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tools/testing/selftests/vm/map_fixed_noreplace.c: add test for MAP_FIXED_NOREPLACE

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Add a test for MAP_FIXED_NOREPLACE, based on some code originally by Jann
Horn.  This would have caught the overlap bug reported by Daniel Micay.

I originally suggested to Michal that we create MAP_FIXED_NOREPLACE, but
instead of writing a selftest I spent my time bike-shedding whether it
should be called MAP_FIXED_SAFE/NOCLOBBER/WEAK/NEW ..  mea culpa.

Link: http://lkml.kernel.org/r/20181013133929.28653-1-mpe@ellerman.id.au
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Jann Horn <jannh@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Jason Evans <jasone@google.com>
Cc: David Goldblatt <davidtgoldblatt@gmail.com>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Michael Ellerman 2018-10-26 15:10:48 -07:00 committed by Linus Torvalds
parent 7eef5f97c1
commit 91cbacc345
3 changed files with 208 additions and 0 deletions
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1
tools/testing/selftests/vm/.gitignore vendored
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@ -13,3 +13,4 @@ mlock-random-test
virtual_address_range
gup_benchmark
va_128TBswitch
map_fixed_noreplace

1
tools/testing/selftests/vm/Makefile
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@ -12,6 +12,7 @@ TEST_GEN_FILES += gup_benchmark
TEST_GEN_FILES += hugepage-mmap
TEST_GEN_FILES += hugepage-shm
TEST_GEN_FILES += map_hugetlb
TEST_GEN_FILES += map_fixed_noreplace
TEST_GEN_FILES += map_populate
TEST_GEN_FILES += mlock-random-test
TEST_GEN_FILES += mlock2-tests

206
tools/testing/selftests/vm/map_fixed_noreplace.c Normal file
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@ -0,0 +1,206 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Test that MAP_FIXED_NOREPLACE works.
*
* Copyright 2018, Jann Horn <jannh@google.com>
* Copyright 2018, Michael Ellerman, IBM Corporation.
*/
#include <sys/mman.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#ifndef MAP_FIXED_NOREPLACE
#define MAP_FIXED_NOREPLACE 0x100000
#endif
#define BASE_ADDRESS (256ul * 1024 * 1024)
static void dump_maps(void)
{
char cmd[32];
snprintf(cmd, sizeof(cmd), "cat /proc/%d/maps", getpid());
system(cmd);
}
int main(void)
{
unsigned long flags, addr, size, page_size;
char *p;
page_size = sysconf(_SC_PAGE_SIZE);
flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED_NOREPLACE;
// Check we can map all the areas we need below
errno = 0;
addr = BASE_ADDRESS;
size = 5 * page_size;
p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);
if (p == MAP_FAILED) {
dump_maps();
printf("Error: couldn't map the space we need for the test\n");
return 1;
}
errno = 0;
if (munmap((void *)addr, 5 * page_size) != 0) {
dump_maps();
printf("Error: munmap failed!?\n");
return 1;
}
printf("unmap() successful\n");
errno = 0;
addr = BASE_ADDRESS + page_size;
size = 3 * page_size;
p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);
if (p == MAP_FAILED) {
dump_maps();
printf("Error: first mmap() failed unexpectedly\n");
return 1;
}
/*
* Exact same mapping again:
* base | free | new
* +1 | mapped | new
* +2 | mapped | new
* +3 | mapped | new
* +4 | free | new
*/
errno = 0;
addr = BASE_ADDRESS;
size = 5 * page_size;
p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);
if (p != MAP_FAILED) {
dump_maps();
printf("Error:1: mmap() succeeded when it shouldn't have\n");
return 1;
}
/*
* Second mapping contained within first:
*
* base | free |
* +1 | mapped |
* +2 | mapped | new
* +3 | mapped |
* +4 | free |
*/
errno = 0;
addr = BASE_ADDRESS + (2 * page_size);
size = page_size;
p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);
if (p != MAP_FAILED) {
dump_maps();
printf("Error:2: mmap() succeeded when it shouldn't have\n");
return 1;
}
/*
* Overlap end of existing mapping:
* base | free |
* +1 | mapped |
* +2 | mapped |
* +3 | mapped | new
* +4 | free | new
*/
errno = 0;
addr = BASE_ADDRESS + (3 * page_size);
size = 2 * page_size;
p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);
if (p != MAP_FAILED) {
dump_maps();
printf("Error:3: mmap() succeeded when it shouldn't have\n");
return 1;
}
/*
* Overlap start of existing mapping:
* base | free | new
* +1 | mapped | new
* +2 | mapped |
* +3 | mapped |
* +4 | free |
*/
errno = 0;
addr = BASE_ADDRESS;
size = 2 * page_size;
p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);
if (p != MAP_FAILED) {
dump_maps();
printf("Error:4: mmap() succeeded when it shouldn't have\n");
return 1;
}
/*
* Adjacent to start of existing mapping:
* base | free | new
* +1 | mapped |
* +2 | mapped |
* +3 | mapped |
* +4 | free |
*/
errno = 0;
addr = BASE_ADDRESS;
size = page_size;
p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);
if (p == MAP_FAILED) {
dump_maps();
printf("Error:5: mmap() failed when it shouldn't have\n");
return 1;
}
/*
* Adjacent to end of existing mapping:
* base | free |
* +1 | mapped |
* +2 | mapped |
* +3 | mapped |
* +4 | free | new
*/
errno = 0;
addr = BASE_ADDRESS + (4 * page_size);
size = page_size;
p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);
if (p == MAP_FAILED) {
dump_maps();
printf("Error:6: mmap() failed when it shouldn't have\n");
return 1;
}
addr = BASE_ADDRESS;
size = 5 * page_size;
if (munmap((void *)addr, size) != 0) {
dump_maps();
printf("Error: munmap failed!?\n");
return 1;
}
printf("unmap() successful\n");
printf("OK\n");
return 0;
}