1244 lines
33 KiB
C
1244 lines
33 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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#define _GNU_SOURCE
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#include "../kselftest_harness.h"
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#include <asm-generic/mman.h> /* Force the import of the tools version. */
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#include <assert.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <linux/userfaultfd.h>
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#include <setjmp.h>
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#include <signal.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/ioctl.h>
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#include <sys/mman.h>
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#include <sys/syscall.h>
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#include <sys/uio.h>
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#include <unistd.h>
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/*
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* Ignore the checkpatch warning, as per the C99 standard, section 7.14.1.1:
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*
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* "If the signal occurs other than as the result of calling the abort or raise
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* function, the behavior is undefined if the signal handler refers to any
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* object with static storage duration other than by assigning a value to an
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* object declared as volatile sig_atomic_t"
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*/
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static volatile sig_atomic_t signal_jump_set;
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static sigjmp_buf signal_jmp_buf;
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/*
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* Ignore the checkpatch warning, we must read from x but don't want to do
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* anything with it in order to trigger a read page fault. We therefore must use
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* volatile to stop the compiler from optimising this away.
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*/
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#define FORCE_READ(x) (*(volatile typeof(x) *)x)
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static int userfaultfd(int flags)
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{
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return syscall(SYS_userfaultfd, flags);
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}
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static void handle_fatal(int c)
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{
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if (!signal_jump_set)
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return;
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siglongjmp(signal_jmp_buf, c);
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}
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static int pidfd_open(pid_t pid, unsigned int flags)
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{
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return syscall(SYS_pidfd_open, pid, flags);
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}
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/*
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* Enable our signal catcher and try to read/write the specified buffer. The
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* return value indicates whether the read/write succeeds without a fatal
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* signal.
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*/
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static bool try_access_buf(char *ptr, bool write)
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{
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bool failed;
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/* Tell signal handler to jump back here on fatal signal. */
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signal_jump_set = true;
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/* If a fatal signal arose, we will jump back here and failed is set. */
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failed = sigsetjmp(signal_jmp_buf, 0) != 0;
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if (!failed) {
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if (write)
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*ptr = 'x';
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else
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FORCE_READ(ptr);
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}
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signal_jump_set = false;
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return !failed;
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}
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/* Try and read from a buffer, return true if no fatal signal. */
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static bool try_read_buf(char *ptr)
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{
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return try_access_buf(ptr, false);
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}
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/* Try and write to a buffer, return true if no fatal signal. */
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static bool try_write_buf(char *ptr)
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{
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return try_access_buf(ptr, true);
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}
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/*
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* Try and BOTH read from AND write to a buffer, return true if BOTH operations
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* succeed.
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*/
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static bool try_read_write_buf(char *ptr)
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{
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return try_read_buf(ptr) && try_write_buf(ptr);
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}
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FIXTURE(guard_pages)
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{
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unsigned long page_size;
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};
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FIXTURE_SETUP(guard_pages)
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{
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struct sigaction act = {
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.sa_handler = &handle_fatal,
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.sa_flags = SA_NODEFER,
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};
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sigemptyset(&act.sa_mask);
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if (sigaction(SIGSEGV, &act, NULL))
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ksft_exit_fail_perror("sigaction");
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self->page_size = (unsigned long)sysconf(_SC_PAGESIZE);
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};
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FIXTURE_TEARDOWN(guard_pages)
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{
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struct sigaction act = {
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.sa_handler = SIG_DFL,
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.sa_flags = SA_NODEFER,
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};
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sigemptyset(&act.sa_mask);
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sigaction(SIGSEGV, &act, NULL);
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}
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TEST_F(guard_pages, basic)
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{
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const unsigned long NUM_PAGES = 10;
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const unsigned long page_size = self->page_size;
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char *ptr;
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int i;
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ptr = mmap(NULL, NUM_PAGES * page_size, PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_ANON, -1, 0);
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ASSERT_NE(ptr, MAP_FAILED);
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/* Trivially assert we can touch the first page. */
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ASSERT_TRUE(try_read_write_buf(ptr));
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ASSERT_EQ(madvise(ptr, page_size, MADV_GUARD_INSTALL), 0);
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/* Establish that 1st page SIGSEGV's. */
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ASSERT_FALSE(try_read_write_buf(ptr));
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/* Ensure we can touch everything else.*/
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for (i = 1; i < NUM_PAGES; i++) {
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char *curr = &ptr[i * page_size];
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ASSERT_TRUE(try_read_write_buf(curr));
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}
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/* Establish a guard page at the end of the mapping. */
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ASSERT_EQ(madvise(&ptr[(NUM_PAGES - 1) * page_size], page_size,
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MADV_GUARD_INSTALL), 0);
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/* Check that both guard pages result in SIGSEGV. */
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ASSERT_FALSE(try_read_write_buf(ptr));
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ASSERT_FALSE(try_read_write_buf(&ptr[(NUM_PAGES - 1) * page_size]));
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/* Remove the first guard page. */
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ASSERT_FALSE(madvise(ptr, page_size, MADV_GUARD_REMOVE));
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/* Make sure we can touch it. */
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ASSERT_TRUE(try_read_write_buf(ptr));
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/* Remove the last guard page. */
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ASSERT_FALSE(madvise(&ptr[(NUM_PAGES - 1) * page_size], page_size,
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MADV_GUARD_REMOVE));
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/* Make sure we can touch it. */
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ASSERT_TRUE(try_read_write_buf(&ptr[(NUM_PAGES - 1) * page_size]));
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/*
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* Test setting a _range_ of pages, namely the first 3. The first of
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* these be faulted in, so this also tests that we can install guard
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* pages over backed pages.
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*/
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ASSERT_EQ(madvise(ptr, 3 * page_size, MADV_GUARD_INSTALL), 0);
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/* Make sure they are all guard pages. */
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for (i = 0; i < 3; i++) {
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char *curr = &ptr[i * page_size];
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ASSERT_FALSE(try_read_write_buf(curr));
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}
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/* Make sure the rest are not. */
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for (i = 3; i < NUM_PAGES; i++) {
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char *curr = &ptr[i * page_size];
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ASSERT_TRUE(try_read_write_buf(curr));
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}
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/* Remove guard pages. */
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ASSERT_EQ(madvise(ptr, NUM_PAGES * page_size, MADV_GUARD_REMOVE), 0);
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/* Now make sure we can touch everything. */
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for (i = 0; i < NUM_PAGES; i++) {
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char *curr = &ptr[i * page_size];
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ASSERT_TRUE(try_read_write_buf(curr));
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}
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/*
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* Now remove all guard pages, make sure we don't remove existing
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* entries.
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*/
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ASSERT_EQ(madvise(ptr, NUM_PAGES * page_size, MADV_GUARD_REMOVE), 0);
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for (i = 0; i < NUM_PAGES * page_size; i += page_size) {
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char chr = ptr[i];
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ASSERT_EQ(chr, 'x');
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}
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ASSERT_EQ(munmap(ptr, NUM_PAGES * page_size), 0);
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}
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/* Assert that operations applied across multiple VMAs work as expected. */
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TEST_F(guard_pages, multi_vma)
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{
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const unsigned long page_size = self->page_size;
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char *ptr_region, *ptr, *ptr1, *ptr2, *ptr3;
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int i;
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/* Reserve a 100 page region over which we can install VMAs. */
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ptr_region = mmap(NULL, 100 * page_size, PROT_NONE,
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MAP_ANON | MAP_PRIVATE, -1, 0);
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ASSERT_NE(ptr_region, MAP_FAILED);
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/* Place a VMA of 10 pages size at the start of the region. */
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ptr1 = mmap(ptr_region, 10 * page_size, PROT_READ | PROT_WRITE,
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MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
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ASSERT_NE(ptr1, MAP_FAILED);
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/* Place a VMA of 5 pages size 50 pages into the region. */
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ptr2 = mmap(&ptr_region[50 * page_size], 5 * page_size,
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PROT_READ | PROT_WRITE,
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MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
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ASSERT_NE(ptr2, MAP_FAILED);
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/* Place a VMA of 20 pages size at the end of the region. */
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ptr3 = mmap(&ptr_region[80 * page_size], 20 * page_size,
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PROT_READ | PROT_WRITE,
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MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
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ASSERT_NE(ptr3, MAP_FAILED);
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/* Unmap gaps. */
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ASSERT_EQ(munmap(&ptr_region[10 * page_size], 40 * page_size), 0);
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ASSERT_EQ(munmap(&ptr_region[55 * page_size], 25 * page_size), 0);
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/*
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* We end up with VMAs like this:
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*
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* 0 10 .. 50 55 .. 80 100
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* [---] [---] [---]
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*/
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/*
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* Now mark the whole range as guard pages and make sure all VMAs are as
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* such.
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*/
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/*
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* madvise() is certifiable and lets you perform operations over gaps,
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* everything works, but it indicates an error and errno is set to
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* -ENOMEM. Also if anything runs out of memory it is set to
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* -ENOMEM. You are meant to guess which is which.
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*/
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ASSERT_EQ(madvise(ptr_region, 100 * page_size, MADV_GUARD_INSTALL), -1);
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ASSERT_EQ(errno, ENOMEM);
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for (i = 0; i < 10; i++) {
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char *curr = &ptr1[i * page_size];
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ASSERT_FALSE(try_read_write_buf(curr));
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}
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for (i = 0; i < 5; i++) {
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char *curr = &ptr2[i * page_size];
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ASSERT_FALSE(try_read_write_buf(curr));
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}
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for (i = 0; i < 20; i++) {
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char *curr = &ptr3[i * page_size];
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ASSERT_FALSE(try_read_write_buf(curr));
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}
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/* Now remove guar pages over range and assert the opposite. */
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ASSERT_EQ(madvise(ptr_region, 100 * page_size, MADV_GUARD_REMOVE), -1);
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ASSERT_EQ(errno, ENOMEM);
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for (i = 0; i < 10; i++) {
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char *curr = &ptr1[i * page_size];
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ASSERT_TRUE(try_read_write_buf(curr));
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}
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for (i = 0; i < 5; i++) {
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char *curr = &ptr2[i * page_size];
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ASSERT_TRUE(try_read_write_buf(curr));
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}
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for (i = 0; i < 20; i++) {
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char *curr = &ptr3[i * page_size];
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ASSERT_TRUE(try_read_write_buf(curr));
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}
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/* Now map incompatible VMAs in the gaps. */
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ptr = mmap(&ptr_region[10 * page_size], 40 * page_size,
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PROT_READ | PROT_WRITE | PROT_EXEC,
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MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
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ASSERT_NE(ptr, MAP_FAILED);
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ptr = mmap(&ptr_region[55 * page_size], 25 * page_size,
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PROT_READ | PROT_WRITE | PROT_EXEC,
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MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
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ASSERT_NE(ptr, MAP_FAILED);
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/*
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* We end up with VMAs like this:
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*
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* 0 10 .. 50 55 .. 80 100
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* [---][xxxx][---][xxxx][---]
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*
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* Where 'x' signifies VMAs that cannot be merged with those adjacent to
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* them.
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*/
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/* Multiple VMAs adjacent to one another should result in no error. */
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ASSERT_EQ(madvise(ptr_region, 100 * page_size, MADV_GUARD_INSTALL), 0);
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for (i = 0; i < 100; i++) {
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char *curr = &ptr_region[i * page_size];
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ASSERT_FALSE(try_read_write_buf(curr));
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}
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ASSERT_EQ(madvise(ptr_region, 100 * page_size, MADV_GUARD_REMOVE), 0);
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for (i = 0; i < 100; i++) {
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char *curr = &ptr_region[i * page_size];
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ASSERT_TRUE(try_read_write_buf(curr));
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}
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/* Cleanup. */
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ASSERT_EQ(munmap(ptr_region, 100 * page_size), 0);
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}
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/*
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* Assert that batched operations performed using process_madvise() work as
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* expected.
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*/
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TEST_F(guard_pages, process_madvise)
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{
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const unsigned long page_size = self->page_size;
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pid_t pid = getpid();
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int pidfd = pidfd_open(pid, 0);
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char *ptr_region, *ptr1, *ptr2, *ptr3;
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ssize_t count;
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struct iovec vec[6];
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ASSERT_NE(pidfd, -1);
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/* Reserve region to map over. */
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ptr_region = mmap(NULL, 100 * page_size, PROT_NONE,
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MAP_ANON | MAP_PRIVATE, -1, 0);
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ASSERT_NE(ptr_region, MAP_FAILED);
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/*
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* 10 pages offset 1 page into reserve region. We MAP_POPULATE so we
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* overwrite existing entries and test this code path against
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* overwriting existing entries.
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*/
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ptr1 = mmap(&ptr_region[page_size], 10 * page_size,
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PROT_READ | PROT_WRITE,
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MAP_FIXED | MAP_ANON | MAP_PRIVATE | MAP_POPULATE, -1, 0);
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ASSERT_NE(ptr1, MAP_FAILED);
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/* We want guard markers at start/end of each VMA. */
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vec[0].iov_base = ptr1;
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vec[0].iov_len = page_size;
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vec[1].iov_base = &ptr1[9 * page_size];
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vec[1].iov_len = page_size;
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/* 5 pages offset 50 pages into reserve region. */
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ptr2 = mmap(&ptr_region[50 * page_size], 5 * page_size,
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PROT_READ | PROT_WRITE,
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MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
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ASSERT_NE(ptr2, MAP_FAILED);
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vec[2].iov_base = ptr2;
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vec[2].iov_len = page_size;
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vec[3].iov_base = &ptr2[4 * page_size];
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vec[3].iov_len = page_size;
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/* 20 pages offset 79 pages into reserve region. */
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ptr3 = mmap(&ptr_region[79 * page_size], 20 * page_size,
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PROT_READ | PROT_WRITE,
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MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
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ASSERT_NE(ptr3, MAP_FAILED);
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vec[4].iov_base = ptr3;
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vec[4].iov_len = page_size;
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vec[5].iov_base = &ptr3[19 * page_size];
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vec[5].iov_len = page_size;
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/* Free surrounding VMAs. */
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ASSERT_EQ(munmap(ptr_region, page_size), 0);
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ASSERT_EQ(munmap(&ptr_region[11 * page_size], 39 * page_size), 0);
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ASSERT_EQ(munmap(&ptr_region[55 * page_size], 24 * page_size), 0);
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ASSERT_EQ(munmap(&ptr_region[99 * page_size], page_size), 0);
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/* Now guard in one step. */
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count = process_madvise(pidfd, vec, 6, MADV_GUARD_INSTALL, 0);
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/* OK we don't have permission to do this, skip. */
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if (count == -1 && errno == EPERM)
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ksft_exit_skip("No process_madvise() permissions, try running as root.\n");
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/* Returns the number of bytes advised. */
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ASSERT_EQ(count, 6 * page_size);
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/* Now make sure the guarding was applied. */
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ASSERT_FALSE(try_read_write_buf(ptr1));
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ASSERT_FALSE(try_read_write_buf(&ptr1[9 * page_size]));
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ASSERT_FALSE(try_read_write_buf(ptr2));
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ASSERT_FALSE(try_read_write_buf(&ptr2[4 * page_size]));
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ASSERT_FALSE(try_read_write_buf(ptr3));
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ASSERT_FALSE(try_read_write_buf(&ptr3[19 * page_size]));
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/* Now do the same with unguard... */
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count = process_madvise(pidfd, vec, 6, MADV_GUARD_REMOVE, 0);
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/* ...and everything should now succeed. */
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ASSERT_TRUE(try_read_write_buf(ptr1));
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ASSERT_TRUE(try_read_write_buf(&ptr1[9 * page_size]));
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ASSERT_TRUE(try_read_write_buf(ptr2));
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ASSERT_TRUE(try_read_write_buf(&ptr2[4 * page_size]));
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ASSERT_TRUE(try_read_write_buf(ptr3));
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ASSERT_TRUE(try_read_write_buf(&ptr3[19 * page_size]));
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/* Cleanup. */
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ASSERT_EQ(munmap(ptr1, 10 * page_size), 0);
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ASSERT_EQ(munmap(ptr2, 5 * page_size), 0);
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ASSERT_EQ(munmap(ptr3, 20 * page_size), 0);
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close(pidfd);
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}
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/* Assert that unmapping ranges does not leave guard markers behind. */
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TEST_F(guard_pages, munmap)
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{
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const unsigned long page_size = self->page_size;
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char *ptr, *ptr_new1, *ptr_new2;
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ptr = mmap(NULL, 10 * page_size, PROT_READ | PROT_WRITE,
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MAP_ANON | MAP_PRIVATE, -1, 0);
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ASSERT_NE(ptr, MAP_FAILED);
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/* Guard first and last pages. */
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ASSERT_EQ(madvise(ptr, page_size, MADV_GUARD_INSTALL), 0);
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ASSERT_EQ(madvise(&ptr[9 * page_size], page_size, MADV_GUARD_INSTALL), 0);
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/* Assert that they are guarded. */
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ASSERT_FALSE(try_read_write_buf(ptr));
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ASSERT_FALSE(try_read_write_buf(&ptr[9 * page_size]));
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/* Unmap them. */
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ASSERT_EQ(munmap(ptr, page_size), 0);
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ASSERT_EQ(munmap(&ptr[9 * page_size], page_size), 0);
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/* Map over them.*/
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ptr_new1 = mmap(ptr, page_size, PROT_READ | PROT_WRITE,
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MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr_new1, MAP_FAILED);
|
|
ptr_new2 = mmap(&ptr[9 * page_size], page_size, PROT_READ | PROT_WRITE,
|
|
MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr_new2, MAP_FAILED);
|
|
|
|
/* Assert that they are now not guarded. */
|
|
ASSERT_TRUE(try_read_write_buf(ptr_new1));
|
|
ASSERT_TRUE(try_read_write_buf(ptr_new2));
|
|
|
|
/* Cleanup. */
|
|
ASSERT_EQ(munmap(ptr, 10 * page_size), 0);
|
|
}
|
|
|
|
/* Assert that mprotect() operations have no bearing on guard markers. */
|
|
TEST_F(guard_pages, mprotect)
|
|
{
|
|
const unsigned long page_size = self->page_size;
|
|
char *ptr;
|
|
int i;
|
|
|
|
ptr = mmap(NULL, 10 * page_size, PROT_READ | PROT_WRITE,
|
|
MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr, MAP_FAILED);
|
|
|
|
/* Guard the middle of the range. */
|
|
ASSERT_EQ(madvise(&ptr[5 * page_size], 2 * page_size,
|
|
MADV_GUARD_INSTALL), 0);
|
|
|
|
/* Assert that it is indeed guarded. */
|
|
ASSERT_FALSE(try_read_write_buf(&ptr[5 * page_size]));
|
|
ASSERT_FALSE(try_read_write_buf(&ptr[6 * page_size]));
|
|
|
|
/* Now make these pages read-only. */
|
|
ASSERT_EQ(mprotect(&ptr[5 * page_size], 2 * page_size, PROT_READ), 0);
|
|
|
|
/* Make sure the range is still guarded. */
|
|
ASSERT_FALSE(try_read_buf(&ptr[5 * page_size]));
|
|
ASSERT_FALSE(try_read_buf(&ptr[6 * page_size]));
|
|
|
|
/* Make sure we can guard again without issue.*/
|
|
ASSERT_EQ(madvise(&ptr[5 * page_size], 2 * page_size,
|
|
MADV_GUARD_INSTALL), 0);
|
|
|
|
/* Make sure the range is, yet again, still guarded. */
|
|
ASSERT_FALSE(try_read_buf(&ptr[5 * page_size]));
|
|
ASSERT_FALSE(try_read_buf(&ptr[6 * page_size]));
|
|
|
|
/* Now unguard the whole range. */
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_GUARD_REMOVE), 0);
|
|
|
|
/* Make sure the whole range is readable. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_TRUE(try_read_buf(curr));
|
|
}
|
|
|
|
/* Cleanup. */
|
|
ASSERT_EQ(munmap(ptr, 10 * page_size), 0);
|
|
}
|
|
|
|
/* Split and merge VMAs and make sure guard pages still behave. */
|
|
TEST_F(guard_pages, split_merge)
|
|
{
|
|
const unsigned long page_size = self->page_size;
|
|
char *ptr, *ptr_new;
|
|
int i;
|
|
|
|
ptr = mmap(NULL, 10 * page_size, PROT_READ | PROT_WRITE,
|
|
MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr, MAP_FAILED);
|
|
|
|
/* Guard the whole range. */
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_GUARD_INSTALL), 0);
|
|
|
|
/* Make sure the whole range is guarded. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_FALSE(try_read_write_buf(curr));
|
|
}
|
|
|
|
/* Now unmap some pages in the range so we split. */
|
|
ASSERT_EQ(munmap(&ptr[2 * page_size], page_size), 0);
|
|
ASSERT_EQ(munmap(&ptr[5 * page_size], page_size), 0);
|
|
ASSERT_EQ(munmap(&ptr[8 * page_size], page_size), 0);
|
|
|
|
/* Make sure the remaining ranges are guarded post-split. */
|
|
for (i = 0; i < 2; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_FALSE(try_read_write_buf(curr));
|
|
}
|
|
for (i = 2; i < 5; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_FALSE(try_read_write_buf(curr));
|
|
}
|
|
for (i = 6; i < 8; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_FALSE(try_read_write_buf(curr));
|
|
}
|
|
for (i = 9; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_FALSE(try_read_write_buf(curr));
|
|
}
|
|
|
|
/* Now map them again - the unmap will have cleared the guards. */
|
|
ptr_new = mmap(&ptr[2 * page_size], page_size, PROT_READ | PROT_WRITE,
|
|
MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr_new, MAP_FAILED);
|
|
ptr_new = mmap(&ptr[5 * page_size], page_size, PROT_READ | PROT_WRITE,
|
|
MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr_new, MAP_FAILED);
|
|
ptr_new = mmap(&ptr[8 * page_size], page_size, PROT_READ | PROT_WRITE,
|
|
MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr_new, MAP_FAILED);
|
|
|
|
/* Now make sure guard pages are established. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
bool result = try_read_write_buf(curr);
|
|
bool expect_true = i == 2 || i == 5 || i == 8;
|
|
|
|
ASSERT_TRUE(expect_true ? result : !result);
|
|
}
|
|
|
|
/* Now guard everything again. */
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_GUARD_INSTALL), 0);
|
|
|
|
/* Make sure the whole range is guarded. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_FALSE(try_read_write_buf(curr));
|
|
}
|
|
|
|
/* Now split the range into three. */
|
|
ASSERT_EQ(mprotect(ptr, 3 * page_size, PROT_READ), 0);
|
|
ASSERT_EQ(mprotect(&ptr[7 * page_size], 3 * page_size, PROT_READ), 0);
|
|
|
|
/* Make sure the whole range is guarded for read. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_FALSE(try_read_buf(curr));
|
|
}
|
|
|
|
/* Now reset protection bits so we merge the whole thing. */
|
|
ASSERT_EQ(mprotect(ptr, 3 * page_size, PROT_READ | PROT_WRITE), 0);
|
|
ASSERT_EQ(mprotect(&ptr[7 * page_size], 3 * page_size,
|
|
PROT_READ | PROT_WRITE), 0);
|
|
|
|
/* Make sure the whole range is still guarded. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_FALSE(try_read_write_buf(curr));
|
|
}
|
|
|
|
/* Split range into 3 again... */
|
|
ASSERT_EQ(mprotect(ptr, 3 * page_size, PROT_READ), 0);
|
|
ASSERT_EQ(mprotect(&ptr[7 * page_size], 3 * page_size, PROT_READ), 0);
|
|
|
|
/* ...and unguard the whole range. */
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_GUARD_REMOVE), 0);
|
|
|
|
/* Make sure the whole range is remedied for read. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_TRUE(try_read_buf(curr));
|
|
}
|
|
|
|
/* Merge them again. */
|
|
ASSERT_EQ(mprotect(ptr, 3 * page_size, PROT_READ | PROT_WRITE), 0);
|
|
ASSERT_EQ(mprotect(&ptr[7 * page_size], 3 * page_size,
|
|
PROT_READ | PROT_WRITE), 0);
|
|
|
|
/* Now ensure the merged range is remedied for read/write. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_TRUE(try_read_write_buf(curr));
|
|
}
|
|
|
|
/* Cleanup. */
|
|
ASSERT_EQ(munmap(ptr, 10 * page_size), 0);
|
|
}
|
|
|
|
/* Assert that MADV_DONTNEED does not remove guard markers. */
|
|
TEST_F(guard_pages, dontneed)
|
|
{
|
|
const unsigned long page_size = self->page_size;
|
|
char *ptr;
|
|
int i;
|
|
|
|
ptr = mmap(NULL, 10 * page_size, PROT_READ | PROT_WRITE,
|
|
MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr, MAP_FAILED);
|
|
|
|
/* Back the whole range. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
*curr = 'y';
|
|
}
|
|
|
|
/* Guard every other page. */
|
|
for (i = 0; i < 10; i += 2) {
|
|
char *curr = &ptr[i * page_size];
|
|
int res = madvise(curr, page_size, MADV_GUARD_INSTALL);
|
|
|
|
ASSERT_EQ(res, 0);
|
|
}
|
|
|
|
/* Indicate that we don't need any of the range. */
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_DONTNEED), 0);
|
|
|
|
/* Check to ensure guard markers are still in place. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
bool result = try_read_buf(curr);
|
|
|
|
if (i % 2 == 0) {
|
|
ASSERT_FALSE(result);
|
|
} else {
|
|
ASSERT_TRUE(result);
|
|
/* Make sure we really did get reset to zero page. */
|
|
ASSERT_EQ(*curr, '\0');
|
|
}
|
|
|
|
/* Now write... */
|
|
result = try_write_buf(&ptr[i * page_size]);
|
|
|
|
/* ...and make sure same result. */
|
|
ASSERT_TRUE(i % 2 != 0 ? result : !result);
|
|
}
|
|
|
|
/* Cleanup. */
|
|
ASSERT_EQ(munmap(ptr, 10 * page_size), 0);
|
|
}
|
|
|
|
/* Assert that mlock()'ed pages work correctly with guard markers. */
|
|
TEST_F(guard_pages, mlock)
|
|
{
|
|
const unsigned long page_size = self->page_size;
|
|
char *ptr;
|
|
int i;
|
|
|
|
ptr = mmap(NULL, 10 * page_size, PROT_READ | PROT_WRITE,
|
|
MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr, MAP_FAILED);
|
|
|
|
/* Populate. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
*curr = 'y';
|
|
}
|
|
|
|
/* Lock. */
|
|
ASSERT_EQ(mlock(ptr, 10 * page_size), 0);
|
|
|
|
/* Now try to guard, should fail with EINVAL. */
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_GUARD_INSTALL), -1);
|
|
ASSERT_EQ(errno, EINVAL);
|
|
|
|
/* OK unlock. */
|
|
ASSERT_EQ(munlock(ptr, 10 * page_size), 0);
|
|
|
|
/* Guard first half of range, should now succeed. */
|
|
ASSERT_EQ(madvise(ptr, 5 * page_size, MADV_GUARD_INSTALL), 0);
|
|
|
|
/* Make sure guard works. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
bool result = try_read_write_buf(curr);
|
|
|
|
if (i < 5) {
|
|
ASSERT_FALSE(result);
|
|
} else {
|
|
ASSERT_TRUE(result);
|
|
ASSERT_EQ(*curr, 'x');
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Now lock the latter part of the range. We can't lock the guard pages,
|
|
* as this would result in the pages being populated and the guarding
|
|
* would cause this to error out.
|
|
*/
|
|
ASSERT_EQ(mlock(&ptr[5 * page_size], 5 * page_size), 0);
|
|
|
|
/*
|
|
* Now remove guard pages, we permit mlock()'d ranges to have guard
|
|
* pages removed as it is a non-destructive operation.
|
|
*/
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_GUARD_REMOVE), 0);
|
|
|
|
/* Now check that no guard pages remain. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_TRUE(try_read_write_buf(curr));
|
|
}
|
|
|
|
/* Cleanup. */
|
|
ASSERT_EQ(munmap(ptr, 10 * page_size), 0);
|
|
}
|
|
|
|
/*
|
|
* Assert that moving, extending and shrinking memory via mremap() retains
|
|
* guard markers where possible.
|
|
*
|
|
* - Moving a mapping alone should retain markers as they are.
|
|
*/
|
|
TEST_F(guard_pages, mremap_move)
|
|
{
|
|
const unsigned long page_size = self->page_size;
|
|
char *ptr, *ptr_new;
|
|
|
|
/* Map 5 pages. */
|
|
ptr = mmap(NULL, 5 * page_size, PROT_READ | PROT_WRITE,
|
|
MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr, MAP_FAILED);
|
|
|
|
/* Place guard markers at both ends of the 5 page span. */
|
|
ASSERT_EQ(madvise(ptr, page_size, MADV_GUARD_INSTALL), 0);
|
|
ASSERT_EQ(madvise(&ptr[4 * page_size], page_size, MADV_GUARD_INSTALL), 0);
|
|
|
|
/* Make sure the guard pages are in effect. */
|
|
ASSERT_FALSE(try_read_write_buf(ptr));
|
|
ASSERT_FALSE(try_read_write_buf(&ptr[4 * page_size]));
|
|
|
|
/* Map a new region we will move this range into. Doing this ensures
|
|
* that we have reserved a range to map into.
|
|
*/
|
|
ptr_new = mmap(NULL, 5 * page_size, PROT_NONE, MAP_ANON | MAP_PRIVATE,
|
|
-1, 0);
|
|
ASSERT_NE(ptr_new, MAP_FAILED);
|
|
|
|
ASSERT_EQ(mremap(ptr, 5 * page_size, 5 * page_size,
|
|
MREMAP_MAYMOVE | MREMAP_FIXED, ptr_new), ptr_new);
|
|
|
|
/* Make sure the guard markers are retained. */
|
|
ASSERT_FALSE(try_read_write_buf(ptr_new));
|
|
ASSERT_FALSE(try_read_write_buf(&ptr_new[4 * page_size]));
|
|
|
|
/*
|
|
* Clean up - we only need reference the new pointer as we overwrote the
|
|
* PROT_NONE range and moved the existing one.
|
|
*/
|
|
munmap(ptr_new, 5 * page_size);
|
|
}
|
|
|
|
/*
|
|
* Assert that moving, extending and shrinking memory via mremap() retains
|
|
* guard markers where possible.
|
|
*
|
|
* Expanding should retain guard pages, only now in different position. The user
|
|
* will have to remove guard pages manually to fix up (they'd have to do the
|
|
* same if it were a PROT_NONE mapping).
|
|
*/
|
|
TEST_F(guard_pages, mremap_expand)
|
|
{
|
|
const unsigned long page_size = self->page_size;
|
|
char *ptr, *ptr_new;
|
|
|
|
/* Map 10 pages... */
|
|
ptr = mmap(NULL, 10 * page_size, PROT_READ | PROT_WRITE,
|
|
MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr, MAP_FAILED);
|
|
/* ...But unmap the last 5 so we can ensure we can expand into them. */
|
|
ASSERT_EQ(munmap(&ptr[5 * page_size], 5 * page_size), 0);
|
|
|
|
/* Place guard markers at both ends of the 5 page span. */
|
|
ASSERT_EQ(madvise(ptr, page_size, MADV_GUARD_INSTALL), 0);
|
|
ASSERT_EQ(madvise(&ptr[4 * page_size], page_size, MADV_GUARD_INSTALL), 0);
|
|
|
|
/* Make sure the guarding is in effect. */
|
|
ASSERT_FALSE(try_read_write_buf(ptr));
|
|
ASSERT_FALSE(try_read_write_buf(&ptr[4 * page_size]));
|
|
|
|
/* Now expand to 10 pages. */
|
|
ptr = mremap(ptr, 5 * page_size, 10 * page_size, 0);
|
|
ASSERT_NE(ptr, MAP_FAILED);
|
|
|
|
/*
|
|
* Make sure the guard markers are retained in their original positions.
|
|
*/
|
|
ASSERT_FALSE(try_read_write_buf(ptr));
|
|
ASSERT_FALSE(try_read_write_buf(&ptr[4 * page_size]));
|
|
|
|
/* Reserve a region which we can move to and expand into. */
|
|
ptr_new = mmap(NULL, 20 * page_size, PROT_NONE,
|
|
MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr_new, MAP_FAILED);
|
|
|
|
/* Now move and expand into it. */
|
|
ptr = mremap(ptr, 10 * page_size, 20 * page_size,
|
|
MREMAP_MAYMOVE | MREMAP_FIXED, ptr_new);
|
|
ASSERT_EQ(ptr, ptr_new);
|
|
|
|
/*
|
|
* Again, make sure the guard markers are retained in their original positions.
|
|
*/
|
|
ASSERT_FALSE(try_read_write_buf(ptr));
|
|
ASSERT_FALSE(try_read_write_buf(&ptr[4 * page_size]));
|
|
|
|
/*
|
|
* A real user would have to remove guard markers, but would reasonably
|
|
* expect all characteristics of the mapping to be retained, including
|
|
* guard markers.
|
|
*/
|
|
|
|
/* Cleanup. */
|
|
munmap(ptr, 20 * page_size);
|
|
}
|
|
/*
|
|
* Assert that moving, extending and shrinking memory via mremap() retains
|
|
* guard markers where possible.
|
|
*
|
|
* Shrinking will result in markers that are shrunk over being removed. Again,
|
|
* if the user were using a PROT_NONE mapping they'd have to manually fix this
|
|
* up also so this is OK.
|
|
*/
|
|
TEST_F(guard_pages, mremap_shrink)
|
|
{
|
|
const unsigned long page_size = self->page_size;
|
|
char *ptr;
|
|
int i;
|
|
|
|
/* Map 5 pages. */
|
|
ptr = mmap(NULL, 5 * page_size, PROT_READ | PROT_WRITE,
|
|
MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr, MAP_FAILED);
|
|
|
|
/* Place guard markers at both ends of the 5 page span. */
|
|
ASSERT_EQ(madvise(ptr, page_size, MADV_GUARD_INSTALL), 0);
|
|
ASSERT_EQ(madvise(&ptr[4 * page_size], page_size, MADV_GUARD_INSTALL), 0);
|
|
|
|
/* Make sure the guarding is in effect. */
|
|
ASSERT_FALSE(try_read_write_buf(ptr));
|
|
ASSERT_FALSE(try_read_write_buf(&ptr[4 * page_size]));
|
|
|
|
/* Now shrink to 3 pages. */
|
|
ptr = mremap(ptr, 5 * page_size, 3 * page_size, MREMAP_MAYMOVE);
|
|
ASSERT_NE(ptr, MAP_FAILED);
|
|
|
|
/* We expect the guard marker at the start to be retained... */
|
|
ASSERT_FALSE(try_read_write_buf(ptr));
|
|
|
|
/* ...But remaining pages will not have guard markers. */
|
|
for (i = 1; i < 3; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_TRUE(try_read_write_buf(curr));
|
|
}
|
|
|
|
/*
|
|
* As with expansion, a real user would have to remove guard pages and
|
|
* fixup. But you'd have to do similar manual things with PROT_NONE
|
|
* mappings too.
|
|
*/
|
|
|
|
/*
|
|
* If we expand back to the original size, the end marker will, of
|
|
* course, no longer be present.
|
|
*/
|
|
ptr = mremap(ptr, 3 * page_size, 5 * page_size, 0);
|
|
ASSERT_NE(ptr, MAP_FAILED);
|
|
|
|
/* Again, we expect the guard marker at the start to be retained... */
|
|
ASSERT_FALSE(try_read_write_buf(ptr));
|
|
|
|
/* ...But remaining pages will not have guard markers. */
|
|
for (i = 1; i < 5; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_TRUE(try_read_write_buf(curr));
|
|
}
|
|
|
|
/* Cleanup. */
|
|
munmap(ptr, 5 * page_size);
|
|
}
|
|
|
|
/*
|
|
* Assert that forking a process with VMAs that do not have VM_WIPEONFORK set
|
|
* retain guard pages.
|
|
*/
|
|
TEST_F(guard_pages, fork)
|
|
{
|
|
const unsigned long page_size = self->page_size;
|
|
char *ptr;
|
|
pid_t pid;
|
|
int i;
|
|
|
|
/* Map 10 pages. */
|
|
ptr = mmap(NULL, 10 * page_size, PROT_READ | PROT_WRITE,
|
|
MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr, MAP_FAILED);
|
|
|
|
/* Establish guard apges in the first 5 pages. */
|
|
ASSERT_EQ(madvise(ptr, 5 * page_size, MADV_GUARD_INSTALL), 0);
|
|
|
|
pid = fork();
|
|
ASSERT_NE(pid, -1);
|
|
if (!pid) {
|
|
/* This is the child process now. */
|
|
|
|
/* Assert that the guarding is in effect. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
bool result = try_read_write_buf(curr);
|
|
|
|
ASSERT_TRUE(i >= 5 ? result : !result);
|
|
}
|
|
|
|
/* Now unguard the range.*/
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_GUARD_REMOVE), 0);
|
|
|
|
exit(0);
|
|
}
|
|
|
|
/* Parent process. */
|
|
|
|
/* Parent simply waits on child. */
|
|
waitpid(pid, NULL, 0);
|
|
|
|
/* Child unguard does not impact parent page table state. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
bool result = try_read_write_buf(curr);
|
|
|
|
ASSERT_TRUE(i >= 5 ? result : !result);
|
|
}
|
|
|
|
/* Cleanup. */
|
|
ASSERT_EQ(munmap(ptr, 10 * page_size), 0);
|
|
}
|
|
|
|
/*
|
|
* Assert that forking a process with VMAs that do have VM_WIPEONFORK set
|
|
* behave as expected.
|
|
*/
|
|
TEST_F(guard_pages, fork_wipeonfork)
|
|
{
|
|
const unsigned long page_size = self->page_size;
|
|
char *ptr;
|
|
pid_t pid;
|
|
int i;
|
|
|
|
/* Map 10 pages. */
|
|
ptr = mmap(NULL, 10 * page_size, PROT_READ | PROT_WRITE,
|
|
MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr, MAP_FAILED);
|
|
|
|
/* Mark wipe on fork. */
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_WIPEONFORK), 0);
|
|
|
|
/* Guard the first 5 pages. */
|
|
ASSERT_EQ(madvise(ptr, 5 * page_size, MADV_GUARD_INSTALL), 0);
|
|
|
|
pid = fork();
|
|
ASSERT_NE(pid, -1);
|
|
if (!pid) {
|
|
/* This is the child process now. */
|
|
|
|
/* Guard will have been wiped. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_TRUE(try_read_write_buf(curr));
|
|
}
|
|
|
|
exit(0);
|
|
}
|
|
|
|
/* Parent process. */
|
|
|
|
waitpid(pid, NULL, 0);
|
|
|
|
/* Guard markers should be in effect.*/
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
bool result = try_read_write_buf(curr);
|
|
|
|
ASSERT_TRUE(i >= 5 ? result : !result);
|
|
}
|
|
|
|
/* Cleanup. */
|
|
ASSERT_EQ(munmap(ptr, 10 * page_size), 0);
|
|
}
|
|
|
|
/* Ensure that MADV_FREE retains guard entries as expected. */
|
|
TEST_F(guard_pages, lazyfree)
|
|
{
|
|
const unsigned long page_size = self->page_size;
|
|
char *ptr;
|
|
int i;
|
|
|
|
/* Map 10 pages. */
|
|
ptr = mmap(NULL, 10 * page_size, PROT_READ | PROT_WRITE,
|
|
MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr, MAP_FAILED);
|
|
|
|
/* Guard range. */
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_GUARD_INSTALL), 0);
|
|
|
|
/* Ensure guarded. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_FALSE(try_read_write_buf(curr));
|
|
}
|
|
|
|
/* Lazyfree range. */
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_FREE), 0);
|
|
|
|
/* This should leave the guard markers in place. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_FALSE(try_read_write_buf(curr));
|
|
}
|
|
|
|
/* Cleanup. */
|
|
ASSERT_EQ(munmap(ptr, 10 * page_size), 0);
|
|
}
|
|
|
|
/* Ensure that MADV_POPULATE_READ, MADV_POPULATE_WRITE behave as expected. */
|
|
TEST_F(guard_pages, populate)
|
|
{
|
|
const unsigned long page_size = self->page_size;
|
|
char *ptr;
|
|
|
|
/* Map 10 pages. */
|
|
ptr = mmap(NULL, 10 * page_size, PROT_READ | PROT_WRITE,
|
|
MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr, MAP_FAILED);
|
|
|
|
/* Guard range. */
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_GUARD_INSTALL), 0);
|
|
|
|
/* Populate read should error out... */
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_POPULATE_READ), -1);
|
|
ASSERT_EQ(errno, EFAULT);
|
|
|
|
/* ...as should populate write. */
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_POPULATE_WRITE), -1);
|
|
ASSERT_EQ(errno, EFAULT);
|
|
|
|
/* Cleanup. */
|
|
ASSERT_EQ(munmap(ptr, 10 * page_size), 0);
|
|
}
|
|
|
|
/* Ensure that MADV_COLD, MADV_PAGEOUT do not remove guard markers. */
|
|
TEST_F(guard_pages, cold_pageout)
|
|
{
|
|
const unsigned long page_size = self->page_size;
|
|
char *ptr;
|
|
int i;
|
|
|
|
/* Map 10 pages. */
|
|
ptr = mmap(NULL, 10 * page_size, PROT_READ | PROT_WRITE,
|
|
MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr, MAP_FAILED);
|
|
|
|
/* Guard range. */
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_GUARD_INSTALL), 0);
|
|
|
|
/* Ensured guarded. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_FALSE(try_read_write_buf(curr));
|
|
}
|
|
|
|
/* Now mark cold. This should have no impact on guard markers. */
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_COLD), 0);
|
|
|
|
/* Should remain guarded. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_FALSE(try_read_write_buf(curr));
|
|
}
|
|
|
|
/* OK, now page out. This should equally, have no effect on markers. */
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_PAGEOUT), 0);
|
|
|
|
/* Should remain guarded. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_FALSE(try_read_write_buf(curr));
|
|
}
|
|
|
|
/* Cleanup. */
|
|
ASSERT_EQ(munmap(ptr, 10 * page_size), 0);
|
|
}
|
|
|
|
/* Ensure that guard pages do not break userfaultd. */
|
|
TEST_F(guard_pages, uffd)
|
|
{
|
|
const unsigned long page_size = self->page_size;
|
|
int uffd;
|
|
char *ptr;
|
|
int i;
|
|
struct uffdio_api api = {
|
|
.api = UFFD_API,
|
|
.features = 0,
|
|
};
|
|
struct uffdio_register reg;
|
|
struct uffdio_range range;
|
|
|
|
/* Set up uffd. */
|
|
uffd = userfaultfd(0);
|
|
if (uffd == -1 && errno == EPERM)
|
|
ksft_exit_skip("No userfaultfd permissions, try running as root.\n");
|
|
ASSERT_NE(uffd, -1);
|
|
|
|
ASSERT_EQ(ioctl(uffd, UFFDIO_API, &api), 0);
|
|
|
|
/* Map 10 pages. */
|
|
ptr = mmap(NULL, 10 * page_size, PROT_READ | PROT_WRITE,
|
|
MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
ASSERT_NE(ptr, MAP_FAILED);
|
|
|
|
/* Register the range with uffd. */
|
|
range.start = (unsigned long)ptr;
|
|
range.len = 10 * page_size;
|
|
reg.range = range;
|
|
reg.mode = UFFDIO_REGISTER_MODE_MISSING;
|
|
ASSERT_EQ(ioctl(uffd, UFFDIO_REGISTER, ®), 0);
|
|
|
|
/* Guard the range. This should not trigger the uffd. */
|
|
ASSERT_EQ(madvise(ptr, 10 * page_size, MADV_GUARD_INSTALL), 0);
|
|
|
|
/* The guarding should behave as usual with no uffd intervention. */
|
|
for (i = 0; i < 10; i++) {
|
|
char *curr = &ptr[i * page_size];
|
|
|
|
ASSERT_FALSE(try_read_write_buf(curr));
|
|
}
|
|
|
|
/* Cleanup. */
|
|
ASSERT_EQ(ioctl(uffd, UFFDIO_UNREGISTER, &range), 0);
|
|
close(uffd);
|
|
ASSERT_EQ(munmap(ptr, 10 * page_size), 0);
|
|
}
|
|
|
|
TEST_HARNESS_MAIN
|