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selftests/x86: add placement guard gap test for shstk

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The existing shadow stack test for guard gaps just checks that new
mappings are not placed in an existing mapping's guard gap.  Add one that
checks that new mappings are not placed such that preexisting mappings are
in the new mappings guard gap.

Link: https://lkml.kernel.org/r/20240326021656.202649-15-rick.p.edgecombe@intel.com
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Deepak Gupta <debug@rivosinc.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: H. Peter Anvin (Intel) <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Rick Edgecombe 2024-03-25 19:16:56 -07:00 committed by Andrew Morton
parent c44357c2e7
commit a9bc15cb1c
1 changed files with 63 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

67
tools/testing/selftests/x86/test_shadow_stack.c
View File

@ -556,7 +556,7 @@ struct node {
* looked at the shadow stack gaps.
* 5. See if it landed in the gap.
*/
int test_guard_gap(void)
int test_guard_gap_other_gaps(void)
{
void *free_area, *shstk, *test_map = (void *)0xFFFFFFFFFFFFFFFF;
struct node *head = NULL, *cur;
@ -593,11 +593,64 @@ int test_guard_gap(void)
if (shstk - test_map - PAGE_SIZE != PAGE_SIZE)
return 1;
printf("[OK]\tGuard gap test\n");
printf("[OK]\tGuard gap test, other mapping's gaps\n");
return 0;
}
/* Tests respecting the guard gap of the mapping getting placed */
int test_guard_gap_new_mappings_gaps(void)
{
void *free_area, *shstk_start, *test_map = (void *)0xFFFFFFFFFFFFFFFF;
struct node *head = NULL, *cur;
int ret = 0;
free_area = mmap(0, PAGE_SIZE * 4, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
munmap(free_area, PAGE_SIZE * 4);
/* Test letting map_shadow_stack find a free space */
shstk_start = mmap(free_area, PAGE_SIZE, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (shstk_start == MAP_FAILED || shstk_start != free_area)
return 1;
while (test_map > shstk_start) {
test_map = (void *)syscall(__NR_map_shadow_stack, 0, PAGE_SIZE, 0);
if (test_map == MAP_FAILED) {
printf("[INFO]\tmap_shadow_stack MAP_FAILED\n");
ret = 1;
break;
}
cur = malloc(sizeof(*cur));
cur->mapping = test_map;
cur->next = head;
head = cur;
if (test_map == free_area + PAGE_SIZE) {
printf("[INFO]\tNew mapping has other mapping in guard gap!\n");
ret = 1;
break;
}
}
while (head) {
cur = head;
head = cur->next;
munmap(cur->mapping, PAGE_SIZE);
free(cur);
}
munmap(shstk_start, PAGE_SIZE);
if (!ret)
printf("[OK]\tGuard gap test, placement mapping's gaps\n");
return ret;
}
/*
* Too complicated to pull it out of the 32 bit header, but also get the
* 64 bit one needed above. Just define a copy here.
@ -850,9 +903,15 @@ int main(int argc, char *argv[])
goto out;
}
if (test_guard_gap()) {
if (test_guard_gap_other_gaps()) {
ret = 1;
printf("[FAIL]\tGuard gap test\n");
printf("[FAIL]\tGuard gap test, other mappings' gaps\n");
goto out;
}
if (test_guard_gap_new_mappings_gaps()) {
ret = 1;
printf("[FAIL]\tGuard gap test, placement mapping's gaps\n");
goto out;
}