/selftests/mqueue_sysctl/config create mode 100644 tools/testing/selftests/mqueue_sysctl/mq_sysctl_test.c
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index bc3299a..2031591 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -36,6 +36,7 @@ TARGETS += mincore TARGETS += mount TARGETS += mount_setattr TARGETS += mqueue +TARGETS += mqueue_sysctl TARGETS += nci TARGETS += net TARGETS += net/forwarding diff --git a/tools/testing/selftests/mqueue_sysctl/Makefile b/tools/testing/selftests/mqueue_sysctl/Makefile new file mode 100644 index 0000000..44b6633 --- /dev/null +++ b/tools/testing/selftests/mqueue_sysctl/Makefile @@ -0,0 +1,7 @@ +# SPDX-License-Identifier: GPL-2.0 +CFLAGS += -O2 +LDLIBS = -lrt + +TEST_GEN_PROGS := mq_sysctl_test + +include ../lib.mk diff --git a/tools/testing/selftests/mqueue_sysctl/config b/tools/testing/selftests/mqueue_sysctl/config new file mode 100644 index 0000000..68b2794 --- /dev/null +++ b/tools/testing/selftests/mqueue_sysctl/config @@ -0,0 +1,2 @@ +CONFIG_USER_NS=y +CONFIG_POSIX_MQUEUE_SYSCTL=y \ No newline at end of file diff --git a/tools/testing/selftests/mqueue_sysctl/mq_sysctl_test.c b/tools/testing/selftests/mqueue_sysctl/mq_sysctl_test.c new file mode 100644 index 0000000..48023d5 --- /dev/null +++ b/tools/testing/selftests/mqueue_sysctl/mq_sysctl_test.c @@ -0,0 +1,172 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <stdio.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <unistd.h> +#include <errno.h> +#include <sched.h> +#include <sys/mount.h> +#include <mqueue.h> +#include <sys/wait.h> +#include <string.h> + +#include "../kselftest_harness.h" + +static ssize_t write_nointr(int fd, const void *buf, size_t count) +{ + ssize_t ret; + + do { + ret = write(fd, buf, count); + } while (ret < 0 && errno == EINTR); + + return ret; +} + +static int write_file(const char *path, const void *buf, size_t count) +{ + int fd; + ssize_t ret; + + fd = open(path, O_WRONLY | O_CLOEXEC | O_NOCTTY | O_NOFOLLOW); + if (fd < 0) + return -1; + + ret = write_nointr(fd, buf, count); + close(fd); + if (ret < 0 || (size_t)ret != count) + return -1; + + return 0; +} + +static int create_and_enter_userns(void) +{ + uid_t uid; + gid_t gid; + char map[100]; + + uid = getuid(); + gid = getgid(); + + if (unshare(CLONE_NEWUSER)) + return -1; + + if (write_file("/proc/self/setgroups", "deny", sizeof("deny") - 1) && + errno != ENOENT) + return -1; + + snprintf(map, sizeof(map), "0 %d 1", uid); + if (write_file("/proc/self/uid_map", map, strlen(map))) + return -1; + + snprintf(map, sizeof(map), "0 %d 1", gid); + if (write_file("/proc/self/gid_map", map, strlen(map))) + return -1; + + if (setgid(0)) + return -1; + + if (setuid(0)) + return -1; + + return 0; +} + +static int prepare_unpriv_mountns(void) +{ + if (create_and_enter_userns()) + return -1; + + if (unshare(CLONE_NEWNS)) + return -1; + + if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0)) + return -1; + + if (unshare(CLONE_NEWIPC)) + return -1; + + return 0; +} + +static int wait_for_pid(pid_t pid) +{ + int status, ret; + +again: + ret = waitpid(pid, &status, 0); + if (ret == -1) { + if (errno == EINTR) + goto again; + + return -1; + } + + if (!WIFEXITED(status)) + return -1; + + return WEXITSTATUS(status); +} + +int get_mq_queues_max(void) +{ + int fd; + char buf[16]; + int val = -1; + + fd = open("/proc/sys/fs/mqueue/queues_max", O_RDONLY); + if (fd >= 0) { + if (read(fd, buf, sizeof(buf)) > 0) + val = atoi(buf); + + close(fd); + return val; + } + return val; +} + +TEST(mqueue_sysctl) +{ + pid_t pid; + int qmax1, qmax2; + + chdir(getenv("HOME")); + /* read and stash the original sysctl value */ + qmax1 = get_mq_queues_max(); + ASSERT_GE(qmax1, 0); + + pid = fork(); + ASSERT_GE(pid, 0); + + if (pid == 0) { + ASSERT_EQ(prepare_unpriv_mountns(), 0); + + if (mkdir("./mqueue", 755) && errno != EEXIST) + SKIP(return, "mkdir /dev/mqueue failed"); + + ASSERT_EQ(mount("none", "./mqueue", "mqueue", MS_NOATIME, NULL), 0); + + /* modify the sysctl value in new ipc namesapce */ + ASSERT_EQ(write_file("/proc/sys/fs/mqueue/queues_max", "1", 1), 0); + + ASSERT_GE(mq_open("/new_ns1", O_RDWR | O_CREAT, 0644, NULL), 0); + + /* mq_open() should fail as exceeding of queues_max */ + ASSERT_EQ(mq_open("/new_ns2", O_RDWR | O_CREAT, 0644, NULL), -1); + + ASSERT_EQ(mq_unlink("/new_ns1"), 0); + ASSERT_EQ(umount("./mqueue"), 0); + + exit(0); + } + + ASSERT_EQ(wait_for_pid(pid), 0); + + qmax2 = get_mq_queues_max(); + ASSERT_EQ(qmax1, qmax2); +} + +TEST_HARNESS_MAIN -- 2.15.2
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