diff options
Diffstat (limited to 'tools/testing/selftests/namespaces/listns_efault_test.c')
| -rw-r--r-- | tools/testing/selftests/namespaces/listns_efault_test.c | 530 |
1 files changed, 530 insertions, 0 deletions
diff --git a/tools/testing/selftests/namespaces/listns_efault_test.c b/tools/testing/selftests/namespaces/listns_efault_test.c new file mode 100644 index 000000000000..c7ed4023d7a8 --- /dev/null +++ b/tools/testing/selftests/namespaces/listns_efault_test.c @@ -0,0 +1,530 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <errno.h> +#include <fcntl.h> +#include <limits.h> +#include <sched.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <linux/nsfs.h> +#include <sys/ioctl.h> +#include <sys/mman.h> +#include <sys/mount.h> +#include <sys/socket.h> +#include <sys/stat.h> +#include <sys/syscall.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <unistd.h> +#include "../kselftest_harness.h" +#include "../filesystems/utils.h" +#include "../pidfd/pidfd.h" +#include "wrappers.h" + +/* + * Test listns() error handling with invalid buffer addresses. + * + * When the buffer pointer is invalid (e.g., crossing page boundaries + * into unmapped memory), listns() returns EINVAL. + * + * This test also creates mount namespaces that get destroyed during + * iteration, testing that namespace cleanup happens outside the RCU + * read lock. + */ +TEST(listns_partial_fault_with_ns_cleanup) +{ + void *map; + __u64 *ns_ids; + ssize_t ret; + long page_size; + pid_t pid, iter_pid; + int pidfds[5]; + int sv[5][2]; + int iter_pidfd; + int i, status; + char c; + + page_size = sysconf(_SC_PAGESIZE); + ASSERT_GT(page_size, 0); + + /* + * Map two pages: + * - First page: readable and writable + * - Second page: will be unmapped to trigger EFAULT + */ + map = mmap(NULL, page_size * 2, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + ASSERT_NE(map, MAP_FAILED); + + /* Unmap the second page */ + ret = munmap((char *)map + page_size, page_size); + ASSERT_EQ(ret, 0); + + /* + * Position the buffer pointer so there's room for exactly one u64 + * before the page boundary. The second u64 would fall into the + * unmapped page. + */ + ns_ids = ((__u64 *)((char *)map + page_size)) - 1; + + /* + * Create a separate process to run listns() in a loop concurrently + * with namespace creation and destruction. + */ + iter_pid = create_child(&iter_pidfd, 0); + ASSERT_NE(iter_pid, -1); + + if (iter_pid == 0) { + struct ns_id_req req = { + .size = sizeof(req), + .spare = 0, + .ns_id = 0, + .ns_type = 0, /* All types */ + .spare2 = 0, + .user_ns_id = 0, /* Global listing */ + }; + int iter_ret; + + /* + * Loop calling listns() until killed. + * The kernel should: + * 1. Successfully write the first namespace ID (within valid page) + * 2. Fail with EFAULT when trying to write the second ID (unmapped page) + * 3. Handle concurrent namespace destruction without deadlock + */ + while (1) { + iter_ret = sys_listns(&req, ns_ids, 2, 0); + + if (iter_ret == -1 && errno == ENOSYS) + _exit(PIDFD_SKIP); + } + } + + /* Small delay to let iterator start looping */ + usleep(50000); + + /* + * Create several child processes, each in its own mount namespace. + * These will be destroyed while the iterator is running listns(). + */ + for (i = 0; i < 5; i++) { + /* Create socketpair for synchronization */ + ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sv[i]), 0); + + pid = create_child(&pidfds[i], CLONE_NEWNS); + ASSERT_NE(pid, -1); + + if (pid == 0) { + close(sv[i][0]); /* Close parent end */ + + if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0)) + _exit(1); + + /* Child: create a couple of tmpfs mounts */ + if (mkdir("/tmp/test_mnt1", 0755) == -1 && errno != EEXIST) + _exit(1); + if (mkdir("/tmp/test_mnt2", 0755) == -1 && errno != EEXIST) + _exit(1); + + if (mount("tmpfs", "/tmp/test_mnt1", "tmpfs", 0, NULL) == -1) + _exit(1); + if (mount("tmpfs", "/tmp/test_mnt2", "tmpfs", 0, NULL) == -1) + _exit(1); + + /* Signal parent that setup is complete */ + if (write_nointr(sv[i][1], "R", 1) != 1) + _exit(1); + + /* Wait for parent to signal us to exit */ + if (read_nointr(sv[i][1], &c, 1) != 1) + _exit(1); + + close(sv[i][1]); + _exit(0); + } + + close(sv[i][1]); /* Close child end */ + } + + /* Wait for all children to finish setup */ + for (i = 0; i < 5; i++) { + ret = read_nointr(sv[i][0], &c, 1); + ASSERT_EQ(ret, 1); + ASSERT_EQ(c, 'R'); + } + + /* + * Signal children to exit. This will destroy their mount namespaces + * while listns() is iterating the namespace tree. + * This tests that cleanup happens outside the RCU read lock. + */ + for (i = 0; i < 5; i++) + write_nointr(sv[i][0], "X", 1); + + /* Wait for all mount namespace children to exit and cleanup */ + for (i = 0; i < 5; i++) { + waitpid(-1, NULL, 0); + close(sv[i][0]); + close(pidfds[i]); + } + + /* Kill iterator and wait for it */ + sys_pidfd_send_signal(iter_pidfd, SIGKILL, NULL, 0); + ret = waitpid(iter_pid, &status, 0); + ASSERT_EQ(ret, iter_pid); + close(iter_pidfd); + + /* Should have been killed */ + ASSERT_TRUE(WIFSIGNALED(status)); + ASSERT_EQ(WTERMSIG(status), SIGKILL); + + /* Clean up */ + munmap(map, page_size); +} + +/* + * Test listns() error handling when the entire buffer is invalid. + * This is a sanity check that basic invalid pointer detection works. + */ +TEST(listns_complete_fault) +{ + struct ns_id_req req = { + .size = sizeof(req), + .spare = 0, + .ns_id = 0, + .ns_type = 0, + .spare2 = 0, + .user_ns_id = 0, + }; + __u64 *ns_ids; + ssize_t ret; + + /* Use a clearly invalid pointer */ + ns_ids = (__u64 *)0xdeadbeef; + + ret = sys_listns(&req, ns_ids, 10, 0); + + if (ret == -1 && errno == ENOSYS) + SKIP(return, "listns() not supported"); + + /* Should fail with EFAULT */ + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, EFAULT); +} + +/* + * Test listns() error handling when the buffer is NULL. + */ +TEST(listns_null_buffer) +{ + struct ns_id_req req = { + .size = sizeof(req), + .spare = 0, + .ns_id = 0, + .ns_type = 0, + .spare2 = 0, + .user_ns_id = 0, + }; + ssize_t ret; + + /* NULL buffer with non-zero count should fail */ + ret = sys_listns(&req, NULL, 10, 0); + + if (ret == -1 && errno == ENOSYS) + SKIP(return, "listns() not supported"); + + /* Should fail with EFAULT */ + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, EFAULT); +} + +/* + * Test listns() with a buffer that becomes invalid mid-iteration + * (after several successful writes), combined with mount namespace + * destruction to test RCU cleanup logic. + */ +TEST(listns_late_fault_with_ns_cleanup) +{ + void *map; + __u64 *ns_ids; + ssize_t ret; + long page_size; + pid_t pid, iter_pid; + int pidfds[10]; + int sv[10][2]; + int iter_pidfd; + int i, status; + char c; + + page_size = sysconf(_SC_PAGESIZE); + ASSERT_GT(page_size, 0); + + /* Map two pages */ + map = mmap(NULL, page_size * 2, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + ASSERT_NE(map, MAP_FAILED); + + /* Unmap the second page */ + ret = munmap((char *)map + page_size, page_size); + ASSERT_EQ(ret, 0); + + /* + * Position buffer so we can write several u64s successfully + * before hitting the page boundary. + */ + ns_ids = ((__u64 *)((char *)map + page_size)) - 5; + + /* + * Create a separate process to run listns() concurrently. + */ + iter_pid = create_child(&iter_pidfd, 0); + ASSERT_NE(iter_pid, -1); + + if (iter_pid == 0) { + struct ns_id_req req = { + .size = sizeof(req), + .spare = 0, + .ns_id = 0, + .ns_type = 0, + .spare2 = 0, + .user_ns_id = 0, + }; + int iter_ret; + + /* + * Loop calling listns() until killed. + * Request 10 namespace IDs while namespaces are being destroyed. + * This tests: + * 1. EFAULT handling when buffer becomes invalid + * 2. Namespace cleanup outside RCU read lock during iteration + */ + while (1) { + iter_ret = sys_listns(&req, ns_ids, 10, 0); + + if (iter_ret == -1 && errno == ENOSYS) + _exit(PIDFD_SKIP); + } + } + + /* Small delay to let iterator start looping */ + usleep(50000); + + /* + * Create more children with mount namespaces to increase the + * likelihood that namespace cleanup happens during iteration. + */ + for (i = 0; i < 10; i++) { + /* Create socketpair for synchronization */ + ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sv[i]), 0); + + pid = create_child(&pidfds[i], CLONE_NEWNS); + ASSERT_NE(pid, -1); + + if (pid == 0) { + close(sv[i][0]); /* Close parent end */ + + if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0)) + _exit(1); + + /* Child: create tmpfs mounts */ + if (mkdir("/tmp/test_mnt1", 0755) == -1 && errno != EEXIST) + _exit(1); + if (mkdir("/tmp/test_mnt2", 0755) == -1 && errno != EEXIST) + _exit(1); + + if (mount("tmpfs", "/tmp/test_mnt1", "tmpfs", 0, NULL) == -1) + _exit(1); + if (mount("tmpfs", "/tmp/test_mnt2", "tmpfs", 0, NULL) == -1) + _exit(1); + + /* Signal parent that setup is complete */ + if (write_nointr(sv[i][1], "R", 1) != 1) + _exit(1); + + /* Wait for parent to signal us to exit */ + if (read_nointr(sv[i][1], &c, 1) != 1) + _exit(1); + + close(sv[i][1]); + _exit(0); + } + + close(sv[i][1]); /* Close child end */ + } + + /* Wait for all children to finish setup */ + for (i = 0; i < 10; i++) { + ret = read_nointr(sv[i][0], &c, 1); + ASSERT_EQ(ret, 1); + ASSERT_EQ(c, 'R'); + } + + /* Kill half the children */ + for (i = 0; i < 5; i++) + write_nointr(sv[i][0], "X", 1); + + /* Small delay to let some exit */ + usleep(10000); + + /* Kill remaining children */ + for (i = 5; i < 10; i++) + write_nointr(sv[i][0], "X", 1); + + /* Wait for all children and cleanup */ + for (i = 0; i < 10; i++) { + waitpid(-1, NULL, 0); + close(sv[i][0]); + close(pidfds[i]); + } + + /* Kill iterator and wait for it */ + sys_pidfd_send_signal(iter_pidfd, SIGKILL, NULL, 0); + ret = waitpid(iter_pid, &status, 0); + ASSERT_EQ(ret, iter_pid); + close(iter_pidfd); + + /* Should have been killed */ + ASSERT_TRUE(WIFSIGNALED(status)); + ASSERT_EQ(WTERMSIG(status), SIGKILL); + + /* Clean up */ + munmap(map, page_size); +} + +/* + * Test specifically focused on mount namespace cleanup during EFAULT. + * Filter for mount namespaces only. + */ +TEST(listns_mnt_ns_cleanup_on_fault) +{ + void *map; + __u64 *ns_ids; + ssize_t ret; + long page_size; + pid_t pid, iter_pid; + int pidfds[8]; + int sv[8][2]; + int iter_pidfd; + int i, status; + char c; + + page_size = sysconf(_SC_PAGESIZE); + ASSERT_GT(page_size, 0); + + /* Set up partial fault buffer */ + map = mmap(NULL, page_size * 2, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + ASSERT_NE(map, MAP_FAILED); + + ret = munmap((char *)map + page_size, page_size); + ASSERT_EQ(ret, 0); + + /* Position for 3 successful writes, then fault */ + ns_ids = ((__u64 *)((char *)map + page_size)) - 3; + + /* + * Create a separate process to run listns() concurrently. + */ + iter_pid = create_child(&iter_pidfd, 0); + ASSERT_NE(iter_pid, -1); + + if (iter_pid == 0) { + struct ns_id_req req = { + .size = sizeof(req), + .spare = 0, + .ns_id = 0, + .ns_type = CLONE_NEWNS, /* Only mount namespaces */ + .spare2 = 0, + .user_ns_id = 0, + }; + int iter_ret; + + /* + * Loop calling listns() until killed. + * Call listns() to race with namespace destruction. + */ + while (1) { + iter_ret = sys_listns(&req, ns_ids, 10, 0); + + if (iter_ret == -1 && errno == ENOSYS) + _exit(PIDFD_SKIP); + } + } + + /* Small delay to let iterator start looping */ + usleep(50000); + + /* Create children with mount namespaces */ + for (i = 0; i < 8; i++) { + /* Create socketpair for synchronization */ + ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sv[i]), 0); + + pid = create_child(&pidfds[i], CLONE_NEWNS); + ASSERT_NE(pid, -1); + + if (pid == 0) { + close(sv[i][0]); /* Close parent end */ + + if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0)) + _exit(1); + + /* Do some mount operations to make cleanup more interesting */ + if (mkdir("/tmp/test_mnt1", 0755) == -1 && errno != EEXIST) + _exit(1); + if (mkdir("/tmp/test_mnt2", 0755) == -1 && errno != EEXIST) + _exit(1); + + if (mount("tmpfs", "/tmp/test_mnt1", "tmpfs", 0, NULL) == -1) + _exit(1); + if (mount("tmpfs", "/tmp/test_mnt2", "tmpfs", 0, NULL) == -1) + _exit(1); + + /* Signal parent that setup is complete */ + if (write_nointr(sv[i][1], "R", 1) != 1) + _exit(1); + + /* Wait for parent to signal us to exit */ + if (read_nointr(sv[i][1], &c, 1) != 1) + _exit(1); + + close(sv[i][1]); + _exit(0); + } + + close(sv[i][1]); /* Close child end */ + } + + /* Wait for all children to finish setup */ + for (i = 0; i < 8; i++) { + ret = read_nointr(sv[i][0], &c, 1); + ASSERT_EQ(ret, 1); + ASSERT_EQ(c, 'R'); + } + + /* Kill children to trigger namespace destruction during iteration */ + for (i = 0; i < 8; i++) + write_nointr(sv[i][0], "X", 1); + + /* Wait for children and cleanup */ + for (i = 0; i < 8; i++) { + waitpid(-1, NULL, 0); + close(sv[i][0]); + close(pidfds[i]); + } + + /* Kill iterator and wait for it */ + sys_pidfd_send_signal(iter_pidfd, SIGKILL, NULL, 0); + ret = waitpid(iter_pid, &status, 0); + ASSERT_EQ(ret, iter_pid); + close(iter_pidfd); + + /* Should have been killed */ + ASSERT_TRUE(WIFSIGNALED(status)); + ASSERT_EQ(WTERMSIG(status), SIGKILL); + + munmap(map, page_size); +} + +TEST_HARNESS_MAIN |