mirror of
https://github.com/RGBCube/serenity
synced 2025-10-31 02:42:44 +00:00
c713e76941
We were relying on luck to make the mapping before our first mmap() be inaccessible. Let's make it explicit.
93 lines
4.9 KiB
C++
93 lines
4.9 KiB
C++
/*
|
|
* Copyright (c) 2018-2022, Andreas Kling <kling@serenityos.org>
|
|
* Copyright (c) 2021, Andrew Kaster <akaster@serenityos.org>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#include <AK/Assertions.h>
|
|
#include <AK/Format.h>
|
|
#include <AK/Types.h>
|
|
#include <LibTest/TestCase.h>
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <stdio.h>
|
|
#include <sys/mman.h>
|
|
#include <unistd.h>
|
|
|
|
#define EXPECT_OK(syscall, address, size) \
|
|
do { \
|
|
errno = 0; \
|
|
rc = syscall(fd, (void*)(address), (size_t)(size)); \
|
|
EXPECT(rc >= 0); \
|
|
if (rc < 0) { \
|
|
warnln("Expected success: " #syscall "({:p}, {}), got rc={}, errno={}", (void*)(address), (size_t)(size), rc, errno); \
|
|
} \
|
|
} while (0)
|
|
|
|
#define EXPECT_EFAULT(syscall, address, size) \
|
|
do { \
|
|
errno = 0; \
|
|
rc = syscall(fd, (void*)(address), (size_t)(size)); \
|
|
EXPECT(rc < 0); \
|
|
EXPECT_EQ(errno, EFAULT); \
|
|
if (rc >= 0 || errno != EFAULT) { \
|
|
warnln("Expected EFAULT: " #syscall "({:p}, {}), got rc={}, errno={}", (void*)(address), (size_t)(size), rc, errno); \
|
|
} \
|
|
} while (0)
|
|
|
|
TEST_CASE(test_efault)
|
|
{
|
|
int fd = open("/dev/zero", O_RDONLY);
|
|
int rc = -1;
|
|
|
|
// Make an inaccessible hole before the next mapping.
|
|
(void)mmap(nullptr, 4096, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
|
|
|
|
// Test a one-page mapping (4KB)
|
|
u8* one_page = (u8*)mmap(nullptr, 4096, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
|
|
VERIFY(one_page);
|
|
EXPECT_OK(read, one_page, 4096);
|
|
EXPECT_EFAULT(read, one_page, 4097);
|
|
EXPECT_EFAULT(read, one_page - 1, 4096);
|
|
|
|
// Make an unused hole mapping to create some inaccessible distance between our one and two-page mappings.
|
|
(void)mmap(nullptr, 16384, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
|
|
|
|
// Test a two-page mapping (8KB)
|
|
u8* two_page = (u8*)mmap(nullptr, 8192, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
|
|
VERIFY(two_page);
|
|
|
|
EXPECT_OK(read, two_page, 4096);
|
|
EXPECT_OK(read, two_page + 4096, 4096);
|
|
EXPECT_OK(read, two_page, 8192);
|
|
EXPECT_OK(read, two_page + 4095, 4097);
|
|
EXPECT_OK(read, two_page + 1, 8191);
|
|
EXPECT_EFAULT(read, two_page, 8193);
|
|
EXPECT_EFAULT(read, two_page - 1, 1);
|
|
|
|
// Check validation of pages between the first and last address.
|
|
ptrdiff_t distance = two_page - one_page;
|
|
EXPECT_EFAULT(read, one_page, (u32)distance + 1024);
|
|
|
|
constexpr auto user_range_ceiling = (sizeof(void*) == 4 ? 0xbe000000u : 0x1ffe000000);
|
|
u8* jerk_page = nullptr;
|
|
|
|
// Test every kernel page just because.
|
|
constexpr auto kernel_range_ceiling = (sizeof(void*) == 4 ? 0xffffffffu : 0x203fffffff);
|
|
for (u64 kernel_address = user_range_ceiling; kernel_address <= kernel_range_ceiling; kernel_address += PAGE_SIZE) {
|
|
jerk_page = (u8*)mmap((void*)kernel_address, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, 0, 0);
|
|
EXPECT_EQ(jerk_page, MAP_FAILED);
|
|
EXPECT_EQ(errno, EFAULT);
|
|
}
|
|
|
|
// Test the page just below where the user VM ends.
|
|
jerk_page = (u8*)mmap((void*)(user_range_ceiling - PAGE_SIZE), PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, 0, 0);
|
|
EXPECT_EQ(jerk_page, (u8*)(user_range_ceiling - PAGE_SIZE));
|
|
|
|
EXPECT_OK(read, jerk_page, PAGE_SIZE);
|
|
EXPECT_EFAULT(read, jerk_page, PAGE_SIZE + 1);
|
|
|
|
// Test something that would wrap around the 2^32 mark.
|
|
EXPECT_EFAULT(read, jerk_page, 0x50000000);
|
|
}
|