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selftest mm/mseal read-only elf memory segment

Browse source 
Sealing read-only of elf mapping so it can't be changed by mprotect.

[jeffxu@chromium.org: style change]
  Link: https://lkml.kernel.org/r/20240416220944.2481203-2-jeffxu@chromium.org
[amer.shanawany@gmail.com: fix linker error for inline function]
  Link: https://lkml.kernel.org/r/20240420202346.546444-1-amer.shanawany@gmail.com
[jeffxu@chromium.org: fix compile warning]
  Link: https://lkml.kernel.org/r/20240420003515.345982-2-jeffxu@chromium.org
[jeffxu@chromium.org: fix arm build]
  Link: https://lkml.kernel.org/r/20240502225331.3806279-2-jeffxu@chromium.org
Link: https://lkml.kernel.org/r/20240415163527.626541-6-jeffxu@chromium.org
Signed-off-by: Jeff Xu <jeffxu@chromium.org>
Signed-off-by: Amer Al Shanawany <amer.shanawany@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Jann Horn <jannh@google.com>
Cc: Jeff Xu <jeffxu@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jorge Lucangeli Obes <jorgelo@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Stephen Röttger <sroettger@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Amer Al Shanawany <amer.shanawany@gmail.com>
Cc: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Jeff Xu 2024-04-15 16:35:24 +00:00 committed by Andrew Morton
parent c010d09900
commit a52b4f11a2
4 changed files with 275 additions and 36 deletions
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1
tools/testing/selftests/mm/.gitignore vendored
View file

@ -48,3 +48,4 @@ va_high_addr_switch
hugetlb_fault_after_madv
hugetlb_madv_vs_map
mseal_test
seal_elf

1
tools/testing/selftests/mm/Makefile
View file

@ -60,6 +60,7 @@ TEST_GEN_FILES += mrelease_test
TEST_GEN_FILES += mremap_dontunmap
TEST_GEN_FILES += mremap_test
TEST_GEN_FILES += mseal_test
TEST_GEN_FILES += seal_elf
TEST_GEN_FILES += on-fault-limit
TEST_GEN_FILES += pagemap_ioctl
TEST_GEN_FILES += thuge-gen

130
tools/testing/selftests/mm/mseal_test.c
View file

@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <linux/mman.h>
#include <sys/mman.h>
#include <stdint.h>
#include <unistd.h>
@ -12,9 +13,7 @@
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <fcntl.h>
#include <assert.h>
#include <sys/ioctl.h>
#include <sys/vfs.h>
#include <sys/stat.h>
@ -31,7 +30,7 @@
# define PKEY_DISABLE_WRITE 0x2
#endif
#ifndef PKEY_BITS_PER_KEY
#ifndef PKEY_BITS_PER_PKEY
#define PKEY_BITS_PER_PKEY 2
#endif
@ -81,7 +80,7 @@ static unsigned long get_vma_size(void *addr, int *prot)
return 0;
while (fgets(line, sizeof(line), maps)) {
if (sscanf(line, "%lx-%lx %4s", &addr_start, &addr_end, &protstr) == 3) {
if (sscanf(line, "%lx-%lx %4s", &addr_start, &addr_end, protstr) == 3) {
if (addr_start == (uintptr_t) addr) {
size = addr_end - addr_start;
if (protstr[0] == 'r')
@ -189,7 +188,6 @@ static void __write_pkey_reg(u64 pkey_reg)
asm volatile(".byte 0x0f,0x01,0xef\n\t"
: : "a" (eax), "c" (ecx), "d" (edx));
assert(pkey_reg == __read_pkey_reg());
#endif
}
@ -211,10 +209,8 @@ static u64 set_pkey_bits(u64 reg, int pkey, u64 flags)
static void set_pkey(int pkey, unsigned long pkey_value)
{
unsigned long mask = (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE);
u64 new_pkey_reg;
assert(!(pkey_value & ~mask));
new_pkey_reg = set_pkey_bits(__read_pkey_reg(), pkey, pkey_value);
__write_pkey_reg(new_pkey_reg);
}
@ -224,7 +220,6 @@ static void setup_single_address(int size, void **ptrOut)
void *ptr;
ptr = sys_mmap(NULL, size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
assert(ptr != (void *)-1);
*ptrOut = ptr;
}
@ -234,24 +229,21 @@ static void setup_single_address_rw(int size, void **ptrOut)
unsigned long mapflags = MAP_ANONYMOUS | MAP_PRIVATE;
ptr = sys_mmap(NULL, size, PROT_READ | PROT_WRITE, mapflags, -1, 0);
assert(ptr != (void *)-1);
*ptrOut = ptr;
}
static void clean_single_address(void *ptr, int size)
static int clean_single_address(void *ptr, int size)
{
int ret;
ret = munmap(ptr, size);
assert(!ret);
return ret;
}
static void seal_single_address(void *ptr, int size)
static int seal_single_address(void *ptr, int size)
{
int ret;
ret = sys_mseal(ptr, size);
assert(!ret);
return ret;
}
bool seal_support(void)
@ -290,6 +282,7 @@ static void test_seal_addseal(void)
unsigned long size = 4 * page_size;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
ret = sys_mseal(ptr, size);
FAIL_TEST_IF_FALSE(!ret);
@ -305,6 +298,7 @@ static void test_seal_unmapped_start(void)
unsigned long size = 4 * page_size;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* munmap 2 pages from ptr. */
ret = sys_munmap(ptr, 2 * page_size);
@ -332,6 +326,7 @@ static void test_seal_unmapped_middle(void)
unsigned long size = 4 * page_size;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* munmap 2 pages from ptr + page. */
ret = sys_munmap(ptr + page_size, 2 * page_size);
@ -363,6 +358,7 @@ static void test_seal_unmapped_end(void)
unsigned long size = 4 * page_size;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* unmap last 2 pages. */
ret = sys_munmap(ptr + 2 * page_size, 2 * page_size);
@ -391,6 +387,7 @@ static void test_seal_multiple_vmas(void)
unsigned long size = 4 * page_size;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* use mprotect to split the vma into 3. */
ret = sys_mprotect(ptr + page_size, 2 * page_size,
@ -421,6 +418,7 @@ static void test_seal_split_start(void)
unsigned long size = 4 * page_size;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* use mprotect to split at middle */
ret = sys_mprotect(ptr, 2 * page_size, PROT_READ | PROT_WRITE);
@ -445,6 +443,7 @@ static void test_seal_split_end(void)
unsigned long size = 4 * page_size;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* use mprotect to split at middle */
ret = sys_mprotect(ptr, 2 * page_size, PROT_READ | PROT_WRITE);
@ -469,7 +468,9 @@ static void test_seal_invalid_input(void)
int ret;
setup_single_address(8 * page_size, &ptr);
clean_single_address(ptr + 4 * page_size, 4 * page_size);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
ret = clean_single_address(ptr + 4 * page_size, 4 * page_size);
FAIL_TEST_IF_FALSE(!ret);
/* invalid flag */
ret = syscall(__NR_mseal, ptr, size, 0x20);
@ -502,6 +503,7 @@ static void test_seal_zero_length(void)
int ret;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
ret = sys_mprotect(ptr, 0, PROT_READ | PROT_WRITE);
FAIL_TEST_IF_FALSE(!ret);
@ -551,6 +553,7 @@ static void test_seal_twice(void)
unsigned long size = 4 * page_size;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
ret = sys_mseal(ptr, size);
FAIL_TEST_IF_FALSE(!ret);
@ -570,9 +573,12 @@ static void test_seal_mprotect(bool seal)
int ret;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
if (seal)
seal_single_address(ptr, size);
if (seal) {
ret = seal_single_address(ptr, size);
FAIL_TEST_IF_FALSE(!ret);
}
ret = sys_mprotect(ptr, size, PROT_READ | PROT_WRITE);
if (seal)
@ -591,9 +597,12 @@ static void test_seal_start_mprotect(bool seal)
int ret;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
if (seal)
seal_single_address(ptr, page_size);
if (seal) {
ret = seal_single_address(ptr, page_size);
FAIL_TEST_IF_FALSE(!ret);
}
/* the first page is sealed. */
ret = sys_mprotect(ptr, page_size, PROT_READ | PROT_WRITE);
@ -618,9 +627,12 @@ static void test_seal_end_mprotect(bool seal)
int ret;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
if (seal)
seal_single_address(ptr + page_size, 3 * page_size);
if (seal) {
ret = seal_single_address(ptr + page_size, 3 * page_size);
FAIL_TEST_IF_FALSE(!ret);
}
/* first page is not sealed */
ret = sys_mprotect(ptr, page_size, PROT_READ | PROT_WRITE);
@ -645,9 +657,12 @@ static void test_seal_mprotect_unalign_len(bool seal)
int ret;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
if (seal)
seal_single_address(ptr, page_size * 2 - 1);
if (seal) {
ret = seal_single_address(ptr, page_size * 2 - 1);
FAIL_TEST_IF_FALSE(!ret);
}
/* 2 pages are sealed. */
ret = sys_mprotect(ptr, page_size * 2, PROT_READ | PROT_WRITE);
@ -671,8 +686,11 @@ static void test_seal_mprotect_unalign_len_variant_2(bool seal)
int ret;
setup_single_address(size, &ptr);
if (seal)
seal_single_address(ptr, page_size * 2 + 1);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
if (seal) {
ret = seal_single_address(ptr, page_size * 2 + 1);
FAIL_TEST_IF_FALSE(!ret);
}
/* 3 pages are sealed. */
ret = sys_mprotect(ptr, page_size * 3, PROT_READ | PROT_WRITE);
@ -696,13 +714,16 @@ static void test_seal_mprotect_two_vma(bool seal)
int ret;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* use mprotect to split */
ret = sys_mprotect(ptr, page_size * 2, PROT_READ | PROT_WRITE);
FAIL_TEST_IF_FALSE(!ret);
if (seal)
seal_single_address(ptr, page_size * 4);
if (seal) {
ret = seal_single_address(ptr, page_size * 4);
FAIL_TEST_IF_FALSE(!ret);
}
ret = sys_mprotect(ptr, page_size * 2, PROT_READ | PROT_WRITE);
if (seal)
@ -728,14 +749,17 @@ static void test_seal_mprotect_two_vma_with_split(bool seal)
int ret;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* use mprotect to split as two vma. */
ret = sys_mprotect(ptr, page_size * 2, PROT_READ | PROT_WRITE);
FAIL_TEST_IF_FALSE(!ret);
/* mseal can apply across 2 vma, also split them. */
if (seal)
seal_single_address(ptr + page_size, page_size * 2);
if (seal) {
ret = seal_single_address(ptr + page_size, page_size * 2);
FAIL_TEST_IF_FALSE(!ret);
}
/* the first page is not sealed. */
ret = sys_mprotect(ptr, page_size, PROT_READ | PROT_WRITE);
@ -772,10 +796,13 @@ static void test_seal_mprotect_partial_mprotect(bool seal)
int ret;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* seal one page. */
if (seal)
seal_single_address(ptr, page_size);
if (seal) {
ret = seal_single_address(ptr, page_size);
FAIL_TEST_IF_FALSE(!ret);
}
/* mprotect first 2 page will fail, since the first page are sealed. */
ret = sys_mprotect(ptr, 2 * page_size, PROT_READ | PROT_WRITE);
@ -795,6 +822,7 @@ static void test_seal_mprotect_two_vma_with_gap(bool seal)
int ret;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* use mprotect to split. */
ret = sys_mprotect(ptr, page_size, PROT_READ | PROT_WRITE);
@ -837,6 +865,7 @@ static void test_seal_mprotect_split(bool seal)
int ret;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* use mprotect to split. */
ret = sys_mprotect(ptr, page_size, PROT_READ | PROT_WRITE);
@ -873,6 +902,7 @@ static void test_seal_mprotect_merge(bool seal)
int ret;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* use mprotect to split one page. */
ret = sys_mprotect(ptr, page_size, PROT_READ | PROT_WRITE);
@ -906,6 +936,7 @@ static void test_seal_munmap(bool seal)
int ret;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
if (seal) {
ret = sys_mseal(ptr, size);
@ -936,6 +967,7 @@ static void test_seal_munmap_two_vma(bool seal)
int ret;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* use mprotect to split */
ret = sys_mprotect(ptr, page_size * 2, PROT_READ | PROT_WRITE);
@ -976,6 +1008,7 @@ static void test_seal_munmap_vma_with_gap(bool seal)
int ret;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
ret = sys_munmap(ptr + page_size, page_size * 2);
FAIL_TEST_IF_FALSE(!ret);
@ -1007,6 +1040,7 @@ static void test_munmap_start_freed(bool seal)
int prot;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* unmap the first page. */
ret = sys_munmap(ptr, page_size);
@ -1045,6 +1079,8 @@ static void test_munmap_end_freed(bool seal)
int ret;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* unmap last page. */
ret = sys_munmap(ptr + page_size * 3, page_size);
FAIL_TEST_IF_FALSE(!ret);
@ -1074,6 +1110,8 @@ static void test_munmap_middle_freed(bool seal)
int prot;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* unmap 2 pages in the middle. */
ret = sys_munmap(ptr + page_size, page_size * 2);
FAIL_TEST_IF_FALSE(!ret);
@ -1116,6 +1154,7 @@ static void test_seal_mremap_shrink(bool seal)
void *ret2;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
if (seal) {
ret = sys_mseal(ptr, size);
@ -1144,6 +1183,7 @@ static void test_seal_mremap_expand(bool seal)
void *ret2;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* ummap last 2 pages. */
ret = sys_munmap(ptr + 2 * page_size, 2 * page_size);
FAIL_TEST_IF_FALSE(!ret);
@ -1175,8 +1215,11 @@ static void test_seal_mremap_move(bool seal)
void *ret2;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
setup_single_address(size, &newPtr);
clean_single_address(newPtr, size);
FAIL_TEST_IF_FALSE(newPtr != (void *)-1);
ret = clean_single_address(newPtr, size);
FAIL_TEST_IF_FALSE(!ret);
if (seal) {
ret = sys_mseal(ptr, size);
@ -1205,6 +1248,7 @@ static void test_seal_mmap_overwrite_prot(bool seal)
void *ret2;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
if (seal) {
ret = sys_mseal(ptr, size);
@ -1232,6 +1276,7 @@ static void test_seal_mmap_expand(bool seal)
void *ret2;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* ummap last 4 pages. */
ret = sys_munmap(ptr + 8 * page_size, 4 * page_size);
FAIL_TEST_IF_FALSE(!ret);
@ -1262,6 +1307,7 @@ static void test_seal_mmap_shrink(bool seal)
void *ret2;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
if (seal) {
ret = sys_mseal(ptr, size);
@ -1290,7 +1336,9 @@ static void test_seal_mremap_shrink_fixed(bool seal)
void *ret2;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
setup_single_address(size, &newAddr);
FAIL_TEST_IF_FALSE(newAddr != (void *)-1);
if (seal) {
ret = sys_mseal(ptr, size);
@ -1319,7 +1367,9 @@ static void test_seal_mremap_expand_fixed(bool seal)
void *ret2;
setup_single_address(page_size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
setup_single_address(size, &newAddr);
FAIL_TEST_IF_FALSE(newAddr != (void *)-1);
if (seal) {
ret = sys_mseal(newAddr, size);
@ -1348,7 +1398,9 @@ static void test_seal_mremap_move_fixed(bool seal)
void *ret2;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
setup_single_address(size, &newAddr);
FAIL_TEST_IF_FALSE(newAddr != (void *)-1);
if (seal) {
ret = sys_mseal(newAddr, size);
@ -1375,6 +1427,7 @@ static void test_seal_mremap_move_fixed_zero(bool seal)
void *ret2;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
if (seal) {
ret = sys_mseal(ptr, size);
@ -1406,6 +1459,7 @@ static void test_seal_mremap_move_dontunmap(bool seal)
void *ret2;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
if (seal) {
ret = sys_mseal(ptr, size);
@ -1434,6 +1488,7 @@ static void test_seal_mremap_move_dontunmap_anyaddr(bool seal)
void *ret2;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
if (seal) {
ret = sys_mseal(ptr, size);
@ -1469,6 +1524,7 @@ static void test_seal_merge_and_split(void)
/* (24 RO) */
setup_single_address(24 * page_size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
/* use mprotect(NONE) to set out boundary */
/* (1 NONE) (22 RO) (1 NONE) */
@ -1700,9 +1756,12 @@ static void test_seal_discard_ro_anon(bool seal)
int ret;
setup_single_address(size, &ptr);
FAIL_TEST_IF_FALSE(ptr != (void *)-1);
if (seal)
seal_single_address(ptr, size);
if (seal) {
ret = seal_single_address(ptr, size);
FAIL_TEST_IF_FALSE(!ret);
}
ret = sys_madvise(ptr, size, MADV_DONTNEED);
if (seal)
@ -1832,5 +1891,4 @@ int main(int argc, char **argv)
test_seal_discard_ro_anon_on_pkey(true);
ksft_finished();
return 0;
}

179
tools/testing/selftests/mm/seal_elf.c Normal file
View file

@ -0,0 +1,179 @@
// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <sys/mman.h>
#include <stdint.h>
#include <unistd.h>
#include <string.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <stdbool.h>
#include "../kselftest.h"
#include <syscall.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/vfs.h>
#include <sys/stat.h>
/*
* need those definition for manually build using gcc.
* gcc -I ../../../../usr/include -DDEBUG -O3 -DDEBUG -O3 seal_elf.c -o seal_elf
*/
#define FAIL_TEST_IF_FALSE(c) do {\
if (!(c)) {\
ksft_test_result_fail("%s, line:%d\n", __func__, __LINE__);\
goto test_end;\
} \
} \
while (0)
#define SKIP_TEST_IF_FALSE(c) do {\
if (!(c)) {\
ksft_test_result_skip("%s, line:%d\n", __func__, __LINE__);\
goto test_end;\
} \
} \
while (0)
#define TEST_END_CHECK() {\
ksft_test_result_pass("%s\n", __func__);\
return;\
test_end:\
return;\
}
#ifndef u64
#define u64 unsigned long long
#endif
/*
* define sys_xyx to call syscall directly.
*/
static int sys_mseal(void *start, size_t len)
{
int sret;
errno = 0;
sret = syscall(__NR_mseal, start, len, 0);
return sret;
}
static void *sys_mmap(void *addr, unsigned long len, unsigned long prot,
unsigned long flags, unsigned long fd, unsigned long offset)
{
void *sret;
errno = 0;
sret = (void *) syscall(__NR_mmap, addr, len, prot,
flags, fd, offset);
return sret;
}
static inline int sys_mprotect(void *ptr, size_t size, unsigned long prot)
{
int sret;
errno = 0;
sret = syscall(__NR_mprotect, ptr, size, prot);
return sret;
}
static bool seal_support(void)
{
int ret;
void *ptr;
unsigned long page_size = getpagesize();
ptr = sys_mmap(NULL, page_size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
if (ptr == (void *) -1)
return false;
ret = sys_mseal(ptr, page_size);
if (ret < 0)
return false;
return true;
}
const char somestr[4096] = {"READONLY"};
static void test_seal_elf(void)
{
int ret;
FILE *maps;
char line[512];
uintptr_t addr_start, addr_end;
char prot[5];
char filename[256];
unsigned long page_size = getpagesize();
unsigned long long ptr = (unsigned long long) somestr;
char *somestr2 = (char *)somestr;
/*
* Modify the protection of readonly somestr
*/
if (((unsigned long long)ptr % page_size) != 0)
ptr = (unsigned long long)ptr & ~(page_size - 1);
ksft_print_msg("somestr = %s\n", somestr);
ksft_print_msg("change protection to rw\n");
ret = sys_mprotect((void *)ptr, page_size, PROT_READ|PROT_WRITE);
FAIL_TEST_IF_FALSE(!ret);
*somestr2 = 'A';
ksft_print_msg("somestr is modified to: %s\n", somestr);
ret = sys_mprotect((void *)ptr, page_size, PROT_READ);
FAIL_TEST_IF_FALSE(!ret);
maps = fopen("/proc/self/maps", "r");
FAIL_TEST_IF_FALSE(maps);
/*
* apply sealing to elf binary
*/
while (fgets(line, sizeof(line), maps)) {
if (sscanf(line, "%lx-%lx %4s %*x %*x:%*x %*u %255[^\n]",
&addr_start, &addr_end, prot, filename) == 4) {
if (strlen(filename)) {
/*
* seal the mapping if read only.
*/
if (strstr(prot, "r-")) {
ret = sys_mseal((void *)addr_start, addr_end - addr_start);
FAIL_TEST_IF_FALSE(!ret);
ksft_print_msg("sealed: %lx-%lx %s %s\n",
addr_start, addr_end, prot, filename);
if ((uintptr_t) somestr >= addr_start &&
(uintptr_t) somestr <= addr_end)
ksft_print_msg("mapping for somestr found\n");
}
}
}
}
fclose(maps);
ret = sys_mprotect((void *)ptr, page_size, PROT_READ | PROT_WRITE);
FAIL_TEST_IF_FALSE(ret < 0);
ksft_print_msg("somestr is sealed, mprotect is rejected\n");
TEST_END_CHECK();
}
int main(int argc, char **argv)
{
bool test_seal = seal_support();
ksft_print_header();
ksft_print_msg("pid=%d\n", getpid());
if (!test_seal)
ksft_exit_skip("sealing not supported, check CONFIG_64BIT\n");
ksft_set_plan(1);
test_seal_elf();
ksft_finished();
}